WO2018135434A1 - Cd-free colloidal quantum dot capable of emitting visible fluorescence, and method for producing same - Google Patents

Cd-free colloidal quantum dot capable of emitting visible fluorescence, and method for producing same Download PDF

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WO2018135434A1
WO2018135434A1 PCT/JP2018/000807 JP2018000807W WO2018135434A1 WO 2018135434 A1 WO2018135434 A1 WO 2018135434A1 JP 2018000807 W JP2018000807 W JP 2018000807W WO 2018135434 A1 WO2018135434 A1 WO 2018135434A1
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colloidal quantum
liquid
raw material
temperature
quantum dots
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PCT/JP2018/000807
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French (fr)
Japanese (ja)
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孝久 小俣
宇野　貴博
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三菱マテリアル株式会社
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Priority claimed from JP2017248935A external-priority patent/JP2018115315A/en
Application filed by 三菱マテリアル株式会社 filed Critical 三菱マテリアル株式会社
Priority to EP18741280.4A priority Critical patent/EP3572482A4/en
Priority to KR1020197023225A priority patent/KR20190104583A/en
Priority to US16/478,208 priority patent/US20190367810A1/en
Priority to CN201880007299.XA priority patent/CN110199006A/en
Publication of WO2018135434A1 publication Critical patent/WO2018135434A1/en

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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/88—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing selenium, tellurium or unspecified chalcogen elements
    • C09K11/881—Chalcogenides
    • C09K11/883—Chalcogenides with zinc or cadmium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
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    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/56—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing sulfur
    • C09K11/562—Chalcogenides
    • C09K11/565—Chalcogenides with zinc cadmium
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/62—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing gallium, indium or thallium
    • C09K11/621—Chalcogenides
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
    • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
    • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
    • C09K11/70—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing phosphorus
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
    • H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
    • H01L33/50—Wavelength conversion elements
    • H01L33/501—Wavelength conversion elements characterised by the materials, e.g. binder
    • H01L33/502—Wavelength conversion materials

Definitions

  • the present invention relates to a colloidal quantum dot that emits visible fluorescence, which is a kind of photoluminescent material, and a method for producing the same. More specifically, a colloidal quantum dot that does not contain Cd and emits visible fluorescence having emission wavelength controllability (particle size controllability), full width at half maximum (FWHM) of emission spectrum, and Stokes shift equivalent to that of a CdSe-based colloidal quantum dot, and its It relates to a manufacturing method. In particular, the present invention relates to a colloidal quantum dot not containing Cd that emits green or red visible fluorescence equivalent to a CdSe-based colloidal quantum dot and a method for producing the same.
  • This international application includes Japanese Patent Application No.
  • Japanese Patent Application No. 2017-6353 filed on January 18, 2017
  • Japanese Patent Application No. 248935 Japanese Patent Application No. 248935
  • December 26, 2017. No. 2017-248935 Japanese Patent Application No. 2017-248935
  • the optical filter is used to extract the light of the necessary wavelength from the light emission of the phosphor, to improve the color purity, and to achieve good chromaticity, but the optical filter reduces the light transmittance Therefore, the excitation energy must be increased, resulting in a significant reduction in efficiency.
  • One solution to this problem is to use a material that has a sharp emission spectrum, such as a colloidal quantum dot, and that can freely control the emission wavelength by particle size control using the quantum size effect. Can achieve chromaticity.
  • a material that has a sharp emission spectrum such as a colloidal quantum dot
  • a product using a blue LED as a backlight and a colloidal quantum dot phosphor that emits light when excited is commercially available.
  • Non-Patent Document 1 and Non-Patent Document 2 disclose colloidal quantum dots that do not contain Cd that emit green light or red light.
  • Non-Patent Document 1 discloses that a stable InP / ZnS core-shell colloidal quantum dot having high luminescence was developed by adding zinc acetate and dodecanethiol to an InP core solution step by step, and that zinc acetate is on the surface. It has been reported to play an important role in etching and ZnS shell formation.
  • Non-patent document 2 describes the origin of the photoluminescence (PL) particle size dependence of CuInS 2 —ZnS alloy / ZnS core-shell colloidal quantum dots (ternary compound semiconductors) and the effect of thin coating of ZnS on PL characteristics. Has been reported.
  • PL photoluminescence
  • the InP colloidal quantum dots shown in Non-Patent Document 1 have a light emission wavelength that varies greatly due to a slight difference in particle size, particularly in the region shorter than green, so that the particle size can be precisely controlled. Otherwise, it will not be a colloidal quantum dot with good chromaticity, and secondly, it has a large Stokes shift, so there is a large energy loss, and thirdly, the phosphide used as a synthetic raw material is very reactive and dangerous. There is a problem such as.
  • Non-Patent Document 2 the ternary compound semiconductor colloidal quantum dots represented by CuInS 2 shown in Non-Patent Document 2 have a wide solid solution region where a plurality of compounds exist, and synthesize compounds according to the chemical composition.
  • the technology is extremely difficult, and electron-hole recombination is via a defect level.
  • the emission spectrum is broad and the color purity is inferior.
  • a large Stokes shift There is a problem that energy loss is large and green light emission is difficult to realize.
  • the object of the present invention is to solve the above-mentioned problems and to emit Cd that emits visible fluorescence having emission wavelength controllability (particle size controllability), emission spectrum full width at half maximum (FWHM), and Stokes shift equivalent to those of CdSe-based colloidal quantum dots. It is providing the colloidal quantum dot which does not contain and its manufacturing method.
  • an object of the present invention is to provide a colloidal quantum dot not containing Cd that emits green or red visible fluorescence equivalent to that of a CdSe-based colloidal quantum dot and a method for producing the same.
  • the present inventors paid attention to ZnS, ZnSe, and ZnTe as II-VI compound semiconductors not containing Cd.
  • the band gaps in these bulk bodies are 3.83 eV, 2.72 eV, and 2.25 eV, respectively (both of zinc blende type crystals), and the colloidal quantum dots of ZnS and ZnSe emit light in the green or red region. While it is not possible to realize a possible band gap, ZnTe colloidal quantum dots can emit light in the blue-green region using the quantum size effect, but even if the particle size is greatly changed in the green region The change in the emission wavelength remains small, and the controllability of the emission wavelength in the green region is poor.
  • the band gap is as small as 2.03 eV.
  • the present inventors consider that such band gap bowing is realized also in colloidal quantum dots, and by combining the quantum size effect and band gap bowing, the band gap in the green or red region is realized, The invention has been reached.
  • a first aspect of the present invention is a core particle that is coated with a shell made of a compound semiconductor and forms the core of the shell, and emits visible fluorescence when irradiated with excitation light having a wavelength in the near ultraviolet region or blue region. It is a colloidal quantum dot that does not contain emitted Cd.
  • This colloidal quantum dot is represented by the chemical formula A (B1 1-x , B2 x ) (where 0 ⁇ x ⁇ 1), Zn as a group II element at the A site, and Te as a group VI element at the B1 site.
  • the B2 site has Se or S as a group VI element, and has an average particle size of 1 nm or more and 10 nm or less.
  • the second aspect of the present invention is a colloidal quantum dot that is based on the first aspect and does not include Cd in which the B2 site is Se and the visible fluorescence is green light.
  • a third aspect of the present invention is a colloidal quantum dot which is an invention based on the first aspect, wherein the B2 site is S and the visible fluorescence is red light and does not contain Cd.
  • a fourth aspect of the present invention is a first mixed liquid prepared by mixing a Zn raw material liquid, a Te raw material liquid, and a Se raw material liquid, or a second mixed liquid prepared by mixing a capping agent and a diluent. Any one of the above liquids is heated to a temperature of 200 ° C. to 350 ° C., a predetermined amount of the other liquid is injected into the heated one liquid in a non-oxidizing atmosphere, and the other liquid is injected into the one liquid.
  • This is a method for producing a colloidal quantum dot that does not contain Cd whose visible fluorescence is green light by adjusting the temperature of the liquid injected to 200 ° C. to 350 ° C. and holding it for 1 minute to 5 hours.
  • a fifth aspect of the present invention is a third mixed solution prepared by mixing a Zn raw material solution and a Te raw material solution or a fourth mixed solution prepared by mixing an S raw material solution, a capping agent, and a diluent. Any one of the above liquids is heated to a temperature of 200 ° C. to 350 ° C., a predetermined amount of the other liquid is injected into the heated one liquid in a non-oxidizing atmosphere, and the other liquid is injected into the one liquid.
  • This is a method for producing a colloidal quantum dot that does not contain Cd whose visible fluorescence is red light by adjusting the temperature of the solution injected at 200 ° C. to 350 ° C. and holding it for 1 minute to 5 hours.
  • the InP-based colloidal shown in Non-Patent Document 1 when irradiated with excitation light having a wavelength in the near-ultraviolet region or blue region, the InP-based colloidal shown in Non-Patent Document 1
  • the characteristics equivalent to those of the CdSe-based colloidal quantum dots can be realized, exceeding the characteristics of the quantum dots and the colloidal quantum dots of the ternary compound semiconductor shown in Non-Patent Document 2.
  • the influence of the difference in particle size on the change in the emission wavelength becomes small, the emission wavelength can be precisely controlled, and good chromaticity is realized.
  • the full width at half maximum (FWHM) of the emission spectrum is narrowed, and the color purity is improved.
  • the Stokes shift is reduced and energy loss is reduced. In all items, the characteristics are improved to the same level as the CdSe colloidal quantum dots.
  • the B2 site is changed to Se to form a Zn (Te 1-x , Se x ) colloidal quantum dot, whereby the visible fluorescence is changed to green.
  • the visible fluorescence is changed to red by changing the B2 site to S and forming a Zn (Te 1-x , S x ) colloidal quantum dot.
  • the first mixed liquid obtained by mixing the raw material liquids of Zn, Te, and Se and the second mixed liquid obtained by mixing the capping agent and the diluent are mixed together. Since the elements (Zn, Te, Se) are collectively prepared, the molar composition ratio of the colloidal quantum dots can be easily controlled by the molar charge ratio. In addition, since the lower temperature liquid is injected into one higher temperature liquid, the temperature after injection can be greatly changed (decreased), the separation between nucleation and growth is improved, and the colloidal is highly uniform. Since quantum dots are obtained and the grown nuclei are kept at a constant temperature, the particle size can be easily controlled with time, and as a result, colloidal quantum dots containing no Cd whose visible fluorescence is green light are obtained.
  • the third mixed solution obtained by mixing the respective raw material solutions of Zn and Te, and the fourth mixed solution obtained by mixing the S raw material solution, the capping agent, and the diluent are used. Since the lower temperature of the liquid is injected into the higher temperature of the liquid, the post-injection temperature can be greatly changed (decreased), the separation between nucleation and growth is improved, and colloidal quantum dots with high uniformity Furthermore, since the grown nuclei are kept at a constant temperature, the particle size can be easily controlled by time, and as a result, a colloidal quantum dot containing no Cd whose visible fluorescence is red light is obtained.
  • FIG. 4 is a diagram showing a simulation result of a band gap with respect to a Se molar composition ratio x Se in a Zn (Te 1-x , Se x ) colloidal quantum dot having a particle diameter of 2 to 10 nm.
  • Molar ratio x Se of Se is a diagram showing a simulation of the band gap results for the particle size in the Zn (Te 1-x, Se x) colloidal quantum dot when the 0.35.
  • FIG. 4 is a diagram showing a simulation result of a band gap with respect to a molar composition ratio x S of S in a Zn (Te 1-x , S x ) colloidal quantum dot having a particle diameter of 2 to 10 nm. It is a figure which shows the simulation result of the band gap with respect to the particle size in Zn (Te1 -x , Sx ) colloidal quantum dot when the molar composition ratio xS of S is 0.35.
  • Non-Patent Documents 4 and 5 report calculations for theoretically predicting the particle size dependence of the optical gap of colloidal quantum dots. Among them, effective mass approximation calculation that can obtain the same result as other methods by simple notation is convenient.
  • the Schrödinger equation for particles (mass: m) in potential: V (r) is expressed by the following equation (1).
  • a relational expression between the particle size and the optical gap is derived by a model assuming an effective mass approximation in a well-type potential of a finite depth.
  • the confinement potential is expressed as the following equation (2) as a central symmetry V (r) at a finite depth.
  • V (r) the radius of the spherical colloidal quantum dot is r 0 .
  • V 0 is defined as the following equation (3).
  • ⁇ E HOMO-LUMO is the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the surfactant coordinated as a capping agent on the surface of the colloidal quantum dot.
  • Energy difference ⁇ E HOMO-LUMO of oleic acid used as the surfactant is a value obtained by measuring the light absorption spectrum: 4.35 eV.
  • ZnTe, ZnSe, the band gap of the bulk of the ZnS: E g and electron-hole effective mass: m e * / m 0, m h * / m 0 is used the values shown in the following Table 1 .
  • the band gap: E is the band gap of the bulk body of ZnTe, ZnSe, ZnS: E g and the effective mass of electrons / holes: me * / m 0 , M h * / m 0 .
  • the band gap in the mixed crystal bulk body is calculated using the following equations (4) and (5) expressed using the bowing parameter (b).
  • the electron-hole effective mass m e * / m 0, m h * / the additive property assuming the m 0, calculating the relationship between the band gap and the particle size-molar ratio of the colloidal quantum dots is doing.
  • the additivity of the effective mass of electrons of Zn (Te 1-x , Se x ) is expressed by the following formula (6).
  • FIG. 2 shows a simulation result of the band gap with respect to the particle diameter in the Zn (Te 1-x , Se x ) colloidal quantum dot when the Se molar composition ratio x Se is 0.35.
  • the band portion indicates the green light emitting region.
  • FIG. 3 shows the simulation results of the band gap with respect to the molar composition ratio x S of S in Zn (Te 1-x , S x ) colloidal quantum dots having a particle diameter of 2 to 10 nm.
  • FIG. 4 shows a simulation result of the band gap with respect to the particle diameter in a Zn (Te 1-x , S x ) colloidal quantum dot when the molar composition ratio x S of S is 0.35.
  • a band portion indicates a red light emitting region. Taking into account the Stokes shift, which is typically 100 meV, red light is emitted from Zn (Te 1-x , S x ) colloidal quantum dots that do not contain Cd by adjusting the molar composition ratio x S of S and the particle size. Can be realized.
  • the colloidal quantum dot of this embodiment is a core particle that is coated with a shell made of a compound semiconductor and forms the core of the shell, and emits visible fluorescence when irradiated with excitation light having a wavelength in the near ultraviolet region or blue region. It is a colloidal quantum dot that does not contain emitted Cd.
  • This colloidal quantum dot is represented by the chemical formula A (B1 1-x , B2 x ) (where 0 ⁇ x ⁇ 1), Zn as a group II element at the A site, and Te as a group VI element at the B1 site.
  • the B2 site has Se or S as a group VI element, and has an average particle size of 1 nm or more and 10 nm or less.
  • the average particle size is less than 1 nm, it is difficult to control the particle size, and if it exceeds 10 nm, it takes a very long time for grain growth, resulting in poor production efficiency, widening the particle size distribution, and color. Purity deteriorates.
  • isoelectronic trap is obtained by adding a small amount of an element (Se) having the same electron configuration as an element constituting a compound semiconductor (for example, Zn and Te) and substituting a lattice point, This means that electrons or holes are attracted and become bound due to the difference in electron affinity.
  • the light emission mechanism by the isoelectronic trap can be explained by using a coordinate coordinate model indicating the relationship between the lattice displacement and the energy.
  • the excitons in the excited state are trapped in the pit of the excited state potential created by being bound. By entering the depression, the difference from the ground state potential is reduced. Therefore, the transition between the level of the dent and the ground state results in light emission with energy smaller than the band gap of the original compound semiconductor (ZnTe).
  • a method for producing a colloidal quantum dot of the present invention as a first embodiment, a method for producing a Zn (Te 1-x , Se x ) colloidal quantum dot whose visible fluorescence is green light is described as a second embodiment.
  • the manufacturing method of Zn (Te1 -x , Sx ) colloidal quantum dot whose visible fluorescence is red light is each explained in full detail.
  • the method for producing a colloidal quantum dot that emits green light is prepared by mixing a liquid prepared by mixing a Zn raw material liquid, a Te raw material liquid, and a Se raw material liquid, or a capping agent and a diluent.
  • One of the two liquids is heated to a temperature of 200 ° C. to 350 ° C., and a predetermined amount of the other liquid is injected into the heated one liquid in a non-oxidizing atmosphere.
  • the liquid into which the other liquid was injected was adjusted to a temperature of 200 ° C. to 350 ° C. and held for 1 minute to 5 hours, thereby producing a colloidal quantum dot containing no Cd whose visible fluorescence is green light. is there.
  • An example of the manufacturing method of the first embodiment is as follows: (a) a step of mixing a Zn raw material liquid, a Te raw material liquid, and a Se raw material liquid to prepare a first mixed liquid; and (b) sealing. (C) adjusting the temperature of the second mixed liquid to 200 ° C. to 350 ° C., and adding the capping agent and diluent to the container and mixing them; In a non-oxidizing atmosphere, a step of injecting a predetermined amount of the first mixture into the second mixture; and (d) a temperature of the solution obtained by injecting the first mixture into the second mixture is 200. And a step of adjusting to a temperature of from 350 to 350 ° C. and holding for 1 minute to 5 hours.
  • the reason why the temperature of the second mixed solution is adjusted to 200 ° C. to 350 ° C. is that if it is less than 200 ° C., rapid nucleation does not occur and the particle size distribution becomes wide, and if it exceeds 350 ° C., This is because volatilization of the organic solvent occurs preferentially and hinders the production of colloidal quantum dots.
  • the adjustment temperature of the second liquid mixture is preferably 250 ° C. to 310 ° C.
  • the temperature of the liquid obtained by injecting the first mixed liquid into the second mixed liquid is set to 200 ° C. to 350 ° C. If the temperature is lower than 200 ° C., the growth rate of the colloid becomes very slow, and the particle size can be controlled by time.
  • a preferred holding temperature is 230 ° C to 300 ° C.
  • the retention time of the liquid obtained by injecting the first mixed liquid into the second mixed liquid is set to 1 minute to 5 hours because the raw material is hardly consumed and the yield is greatly reduced if it is less than 1 minute. Yes, if it exceeds 5 hours, the productivity is poor, and the cost of power consumed during heating during growth greatly increases.
  • the preferred holding time is 10 minutes to 60 minutes.
  • Zn raw material solution liquid diethylzinc (DEZ) or powdered zinc stearate (Zn (St) 2 ) or the like as a Zn source is placed in a container substituted with an inert gas, and trioctylphosphine is added thereto.
  • Organic solvents such as (TOP), octadecene (ODE), acetic acid, oleic acid (OA), stearic acid, hexadecylamine (HDA), oleylamine (OLA), trioctylamine (TOA), tributylphosphonic acid (TBPA) It is prepared by adding a complexing agent) and heating.
  • the organic solvent is not limited to the organic solvents described above as long as the organic solvent forms a complex with Zn ions.
  • the container containing the mixed solution of Zn raw material is heated with an oil bath or the like.
  • the temperature heated in the oil bath is 20 ° C. to 350 ° C., and the holding time at the heated temperature is 5 minutes to 5 hours.
  • the heating temperature is less than 20 ° C. or the holding time is less than 5 minutes, the Zn source is not sufficiently dissolved in the organic solvent (complexing agent), and an undissolved portion of the Zn source is likely to be generated.
  • Te raw material liquid is filled with powdered metal tellurium (Te) as a Te source, powdered tellurium oxide or an available inexpensive and safe organic tellurium compound in a container substituted with an inert gas.
  • Te powdered metal tellurium
  • the same organic solvent (complex forming agent) as used for the preparation of the Zn raw material solution is added and heated.
  • the organic solvent is not limited to the organic solvents described above as long as the organic solvent forms a complex with Te ions.
  • the container containing the Te raw material mixture is heated in an oil bath or the like. The temperature at which the oil bath is heated is 100 ° C. to 350 ° C., and the holding time at the heated temperature is 5 minutes to 5 hours.
  • the Te source When the heating temperature is less than 100 ° C. or the holding time is less than 5 minutes, the Te source is not sufficiently dissolved in the organic solvent (complexing agent), and an undissolved portion of the Te source is likely to be generated. On the other hand, when the heating temperature exceeds 350 ° C., volatilization of the organic solvent (complex forming agent) occurs preferentially, which hinders dissolution of the Te source. When the holding time exceeds 5 hours, the Te source has sufficiently reached dissolution equilibrium, and wasteful power consumption due to heating occurs.
  • the Se raw material liquid is filled with powdered metal selenium (Se) as a Se source, powdered selenium oxide or an available inexpensive and safe organic selenium compound in a container substituted with an inert gas.
  • the same organic solvent (complex forming agent) as used for the preparation of the Zn raw material solution is added and heated. Note that the organic solvent is not limited to the organic solvents described above as long as the organic solvent forms a complex with Se ions.
  • the container containing the Se raw material mixture is heated in an oil bath or the like. The temperature heated in the oil bath is 20 ° C. to 350 ° C., and the holding time at the heated temperature is 5 minutes to 5 hours.
  • the Se source When the heating temperature is less than 20 ° C. or the holding time is less than 5 minutes, the Se source is not sufficiently dissolved in the organic solvent (complexing agent), and the Se source is not easily dissolved. On the other hand, if the heating temperature exceeds 350 ° C., the organic solvent (complexing agent) volatilizes preferentially, which hinders dissolution of the Se source. When the holding time exceeds 5 hours, the Se source has sufficiently reached dissolution equilibrium, and wasteful power consumption due to heating occurs. 1 to 10 mol of an organic solvent (complexing agent) is added to 1 mol of Se source. When the Se raw material is dissolved, the mixed solution becomes transparent.
  • preparation of Se raw material liquid is not limited to said preparation conditions, Conditions can be adjusted according to the combination with the solvent for complex formation to be used.
  • the first mixed liquid is a mixture of a Zn raw material liquid, a Te raw material liquid, and a Se raw material liquid in a container substituted with an inert gas so as to have a predetermined molar composition ratio. Prepared with stirring.
  • the second mixed liquid is a mixture of a capping agent and a diluent in a container, and after performing a degassing process of “120 ° C. ⁇ 30 minutes” in a vacuum while stirring, it is returned to atmospheric pressure with an inert gas, It is prepared by raising the temperature to 200 ° C. to 350 ° C. using a mantle heater or the like while ventilating an inert gas.
  • Examples of the capping agent include trioctylphosphine (TOP), oleic acid (OA), stearic acid, hexadecylamine (HDA), oleylamine (OLA), tributylphosphonic acid (TBPA), trioctylphosphine oxide (TOPO) and the like. It is done.
  • Examples of the diluent include trioctylphosphine (TOP), octadecene (ODE), oleylamine (OLA), hexadecylamine (HDA), and trioctylphosphine oxide (TOPO). Add 1-5 mol of diluent to 1 mol of capping agent.
  • the first mixed liquid room temperature
  • the injection is performed at a pushing speed of 1 to 20 mL / second using a syringe having an inner diameter of 10 mm.
  • the liquid mixture of Zn raw material liquid, Te raw material liquid, and Se raw material liquid is prepared.
  • a mixing method such as nozzle mixing or ejector mixing may be employed using an inert compressed gas depending on the scale of mixing.
  • the reason why the temperature of the second mixed solution is adjusted to 200 ° C. to 350 ° C. is that if it is less than 200 ° C., rapid nucleation does not occur and the particle size distribution becomes wide, and if it exceeds 350 ° C., This is because volatilization of the organic solvent occurs preferentially and hinders the nucleation of colloidal quantum dots.
  • the average particle size of the obtained colloidal quantum dots can be made constant.
  • the Se molar composition ratio x Se is fixed at around 0.30
  • the temperature of the second mixed solution, the temperature of the solution after the first mixed solution is injected into the second mixed solution, and the holding time are adjusted.
  • the average particle size of the colloidal quantum dots can be adjusted in the range of 3.0 to 7.0 nm.
  • the band gap of the colloidal quantum dots changes due to the quantum size effect, and green light emission (2.15 to 2.45 eV) is realized in the region where the average particle size is 3.0 to 7.0 nm.
  • the method for producing a colloidal quantum dot emitting red light according to the second embodiment is prepared by mixing a Zn raw material liquid and a Te raw material liquid or a S raw material liquid, a capping agent, and a diluent.
  • One of the two liquids is heated to a temperature of 200 ° C. to 350 ° C., and a predetermined amount of the other liquid is injected into the heated one liquid in a non-oxidizing atmosphere.
  • the liquid into which the other liquid was injected was adjusted to a temperature of 200 ° C. to 350 ° C. and held for 1 minute to 5 hours to produce a colloidal quantum dot containing no Cd whose visible fluorescence is red light. is there.
  • C) adjusting the temperature of the fourth mixture to 200 ° C. to 350 ° C., and non-oxidizing the inside of the sealed container A step of injecting a predetermined amount of the third mixed liquid into the fourth mixed liquid in a neutral atmosphere; and (d) the temperature of the liquid injected with the third mixed liquid into the fourth mixed liquid is 200 ° C. to Adjusting to 350 ° C. and holding for 1 minute to 5 hours.
  • the reason why the temperature of the fourth mixed liquid is adjusted to 200 ° C. to 350 ° C.
  • the adjustment temperature of the fourth mixed solution is preferably 260 ° C. to 320 ° C.
