KR20140074128A

KR20140074128A - Quantum dot of agins_2 core doped group 10 metal- znse shell, composition of the same and preparing method of the same

Info

Publication number: KR20140074128A
Application number: KR1020120142354A
Authority: KR
Inventors: 이인호; 송지영; 구자정
Original assignee: 도레이케미칼 주식회사
Priority date: 2012-12-07
Filing date: 2012-12-07
Publication date: 2014-06-17

Abstract

The present invention relates to a quantum dot of a group 10 metal-doped AgInS_2-ZnSe shell composite structure, a composition of the same, and a method for manufacturing the same and, more specifically, to a quantum dot of a composite structure forming a core having a group 10 element doped on a AgInS_2 quantum dot and a shell of ZnSe at the outer surface of the core, a composition which is suitable to be used for manufacturing the same, and a method for effectively and economically manufacturing the same.

Description

[0001] The present invention relates to an AgInS2 core-ZnSe shell composite quantum dot doped with a Group 10 metal, a composition thereof, and a method for manufacturing the same.

The present invention relates to quantum dots of a novel core-shell composite structure having a broad wavelength absorption band without using cadmium (Cd).

Quantum dots (QDs) are semiconducting nano-sized particles with a three-dimensionally limited size and exhibit excellent optical and electrical properties that are not possessed by semiconducting materials in a bulk state. For example, quantum dots may be made of the same material, but the color of light emitted may vary depending on the size of the particles. Due to such characteristics, quantum dots are attracting attention as next generation high brightness light emitting diodes (LEDs), bio sensors, lasers, and solar cell nano materials.

Currently, the production method that is commonly used to form quantum dots is nonhydrolytic synthesis. According to this method, a nucleus is formed (nuclalization) by using a pyrolysis reaction by rapid injection of a metalorganic compound at room temperature as a precursor or precursor into a high-temperature solvent, and then the nucleus is grown by applying a temperature, . The quantum dots mainly synthesized by this method contain cadmium (Cd) such as cadmium selenium (CdSe) or cadmium tellurium (CdTe). However, considering the current trend of pursuing the green industry due to heightened awareness of environmental problems, it is necessary to minimize the use of cadmium (Cd) which is one of the typical environmental pollutants polluting water quality and soil.

Therefore, it is considered to manufacture quantum dots as a semiconductor material not containing cadmium as an alternative for replacing existing CdSe quantum dots or CdTe quantum dots. Indium sulfide (InS ₂ ) quantum dots are one of them. Particularly, since indium sulfide (InS ₂ ) has a bulk band gap of 2.1 eV and InS ₂ quantum dot can emit light in a visible light region, it can be used for manufacturing a high-luminance light emitting diode device. However, since Group 13 and Group 16 are generally difficult to synthesize, it is not only difficult to mass-produce indium sulfide quantum dots, but also has a disadvantage in that the particle size uniformity is secured and the quantum yield (QY) is poorer than that of conventional CdSe.

Therefore, the demand for the development of new quantum dots without using cadmium is increasing.

The present inventors have found that when metal is used together with a metal in the production of a quantum dot, it plays a role of surfactant and also solves the surface defects of the quantum dot, thereby preventing electrons from being easily recombined and reducing the luminous efficiency It is also known that coating the core with a shell of a group 12 group-16 compound having a band gap larger than that of the core can solve the problem of maintaining the emission stability or controlling the size of the quantum dot to some extent Thereby completing the present invention.

Accordingly, the present inventors intend to provide a quantum dot of a new core-shell composite structure capable of solving the problem of environmental pollution while improving the problem of existing quantum dots and having a wide range of wavelength absorption bands without using cadmium.

According to an aspect of the present invention, there is provided a quantum dot having a composite structure in which a ZnSe shell is formed on an AgInS ₂ core doped with a Group 10 element, A core comprising a structure nanocluster and at least one doping material selected from the group consisting of nickel (Ni), palladium (Pd), and platinum (Pt); And a shell containing zinc selenide (ZnSe).

In one preferred embodiment of the present invention, the doping material may include at least one selected from the group consisting of nickel (Ni), palladium (Pd), and platinum (Pt).

In one preferred embodiment of the present invention, the three-dimensional structure nanoclusters may have an average particle diameter of 2 to 8 nm, and the core may have an average particle diameter of 2.1 to 9 nm.

In another preferred embodiment of the present invention, the shell further includes zinc sulfide (ZnS), and a ZnSe shell layer may be formed on the outer side of the core and a ZnS shell layer may be formed on the outer side of the ZnSe shell layer.

In another preferred embodiment of the present invention, the average thickness of the shell is 0.2 to 5 nm, and the average thickness ratio of the ZnSe shell layer and the ZnS shell layer is 1: 1 to 3.

Further, as a preferred embodiment of the present invention, the quantum dots of the composite structure of the present invention are blue-shifted to absorb wavelength band light in the visible light region, that is, light in the wavelength band of 440 to 680 nm, blue color) of 460 to 500 nm, a green color of 500 to 530 nm, a yellow color of 530 to 560 nm, an orange color of 560 to 600 nm, and a red color of 600 to 680 nm .

Another aspect of the present invention relates to a quantum dot composition of the above composite structure, which is a binary structure nanocluster precursor containing a silver precursor, an indium precursor, a capping agent, a surfactant and an organic solvent; A sulfur (S) precursor; A doping material precursor containing an organic solvent and at least one doping material selected from nickel (Ni), palladium (Pd), and platinum (Pt); And a ZnSe precursor.

In one preferred embodiment of the present invention, the quantum dot composition of the composite structure may further include a ZnS precursor; the ZnS precursor is a Zn precursor containing zinc and a C12 to C20 carboxylic acid; And an S precursor for a shell containing sulfur and a trialkylphosphine represented by the following general formula (3).

