WO2020085174A1 - Perovskite nano-crystal thin film, method for producing perovskite nano-crystal thin film, light-emitting element, photoelectric conversion element, display device, and electronic device - Google Patents

Perovskite nano-crystal thin film, method for producing perovskite nano-crystal thin film, light-emitting element, photoelectric conversion element, display device, and electronic device Download PDF

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WO2020085174A1
WO2020085174A1 PCT/JP2019/040788 JP2019040788W WO2020085174A1 WO 2020085174 A1 WO2020085174 A1 WO 2020085174A1 JP 2019040788 W JP2019040788 W JP 2019040788W WO 2020085174 A1 WO2020085174 A1 WO 2020085174A1
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perovskite
thin film
nanocrystals
ligand
perovskite nanocrystal
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ヴァスデヴァン ピライ ビジュ
スーシャント ギミリ
ラタ チョウハン
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国立大学法人北海道大学
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    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
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Definitions

  • the present invention relates to a perovskite nanocrystal thin film, a method for manufacturing a perovskite nanocrystal thin film, a light emitting element, a photoelectric conversion element, a display device, and an electronic device, for example, a light emitting diode using a lead halide perovskite nanocrystal thin film, a solar cell, and light detection. It is suitable for application to elements, display devices, and the like.
  • Perovskites are excellent in that they can be easily synthesized from inexpensive precursors, have a wide range of emission colors, can obtain narrow-band photoluminescence (PL), and have a large diffusion length of photogenerated charge carriers. It has optical and electrical properties. For this reason, development of solar cells, lasers, light emitting diodes (LEDs), and the like using quantum dots made of perovskite nanocrystals is underway (see, for example, Patent Documents 1 to 3).
  • perovskite nanocrystals When quantum dots using perovskite nanocrystals are applied to solar cells, LEDs, etc., it is thought that if a thin film in which perovskite nanocrystals are arranged can be used, the structure and manufacturing of solar cells, LEDs, etc. will be simplified, which is desirable. .
  • the problem to be solved by the present invention is to use as a quantum dot array, a perovskite nanocrystal thin film in which perovskite nanocrystals are arranged, and a manufacturing method capable of easily producing such a perovskite nanocrystal thin film.
  • Another object of the present invention is to provide a light emitting device, a photoelectric conversion device, a display device and an electronic device using the perovskite nanocrystal thin film.
  • the ligand that binds the perovskite nanocrystals to each other is appropriately selected according to the set distance between the perovskite nanocrystals.
  • the ligand may be monodentate or multidentate, such as bidentate.
  • the length of the ligand is generally selected to be 3.7 nm or less from the viewpoint of obtaining the interaction between the perovskite nanocrystals bound by the ligand.
  • the lower limit of the length of the ligand is not particularly limited, but the length of the ligand is generally 0.87 nm or more.
  • oleic acid CH 3 (CH 2 ) 7 CH ⁇ CH (CH 2 ) 7 COOH
  • the length of these ligands is used.
  • this perovskite nanocrystal thin film is not particularly limited, and it can be used for various devices using a quantum dot array, but preferably, a light emitting layer that emits light by light irradiation or current injection, or a current or voltage by light irradiation. Used as a photoelectric conversion layer capable of taking out. If necessary, a plurality of layers of the same or different perovskite nanocrystal thin films may be laminated and used.
  • the emission color can be controlled by selecting A, B, and X forming ABX 3 and a ligand that determines the distance between the perovskite nanocrystals. .
  • A, B, X and the ligand that compose ABX 3 are selected according to the emission color.
  • the size of the perovskite nanocrystal is selected according to need, but is generally 5 nm or more and 15 nm or less, and typically 8 nm or more and 12 nm or less.
  • the distance between the perovskite nanocrystals is generally 2 nm or more and 5 nm or less, but is not limited thereto.
  • the shape of the perovskite nanocrystal is not particularly limited, but is generally cubic.
  • a perovskite nanocrystal thin film comprising a perovskite nanocrystal represented by: Attaching a solution in which the perovskite nanocrystals bound with the ligand are dispersed in a solvent to a substrate, Drying the solution attached to the substrate to self-assemble the perovskite nanocrystals bound with the ligand to form a thin film of the perovskite nanocrystals bound to each other via the ligand.
  • a method for producing a characteristic perovskite nanocrystal thin film is
  • the concentration of the solution in which the ligand-bound perovskite nanocrystals are dispersed in the solvent is too low, it is difficult to obtain a thin film composed of perovskite nanocrystals bound to each other via the ligand. Therefore, the concentration is preferably larger than 0.5 mg / mL. On the other hand, if it is too high, ligand-bound perovskite nanocrystals may aggregate, so it is preferably selected at 1.5 mg / mL or less.
  • An aprotic solvent is preferably used as the solvent in which the perovskite nanocrystals to which the ligand is bound are dispersed.
  • the aprotic solvent is, for example, toluene, hexane, dichloroethylene, trichloroethylene, chloroform, chlorobenzene, dichlorobenzene, styrene, dimethylformamide, dimethylsulfoxide, xylene, cyclohexene, isopropyl alcohol and the like.
  • the perovskite nanocrystal to which the ligand is bound can be formed by various methods, and the forming method is selected as necessary.
  • AX, BX 2 , Y— (CH 2 ) n —NH 2 and oleic acid are dissolved in a solvent to prepare a precursor solution, and a ligand is bound from the precursor solution.
  • the perovskite nanocrystals to which the ligand is bound are formed.
  • a solvent for dissolving AX, BX 2 , Y- (CH 2 ) n- NH 2 and oleic acid for example, N-dimethylformamide (DMF) is used, but it is not limited thereto.
  • DMF N-dimethylformamide
  • the precursor solution is mixed with another solvent different from the solvent of the precursor solution, and the perovskite nanocrystals to which the ligand is bound are precipitated therefrom.
  • the aprotic solvent described above is preferably used.
  • the light emitting element is a light emitting diode or a laser, and electrodes are provided on both sides of the perovskite nanocrystal thin film that constitutes the light emitting layer (active layer in laser), and light emission is caused by passing an electric current between these electrodes.
  • the photoelectric conversion element is, for example, a solar cell, a light detection element (photodiode, etc.), or the like.
  • the display device is used for an electronic device such as a television, a monitor for PC, a digital camera, a digital video camera, a smartphone, or a part thereof.
  • the electronic device may be basically any type, and includes both a portable type and a stationary type, but specific examples thereof are a mobile phone, a mobile device, a robot, and a personal computer. , In-vehicle equipment, various home appliances, etc.
  • the perovskite nanocrystal thin film when used as the photoelectric conversion layer, the electric power obtained by using the photoelectric conversion layer can be used in the electronic device.
  • the perovskite nanocrystal thin film can be used for display in this display device.
  • this perovskite nanocrystal thin film can be used as a quantum dot array in which quantum dots made of perovskite nanocrystals are arranged.
  • this perovskite nanocrystal thin film as a photoelectric conversion layer of a photoelectric conversion element, not only highly efficient photoelectric conversion can be performed but also high light durability can be obtained. As described above, a high-performance light emitting element, photoelectric conversion element, display device, and electronic device can be realized.
  • FIG. 1 is a schematic diagram showing a perovskite nanocrystal thin film according to a first embodiment of the present invention.
  • FIG. 3 is a schematic diagram showing a ligand-bonded perovskite nanocrystal used for manufacturing the perovskite nanocrystal thin film according to the first embodiment of the present invention.
  • FIG. 3 is a schematic diagram showing a solution in which a perovskite nanocrystal having a ligand bound thereto is dispersed, which is used for manufacturing a perovskite nanocrystal thin film according to the first embodiment of the present invention.
  • 3 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of MAPbBr 3 perovskite nanocrystals produced in Example 1.
  • FIG. 3 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of FAPbBr 3 perovskite nanocrystals produced in Example 3.
  • FIG. 5 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of CsPbBr 3 perovskite nanocrystals produced in Example 2.
  • FIG. 3 is a schematic diagram showing PL attenuation profiles of MAPbBr 3 perovskite nanocrystals, FAPbBr 3 perovskite nanocrystals and CsPbBr 3 perovskite nanocrystals in a colloidal solution.
  • MAPbBr 3 perovskite nanocrystals in the colloidal solution is a schematic diagram for explaining a method of determining the band gap of the FAPbBr 3 perovskite nanocrystals and CsPbBr 3 perovskite nanocrystals.
  • 5 is a drawing-substituting photograph showing a transmission electron microscope image of the MAPbBr 3 perovskite nanocrystals produced in Example 1.
  • MAPbBr 3 perovskite nanocrystals prepared in Example 1 is a schematic diagram illustrating a powder X-ray diffraction pattern of CsPbBr 3 perovskite nanocrystals prepared in FAPbBr 3 perovskite nanocrystals and Example 2 produced in Example 3.