  • the temperature of the liquid obtained by injecting the third mixed liquid into the fourth mixed liquid is set to 200 ° C. to 350 ° C. If the temperature is lower than 200 ° C., the growth rate of the colloidal quantum dots becomes very slow.
  • a preferred holding temperature is 240 ° C to 310 ° C.
  • the retention time of the liquid obtained by injecting the third mixed liquid into the fourth mixed liquid is set to 1 minute to 5 hours because the raw material is hardly consumed and the yield is greatly reduced if it is less than 1 minute. Yes, if it exceeds 5 hours, the productivity is poor, and the cost of power consumed during heating during growth greatly increases.
  • the preferred holding time is 10 minutes to 3 hours.
  • the Zn raw material liquid is prepared in the same manner as the Zn raw material liquid used in the above-described method for producing Zn (Te 1-x , Se x ) colloidal quantum dots. 1 to 16 mol of an organic solvent (complexing agent) is added to 1 mol of Zn source. When the Zn raw material is dissolved, the mixed solution becomes transparent.
  • preparation of Zn raw material liquid is not limited to said preparation conditions, Conditions can be adjusted according to the combination with the solvent for complex formation to be used.
  • Te raw material liquid is prepared in the same manner as the Te raw material liquid used in the above-described method for producing Zn (Te 1-x , Se x ) colloidal quantum dots.
  • the S raw material liquid is filled with powdered sulfur (S) as an S source or an available inexpensive and safe organic sulfur compound in a container substituted with an inert gas. It is prepared by adding the same organic solvent (complexing agent) as used and heating. Note that the organic solvent is not limited to the organic solvents described above as long as the organic solvent forms a complex with S ions.
  • the container containing the mixed solution of the S raw material is heated with an oil bath or the like. The temperature heated in the oil bath is 20 ° C. to 350 ° C., and the holding time at the heated temperature is 5 minutes to 5 hours. When the heating temperature is less than 20 ° C.
  • the S source is not sufficiently dissolved in the organic solvent (complexing agent), and an undissolved portion of the S source is likely to be generated.
  • the heating temperature exceeds 350 ° C.
  • the volatilization of the organic solvent (complexing agent) occurs preferentially, which hinders dissolution of the S source.
  • the holding time exceeds 5 hours, the S source has sufficiently reached dissolution equilibrium, and wasteful power consumption due to heating occurs. 1 to 10 mol of an organic solvent (complexing agent) is added to 1 mol of the S source.
  • the mixed solution becomes transparent.
  • preparation of S raw material liquid is not limited to said preparation conditions, Conditions can be adjusted according to the combination with the solvent for complex formation to be used.
  • the third liquid mixture is prepared by mixing the Zn raw material liquid and the Te raw material liquid so as to have a predetermined molar composition ratio in a container substituted with an inert gas, and stirring the mixture while venting the inert gas at room temperature. Is done.
  • the fourth mixed liquid is a mixture of S raw material liquid, capping agent and diluent in a container, and after deaeration treatment at 120 ° C. for 30 minutes in vacuum with stirring, a large amount of inert gas is used.
  • the pressure is adjusted to 200 ° C. to 350 ° C. using a mantle heater or the like while returning to atmospheric pressure and passing an inert gas.
  • Examples of the capping agent include trioctylphosphine (TOP), oleic acid (OA), stearic acid, hexadecylamine (HDA), oleylamine (OLA), tributylphosphonic acid (TBPA), trioctylphosphine oxide (TOPO) and the like. It is done.
  • Examples of the diluent include trioctylphosphine (TOP), octadecene (ODE), oleylamine (OLA), hexadecylamine (HDA), and trioctylphosphine oxide (TOPO). Add 5-30 mol of capping agent and 1-30 mol of diluent to 1 mol of S source.
  • the 3rd liquid mixture (room temperature) is injected into the 4th liquid mixture at once using a syringe or the like, and colloidal quantum dots Generate nuclei.
  • the injection is performed at a pushing speed of 1 to 20 mL / second using a syringe having an inner diameter of 10 mm.
  • nuclei are formed over time, and the particle size distribution becomes wide. At high speeds above the upper limit, the injection operation becomes technically difficult.
  • a synthetic liquid is prepared by mixing the Zn raw material liquid, the Te raw material liquid, and the S raw material liquid.
  • a mixing method such as nozzle mixing or ejector mixing may be employed using an inert compressed gas depending on the scale of mixing.
  • the reason why the temperature of the fourth mixed liquid is adjusted to 200 ° C. to 350 ° C. is that if it is less than 200 ° C., rapid nucleation does not occur and the particle size distribution becomes wide, and if it exceeds 350 ° C., This is because volatilization of the organic solvent occurs preferentially and hinders the production of colloidal quantum dots.
  • the average particle diameter of the obtained colloidal quantum dot can be made constant.
  • the band gap of the colloidal quantum dots changes due to the quantum size effect, and red light emission (1.80 to 2.10 eV). ) Is realized.
  • the raw materials used in the examples and comparative examples of the present invention are as follows. ⁇ raw materials ⁇ The following reagents were prepared. All reagents were not purified and were used commercially. (1) Diethyl zinc (DEZ, ⁇ 52wt% Zn basis, Aldrich), (2) Selenium powder (Se, 100mesh, 99.99%, trace metal basis, Aldrich), (3) Tellurium powder (Te, 100mesh, 99.99% trace metal basis, Aldrich), (4) Tri-n-octylphosphine (TOP, ⁇ 96.0%, Wako Pure Chemical Industries), (5) oleylamine (OLA,> 98%, Aldrich), (6) Oleic acid (OA, 99%, Aldrich), (7) 1-octadecene (ODE,> 90%, Tokyo Kasei), (8) 1-dodecanethiol (DDT,> 95%, Tokyo Kasei), (9) Hexane (> 96%, Wako Pure Chemical) (
  • Example 1 [Synthesis of Zn (Te 1-x , Se x ) colloidal quantum dots]
  • a series of operations from the weighing of the reagent to the end of the synthesis were performed mainly in a glove box filled with nitrogen gas. Operation outside some glove boxes was performed in a sealed container filled with nitrogen gas so that the solution did not come into contact with the atmosphere.
  • Te powder 1.9142 g (15 mmol) and TOP: 50 mL were weighed into a three-necked flask and heated to 250 ° C. while bubbling argon gas, and stirred until the Te powder was completely dissolved and became a yellow transparent color. After dissolution, the mixture was allowed to cool to room temperature to obtain a Te raw material liquid. Further, Se powder: 1.1845 g (15 mmol) and TOP: 50 mL were weighed in a vial and put into an ultrasonic cleaner to completely dissolve Se powder to obtain a colorless and transparent Se raw material liquid.
  • Zn raw material liquid, Te raw material liquid, and Se raw material liquid can also be prepared separately
  • DEZ is in a liquid state, and here, TOP and DEZ are mixed and dissolved in Te raw material liquid and Se raw material liquid, It was set as the 1st liquid mixture.
  • the said 1st liquid mixture was rapidly inject
  • the colloidal quantum dots were grown at a temperature of 270 ° C. for 10 minutes, and then allowed to cool to room temperature.
  • the reaction solution was a clear solution without turbidity.
  • the temperature of the second liquid mixture is 290 ° C.
  • the growth temperature after the first liquid mixture is injected into the second liquid mixture is 270 ° C.
  • the growth time at that temperature is 10 minutes. This is a condition for adjusting the average particle diameter to 4.0 ⁇ 0.1 nm.
  • the particle size of the colloidal quantum dots can be adjusted. Table 2 below shows this condition.
  • Example 2 to 5 and Comparative Example 1 For Examples 2 to 5 and Comparative Example 1, the same Te raw material liquid, Se raw material liquid, TOP, DEZ and the like as in Example 1 were used. In Examples 2 to 5 and Comparative Example 1, these Te raw material liquid, Se raw material liquid, TOP, DEZ, and the like have a molar composition ratio x Se of colloidal quantum dots as shown in Table 2 above. And adjusting the particle size of the colloidal quantum dots by adjusting the temperature of the second mixed solution, the growth temperature after injecting the first mixed solution into the second mixed solution, and the growth time at that temperature. . Otherwise, in the same manner as in Example 1, Zn (Te 1-x , Se x ) / ZnS core-shell colloidal quantum dots were synthesized.
  • the Se raw material solution 1.5 mL was added to a 10 mL vial containing the Zn raw material solution, and after sufficient stirring, the mixture was immersed in an oil bath heated to 280 ° C. and held for 9 minutes while venting argon gas. Thereafter, the vial was taken out from the oil bath and allowed to cool to room temperature. The reaction solution was light yellow and transparent.
  • Example 2 shows the molar composition ratio x Se of the colloidal quantum dots of Comparative Example 2, the temperature of the second mixed liquid, the growth temperature after the first mixed liquid is injected into the second mixed liquid, and the growth at that temperature. Each time is shown.
  • the second mixed liquid which is the same mixed solution of OA and ODE as in Example 1, was heated to 310 ° C. while agitating and stirring argon gas. After confirming that the temperature of this 2nd liquid mixture was stabilized, the said 1st liquid mixture was rapidly inject
  • Example 7 to 12 For Examples 7 to 12, the same Te raw material liquid, Se raw material liquid, TOP, DEZ and the like as in Example 1 were used. In Examples 7 to 12, these Te raw material liquid, Se raw material liquid, TOP, DEZ, and the like were weighed so that the molar composition ratio of Se of colloidal quantum dots xSe as shown in Table 3 above. The particle size of the colloidal quantum dots was adjusted by adjusting the temperature of the second liquid mixture, the growth temperature after injecting the first liquid mixture into the second liquid mixture, and the growth time at that temperature. Otherwise, in the same manner as in Example 6, Zn (Te 1-x , Se x ) / ZnS core-shell colloidal quantum dots were synthesized.
  • tris (trimethylsilyl) phosphine (P (SiC 3 H 9 ) 3 ): 0.02 mmol was dissolved in ODE (C 18 H 36 ): 3 mL to prepare a P raw material solution.
  • the In raw material liquid was returned to atmospheric pressure with argon gas, and the temperature was raised to 300 ° C. while aerated and stirred with argon gas.
  • the P raw material solution weighed in a predetermined amount with a syringe was quickly injected into the heated In raw material solution, and then immediately cooled to room temperature to prepare an InP core colloidal quantum dot reaction solution.
  • the InP / ZnS core-shell colloidal quantum dot reaction liquid was cooled to room temperature, and isopropanol (C 3 H 8 O): 40 mL was added to the cooled liquid to aggregate the InP / ZnS core-shell colloidal quantum dots.
  • the precipitate recovered by centrifugation was redispersed with an appropriate amount of toluene (C 7 H 8 ), and a series of steps of aggregation with isopropanol, recovery by centrifugation, and redispersion with toluene were repeated several times.
  • the finally obtained precipitate by centrifugation was vacuum-dried at room temperature, and the remaining organic solvent was removed to obtain InP / ZnS core-shell colloidal quantum dots.
  • Zinc-sulfur solution: 2.5 mL, copper solution: 1.25 mL, and In solution: 1.25 mL were weighed and mixed, then heated to 200 ° C. while bubbling argon gas and maintained for 60 seconds.
  • a CuInS 2 —ZnS alloy core colloidal quantum dot reaction solution was prepared.
  • CuInS 2 —ZnS alloy core colloidal quantum dot 2.26 mg was taken out from 1.0 mL of the above CuInS 2 —ZnS alloy core colloidal quantum dot reaction solution.
  • this is used as a capping agent OA (C 18 H 34 O 2 ): 32 ⁇ L of zinc diethyldithiocarbamate concentration: 5.5 mM TOP and ODE mixed solution: Redispersed to 1.5 mL.
  • Se powder 94.8 mg (1.2 mmol) is weighed into a 12 mL screw cap bottle, TOP: 5.0 mL is added, and the powder is easily dissolved by stirring with a tube mixer and ultrasonic waves. A liquid was prepared. This Se raw material liquid was colorless and transparent.
  • the Cd raw material solution 2.0 mL and the Se raw material solution: 1.0 mL were collected and mixed in a 12 mL screw mouth bottle.
  • As a capping agent 150 ⁇ L of octylamine was added. After stirring well with a tube mixer, it was immersed in an oil bath at 280 ° C. and subjected to a heating reaction for a predetermined time until it grew to a particle size emitting green light.
  • Reaction solution About 3.0 mL was divided into test tubes, and 4-fold amount (12.0 mL) of butanol was added for dilution. Next, 2 times the amount of methanol (6.0 mL) was added to the diluted solution to aggregate the quantum dots. Centrifugation was carried out for 15 minutes to separate a colorless and transparent supernatant solution and a bright red precipitate, and the supernatant solution was removed.
  • Zn (st) 2 31.6 mg (0.05 mmol) was weighed into a 12 mL screw mouth bottle, and ODE: 2.0 mL was added. This solution was heated in an oil bath at 140 ° C. for about 10 minutes to melt the powder. When the screw cap bottle was pulled up and cooled to room temperature, the powder re-deposited but was used as it was. S used dodecanethiol as a solvent and S raw material.
  • Example 13 [Synthesis of Zn (Te 1-x , S x ) colloidal quantum dots]
  • a series of operations from the weighing of reagents to the end of synthesis were carried out in a glove box mainly filled with nitrogen gas, as in Example 1. I went there. The operation outside some glove boxes was performed in a sealed container filled with nitrogen gas in the same manner as in Example 1 so that the solution did not come into contact with the atmosphere.
  • Te raw material liquid Te powder: 114.8 mg (0.90 mmol) and TOP: 3.00 mL (6.72 mmol) were weighed into a 10 mL septum vial and heated to 200 ° C. while bubbling argon gas, and the Te powder was completely dissolved. The mixture was stirred until it became a yellow transparent color. After dissolution, the mixture was allowed to cool to room temperature to obtain a Te raw material liquid (0.3M).
  • Diethyl zinc (DEZ) as a raw material liquid 25 ⁇ L (0.25 mmol) was added, and the total volume was adjusted to 2 mL with TOP.
  • DEZ Diethyl zinc
  • the color of the solution changed from yellow transparent to colorless and transparent.
  • a mixed solution obtained by mixing the Zn raw material liquid and the Te raw material liquid was used as a third mixed liquid.
  • the reaction solution was a clear solution without turbidity.
  • the temperature of the fourth mixed solution is set to 300 ° C.
  • the growth temperature after the third mixed solution is injected into the fourth mixed solution is set to 290 ° C.
  • the growth time at that temperature is set to 15 minutes. This is a condition for adjusting the average particle diameter to 6.0 ⁇ 0.1 nm.
  • Example 14 to 17 and Comparative Example 6 For Examples 14 to 17 and Comparative Example 6, the same Te raw material liquid, S raw material liquid, TOP, DEZ and the like as in Example 13 were used. In Examples 14 to 17 and Comparative Example 6, these Te raw material liquid, S raw material liquid, TOP, DEZ, and the like have a molar composition ratio x S of S of colloidal quantum dots as shown in Table 4 above. And adjusting the temperature of the fourth mixed solution, the growth temperature after injecting the third mixed solution into the fourth mixed solution, and the growth time at that temperature to adjust the particle size of the colloidal quantum dots to 6. Adjusted to 0 ⁇ 0.1 nm. Otherwise, in the same manner as in Example 13, a Zn (Te 1-x , S x ) / ZnS core-shell colloidal quantum dot was synthesized.
  • the S powder was completely dissolved in an ultrasonic cleaner to prepare a colorless and transparent S raw material solution.
  • Example 19 to 24 In Examples 19 to 24, these Te raw material liquids, TOP, DEZ, and the like are weighed so that the molar composition ratio x S of S of colloidal quantum dots is as shown in Table 5 above, and the S raw material Is measured so as to have a molar composition ratio x S of S , and the temperature of the fourth mixed solution prepared by adding OA and ODE thereto, the growth temperature after injecting the third mixed solution into the fourth mixed solution, The particle size of the colloidal quantum dots was adjusted by adjusting the growth time at that temperature. Other than that was carried out similarly to Example 18, and the Zn (Te1 -x , Sx ) / ZnS core-shell colloidal quantum dot was synthesize
  • a CuInS 2 —ZnS alloy core colloidal quantum dot reaction liquid was prepared in the same manner as in Comparative Example 4 except that this was maintained for 3 minutes, and then a CuInS 2 —ZnS alloy / ZnS core shell colloidal quantum dot was obtained.
  • the average particle diameter of colloidal quantum dots was calculated by using a powder X-ray diffraction measurement method (XRD: X-ray diffraction). Using an X-ray diffractometer (RINT2500, Rigaku) equipped with a rotating cathode X-ray generation source and a curved monochromator, Cu-K ⁇ rays generated at an X-ray acceleration voltage of 40 kV and current of 375 mA (15 kW) It was measured by irradiating colloidal quantum dots on a reflective quartz plate.
  • XRD powder X-ray diffraction measurement method
  • the average particle diameter d XRD was calculated from the full width at half maximum (FWHM) of the diffraction pattern obtained by XRD using the Scherrer equation shown in the following equation (8).
  • B is the half width [rad] of the diffraction pattern
  • ⁇ is the diffraction angle [rad].
  • 0.9 was used for the Scherrer constant.
  • the average particle diameter d XRD was obtained from the linear approximation by the least square method of the cos ⁇ and 0.9 ⁇ / B plots of the diffraction patterns on the diffraction planes of the (111) plane, the (220) plane, and the (311) plane.
  • d XRD 0.9 ⁇ / Bcos ⁇ (8)
  • the molar feed ratio (x Se ) of Se was adjusted within the range of 0 ⁇ x Se ⁇ 1, Zn
  • the emission energy of the (Te 1-x , Se x ) colloidal quantum dots could be controlled to a desired value in the green region: 2.15 to 2.45 eV.
  • the Se molar charge ratio (x Se ) is in the range of 0.25 to 0.40
  • the Zn (Te 1-x , Se x ) colloidal quantum dot exhibits a minimum emission energy of about 2.3 eV. It was.
  • Table 3 above shows the synthesis conditions of colloidal quantum dots when the average particle size is adjusted by setting the Se molar charge ratio (x Se ) of Zn (Te 1-x , Se x ) to be constant at 0.30. .
  • the Se feed ratio (x Se ) is adjusted to 0.30
  • the temperature of the second mixed solution which is a mixed solution of OA and ODE
  • the first mixing which is a raw material solution
  • the average particle size is adjusted to 3.5 to 6.3 nm.
  • the emission energy of the Te 1-x , Se x ) colloidal quantum dots could be adjusted to the green region: 2.15 to 2.45 eV.
  • the green wavelength required for the color gamut expansion is about 530 nm (2.33 to 2.34 eV).
  • “Compliance” item “Yes” is indicated when conforming, and “None” when not conforming.
  • the colloidal quantum dots of Example 7 were made of InP / ZnS (Comparative Example 3), which is a representative example of colloidal quantum dots that do not contain Cd whose visible fluorescence is green, and ternary compound semiconductors ( When compared with Comparative Example 4), first, the average particle size can be increased, so the emission wavelength controllability is greatly improved, and second, the full width at half maximum (FWHM) of the emission spectrum is sharp. Therefore, the chromaticity better than that of the existing colloidal quantum dots not containing Cd can be realized, and the gamut expansion is expected. Third, the Stokes shift is greatly reduced, and the energy loss is greatly reduced.
  • FWHM full width at half maximum
  • the molar charge ratio (x S ) of S is adjusted in the range of 0 ⁇ x S ⁇ 1, Zn (Te).
  • the emission energy of the 1-x , S x ) colloidal quantum dots could be controlled to a desired value within the red region: 1.80 to 2.10 eV.
  • the Zn (Te 1-x , S x ) colloidal quantum dot exhibits a minimum emission energy of 1.96 eV. It was.
  • Table 5 shows the synthesis conditions for colloidal quantum dots when the average particle size is adjusted with the S molar charge ratio (x S ) of Zn (Te 1-x , S x ) kept constant at 0.35. .
  • the colloidal quantum dots emitting visible fluorescence of the present invention can be used in the fields of displays, illumination, medical images, biosensors, LEDs, and lasers.

Abstract

A Cd-free colloidal quantum dot which is a core particle that is coated with a shell made from a compound semiconductor and serves as a core for the shell, and which can emit visible fluorescence upon the irradiation with excited light having a wavelength falling within a near ultraviolet region or a blue region. The colloidal quantum dot is represented by the chemical formula: A(B11-x,B2x) (wherein 0 < x < 1), has Zn as a Group-II element in the A site, has Te as a Group-VI element in the B1 site and has Se or S as a Group-VI element in the B2 site, and has an average particle diameter of 1 to 10 nm inclusive.

Description

可視蛍光を発するＣｄを含まないコロイダル量子ドット及びその製造方法Colloidal quantum dots that do not contain Cd and emit visible fluorescence, and methods for producing the same
　本発明は、光ルミネセンス材料の一種の可視蛍光を発するコロイダル量子ドット及びその製造方法に関する。更に詳しくは、ＣｄＳｅ系のコロイダル量子ドットと同等の発光波長制御性（粒径制御性）、発光スペクトルの半値全幅（ＦＷＨＭ）及びストークスシフトを有する可視蛍光を発するＣｄを含まないコロイダル量子ドット及びその製造方法に関する。特に、ＣｄＳｅ系のコロイダル量子ドットと同等の緑色又は赤色の可視蛍光を発するＣｄを含まないコロイダル量子ドット及びその製造方法に関するものである。なお、本国際出願は、２０１７年１月１８日に出願した日本国特許出願第６３５３号（特願２０１７－６３５３）及び２０１７年１２月２６日に出願した日本国特許出願第２４８９３５号（特願２０１７－２４８９３５）に基づく優先権を主張するものであり、特願２０１７－６３５３及び特願２０１７－２４８９３５の全内容を本国際出願に援用する。 The present invention relates to a colloidal quantum dot that emits visible fluorescence, which is a kind of photoluminescent material, and a method for producing the same. More specifically, a colloidal quantum dot that does not contain Cd and emits visible fluorescence having emission wavelength controllability (particle size controllability), full width at half maximum (FWHM) of emission spectrum, and Stokes shift equivalent to that of a CdSe-based colloidal quantum dot, and its It relates to a manufacturing method. In particular, the present invention relates to a colloidal quantum dot not containing Cd that emits green or red visible fluorescence equivalent to a CdSe-based colloidal quantum dot and a method for producing the same. This international application includes Japanese Patent Application No. 6353 (Japanese Patent Application No. 2017-6353) filed on January 18, 2017 and Japanese Patent Application No. 248935 (Japanese Patent Application No. 248935) filed on December 26, 2017. No. 2017-248935), and the entire contents of Japanese Patent Application No. 2017-6353 and Japanese Patent Application No. 2017-248935 are incorporated herein by reference.
　近年、液晶ディスプレイ（ＬＣＤ）では、画素の高精細化と広色域化の要望が高まっている。広色域化の実現には、バックライトに使われる赤色（Ｒ）・緑色（Ｇ）・青色（Ｂ）の各色の色純度を高め、良好な色度に設定する必要がある。励起光に用いる青色ＬＥＤは、シャープな発光スペクトルを有し、高い色純度が得られており、良好な色度に設定できる。しかし、青色ＬＥＤ光で励起され、緑色光又は赤色光を発するバルク蛍光体で、変換効率に優れ、高い色純度を有し、良好な色度に設定できる材料が今のところ存在しないため、緑色領域と赤色領域での色域拡大が難しい。現状は、光学フィルターを用いて、蛍光体の発光から必要な波長の光を取り出し、色純度を高め、良好な色度を実現する対策が取られているが、光学フィルターによって光透過率が低下するため、励起エネルギーを上げなければならず、その結果、効率が著しく低下してしまう。光学フィルターを用いずに、高いエネルギー変換効率で広色域化するための方法が必要である。 In recent years, there has been an increasing demand for liquid crystal displays (LCDs) with higher pixel definition and wider color gamut. In order to realize a wide color gamut, it is necessary to increase the color purity of each of the red (R), green (G), and blue (B) colors used in the backlight and to set a good chromaticity. The blue LED used for the excitation light has a sharp emission spectrum, has high color purity, and can be set to good chromaticity. However, there is currently no bulk phosphor that is excited by blue LED light and emits green light or red light, and has excellent conversion efficiency, high color purity, and good chromaticity. It is difficult to expand the color gamut in the red and red areas. At present, the optical filter is used to extract the light of the necessary wavelength from the light emission of the phosphor, to improve the color purity, and to achieve good chromaticity, but the optical filter reduces the light transmittance Therefore, the excitation energy must be increased, resulting in a significant reduction in efficiency. There is a need for a method for widening the color gamut with high energy conversion efficiency without using an optical filter.
　この問題の解決法の一つとして、コロイダル量子ドットのように、シャープな発光スペクトルを有し、量子サイズ効果を利用して粒径制御により自在に発光波長を制御できる材料を用いると、所望の色度を実現できる。一部のＬＣＤにおいては、バックライトに青色ＬＥＤと、それにより励起されて発光するコロイダル量子ドット蛍光体を用いた製品が市販された例がある。 One solution to this problem is to use a material that has a sharp emission spectrum, such as a colloidal quantum dot, and that can freely control the emission wavelength by particle size control using the quantum size effect. Can achieve chromaticity. In some LCDs, there are examples in which a product using a blue LED as a backlight and a colloidal quantum dot phosphor that emits light when excited is commercially available.