(3)

In Formula 3, R ¹ to R ^{3 are} independent, and R ¹ to R ³ Each is a C5 to C12 linear or branched alkyl group.

In another preferred embodiment of the present invention, the silver precursor may include at least one selected from the group consisting of silver nitrate, silver stearate and silver acetate.

In one preferred embodiment of the present invention, the indium precursor is selected from the group consisting of indium hydroxide, indium nitrate hydrate, indium acetate hydrate, indium acetylacetonate, Indium acetate, and indium acetate.

As a preferred embodiment of the present invention, the capping agent may be a compound represented by the following general formula (1).

[Chemical Formula 1]

In Formula 1, R ¹ and R ² are independent and each of R ¹ and R ² is a C 5 to C 20 alkyl group.

In another preferred embodiment of the present invention, the surfactant may include C10-C16 alkyl thiol.

In another preferred embodiment of the present invention, the sulfur precursor is sulfur; And a primary amine represented by the following formula (2).

(2)

In Formula 2, R ¹ and R ² are independent and each of R ¹ and R ² is a C 5 to C 20 alkyl group.

In another preferred embodiment of the present invention, the organic solvent of the precursor of the binary structure nanocluster precursor and the organic solvent of the precursor of the doping material are independent, and each of these organic solvents is composed of C12 to C20 alkenes and C8 to C20 And a carboxylic acid.

In another preferred embodiment of the present invention, the binary structure nanocluster precursor may include a silver (Ag) precursor and the indium (In) precursor in a molar ratio of 1: 3 to 10.

In another preferred embodiment of the present invention, the AgInS ₂ quantum dot composition of the present invention may be characterized by containing silver precursor, indium precursor and sulfur precursor in a molar ratio of 1: 3 to 8: 5-12.

In another preferred embodiment of the present invention, the silver precursor and the doping material precursor are contained in a molar ratio of 1: 0.008 to 0.1.

In another preferred embodiment of the present invention, the ZnSe precursor is a Zn precursor containing zinc and a C12 to C20 carboxylic acid; And a Se precursor containing sulfur and a trialkylphosphine represented by the following general formula (3).

(3)

As another preferred embodiment of the present invention, the ZnSe precursor may include zinc (Zn) and selenium (Se) in a molar ratio of 1: 0.9 to 1.1.

Another aspect of the present invention relates to a method for producing quantum dots of the core-shell composite structure, comprising the steps of: preparing a solution containing a binary structure nanoparticle of indium (In) and silver (Ag); Adding a sulfur (S) precursor to the solution to prepare a solution containing a ternary structure nanocluster; Preparing a solution containing a core for doping reaction and nanoparticle growth at 110 DEG C to 180 DEG C after a doping material precursor is added to a solution containing a ternary structure nanocluster; Introducing and reacting a Zn precursor into a solution containing the core; And a Se precursor solution for a shell, and then reacting to form and grow a ZnSe shell.

In another preferred embodiment of the present invention, the quantum dots of the core-shell composite structure are prepared by preparing a solution including a binary structure nanoparticle of indium (In) and silver (Ag); Adding a sulfur (S) precursor to the solution to prepare a solution containing a ternary structure nanocluster; Introducing a doping material precursor into a solution containing a ternary structure nano cluster, growing a doping reaction and nanoparticles at 110 to 180 ° C to prepare a solution containing the core; And introducing and reacting a ZnSe precursor into a solution containing the core to form and grow a ZnSe shell.

In another preferred embodiment of the present invention, a method of fabricating a quantum dot of a core-shell composite structure of the present invention comprises: forming and growing a ZnSe shell after forming and growing a ZnSe shell; To form a ZnS shell layer outside the ZnSe shell layer.

According to a preferred embodiment of the present invention, the step of preparing a solution containing the binary structure nanoclusters may include a step of mixing an indium precursor, a silver precursor, a capping agent represented by the following Chemical Formula 2 and an organic solvent Removing excess moisture and oxygen; And a step of adding a surfactant to the mixed solution from which water and oxygen have been removed and reacting at 110 to 180 ° C and a nitrogen atmosphere to prepare a solution containing a binary structure nanocluster.

In another preferred embodiment of the present invention, the step of preparing the solution including the three-dimensional structure nanoclusters may be performed at 110 to 180 ° C under a nitrogen atmosphere.

In another preferred embodiment of the present invention, the step of forming and growing the ZnSe shell may be performed at 110 to 180 ° C for 1 to 3 hours.

The quantum dot of the core-shell composite structure of the present invention not only uses cadmium but also can absorb a wide range of wavelengths and can be controlled in a specific wavelength range by controlling quantum dot size, composition ratio thereof, So that the manufacturing process is simple, and the economical efficiency is excellent.

1 is a schematic view of a quantum dot of a core-shell composite structure of the present invention in which a ZnSe shell is formed.
2 is a schematic view of a quantum dot of a core-shell composite structure of the present invention in which a ZnSe shell layer and a ZnS shell layer are formed.
3 is a photograph showing the luminescence states of the quantum dots prepared in Examples 1-1 to 1-7 after ultraviolet irradiation.
4 is a graph showing the measurement of UV absorbance of the quantum dots prepared in Examples 1-2, 1-3, 1-4 and 1-6.

The term " C1 ", "C2 ", etc. used in the present invention means a carbon number. For example," C1 to C5 alkyl "means an alkyl group having 1 to 5 carbon atoms.

As used herein, the term "biconstituent nanoclusters" refers to nano-sized compounds in which two kinds of metals are bonded or complexed, and " (S) < / RTI > is bonded or complexed.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a core-shell composite structure quantum dot having the same shape as the schematic diagram shown in FIG. 1, wherein a ZnSe shell is formed on a core doped with a Group 10 element to the AgInS ₂ quantum dot. Is doped in the AgInS ₂ quantum dots to compensate for the surface defects of the quantum dots to make the electrons easier to recombine to prevent the decrease in luminous efficiency. By introducing the ZnSe shell, lattice mismatch with the AgInS ₂ quantum dots can be prevented, The effect of increasing the quantum efficiency can be obtained by reducing the difference.