  • 5 is a schematic diagram showing a method of manufacturing the MAPbBr 3 perovskite nanocrystal thin film manufactured in Example 1.
  • FIG. 6 is a drawing-substituting photograph showing a photograph of a MAPbBr 3 perovskite nanocrystal thin film produced in Example 1, under a UV lamp.
  • FIG. 7 is a drawing-substituting photograph showing a change in amplified radiation when the intensity of incident photon flux on the MAPbBr 3 perovskite nanocrystal thin film produced in Example 1 is increased.
  • 5 is a schematic diagram showing a change in PL spectrum when the laser fluence of the MAPbBr 3 perovskite nanocrystal thin film produced in Example 1 is changed.
  • FIG. 5 is a schematic diagram showing a change in PL attenuation profile when the laser fluence on the MAPbBr 3 perovskite nanocrystal thin film produced in Example 1 is changed.
  • FIG. 5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed.
  • FIG. 5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed.
  • FIG. 5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed.
  • FIG. 5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed.
  • FIG. 5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed.
  • FIG. 5 is a schematic diagram showing a semi-logarithmic plot of the average PL lifetime and the number of photons measured when the laser fluence of the MAPbBr 3 perovskite nanocrystal thin film produced in Example 1 was changed.
  • 6 is a schematic diagram showing a semi-logarithmic plot of the average PL lifetime and the number of photons measured when the laser fluence on the FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 was changed.
  • FIG. 5 is a schematic diagram showing a semilogarithmic plot of the average PL lifetime and the number of photons measured when the laser fluence on the CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 was changed.
  • FIG. 4 is a schematic diagram showing diffusion and recombination of charge carriers in a perovskite nanocrystal thin film at low laser fluence.
  • FIG. 6 is a schematic diagram showing diffusion and recombination of charge carriers in a perovskite nanocrystal thin film at high laser fluence. It is an approximate line figure showing the method of performing time resolved PL measurement, when the irradiation field of a perovskite nanocrystal thin film is not masked.
  • FIG. 5 is a schematic diagram showing integrated PL spectra from a non-irradiated region and an irradiated region of a FAPbBr 3 perovskite nanocrystal thin film manufactured in Example 3 under a low laser fluence.
  • 6 is a schematic diagram showing a change in PL spectrum when the density of perovskite nanocrystals of the FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed.
  • FIG. 5 is a schematic diagram showing a change in PL attenuation profile when the density of perovskite nanocrystals of the FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed.
  • FIG. 5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 is changed.
  • FIG. 5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 is changed.
  • FIG. 5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 is changed.
  • FIG. 5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 is changed.
  • FIG. 5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 is changed.
  • FIG. 7 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of MAPbI 3 perovskite nanocrystals produced in Example 4.
  • FIG. 6 is a schematic diagram showing a PL spectrum of a colloidal solution of MAPbI 3 perovskite nanocrystals immediately after synthesis prepared in Example 4 and a PL spectrum of a colloidal solution of MAPbI 3 perovskite nanocrystals after 2 months from the synthesis.
  • FIG. 7 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of MAPbCl 3 perovskite nanocrystals produced in Example 5.
  • FIG. 5 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of MAPbBr 3 perovskite nanocrystals produced in Example 5.
  • FIG. 5 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of MAPbI 3 perovskite nanocrystals produced in Example 5.
  • FIG. It is a perspective view which shows the light emitting diode by the 2nd Embodiment of this invention.
  • FIG. 1 shows a perovskite nanocrystal thin film according to the first embodiment.
  • the perovskite nanocrystal thin film has a plurality of chemical formulas ABX 3 (A, B, and X are as described above) that are bound to each other via a ligand 10 and are arranged in a two-dimensional or three-dimensional manner. It consists of the perovskite nanocrystals 20 represented.
  • FIG. 1 the case where the perovskite nanocrystals 20 are two-dimensionally arranged is shown.
  • One perovskite nanocrystal 20 constitutes a quantum dot, and thus this perovskite nanocrystal thin film constitutes a quantum dot array.
  • the perovskite nanocrystal 20 may have a shape other than a cube, such as a rectangular parallelepiped, a sphere, or an ellipsoid.
  • the distance between two adjacent perovskite nanocrystals 20 is determined by the length of the ligand 10.
  • the size (length of one side) of the perovskite nanocrystal 20 is generally 5 nm or more and 15 nm or less, and typically 8 nm or more and 12 nm or less.
  • the distance between the perovskite nanocrystals 20 is generally 2 nm or more and 5 nm or less.
  • This perovskite nanocrystal thin film can generate photoluminescence (PL) by performing light irradiation and can be used as a light emitting layer.
  • the emission color of this perovskite nanocrystal thin film can be selected by selecting A, B, X in ABX 3 constituting the perovskite nanocrystal 20, the size of the perovskite nanocrystal 20, the molecule used as the ligand 10, and the like. The method of selecting the emission color will be described more specifically.
  • ABX 3 specifically, for example, Cl as X, given the Br ABCl 3-n Br n, consider Br, an I as X when ABBr 3-n I n.
  • a perovskite nanocrystal 20 to which a ligand 10 (Y— (CH 2 ) n —NH 2 10a and oleic acid 10b) is bound is prepared.
  • a precipitation method, a hot injection method, or the like can be used for the production.
  • AX and BX 2 are used as a raw material of perovskite nanocrystals.
  • AX, BX 2 , Y— (CH 2 ) n —NH 2 and oleic acid are dissolved in a solvent such as DMF and stirred to prepare a precursor solution.
  • the precursor solution thus prepared is mixed with another solvent such as anhydrous toluene and stirred to precipitate the perovskite nanocrystals 20.
  • another solvent such as anhydrous toluene and stirred to precipitate the perovskite nanocrystals 20.
  • the ligand 10 is bound to the perovskite nanocrystal 20.
  • the perovskite nanocrystals 20 bound with the thus-deposited ligand 10 are washed to remove the unbound ligand 10.
  • the perovskite nanocrystals 20 to which the ligand 10 is bound are dispersed in a solvent such as toluene, and this dispersion is attached onto a substrate and dried.
  • This dispersion is schematically shown in FIG. 3 (solvent is not shown).
  • the perovskite nanocrystals 20 in the dispersion are arranged by self-assembly, and a perovskite nanocrystal thin film is obtained as shown in FIG.
  • the length of the ligand 10 determines the distance between the perovskite nanocrystals 20.
  • the formation of the perovskite nanocrystal thin film by self-assembly of the perovskite nanocrystals 20 to which the ligands 10 are bound is promoted by the hydrophobic interaction between the ligands 10.
  • the perovskite nanocrystal 20 when the perovskite nanocrystal 20 has a cubic shape of 10 nm ⁇ 10 nm ⁇ 10 nm, when green light emission is obtained, the perovskite nanocrystal 20 may be made of ABBr 3 , and ABr + BBr 2 is used as a raw material thereof. it can. Further, when red light emission is obtained, the perovskite nanocrystal 20 may be made of ABI 3 , and AI + BI 2 can be used as a raw material thereof. Further, when violet emission is obtained, the perovskite nanocrystal 20 may be made of ABCl 3 , and ACl + BCl 2 can be used as a raw material thereof.
  • Example 1 A MAPbBr 3 (Methylammonium Lead Bromide, CH 3 NH 3 PbBr 3 ) perovskite nanocrystal thin film was prepared as follows.
  • MAPbBr 3 perovskite nanocrystals were synthesized by a precipitation method.
  • CH 3 NH 3 Br 28 mg, 0.25 mmol
  • PbBr 2 100 mg, 0.25 mmol
  • oleic acid 80 ⁇ L, 0.25 mmol
  • hexadecylamine 46 mg, 0.19 mmol
  • the solution was dissolved by repeating stirring and heating alternately until a transparent precursor solution was formed on a water bath set at 60 ° C.
  • the transparent precursor solution thus obtained was poured into 50 mL of anhydrous toluene and vigorously stirred.
  • the solution first changed from colorless to green, gradually became cloudy with mixing, and exhibited an orange-yellow color, indicating that MAPbBr 3 perovskite nanocrystals were precipitated.
  • the resulting product was centrifuged at 10,000 rpm for 5 minutes and the clear supernatant was discarded.
  • the precipitate was washed with n-butanol to remove excess unbound ligand.
  • the final precipitate was ultrasonically dispersed again in toluene and centrifuged at 5000 rpm for 5 minutes to separate large particles.