　従来、コロイダル量子ドット材料としてＣｄＳｅ／ＺｎＳが用いられているが、その毒性が問題となっている。そのため、Ｃｄを含まないコロイダル量子ドット材料の研究開発が広く行われており、近年、特に活発化している。例えば、緑色光又は赤色光を発するＣｄを含まないコロイダル量子ドットが非特許文献１及び非特許文献２に開示されている。 Conventionally, CdSe / ZnS has been used as a colloidal quantum dot material, but its toxicity is a problem. Therefore, research and development of colloidal quantum dot materials that do not contain Cd have been widely carried out, and in recent years have become particularly active. For example, Non-Patent Document 1 and Non-Patent Document 2 disclose colloidal quantum dots that do not contain Cd that emit green light or red light.
　非特許文献１には、酢酸亜鉛とドデカンチオールをＩｎＰコア溶液に段階的に添加することにより、高い発光性を有する安定なＩｎＰ／ＺｎＳコアシェルコロイダル量子ドットが開発されたこと、及び酢酸亜鉛が表面エッチングとＺｎＳシェル形成に重要な役割を果たすことが報告されている。非特許文献２には、ＣｕＩｎＳ2－ＺｎＳ合金／ＺｎＳコアシェルコロイダル量子ドット（三元系化合物半導体）の光ルミネセンス（ＰＬ）の粒径依存に関する起源と、ＺｎＳの薄いコーティングがＰＬ特性に与える効果が報告されている。 Non-Patent Document 1 discloses that a stable InP / ZnS core-shell colloidal quantum dot having high luminescence was developed by adding zinc acetate and dodecanethiol to an InP core solution step by step, and that zinc acetate is on the surface. It has been reported to play an important role in etching and ZnS shell formation. Non-patent document 2 describes the origin of the photoluminescence (PL) particle size dependence of CuInS 2 —ZnS alloy / ZnS core-shell colloidal quantum dots (ternary compound semiconductors) and the effect of thin coating of ZnS on PL characteristics. Has been reported.
　非特許文献１に示されるＩｎＰ系のコロイダル量子ドットには、第一に、特に緑色より短波長の領域において僅かな粒径の違いによって発光波長が大きく変化するので、粒径を精密に制御できなければ、良好な色度のコロイダル量子ドットにはならず、第二に、大きなストークスシフトを有するので、エネルギーロスが大きく、第三に、合成原料となるリン化物は非常に反応性が高く危険である等の課題がある。 First, the InP colloidal quantum dots shown in Non-Patent Document 1 have a light emission wavelength that varies greatly due to a slight difference in particle size, particularly in the region shorter than green, so that the particle size can be precisely controlled. Otherwise, it will not be a colloidal quantum dot with good chromaticity, and secondly, it has a large Stokes shift, so there is a large energy loss, and thirdly, the phosphide used as a synthetic raw material is very reactive and dangerous. There is a problem such as.
　また、非特許文献２に示されるＣｕＩｎＳ2に代表される三元系化合物半導体のコロイダル量子ドットには、第一に、複数の化合物が存在する固溶域が広く、化学式組成通りの化合物を合成する技術の難易度が非常に高く、電子－正孔の再結合は欠陥準位を介したものになるため、第二に、発光スペクトルがブロードで色純度が劣り、第三に、大きなストークスシフトを有し、エネルギーロスが大きく、緑色発光の実現が困難である等の課題がある。 In addition, the ternary compound semiconductor colloidal quantum dots represented by CuInS 2 shown in Non-Patent Document 2 have a wide solid solution region where a plurality of compounds exist, and synthesize compounds according to the chemical composition. The technology is extremely difficult, and electron-hole recombination is via a defect level. Second, the emission spectrum is broad and the color purity is inferior. Third, a large Stokes shift There is a problem that energy loss is large and green light emission is difficult to realize.
　本発明の目的は、上記課題を解決した、ＣｄＳｅ系のコロイダル量子ドットと同等の発光波長制御性（粒径制御性）、発光スペクトルの半値全幅（ＦＷＨＭ）及びストークスシフトを有する可視蛍光を発するＣｄを含まないコロイダル量子ドット及びその製造方法を提供することにある。特に、ＣｄＳｅ系のコロイダル量子ドットと同等の緑色又は赤色の可視蛍光を発するＣｄを含まないコロイダル量子ドット及びその製造方法を提供することにある。 The object of the present invention is to solve the above-mentioned problems and to emit Cd that emits visible fluorescence having emission wavelength controllability (particle size controllability), emission spectrum full width at half maximum (FWHM), and Stokes shift equivalent to those of CdSe-based colloidal quantum dots. It is providing the colloidal quantum dot which does not contain and its manufacturing method. In particular, an object of the present invention is to provide a colloidal quantum dot not containing Cd that emits green or red visible fluorescence equivalent to that of a CdSe-based colloidal quantum dot and a method for producing the same.
　本発明者らは、Ｃｄを含まないII－VI化合物半導体としてＺｎＳ、ＺｎＳｅ、ＺｎＴｅに着目した。これらのバルク体におけるバンドギャップはそれぞれ３．８３ｅＶ、２．７２ｅＶ、２．２５ｅＶ（いずれも閃亜鉛鉱型結晶の場合）であり、ＺｎＳ、ＺｎＳｅのコロイダル量子ドットでは、緑色又は赤色領域の発光を可能にするバンドギャップを実現することはできない一方、ＺｎＴｅのコロイダル量子ドットでは、量子サイズ効果を利用して青緑色領域での発光が可能であるが、緑色領域において粒径を大きく変化させても発光波長の変化は小さいままにとどまり、緑色領域における発光波長の制御性が悪い。 The present inventors paid attention to ZnS, ZnSe, and ZnTe as II-VI compound semiconductors not containing Cd. The band gaps in these bulk bodies are 3.83 eV, 2.72 eV, and 2.25 eV, respectively (both of zinc blende type crystals), and the colloidal quantum dots of ZnS and ZnSe emit light in the green or red region. While it is not possible to realize a possible band gap, ZnTe colloidal quantum dots can emit light in the blue-green region using the quantum size effect, but even if the particle size is greatly changed in the green region The change in the emission wavelength remains small, and the controllability of the emission wavelength in the green region is poor.
　バンドギャップを制御する方法として化合物の混晶化が挙げられ、化合物の混晶化により、バンドギャップが組成に関して負に湾曲するバンドギャップボーイングが生じることがバルク体の結晶において知られている。特に、Ｚｎ（Ｔｅ，Ｓ）、Ｚｎ（Ｔｅ，Ｓｅ）、Ｚｎ（Ｔｅ，Ｏ）のようにアニオンを混晶化した場合、巨大なバンドギャップボーイングが生じ、混晶化していない単一化合物のバンドギャップよりも小さくなる。例えば、非特許文献３には、ＭＯＣＶＤによりＧａＡｓ基板上に成膜したＺｎ（Ｔｅ1-x，Ｓｅx）膜においてバンドギャップボーイングが確認されており、Ｓｅのモル組成比ｘSe＝０．３５でバンドギャップが最大で２．０３ｅＶまで小さくなることが報告されている。本発明者らは、コロイダル量子ドットにおいても、このようなバンドギャップボーイングが実現すると考え、量子サイズ効果とバンドギャップボーイングとを組み合わせることで、緑色又は赤色領域におけるバンドギャップの制御を実現し、本発明に到達した。 As a method for controlling the band gap, compound crystallization can be mentioned. It is known in the bulk crystal that the compound crystallization causes band gap bowing in which the band gap is negatively curved with respect to the composition. In particular, when anions are mixed into crystals such as Zn (Te, S), Zn (Te, Se), Zn (Te, O), a huge band gap bowing occurs, and a single compound that is not mixed is formed. It becomes smaller than the band gap. For example, in Non-Patent Document 3, band gap bowing is confirmed in a Zn (Te 1-x , Se x ) film formed on a GaAs substrate by MOCVD, and the molar composition ratio of Se x Se = 0.35. It is reported that the band gap is as small as 2.03 eV. The present inventors consider that such band gap bowing is realized also in colloidal quantum dots, and by combining the quantum size effect and band gap bowing, the band gap in the green or red region is realized, The invention has been reached.
　本発明の第１の観点は、化合物半導体からなるシェルで被覆され、前記シェルのコアをなすコア粒子であって、近紫外領域又は青色領域の波長を有する励起光を照射したときに可視蛍光を発するＣｄを含まないコロイダル量子ドットである。このコロイダル量子ドットは、化学式Ａ（Ｂ１1-x，Ｂ２x）（ただし、０＜ｘ＜１）で表され、ＡサイトにII族元素としてのＺｎを、Ｂ１サイトにVI族元素としてのＴｅを、Ｂ２サイトにVI族元素としてのＳｅ又はＳをそれぞれ有し、平均粒径が１ｎｍ以上１０ｎｍ以下であることを特徴とする。 A first aspect of the present invention is a core particle that is coated with a shell made of a compound semiconductor and forms the core of the shell, and emits visible fluorescence when irradiated with excitation light having a wavelength in the near ultraviolet region or blue region. It is a colloidal quantum dot that does not contain emitted Cd. This colloidal quantum dot is represented by the chemical formula A (B1 1-x , B2 x ) (where 0 <x <1), Zn as a group II element at the A site, and Te as a group VI element at the B1 site. The B2 site has Se or S as a group VI element, and has an average particle size of 1 nm or more and 10 nm or less.
　本発明の第２の観点は、第１の観点に基づく発明であって、前記Ｂ２サイトがＳｅであって、可視蛍光が緑色光であるＣｄを含まないコロイダル量子ドットである。 The second aspect of the present invention is a colloidal quantum dot that is based on the first aspect and does not include Cd in which the B2 site is Se and the visible fluorescence is green light.
　本発明の第３の観点は、第１の観点に基づく発明であって、前記Ｂ２サイトがＳであって、可視蛍光が赤色光であるＣｄを含まないコロイダル量子ドットである。 A third aspect of the present invention is a colloidal quantum dot which is an invention based on the first aspect, wherein the B2 site is S and the visible fluorescence is red light and does not contain Cd.
　本発明の第４の観点は、Ｚｎ原料液とＴｅ原料液とＳｅ原料液とを混合して調製された第１混合液又はキャッピング剤と希釈剤とを混合して調製された第２混合液のいずれか一方の液を２００℃～３５０℃の温度に加熱し、前記加熱した一方の液に前記いずれか他方の液を非酸化性雰囲気下で所定量注入し、前記一方の液に前記他方の液を注入した液を２００℃～３５０℃の温度に調整し、１分～５時間保持することにより、可視蛍光が緑色光であるＣｄを含まないコロイダル量子ドットを製造する方法である。 A fourth aspect of the present invention is a first mixed liquid prepared by mixing a Zn raw material liquid, a Te raw material liquid, and a Se raw material liquid, or a second mixed liquid prepared by mixing a capping agent and a diluent. Any one of the above liquids is heated to a temperature of 200 ° C. to 350 ° C., a predetermined amount of the other liquid is injected into the heated one liquid in a non-oxidizing atmosphere, and the other liquid is injected into the one liquid. This is a method for producing a colloidal quantum dot that does not contain Cd whose visible fluorescence is green light by adjusting the temperature of the liquid injected to 200 ° C. to 350 ° C. and holding it for 1 minute to 5 hours.
　本発明の第５の観点は、Ｚｎ原料液とＴｅ原料液とを混合して調製された第３混合液又はＳ原料液とキャッピング剤と希釈剤とを混合して調製された第４混合液のいずれか一方の液を２００℃～３５０℃の温度に加熱し、前記加熱した一方の液に前記いずれか他方の液を非酸化性雰囲気下で所定量注入し、前記一方の液に前記他方の液を注入した液を２００℃～３５０℃の温度に調整し、１分～５時間保持することにより、可視蛍光が赤色光であるＣｄを含まないコロイダル量子ドットを製造する方法である。 A fifth aspect of the present invention is a third mixed solution prepared by mixing a Zn raw material solution and a Te raw material solution or a fourth mixed solution prepared by mixing an S raw material solution, a capping agent, and a diluent. Any one of the above liquids is heated to a temperature of 200 ° C. to 350 ° C., a predetermined amount of the other liquid is injected into the heated one liquid in a non-oxidizing atmosphere, and the other liquid is injected into the one liquid. This is a method for producing a colloidal quantum dot that does not contain Cd whose visible fluorescence is red light by adjusting the temperature of the solution injected at 200 ° C. to 350 ° C. and holding it for 1 minute to 5 hours.
　本発明の第１の観点の可視蛍光を発するＣｄを含まないコロイダル量子ドットでは、近紫外領域又は青色領域の波長を有する励起光を照射したときに、非特許文献１に示されるＩｎＰ系のコロイダル量子ドット及び非特許文献２に示される三元系化合物半導体のコロイダル量子ドットの特性を上回って、ＣｄＳｅ系のコロイダル量子ドットと同等の特性を実現できる。具体的には、特に短波長領域において粒径の違いが発光波長の変化に与える影響が小さくなり、発光波長の精密な制御が可能となり、良好な色度が実現する。また、発光スペクトルの半値全幅（ＦＷＨＭ）が狭くなり、色純度が向上する。また、ストークスシフトが小さくなり、エネルギーロスが低減する。全ての項目でＣｄＳｅ系のコロイダル量子ドットと同等レベルまで特性が改善される。 In the colloidal quantum dot that does not contain Cd and emits visible fluorescence according to the first aspect of the present invention, when irradiated with excitation light having a wavelength in the near-ultraviolet region or blue region, the InP-based colloidal shown in Non-Patent Document 1 The characteristics equivalent to those of the CdSe-based colloidal quantum dots can be realized, exceeding the characteristics of the quantum dots and the colloidal quantum dots of the ternary compound semiconductor shown in Non-Patent Document 2. Specifically, particularly in the short wavelength region, the influence of the difference in particle size on the change in the emission wavelength becomes small, the emission wavelength can be precisely controlled, and good chromaticity is realized. In addition, the full width at half maximum (FWHM) of the emission spectrum is narrowed, and the color purity is improved. In addition, the Stokes shift is reduced and energy loss is reduced. In all items, the characteristics are improved to the same level as the CdSe colloidal quantum dots.
　本発明の第２の観点の可視蛍光を発するＣｄを含まないコロイダル量子ドットでは、Ｂ２サイトをＳｅにして、Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットにすることにより、可視蛍光を緑色光にすることができる。 In the colloidal quantum dot that does not contain Cd and emits visible fluorescence according to the second aspect of the present invention, the B2 site is changed to Se to form a Zn (Te 1-x , Se x ) colloidal quantum dot, whereby the visible fluorescence is changed to green. Can be light.
　本発明の第３の観点の可視蛍光を発するＣｄを含まないコロイダル量子ドットでは、Ｂ２サイトをＳにして、Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットにすることにより、可視蛍光を赤色光にすることができる。 In the colloidal quantum dot that does not contain Cd and emits visible fluorescence according to the third aspect of the present invention, the visible fluorescence is changed to red by changing the B2 site to S and forming a Zn (Te 1-x , S x ) colloidal quantum dot. Can be light.
　本発明の第４の観点の製造方法では、Ｚｎ、Ｔｅ及びＳｅの各原料液を混合した第１混合液と、キャッピング剤と希釈剤とを混合した第２混合液とを混合して、全元素（Ｚｎ、Ｔｅ、Ｓｅ）を一括調製するため、コロイダル量子ドットのモル組成比をモル仕込比で簡便に制御できる。また温度の高い一方の液に温度の低い他方の液を注入するため、注入後の温度を大きく変化（低下）させることができ、核生成と成長の分離性が向上し、均一性の高いコロイダル量子ドットが得られ、更に、成長した核を一定温度に保持するため、粒径を時間で容易に制御でき、結果として、可視蛍光が緑色光であるＣｄを含まないコロイダル量子ドットが得られる。 In the manufacturing method according to the fourth aspect of the present invention, the first mixed liquid obtained by mixing the raw material liquids of Zn, Te, and Se and the second mixed liquid obtained by mixing the capping agent and the diluent are mixed together. Since the elements (Zn, Te, Se) are collectively prepared, the molar composition ratio of the colloidal quantum dots can be easily controlled by the molar charge ratio. In addition, since the lower temperature liquid is injected into one higher temperature liquid, the temperature after injection can be greatly changed (decreased), the separation between nucleation and growth is improved, and the colloidal is highly uniform. Since quantum dots are obtained and the grown nuclei are kept at a constant temperature, the particle size can be easily controlled with time, and as a result, colloidal quantum dots containing no Cd whose visible fluorescence is green light are obtained.
　本発明の第５の観点の製造方法では、Ｚｎ及びＴｅの各原料液を混合した第３混合液と、Ｓ原料液とキャッピング剤と希釈剤とを混合した第４混合液と用いて、温度の高い一方の液に温度の低い他方の液を注入するため、注入後の温度を大きく変化（低下）させることができ、核生成と成長の分離性が向上し、均一性の高いコロイダル量子ドットが得られ、更に、成長した核を一定温度に保持するため、粒径を時間で容易に制御でき、結果として、可視蛍光が赤色光であるＣｄを含まないコロイダル量子ドットが得られる。 In the manufacturing method according to the fifth aspect of the present invention, the third mixed solution obtained by mixing the respective raw material solutions of Zn and Te, and the fourth mixed solution obtained by mixing the S raw material solution, the capping agent, and the diluent are used. Since the lower temperature of the liquid is injected into the higher temperature of the liquid, the post-injection temperature can be greatly changed (decreased), the separation between nucleation and growth is improved, and colloidal quantum dots with high uniformity Furthermore, since the grown nuclei are kept at a constant temperature, the particle size can be easily controlled by time, and as a result, a colloidal quantum dot containing no Cd whose visible fluorescence is red light is obtained.
粒径が２～１０ｎｍのＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットにおけるＳｅのモル組成比ｘSeに対するバンドギャップのシミュレーション結果を示す図である。FIG. 4 is a diagram showing a simulation result of a band gap with respect to a Se molar composition ratio x Se in a Zn (Te 1-x , Se x ) colloidal quantum dot having a particle diameter of 2 to 10 nm. Ｓｅのモル組成比ｘSeが０．３５のときのＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットにおける粒径に対するバンドギャップのシミュレーション結果を示す図である。Molar ratio x Se of Se is a diagram showing a simulation of the band gap results for the particle size in the Zn (Te 1-x, Se x) colloidal quantum dot when the 0.35. 粒径が２～１０ｎｍのＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットにおけるＳのモル組成比ｘSに対するバンドギャップのシミュレーション結果を示す図である。FIG. 4 is a diagram showing a simulation result of a band gap with respect to a molar composition ratio x S of S in a Zn (Te 1-x , S x ) colloidal quantum dot having a particle diameter of 2 to 10 nm. Ｓのモル組成比ｘSが０．３５のときのＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットにおける粒径に対するバンドギャップのシミュレーション結果を示す図である。It is a figure which shows the simulation result of the band gap with respect to the particle size in Zn (Te1 -x , Sx ) colloidal quantum dot when the molar composition ratio xS of S is 0.35.
　次に本発明を実施するための形態を説明する。 Next, a mode for carrying out the present invention will be described.
［有効質量近似計算を用いた材料設計］
　非特許文献４及び５には、コロイダル量子ドットの光学ギャップの粒径依存性を理論的に予測する計算が報告されている。その中でも、シンプルな表記によって他の手法と同様の結果が得られる有効質量近似計算が便利である。ポテンシャル：Ｖ（ｒ）中にある粒子（質量：ｍ）に対するシュレディンガー方程式は次の式（１）で表わされる。 [Material design using effective mass approximation]
Non-Patent Documents 4 and 5 report calculations for theoretically predicting the particle size dependence of the optical gap of colloidal quantum dots. Among them, effective mass approximation calculation that can obtain the same result as other methods by simple notation is convenient. The Schrödinger equation for particles (mass: m) in potential: V (r) is expressed by the following equation (1).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　ここでは、有限深さの井戸型ポテンシャルにおいて有効質量近似を仮定したモデルによって粒径と光学ギャップの関係式を導出する。閉じ込めポテンシャルは、有限の深さで中心対称Ｖ（ｒ）として、次の式（２）のように表わされる。ただし、球状のコロイダル量子ドットの半径をｒ0としている。 Here, a relational expression between the particle size and the optical gap is derived by a model assuming an effective mass approximation in a well-type potential of a finite depth. The confinement potential is expressed as the following equation (2) as a central symmetry V (r) at a finite depth. However, the radius of the spherical colloidal quantum dot is r 0 .
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
  Ｖ0は次の式（３）のように定義する。 V 0 is defined as the following equation (3).
Figure JPOXMLDOC01-appb-M000003
Figure JPOXMLDOC01-appb-M000003
ここで、ΔＥHOMO-LUMOは、コロイダル量子ドットの表層にキャッピング剤として配位している界面活性剤の最高被占軌道（HOMO：Highest Occupied Molecular Orbital）と最低空軌道（LUMO：Lowest Unoccupied Molecular Orbital）のエネルギー差である。界面活性剤として用いたオレイン酸のΔＥHOMO-LUMOは光吸収スペクトル測定より求めた値：４．３５ｅＶとしている。その他、ＺｎＴｅ、ＺｎＳｅ、ＺｎＳのバルク体のバンドギャップ：Ｅgや電子・正孔の有効質量：ｍe *／ｍ0、ｍh *／ｍ0は次の表１に示す値を用いている。 Here, ΔE HOMO-LUMO is the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of the surfactant coordinated as a capping agent on the surface of the colloidal quantum dot. ) Energy difference. ΔE HOMO-LUMO of oleic acid used as the surfactant is a value obtained by measuring the light absorption spectrum: 4.35 eV. Other, ZnTe, ZnSe, the band gap of the bulk of the ZnS: E g and electron-hole effective mass: m e * / m 0, m h * / m 0 is used the values shown in the following Table 1 .
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　以上より、コロイダル量子ドットの粒径がｒ0の時のバンドギャップ：Ｅが、ＺｎＴｅ、ＺｎＳｅ、ＺｎＳのバルク体のバンドギャップ：Ｅgと電子・正孔の有効質量：ｍe *／ｍ0、ｍh *／ｍ0を用いて求められる。
　混晶系のバルク体におけるバンドギャップは、ボーイングパラメーター（ｂ）を用いて表された次の式（４）及び（５）を用いて計算する。 From the above, when the colloidal quantum dot particle size is r 0 , the band gap: E is the band gap of the bulk body of ZnTe, ZnSe, ZnS: E g and the effective mass of electrons / holes: me * / m 0 , M h * / m 0 .
The band gap in the mixed crystal bulk body is calculated using the following equations (4) and (5) expressed using the bowing parameter (b).
Figure JPOXMLDOC01-appb-M000005
Figure JPOXMLDOC01-appb-M000005
　ここで、電子・正孔の有効質量：ｍe *／ｍ0、ｍh *／ｍ0の加成性を仮定して、コロイダル量子ドットのバンドギャップと粒径・モル組成比の関係を計算している。例えば、Ｚｎ（Ｔｅ1-x，Ｓｅx）の電子の有効質量の加成性は次の式（６）のように表わされる。 Here, the electron-hole effective mass: m e * / m 0, m h * / the additive property assuming the m 0, calculating the relationship between the band gap and the particle size-molar ratio of the colloidal quantum dots is doing. For example, the additivity of the effective mass of electrons of Zn (Te 1-x , Se x ) is expressed by the following formula (6).
Figure JPOXMLDOC01-appb-M000006
Figure JPOXMLDOC01-appb-M000006
　上記式（１）～（６）に基づいて、粒径が２～１０ｎｍのＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットにおけるＳｅのモル組成比ｘSeに対するバンドギャップのシミュレーション結果を図１に示す。Ｓｅのモル組成比ｘSeと粒径を適切に制御することで、光学ギャップ：２．１～３．４ｅＶの範囲内の、所望のエネルギー値、言い換えると、所望の発光色を実現できる。また、Ｓｅのモル組成比ｘSeが０．３５のときのＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットにおける粒径に対するバンドギャップのシミュレーション結果を図２に示す。帯の部分が緑色発光領域を示している。一般的に１００ｍｅＶであるストークスシフトを考慮して、Ｓｅのモル組成比ｘSeと粒径を調整することで、Ｃｄを含まないＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットにて緑色発光が実現できる。また、粒径が２～１０ｎｍのＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットにおけるＳのモル組成比ｘSに対するバンドギャップのシミュレーション結果を図３に示す。Ｓのモル組成比ｘSと粒径を適切に制御することで、光学ギャップ：１．９～４．０ｅＶの範囲内の、所望のエネルギー値、言い換えると、所望の発光色を実現できる。更に、Ｓのモル組成比ｘSが０．３５のときのＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットにおける粒径に対するバンドギャップのシミュレーション結果を図４に示す。帯の部分が赤色発光領域を示している。一般的に１００ｍｅＶであるストークスシフトを考慮して、Ｓのモル組成比ｘSと粒径を調整することで、Ｃｄを含まないＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットにて赤色発光が実現できる。 Based on the above formulas (1) to (6), the simulation results of the band gap with respect to the molar composition ratio x Se of Se in Zn (Te 1-x , Se x ) colloidal quantum dots having a particle size of 2 to 10 nm are shown in FIG. Shown in By appropriately controlling the Se molar composition ratio x Se and the particle size, it is possible to realize a desired energy value, in other words, a desired emission color, within the optical gap range of 2.1 to 3.4 eV. FIG. 2 shows a simulation result of the band gap with respect to the particle diameter in the Zn (Te 1-x , Se x ) colloidal quantum dot when the Se molar composition ratio x Se is 0.35. The band portion indicates the green light emitting region. Considering the Stokes shift, which is typically 100 meV, by adjusting the Se molar composition ratio x Se and the particle size, green light is emitted from Zn (Te 1-x , Se x ) colloidal quantum dots that do not contain Cd. Can be realized. FIG. 3 shows the simulation results of the band gap with respect to the molar composition ratio x S of S in Zn (Te 1-x , S x ) colloidal quantum dots having a particle diameter of 2 to 10 nm. By appropriately controlling the molar composition ratio x S of S and the particle diameter, a desired energy value in the range of 1.9 to 4.0 eV, in other words, a desired emission color can be realized. Furthermore, FIG. 4 shows a simulation result of the band gap with respect to the particle diameter in a Zn (Te 1-x , S x ) colloidal quantum dot when the molar composition ratio x S of S is 0.35. A band portion indicates a red light emitting region. Taking into account the Stokes shift, which is typically 100 meV, red light is emitted from Zn (Te 1-x , S x ) colloidal quantum dots that do not contain Cd by adjusting the molar composition ratio x S of S and the particle size. Can be realized.