Further, as shown in FIG. 2, a ZnS shell is further formed outside the ZnSe shell to minimize the defects on the surface, thereby increasing the luminous efficiency and securing the lifetime of the quantum dots. The thickness of the ZnSe shell layer and the thickness of the ZnS shell layer It is possible to adjust the wavelength absorption band by adjusting the thickness.

The core-shell composite structure quantum dot of the present invention includes a core containing a three-dimensional structure nanocluster including silver (Ag), indium (In) and sulfur (S), and a doping material; And a shell containing ZnSe.

The three-dimensional structure nanoclusters may be characterized by an average particle diameter of 2 to 8 nm, preferably an average particle diameter of 2 to 6 nm. The size of the nanoclusters may be a reaction time during production, Composition ratio and so on. At this time, the three-dimensional structure nanoclusters having an average particle diameter of less than 2 nm are not technically easy to manufacture, and when the average particle diameter exceeds 8 nm, there is a problem that the light emitting efficiency is lowered.

After the doping material is doped into the three-dimensional structure nanoclusters, a core is formed. The core preferably has an average particle diameter of 2.1 to 9 nm, preferably 2.5 to 9 nm.

The doping material is easily doped using at least one selected from the group consisting of nickel (Ni), palladium (Pd) and platinum (Pt), preferably at least one selected from nickel and palladium, more preferably nickel .

The average thickness of the shell is preferably 0.2 to 5 nm, preferably 0.2 to 3 nm. If the average thickness of the shell is less than 0.2 nm, there may be a problem that the defect of the surface of the quantum dot core can not be compensated. The lifetime and efficiency of the quantum dots may be reduced, so that it is preferable to have a thickness within the above range.

When the shell is formed of a ZnSe shell layer and a ZnS shell layer, the average thickness ratio of the ZnSe shell layer and the ZnS shell layer is preferably 1: 1 ~ 3. If the average thickness ratio is less than 1: 1, The effect of decreasing the efficiency decreases. When the ratio exceeds 1: 3, there is a problem that the lifetime and the efficiency of the quantum dots decrease. Therefore, it is preferable to have the thickness ratio within the above range.

The quantum dot of the core-shell composite structure of the present invention can absorb light of a wavelength range of 440 to 680 nm, preferably 460 to 500 nm of light blue color, 500 to 530 nm of green color, (yellow color) of 530 to 560 nm, an orange color of 560 to 600 nm, and a red color of 600 to 680 nm.

More specifically, the nanoclusters (hereinafter referred to as cores) doped with a doping material absorb light in a wavelength range of 500 to 680 nm. By forming a ZnS shell in the core, Is blue shifted, so that the wavelength range moves from 460 to 680 nm or the wavelength range becomes wider. As the thickness of the shell increases, the blue shift range tends to become larger. For example, if the core absorbs light of orange and red wavelengths and forms a ZnSe shell, it absorbs light of green and light blue wavelengths. Further, when a ZnS shell layer is further formed on the surface of ZnSe, the effect of making the blue shift larger can be obtained.

[Composition]

Another aspect of the present invention relates to a quantum dot composition of the core-shell composite structure, comprising a binary precursor nanocrystal precursor containing a silver precursor, an indium precursor, a capping agent, a surfactant and an organic solvent; A sulfur (S) precursor; A doping material precursor containing an organic solvent and at least one doping material selected from nickel (Ni), palladium (Pd), and platinum (Pt); And zinc sulfide (ZnSe) precursors.

The silver precursor which is one of the components of the binary structure nanocluster precursor may be at least one selected from the group consisting of silver nitrate, silver stearate and silver acetate, preferably silver nitrate, It is better to use one.

The indium precursor, which is one of the components of the binary structure nanocluster precursor, may be selected from the group consisting of indium hydroxide, indium nitrate hydrate, indium acetate hydrate, indium acetylacetonate Indium acetylacetonate and indium acetate. The use of at least one selected from the group consisting of indium acetate, indium nitrate hydrate and indium acetate hydrate is preferred because of the reaction between indium and the capping agent In terms of ease of operation.

Also, as the binary structure nanocluster precursor component, the capping agent may be prepared by grabbing silver (Ag) and / or indium (In) as shown in the following Formulas 3-1 and 3-2, It binds (or binds) with sulfur (S).

[Formula 3-1]

[Formula 3-2]

[Formula 3-3]

The capping agent may be a compound represented by the following formula (1). To in Chemical Formula 1, as the R ¹ and R ² are, independently, R ¹ and / or R ² each is an alkyl group of C5 ~ C20, preferably R ¹ and / or R ² each are straight-chain of C5 ~ C18 Alkyl group, more preferably each of R ¹ and / or R ² is a straight-chain alkyl group of C 5 to C 16. Wherein R < ¹ ^> and / or R < ^{2 &} Each In the case of an alkyl group of less than C5, the carbon length may be so short that it may be difficult to position the sulfur so that indium and / or silver and sulfur are bound, and in the case of an alkyl group of more than C20 the carbon length is too long, And may have a carbon number within the above range.

[Chemical Formula 1]

In addition, the binary structure nanocluster precursor may include a stabilizer for the reaction and a surfactant serving as a derivative for inducing the reaction. The surfactant may include C10-C16 alkyl thiol, preferably C10 It is preferable to use an alkylthiol of C14. In this case, when an alkylthiol having a carbon number of less than C10 is used, the carbon length may be too short to serve as a stabilizer. When the alkylthiol having a carbon number of more than C16 is used, the carbon length is too long, It is preferable to use an alkylthiol having a carbon number within the above range because there may be a problem that it may act as a steric hindrance that interferes with binding.