  • a room temperature drop molding technique was used to form a thin film on a glass substrate using the MAPbBr 3 perovskite nanocrystals synthesized as described above. That is, the synthesized MAPbBr 3 perovskite nanocrystals were dispersed in toluene to prepare a concentrated colloidal solution of perovskite nanocrystals (1 mg / mL), which was formed on a slide glass of size 24 ⁇ 50 mm 2 in the atmosphere. 50 ⁇ L of this concentrated colloidal solution was injected into the circular hole formed in the center of the square silicone rubber, and dried to form a MAPbBr 3 perovskite nanocrystal thin film.
  • Example 2 A CsPbBr 3 (Cesium Lead Bromide) perovskite nanocrystal thin film was prepared as follows.
  • CsPbBr 3 perovskite nanocrystals were synthesized by the hot injection method.
  • PbBr 2 (690 mg, 1.88 mmol), oleic acid (4 mL), hexadecylamine (3.670 g) and 1-hexadecene (90 mL) were placed in a 500 mL two-necked flask and dried in vacuum at 120 ° C. for 1 hour. did.
  • cesium acetate (96 mg, 0.5 mmol) in 1-hexadecene (10 mL) was also dried at 120 ° C. in vacuum.
  • To the above solution was added 1 mL of oleic acid to completely dissolve the cesium salt.
  • the argon was repeatedly discharged in vacuum every 20 minutes during drying. After complete dissolution of the lead salt, the temperature was raised to 170 ° C. in an argon atmosphere. A dry cesium acetate solution was injected into the hot solution under argon. After 5 seconds, the reaction was quenched by placing the reaction mixture in an ice-water bath. The reaction mixture was centrifuged at 6000 rpm for 25 minutes and the yellow supernatant was discarded. The precipitate was collected and washed with hexane and n-butanol.
  • FAPbBr 3 perovskite nanocrystals were synthesized by the method described in Non-Patent Document 1. That is, the precursors, formamidinium bromide (0.20 mmol) and lead (II) bromide (0.12 mmol), were separately dissolved in dry DMF. These solutions are called precursor solution A and precursor solution B, respectively. Similarly, octyl ammonium bromide (0.12 mmol) and oleic acid (0.6 mmol) as ligands were dissolved in octadecene (ligand solution) at 80 ° C. with continuous stirring. Precursor solutions A and B were added to these ligand solutions. FAPbBr 3 perovskite nanocrystals were precipitated by adding dry acetone to the mixture of the ligand and the precursor. The mixture was centrifuged at 7000 rpm for 10 minutes and the supernatant was discarded.
  • FAPbBr 3 perovskite nanocrystal thin film was prepared in the same manner as in Example 1.
  • Example 4 A MAPbI 3 (Methylammonium Lead Iodide, CH 3 NH 3 PbI 3 ) perovskite nanocrystal thin film was prepared as follows.
  • MAI Metal Iodide
  • PbI 2 ⁇ -butyrolactone
  • GBL ⁇ -butyrolactone
  • hexadecylamine and oleic acid were dissolved in toluene and kept at 80 ° C. with continuous stirring to prepare a monodentate ligand solution.
  • the amounts of precursor, ligand and solvent used are as follows.
  • the precursor solution thus obtained was rapidly injected into the ligand solution, and the mixture was kept at 80 ° C. for 15 minutes with continuous stirring to carry out the reaction.
  • the solution turned dark brown after the precursor addition, indicating that MAPbI 3 perovskite nanocrystals had precipitated.
  • This mixture was centrifuged at 7000 rpm for 3 minutes, and the residue and supernatant were collected and evaluated.
  • MAPbI 3 perovskite nanocrystals synthesized as described above were dispersed in toluene to prepare a colloidal solution of MAPbI 3 perovskite nanocrystals.
  • This colloidal solution was spin-coated on a slide glass at 500 rpm and then dried to prepare a MAPbI 3 perovskite nanocrystal thin film.
  • X Cl
  • MAX and PbX 2 were mixed in a mixed solvent of 250 ⁇ L DMF and 250 ⁇ L dimethylsulfoxide (DMSO) to prepare a transparent precursor solution.
  • DMSO dimethylsulfoxide
  • 1,12-dodecanedioic acid and 1,12-diaminododecane were dissolved in 500 ⁇ L of DMF to prepare a bidentate ligand.
  • a solution was made.
  • the amounts of precursor, ligand and solvent used are as follows.
  • a MAPbX 3 perovskite nanocrystal thin film was prepared in the same manner as in Example 4.
  • MAPbBr 3 perovskite nanocrystals FAPbBr 3 perovskite nanocrystals and CsPbBr synthesized as described above by ultraviolet-visible (UV-Vis) absorption and PL spectroscopy, transmission electron microscopy, powder X-ray diffraction and time-resolved PL measurement.
  • UV-Vis ultraviolet-visible
  • UV-Vis absorption spectra were recorded using Thermo Fischer Scientific using a colloidal solution in which the synthesized perovskite nanocrystals were dispersed in toluene.
  • the PL spectrum was recorded using a fluorescence spectrometer (FL4100) manufactured by Hitachi, Ltd. using the same colloidal solution. During the measurement of the PL spectrum, the colloidal solution was excited with light having a wavelength of 365 nm.
  • As the transmission electron microscope HD-2000 transmission electron microscope manufactured by Hitachi, Ltd. with an acceleration voltage of 200 kV was used.
  • the sample for observation was prepared by dispersing the synthesized perovskite nanocrystals in toluene, centrifuging at 5000 rpm for 5 minutes to remove large particles, and dropping the supernatant onto a STEM Cu100P grid, followed by vacuum molding. It was made by drying.
  • the powder sample was prepared by grinding the precipitate of perovskite nanocrystals in a mortar.
  • the excitation source used for the time-resolved PL measurement was a 400 nm (150 fs) pulse generated from an SHG crystal of an optical parametric amplifier (Coherent OPA9400).
  • the OPA was pumped at 200 kHz by a regenerative amplifier (Coherent RegA 9000) using a mode-locked Ti: sapphire laser (Coherent Mira 900F) as a seed laser.
  • the fluorescence lifetime system is a combination of a polychromator (Chromex, model250IS) and a photon measuring streak camera (Hamamatsu Photonics, model C4334).
  • the fluorescence signal from the sample was passed through a 440 nm low-pass filter, focused on the entrance slit of the polychromator, and detected using a streak camera.
  • the laser power was modulated using neutral filters with different transmissions.
  • Example CsPbBr 3 perovskite nanocrystals made with 2 3 shows a UV-Vis absorption spectrum and a PL spectrum of a colloidal solution in which is dispersed in toluene.
  • FIG. 7 shows the PL decay profiles of these colloidal solutions.
  • MAPbBr 3 perovskite nanocrystals of these colloidal solution CsPbBr 3 perovskite nanocrystals and FAPbBr 3 perovskite nano these MAPbBr 3 perovskite nanocrystals a band gap of the crystal
  • the Tauc plot of CsPbBr 3 perovskite nanocrystals and FAPbBr 3 perovskite nanocrystals It was decided by carrying out. That is, the bandgap is given by the energy value on the x-axis corresponding to the intersection obtained by extrapolation of the Tauc plot at the sharp edge, as shown in FIG.
  • MAPbBr 3 perovskite nanocrystals derived from the absorption spectra of CsPbBr 3 perovskite nanocrystals and FAPbBr 3 perovskite nanocrystals.
  • the resulting band gap, FAPbBr 3 perovskite nanocrystals, MAPbBr 3 respectively perovskite nanocrystals and CsPbBr 3 perovskite nanocrystals, 2.18eV, was 2.22eV and 2.36 eV.
  • FIG. 9 shows a transmission electron microscope image of MAPbBr 3 perovskite nanocrystals. From FIG. 9, cubic nanocrystals having a clearly uniform size distribution (about 10 nm) are observed.
  • FIG. 10 shows a powder X-ray diffraction pattern. From this powder X-ray diffraction pattern, the synthesized MAPbBr 3 perovskite nanocrystals, FAPbBr 3 perovskite nanocrystals and CsPbBr 3 perovskite nanocrystals can be classified into the cubic system of the space group Pm3m.
  • MAPbBr 3 perovskite nano crystal thin film was formed on a glass substrate. That is, as shown in FIG. 11A, a square silicone rubber having a circular well-shaped hole at the center was formed on a slide glass. Then, 50 ⁇ L of a perovskite nanocrystal solution (1 mg / mL) prepared by dispersing MAPbBr 3 perovskite nanocrystals in toluene was injected into the hole of the silicone rubber, and a cover glass (not shown) was placed thereon. After covering, it was dried.
  • a perovskite nanocrystal solution (1 mg / mL) prepared by dispersing MAPbBr 3 perovskite nanocrystals in toluene was injected into the hole of the silicone rubber, and a cover glass (not shown) was placed thereon. After covering, it was dried.
  • FIG. 11B is a photograph of a MAPbBr 3 perovskite nanocrystal thin film taken under an ultraviolet lamp (UV lamp). It was observed that the whole circular MAPbBr 3 perovskite nanocrystal thin film emitted green light.