［本実施形態のコロイダル量子ドット］
　本実施形態のコロイダル量子ドットは、化合物半導体からなるシェルで被覆され、前記シェルのコアをなすコア粒子であって、近紫外領域又は青色領域の波長を有する励起光を照射したときに可視蛍光を発するＣｄを含まないコロイダル量子ドットである。このコロイダル量子ドットは、化学式Ａ（Ｂ１1-x，Ｂ２x）（ただし、０＜ｘ＜１）で表され、ＡサイトにII族元素としてのＺｎを、Ｂ１サイトにVI族元素としてのＴｅを、Ｂ２サイトにVI族元素としてのＳｅ又はＳをそれぞれ有し、平均粒径が１ｎｍ以上１０ｎｍ以下であることを特徴とする。ここで、ｘが０＜ｘ＜１であるのは、ｘ＝０であると、ＺｎＴｅとなり、また、ｘ＝１であると、ＺｎＳｅ又はＺｎＳとなり、それぞれ本発明の目的・効果を奏しないからである。また、平均粒径が１ｎｍ未満であると、粒径制御が困難になり、１０ｎｍを超えると、粒成長に非常に長い時間を要し、生産効率が悪くなるとともに、粒度分布が広くなり、色純度が悪くなる。 [Colloidal quantum dots of this embodiment]
The colloidal quantum dot of this embodiment is a core particle that is coated with a shell made of a compound semiconductor and forms the core of the shell, and emits visible fluorescence when irradiated with excitation light having a wavelength in the near ultraviolet region or blue region. It is a colloidal quantum dot that does not contain emitted Cd. This colloidal quantum dot is represented by the chemical formula A (B1 1-x , B2 x ) (where 0 <x <1), Zn as a group II element at the A site, and Te as a group VI element at the B1 site. The B2 site has Se or S as a group VI element, and has an average particle size of 1 nm or more and 10 nm or less. Here, x is 0 <x <1 because when x = 0, it becomes ZnTe, and when x = 1, it becomes ZnSe or ZnS, which does not have the object and effect of the present invention. It is. Further, if the average particle size is less than 1 nm, it is difficult to control the particle size, and if it exceeds 10 nm, it takes a very long time for grain growth, resulting in poor production efficiency, widening the particle size distribution, and color. Purity deteriorates.
　等電子トラップの概念は１９６５年にＴｈｏｍａｓらにより提案された。等電子トラップとは、化合物半導体を構成している元素（例えば、ＺｎとＴｅ）と同じ電子配置をもつ元素（Ｓｅ）を微量に添加し、格子点を置換させると、母体元素（Ｔｅ）との電子親和力の相違のために、電子又は正孔が引き付けられ、束縛状態となるものをいう。等電子トラップによる発光機構は、格子の変位とエネルギーの関係を示す配位座標モデルを用いて説明できる。励起状態にある励起子が、束縛されることによってできた励起状態のポテンシャルのくぼみにトラップされる。くぼみに入ることで、基底状態のポテンシャルとの差が小さくなる。従って、くぼみの準位と基底状態との間の遷移は、元々の化合物半導体（ＺｎＴｅ）が持つバンドギャップよりも小さいエネルギーでの発光となる。 The concept of isoelectronic trap was proposed in 1965 by Thomas et al. An isoelectron trap is obtained by adding a small amount of an element (Se) having the same electron configuration as an element constituting a compound semiconductor (for example, Zn and Te) and substituting a lattice point, This means that electrons or holes are attracted and become bound due to the difference in electron affinity. The light emission mechanism by the isoelectronic trap can be explained by using a coordinate coordinate model indicating the relationship between the lattice displacement and the energy. The excitons in the excited state are trapped in the pit of the excited state potential created by being bound. By entering the depression, the difference from the ground state potential is reduced. Therefore, the transition between the level of the dent and the ground state results in light emission with energy smaller than the band gap of the original compound semiconductor (ZnTe).
　上記化学式Ａ（Ｂ１1-x，Ｂ２x）において、Ｂ２サイトをＳｅにすると、Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットとなり、等電子トラップにより、Ｓｅのモル組成比を変量すると、励起子がトラップされる励起状態のポテンシャルのくぼみと、基底状態のポテンシャルとの差が変化し、この元素の組み合せの場合、あるモル組成比にて、可視蛍光を緑色光にすることができる。また、上記化学式Ａ（Ｂ１1-x，Ｂ２x）において、Ｂ２サイトをＳにすると、Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットとなり、前記と同様の機構にて、Ｓのモル組成比を変量すると、励起子がトラップされる励起状態のポテンシャルのくぼみと、基底状態のポテンシャルとの差が変化し、この元素の組み合せの場合、あるモル組成比にて、可視蛍光を赤色光にすることができる。 In the above chemical formula A (B1 1-x , B2 x ), when the B2 site is set to Se, a Zn (Te 1-x , Se x ) colloidal quantum dot is obtained, and when the molar composition ratio of Se is varied by an isoelectronic trap, The difference between the pit of the excited state potential where the exciton is trapped and the potential of the ground state changes, and in the case of a combination of these elements, the visible fluorescence can be changed to green light at a certain molar composition ratio. In the above chemical formula A (B1 1-x , B2 x ), when the B2 site is set to S, it becomes a Zn (Te 1-x , S x ) colloidal quantum dot. When the ratio is varied, the difference between the excited-state potential indentation where the exciton is trapped and the ground-state potential changes. In this combination of elements, visible fluorescence is converted to red light at a certain molar composition ratio. can do.
　本発明のコロイダル量子ドットの製造方法として、次に、第１の実施形態として、可視蛍光が緑色光であるＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットの製造方法を、第２の実施形態として、可視蛍光が赤色光であるＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットの製造方法を、それぞれ詳述する。 Next, as a method for producing a colloidal quantum dot of the present invention, as a first embodiment, a method for producing a Zn (Te 1-x , Se x ) colloidal quantum dot whose visible fluorescence is green light is described as a second embodiment. As a form, the manufacturing method of Zn (Te1 -x , Sx ) colloidal quantum dot whose visible fluorescence is red light is each explained in full detail.
＜第１の実施形態＞
〔可視蛍光が緑色光であるＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットの製造方法〕
　第１の実施形態の緑色光を発するコロイダル量子ドットの製造方法は、Ｚｎ原料液とＴｅ原料液とＳｅ原料液とを混合して調製された液又はキャッピング剤と希釈剤とを混合して調製された液のいずれか一方の液を２００℃～３５０℃の温度に加熱し、前記加熱した一方の液に前記いずれか他方の液を非酸化性雰囲気下で所定量注入し、前記一方の液に前記他方の液を注入した液を２００℃～３５０℃の温度に調整し、１分～５時間保持することにより、可視蛍光が緑色光であるＣｄを含まないコロイダル量子ドットを製造する方法である。 <First Embodiment>
[Method for producing Zn (Te 1-x , Se x ) colloidal quantum dots whose visible fluorescence is green light]
The method for producing a colloidal quantum dot that emits green light according to the first embodiment is prepared by mixing a liquid prepared by mixing a Zn raw material liquid, a Te raw material liquid, and a Se raw material liquid, or a capping agent and a diluent. One of the two liquids is heated to a temperature of 200 ° C. to 350 ° C., and a predetermined amount of the other liquid is injected into the heated one liquid in a non-oxidizing atmosphere. The liquid into which the other liquid was injected was adjusted to a temperature of 200 ° C. to 350 ° C. and held for 1 minute to 5 hours, thereby producing a colloidal quantum dot containing no Cd whose visible fluorescence is green light. is there.
　この第１の実施形態の製造方法は、一例を挙げると、（a）Ｚｎ原料液とＴｅ原料液とＳｅ原料液とを混合して、第１混合液を調製する工程と、（b）密閉容器にキャッピング剤と希釈剤を入れて混合して、第２混合液を調製する工程と、（c）前記第２混合液の温度を２００℃～３５０℃に調整し、かつ前記密閉容器内を非酸化性雰囲気にした状態で、前記第２混合液に前記第１混合液を所定量注入する工程と、（d）前記第２混合液に前記第１混合液を注入した液の温度を２００℃～３５０℃に調整し、１分～５時間保持する工程と、を含む。ここで、第２混合液の温度を２００℃～３５０℃に調整するのは、２００℃未満では、素早い核生成が起こらず、粒度分布が広くなるからであり、また、３５０℃を超えると、有機溶媒の揮発が優先的に生じ、コロイダル量子ドットの生成に支障をきたすからである。好ましい第２混合液の調整温度は２５０℃～３１０℃である。また、第２混合液に前記第１混合液を注入した液の温度を２００℃～３５０℃にするのは、２００℃未満では、コロイドの成長速度が非常に遅くなり、時間による粒径制御が極めて困難になるからであり、３５０℃を超えると、有機溶媒の揮発が優先的に生じ、コロイダル量子ドットの成長に支障をきたすからである。好ましい保持温度は２３０℃～３００℃である。更に、第２混合液に前記第１混合液を注入した液の保持時間を１分～５時間にするのは、１分未満では、原料が殆ど消費されず、収率が大きく低減するからであり、５時間を超えると、生産性が悪く、成長時の加熱時に消費される電力のコストが大きく増加するからである。好ましい保持時間は１０分～６０分である。 An example of the manufacturing method of the first embodiment is as follows: (a) a step of mixing a Zn raw material liquid, a Te raw material liquid, and a Se raw material liquid to prepare a first mixed liquid; and (b) sealing. (C) adjusting the temperature of the second mixed liquid to 200 ° C. to 350 ° C., and adding the capping agent and diluent to the container and mixing them; In a non-oxidizing atmosphere, a step of injecting a predetermined amount of the first mixture into the second mixture; and (d) a temperature of the solution obtained by injecting the first mixture into the second mixture is 200. And a step of adjusting to a temperature of from 350 to 350 ° C. and holding for 1 minute to 5 hours. Here, the reason why the temperature of the second mixed solution is adjusted to 200 ° C. to 350 ° C. is that if it is less than 200 ° C., rapid nucleation does not occur and the particle size distribution becomes wide, and if it exceeds 350 ° C., This is because volatilization of the organic solvent occurs preferentially and hinders the production of colloidal quantum dots. The adjustment temperature of the second liquid mixture is preferably 250 ° C. to 310 ° C. In addition, the temperature of the liquid obtained by injecting the first mixed liquid into the second mixed liquid is set to 200 ° C. to 350 ° C. If the temperature is lower than 200 ° C., the growth rate of the colloid becomes very slow, and the particle size can be controlled by time. This is because when the temperature exceeds 350 ° C., the volatilization of the organic solvent occurs preferentially, which hinders the growth of colloidal quantum dots. A preferred holding temperature is 230 ° C to 300 ° C. Furthermore, the retention time of the liquid obtained by injecting the first mixed liquid into the second mixed liquid is set to 1 minute to 5 hours because the raw material is hardly consumed and the yield is greatly reduced if it is less than 1 minute. Yes, if it exceeds 5 hours, the productivity is poor, and the cost of power consumed during heating during growth greatly increases. The preferred holding time is 10 minutes to 60 minutes.
〔Ｚｎ原料液の調製〕
　Ｚｎ原料液は、不活性ガスで置換した容器内に、Ｚｎ源としての液状のジエチル亜鉛（ＤＥＺ）又は粉末状のステアリン酸亜鉛（Ｚｎ（Ｓｔ）2）等を入れ、これに、トリオクチルホスフィン（ＴＯＰ）、オクタデセン（ＯＤＥ）、酢酸、オレイン酸（ＯＡ）、ステアリン酸、ヘキサデシルアミン（ＨＤＡ）、オレイルアミン（ＯＬＡ）、トリオクチルアミン（ＴＯＡ）、トリブチルホスホン酸（ＴＢＰＡ）等の有機溶媒（錯形成剤）を加えて、加熱することにより調製される。なお、Ｚｎイオンと錯体を形成する有機溶媒であれば、上述の有機溶媒に限定されるものではない。不活性ガスを通気しながら、Ｚｎ原料の混合液が入った容器をオイルバス等で加熱する。オイルバスで加熱する温度は２０℃～３５０℃であり、加熱した温度での保持時間は５分～５時間である。加熱温度が２０℃未満又は保持時間が５分未満では、Ｚｎ源の有機溶媒（錯形成剤）への溶解が十分でなく、Ｚｎ源の未溶解分が発生しやすい。また、加熱温度が３５０℃を超えると、有機溶媒（錯形成剤）の揮発が優先的に生じ、Ｚｎ源の溶解に支障をきたす。保持時間が５時間を超えると、Ｚｎ源は十分に溶解平衡に達しており、加熱による無駄な電力消費が発生する。Ｚｎ源１ｍｏｌに対して有機溶媒（錯形成剤）を１～１６ｍｏｌ加える。Ｚｎ原料が溶解すると、混合液が透明になる。なお、Ｚｎ原料液の調製は、上記の調製条件に限定されるものではなく、用いる錯体形成用溶媒との組み合わせに応じて条件を調整することができる。 [Preparation of Zn raw material solution]
In the Zn raw material solution, liquid diethylzinc (DEZ) or powdered zinc stearate (Zn (St) 2 ) or the like as a Zn source is placed in a container substituted with an inert gas, and trioctylphosphine is added thereto. Organic solvents such as (TOP), octadecene (ODE), acetic acid, oleic acid (OA), stearic acid, hexadecylamine (HDA), oleylamine (OLA), trioctylamine (TOA), tributylphosphonic acid (TBPA) It is prepared by adding a complexing agent) and heating. Note that the organic solvent is not limited to the organic solvents described above as long as the organic solvent forms a complex with Zn ions. While venting inert gas, the container containing the mixed solution of Zn raw material is heated with an oil bath or the like. The temperature heated in the oil bath is 20 ° C. to 350 ° C., and the holding time at the heated temperature is 5 minutes to 5 hours. When the heating temperature is less than 20 ° C. or the holding time is less than 5 minutes, the Zn source is not sufficiently dissolved in the organic solvent (complexing agent), and an undissolved portion of the Zn source is likely to be generated. On the other hand, if the heating temperature exceeds 350 ° C., volatilization of the organic solvent (complexing agent) occurs preferentially, which hinders dissolution of the Zn source. When the holding time exceeds 5 hours, the Zn source has sufficiently reached dissolution equilibrium, and wasteful power consumption due to heating occurs. 1 to 16 mol of an organic solvent (complexing agent) is added to 1 mol of Zn source. When the Zn raw material is dissolved, the mixed solution becomes transparent. In addition, preparation of Zn raw material liquid is not limited to said preparation conditions, Conditions can be adjusted according to the combination with the solvent for complex formation to be used.
〔Ｔｅ原料液の調製〕
　Ｔｅ原料液は、不活性ガスで置換した容器内に、Ｔｅ源としての粉末状の金属テルル（Ｔｅ）、粉末状の酸化テルル又は入手可能な安価で安全な有機テルル化合物等を入れ、これに、Ｚｎ原料液の調製に用いたのと同様の有機溶媒（錯形成剤）を加えて、加熱することにより調製される。なお、Ｔｅイオンと錯体を形成する有機溶媒であれば、上述の有機溶媒に限定されるものではない。不活性ガスを通気しながら、Ｔｅ原料の混合液が入った容器をオイルバス等で加熱する。オイルバスで加熱する温度は１００℃～３５０℃であり、加熱した温度での保持時間は５分～５時間である。加熱温度が１００℃未満又は保持時間が５分未満では、Ｔｅ源の有機溶媒（錯形成剤）への溶解が十分でなく、Ｔｅ源の未溶解分が発生しやすい。また、加熱温度が３５０℃を超えると、有機溶媒（錯形成剤）の揮発が優先的に生じ、Ｔｅ源の溶解に支障をきたす。保持時間が５時間を超えると、Ｔｅ源は十分に溶解平衡に達しており、加熱による無駄な電力消費が発生する。 [Preparation of Te raw material liquid]
The Te raw material liquid is filled with powdered metal tellurium (Te) as a Te source, powdered tellurium oxide or an available inexpensive and safe organic tellurium compound in a container substituted with an inert gas. The same organic solvent (complex forming agent) as used for the preparation of the Zn raw material solution is added and heated. Note that the organic solvent is not limited to the organic solvents described above as long as the organic solvent forms a complex with Te ions. While ventilating the inert gas, the container containing the Te raw material mixture is heated in an oil bath or the like. The temperature at which the oil bath is heated is 100 ° C. to 350 ° C., and the holding time at the heated temperature is 5 minutes to 5 hours. When the heating temperature is less than 100 ° C. or the holding time is less than 5 minutes, the Te source is not sufficiently dissolved in the organic solvent (complexing agent), and an undissolved portion of the Te source is likely to be generated. On the other hand, when the heating temperature exceeds 350 ° C., volatilization of the organic solvent (complex forming agent) occurs preferentially, which hinders dissolution of the Te source. When the holding time exceeds 5 hours, the Te source has sufficiently reached dissolution equilibrium, and wasteful power consumption due to heating occurs.
〔Ｓｅ原料液の調製〕
　Ｓｅ原料液は、不活性ガスで置換した容器内に、Ｓｅ源としての粉末状の金属セレン（Ｓｅ）、粉末状の酸化セレン又は入手可能な安価で安全な有機セレン化合物等を入れ、これに、Ｚｎ原料液の調製に用いたのと同様の有機溶媒（錯形成剤）を加えて、加熱することにより調製される。なお、Ｓｅイオンと錯体を形成する有機溶媒であれば、上述の有機溶媒に限定されるものではない。不活性ガスを通気しながら、Ｓｅ原料の混合液が入った容器をオイルバス等で加熱する。オイルバスで加熱する温度は２０℃～３５０℃であり、加熱した温度での保持時間は５分～５時間である。加熱温度が２０℃未満又は保持時間が５分未満では、Ｓｅ源の有機溶媒（錯形成剤）への溶解が十分でなく、Ｓｅ源の未溶解分が発生しやすい。また、加熱温度が３５０℃を超えると、有機溶媒（錯形成剤）の揮発が優先的に生じ、Ｓｅ源の溶解に支障をきたす。保持時間が５時間を超えると、Ｓｅ源は十分に溶解平衡に達しており、加熱による無駄な電力消費が発生する。Ｓｅ源１ｍｏｌに対して有機溶媒（錯形成剤）を１～１０ｍｏｌ加える。Ｓｅ原料が溶解すると、混合液が透明になる。なお、Ｓｅ原料液の調製は、上記の調製条件に限定されるものではなく、用いる錯体形成用溶媒との組み合わせに応じて条件を調整することができる。 [Preparation of Se raw material liquid]
The Se raw material liquid is filled with powdered metal selenium (Se) as a Se source, powdered selenium oxide or an available inexpensive and safe organic selenium compound in a container substituted with an inert gas. The same organic solvent (complex forming agent) as used for the preparation of the Zn raw material solution is added and heated. Note that the organic solvent is not limited to the organic solvents described above as long as the organic solvent forms a complex with Se ions. While ventilating the inert gas, the container containing the Se raw material mixture is heated in an oil bath or the like. The temperature heated in the oil bath is 20 ° C. to 350 ° C., and the holding time at the heated temperature is 5 minutes to 5 hours. When the heating temperature is less than 20 ° C. or the holding time is less than 5 minutes, the Se source is not sufficiently dissolved in the organic solvent (complexing agent), and the Se source is not easily dissolved. On the other hand, if the heating temperature exceeds 350 ° C., the organic solvent (complexing agent) volatilizes preferentially, which hinders dissolution of the Se source. When the holding time exceeds 5 hours, the Se source has sufficiently reached dissolution equilibrium, and wasteful power consumption due to heating occurs. 1 to 10 mol of an organic solvent (complexing agent) is added to 1 mol of Se source. When the Se raw material is dissolved, the mixed solution becomes transparent. In addition, preparation of Se raw material liquid is not limited to said preparation conditions, Conditions can be adjusted according to the combination with the solvent for complex formation to be used.
〔Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドット作製用の第１混合液の調製〕
　第１混合液は、不活性ガスで置換した容器内に、Ｚｎ原料液とＴｅ原料液とＳｅ原料液を所定のモル組成比になるように混合し、室温にて不活性ガスを通気しながら撹拌して調製される。 [Preparation of first mixed solution for preparing Zn (Te 1-x , Se x ) colloidal quantum dots]
The first mixed liquid is a mixture of a Zn raw material liquid, a Te raw material liquid, and a Se raw material liquid in a container substituted with an inert gas so as to have a predetermined molar composition ratio. Prepared with stirring.
〔Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドット作製用の第２混合液の調製〕
　第２混合液は、容器内にキャッピング剤と希釈剤を混合し、撹拌しながら真空中で「１２０℃×３０分間」の脱気処理を行った後、不活性ガスにて大気圧に戻し、不活性ガスを通気しながら、マントルヒーター等を用いて２００℃～３５０℃に昇温し調製される。キャッピング剤としては、トリオクチルホスフィン（ＴＯＰ）、オレイン酸（ＯＡ）、ステアリン酸、ヘキサデシルアミン（ＨＤＡ）、オレイルアミン（ＯＬＡ）、トリブチルホスホン酸（ＴＢＰＡ）、トリオクチルホスフィンオキシド（ＴＯＰＯ）等が挙げられる。希釈剤としては、トリオクチルホスフィン（ＴＯＰ）、オクタデセン（ＯＤＥ）、オレイルアミン（ＯＬＡ）、ヘキサデシルアミン（ＨＤＡ）、トリオクチルホスフィンオキシド（ＴＯＰＯ）等が挙げられる。キャッピング剤１ｍｏｌに対して希釈剤を１～５ｍｏｌ加える。 [Preparation of second mixed solution for preparing Zn (Te 1-x , Se x ) colloidal quantum dots]
The second mixed liquid is a mixture of a capping agent and a diluent in a container, and after performing a degassing process of “120 ° C. × 30 minutes” in a vacuum while stirring, it is returned to atmospheric pressure with an inert gas, It is prepared by raising the temperature to 200 ° C. to 350 ° C. using a mantle heater or the like while ventilating an inert gas. Examples of the capping agent include trioctylphosphine (TOP), oleic acid (OA), stearic acid, hexadecylamine (HDA), oleylamine (OLA), tributylphosphonic acid (TBPA), trioctylphosphine oxide (TOPO) and the like. It is done. Examples of the diluent include trioctylphosphine (TOP), octadecene (ODE), oleylamine (OLA), hexadecylamine (HDA), and trioctylphosphine oxide (TOPO). Add 1-5 mol of diluent to 1 mol of capping agent.
〔第２混合液の第１混合液への注入〕
　マントルヒーター等を用いて２００℃～３５０℃に昇温した第２混合液の温度が安定した後、第１混合液（室温）をシリンジ等を用いて第２混合液へ一気に注入し、コロイダル量子ドットの核を生成させる。具体的には、内径１０ｍｍのシリンジを用いて１～２０ｍＬ／秒の押し込み速度で注入する。下限値未満の速度でゆっくり注入すると、経時的に核が生成するため、粒度分布が広くなる。上限値を超えた高速度では注入操作が技術的に困難になる。これにより、Ｚｎ原料液とＴｅ原料液とＳｅ原料液の混合液が調製される。第１混合液を第２混合液へ混合する方法として、混合の規模によっては、不活性圧縮ガスを利用して、ノズル混合、エジェクター混合等の混合方法を採用してもよい。ここで、第２混合液の温度を２００℃～３５０℃に調整するのは、２００℃未満では、素早い核生成が起こらず、粒度分布が広くなるからであり、また、３５０℃を超えると、有機溶媒の揮発が優先的に生じ、コロイダル量子ドットの核生成に支障をきたすからである。 [Injection of the second liquid mixture into the first liquid mixture]
After the temperature of the second mixed liquid heated to 200 ° C. to 350 ° C. using a mantle heater or the like is stabilized, the first mixed liquid (room temperature) is injected into the second mixed liquid at once using a syringe or the like, and colloidal quantum Generate dot nuclei. Specifically, the injection is performed at a pushing speed of 1 to 20 mL / second using a syringe having an inner diameter of 10 mm. When slowly injected at a rate less than the lower limit, nuclei are formed over time, and the particle size distribution becomes wide. At high speeds above the upper limit, the injection operation becomes technically difficult. Thereby, the liquid mixture of Zn raw material liquid, Te raw material liquid, and Se raw material liquid is prepared. As a method of mixing the first mixed solution into the second mixed solution, a mixing method such as nozzle mixing or ejector mixing may be employed using an inert compressed gas depending on the scale of mixing. Here, the reason why the temperature of the second mixed solution is adjusted to 200 ° C. to 350 ° C. is that if it is less than 200 ° C., rapid nucleation does not occur and the particle size distribution becomes wide, and if it exceeds 350 ° C., This is because volatilization of the organic solvent occurs preferentially and hinders the nucleation of colloidal quantum dots.