The binary structure nanocluster precursor is mixed with the silver (Ag) precursor and the indium precursor at a molar ratio of 1: 3 to 10, preferably 1: 4 to 8, more preferably 1: 4 to 8, 6 molar ratio. If the molar ratio of the silver precursor and the indium precursor is less than 1: 3, the band gap may be reduced. If the molar ratio exceeds 1: 10, the luminous efficiency may decrease. It is preferable to prepare a binary structure precursor of nanoclusters.

Also, The organic solvent may include at least one selected from the group consisting of C12 to C20 alkenes and C8 to C20 carboxylic acids, preferably C15 to C20 It is preferable to use at least one selected from alkenes and C8 to C15 carboxylic acids, more preferably C15 to C20 alkenes.

The sulfur precursor, which is one of the quantum dot compositions of the core-shell composite structure of the present invention, And a primary amine represented by the following general formula (2). The primary amine serves not only to cap the sulfur but also to provide electrons through the coordination of sulfur and coordination to help sulfur bind to indium do.

To in the general formula 2, R ¹ and R ² are independently as, R ¹ and / or R ² each is an alkyl group of C5 ~ C20, preferably straight-chain alkyl group of C5 ~ C18, more preferably a C5 ~ C16 Lt; / RTI > Wherein R < ¹ ^> and / or R < ^{2 &} Each In the case of an alkyl group of less than C5, there may be a problem that the carbon length is too short to serve as a capping agent, and in the case of an alkyl group of more than C20, the carbon length is too long to prevent the reaction of sulfur with indium. It is preferable to have the carbon number within the range.

(2)

The quantum dot composition of the core-shell composite structure of the present invention is characterized in that the silver precursor, the indium precursor and the sulfur precursor (except for the sulfur precursor of the ZnSe precursor) are mixed with the silver precursor, the indium precursor and the sulfur precursor in a molar ratio of 1: 3 to 8: , Preferably in a molar ratio of 1: 3 to 6: 6 to 10, from the viewpoint of re-combination between the metal components.

In the dopant precursor, one of the quantum dot compositions of the core-shell composite structure of the present invention, the organic solvent is at least one selected from the group consisting of C12 to C20 alkenes and C8 to C20 carboxylic acids , And preferably at least one selected from the group consisting of C15 to C20 alkenes and C8 to C15 carboxylic acids, and more preferably C15 to C20 alkenes.

The amount of the doping material precursor used is preferably 1: 0.008 to 0.1, preferably 1: 0.01 to 0.05, in terms of the amount of the silver precursor and the doping material precursor, If the molar ratio is less than 1: 0.008, there may be a problem that the doping of the Group 10 metal does not contribute to the further enhancement of the luminous efficiency. If the molar ratio exceeds 1: 0.1, the Group 10 metal sticks to the indium precursor, There is a problem of falling down. Therefore, it is preferable to use within the above range.

The zinc selenide precursor, which is one of the quantum dot compositions of the core-shell composite structure, is a Zn precursor containing zinc and a C12 to C20 carboxylic acid; And a Se precursor for a shell containing sulfur and a trialkylphosphine represented by the following general formula (3).

(3)

In Formula 3, R ¹ to R ^{3 are} independent, and R ¹ to R ³ Each is a C5 to C12 linear or branched alkyl group, preferably R &^lt; ¹ > to R &^lt; ³ &^gt; Each is a straight-chain alkyl group of C8 to C12.

The ZnSe precursor preferably contains zinc and selenium at a molar ratio of 1: 0.9 to 1.1, preferably 1: 0.95 to 1.05.

In addition, the quantum dot composition of the core-shell composite structure of the present invention can be used as a binary structure nanocrystal precursor when a shell is formed of a ZnSe shell layer and a ZnS shell layer; A doping material precursor; And zinc sulfide (ZnSe) precursors; And a ZnS precursor.

The ZnS precursor is a Zn precursor containing zinc and a C12 to C20 carboxylic acid; And an S precursor for a shell containing sulfur and a trialkylphosphine represented by the following formula (3).

(3)

[Manufacturing method]

Another aspect of the present invention relates to a method of manufacturing a quantum dot of the core-shell composite structure as described above, wherein a binary structure nano cluster is prepared, a sulfur precursor is used to prepare a three- Doped material that is a Group 10 metal to form a core composed of a nanoclust of a three-element structure, i.e., -AgInS ₂ doped with a Group 10 metal. Next, a ZnSe shell may be formed on the outside of the core to form a quantum dot having a composite structure of core and shell.

More specifically, the quantum dots of the core-shell composite structure of the present invention can be prepared by preparing a solution containing a binary structure nano-cluster of indium (In) and silver (Ag); Adding a sulfur (S) precursor to the solution to prepare a solution containing a ternary structure nanocluster; Preparing a solution containing a core doped with nanoparticles and a doping reaction at 110 ° C to 180 ° C after introducing a doping material precursor into a solution containing a nanoparticle and a three-dimensional structure; Introducing and reacting a Zn precursor into a solution containing the core; And a Se precursor solution for a shell, and then reacting to form and grow a ZnSe shell.

As another method, a ZnSe precursor may be added together without separately injecting the Zn precursor and the S precursor for the shell as described above. More specifically, a method for preparing a ZnSe precursor including a binary structure nanoparticle of indium (In) Preparing a solution; Adding a sulfur (S) precursor to the solution to prepare a solution containing a ternary structure nanocluster; Adding a doping material precursor to a solution containing a three-dimensional structure nano-cluster, then growing a doping reaction and nanoparticles at 110 ° C to 180 ° C to prepare a solution containing the core; And forming and growing a ZnSe shell by injecting and reacting a ZnSe precursor into the solution containing the core, thereby forming quantum dots of the core-shell composite structure of the present invention.