  • UV lamp ultraviolet lamp
  • the MAPbBr 3 perovskite nanocrystal thin film formed on the slide glass was photoexcited with a femtosecond laser of 400 nm to investigate the behavior.
  • the fluence (energy per unit area) of the incident laser beam was systematically increased from 0.017 MWcm -2 to 170 MWcm -2.
  • FIG. 12 it was observed that the intensity of green light emission gradually increased as the incident photon flux increased.
  • this increase was recorded as a change in PL spectrum depending on the incident photon flux of the MAPbBr 3 perovskite nanocrystal thin film.
  • the laser fluence-dependent increase in PL intensity indicates an increase in the concentration of charge carriers or electron-hole (eh) pairs generated by light irradiation and the rate of radiative recombination.
  • radiative recombination becomes the dominant process, which is evidenced by amplified radiation above a threshold power of approximately 2 MWcm -2 (see Figures 13 and 16-18).
  • Amplified emission is due to an increase in carrier density between perovskite nanocrystals and an increase in the rate of non-geminate radiative recombination between accumulated carriers. Narrowing of the spectrum or lasing is not observed here due to the collective excitation of the nanocrystals.
  • Fluorescence masking and non-masking experiments were performed to verify the above mechanism of incident photon flux controlled charge carrier accumulation in perovskite nanocrystalline thin films. This experiment was performed using a designed and assembled device for performing time-resolved PL measurements by collecting photons generated from selected areas. As shown in FIG. 20A, during the unmasked experiment, photons were collected from the central iris-controlled irradiation area (radius about 50 ⁇ m). On the other hand, as shown in FIG. 20B, during the masking experiment, the central irradiation area (width: 75 ⁇ m) was masked with black paper mounted on a slide glass, and photons generated from the outer non-irradiation area were collected. .
  • the time-resolved PL measurement of the FAPbBr 3 perovskite nanocrystal thin film was performed, as shown in FIG. 19A and FIG. Was selectively collected.
  • FAPbBr 3 perovskite by controlling the concentration of the colloidal solution of nanocrystals, dense FAPbBr 3 perovskite nano crystal thin film and density of four different low density FAPbBr 3 perovskite A nanocrystal thin film was prepared.
  • the concentration of the colloidal solution used to prepare the high-density FAPbBr 3 perovskite nanocrystal thin film was 1 mg / mL
  • the concentration of the colloidal solution used to prepare the low-density FAPbBr 3 perovskite nanocrystal thin film was 0 in order from the highest density.
  • FIG. 24 shows PL spectra of these high-density FAPbBr 3 perovskite nanocrystal thin films and low-density FAPbBr 3 perovskite nanocrystal thin films.
  • FAPbBr 3 perovskite PL spectrum of a low density low density FAPbBr 3 perovskite nanocrystals films of the nanocrystals is always shifted to a higher energy side, but, FAPbBr 3 perovskite nano dense density FAPbBr 3 crystals
  • the PL spectrum of the perovskite nanocrystal thin film always shifts to the low energy side.
  • the corresponding PL decay profile is shown in FIG.
  • the red-shifted PL spectrum is always accompanied by an increase in PL lifetime.
  • 26A, 26B, 26C and 26D show changes in the time-spectral resolved photon measurement map when the laser fluence of the CsPbBr 3 perovskite nanocrystal thin film prepared in Example 2 was changed to 4 levels.
  • CsPbBr 3 perovskite nano PL lifetime with increasing incident laser fluence to the crystal thin film is reduced, PL intensity increases, which is consistent with PL characteristics of MAPbBr 3 perovskite nano crystal thin film and FAPbBr 3 perovskite nano crystal thin film
  • the maximum PL lifetime (50 ns) estimated for CsPbBr 3 perovskite nanocrystal thin films is two orders of magnitude lower than for inorganic-organic perovskites.
  • A-site cations such as Cs + , MA + or FA + , that occupy the voids formed by the PbBr 6 4- octahedron sharing the apex on the modulation of the minimum of the conduction band of perovskite nanocrystals is unknown, The relationship of cations to PL lifetime has not been clarified.
  • CsPbBr 3 it perovskite nano crystal thin film of short life enough unexpected compared to MAPbBr 3 perovskite nano crystal thin film and FAPbBr 3 perovskite nano crystal thin film of life,
  • a site organic cation MA + or FA + is, perovskite nano It suggests that it is preferable for diffusion of charge over a wide range in the crystalline thin film.
  • the MAPbI 3 perovskite nanocrystals produced in Example 4 were evaluated by the same UV-Vis absorption and PL spectroscopy as described above. Therefore, a colloidal solution was prepared in which the MAPbI 3 perovskite nanocrystal prepared in Example 4 was dispersed in toluene at a concentration of 10 ⁇ g / mL.
  • FIG. 27 shows the UV-Vis absorption spectrum and PL spectrum of this colloidal solution.
  • MAPbI 3 perovskite nanocrystals capped with hexadecylamine and oleic acid show particularly stable photoluminescence.
  • FIG. 28 shows a PL spectrum of the colloidal solution of MAPbI 3 perovskite nanocrystals immediately after synthesis shown in FIG. 27 and a PL spectrum of the colloidal solution of MAPbI 3 perovskite nanocrystals measured after storage for 2 months from the synthesis. is there.
  • the PL spectrum intensity and profile of the MAPbI 3 perovskite nanocrystal did not substantially change even after 2 months.
  • the MAPbX 3 perovskite nanocrystals produced in Example 5 were evaluated by the same UV-Vis absorption and PL spectroscopy as described above.
  • this perovskite nanocrystal thin film can be used as a quantum dot array, has a wide range of selection of emission colors, has high brightness and high light durability, and has high efficiency. It is possible to realize a photoelectric conversion element or a photovoltaic element such as a high-performance solar cell having high durability. In addition, this perovskite nanocrystal thin film can be easily manufactured.
  • FIG. 32 shows a light emitting diode according to the second embodiment.
  • This light emitting diode uses the perovskite nanocrystal thin film according to the first embodiment as a light emitting layer.
  • the light emitting diode has a structure in which a perovskite nanocrystal thin film 100 used as a light emitting layer is sandwiched between a transparent electron injection layer 200 and a hole transport layer 300.
  • a transparent electrode 400 is provided on the electron injection layer 200.
  • An electrode 500 is provided on the hole transport layer 300.
  • the electron injection layer 200 is made of ZnO, for example.
  • the hole transport layer 300 is made of, for example, CBP / MoO 3 .
  • CBP is 4,4′-bis (N-carbazolyl) -1,1′-biphenyl (4,4′-Bis (N-carbazolyl) -1,1′-biphenyl).
  • the transparent electrode 400 is made of, for example, a glass substrate coated with indium-tin oxide (ITO).
  • An electron injection layer 200, a perovskite nanocrystal thin film 100, a hole transport layer 300, and an electrode 500 are sequentially formed on the entire surface of the transparent electrode 400, and then these are patterned by lithography and etching to manufacture the light emitting diode shown in FIG. .
  • a direct current voltage is applied between the transparent electrode 400 and the electrode 500 to cause a current to flow, thereby injecting electrons (e) from the electron injection layer 200 into the perovskite nanocrystal thin film 100 and at the same time, holes Holes (h) are injected from the transport layer 300.
  • the electrons and holes thus injected into the perovskite nanocrystal thin film 100 are recombined in the perovskite nanocrystal 20 to generate light emission, whereby the perovskite nanocrystal thin film 100 emits light and the light is extracted to the outside through the transparent electrode 400.
  • the perovskite nanocrystal thin film 100 is used as the light emitting layer, the emission color selection range is wide, and the high-performance novel light emission with high brightness and high light durability is provided.
  • a diode can be realized.

Abstract

A perovskite nano-crystal thin film comprises a plurality of perovskite nano-crystals which are bonded to each other through ligands to thereby be arranged two-dimensionally or three-dimensionally, wherein each of the perovskite nano-crystals is represented by the chemical formula: ABX3 (wherein A = CH3NH3, Cs or CH(NH2)2; B = Pb, Cd, Sb, Bi or Sn; X = Cl, Br or I). The ligands are oleic acid and Y-(CH2)n-NH2 (Y = H or NH2; n = 6, 8 to 16, 18, 20, 21 or 34). The perovskite nano-crystal thin film is formed by attaching a solution prepared by dispersing the perovskite nano-crystals having the ligands attached thereto in a solvent onto a substrate and then drying the solution, thereby self-assembling the perovskite nano-crystals having the ligands attached thereto.