〔注入後の核成長〕
　第１混合液（室温）をシリンジ等を用いて第２混合液へ一気に注入した後、速やかに溶液の温度が低下する。溶液の温度を２００℃～３５０℃で１分～５時間保持して、コロイダル量子ドットを成長させる。所定時間保持した後、室温まで放冷する。反応溶液は濁りのない透明な溶液になる。ここで、２００℃未満では、コロイドの成長速度が非常に遅くなり、時間による粒径制御が極めて困難になり、３５０℃を超えると、有機溶媒の揮発が優先的に生じ、コロイダル量子ドットの成長に支障をきたす。また、１分未満では、原料が殆ど消費されず、収率が大きく低減し、５時間を超えると、生産性が悪く、成長時の加熱時に消費される電力のコストが大きく増加する。 [Nuclear growth after implantation]
After inject | pouring a 1st liquid mixture (room temperature) at a stretch into a 2nd liquid mixture using a syringe etc., the temperature of a solution falls quickly. The temperature of the solution is maintained at 200 ° C. to 350 ° C. for 1 minute to 5 hours to grow colloidal quantum dots. After holding for a predetermined time, it is allowed to cool to room temperature. The reaction solution becomes a clear solution without turbidity. Here, when the temperature is lower than 200 ° C., the growth rate of the colloid becomes very slow and it becomes extremely difficult to control the particle size by time. When the temperature exceeds 350 ° C., the organic solvent volatilizes preferentially, and the growth of colloidal quantum dots Cause trouble. When the time is less than 1 minute, almost no raw material is consumed and the yield is greatly reduced. When the time is longer than 5 hours, the productivity is poor and the cost of power consumed during heating during growth is greatly increased.
　第２混合液の温度、第１混合液を第２混合液へ注入した後の溶液の温度と保持時間を調整することで、得られるコロイダル量子ドットの平均粒径を一定にすることができる。このようにして平均粒径を４．０±０．１ｎｍに調整した場合、第１混合液中のＳｅのモル仕込比ｘSeを変えると、即ち、コロイダル量子ドットのＳｅのモル組成比ｘSeを変えると、バンドギャップボーイング効果が観察され、ｘSe＝０．３０付近でバンドギャップの値が最小値：約２．４ｅＶを示す。次に、Ｓｅのモル組成比ｘSeを０．３０付近で固定した場合、第２混合液の温度、第１混合液を第２混合液へ注入した後の溶液の温度と保持時間を調整することで、コロイダル量子ドットの平均粒径を３．０～７．０ｎｍの範囲で調整できる。量子サイズ効果によりコロイダル量子ドットのバンドギャップが変化し、平均粒径が３．０～７．０ｎｍの領域で緑色発光（２．１５～２．４５ｅＶ）が実現する。 By adjusting the temperature of the second mixed liquid, the temperature of the solution after the first mixed liquid is injected into the second mixed liquid, and the holding time, the average particle size of the obtained colloidal quantum dots can be made constant. When the average particle size is adjusted to 4.0 ± 0.1 nm in this way, changing the Se molar charge ratio x Se in the first mixed solution, that is, the molar composition ratio x Se of colloidal quantum dots Se. , The band gap bowing effect is observed, and the value of the band gap is about 2.4 eV in the vicinity of x Se = 0.30. Next, when the Se molar composition ratio x Se is fixed at around 0.30, the temperature of the second mixed solution, the temperature of the solution after the first mixed solution is injected into the second mixed solution, and the holding time are adjusted. Thus, the average particle size of the colloidal quantum dots can be adjusted in the range of 3.0 to 7.0 nm. The band gap of the colloidal quantum dots changes due to the quantum size effect, and green light emission (2.15 to 2.45 eV) is realized in the region where the average particle size is 3.0 to 7.0 nm.
＜第２の実施形態＞
〔可視蛍光が赤色光であるＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットの製造方法〕
　第２の実施形態の赤色光を発するコロイダル量子ドットの製造方法は、Ｚｎ原料液とＴｅ原料液とを混合して調製された液又はＳ原料液とキャッピング剤と希釈剤とを混合して調製された液のいずれか一方の液を２００℃～３５０℃の温度に加熱し、前記加熱した一方の液に前記いずれか他方の液を非酸化性雰囲気下で所定量注入し、前記一方の液に前記他方の液を注入した液を２００℃～３５０℃の温度に調整し、１分～５時間保持することにより、可視蛍光が赤色光であるＣｄを含まないコロイダル量子ドットを製造する方法である。 <Second Embodiment>
[Method for producing Zn (Te 1-x , S x ) colloidal quantum dots whose visible fluorescence is red light]
The method for producing a colloidal quantum dot emitting red light according to the second embodiment is prepared by mixing a Zn raw material liquid and a Te raw material liquid or a S raw material liquid, a capping agent, and a diluent. One of the two liquids is heated to a temperature of 200 ° C. to 350 ° C., and a predetermined amount of the other liquid is injected into the heated one liquid in a non-oxidizing atmosphere. The liquid into which the other liquid was injected was adjusted to a temperature of 200 ° C. to 350 ° C. and held for 1 minute to 5 hours to produce a colloidal quantum dot containing no Cd whose visible fluorescence is red light. is there.
　この第２の実施形態の製造方法は、一例を挙げると、（a）Ｚｎ原料液とＴｅ原料液とを混合して、第３混合液を調製する工程と、（b）密閉容器にＳ原料液とキャッピング剤と希釈剤を混合して、第４混合液を調製する工程と、（c）前記第４混合液の温度を２００℃～３５０℃に調整し、かつ前記密閉容器内を非酸化性雰囲気にした状態で、前記第４混合液に前記第３混合液を所定量注入する工程と、（d）前記第４混合液に前記第３混合液を注入した液の温度を２００℃～３５０℃に調整し、１分～５時間保持する工程と、を含む。ここで、第４混合液の温度を２００℃～３５０℃に調整するのは、２００℃未満では、素早い核生成が起こらず、粒度分布が広くなるからであり、また、３５０℃を超えると、有機溶媒の揮発が優先的に生じ、コロイダル量子ドットの生成に支障をきたすからである。好ましい第４混合液の調整温度は２６０℃～３２０℃である。また、第４混合液に前記第３混合液を注入した液の温度を２００℃～３５０℃にするのは、２００℃未満では、コロイダル量子ドットの成長速度が非常に遅くなり、時間による粒径制御が極めて困難になるからであり、３５０℃を超えると、有機溶媒の揮発が優先的に生じ、コロイダル量子ドットの成長に支障をきたすからである。好ましい保持温度は２４０℃～３１０℃である。更に、第４混合液に前記第３混合液を注入した液の保持時間を１分～５時間にするのは、１分未満では、原料が殆ど消費されず、収率が大きく低減するからであり、５時間を超えると、生産性が悪く、成長時の加熱時に消費される電力のコストが大きく増加するからである。好ましい保持時間は１０分～３時間である。 In the manufacturing method of the second embodiment, for example, (a) a step of mixing a Zn raw material liquid and a Te raw material liquid to prepare a third mixed liquid; and (b) an S raw material in a sealed container. (C) adjusting the temperature of the fourth mixture to 200 ° C. to 350 ° C., and non-oxidizing the inside of the sealed container A step of injecting a predetermined amount of the third mixed liquid into the fourth mixed liquid in a neutral atmosphere; and (d) the temperature of the liquid injected with the third mixed liquid into the fourth mixed liquid is 200 ° C. to Adjusting to 350 ° C. and holding for 1 minute to 5 hours. Here, the reason why the temperature of the fourth mixed liquid is adjusted to 200 ° C. to 350 ° C. is that if it is less than 200 ° C., rapid nucleation does not occur and the particle size distribution becomes wide, and if it exceeds 350 ° C., This is because volatilization of the organic solvent occurs preferentially and hinders the production of colloidal quantum dots. The adjustment temperature of the fourth mixed solution is preferably 260 ° C. to 320 ° C. In addition, the temperature of the liquid obtained by injecting the third mixed liquid into the fourth mixed liquid is set to 200 ° C. to 350 ° C. If the temperature is lower than 200 ° C., the growth rate of the colloidal quantum dots becomes very slow. This is because it becomes extremely difficult to control, and when it exceeds 350 ° C., volatilization of the organic solvent occurs preferentially, which hinders the growth of colloidal quantum dots. A preferred holding temperature is 240 ° C to 310 ° C. Furthermore, the retention time of the liquid obtained by injecting the third mixed liquid into the fourth mixed liquid is set to 1 minute to 5 hours because the raw material is hardly consumed and the yield is greatly reduced if it is less than 1 minute. Yes, if it exceeds 5 hours, the productivity is poor, and the cost of power consumed during heating during growth greatly increases. The preferred holding time is 10 minutes to 3 hours.
〔Ｚｎ原料液の調製〕
　Ｚｎ原料液は、前述したＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットの製造方法で用いたＺｎ原料液と同様に調製される。Ｚｎ源１ｍｏｌに対して有機溶媒（錯形成剤）を１～１６ｍｏｌ加える。Ｚｎ原料が溶解すると、混合液が透明になる。なお、Ｚｎ原料液の調製は、上記の調製条件に限定されるものではなく、用いる錯体形成用溶媒との組み合わせに応じて条件を調整することができる。 [Preparation of Zn raw material solution]
The Zn raw material liquid is prepared in the same manner as the Zn raw material liquid used in the above-described method for producing Zn (Te 1-x , Se x ) colloidal quantum dots. 1 to 16 mol of an organic solvent (complexing agent) is added to 1 mol of Zn source. When the Zn raw material is dissolved, the mixed solution becomes transparent. In addition, preparation of Zn raw material liquid is not limited to said preparation conditions, Conditions can be adjusted according to the combination with the solvent for complex formation to be used.
〔Ｔｅ原料液の調製〕
　Ｔｅ原料液は、前述したＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットの製造方法で用いたＴｅ原料液と同様に調製される。 [Preparation of Te raw material liquid]
The Te raw material liquid is prepared in the same manner as the Te raw material liquid used in the above-described method for producing Zn (Te 1-x , Se x ) colloidal quantum dots.
〔Ｓ原料液の調製〕
　Ｓ原料液は、不活性ガスで置換した容器内に、Ｓ源としての粉末状の硫黄（Ｓ）又は入手可能な安価で安全な有機硫黄化合物等を入れ、これに、Ｚｎ原料液の調製に用いたのと同様の有機溶媒（錯形成剤）を加えて、加熱することにより調製される。なお、Ｓイオンと錯体を形成する有機溶媒であれば、上述の有機溶媒に限定されるものではない。不活性ガスを通気しながら、Ｓ原料の混合液が入った容器をオイルバス等で加熱する。オイルバスで加熱する温度は２０℃～３５０℃であり、加熱した温度での保持時間は５分～５時間である。加熱温度が２０℃未満又は保持時間が５分未満では、Ｓ源の有機溶媒（錯形成剤）への溶解が十分でなく、Ｓ源の未溶解分が発生しやすい。また、加熱温度が３５０℃を超えると、有機溶媒（錯形成剤）の揮発が優先的に生じ、Ｓ源の溶解に支障をきたす。保持時間が５時間を超えると、Ｓ源は十分に溶解平衡に達しており、加熱による無駄な電力消費が発生する。Ｓ源１ｍｏｌに対して有機溶媒（錯形成剤）を１～１０ｍｏｌ加える。Ｓ原料が溶解すると、混合液が透明になる。なお、Ｓ原料液の調製は、上記の調製条件に限定されるものではなく、用いる錯体形成用溶媒との組み合わせに応じて条件を調整することができる。 [Preparation of S raw material solution]
The S raw material liquid is filled with powdered sulfur (S) as an S source or an available inexpensive and safe organic sulfur compound in a container substituted with an inert gas. It is prepared by adding the same organic solvent (complexing agent) as used and heating. Note that the organic solvent is not limited to the organic solvents described above as long as the organic solvent forms a complex with S ions. While ventilating the inert gas, the container containing the mixed solution of the S raw material is heated with an oil bath or the like. The temperature heated in the oil bath is 20 ° C. to 350 ° C., and the holding time at the heated temperature is 5 minutes to 5 hours. When the heating temperature is less than 20 ° C. or the holding time is less than 5 minutes, the S source is not sufficiently dissolved in the organic solvent (complexing agent), and an undissolved portion of the S source is likely to be generated. On the other hand, when the heating temperature exceeds 350 ° C., the volatilization of the organic solvent (complexing agent) occurs preferentially, which hinders dissolution of the S source. When the holding time exceeds 5 hours, the S source has sufficiently reached dissolution equilibrium, and wasteful power consumption due to heating occurs. 1 to 10 mol of an organic solvent (complexing agent) is added to 1 mol of the S source. When the S raw material is dissolved, the mixed solution becomes transparent. In addition, preparation of S raw material liquid is not limited to said preparation conditions, Conditions can be adjusted according to the combination with the solvent for complex formation to be used.
〔Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドット作製用の第３混合液の調製〕
　第３混合液は、不活性ガスで置換した容器内に、Ｚｎ原料液とＴｅ原料液を所定のモル組成比になるように混合し、室温にて不活性ガスを通気しながら撹拌して調製される。 [Preparation of third mixed solution for preparing Zn (Te 1-x , S x ) colloidal quantum dots]
The third liquid mixture is prepared by mixing the Zn raw material liquid and the Te raw material liquid so as to have a predetermined molar composition ratio in a container substituted with an inert gas, and stirring the mixture while venting the inert gas at room temperature. Is done.
〔Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドット作製用の第４混合液の調製〕
　第４混合液は、容器内にＳ原料液とキャッピング剤と希釈剤を混合し、撹拌しながら真空中で「１２０℃×３０分間」の脱気処理を行った後、不活性ガスにて大気圧に戻し、不活性ガスを通気しながら、マントルヒーター等を用いて２００℃～３５０℃に昇温し調製される。キャッピング剤としては、トリオクチルホスフィン（ＴＯＰ）、オレイン酸（ＯＡ）、ステアリン酸、ヘキサデシルアミン（ＨＤＡ）、オレイルアミン（ＯＬＡ）、トリブチルホスホン酸（ＴＢＰＡ）、トリオクチルホスフィンオキシド（ＴＯＰＯ）等が挙げられる。希釈剤としては、トリオクチルホスフィン（ＴＯＰ）、オクタデセン（ＯＤＥ）、オレイルアミン（ＯＬＡ）、ヘキサデシルアミン（ＨＤＡ）、トリオクチルホスフィンオキシド（ＴＯＰＯ）等が挙げられる。Ｓ源１ｍｏｌに対してキャッピング剤を５～３０ｍｏｌ、希釈剤を１～３０ｍｏｌ加える。 [Preparation of fourth mixed solution for preparing Zn (Te 1-x , S x ) colloidal quantum dots]
The fourth mixed liquid is a mixture of S raw material liquid, capping agent and diluent in a container, and after deaeration treatment at 120 ° C. for 30 minutes in vacuum with stirring, a large amount of inert gas is used. The pressure is adjusted to 200 ° C. to 350 ° C. using a mantle heater or the like while returning to atmospheric pressure and passing an inert gas. Examples of the capping agent include trioctylphosphine (TOP), oleic acid (OA), stearic acid, hexadecylamine (HDA), oleylamine (OLA), tributylphosphonic acid (TBPA), trioctylphosphine oxide (TOPO) and the like. It is done. Examples of the diluent include trioctylphosphine (TOP), octadecene (ODE), oleylamine (OLA), hexadecylamine (HDA), and trioctylphosphine oxide (TOPO). Add 5-30 mol of capping agent and 1-30 mol of diluent to 1 mol of S source.
〔第３混合液の第４混合液への注入〕
　マントルヒーター等を用いて２００℃～３５０℃に昇温した第４混合液の温度が安定したら、第３混合液（室温）をシリンジ等を用いて第４混合液へ一気に注入し、コロイダル量子ドットの核を生成させる。具体的には、内径１０ｍｍのシリンジを用いて１～２０ｍＬ／秒の押し込み速度で注入する。下限値未満の速度でゆっくり注入すると、経時的に核が生成するため、粒度分布が広くなる。上限値を超えた高速度では、注入操作が技術的に困難になる。これにより、Ｚｎ原料液とＴｅ原料液とＳ原料液を混合した合成液が調製される。第３混合液を第４混合液へ混合する方法として、混合の規模によっては、不活性圧縮ガスを利用して、ノズル混合、エジェクター混合等の混合方法を採用してもよい。ここで、第４混合液の温度を２００℃～３５０℃に調整するのは、２００℃未満では、素早い核生成が起こらず、粒度分布が広くなるからであり、また、３５０℃を超えると、有機溶媒の揮発が優先的に生じ、コロイダル量子ドットの生成に支障をきたすからである。 [Injection of the third mixture into the fourth mixture]
When the temperature of the 4th liquid mixture heated to 200 ° C to 350 ° C using a mantle heater or the like stabilizes, the 3rd liquid mixture (room temperature) is injected into the 4th liquid mixture at once using a syringe or the like, and colloidal quantum dots Generate nuclei. Specifically, the injection is performed at a pushing speed of 1 to 20 mL / second using a syringe having an inner diameter of 10 mm. When slowly injected at a rate less than the lower limit, nuclei are formed over time, and the particle size distribution becomes wide. At high speeds above the upper limit, the injection operation becomes technically difficult. Thereby, a synthetic liquid is prepared by mixing the Zn raw material liquid, the Te raw material liquid, and the S raw material liquid. As a method of mixing the third mixed solution into the fourth mixed solution, a mixing method such as nozzle mixing or ejector mixing may be employed using an inert compressed gas depending on the scale of mixing. Here, the reason why the temperature of the fourth mixed liquid is adjusted to 200 ° C. to 350 ° C. is that if it is less than 200 ° C., rapid nucleation does not occur and the particle size distribution becomes wide, and if it exceeds 350 ° C., This is because volatilization of the organic solvent occurs preferentially and hinders the production of colloidal quantum dots.
〔注入後の核成長〕
　第３混合液（室温）をシリンジ等を用いて第４混合液へ一気に注入した後、速やかに溶液の温度が低下する。溶液の温度を２００℃～３５０℃で１分～５時間保持して、コロイダル量子ドットを成長させる。所定時間保持した後、室温まで放冷する。反応溶液は濁りのない透明な溶液になる。ここで、２００℃未満では、コロイダル量子ドットの成長速度が非常に遅くなり、時間による粒径制御が極めて困難になり、３５０℃を超えると、有機溶媒の揮発が優先的に生じ、コロイダル量子ドットの成長に支障をきたす。また、１分未満では、原料が殆ど消費されず、収率が大きく低減し、５時間を超えると、生産性が悪く、成長時の加熱時に消費される電力のコストが大きく増加する。 [Nuclear growth after implantation]
After injecting the third mixed solution (room temperature) into the fourth mixed solution at a stretch using a syringe or the like, the temperature of the solution quickly decreases. The temperature of the solution is maintained at 200 ° C. to 350 ° C. for 1 minute to 5 hours to grow colloidal quantum dots. After holding for a predetermined time, it is allowed to cool to room temperature. The reaction solution becomes a clear solution without turbidity. Here, if the temperature is lower than 200 ° C., the growth rate of the colloidal quantum dots becomes very slow, and it becomes extremely difficult to control the particle size by time. If the temperature exceeds 350 ° C., volatilization of the organic solvent occurs preferentially, and the colloidal quantum dots Will hinder growth. When the time is less than 1 minute, almost no raw material is consumed and the yield is greatly reduced. When the time is longer than 5 hours, the productivity is poor and the cost of power consumed during heating during growth is greatly increased.
　第４混合液の温度、第３混合液を第４混合液へ注入した後の溶液の温度と保持時間を調整することで、得られるコロイダル量子ドットの平均粒径を一定にすることができる。
　このようにして平均粒径を７．０±０．１ｎｍに調整した場合、第４混合液中のＳのモル仕込比ｘSを変えると、即ち、コロイダル量子ドットのＳのモル組成比ｘSを変えると、バンドギャップボーイング効果が観察され、ｘS＝０．３０付近でバンドギャップの値が最小値：２．０ｅＶを示す。次に、コロイダル量子ドットの平均粒径を５．０～９．０ｎｍの範囲で調整することで、量子サイズ効果によりコロイダル量子ドットのバンドギャップが変化し、赤色発光（１．８０～２．１０ｅＶ）が実現する。 By adjusting the temperature of the 4th liquid mixture, the temperature of the solution after inject | pouring a 3rd liquid mixture into a 4th liquid mixture, and holding time, the average particle diameter of the obtained colloidal quantum dot can be made constant.
When the average particle size is adjusted to 7.0 ± 0.1 nm in this way, the molar charge ratio x S of S in the fourth mixed solution is changed, that is, the molar composition ratio x S of the colloidal quantum dots. Is changed, the band gap bowing effect is observed, and the value of the band gap shows a minimum value: 2.0 eV in the vicinity of x S = 0.30. Next, by adjusting the average particle size of the colloidal quantum dots in the range of 5.0 to 9.0 nm, the band gap of the colloidal quantum dots changes due to the quantum size effect, and red light emission (1.80 to 2.10 eV). ) Is realized.
　次に本発明の実施例を比較例とともに詳しく説明する。 Next, examples of the present invention will be described in detail together with comparative examples.
　本発明の実施例及び比較例において使用する原材料は次の通りである。
〔原材料〕
　次の試薬を用意した。全ての試薬は精製せず、市販の状態で使用した。
（1）ジエチル亜鉛（DEZ、≧52wt% Zn basis、アルドリッチ）、
（2）セレン粉（Se、100mesh、99.99%、trace metal basis、アルドリッチ）、
（3）テルル粉（Te、100mesh、99.99% trace metal basis、アルドリッチ）、
（4）トリ－n－オクチルホスフィン（TOP、≧96.0%、和光純薬）、
（5）オレイルアミン（OLA、＞98%、アルドリッチ）、
（6）オレイン酸（OA、99%、アルドリッチ）、
（7）１－オクタデセン（ODE、＞90%、東京化成）、
（8）１－ドデカンチオール（DDT、＞95%、東京化成）、
（9）ヘキサン（＞96%、和光純薬）、
（10）エタノール（96%、今津薬品工業）
（11）無水酢酸亜鉛（99.99%、アルドリッチ）
（12）酢酸インジウム（99.99%、アルドリッチ）
（13）パルミチン酸（95%、和光純薬）
（14）トリス（トリメチルシリル）ホスフィン（10wt%ヘキサン溶液、Stream Chemicals）
（15）イソプロパノール（＞99.7%、関東化学）
（16）トルエン（＞99.5%、関東化学）
（17）ジエチルジチオカルバミン酸亜鉛（＞94%、和光純薬）
（18）沃化銅（95%、和光純薬）
（19）沃化インジウム（99.998%、アルドリッチ）
（20）酢酸カドミウム二水和物（99.9%、和光純薬）
（21）オクチルアミン（98%、和光純薬）
（22）ブタノール（99%、和光純薬）
（23）メタノール（＞99.8%、関東化学）
（24）ステアリン酸亜鉛（10～11%（Zn）、和光純薬）
（25）硫黄粉末（99.98%、アルドリッチ） The raw materials used in the examples and comparative examples of the present invention are as follows.
〔raw materials〕
The following reagents were prepared. All reagents were not purified and were used commercially.
(1) Diethyl zinc (DEZ, ≧ 52wt% Zn basis, Aldrich),
(2) Selenium powder (Se, 100mesh, 99.99%, trace metal basis, Aldrich),
(3) Tellurium powder (Te, 100mesh, 99.99% trace metal basis, Aldrich),
(4) Tri-n-octylphosphine (TOP, ≧ 96.0%, Wako Pure Chemical Industries),
(5) oleylamine (OLA,> 98%, Aldrich),
(6) Oleic acid (OA, 99%, Aldrich),
(7) 1-octadecene (ODE,> 90%, Tokyo Kasei),
(8) 1-dodecanethiol (DDT,> 95%, Tokyo Kasei),
(9) Hexane (> 96%, Wako Pure Chemical)
(10) Ethanol (96%, Imazu Pharmaceutical)
(11) Anhydrous zinc acetate (99.99%, Aldrich)
(12) Indium acetate (99.99%, Aldrich)
(13) Palmitic acid (95%, Wako Pure Chemical Industries)
(14) Tris (trimethylsilyl) phosphine (10 wt% hexane solution, Stream Chemicals)
(15) Isopropanol (> 99.7%, Kanto Chemical)
(16) Toluene (> 99.5%, Kanto Chemical)
(17) Zinc diethyldithiocarbamate (> 94%, Wako Pure Chemical Industries)
(18) Copper iodide (95%, Wako Pure Chemical Industries)
(19) Indium iodide (99.998%, Aldrich)
(20) Cadmium acetate dihydrate (99.9%, Wako Pure Chemical Industries)
(21) Octylamine (98%, Wako Pure Chemical Industries)
(22) Butanol (99%, Wako Pure Chemical Industries)
(23) Methanol (> 99.8%, Kanto Chemical)
(24) Zinc stearate (10-11% (Zn), Wako Pure Chemical Industries)
(25) Sulfur powder (99.98%, Aldrich)
　以下、第１の実施形態に基づき、実施例１～１２及び比較例１～５を説明する。 Hereinafter, Examples 1 to 12 and Comparative Examples 1 to 5 will be described based on the first embodiment.