Here, the step of preparing the solution containing the binary structure nanoclusters may include a step of removing the excess moisture and oxygen from the mixed solution of the indium precursor, the silver precursor, the capping agent represented by the following formula 2 and the organic solvent at 80 to 100 ° C, ; And a step of adding a surfactant to the mixed solution from which moisture and oxygen have been removed and reacting at 110 to 180 ° C and a nitrogen atmosphere to prepare a solution containing a binary structure nanocluster.

The step of preparing the solution including the three-dimensional structure nanoclusters may be performed at 110 to 180 ° C. and under a nitrogen atmosphere. When the solution is conducted at a temperature lower than 110 ° C., When performed in an atmosphere exceeding 180 ° C, the luminous efficiency is lowered and silver is crystallized and precipitated, which may cause a problem.

In addition, the step of forming and growing the ZnSe shell may be performed at 110 to 180 ° C for 1 to 3 hours.

In addition, the method for manufacturing a quantum dot of the core-shell composite structure of the present invention may further include a step of purifying and cleaning.

The method for fabricating a quantum dot of the core-shell composite structure of the present invention comprises forming and growing a ZnS shell after forming and growing a ZnSe shell when the shell is formed of a ZnSe shell layer and a ZnS shell layer; You can do more.

The step of forming and growing the ZnS shell

Introducing and reacting a Zn precursor into a solution containing a ZnSe shell prepared in the step of forming and growing a ZnSe shell; And an S precursor solution for shell, and then reacting to form and grow a ZnS shell layer; or

Forming and growing a ZnSe shell by injecting and reacting a ZnS precursor into a solution containing a ZnSe shell prepared in the step of forming and growing a ZnSe shell to form a shell layer into two layers, that is, a ZnSe shell layer and a ZnS shell layer .

As described above, the method for manufacturing a quantum dot of the core-shell composite structure of the present invention is not only complicated but also complicated, and its manufacturing conditions are not harsh.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited by the following examples.

[ Example ]

Example One

(1) Preparation of binary structure nano cluster solution

1.05 g (2.5 mmol) of indium acetate in powder state, 0.085 g (0.5 mmol) of silver nitrite, 2.35 ml (7.5 mmol) of oleic acid and 40 ml of 1-octadecine were added to a three- For 1 hour, and then, under the same pressure and temperature, water and oxygen were removed.

Subsequently, the reaction mixture was sufficiently reacted at 90 ° C for 1 hour in a nitrogen atmosphere at 1 atm and then 5 ml (20 mmol) of dodecanethiol was added as a surfactant to the reaction mixture, followed by stirring at 120 ° C for about 1 hour And reacted to prepare a solution containing a binary structure nanocluster.

(2) Preparation of three-dimensional structure nanocluster solution

0.13 g (4 mmol) of sulfur (s) was added to 6.5 ml of oleylamine and stirred to prepare a sulfur precursor.

Next, the sulfur precursor solution was injected into a reactor containing a solution containing a binary structure nanocluster at a nitrogen atmosphere of 1 atm and at 120 ° C, stirred, and reacted to obtain a three-way structure nanocrystal solution .

(3) doping using a doping material precursor

0.003 g (0.01 mmol) of nickel stearate was mixed with 0.5 ml of 1-octadecine, and a nickel precursor solution (doping material precursor) was injected into a reactor containing the three-way structure nanocluster solution. The doping reaction was carried out. Doping reaction core (mean having a 30 min reaction by which after cooling at 25 ℃ performed for 2 it won structure nanoclusters of nickel (Ni) doped with the three-circle structure nanoclusters form of AgInS ₂ to grow a sufficient nanoclusters Particle diameter 3.2 nm) was prepared.

(4) ZnSe Shell formation

1.25 g (2 mmol) of Zn stearate was added to the reactor while the solution containing the core was put in a reactor (or a three-necked flask or the like) at 25 ° C., and the reaction was carried out for about 20 minutes .

Subsequently, 0.158 g (2 mmol) of selenium (Se) and 10 ml (20 mmol) of trioctylphosphine were mixed to prepare a solution of Se precursor, which was then introduced into the reactor, the temperature of the reactor was raised to 120 ° C , Stirring was carried out for 2 hours while maintaining the temperature, and a ZnSe shell (average thickness of 0.5 nm) was grown outside the core. Next, the reactor was lowered to 25 DEG C, and then purified and washed with an excess of anhydrous ethanol together with a small amount of toluene using a centrifugal separator. The quantum dots of the core-shell composite structure were recovered by repeating 2 to 3 times, To obtain quantum dots.

Example 2 ~ Example 6

A core having a composition and an average particle size as shown in Table 1 below was prepared by the same method as in Example 1 to prepare quantum dots of a core-shell composite structure, and Examples 2 to 6 were respectively performed.

Example 7

7Z-tetradecenoic acid represented by the following formula 1-1 was used as a capping agent in the production of a core of a core-shell composite structure in the same manner as in Example 1, except that 7Z-tetradecenoic acid represented by the following formula 1-1 was used.

[Formula 1-1]

In Formula 1-1, R ¹ is a C 5 alkyl group, and R ² is a C4 alkyl group.

Example 8

12Z-eicosanoic acid (12Z-eicosanoic acid) represented by the following formula 1-2 was used as a capping agent in the production of a core of a core-shell composite structure in the same manner as in Example 1.

[Formula 1-2]

In Formula 1-2, R ¹ is a C 12 alkyl group, and R ² is a C 11 alkyl group.

Example 9

(1) Core- ZnSe Shell layer formation

A solution containing a core having a nanocrystal structure of ternary structure doped with nickel (Ni) was prepared in the same manner as in Example 1 above.