Description

ペロブスカイトナノ結晶薄膜、ペロブスカイトナノ結晶薄膜の製造方法、発光素子、光電変換素子、表示装置および電子機器Perovskite nanocrystal thin film, method of manufacturing perovskite nanocrystal thin film, light emitting device, photoelectric conversion device, display device, and electronic device
　この発明は、ペロブスカイトナノ結晶薄膜、ペロブスカイトナノ結晶薄膜の製造方法、発光素子、光電変換素子、表示装置および電子機器に関し、例えば、鉛ハライドペロブスカイトナノ結晶薄膜を用いた発光ダイオード、太陽電池、光検出素子、表示装置などに適用して好適なものである。 The present invention relates to a perovskite nanocrystal thin film, a method for manufacturing a perovskite nanocrystal thin film, a light emitting element, a photoelectric conversion element, a display device, and an electronic device, for example, a light emitting diode using a lead halide perovskite nanocrystal thin film, a solar cell, and light detection. It is suitable for application to elements, display devices, and the like.
　半導体ナノテクノロジーの分野において重金属カルコゲナイドからなる量子ドットが開発されてから３０年以上経つが、近年では、量子ドットに無機あるいは無機－有機ハライドペロブスカイトを適用する研究が盛んに行われている。ペロブスカイトは、安価な前駆体から簡単に合成することができ、発光色も広範囲に及び、狭帯域のフォトルミネッセンス（ＰＬ）が得られ、光生成された荷電キャリアーの拡散長が大きいなどの優れた光学的および電気的性質を有する。このため、ペロブスカイトナノ結晶からなる量子ドットを用いた太陽電池、レーザー、発光ダイオード（ＬＥＤ）などの開発が進められている（例えば特許文献１～３参照）。 More than 30 years have passed since the quantum dots made of heavy metal chalcogenides were developed in the field of semiconductor nanotechnology, but in recent years, active research has been conducted on applying inorganic or inorganic-organic halide perovskites to quantum dots. Perovskites are excellent in that they can be easily synthesized from inexpensive precursors, have a wide range of emission colors, can obtain narrow-band photoluminescence (PL), and have a large diffusion length of photogenerated charge carriers. It has optical and electrical properties. For this reason, development of solar cells, lasers, light emitting diodes (LEDs), and the like using quantum dots made of perovskite nanocrystals is underway (see, for example, Patent Documents 1 to 3).
特開２０１７－２２２８５１号公報JP, 2017-222851, A 特表２０１７－５３６４５０号公報Japanese Patent Publication No. 2017-536450 特許第６２９７４２号明細書Patent No. 629742
　太陽電池やＬＥＤなどにペロブスカイトナノ結晶を用いた量子ドットを適用する場合、ペロブスカイトナノ結晶が配列された薄膜を用いることができれば、太陽電池やＬＥＤなどの構造および製造が簡単になると考えられ、望ましい。 When quantum dots using perovskite nanocrystals are applied to solar cells, LEDs, etc., it is thought that if a thin film in which perovskite nanocrystals are arranged can be used, the structure and manufacturing of solar cells, LEDs, etc. will be simplified, which is desirable. .
　しかしながら、本発明者らの知る限り、これまで、ペロブスカイトナノ結晶が配列された薄膜を簡単に製造する方法およびそのような薄膜の具体的構造は知られていない。 However, as far as the inventors know, a method for easily producing a thin film in which perovskite nanocrystals are arranged and a specific structure of such a thin film have not been known so far.
　そこで、この発明が解決しようとする課題は、量子ドットアレイとして用いることができる、ペロブスカイトナノ結晶が配列されたペロブスカイトナノ結晶薄膜およびそのようなペロブスカイトナノ結晶薄膜を簡単に製造することができる製造方法ならびにこのペロブスカイトナノ結晶薄膜を用いた発光素子、光電変換素子、表示装置および電子機器を提供することである。 Therefore, the problem to be solved by the present invention is to use as a quantum dot array, a perovskite nanocrystal thin film in which perovskite nanocrystals are arranged, and a manufacturing method capable of easily producing such a perovskite nanocrystal thin film. Another object of the present invention is to provide a light emitting device, a photoelectric conversion device, a display device and an electronic device using the perovskite nanocrystal thin film.
　上記課題を解決するために、この発明は、
　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜である。 In order to solve the above problems, the present invention provides
A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I) is a perovskite nanocrystal thin film composed of perovskite nanocrystals.
　ここで、ペロブスカイトナノ結晶同士を結合するリガンドは、ペロブスカイトナノ結晶間の設定距離に応じて適宜選択される。リガンドは、単座配位（monodentate)であっても二座配位（bidentate)などの多座配位であってもよい。リガンドの長さは、リガンドで結合されたペロブスカイトナノ結晶間の相互作用を得る観点より一般的には３．７ｎｍ以下に選択される。リガンドの長さの下限は特にないが、リガンドの長さは一般的には０．８７ｎｍ以上である。具体的には、リガンドとしては、例えば、オレイン酸（ＣＨ3 （ＣＨ2 ）7 ＣＨ＝ＣＨ（ＣＨ2 ）7 ＣＯＯＨ）と、Ｙ－（ＣＨ2 ）n －ＮＨ2 （ただし、Ｙ＝ＨまたはＮＨ2 、ｎ＝６，８，９，１０，１１，１２，１３，１４，１５，１６，１８，２０，２１，３４）、Ｙ－（ＣＨ2 ）n －Ｙ（ただし、Ｙ＝ＮＨ2 、ｎ＝４，５，６，７，８，９，１０，１１，１２，１３，１４，１５，１６，１８，２０，２１，３４）、Ｚ－（ＣＨ2 ）n －Ｚ（Ｚ＝ＣＯＯＨ、ｎ＝４，５，６，７，８，９，１０，１１，１２，１３，１４，１５，１６，１８，２０，２１，３４）およびオレイルアミン（Ｃ18Ｈ37Ｎ、ＣＨ3 （ＣＨ2 ）7 ＣＨ＝ＣＨ（ＣＨ2 ）8 ＮＨ2 ）からなる群から選択された少なくとも一つとが用いられる。これらのリガンドの長さは０．８７ｎｍ以上３．７ｎｍ以下の範囲内である。 Here, the ligand that binds the perovskite nanocrystals to each other is appropriately selected according to the set distance between the perovskite nanocrystals. The ligand may be monodentate or multidentate, such as bidentate. The length of the ligand is generally selected to be 3.7 nm or less from the viewpoint of obtaining the interaction between the perovskite nanocrystals bound by the ligand. The lower limit of the length of the ligand is not particularly limited, but the length of the ligand is generally 0.87 nm or more. Specifically, as the ligand, for example, oleic acid (CH 3 (CH 2 ) 7 CH═CH (CH 2 ) 7 COOH) and Y— (CH 2 ) n —NH 2 (where Y = H or NH 2, n = 6,8,9,10,11,12,13,14,15,16,18,20,21,34), Y- (CH 2) n -Y ( although, Y = NH 2 , N = 4,5,6,7,8,9,10,11,12,13,14,15,16,18,20,21,34), Z- (CH 2 ) n -Z (Z = COOH, n = 4,5,6,7,8,9,10,11,12,13,14,15,16,18,20,21,34) and oleylamine (C 18 H 37 N, CH 3 ( At least one selected from the group consisting of CH 2 ) 7 CH═CH (CH 2 ) 8 NH 2 ) is used. The length of these ligands is in the range of 0.87 nm or more and 3.7 nm or less.
　このペロブスカイトナノ結晶薄膜の用途は特に限定されず、量子ドットアレイを用いる各種の素子に用いることができるが、好適には、光照射または電流注入により発光が生じる発光層あるいは光照射により電流または電圧を取り出すことができる光電変換層として用いられる。必要に応じて、互いに同一または異なるペロブスカイトナノ結晶薄膜を複数層、積層して用いてもよい。 The application of this perovskite nanocrystal thin film is not particularly limited, and it can be used for various devices using a quantum dot array, but preferably, a light emitting layer that emits light by light irradiation or current injection, or a current or voltage by light irradiation. Used as a photoelectric conversion layer capable of taking out. If necessary, a plurality of layers of the same or different perovskite nanocrystal thin films may be laminated and used.
　特に、このペロブスカイトナノ結晶薄膜を発光層として用いる場合には、ＡＢＸ3 を構成するＡ、Ｂ、Ｘの選択およびペロブスカイトナノ結晶間の距離を決めるリガンドの選択により、発光色を制御することができる。言い換えると、ＡＢＸ3 を構成するＡ、Ｂ、Ｘおよびリガンドは発光色に応じて選択される。 In particular, when this perovskite nanocrystal thin film is used as a light emitting layer, the emission color can be controlled by selecting A, B, and X forming ABX 3 and a ligand that determines the distance between the perovskite nanocrystals. . In other words, A, B, X and the ligand that compose ABX 3 are selected according to the emission color.