　＜実施例１＞
〔Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットの合成〕
　Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットを合成するために、上記試薬の秤量から合成終了までの一連の操作は、主に窒素ガスが充填されたグローブボックス中で行った。一部のグローブボックス外での操作に関しては、溶液が大気に触れないように、窒素ガスで充填した密閉容器中で行った。 <Example 1>
[Synthesis of Zn (Te 1-x , Se x ) colloidal quantum dots]
In order to synthesize Zn (Te 1-x , Se x ) colloidal quantum dots, a series of operations from the weighing of the reagent to the end of the synthesis were performed mainly in a glove box filled with nitrogen gas. Operation outside some glove boxes was performed in a sealed container filled with nitrogen gas so that the solution did not come into contact with the atmosphere.
〔原料溶液の調製〕
　Ｔｅ粉末：１．９１４２ｇ（１５ｍｍｏｌ）とＴＯＰ：５０ｍＬを三口フラスコ中に秤量し、アルゴンガスを通気しながら２５０℃に加熱し、Ｔｅ粉末が完全に溶解して黄透明色になるまで撹拌した。溶解後は室温まで放冷し、Ｔｅ原料液とした。また、Ｓｅ粉末：１．１８４５ｇ（１５ｍｍｏｌ）とＴＯＰ：５０ｍＬをバイアル中に秤量し、超音波洗浄機に投入して、Ｓｅ粉末を完全に溶解させ無色透明のＳｅ原料液とした。上述のＴｅ原料液、Ｓｅ原料液、ＴＯＰ、ＤＥＺをそれぞれ、コロイダル量子ドットのＳｅのモル組成比ｘSe＝０．４０になるように秤量し、１０ｍＬバイアル中で十分に混合して、原料溶液とした。なお、Ｚｎ原料液とＴｅ原料液とＳｅ原料液を個別に調製することもできるが、ＤＥＺは液状であるので、ここでは、Ｔｅ原料液とＳｅ原料液にＴＯＰとＤＥＺを混合・溶解し、第１混合液とした。 (Preparation of raw material solution)
Te powder: 1.9142 g (15 mmol) and TOP: 50 mL were weighed into a three-necked flask and heated to 250 ° C. while bubbling argon gas, and stirred until the Te powder was completely dissolved and became a yellow transparent color. After dissolution, the mixture was allowed to cool to room temperature to obtain a Te raw material liquid. Further, Se powder: 1.1845 g (15 mmol) and TOP: 50 mL were weighed in a vial and put into an ultrasonic cleaner to completely dissolve Se powder to obtain a colorless and transparent Se raw material liquid. The above Te raw material liquid, Se raw material liquid, TOP, DEZ are weighed so that the molar composition ratio Se of colloidal quantum dots x Se = 0.40 and mixed well in a 10 mL vial to obtain a raw material solution It was. In addition, although Zn raw material liquid, Te raw material liquid, and Se raw material liquid can also be prepared separately, DEZ is in a liquid state, and here, TOP and DEZ are mixed and dissolved in Te raw material liquid and Se raw material liquid, It was set as the 1st liquid mixture.
〔Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットの合成手順〕
　１００ｍＬの四つ口フラスコにキャッピング剤としてのＯＡ：６．４８ｍＬ（２０ｍｍｏｌ）と希釈剤としてのＯＤＥ：２０ｍＬをそれぞれ秤量して混合し、第２混合液を調製した。この第２混合液を撹拌しながら真空中で「１２０℃×３０分間」の脱気処理を行った。その後、この第２混合液をアルゴンガスにて大気圧に戻し、アルゴンガスを通気・撹拌しながら２９０℃まで昇温した。この第２混合液の温度が安定したことを確認した後、この第２混合液に上記第１混合液をシリンジを用いて素早く注入した。注入後の反応液を撹拌しながら、２７０℃の温度で１０分間保持してコロイダル量子ドットを成長させた後、室温まで放冷した。反応溶液は濁りがない透明な溶液であった。ここで、第２混合液の温度を２９０℃とすること、第１混合液を第２混合液に注入した後の成長温度を２７０℃とすること、その温度での成長時間を１０分間とすることは、すべて、平均粒径を４．０±０．１ｎｍに調整するための条件である。第２混合液の温度、第１混合液を第２混合液に注入した後の成長温度、その温度での成長時間、を調整することで、コロイダル量子ドットの粒径を調整することができる。以下の表２にこの条件を示す。 [Procedure for synthesizing Zn (Te 1-x , Se x ) colloidal quantum dots]
OA as a capping agent: 6.48 mL (20 mmol) and ODE as a diluent: 20 mL were weighed and mixed in a 100 mL four-necked flask to prepare a second mixed solution. The second mixture was stirred and degassed at 120 ° C. for 30 minutes. Then, this 2nd liquid mixture was returned to atmospheric pressure with argon gas, and it heated up to 290 degreeC, ventilating and stirring argon gas. After confirming that the temperature of this 2nd liquid mixture was stabilized, the said 1st liquid mixture was rapidly inject | poured into this 2nd liquid mixture using the syringe. While stirring the reaction liquid after the injection, the colloidal quantum dots were grown at a temperature of 270 ° C. for 10 minutes, and then allowed to cool to room temperature. The reaction solution was a clear solution without turbidity. Here, the temperature of the second liquid mixture is 290 ° C., the growth temperature after the first liquid mixture is injected into the second liquid mixture is 270 ° C., and the growth time at that temperature is 10 minutes. This is a condition for adjusting the average particle diameter to 4.0 ± 0.1 nm. By adjusting the temperature of the second mixed liquid, the growth temperature after the first mixed liquid is injected into the second mixed liquid, and the growth time at that temperature, the particle size of the colloidal quantum dots can be adjusted. Table 2 below shows this condition.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
〔Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットの抽出〕
　こうして得られた反応溶液：１２ｍＬにヘキサン：６ｍＬとエタノール：１８ｍＬを加えて凝集させた。遠心分離によって沈殿物としてコロイダル量子ドットを分離回収した。沈殿をヘキサン：６ｍＬに再分散させ、再度エタノール：１８ｍＬ加えて凝集させた。この操作を数回繰り返した後、室温で真空乾燥して残留するヘキサンとエタノールを除去した。これにより、コロイダル量子ドットを抽出した。 [Extraction of Zn (Te 1-x , Se x ) colloidal quantum dots]
To the reaction solution thus obtained: 12 mL, hexane: 6 mL and ethanol: 18 mL were added for aggregation. The colloidal quantum dots were separated and collected as a precipitate by centrifugation. The precipitate was redispersed in hexane: 6 mL, and ethanol: 18 mL was added again to cause aggregation. After repeating this operation several times, the remaining hexane and ethanol were removed by vacuum drying at room temperature. Thereby, colloidal quantum dots were extracted.
〔ＺｎＳシェルの成長〕
　こうして得られたＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットをＯＬＡ：１ｍＬ、ＴＯＰ：２ｍＬ、ＯＤＥ：１０ｍＬと混合し、撹拌しながら真空中で「１００℃×３０分間」の脱気処理を行った。その後、アルゴンガスにて大気圧に戻し、アルゴンガスを通気・撹拌しながら２４０℃まで昇温した。そこに、ＤＥＺ：０．０３４ｍＬ、ＤＤＴ：０．０７３ｍＬ、ＯＤＥ：６ｍＬを混合した溶液（約６ｍＬ）を３０分間かけて滴下した。このとき、溶液の温度を２４０℃に保持した。滴下終了後、２４０℃で１５分間保持し、室温まで放冷した。 [Growth of ZnS shell]
The Zn (Te 1-x , Se x ) colloidal quantum dots thus obtained were mixed with OLA: 1 mL, TOP: 2 mL, ODE: 10 mL, and degassed at “100 ° C. × 30 minutes” in vacuum with stirring. Went. Thereafter, the pressure was returned to atmospheric pressure with argon gas, and the temperature was raised to 240 ° C. while venting and stirring the argon gas. The solution (about 6 mL) which mixed DEZ: 0.034mL, DDT: 0.073mL, and ODE: 6mL was dripped there over 30 minutes. At this time, the temperature of the solution was kept at 240 ° C. After completion of dropping, the mixture was kept at 240 ° C. for 15 minutes and allowed to cool to room temperature.
〔Ｚｎ（Ｔｅ1-x，Ｓｅx）／ＺｎＳコアシェルコロイダル量子ドットの抽出〕
　こうして得られた反応溶液：２ｍＬにヘキサン：１ｍＬとエタノール：３ｍＬを加えて凝集させた。遠心分離によって沈殿物としてコロイダル量子ドットを分離回収した。沈殿をヘキサン：１ｍＬに再分散させ、再度エタノール：３ｍＬ加えて凝集させた。この操作を数回繰り返した後、室温で真空乾燥して残留するヘキサンとエタノールを除去した。これにより、コアシェルコロイダル量子ドットを抽出した。 [Extraction of Zn (Te 1-x , Se x ) / ZnS core-shell colloidal quantum dots]
To the reaction solution thus obtained: 2 mL, hexane: 1 mL and ethanol: 3 mL were added for aggregation. The colloidal quantum dots were separated and collected as a precipitate by centrifugation. The precipitate was redispersed in hexane: 1 mL, and agglomerated by adding 3 mL of ethanol again. After repeating this operation several times, the remaining hexane and ethanol were removed by vacuum drying at room temperature. Thereby, core-shell colloidal quantum dots were extracted.
　＜実施例２～５及び比較例１＞
　実施例２～５及び比較例１について、実施例１とそれぞれ同じＴｅ原料液、Ｓｅ原料液、ＴＯＰ、ＤＥＺ等を用いた。実施例２～５及び比較例１では、これらのＴｅ原料液、Ｓｅ原料液、ＴＯＰ、ＤＥＺ等を、上述した表２に示すように、コロイダル量子ドットのＳｅのモル組成比ｘSeとなるように、秤量するとともに、第２混合液の温度、第１混合液を第２混合液に注入した後の成長温度、その温度での成長時間を調整して、コロイダル量子ドットの粒径を調整した。それ以外は実施例１と同様にして、Ｚｎ（Ｔｅ1-x，Ｓｅx）／ＺｎＳコアシェルコロイダル量子ドットを合成した。 <Examples 2 to 5 and Comparative Example 1>
For Examples 2 to 5 and Comparative Example 1, the same Te raw material liquid, Se raw material liquid, TOP, DEZ and the like as in Example 1 were used. In Examples 2 to 5 and Comparative Example 1, these Te raw material liquid, Se raw material liquid, TOP, DEZ, and the like have a molar composition ratio x Se of colloidal quantum dots as shown in Table 2 above. And adjusting the particle size of the colloidal quantum dots by adjusting the temperature of the second mixed solution, the growth temperature after injecting the first mixed solution into the second mixed solution, and the growth time at that temperature. . Otherwise, in the same manner as in Example 1, Zn (Te 1-x , Se x ) / ZnS core-shell colloidal quantum dots were synthesized.
　＜比較例２＞
〔ＺｎＳｅコロイダル量子ドットの合成〕
〔原料溶液の調製〕
　無水酢酸亜鉛：１８．３ｍｇ（０．１ｍｍｏＬ）、ＯＤＥ：３．５ｍＬ（１０．９１ｍｍｏＬ）、ＯＬＡ：０．３３０ｍＬ（１．００ｍｍｏｌ）を１０ｍＬバイアル中に秤量し、６０℃に加温した振とう機で撹拌して、無水酢酸亜鉛を完全に溶解させ無色透明なＺｎ原料液を調製した。また、コロイダル量子ドットのＳｅのモル組成比ｘSe＝１．００になるように、Ｓｅ粉末：６３．２ｍｇ（０．８ｍｍｏｌ）、ＴＯＰ：２．０ｍＬ（４．４８ｍｍｏｌ）を別の１０ｍＬバイアル中に秤量し、超音波洗浄機中でＳｅ粉末を完全に溶解させて、無色透明のＳｅ原料液を調製した。 <Comparative example 2>
[Synthesis of ZnSe colloidal quantum dots]
(Preparation of raw material solution)
Anhydrous zinc acetate: 18.3 mg (0.1 mmol), ODE: 3.5 mL (10.91 mmol), OLA: 0.330 mL (1.00 mmol) were weighed into a 10 mL vial and shaken at 60 ° C. The mixture was stirred in a machine to completely dissolve anhydrous zinc acetate to prepare a colorless and transparent Zn raw material liquid. Further, Se powder: 63.2 mg (0.8 mmol), TOP: 2.0 mL (4.48 mmol) in another 10 mL vial so that the Se molar composition ratio x Se = 1.00 of the colloidal quantum dots. The Se powder was completely dissolved in an ultrasonic cleaner to prepare a colorless and transparent Se raw material liquid.
〔ＺｎＳｅコロイダル量子ドットの合成手順〕
　上記Ｚｎ原料液の入った１０ｍＬバイアルに上記Ｓｅ原料液：１．５ｍＬを加え、十分に撹拌した後、２８０℃に加温したオイルバスに浸漬し、アルゴンガスを通気しながら９分間保持した。その後、バイアルをオイルバスから取り出し、室温まで放冷した。反応溶液は淡い黄透明色であった。 [Procedure for synthesizing ZnSe colloidal quantum dots]
The Se raw material solution: 1.5 mL was added to a 10 mL vial containing the Zn raw material solution, and after sufficient stirring, the mixture was immersed in an oil bath heated to 280 ° C. and held for 9 minutes while venting argon gas. Thereafter, the vial was taken out from the oil bath and allowed to cool to room temperature. The reaction solution was light yellow and transparent.
〔反応溶液からのＺｎＳｅコロイダル量子ドットの抽出〕
　上記反応溶液からのＺｎＳｅコロイダル量子ドットの抽出はＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットと同様の手順で行った。 [Extraction of ZnSe colloidal quantum dots from reaction solution]
Extraction of ZnSe colloidal quantum dots from the reaction solution was performed in the same procedure as for Zn (Te 1-x , Se x ) colloidal quantum dots.
　比較例２について、上記以外は、実施例１と同様にして、ＺｎＳｅ／ＺｎＳコアシェルコロイダル量子ドットを合成した。上述した表２に比較例２のコロイダル量子ドットのＳｅのモル組成比ｘSe、第２混合液の温度、第１混合液を第２混合液に注入した後の成長温度、その温度での成長時間をそれぞれ示す。 About the comparative example 2, except having the above, it carried out similarly to Example 1, and synthesize | combined the ZnSe / ZnS core-shell colloidal quantum dot. Table 2 above shows the molar composition ratio x Se of the colloidal quantum dots of Comparative Example 2, the temperature of the second mixed liquid, the growth temperature after the first mixed liquid is injected into the second mixed liquid, and the growth at that temperature. Each time is shown.
　＜実施例６＞
　実施例１とそれぞれ同じＴｅ原料液、Ｓｅ原料液、ＴＯＰ、ＤＥＺをそれぞれ、コロイダル量子ドットのＳｅのモル組成比ｘSe＝０．３０になるように秤量し、１０ｍＬバイアル中で十分に混合して、第１混合液とした。一方、実施例１と同じＯＡとＯＤＥの混合溶液である第２混合液をアルゴンガス通気・撹拌しながら３１０℃まで昇温した。この第２混合液の温度が安定したことを確認した後、この第２混合液に上記第１混合液をシリンジを用いて素早く注入した。注入後の反応液は、撹拌しながら２９０℃の温度で１０分間保持してコロイダル量子ドットを成長させた後、室温まで放冷した。それ以外は実施例１と同様にして、Ｚｎ（Ｔｅ1-x，Ｓｅx）／ＺｎＳコアシェルコロイダル量子ドットを合成した。以下の表３にコロイダル量子ドットのＳｅのモル組成比ｘSe、第２混合液の温度、第１混合液を第２混合液に注入した後の成長温度、その温度での成長時間をそれぞれ示す。 <Example 6>
The same Te raw material liquid, Se raw material liquid, TOP and DEZ as in Example 1 were weighed so that the molar composition ratio of Se of colloidal quantum dots x Se = 0.30, and mixed well in a 10 mL vial. Thus, a first mixed solution was obtained. On the other hand, the second mixed liquid, which is the same mixed solution of OA and ODE as in Example 1, was heated to 310 ° C. while agitating and stirring argon gas. After confirming that the temperature of this 2nd liquid mixture was stabilized, the said 1st liquid mixture was rapidly inject | poured into this 2nd liquid mixture using the syringe. The reaction solution after the injection was stirred for 10 minutes at a temperature of 290 ° C. to grow colloidal quantum dots, and then allowed to cool to room temperature. Otherwise, in the same manner as in Example 1, Zn (Te 1-x , Se x ) / ZnS core-shell colloidal quantum dots were synthesized. Table 3 below shows the molar composition ratio x Se of the colloidal quantum dots, the temperature of the second liquid mixture, the growth temperature after the first liquid mixture is injected into the second liquid mixture, and the growth time at that temperature. .
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　＜実施例７～１２＞
　実施例７～１２について、実施例１とそれぞれ同じＴｅ原料液、Ｓｅ原料液、ＴＯＰ、ＤＥＺ等を用いた。実施例７～１２では、これらのＴｅ原料液、Ｓｅ原料液、ＴＯＰ、ＤＥＺ等を、上述した表３に示すように、コロイダル量子ドットのＳｅのモル組成比ｘＳｅとなるように、秤量するとともに、第２混合液の温度、第１混合液を第２混合液に注入した後の成長温度、その温度での成長時間を調整して、コロイダル量子ドットの粒径を調整した。それ以外は実施例６と同様にして、Ｚｎ（Ｔｅ1-x，Ｓｅx）／ＺｎＳコアシェルコロイダル量子ドットを合成した。 <Examples 7 to 12>
For Examples 7 to 12, the same Te raw material liquid, Se raw material liquid, TOP, DEZ and the like as in Example 1 were used. In Examples 7 to 12, these Te raw material liquid, Se raw material liquid, TOP, DEZ, and the like were weighed so that the molar composition ratio of Se of colloidal quantum dots xSe as shown in Table 3 above. The particle size of the colloidal quantum dots was adjusted by adjusting the temperature of the second liquid mixture, the growth temperature after injecting the first liquid mixture into the second liquid mixture, and the growth time at that temperature. Otherwise, in the same manner as in Example 6, Zn (Te 1-x , Se x ) / ZnS core-shell colloidal quantum dots were synthesized.
　＜比較例３＞
〔ＩｎＰ／ＺｎＳコロイダル量子ドットの合成〕
〔ＩｎＰコアコロイダル量子ドットの合成〕
　酢酸インジウム（Ｉｎ(Ｃ2Ｈ3Ｏ2)3）：０．０４ｍｍｏｌをパルミチン酸（Ｃ16Ｈ32Ｏ2）：０．１２ｍｍｏｌとＯＤＥ（Ｃ18Ｈ36）：２ｍＬに加え、撹拌しながら１１０℃に昇温し、真空処理を１．５時間実施し、Ｉｎ原料液を調製した。一方、トリス（トリメチルシリル）ホスフィン（Ｐ(ＳｉＣ3Ｈ9)  3）：０．０２ｍｍｏｌをＯＤＥ（Ｃ18Ｈ36）：３ｍＬに溶解し、Ｐ原料液を調製した。上記Ｉｎ原料液を、アルゴンガスにて大気圧に戻し、アルゴンガス通気・撹拌しながら３００℃に昇温した。この昇温したＩｎ原料液にシリンジにて所定量秤量された上記Ｐ原料液を素早く注入した後、直ちに室温まで急冷し、ＩｎＰコアコロイダル量子ドット反応液を調製した。 <Comparative Example 3>
[Synthesis of InP / ZnS colloidal quantum dots]
[Synthesis of InP core colloidal quantum dots]
Indium acetate (In (C 2 H 3 O 2 ) 3 ): 0.04 mmol was added to palmitic acid (C 16 H 32 O 2 ): 0.12 mmol and ODE (C 18 H 36 ): 2 mL, and the mixture was stirred with 110 The temperature was raised to 0 ° C. and vacuum treatment was carried out for 1.5 hours to prepare an In raw material liquid. On the other hand, tris (trimethylsilyl) phosphine (P (SiC 3 H 9 )   3 ): 0.02 mmol was dissolved in ODE (C 18 H 36 ): 3 mL to prepare a P raw material solution. The In raw material liquid was returned to atmospheric pressure with argon gas, and the temperature was raised to 300 ° C. while aerated and stirred with argon gas. The P raw material solution weighed in a predetermined amount with a syringe was quickly injected into the heated In raw material solution, and then immediately cooled to room temperature to prepare an InP core colloidal quantum dot reaction solution.
〔ＺｎＳシェル成長〕
　上記ＩｎＰコアコロイダル量子ドット反応液に酢酸亜鉛（Ｚｎ(Ｃ2Ｈ3Ｏ2)3）：０．１ｍｍｏｌを投入し、撹拌しながら２３０℃まで昇温し、数時間保持した。その後、この昇温保持した液に１－ドデカンチオール（Ｃ12Ｈ26Ｓ）：０．０４ｍｍｏｌを素早く注入し、１時間保持して、ＩｎＰ／ＺｎＳコアシェルコロイダル量子ドット反応液を調製した。 [ZnS shell growth]
Zinc acetate (Zn (C 2 H 3 O 2 ) 3 ): 0.1 mmol was added to the above InP core colloidal quantum dot reaction solution, heated to 230 ° C. with stirring, and maintained for several hours. Thereafter, 1-dodecanethiol (C 12 H 26 S): 0.04 mmol was quickly injected into this liquid held at elevated temperature and held for 1 hour to prepare an InP / ZnS core-shell colloidal quantum dot reaction liquid.
〔洗浄・回収〕
　上記ＩｎＰ／ＺｎＳコアシェルコロイダル量子ドット反応液を室温まで冷却し、この冷却した液にイソプロパノール（Ｃ3Ｈ8Ｏ）：４０ｍＬを加え、ＩｎＰ／ＺｎＳコアシェルコロイダル量子ドットを凝集させた。遠心分離にて回収された沈殿物をトルエン（Ｃ7Ｈ8）適当量で再分散させ、イソプロパノールによる凝集と遠心分離による回収とトルエンによる再分散の一連の工程を数回繰り返した。最終的に得られた遠心分離による沈殿物を室温で真空乾燥し、残留している有機溶媒を除去して、ＩｎＰ／ＺｎＳコアシェルコロイダル量子ドットを得た。 [Washing / collecting]
The InP / ZnS core-shell colloidal quantum dot reaction liquid was cooled to room temperature, and isopropanol (C 3 H 8 O): 40 mL was added to the cooled liquid to aggregate the InP / ZnS core-shell colloidal quantum dots. The precipitate recovered by centrifugation was redispersed with an appropriate amount of toluene (C 7 H 8 ), and a series of steps of aggregation with isopropanol, recovery by centrifugation, and redispersion with toluene were repeated several times. The finally obtained precipitate by centrifugation was vacuum-dried at room temperature, and the remaining organic solvent was removed to obtain InP / ZnS core-shell colloidal quantum dots.
　＜比較例４＞
〔ＣｕＩｎＳ2－ＺｎＳ合金／ＺｎＳコロイダル量子ドットの合成〕
〔ＣｕＩｎＳ2－ＺｎＳ合金コアコロイダル量子ドットの合成〕
　 ジエチルジチオカルバミン酸亜鉛（Ｃ10Ｈ20Ｎ2Ｓ4Ｚｎ）：０．２５ｍｍｏｌをＴＯＰ（Ｐ(Ｃ8Ｈ17)3）：３．０ｍＬに室温にて溶解し、そこから１．０ｍＬを採取し、ＯＤＥ（Ｃ18Ｈ36）：４．０ｍＬと混合した。これを亜鉛－硫黄溶液とした。沃化銅（ＣｕＩ）：０．１ｍｍｏｌを６０℃にてＯＬＡ（Ｃ18Ｈ37Ｎ）：３．０ｍＬに溶解した。これをＣｕ液とした。沃化インジウム（ＩｎＩ3）：０．１ｍｍｏｌを室温にてＯＬＡ：３．０ｍｌに溶解した。これをＩｎ溶液とした。亜鉛－硫黄溶液：２．５ｍＬと銅溶液：１．２５ｍＬとＩｎ溶液：１．２５ｍＬを秤量し、これらを混合した後、アルゴンガスをバブリングしながら２００℃まで昇温し、そのまま６０秒間維持し、ＣｕＩｎＳ2－ＺｎＳ合金コアコロイダル量子ドット反応液を調製した。 <Comparative example 4>
[Synthesis of CuInS 2 -ZnS alloy / ZnS colloidal quantum dots]
[Synthesis of CuInS 2 -ZnS alloy core colloidal quantum dots]
Zinc diethyldithiocarbamate (C 10 H 20 N 2 S 4 Zn): 0.25 mmol was dissolved in TOP (P (C 8 H 17 ) 3 ): 3.0 mL at room temperature, and 1.0 mL was collected therefrom. , ODE (C 18 H 36 ): mixed with 4.0 mL. This was used as a zinc-sulfur solution. Copper iodide (CuI): 0.1 mmol was dissolved in OLA (C 18 H 37 N): 3.0 mL at 60 ° C. This was made into Cu liquid. Indium iodide (InI 3 ): 0.1 mmol was dissolved in OLA: 3.0 ml at room temperature. This was designated as an In solution. Zinc-sulfur solution: 2.5 mL, copper solution: 1.25 mL, and In solution: 1.25 mL were weighed and mixed, then heated to 200 ° C. while bubbling argon gas and maintained for 60 seconds. A CuInS 2 —ZnS alloy core colloidal quantum dot reaction solution was prepared.