Next, 1.25 g (2 mmol) of zinc stearate was put in the reactor while the solution containing the core was put in a reactor (or a three-necked flask or the like) at 25 ° C, The reaction was allowed to proceed.

Next, 0.158 g (2 mmol) of selenium (Se) and 10 ml (20 mmol) of trioctylphosphine were mixed to prepare a Se precursor solution. The precursor solution was added to the reactor and the temperature of the reactor was raised to 120 ° C Thereafter, the ZnSe shell was grown outside the core by stirring and reacting for 2 hours while maintaining the temperature, thereby preparing a solution containing the quantum dots of the core-ZnSe shell structure.

(2) Core- ZnS Shell layer formation

Next, 1.25 g (2 mmol) of zinc stearate was added to the solution containing the quantum dots of the core-ZnSe shell structure, and the reaction was carried out for about 20 minutes.

Next, 0.065 g (2 mmol) of sulfur (S) and 10 ml (20 mmol) of trioctylphosphine were mixed to prepare an S precursor solution, which was then introduced into the reactor, the temperature of the reactor was raised to 120 ° C (Mean particle size: 3.2 nm) -> ZnSe shell layer (average thickness: 0.5 nm) -> ZnS shell layer (average thickness: 0.5 nm) by stirring and reacting for 2 hours while maintaining the temperature, ) Were stacked on the substrate.

Example 10

A quantum dot having a complex structure in which a shell having a two-layer structure was formed was prepared in the same manner as in Example 9, except that 1.75 g (2.8 mmol) of the zinc stearate and 0.117 g (3.6 mmol) of sulfur were used in preparing the ZnS shell layer, A quantum dot having a composite structure in which a core (average particle diameter 3.2 nm) -> a ZnSe shell layer (average thickness: 0.3 nm) -> a ZnS shell layer (average thickness: 0.7 nm)

Comparative Example One

The procedure of Example 1 was followed except that no quantum dots formed only of ZnSe shell and a core of a ternary structure nanocluster type without doping Group 10 metal were prepared by not doping with nickel.

Comparative Example 2 to 3

The core was prepared in the same manner as in Example 1 except that the indium precursor was in a 1: 12 molar ratio and a 1: 1 molar ratio with respect to the silver precursor as shown in the following Table 1 to form a ZnSe shell, And Comparative Example 3, respectively.

Comparative Example 4

The quantum dots of Ni-AgInS ₂ core and ZnSe shell composite structures were prepared in the same manner as in Example 1 except that nickel stearate was used in a molar ratio of 1: 0.005 based on the silver precursor as shown in Table 1 below.

Comparative Example 5

A quantum dot having a complex structure was prepared in the same manner as in Example 1 except that 5Z-decenoic acid represented by the following Formula 1-3 was used as a capping agent in the production of cores.

[Formula 1-2]

In Formula 1-3, R ¹ is an alkyl group of C 4 and R ² is an alkyl group of C 3.

Comparative Example 6.

A solution containing a nickel (Ni) -doped core (average particle diameter: 3 nm) having a nanocrystal structure having a three-dimensional structure was prepared in the same manner as in Example 1, and the solution was separated, purified and washed, The core itself was prepared as a quantum dot.

Comparative Example 7

A solution containing a core having a nanocrystal structure of a three-way structure doped with nickel (Ni) was prepared in the same manner as in Example 1, and then a ZnS shell layer alone layer was formed so as to have an average thickness of 1 nm instead of the ZnSe shell layer.

division core Shell UV absorbance Wavelength Two-dimensional structure
Nanoclusters Three-dimensional structure
Nanoclusters Doping core
all
Particle size Silver precursor
(mmol) Indium precursor
(mmol) Sulfur precursor
(mmol) Average
Particle size Precursor
(Ni, mmol) Average
Particle size Zn and Se
Mole ratio Shell
Average
thickness ZnSe:
ZnS shell layer
Thickness ratio Example
One 0.5 2.5 4 3 nm 0.01 3.2 nm 1: 1 0.5 nm - 535 nm Example
2 0.5 1.5 4 2.5 nm 0.01 2.8 nm 1: 1 0.5 nm - 532 nm Example
3 0.5 4 4 3.3 nm 0.01 3.7 nm 1: 1 0.5 nm - 570 nm Example
4 0.5 2.5 5 3.2 nm 0.01 3.5 nm 1: 1 0.5 nm - 575 nm Example
5 0.5 2.5 4 3 nm 0.008 3.1 nm 1: 1 0.5 nm - 535 nm Example
6 0.5 2.5 4 3 nm 0.07 3.5 nm 1: 1 0.5 nm - 585 nm Example
7 0.5 2.5 4 2.5 nm 0.01 2.7 nm 1: 1 0.5 nm - 530 nm Example
8 0.5 2.5 4 2.8 nm 0.01 3 nm 1: 1 0.5 nm - 620 nm Example
9 0.5 2.5 4 2.5 nm 0.01 3 nm 1: 1 1 nm 1: 1 512 nm Example
10 0.5 2.5 4 2.5 nm 0.01 3 nm 1: 1 1 nm 1: 2.3 498 nm Comparative Example
One 0.5 2.5 4 2.5 nm - - 1: 1 1 nm 530 nm Comparative Example
2 0.5 6 4 3.5 nm 0.01 3.8 nm 1: 1 1 nm 610 nm Comparative Example
3 0.5 0.5 4 1.5 nm 0.01 2 nm 1: 1 1 nm 523 nm Comparative Example
4 0.5 2.5 4 2.5 nm 0.005 2.7 nm 1: 1 1 nm 543 nm Comparative Example
5 0.5 2.5 Formation is not good - - - - - - Comparative Example
6 0.5 2.5 4 2.5 nm 0.01 3 nm - - - 540 nm Comparative Example
7 0.5 2.5 4 2.5 nm 0.01 3 nm 0: 1 1 nm - 530 nm

In Examples 1 to 8 of Table 1, there is a difference in the average grain size of the quantum dots by the composition ratio of silver and indium used in the binary and / or 3-member nano clusters and the amount of nickel used as the doping material, It was confirmed that the emission wavelength was changed with the change. As the particle size of the quantum dots increases, the emission wavelength tends to shift toward the red wavelength. When the shell is formed in the core, it can be seen that it tends to shift about 10 to 30 nm toward the light blue (460 to 500 nm) wavelength, which is comparable to Comparative Example 6 in which the ZnSe shell layer is not provided.