　ペロブスカイトナノ結晶の大きさは必要に応じて選ばれるが、一般的には５ｎｍ以上１５ｎｍ以下、典型的には８ｎｍ以上１２ｎｍ以下である。ペロブスカイトナノ結晶間の距離（互いに隣接する二つのペロブスカイトナノ結晶間の間隙の長さ）は、一般的には２ｎｍ以上５ｎｍ以下であるが、これに限定されるものではない。ペロブスカイトナノ結晶の形状は特に限定されないが、一般的には立方体である。 The size of the perovskite nanocrystal is selected according to need, but is generally 5 nm or more and 15 nm or less, and typically 8 nm or more and 12 nm or less. The distance between the perovskite nanocrystals (the length of the gap between two adjacent perovskite nanocrystals) is generally 2 nm or more and 5 nm or less, but is not limited thereto. The shape of the perovskite nanocrystal is not particularly limited, but is generally cubic.
　また、この発明は、
　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜の製造方法であって、
　上記リガンドが結合した上記ペロブスカイトナノ結晶を溶媒に分散させた溶液を基板に付着させる工程と、
　上記基板に付着した上記溶液を乾燥させることにより上記リガンドが結合した上記ペロブスカイトナノ結晶を自己集合させて上記リガンドを介して互いに結合した上記ペロブスカイトナノ結晶からなる薄膜を形成する工程と
を有することを特徴とするペロブスカイトナノ結晶薄膜の製造方法である。 Further, the present invention is
A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I), a perovskite nanocrystal thin film comprising a perovskite nanocrystal represented by:
Attaching a solution in which the perovskite nanocrystals bound with the ligand are dispersed in a solvent to a substrate,
Drying the solution attached to the substrate to self-assemble the perovskite nanocrystals bound with the ligand to form a thin film of the perovskite nanocrystals bound to each other via the ligand. A method for producing a characteristic perovskite nanocrystal thin film.
　リガンドが結合したペロブスカイトナノ結晶を溶媒に分散させた溶液の濃度は、低すぎるとリガンドを介して互いに結合したペロブスカイトナノ結晶からなる薄膜が得られにくいため、好適には０．５ｍｇ／ｍＬより大きく選択され、一方、高すぎるとリガンドが結合したペロブスカイトナノ結晶が凝集するおそれがあるため、好適には１．５ｍｇ／ｍＬ以下に選択される。リガンドが結合したペロブスカイトナノ結晶を分散させる溶媒としては、好適には非プロトン性溶媒が用いられる。非プロトン性溶媒は、例えば、トルエン、ヘキサン、ジクロロエチレン、トリクロロエチレン、クロロホルム、クロロベンゼン、ジクロロベンゼン、スチレン、ジメチルホルムアミド、ジメチルスルホキシド、キシレン、シクロヘキセン、イソプロピルアルコールなどである。 If the concentration of the solution in which the ligand-bound perovskite nanocrystals are dispersed in the solvent is too low, it is difficult to obtain a thin film composed of perovskite nanocrystals bound to each other via the ligand. Therefore, the concentration is preferably larger than 0.5 mg / mL. On the other hand, if it is too high, ligand-bound perovskite nanocrystals may aggregate, so it is preferably selected at 1.5 mg / mL or less. An aprotic solvent is preferably used as the solvent in which the perovskite nanocrystals to which the ligand is bound are dispersed. The aprotic solvent is, for example, toluene, hexane, dichloroethylene, trichloroethylene, chloroform, chlorobenzene, dichlorobenzene, styrene, dimethylformamide, dimethylsulfoxide, xylene, cyclohexene, isopropyl alcohol and the like.
　リガンドが結合したペロブスカイトナノ結晶は種々の方法により形成することができ、その形成方法は必要に応じて選ばれる。典型的な一つの例では、ＡＸとＢＸ2 とＹ－（ＣＨ2 ）n －ＮＨ2 とオレイン酸とを溶媒に溶解して前駆体溶液を作製する工程と、この前駆体溶液からリガンドが結合したペロブスカイトナノ結晶を析出させる工程とを順次実行することにより、リガンドが結合したペロブスカイトナノ結晶を形成する。ＡＸとＢＸ2 とＹ－（ＣＨ2 ）n －ＮＨ2 とオレイン酸とを溶解する溶媒としては、例えば、Ｎ－ジメチルホルムアミド（ＤＭＦ）が用いられるが、これに限定されるものではない。一般的には、前駆体溶液を作製した後、この前駆体溶液をこの前駆体溶液の溶媒と異なる他の溶媒に混合し、そこからリガンドが結合したペロブスカイトナノ結晶を析出させる。この他の溶媒としては、好適には、上記の非プロトン性溶媒が用いられる。 The perovskite nanocrystal to which the ligand is bound can be formed by various methods, and the forming method is selected as necessary. In one typical example, AX, BX 2 , Y— (CH 2 ) n —NH 2 and oleic acid are dissolved in a solvent to prepare a precursor solution, and a ligand is bound from the precursor solution. By sequentially performing the step of depositing the perovskite nanocrystals described above, the perovskite nanocrystals to which the ligand is bound are formed. As a solvent for dissolving AX, BX 2 , Y- (CH 2 ) n- NH 2 and oleic acid, for example, N-dimethylformamide (DMF) is used, but it is not limited thereto. Generally, after the precursor solution is prepared, the precursor solution is mixed with another solvent different from the solvent of the precursor solution, and the perovskite nanocrystals to which the ligand is bound are precipitated therefrom. As the other solvent, the aprotic solvent described above is preferably used.
　このペロブスカイトナノ結晶薄膜の製造方法の発明においては、上記以外のことは、上記のペロブスカイトナノ結晶薄膜の発明に関連して説明したことが成立する。 In the invention of the method for manufacturing a perovskite nanocrystal thin film, the matters other than the above are established as explained in relation to the invention of the perovskite nanocrystal thin film.
　また、この発明は、
　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜により形成された発光層を有する発光素子である。 Further, the present invention is
A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I) is a light emitting device having a light emitting layer formed of a perovskite nanocrystal thin film composed of perovskite nanocrystals.
　発光素子は、発光ダイオードやレーザーであり、発光層（レーザーでは活性層）を構成するペロブスカイトナノ結晶薄膜の両側に電極が設けられ、これらの電極間に電流を流すことにより発光を生じさせる。 The light emitting element is a light emitting diode or a laser, and electrodes are provided on both sides of the perovskite nanocrystal thin film that constitutes the light emitting layer (active layer in laser), and light emission is caused by passing an electric current between these electrodes.
　この発光素子の発明においては、上記以外のことは、上記のペロブスカイトナノ結晶薄膜の発明に関連して説明したことが成立する。 Regarding the invention of this light-emitting element, other than the above, it is established that the explanation was made in relation to the invention of the perovskite nanocrystal thin film.
　また、この発明は、
　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜により形成された光電変換層を有する光電変換素子である。 Further, the present invention is
A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I), a photoelectric conversion element having a photoelectric conversion layer formed of a perovskite nanocrystal thin film composed of perovskite nanocrystals.
　光電変換素子は、例えば、太陽電池、光検出素子（フォトダイオードなど）などである。 The photoelectric conversion element is, for example, a solar cell, a light detection element (photodiode, etc.), or the like.
　この光電変換素子の発明においては、上記以外のことは、上記のペロブスカイトナノ結晶薄膜の発明に関連して説明したことが成立する。 Regarding the invention of this photoelectric conversion element, other than the above, the explanation is made in relation to the invention of the perovskite nanocrystal thin film.
　また、この発明は、
　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜を有する表示装置である。 Further, the present invention is
A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I) is a display device having a perovskite nanocrystal thin film composed of perovskite nanocrystals.
　表示装置は、例えば、テレビ、ＰＣ用モニター、デジタルカメラ、デジタルビデオカメラ、スマートフォンなどの電子機器あるいはその一部に用いられるものである。 The display device is used for an electronic device such as a television, a monitor for PC, a digital camera, a digital video camera, a smartphone, or a part thereof.
　この表示装置の発明においては、上記以外のことは、上記のペロブスカイトナノ結晶薄膜の発明に関連して説明したことが成立する。 In the invention of this display device, other than the above, it is established that the invention described above in connection with the invention of the perovskite nanocrystal thin film is established.
　また、この発明は、
　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜を有する電子機器である。 Further, the present invention is
A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I) is an electronic device having a perovskite nanocrystal thin film composed of perovskite nanocrystals.