〔ＺｎＳシェル成長〕
　上記ＣｕＩｎＳ2－ＺｎＳ合金コアコロイダル量子ドット反応液：１．０ｍＬからＣｕＩｎＳ2－ＺｎＳ合金コアコロイダル量子ドット：２．２６ｍｇを取り出した。非常に薄い硫化亜鉛シェルを成長させる場合には、これを、キャッピング剤としてＯＡ（Ｃ18Ｈ34Ｏ2）：３２μＬを含んだジエチルジチオカルバミン酸亜鉛濃度：５．５ｍＭのＴＯＰとＯＤＥの混合溶液：１．５ｍＬに再分散させた。比較的薄い硫化亜鉛シェルを成長させる場合には、キャッピング剤としてオレイン酸（Ｃ18Ｈ34Ｏ2）：２１０μＬを含んだジエチルジチオカルバミン酸亜鉛濃度：３５．３ｍＭのＴＯＰとＯＤＥの混合溶液：２．０ｍＬに再分散させた。これらを１４０℃にて５時間反応させ、ＣｕＩｎＳ2－ＺｎＳ合金／ＺｎＳコアシェルコロイダル量子ドット反応液を調製した。 [ZnS shell growth]
CuInS 2 —ZnS alloy core colloidal quantum dot: 2.26 mg was taken out from 1.0 mL of the above CuInS 2 —ZnS alloy core colloidal quantum dot reaction solution. When growing a very thin zinc sulfide shell, this is used as a capping agent OA (C 18 H 34 O 2 ): 32 μL of zinc diethyldithiocarbamate concentration: 5.5 mM TOP and ODE mixed solution: Redispersed to 1.5 mL. When growing a relatively thin zinc sulfide shell, zinc diethyldithiocarbamate containing 210 μL of oleic acid (C 18 H 34 O 2 ) as a capping agent: 35.3 mM of a mixed solution of TOP and ODE: 2. Redispersed in 0 mL. These were reacted at 140 ° C. for 5 hours to prepare a CuInS 2 —ZnS alloy / ZnS core-shell colloidal quantum dot reaction solution.
〔洗浄・回収〕
　上記ＣｕＩｎＳ2－ＺｎＳ合金／ＺｎＳコアシェルコロイダル量子ドット反応液を室温まで冷却し、イソプロパノール（Ｃ3Ｈ8Ｏ）：４０ｍＬを加え、ＣｕＩｎＳ2－ＺｎＳ合金／ＺｎＳコアシェルコロイダル量子ドットを凝集させた。遠心分離にて回収された沈殿物をトルエン（Ｃ7Ｈ8）適当量で再分散させ、イソプロパノールによる凝集と遠心分離による回収とトルエンによる再分散の一連の工程を数回繰り返した。最終的に得られた遠心分離による沈殿物を室温で真空乾燥し、残留している有機溶媒を除去して、ＣｕＩｎＳ2－ＺｎＳ合金／ＺｎＳコアシェルコロイダル量子ドットを得た。 [Washing / collecting]
The CuInS 2 —ZnS alloy / ZnS core / shell colloidal quantum dot reaction liquid was cooled to room temperature, isopropanol (C 3 H 8 O): 40 mL was added, and the CuInS 2 —ZnS alloy / ZnS core / shell colloidal quantum dots were aggregated. The precipitate recovered by centrifugation was redispersed with an appropriate amount of toluene (C 7 H 8 ), and a series of steps of aggregation with isopropanol, recovery by centrifugation, and redispersion with toluene were repeated several times. The finally obtained precipitate by centrifugation was vacuum-dried at room temperature, and the remaining organic solvent was removed to obtain a CuInS 2 —ZnS alloy / ZnS core-shell colloidal quantum dot.
　＜比較例５＞
〔ＣｄＳｅ／ＺｎＳコロイダル量子ドットの合成〕
〔コアとして用いるＣｄＳｅコロイダル量子ドットの合成〕
（Ｃｄ原料液の調製）
　酢酸カドミウム二水和物粉末：４２．６ｍｇ（０．１６ｍｍｏｌ）を１２ｍＬねじ口瓶に秤量し、ＯＡ：２６４μＬ及びＯＤＥ：８．０ｍＬを加えた。１８０℃のオイルバスを用いて６０分間加熱し、粉末を溶解してＣｄ原料液を調製した。このＣｄ原料液は無色透明であった。
（Ｓｅ原料液の調製）
　Ｓｅ粉末：９４．８ｍｇ（１．２ｍｍｏｌ）を１２ｍＬねじ口瓶に秤量し、ＴＯＰ：５．０ｍＬを加え、チューブミキサーと超音波での撹拌を行うことで、粉末は簡単に溶解してＳｅ原料液を調製した。このＳｅ原料液は無色透明であった。
（Ｃｄ原料液とＳｅ原料液の混合・反応）
　上記Ｃｄ原料液：２．０ｍＬと上記Ｓｅ原料液：１．０ｍＬをそれぞれ採取し、１２ｍＬねじ口瓶中で混合した。キャッピング剤としてオクチルアミン：１５０μＬを加えた。チューブミキサーでよく撹拌した後、２８０℃のオイルバスに浸漬し、緑色光を発光する粒径に成長するまで、所定時間加熱反応を行った。 <Comparative Example 5>
[Synthesis of CdSe / ZnS colloidal quantum dots]
[Synthesis of CdSe colloidal quantum dots used as cores]
(Preparation of Cd raw material liquid)
Cadmium acetate dihydrate powder: 42.6 mg (0.16 mmol) was weighed into a 12 mL screw cap bottle, and OA: 264 μL and ODE: 8.0 mL were added. It heated for 60 minutes using the oil bath of 180 degreeC, the powder was melt | dissolved, and Cd raw material liquid was prepared. This Cd raw material liquid was colorless and transparent.
(Preparation of Se raw material liquid)
Se powder: 94.8 mg (1.2 mmol) is weighed into a 12 mL screw cap bottle, TOP: 5.0 mL is added, and the powder is easily dissolved by stirring with a tube mixer and ultrasonic waves. A liquid was prepared. This Se raw material liquid was colorless and transparent.
(Mixing and reaction of Cd raw material liquid and Se raw material liquid)
The Cd raw material solution: 2.0 mL and the Se raw material solution: 1.0 mL were collected and mixed in a 12 mL screw mouth bottle. As a capping agent, 150 μL of octylamine was added. After stirring well with a tube mixer, it was immersed in an oil bath at 280 ° C. and subjected to a heating reaction for a predetermined time until it grew to a particle size emitting green light.
〔合成後のコロイド溶液からのＣｄＳｅコアコロイダル量子ドットの回収〕
　反応溶液：約３．０ｍＬを試験管に分け、ブタノールを４倍量（１２．０ｍＬ）加え希釈した。次に、この希釈液にメタノールを２倍量（６．０ｍＬ）加え、量子ドットを凝集させた。遠心分離を１５分間行い、無色透明の上澄み溶液と真っ赤な沈殿に分離し、上澄み溶液を除去した。 [Recovery of CdSe core colloidal quantum dots from colloidal solution after synthesis]
Reaction solution: About 3.0 mL was divided into test tubes, and 4-fold amount (12.0 mL) of butanol was added for dilution. Next, 2 times the amount of methanol (6.0 mL) was added to the diluted solution to aggregate the quantum dots. Centrifugation was carried out for 15 minutes to separate a colorless and transparent supernatant solution and a bright red precipitate, and the supernatant solution was removed.
〔被覆用ＺｎＳ原料液の調製〕
（Ｚｎ（ｓｔ）2をＺｎ源にドデカンチオールをＳ源に用いた被覆）
　Ｚｎ（ｓｔ）2：３１．６ｍｇ（０．０５ｍｍｏｌ）を１２ｍＬねじ口瓶に秤量し、ＯＤＥ：２．０ｍＬを加えた。この液を１４０℃のオイルバスで１０分間程度加熱し、粉末を融解した。ねじ口瓶を引上げて室温まで冷却すると、粉末は再析出したが、このまま用いた。Ｓはドデカンチオールを溶媒兼Ｓ原料として用いた。 [Preparation of ZnS raw material solution for coating]
(Coating using Zn (st) 2 as Zn source and dodecanethiol as S source)
Zn (st) 2 : 31.6 mg (0.05 mmol) was weighed into a 12 mL screw mouth bottle, and ODE: 2.0 mL was added. This solution was heated in an oil bath at 140 ° C. for about 10 minutes to melt the powder. When the screw cap bottle was pulled up and cooled to room temperature, the powder re-deposited but was used as it was. S used dodecanethiol as a solvent and S raw material.
〔ＺｎＳ原料液への再分散と混合・被覆処理〕
（再分散と混合）
　ＣｄＳｅコアコロイダル量子ドットの沈殿が入った試験管にＳ原料液：２．０ｍＬを加え、再分散させた。それを準備しておいたＺｎ原料液の入ったバイアルに移した。ドデカンチオールがキャッピング剤として働くことを期待して、キャッピング剤は添加しなかった。
（加熱・被覆処理）
　出発溶液を２１０℃のオイルバスで１２０分間加熱した。 [Re-dispersion in ZnS raw material and mixing / coating]
(Redispersion and mixing)
S raw material liquid: 2.0 mL was added to a test tube containing a precipitate of CdSe core colloidal quantum dots and redispersed. It was transferred to a vial containing the prepared Zn raw material solution. In the hope that dodecanethiol would act as a capping agent, no capping agent was added.
(Heating and coating treatment)
The starting solution was heated in a 210 ° C. oil bath for 120 minutes.
〔洗浄・回収〕
　ＣｄＳｅ／ＺｎＳコアシェルコロイダル量子ドット反応液を室温まで冷却し、イソプロパノール（Ｃ3Ｈ8Ｏ）：４０ｍＬを加え、ＣｄＳｅ／ＺｎＳコアシェルコロイダル量子ドットを凝集させた。遠心分離にて回収された沈殿物をトルエン（Ｃ7Ｈ8）適当量で再分散させ、イソプロパノールによる凝集と遠心分離による回収とトルエンによる再分散の一連の工程を数回繰り返した。最終的に得られた遠心分離による沈殿物を室温で真空乾燥し、残留している有機溶媒を除去して、ＣｄＳｅ／ＺｎＳコアシェルコロイダル量子ドットを合成した。 [Washing / collecting]
CdSe / ZnS core-shell colloidal quantum dot reaction liquid was cooled to room temperature, isopropanol (C 3 H 8 O): 40 mL was added, and CdSe / ZnS core-shell colloidal quantum dots were aggregated. The precipitate recovered by centrifugation was redispersed with an appropriate amount of toluene (C 7 H 8 ), and a series of steps of aggregation with isopropanol, recovery by centrifugation, and redispersion with toluene were repeated several times. The finally obtained precipitate obtained by centrifugation was vacuum-dried at room temperature to remove the remaining organic solvent, and CdSe / ZnS core-shell colloidal quantum dots were synthesized.
　以下、第２の実施形態に基づき、実施例１３～２４及び比較例６～９を説明する。 Hereinafter, Examples 13 to 24 and Comparative Examples 6 to 9 will be described based on the second embodiment.
　＜実施例１３＞
〔Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットの合成〕
　Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットを合成するために、試薬の秤量から合成終了までの一連の操作は、実施例１と同様に、主に窒素ガスが充填されたグローブボックス中で行った。一部のグローブボックス外での操作に関しては、実施例１と同様に、溶液が大気に触れないように、窒素ガスで充填した密閉容器中で行った。 <Example 13>
[Synthesis of Zn (Te 1-x , S x ) colloidal quantum dots]
In order to synthesize Zn (Te 1-x , S x ) colloidal quantum dots, a series of operations from the weighing of reagents to the end of synthesis were carried out in a glove box mainly filled with nitrogen gas, as in Example 1. I went there. The operation outside some glove boxes was performed in a sealed container filled with nitrogen gas in the same manner as in Example 1 so that the solution did not come into contact with the atmosphere.
〔Ｔｅ原料液の調製〕
　Ｔｅ粉末：１１４．８ｍｇ（０．９０ｍｍｏｌ）とＴＯＰ：３．００ｍＬ（６．７２ｍｍｏｌ）を１０ｍＬセプタムバイアル中に秤量し、アルゴンガスを通気しながら２００℃に加熱し、Ｔｅ粉末が完全に溶解して黄透明色になるまで撹拌した。溶解後は室温まで放冷し、Ｔｅ原料液（０．３Ｍ）とした。
〔ＺｎＴｅ原料液の調製〕
上記Ｔｅ原料液（０．３Ｍ）をコロイダル量子ドットのＳのモル組成比ｘS＝０．４５（Ｔｅのモル組成比１－ｘS＝０．５５）になるように秤量し、そこにＺｎ原料液としてのジエチル亜鉛（ＤＥＺ）：２５μＬ（０．２５ｍｍｏｌ）を添加し、ＴＯＰにて全容量が２ｍＬとなるように調整した。チューブミキサーにて十分に混合すると、溶液の色は黄透明色から無色透明に変化した。このＺｎ原料液とＴｅ原料液とを混合した混合溶液を第３混合液とした。
〔Ｓ原料液の調製〕
Ｓ原料液としての１－ドデカンチオールをコロイダル量子ドットのＳのモル組成比ｘS＝０．４５になるように秤量し、そこにキャッピング剤としてのＯＬＡ：９．４ｍＬ（２０ｍｍｏｌ）を添加し、希釈剤としてのＯＤＥにて全容量が２０ｍＬとなるように調整した。チューブミキサーにて十分に混合し、このＳ原料液とキャッピング剤と希釈剤を混合して第４混合液を調製した。 [Preparation of Te raw material liquid]
Te powder: 114.8 mg (0.90 mmol) and TOP: 3.00 mL (6.72 mmol) were weighed into a 10 mL septum vial and heated to 200 ° C. while bubbling argon gas, and the Te powder was completely dissolved. The mixture was stirred until it became a yellow transparent color. After dissolution, the mixture was allowed to cool to room temperature to obtain a Te raw material liquid (0.3M).
[Preparation of ZnTe raw material solution]
The Te raw material liquid (0.3 M) was weighed so that the molar composition ratio x S of colloidal quantum dots x s = 0.45 (the molar composition ratio of Te 1-x s = 0.55). Diethyl zinc (DEZ) as a raw material liquid: 25 μL (0.25 mmol) was added, and the total volume was adjusted to 2 mL with TOP. When mixed well with a tube mixer, the color of the solution changed from yellow transparent to colorless and transparent. A mixed solution obtained by mixing the Zn raw material liquid and the Te raw material liquid was used as a third mixed liquid.
[Preparation of S raw material solution]
1-dodecanethiol as the S raw material liquid was weighed so that the molar composition ratio x S of colloidal quantum dots x S = 0.45, and OLA as a capping agent: 9.4 mL (20 mmol) was added thereto, The total volume was adjusted to 20 mL with ODE as a diluent. This was mixed sufficiently with a tube mixer, and this S raw material liquid, capping agent and diluent were mixed to prepare a fourth mixed liquid.
〔Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットの合成手順〕
　上記第４混合液を撹拌しながら真空中で「１２０℃×３０分間」の脱気処理を行った。その後、アルゴンガスにて大気圧に戻し、アルゴンガスを通気・撹拌しながら３００℃まで昇温した。この第４混合液の温度が安定したことを確認した後、この第４混合液に上記第３混合液をシリンジを用いて素早く注入した。注入後の反応液を撹拌しながら、２９０℃の温度で１５分間保持してコロイダル量子ドットを成長させた後、室温まで放冷した。反応溶液は濁りがない透明な溶液であった。ここで、第４混合液の温度を３００℃にすること、第３混合液を第４混合液に注入した後の成長温度を２９０℃にすること、その温度での成長時間を１５分間とすることは、すべて、平均粒径を６．０±０．１ｎｍに調整するための条件である。第４混合液の温度、第３混合液を第４混合液に注入した後の成長温度、その温度での成長時間、を調整することで、コロイダル量子ドットの粒径を調整することができる。以下の表４にこの条件を示す。 [Procedure for synthesizing Zn (Te 1-x , S x ) colloidal quantum dots]
The degassing process of “120 ° C. × 30 minutes” was performed in vacuum while stirring the fourth mixed solution. Thereafter, the pressure was returned to atmospheric pressure with argon gas, and the temperature was raised to 300 ° C. while the argon gas was aerated and stirred. After confirming that the temperature of this 4th liquid mixture was stabilized, the said 3rd liquid mixture was rapidly inject | poured into this 4th liquid mixture using the syringe. While stirring the reaction liquid after the injection, the colloidal quantum dots were grown at a temperature of 290 ° C. for 15 minutes, and then allowed to cool to room temperature. The reaction solution was a clear solution without turbidity. Here, the temperature of the fourth mixed solution is set to 300 ° C., the growth temperature after the third mixed solution is injected into the fourth mixed solution is set to 290 ° C., and the growth time at that temperature is set to 15 minutes. This is a condition for adjusting the average particle diameter to 6.0 ± 0.1 nm. By adjusting the temperature of the fourth mixed liquid, the growth temperature after the third mixed liquid is injected into the fourth mixed liquid, and the growth time at that temperature, the particle size of the colloidal quantum dots can be adjusted. Table 4 below shows this condition.
Figure JPOXMLDOC01-appb-T000009
Figure JPOXMLDOC01-appb-T000009
　実施例１３で得られたＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットの抽出、こうして得られたＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットをコアとするＺｎＳシェルの成長、こうして得られたＺｎ（Ｔｅ1-x，Ｓx）／ＺｎＳコアシェルコロイダル量子ドットの抽出については、それぞれ実施例１と同様に行った。 Extraction of Zn (Te 1-x , S x ) colloidal quantum dots obtained in Example 13, growth of ZnS shell with Zn (Te 1-x , S x ) colloidal quantum dots thus obtained as a core, thus Extraction of the obtained Zn (Te 1-x , S x ) / ZnS core-shell colloidal quantum dots was performed in the same manner as in Example 1.
　＜実施例１４～１７及び比較例６＞
　実施例１４～１７及び比較例６について、実施例１３とそれぞれ同じＴｅ原料液、Ｓ原料液、ＴＯＰ、ＤＥＺ等を用いた。実施例１４～１７及び比較例６では、これらのＴｅ原料液、Ｓ原料液、ＴＯＰ、ＤＥＺ等を、上述した表４に示すように、コロイダル量子ドットのＳのモル組成比ｘSとなるように、秤量するとともに、第４混合液の温度、第３混合液を第４混合液に注入した後の成長温度、その温度での成長時間を調整して、コロイダル量子ドットの粒径を６．０±０．１ｎｍに調整した。それ以外は実施例１３と同様にして、Ｚｎ（Ｔｅ1-x，Ｓx）／ＺｎＳコアシェルコロイダル量子ドットを合成した。 <Examples 14 to 17 and Comparative Example 6>
For Examples 14 to 17 and Comparative Example 6, the same Te raw material liquid, S raw material liquid, TOP, DEZ and the like as in Example 13 were used. In Examples 14 to 17 and Comparative Example 6, these Te raw material liquid, S raw material liquid, TOP, DEZ, and the like have a molar composition ratio x S of S of colloidal quantum dots as shown in Table 4 above. And adjusting the temperature of the fourth mixed solution, the growth temperature after injecting the third mixed solution into the fourth mixed solution, and the growth time at that temperature to adjust the particle size of the colloidal quantum dots to 6. Adjusted to 0 ± 0.1 nm. Otherwise, in the same manner as in Example 13, a Zn (Te 1-x , S x ) / ZnS core-shell colloidal quantum dot was synthesized.
　＜比較例７＞
〔ＺｎＳコロイダル量子ドットの合成〕
［原料溶液の調製］
　無水酢酸亜鉛：１８．３ｍｇ（０．１ｍｍｏＬ）、ＯＤＥ：３．５ｍＬ（１０．９１ｍｍｏＬ）、ＯＬＡ：０．３３０ｍＬ（１．００ｍｍｏｌ）を１０ｍＬバイアル中に秤量し、６０℃に加温した振とう機で撹拌して、無水酢酸亜鉛を完全に溶解させ無色透明なＺｎ原料液を調製した。また、コロイダル量子ドットのＳのモル組成比ｘS＝１．００になるように、Ｓ粉末：２５．７ｍｇ（０．８ｍｍｏｌ）、ＴＯＰ：２．０ｍＬ（４．４８ｍｍｏｌ）を別の１０ｍＬバイアル中に秤量し、超音波洗浄機中でＳ粉末を完全に溶解させて、無色透明のＳ原料液を調製した。 <Comparative Example 7>
[Synthesis of ZnS colloidal quantum dots]
[Preparation of raw material solution]
Anhydrous zinc acetate: 18.3 mg (0.1 mmol), ODE: 3.5 mL (10.91 mmol), OLA: 0.330 mL (1.00 mmol) were weighed into a 10 mL vial and shaken at 60 ° C. The mixture was stirred in a machine to completely dissolve anhydrous zinc acetate to prepare a colorless and transparent Zn raw material liquid. Further, S powder: 25.7 mg (0.8 mmol) and TOP: 2.0 mL (4.48 mmol) were added to another 10 mL vial so that the molar composition ratio of S of the colloidal quantum dot x S = 1.00. The S powder was completely dissolved in an ultrasonic cleaner to prepare a colorless and transparent S raw material solution.
〔ＺｎＳコロイダル量子ドットの合成手順〕
　上記Ｚｎ原料液の入った１０ｍＬバイアルに上記Ｓ原料液：１．５ｍＬを加え、十分に撹拌した後、２８０℃に加温したオイルバスに浸漬し、アルゴンガスを通気しながら９分間保持した。その後、バイアルをオイルバスから取り出し、室温まで放冷した。反応溶液は淡い黄透明色であった。 [Procedure for synthesizing ZnS colloidal quantum dots]
The S raw material solution: 1.5 mL was added to a 10 mL vial containing the Zn raw material solution, and after sufficient stirring, immersed in an oil bath heated to 280 ° C. and held for 9 minutes while venting argon gas. Thereafter, the vial was taken out from the oil bath and allowed to cool to room temperature. The reaction solution was light yellow and transparent.
〔反応溶液からのＺｎＳコロイダル量子ドットの抽出〕
　上記反応溶液からのＺｎＳコロイダル量子ドットの抽出はＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットと同様の手順で行った。 [Extraction of ZnS colloidal quantum dots from reaction solution]
Extraction of ZnS colloidal quantum dots from the reaction solution was performed in the same procedure as for Zn (Te 1-x , S x ) colloidal quantum dots.
　上述した表４に比較例７のコロイダル量子ドットのＳのモル組成比ｘS、第４混合液の温度、第３混合液を第４混合液に注入した後の成長温度、その温度での成長時間をそれぞれ示す。 In Table 4 above, the molar composition ratio x S of the colloidal quantum dots of Comparative Example 7, the temperature of the fourth mixed solution, the growth temperature after injecting the third mixed solution into the fourth mixed solution, and the growth at that temperature Each time is shown.
　＜実施例１８＞
　実施例１３とそれぞれ同じＴｅ原料液、ＴＯＰ、ＤＥＺをそれぞれ、コロイダル量子ドットのＳのモル組成比ｘS＝０．３５になるように秤量し、１０ｍＬバイアル中で十分に混合して、第３混合液とした。一方、Ｓ原料をＳのモル組成比ｘS＝０．３５になるように秤量し、そこにＯＡとＯＤＥを添加して作製した第４混合液をアルゴンガス通気・撹拌しながら３１０℃まで昇温した。この第４混合液の温度が安定したことを確認した後、この第４混合液に上記第３混合液をシリンジを用いて素早く注入した。注入後の反応液は、撹拌しながら２９０℃の温度で１０分間保持してコロイダル量子ドットを成長させた後、室温まで放冷した。それ以外は実施例１３と同様にＺｎ（Ｔｅ1-x，Ｓx）／ＺｎＳコアシェルコロイダル量子ドットを合成した。以下の表５にコロイダル量子ドットのＳのモル組成比ｘS、第４混合液の温度、第３混合液を第４混合液に注入した後の成長温度、その温度での成長時間をそれぞれ示す。 <Example 18>
The same Te raw material solution, TOP, DEZ as in Example 13 were weighed so that the molar composition ratio S of colloidal quantum dots x s = 0.35, and mixed well in a 10 mL vial. A mixed solution was obtained. On the other hand, the S raw material was weighed so that the molar composition ratio x S of S was 0.35, and OA and ODE were added thereto, and the fourth mixed liquid was raised to 310 ° C. while aerated and stirred with argon gas. Warm up. After confirming that the temperature of this 4th liquid mixture was stabilized, the said 3rd liquid mixture was rapidly inject | poured into this 4th liquid mixture using the syringe. The reaction solution after the injection was stirred for 10 minutes at a temperature of 290 ° C. to grow colloidal quantum dots, and then allowed to cool to room temperature. Otherwise, Zn (Te 1-x , S x ) / ZnS core-shell colloidal quantum dots were synthesized in the same manner as in Example 13. Table 5 below shows the molar composition ratio x S of colloidal quantum dots S , the temperature of the fourth liquid mixture, the growth temperature after injecting the third liquid mixture into the fourth liquid mixture, and the growth time at that temperature. .