Examples 9 to 10, in which a ZnS shell layer was further formed on the ZnSe shell layer, were found to be 25 to 45 times larger than those of the ZnSe shell layer alone (Example 1) or the ZnS shell layer alone (Comparative Example 7) nm blue shift was better.

Through this, it is possible to control the particle size of the quantum dots by controlling the composition ratio of the material used in the core and the thickness of the shell, and to control the emission wavelength of the quantum dots by controlling the particle size of the quantum dots, It can be confirmed that it can be controlled.

Comparative Example 1 in which the core was not doped with a doping material showed a weaker wavelength intensity than that in Example 1. In the production of the nano clusters of the core structure, the silver precursor and the indium precursor were mixed in a ratio of 1: 10 In the case of Comparative Example 2, compared with Example 3 (1: 8 molar ratio), there was almost no increase in luminescence intensity.

In addition, in the case of Comparative Example 3 in which the silver precursor and the indium precursor were less than 1: 3 molar ratio, the wavelength value was lower than that in Example 1, because the energy band gap was too small.

In addition, in the case of Comparative Example 4 in which the amount of the doping material precursor used was less than 1: 0.008 molar ratio with respect to the silver precursor, the doping amount was too small as compared with Example 1, so that there was no effect of increasing the luminous efficiency by doping. In the case of Comparative Example 5 using a capping agent outside the range suggested by the present invention, the formation of the 3-membered nanocluster was not successful.

Example 1-1 ~ Example 1-8

In the same manner as in Example 1, quantum dots were prepared so as to have the compositions shown in Table 2 below, and Examples 1-1 to 1-8 were carried out. In the production of the three-way structure nanoclusters, The quantum dots were prepared to have average particle diameters as shown in Table 2 below, and then UV spectrophotometer (VARIAN, CARY 100 Conc.) Was performed for 30 seconds, 60 seconds, 90 seconds, 120 seconds, 180 seconds, ). The results are shown in Table 2. < tb > < TABLE > In this case, 0.01 g of each of the quantum dots was taken, dissolved in 3 ml of toluene, placed in a test tube, and the emission spectrum was measured according to UV absorbance.

An image obtained by irradiating the quantum dots of each of Examples 1-1 to 1-7 with ultraviolet rays (UV) having a wavelength of 340 nm is shown in Fig. 3, and Examples 1-2, 1-3, 1-4 and 1 The graph of the measurement of the UV absorbance of the quantum dots prepared at -6 is shown in Fig.

division Two-dimensional structure nano cluster Three-dimensional structure nano cluster Ni - AgInS ₂ Qdot Shell UV absorbance Wavelength Silver precursor
(mmol) Indium precursor
(mmol) Sulfur precursor
Reaction time after injection
(second) Average particle diameter Doped material
Precursor
(Ni, mmol) Average particle diameter Zn and Se
Mole ratio Shell
Average thickness Example
1-1 0.5 2.5 10 2.5 nm 0.01 3 nm 1: 1 0.5 nm 515 nm Example
1-2 0.5 2.5 30 3 nm 0.01 3.2 nm 1: 1 0.5 nm 535 nm Example
1-3 0.5 2.5 60 3.3 nm 0.01 3.5 nm 1: 1 0.5 nm 555 nm Example
1-4 0.5 2.5 90 3.8 nm 0.01 4.2 nm 1: 1 0.5 nm 572 nm Example
1-5 0.5 2.5 120 4.1 nm 0.01 4.3 nm 1: 1 0.5 nm 590 nm Example
1-6 0.5 2.5 180 4.3 nm 0.01 4.5 nm 1: 1 0.5 nm 595 nm Example
1-7 0.5 2.5 300 4.4 nm 0.01 4.6 nm 1: 1 0.5 nm 612 nm Example
1-8 0.5 2.5 600 4.5 nm 0.01 4.7 nm 1: 1 0.5 nm 643 nm

As shown in Table 2, it can be seen that the particle size of the core can be controlled by controlling the reaction time of the binary structure nanocluster and the sulfur precursor in the production of the core, and it is also confirmed that the emission wavelength can be controlled by adjusting the core particle size I could.

It can be confirmed that the wavelength of the UV absorbance can be controlled in accordance with the particle size of the core and the quantum dots. In addition, it can be confirmed that the particle size of the quantum dot can be controlled by controlling the reaction time and the composition ratio. That is, as the particle diameter of the core increases, the value of the UV absorbance light emission wavelength increases, and the ZnSe shell can be formed to shift to the light blue side, and the degree of shift can be controlled by adjusting the thickness of the shell.

Claims

A nanocluster comprising a ternary structure nanoparticle comprising silver (Ag), indium (In) and sulfur (S) and at least one dopant selected from nickel (Ni), palladium (Pd) and platinum A core; And
A shell containing zinc selenide (ZnSe);
Lt; _{RTI ID = 0.0} > Zn-doped < / RTI >

The quantum dots of a Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure according to claim 1, wherein the doping material is nickel.