　電子機器は、基本的にはどのようなものであってもよく、携帯型のものと据え置き型のものとの双方を含むが、具体例を挙げると、携帯電話、モバイル機器、ロボット、パーソナルコンピュータ、車載機器、各種家庭電気製品などである。この電子機器において、ペロブスカイトナノ結晶薄膜を光電変換層として用いる場合には、光電変換層を用いて得られた電力を電子機器に用いることができる。また、電子機器がその一部に表示装置を有する場合、この表示装置においてペロブスカイトナノ結晶薄膜を表示に用いることができる。 The electronic device may be basically any type, and includes both a portable type and a stationary type, but specific examples thereof are a mobile phone, a mobile device, a robot, and a personal computer. , In-vehicle equipment, various home appliances, etc. In this electronic device, when the perovskite nanocrystal thin film is used as the photoelectric conversion layer, the electric power obtained by using the photoelectric conversion layer can be used in the electronic device. When the electronic device has a display device as a part thereof, the perovskite nanocrystal thin film can be used for display in this display device.
　この電子機器の発明においては、上記以外のことは、上記のペロブスカイトナノ結晶薄膜の発明に関連して説明したことが成立する。 In the invention of this electronic device, other than the above, the explanations related to the invention of the perovskite nanocrystal thin film are established.
　この発明によれば、ペロブスカイトナノ結晶がリガンドを介して結合して配列した新規なペロブスカイトナノ結晶薄膜を実現することができる。このペロブスカイトナノ結晶薄膜は、ペロブスカイトナノ結晶からなる量子ドットが配列した量子ドットアレイとして用いることができる。このペロブスカイトナノ結晶薄膜を発光素子の発光層として用いることにより、発光色を容易に選択することができるだけでなく、高効率の発光および高い光耐久性を得ることができる。また、このペロブスカイトナノ結晶薄膜を光電変換素子の光電変換層として用いることにより、高効率の光電変換を行うことができるだけでなく、高い光耐久性を得ることができる。以上により、高性能の発光素子、光電変換素子、表示装置および電子機器を実現することができる。 According to the present invention, it is possible to realize a novel perovskite nanocrystal thin film in which perovskite nanocrystals are bound by ligands and arranged. This perovskite nanocrystal thin film can be used as a quantum dot array in which quantum dots made of perovskite nanocrystals are arranged. By using this perovskite nanocrystal thin film as a light emitting layer of a light emitting device, not only the emission color can be easily selected, but also highly efficient light emission and high light durability can be obtained. Further, by using this perovskite nanocrystal thin film as a photoelectric conversion layer of a photoelectric conversion element, not only highly efficient photoelectric conversion can be performed but also high light durability can be obtained. As described above, a high-performance light emitting element, photoelectric conversion element, display device, and electronic device can be realized.
この発明の第１の実施の形態によるペロブスカイトナノ結晶薄膜を示す略線図である。1 is a schematic diagram showing a perovskite nanocrystal thin film according to a first embodiment of the present invention. この発明の第１の実施の形態によるペロブスカイトナノ結晶薄膜の製造に使用されるリガンドが結合したペロブスカイトナノ結晶を示す略線図である。FIG. 3 is a schematic diagram showing a ligand-bonded perovskite nanocrystal used for manufacturing the perovskite nanocrystal thin film according to the first embodiment of the present invention. この発明の第１の実施の形態によるペロブスカイトナノ結晶薄膜の製造に使用される、リガンドが結合したペロブスカイトナノ結晶が分散された溶液を示す略線図である。FIG. 3 is a schematic diagram showing a solution in which a perovskite nanocrystal having a ligand bound thereto is dispersed, which is used for manufacturing a perovskite nanocrystal thin film according to the first embodiment of the present invention. 実施例１で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶のコロイド溶液の吸収スペクトルおよびＰＬスペクトルを示す略線図である。 3 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of MAPbBr 3 perovskite nanocrystals produced in Example 1. FIG. 実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶のコロイド溶液の吸収スペクトルおよびＰＬスペクトルを示す略線図である。3 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of FAPbBr 3 perovskite nanocrystals produced in Example 3. FIG. 実施例２で作製したＣｓＰｂＢｒ3 ペロブスカイトナノ結晶のコロイド溶液の吸収スペクトルおよびＰＬスペクトルを示す略線図である。5 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of CsPbBr 3 perovskite nanocrystals produced in Example 2. FIG. コロイド溶液中のＭＡＰｂＢｒ3 ペロブスカイトナノ結晶、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶およびＣｓＰｂＢｒ3 ペロブスカイトナノ結晶のＰＬ減衰プロファイルを示す略線図である。FIG. 3 is a schematic diagram showing PL attenuation profiles of MAPbBr 3 perovskite nanocrystals, FAPbBr 3 perovskite nanocrystals and CsPbBr 3 perovskite nanocrystals in a colloidal solution. コロイド溶液中のＭＡＰｂＢｒ3 ペロブスカイトナノ結晶、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶およびＣｓＰｂＢｒ3 ペロブスカイトナノ結晶のバンドギャップの決定方法を説明するための略線図である。MAPbBr 3 perovskite nanocrystals in the colloidal solution is a schematic diagram for explaining a method of determining the band gap of the FAPbBr 3 perovskite nanocrystals and CsPbBr 3 perovskite nanocrystals. 実施例１で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶の透過型電子顕微鏡像を示す図面代用写真である。5 is a drawing-substituting photograph showing a transmission electron microscope image of the MAPbBr 3 perovskite nanocrystals produced in Example 1. 実施例１で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶、実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶および実施例２で作製したＣｓＰｂＢｒ3 ペロブスカイトナノ結晶の粉末Ｘ線回折パターンを示す略線図である。MAPbBr 3 perovskite nanocrystals prepared in Example 1, is a schematic diagram illustrating a powder X-ray diffraction pattern of CsPbBr 3 perovskite nanocrystals prepared in FAPbBr 3 perovskite nanocrystals and Example 2 produced in Example 3. 実施例１で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の作製方法を示す略線図である。5 is a schematic diagram showing a method of manufacturing the MAPbBr 3 perovskite nanocrystal thin film manufactured in Example 1. FIG. 実施例１で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜のＵＶランプ下の写真を示す図面代用写真である。6 is a drawing-substituting photograph showing a photograph of a MAPbBr 3 perovskite nanocrystal thin film produced in Example 1, under a UV lamp. 実施例１で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜への入射光子束の強度を増加させた時の増幅放射の変化を示す図面代用写真である。7 is a drawing-substituting photograph showing a change in amplified radiation when the intensity of incident photon flux on the MAPbBr 3 perovskite nanocrystal thin film produced in Example 1 is increased. 実施例１で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時のＰＬスペクトルの変化を示す略線図である。5 is a schematic diagram showing a change in PL spectrum when the laser fluence of the MAPbBr 3 perovskite nanocrystal thin film produced in Example 1 is changed. FIG. 実施例１で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時のＰＬ減衰プロファイルの変化を示す略線図である。5 is a schematic diagram showing a change in PL attenuation profile when the laser fluence on the MAPbBr 3 perovskite nanocrystal thin film produced in Example 1 is changed. FIG. 実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の時間－スペクトル分解光子計測マップの変化を説明するための略線図である。5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed. FIG. 実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の時間－スペクトル分解光子計測マップの変化を説明するための略線図である。5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed. FIG. 実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の時間－スペクトル分解光子計測マップの変化を説明するための略線図である。5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed. FIG. 実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の時間－スペクトル分解光子計測マップの変化を説明するための略線図である。5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed. FIG. 実施例１で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の平均ＰＬ寿命および光子計測数の片対数プロットを示す略線図である。5 is a schematic diagram showing a semi-logarithmic plot of the average PL lifetime and the number of photons measured when the laser fluence of the MAPbBr 3 perovskite nanocrystal thin film produced in Example 1 was changed. 実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の平均ＰＬ寿命および光子計測数の片対数プロットを示す略線図である。6 is a schematic diagram showing a semi-logarithmic plot of the average PL lifetime and the number of photons measured when the laser fluence on the FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 was changed. 