Figure JPOXMLDOC01-appb-T000010
Figure JPOXMLDOC01-appb-T000010
　＜実施例１９～２４＞
　実施例１９～２４では、これらのＴｅ原料液、ＴＯＰ、ＤＥＺ等を、上述した表５に示すように、コロイダル量子ドットのＳのモル組成比ｘSとなるように、秤量するとともに、Ｓ原料をＳのモル組成比ｘSになるように秤量し、そこにＯＡとＯＤＥを添加して作製した第４混合液の温度、第３混合液を第４混合液に注入した後の成長温度、その温度での成長時間を調整して、コロイダル量子ドットの粒径を調整した。それ以外は実施例１８と同様にして、Ｚｎ（Ｔｅ1-x，Ｓx）／ＺｎＳコアシェルコロイダル量子ドットを合成した。 <Examples 19 to 24>
In Examples 19 to 24, these Te raw material liquids, TOP, DEZ, and the like are weighed so that the molar composition ratio x S of S of colloidal quantum dots is as shown in Table 5 above, and the S raw material Is measured so as to have a molar composition ratio x S of S , and the temperature of the fourth mixed solution prepared by adding OA and ODE thereto, the growth temperature after injecting the third mixed solution into the fourth mixed solution, The particle size of the colloidal quantum dots was adjusted by adjusting the growth time at that temperature. Other than that was carried out similarly to Example 18, and the Zn (Te1 -x , Sx ) / ZnS core-shell colloidal quantum dot was synthesize | combined.
　＜比較例８＞
〔ＩｎＰ／ＺｎＳコロイダル量子ドットの合成〕
　比較例８のＩｎＰコアコロイダル量子ドットの合成では、昇温したＩｎ原料液にシリンジにて所定量秤量されたＰ原料液を素早く注入した後、比較例３では直ちに室温まで急冷していたのに対して、比較例８では３０分間維持し、ＩｎＰコアコロイダル量子ドット反応液を調製した。この３０分維持する以外は、比較例３と同様にしてＩｎＰコアコロイダル量子ドット反応液を調製し、更に続いてＩｎＰ／ＺｎＳコアシェルコロイダル量子ドットを得た。 <Comparative Example 8>
[Synthesis of InP / ZnS colloidal quantum dots]
In the synthesis of the InP core colloidal quantum dot of Comparative Example 8, the P raw material liquid weighed in a predetermined amount with a syringe was quickly injected into the heated In raw material liquid, and then immediately cooled to room temperature in Comparative Example 3. In contrast, Comparative Example 8 was maintained for 30 minutes to prepare an InP core colloidal quantum dot reaction solution. An InP core colloidal quantum dot reaction solution was prepared in the same manner as in Comparative Example 3 except that this was maintained for 30 minutes, and then an InP / ZnS core-shell colloidal quantum dot was obtained.
　＜比較例９＞
〔ＣｕＩｎＳ2－ＺｎＳ合金／ＺｎＳコロイダル量子ドットの合成〕
　比較例９のＣｕＩｎＳ2－ＺｎＳ合金コアコロイダル量子ドットの合成では、アルゴンガスをバブリングしながら２００℃まで昇温し、比較例４ではそのまま６０秒間維持していたのに対して、比較例９ではそのまま３分間維持して、ＣｕＩｎＳ2－ＺｎＳ合金コアコロイダル量子ドット反応液を調製した。この３分間維持する以外は、比較例４と同様にしてＣｕＩｎＳ2－ＺｎＳ合金コアコロイダル量子ドット反応液を調製し、更に続いてＣｕＩｎＳ2－ＺｎＳ合金／ＺｎＳコアシェルコロイダル量子ドットを得た。 <Comparative Example 9>
[Synthesis of CuInS 2 -ZnS alloy / ZnS colloidal quantum dots]
In the synthesis of the CuInS 2 —ZnS alloy core colloidal quantum dot of Comparative Example 9, the temperature was raised to 200 ° C. while bubbling argon gas, and in Comparative Example 4, the temperature was maintained as it was for 60 seconds, whereas in Comparative Example 9, The reaction mixture was maintained for 3 minutes to prepare a CuInS 2 —ZnS alloy core colloidal quantum dot reaction solution. A CuInS 2 —ZnS alloy core colloidal quantum dot reaction liquid was prepared in the same manner as in Comparative Example 4 except that this was maintained for 3 minutes, and then a CuInS 2 —ZnS alloy / ZnS core shell colloidal quantum dot was obtained.
　＜比較例１０＞
〔ＣｄＳｅ／ＺｎＳコロイダル量子ドットの合成〕
  比較例１０のＣｄＳｅ／ＺｎＳコロイダル量子ドットの合成では、Ｃｄ原料液とＳｅ原料液の混合液にキャッピング剤を加えて撹拌混合した後、２８０℃のオイルバスに浸漬し、比較例５では緑色光を発光する粒径に成長するまで、所定時間加熱反応を行ったのに対して、比較例１０では赤色光を発光する粒径まで成長するまで、所定時間の加熱反応を行った。これ以外は、比較例５と同様にしてＣｄＳｅ／ＺｎＳコアシェルコロイダル量子ドットを得た。 <Comparative Example 10>
[Synthesis of CdSe / ZnS colloidal quantum dots]
In the synthesis of the CdSe / ZnS colloidal quantum dots of Comparative Example 10, a capping agent was added to the liquid mixture of the Cd raw material liquid and the Se raw material liquid, and the mixture was stirred and mixed, and then immersed in an oil bath at 280 ° C. In contrast, in Comparative Example 10, the heating reaction was performed for a predetermined time until it grew to a particle size emitting red light. Other than this, CdSe / ZnS core-shell colloidal quantum dots were obtained in the same manner as in Comparative Example 5.
　＜Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットの比較評価＞
　実施例１～１２及び比較例１～５で得られたＺｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットについて、平均粒径を４．０±０．１ｎｍの一定にして、上述したＳｅのモル仕込比（ｘSe）を０．００から１．００に変量したときの（1）吸光・発光特性、及び（2）コロイダル量子ドットの平均粒径を下記に示す方法で調べた。これらの結果を上述した表２、表３及び以下の表６に示す。 <Comparative evaluation of Zn (Te 1-x , Se x ) colloidal quantum dots>
With respect to the Zn (Te 1-x , Se x ) colloidal quantum dots obtained in Examples 1 to 12 and Comparative Examples 1 to 5, the average particle diameter was kept constant at 4.0 ± 0.1 nm, and the above-mentioned Se When the molar charge ratio (x Se ) was varied from 0.00 to 1.00, (1) absorption / luminescence characteristics and (2) average particle diameter of colloidal quantum dots were examined by the following methods. These results are shown in Tables 2 and 3 and Table 6 below.
Figure JPOXMLDOC01-appb-T000011
Figure JPOXMLDOC01-appb-T000011
　（1）吸光・発光特性
　吸光・発光特性はそれぞれ日立製の分光測定装置（U4100）と日本分光製の蛍光分光測定装置（FP6500）にて測定した。吸光・発光ピークのエネルギー［ｅＶ］は、ピーク波長λ[ｎｍ]より、次の式（７）を用いて求めた。ここで、プランク定数は６．６２６０７×１０-34［Ｊｓｅｃ］、ｃは真空中の光速：２．９９７９２×１０8［ｍ／ｓｅｃ］である。
　　　　　Ｅ＝プランク定数×ｃ／λ　（７）
ここで、吸光ピークのエネルギー値を光学ギャップとした。発光ピークの波長を発光波長とした。吸光・発光ピークの各エネルギー値の差をストークスシフトとした。発光ピークの半分の高さにおける発光プロファイルの幅を半値全幅とした。 (1) Absorption / Emission Characteristics Absorption / emission characteristics were measured with a Hitachi spectrophotometer (U4100) and a JASCO spectrofluorometer (FP6500), respectively. The energy [eV] of the light absorption / emission peak was determined from the peak wavelength λ [nm] using the following formula (7). Here, the Planck's constant is 6.62607 × 10 −34 [Jsec], and c is the speed of light in a vacuum: 2.99792 × 10 8 [m / sec].
E = Planck constant × c / λ (7)
Here, the energy value of the absorption peak was defined as the optical gap. The wavelength of the emission peak was defined as the emission wavelength. The difference between the energy values of the absorption and emission peaks was defined as Stokes shift. The width of the light emission profile at half the height of the light emission peak was defined as the full width at half maximum.
　（2）コロイダル量子ドットの平均粒径
　コロイダル量子ドットの平均粒径の算出には粉末Ｘ線回折測定法（XRD：X－ray diffraction）を用いた。回転型陰極Ｘ線発生源と湾曲モノクロメータを備えたＸ線回折装置（RINT2500、リガク）を使って、Ｘ線加速電圧：４０ｋＶ、電流：３７５ｍＡ（１５ｋＷ）で発生したＣｕ－Ｋα線を、無反射石英板上のコロイダル量子ドットに照射して測定した。平均粒子径ｄXRDはＸＲＤにより得られた回折パターンの半値幅（FWHM：Full Width at Half Maximum）から次の式（８）に示すシェラーの式を用いて算出した。ここで、Ｂは回折パターンの半値幅［ｒａｄ］、θは回折角［ｒａｄ］とする。シェラー定数には０．９を用いた。（１１１）面、（２２０）面、（３１１）面の各回折面における回折パターンのｃｏｓθと０．９λ／Ｂのプロットの最小二乗法による線形近似から平均粒子径ｄXRDを求めた。
　　　　　ｄXRD＝０．９λ／Ｂｃｏｓθ　（８） (2) Average particle diameter of colloidal quantum dots The average particle diameter of colloidal quantum dots was calculated by using a powder X-ray diffraction measurement method (XRD: X-ray diffraction). Using an X-ray diffractometer (RINT2500, Rigaku) equipped with a rotating cathode X-ray generation source and a curved monochromator, Cu-Kα rays generated at an X-ray acceleration voltage of 40 kV and current of 375 mA (15 kW) It was measured by irradiating colloidal quantum dots on a reflective quartz plate. The average particle diameter d XRD was calculated from the full width at half maximum (FWHM) of the diffraction pattern obtained by XRD using the Scherrer equation shown in the following equation (8). Here, B is the half width [rad] of the diffraction pattern, and θ is the diffraction angle [rad]. 0.9 was used for the Scherrer constant. The average particle diameter d XRD was obtained from the linear approximation by the least square method of the cos θ and 0.9λ / B plots of the diffraction patterns on the diffraction planes of the (111) plane, the (220) plane, and the (311) plane.
d XRD = 0.9λ / Bcos θ (8)
　上述した表２から明らかなように、平均粒径を４．０±０．１ｎｍに調整したとき、Ｓｅのモル仕込比（ｘSe）を０＜ｘSe＜１の範囲にて調整すると、Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットの発光エネルギーを、緑色領域：２．１５～２．４５ｅＶの範囲内で所望の値に制御することができた。特に、Ｓｅのモル仕込比（ｘSe）が０．２５～０．４０の範囲にて、Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットは発光エネルギーの最小値：約２．３ｅＶを示していた。 As apparent from Table 2 above, when the average particle size was adjusted to 4.0 ± 0.1 nm, the molar feed ratio (x Se ) of Se was adjusted within the range of 0 <x Se <1, Zn The emission energy of the (Te 1-x , Se x ) colloidal quantum dots could be controlled to a desired value in the green region: 2.15 to 2.45 eV. In particular, when the Se molar charge ratio (x Se ) is in the range of 0.25 to 0.40, the Zn (Te 1-x , Se x ) colloidal quantum dot exhibits a minimum emission energy of about 2.3 eV. It was.
　Ｚｎ（Ｔｅ1-x，Ｓｅx）のＳｅのモル仕込比（ｘSe）を０．３０の一定にして、平均粒径を調整したときのコロイダル量子ドットの合成条件を上述した表３に示す。 Table 3 above shows the synthesis conditions of colloidal quantum dots when the average particle size is adjusted by setting the Se molar charge ratio (x Se ) of Zn (Te 1-x , Se x ) to be constant at 0.30. .
　上述した表３から明らかなように、Ｓｅのモル仕込比（ｘSe）を０．３０に調整したとき、ＯＡとＯＤＥの混合溶液である第２混合液の温度、原料溶液である第１混合液をこの第２混合液に注入した後の成長温度、その温度での成長時間を調整して、平均粒径を３．５～６．３ｎｍに調整することで、量子サイズ効果により、Ｚｎ（Ｔｅ1-x，Ｓｅx）コロイダル量子ドットの発光エネルギーを緑色領域：２．１５～２．４５ｅＶに調整することができた。特に、色域拡大に求められている緑色波長は５３０ｎｍ程度（２．３３～２．３４ｅＶ）であって、これを実現している実施例１１に対して、表３の「緑色領域拡大への適合」の項目において、適合する場合を「有り」、適合しない場合を「無し」とした。 As is apparent from Table 3 above, when the Se feed ratio (x Se ) is adjusted to 0.30, the temperature of the second mixed solution, which is a mixed solution of OA and ODE, and the first mixing, which is a raw material solution By adjusting the growth temperature after injecting the liquid into the second mixed liquid and the growth time at that temperature, the average particle size is adjusted to 3.5 to 6.3 nm. The emission energy of the Te 1-x , Se x ) colloidal quantum dots could be adjusted to the green region: 2.15 to 2.45 eV. In particular, the green wavelength required for the color gamut expansion is about 530 nm (2.33 to 2.34 eV). In the “Compliance” item, “Yes” is indicated when conforming, and “None” when not conforming.
　表６から明らかなように、実施例７のコロイダル量子ドットを、可視蛍光が緑色光のＣｄを含まないコロイダル量子ドットの代表例であるＩｎＰ／ＺｎＳ（比較例３）や三元系化合物半導体（比較例４）と比較したときに、第一に、平均粒径を大きくすることができるので、発光波長制御性が大きく向上しており、第二に、発光スペクトルの半値全幅（ＦＷＨＭ）のシャープさが大きく向上していることから、Ｃｄを含まない既存のコロイダル量子ドットより良好な色度を実現でき、色域拡大が期待される。また、第三に、ストークスシフトが大きく低減し、エネルギーロスが大きく低減している。色域拡大に関して、ＣｄＳｅ／ＺｎＳ（比較例５）と同等の特性を示しており、Ｃｄ代替の動きが加速している中、ＣｄＳｅ／ＺｎＳを代替するコロイダル量子ドットの有力候補だと考えることができることが判明した。 As is clear from Table 6, the colloidal quantum dots of Example 7 were made of InP / ZnS (Comparative Example 3), which is a representative example of colloidal quantum dots that do not contain Cd whose visible fluorescence is green, and ternary compound semiconductors ( When compared with Comparative Example 4), first, the average particle size can be increased, so the emission wavelength controllability is greatly improved, and second, the full width at half maximum (FWHM) of the emission spectrum is sharp. Therefore, the chromaticity better than that of the existing colloidal quantum dots not containing Cd can be realized, and the gamut expansion is expected. Third, the Stokes shift is greatly reduced, and the energy loss is greatly reduced. Regarding color gamut expansion, it shows the same characteristics as CdSe / ZnS (Comparative Example 5), and while the movement of Cd substitution is accelerating, it can be considered as a promising candidate for colloidal quantum dots that substitute CdSe / ZnS. It turns out that you can.
　＜Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットの比較評価＞
  実施例１３～２４及び比較例６～７で得られたＺｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットについて、平均粒径を６．０±０．１ｎｍの一定にして、上述したＳのモル仕込比（ｘS）を０．００から１．００に変量したときの（1）吸光・発光特性、及び（2）コロイダル量子ドットの平均粒径を上述した方法で調べた。これらの結果を上述した表４、表５に示す。 <Comparison evaluation of Zn (Te1 -x , Sx ) colloidal quantum dots>
For the Zn (Te 1-x , S x ) colloidal quantum dots obtained in Examples 13 to 24 and Comparative Examples 6 to 7, the average particle diameter was kept constant at 6.0 ± 0.1 nm, and the above S When the molar charge ratio (x S ) was varied from 0.00 to 1.00, (1) absorption / luminescence characteristics, and (2) the average particle size of colloidal quantum dots were examined by the method described above. These results are shown in Tables 4 and 5 described above.
Figure JPOXMLDOC01-appb-T000012
Figure JPOXMLDOC01-appb-T000012
　表４から明らかなように、平均粒径を６．０±０．１ｎｍに調整したとき、Ｓのモル仕込比（ｘS）を０＜ｘS＜１の範囲にて調整すると、Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットの発光エネルギーを、赤色領域：１．８０～２．１０ｅＶの範囲内で所望の値に制御することができた。特に、Ｓのモル仕込比（ｘS）が０．３０～０．３５の範囲にて、Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットは発光エネルギーの最小値：１．９６ｅＶを示していた。 As is apparent from Table 4, when the average particle size is adjusted to 6.0 ± 0.1 nm, the molar charge ratio (x S ) of S is adjusted in the range of 0 <x S <1, Zn (Te The emission energy of the 1-x , S x ) colloidal quantum dots could be controlled to a desired value within the red region: 1.80 to 2.10 eV. In particular, when the molar charge ratio (x S ) of S is in the range of 0.30 to 0.35, the Zn (Te 1-x , S x ) colloidal quantum dot exhibits a minimum emission energy of 1.96 eV. It was.
　Ｚｎ（Ｔｅ1-x，Ｓx）のＳのモル仕込比（ｘS）を０．３５の一定にして、平均粒径を調整したときのコロイダル量子ドットの合成条件を上述した表５に示す。 Table 5 shows the synthesis conditions for colloidal quantum dots when the average particle size is adjusted with the S molar charge ratio (x S ) of Zn (Te 1-x , S x ) kept constant at 0.35. .
　表５から明らかなように、Ｓのモル仕込比（ｘS）を０．３５に調整したとき、ＯＡとＯＤＥの混合溶液である第４混合液の温度、原料溶液である第３混合液をこの第４混合液に注入した後の成長温度、その温度での成長時間を調整して、平均粒径を５．５～８．３ｎｍに調整することで、量子サイズ効果により、Ｚｎ（Ｔｅ1-x，Ｓx）コロイダル量子ドットの発光エネルギーを赤色領域：１．８０～２．１０ｅＶに調整することができた。特に、色域拡大に求められている赤色波長は６３０ｎｍ程度（１．９６～１．９７ｅＶ）であって、これを実現している実施例１９に対して、表５の「赤色領域拡大への適合」の項目において、適合する場合を「有り」、適合しない場合を「無し」とした。 As is apparent from Table 5, when the molar charge ratio of S (x S ) was adjusted to 0.35, the temperature of the fourth mixed solution, which is a mixed solution of OA and ODE, and the third mixed solution, which is a raw material solution, By adjusting the growth temperature after the injection into the fourth mixed solution and the growth time at that temperature, and adjusting the average particle size to 5.5 to 8.3 nm, Zn (Te 1 The emission energy of the -x , S x ) colloidal quantum dots could be adjusted to the red region: 1.80 to 2.10 eV. In particular, the red wavelength required for the color gamut expansion is about 630 nm (1.96 to 1.97 eV). In the “Compliance” item, “Yes” is indicated when conforming, and “None” when not conforming.
　表７から明らかなように、可視蛍光が赤色光のＣｄを含まないコロイダル量子ドットの代表例であるＩｎＰ／ＺｎＳ（比較例８）や三元系化合物半導体（比較例９）と比較したときに、第一に、平均粒径を大きくすることができるので、発光波長制御性が大きく向上しており、第二に、発光スペクトルの半値全幅（ＦＷＨＭ）のシャープさが大きく向上していることから、Ｃｄを含まない既存のコロイダル量子ドットより良好な色度を実現でき、色域拡大が期待される。また、第三に、ストークスシフトが大きく低減し、エネルギーロスが大きく低減している。色域拡大に関して、ＣｄＳｅ／ＺｎＳ（比較例１０）と同等の特性を示しており、Ｃｄ代替の動きが加速している中、ＣｄＳｅ／ＺｎＳを代替するコロイダル量子ドットの有力候補だと考えることができることが判明した。 As is apparent from Table 7, when visible fluorescence is compared with InP / ZnS (Comparative Example 8) and ternary compound semiconductors (Comparative Example 9), which are representative examples of colloidal quantum dots that do not contain Cd of red light. First, since the average particle size can be increased, the emission wavelength controllability is greatly improved, and, second, the sharpness of the full width at half maximum (FWHM) of the emission spectrum is greatly improved. , Chromaticity better than that of existing colloidal quantum dots not containing Cd can be realized, and a color gamut expansion is expected. Third, the Stokes shift is greatly reduced, and the energy loss is greatly reduced. It shows the same characteristics as CdSe / ZnS (Comparative Example 10) in terms of color gamut expansion. While the movement of Cd substitution is accelerating, it can be considered as a promising candidate for colloidal quantum dots that replace CdSe / ZnS. It turns out that you can.
　本発明の可視蛍光を発するコロイダル量子ドットは、ディスプレイ、照明、医療用画像、バイオセンサー、ＬＥＤ、レーザーの分野で利用することができる。 The colloidal quantum dots emitting visible fluorescence of the present invention can be used in the fields of displays, illumination, medical images, biosensors, LEDs, and lasers.

Claims (5)

  1. 　化合物半導体からなるシェルで被覆され、前記シェルのコアをなすコア粒子であって、近紫外領域又は青色領域の波長を有する励起光を照射したときに可視蛍光を発するＣｄを含まないコロイダル量子ドットであって、
    　化学式Ａ（Ｂ１1-x，Ｂ２x）（ただし、０＜ｘ＜１）で表され、ＡサイトにII族元素としてのＺｎを、Ｂ１サイトにVI族元素としてのＴｅを、Ｂ２サイトにVI族元素としてのＳｅ又はＳをそれぞれ有し、
      平均粒径が１ｎｍ以上１０ｎｍ以下であることを特徴とする可視蛍光を発するＣｄを含まないコロイダル量子ドット。     A colloidal quantum dot that is coated with a shell made of a compound semiconductor and forms the core of the shell, and does not contain Cd that emits visible fluorescence when irradiated with excitation light having a wavelength in the near ultraviolet region or blue region. There,
    Chemical formula A (B1 1-x , B2 x ) (where 0 <x <1), Zn as a Group II element at the A site, Te as a Group VI element at the B1 site, and VI at the B2 site Each having Se or S as a group element;
    A colloidal quantum dot that does not contain Cd and emits visible fluorescence, wherein the average particle diameter is 1 nm or more and 10 nm or less.
  2. 　前記Ｂ２サイトがＳｅであって、可視蛍光が緑色光である請求項１記載のＣｄを含まないコロイダル量子ドット。 The colloidal quantum dot containing no Cd according to claim 1, wherein the B2 site is Se and the visible fluorescence is green light.
  3. 　前記Ｂ２サイトがＳであって、可視蛍光が赤色光である請求項１記載のＣｄを含まないコロイダル量子ドット。 The colloidal quantum dot containing no Cd according to claim 1, wherein the B2 site is S and the visible fluorescence is red light.
  4. 　Ｚｎ原料液とＴｅ原料液とＳｅ原料液とを混合して調製された第１混合液又はキャッピング剤と希釈剤とを混合して調製された第２混合液のいずれか一方の液を２００℃～３５０℃の温度に加熱し、前記加熱した一方の液に前記いずれか他方の液を非酸化性雰囲気下で所定量注入し、前記一方の液に前記他方の液を注入した液を２００℃～３５０℃の温度に調整し、１分～５時間保持することにより、可視蛍光が緑色光であるＣｄを含まないコロイダル量子ドットを製造する方法。 One of the first mixed liquid prepared by mixing the Zn raw material liquid, the Te raw material liquid, and the Se raw material liquid or the second mixed liquid prepared by mixing the capping agent and the diluent is 200 ° C. Heated to a temperature of ˜350 ° C., a predetermined amount of the other liquid was injected into the heated one liquid in a non-oxidizing atmosphere, and a liquid obtained by injecting the other liquid into the one liquid was 200 ° C. A method for producing a colloidal quantum dot containing no Cd whose visible fluorescence is green light by adjusting the temperature to ˜350 ° C. and holding it for 1 minute to 5 hours.
  5. 　Ｚｎ原料液とＴｅ原料液とを混合して調製された第３混合液又はＳ原料液とキャッピング剤と希釈剤とを混合して調製された第４混合液のいずれか一方の液を２００℃～３５０℃の温度に加熱し、前記加熱した一方の液に前記いずれか他方の液を非酸化性雰囲気下で所定量注入し、前記一方の液に前記他方の液を注入した液を２００℃～３５０℃の温度に調整し、１分～５時間保持することにより、可視蛍光が赤色光であるＣｄを含まないコロイダル量子ドットを製造する方法。 One of the third mixed liquid prepared by mixing the Zn raw material liquid and the Te raw material liquid or the fourth mixed liquid prepared by mixing the S raw material liquid, the capping agent, and the diluent is 200 ° C. Heated to a temperature of ˜350 ° C., a predetermined amount of the other liquid was injected into the heated one liquid in a non-oxidizing atmosphere, and a liquid obtained by injecting the other liquid into the one liquid was 200 ° C. A method for producing a colloidal quantum dot containing no Cd whose visible fluorescence is red light by adjusting the temperature to ˜350 ° C. and holding it for 1 minute to 5 hours.
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