The quantum dots of a Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure according to claim 1, wherein the three-dimensional structure nanoclusters have an average particle diameter of 2 to 8 nm.

2. The quantum dots of a Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure according to claim 1, wherein the core has an average particle diameter of 2.1 to 9 nm.

The method of claim 1, wherein the shell further comprises zinc sulphide (ZnS)
A quantum dot of a Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure, which comprises a ZnSe shell layer outside the core and a ZnS shell layer outside the ZnSe shell layer.

6. The method of claim 5, wherein the average thickness of the shell is 0.2 to 5 nm, and the average thickness ratio of the ZnSe shell layer and the ZnS shell layer is 1: 1 to 3. The AgInS ₂ core-ZnSe shell composite structure Of the quantum dot.

The quantum dots of a Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure according to any one of claims 1 to 6, characterized in absorbing light in a wavelength range of 440 to 680 nm.

A binary structure nanocluster precursor containing a precursor, an indium precursor, a capping agent, a surfactant and an organic solvent;
A sulfur (S) precursor;
A doping material precursor containing an organic solvent and at least one doping material selected from nickel (Ni), palladium (Pd), and platinum (Pt); And
ZnSe precursor;
Lt; _{RTI ID = 0.0} > 10 < / RTI > metal doped AgInS ₂ core-ZnSe shell composite structure.

The method of claim 8, further comprising: a ZnS precursor; wherein the ZnS precursor is
A Zn precursor containing zinc and a C12 to C20 carboxylic acid; And
AgInS ₂ -ZnSe quantum dot core composition of the shell composite structure of a Group 10 metal, characterized in that it comprises a doped; sulfur and shell S to a precursor containing a trialkylphosphine represented by the general formula (3).
(3)

The method of claim 8, wherein the capping agent
A quantum dot composition of a Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure, which is a compound represented by the following Chemical Formula 1;
[Chemical Formula 1]

9. The composition of claim 8, wherein the surfactant comprises
A quantum dot composition of a Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure, characterized by comprising C10-C16 alkyl thiol.

The method of claim 8, wherein the sulfur precursor
sulfur; And
A primary amine represented by the following general formula (2);
A quantum dot composition of a Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure;
(2)

9. The method of claim 8, wherein the organic solvent of the binary structured nanocluster precursor and the organic solvent of the doping material precursor are independent and each of the organic solvents is selected from C12 to C20 alkenes and C8 to C20 carboxylic acids A quantum dot composition of a Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure, characterized by containing at least one Group III metal-doped AgInS ₂ core-ZnSe shell composite structure.

9. The method according to claim 8, wherein the binary structure nanocluster precursor comprises a Group 1 metal-doped AgInS ₂ core-shell structure, wherein the Ag structure comprises a silver (Ag) precursor and an indium (In) precursor in a molar ratio of 1: Quantum dot composition of ZnSe shell composite structure.

The quantum dot composition of Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure according to Claim 8, wherein the composition comprises a silver precursor, an indium precursor and a sulfur precursor in a molar ratio of 1: 3 to 8: 5 to 12.

The method of claim 8, wherein the ZnSe precursor
A Zn precursor containing zinc and a C12 to C20 carboxylic acid; And
A Se precursor containing sulfur and a trialkylphosphine represented by the following general formula (3);
Lt; _{RTI ID = 0.0} > 10 < / RTI > metal doped AgInS ₂ core-ZnSe shell composite structure.
(3)

The method of claim 17, wherein the ZnSe precursor is
Zinc and selenium in a molar ratio of 1: 0.9 to 1.1. 10. The quantum dot composition of Group 10 metal-doped AgInS ₂ core-ZnSe shell composite structure.

Preparing a solution including a binary structure nanocluster of indium (In) and silver (Ag);
Adding a sulfur (S) precursor to the solution to prepare a solution containing a ternary structure nanocluster;
Introducing a doping material precursor into a solution containing a ternary structure nano cluster, growing a doping reaction and nanoparticles at 110 to 180 ° C to prepare a solution containing the core;
Introducing and reacting a Zn precursor into a solution containing the core; And
Se precursor solution and then reacting to form and grow a ZnSe shell;
Wherein the Ag-doped Group-III metal-doped AgInS ₂ core-ZnSe-shell composite structure is formed of a Group 10 metal-doped AgInS ₂ core-ZnSe-shell composite structure.

Claim 19 according to any of, and growth steps of the ZnS shell of claim 20, wherein; method of producing a more containing a Group 10 metal, characterized in that the doping of the core ₂ AgInS -ZnSe shell of the composite quantum dot structure, a.

21. The method according to claim 19 or 20, wherein the step of preparing a solution comprising the binary structure nanoclusters
Removing excess water and oxygen from a mixed solution of an indium precursor, a silver precursor, a capping agent represented by the following Chemical Formula 2 and an organic solvent at 80 to 100 캜; And
Preparing a solution containing a binary structure nanocluster by introducing and reacting a surfactant into a mixed solution from which water and oxygen have been removed under a nitrogen atmosphere at 110 to 180 ° C;
Wherein the Ag-doped Group-III metal-doped AgInS ₂ core-ZnSe-shell composite structure is formed of a Group 10 metal-doped AgInS ₂ core-ZnSe-shell composite structure.

21. The method of claim 19 or 20, wherein the step of preparing the solution including the three-dimensional structure nanoclusters is performed at 110 to 180 DEG C and under a nitrogen atmosphere. The Group 10 metal-doped AgInS ₂ core-ZnSe (Method for manufacturing quantum dots of shell composite structure).

21. The method of claim 19 or 20, wherein forming and growing the ZnSe shell further comprises:
Under 110 to 180 ℃, 1 ~ of the Group 10 metal, characterized in that to perform for three hours AgInS ₂ doped core -ZnSe method of manufacturing a quantum dot of the shell composite structure.