実施例２で作製したＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の平均ＰＬ寿命および光子計測数の片対数プロットを示す略線図である。5 is a schematic diagram showing a semilogarithmic plot of the average PL lifetime and the number of photons measured when the laser fluence on the CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 was changed. 低レーザーフルエンス時のペロブスカイトナノ結晶薄膜における荷電キャリアーの拡散および再結合を示す略線図である。FIG. 4 is a schematic diagram showing diffusion and recombination of charge carriers in a perovskite nanocrystal thin film at low laser fluence. 高レーザーフルエンス時のペロブスカイトナノ結晶薄膜における荷電キャリアーの拡散および再結合を示す略線図である。FIG. 6 is a schematic diagram showing diffusion and recombination of charge carriers in a perovskite nanocrystal thin film at high laser fluence. ペロブスカイトナノ結晶薄膜の照射領域をマスクしない場合に時間分解ＰＬ測定を行う方法を示す略線図である。It is an approximate line figure showing the method of performing time resolved PL measurement, when the irradiation field of a perovskite nanocrystal thin film is not masked. ペロブスカイトナノ結晶薄膜の照射領域をマスクする場合に時間分解ＰＬ測定を行う方法を示す略線図である。It is an approximate line figure showing the method of performing time resolved PL measurement, when masking the irradiation field of a perovskite nanocrystal thin film. 実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の低入射光子束下での非照射領域、低入射光子束下での中央の照射領域および高入射光子束下での中央の照射領域のＰＬ減衰プロファイルを示す略線図である。PL attenuation of the FAPbBr 3 perovskite nanocrystal thin film prepared in Example 3 in a non-irradiated region under a low incident photon flux, a central irradiated region under a low incident photon flux, and a central irradiated region under a high incident photon flux. It is an approximate line figure showing a profile. 実施例１で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の低レーザーフルエンス下で２００ｎｓ毎に取得した積分ＰＬスペクトルを示す略線図である。 3 is a schematic diagram showing an integrated PL spectrum obtained every 200 ns under a low laser fluence of the MAPbBr 3 perovskite nanocrystal thin film produced in Example 1. FIG. 実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の低レーザーフルエンス下での非照射領域および照射領域からの積分ＰＬスペクトルを示す略線図である。5 is a schematic diagram showing integrated PL spectra from a non-irradiated region and an irradiated region of a FAPbBr 3 perovskite nanocrystal thin film manufactured in Example 3 under a low laser fluence. 実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜のペロブスカイトナノ結晶の密度を変化させた時のＰＬスペクトルの変化を示す略線図である。6 is a schematic diagram showing a change in PL spectrum when the density of perovskite nanocrystals of the FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed. FIG. 実施例３で作製したＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜のペロブスカイトナノ結晶の密度を変化させた時のＰＬ減衰プロファイルの変化を示す略線図である。5 is a schematic diagram showing a change in PL attenuation profile when the density of perovskite nanocrystals of the FAPbBr 3 perovskite nanocrystal thin film produced in Example 3 is changed. FIG. 実施例２で作製したＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の時間－スペクトル分解光子計測マップの変化を説明するための略線図である。5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 is changed. FIG. 実施例２で作製したＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の時間－スペクトル分解光子計測マップの変化を説明するための略線図である。5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 is changed. FIG. 実施例２で作製したＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の時間－スペクトル分解光子計測マップの変化を説明するための略線図である。5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 is changed. FIG. 実施例２で作製したＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを変化させた時の時間－スペクトル分解光子計測マップの変化を説明するための略線図である。5 is a schematic diagram for explaining a change in a time-spectrum resolved photon measurement map when a laser fluence on a CsPbBr 3 perovskite nanocrystal thin film produced in Example 2 is changed. FIG. 実施例４で作製したＭＡＰｂＩ3 ペロブスカイトナノ結晶のコロイド溶液の吸収スペクトルおよびＰＬスペクトルを示す略線図である。7 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of MAPbI 3 perovskite nanocrystals produced in Example 4. FIG. 実施例４で作製した合成直後のＭＡＰｂＩ3 ペロブスカイトナノ結晶のコロイド溶液のＰＬスペクトルに合成から２ヶ月経過後のＭＡＰｂＩ3 ペロブスカイトナノ結晶のコロイド溶液のＰＬスペクトルを重ねて示す略線図である。FIG. 6 is a schematic diagram showing a PL spectrum of a colloidal solution of MAPbI 3 perovskite nanocrystals immediately after synthesis prepared in Example 4 and a PL spectrum of a colloidal solution of MAPbI 3 perovskite nanocrystals after 2 months from the synthesis. 実施例５で作製したＭＡＰｂＣｌ3 ペロブスカイトナノ結晶のコロイド溶液の吸収スペクトルおよびＰＬスペクトルを示す略線図である。7 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of MAPbCl 3 perovskite nanocrystals produced in Example 5. FIG. 実施例５で作製したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶のコロイド溶液の吸収スペクトルおよびＰＬスペクトルを示す略線図である。5 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of MAPbBr 3 perovskite nanocrystals produced in Example 5. FIG. 実施例５で作製したＭＡＰｂＩ3 ペロブスカイトナノ結晶のコロイド溶液の吸収スペクトルおよびＰＬスペクトルを示す略線図である。5 is a schematic diagram showing an absorption spectrum and a PL spectrum of a colloidal solution of MAPbI 3 perovskite nanocrystals produced in Example 5. FIG. この発明の第２の実施の形態による発光ダイオードを示す斜視図である。It is a perspective view which shows the light emitting diode by the 2nd Embodiment of this invention.
　以下、発明を実施するための形態（以下、「実施の形態」という。）について図面を参照しながら説明する。 Hereinafter, modes for carrying out the invention (hereinafter, referred to as “embodiments”) will be described with reference to the drawings.
〈第１の実施の形態〉
［ペロブスカイトナノ結晶薄膜］
　図１は第１の実施の形態によるペロブスカイトナノ結晶薄膜を示す。 <First Embodiment>
[Perovskite nanocrystal thin film]
FIG. 1 shows a perovskite nanocrystal thin film according to the first embodiment.
　図１に示すように、このペロブスカイトナノ結晶薄膜は、リガンド１０を介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （Ａ、Ｂ、Ｘは既に述べた通り）で表されるペロブスカイトナノ結晶２０からなる。図１では、ペロブスカイトナノ結晶２０が二次元に配列されている場合が示されている。一つのペロブスカイトナノ結晶２０は量子ドットを構成し、従ってこのペロブスカイトナノ結晶薄膜は量子ドットアレイを構成する。図１では、ペロブスカイトナノ結晶２０が立方体の形状を有する場合が示されているが、ペロブスカイトナノ結晶２０の形状は立方体以外の形状、例えば直方体、球、楕円体などであることもある。リガンド１０は、Ｙ－（ＣＨ2 ）n －ＮＨ2 １０ａ（Ｙ＝ＨまたはＮＨ2 、ｎ＝６，８，９，１０，１１，１２，１３，１４，１５，１６，１８，２０，２１，３４）およびオレイン酸１０ｂの二種類の分子からなり、これらの分子の両端がペロブスカイトナノ結晶２０に結合している。互いに隣接する二つのペロブスカイトナノ結晶２０間の距離はこのリガンド１０の長さで決まる。 As shown in FIG. 1, the perovskite nanocrystal thin film has a plurality of chemical formulas ABX 3 (A, B, and X are as described above) that are bound to each other via a ligand 10 and are arranged in a two-dimensional or three-dimensional manner. It consists of the perovskite nanocrystals 20 represented. In FIG. 1, the case where the perovskite nanocrystals 20 are two-dimensionally arranged is shown. One perovskite nanocrystal 20 constitutes a quantum dot, and thus this perovskite nanocrystal thin film constitutes a quantum dot array. Although FIG. 1 shows a case where the perovskite nanocrystal 20 has a cubic shape, the perovskite nanocrystal 20 may have a shape other than a cube, such as a rectangular parallelepiped, a sphere, or an ellipsoid. The ligand 10 is Y- (CH 2 ) n -NH 2 10a (Y = H or NH 2 , n = 6,8,9,10,11,12,13,14,15,16,18,20,21. , 34) and oleic acid 10b, both ends of which are bound to the perovskite nanocrystal 20. The distance between two adjacent perovskite nanocrystals 20 is determined by the length of the ligand 10.
　ペロブスカイトナノ結晶２０の大きさ（一辺の長さ）は、一般には５ｎｍ以上１５ｎｍ以下であり、典型的には８ｎｍ以上１２ｎｍ以下である。ペロブスカイトナノ結晶２０間の距離は一般的には２ｎｍ以上５ｎｍ以下である。 The size (length of one side) of the perovskite nanocrystal 20 is generally 5 nm or more and 15 nm or less, and typically 8 nm or more and 12 nm or less. The distance between the perovskite nanocrystals 20 is generally 2 nm or more and 5 nm or less.
　このペロブスカイトナノ結晶薄膜は、光照射などを行うことによりフォトルミネッセンス（ＰＬ）を生じさせることができ、発光層として用いることができる。このペロブスカイトナノ結晶薄膜の発光色は、ペロブスカイトナノ結晶２０を構成するＡＢＸ3 におけるＡ、Ｂ、Ｘ、ペロブスカイトナノ結晶２０の大きさ、リガンド１０として用いる分子などの選択により選択することができる。この発光色の選択方法についてより具体的に説明する。ＡＢＸ3 は、具体的には、例えば、ＸとしてＣｌ、Ｂｒを考えるとＡＢＣｌ3-n Ｂｒn 、ＸとしてＢｒ、Ｉを考えるとＡＢＢｒ3-n Ｉn である。ペロブスカイトナノ結晶２０を１０ｎｍ×１０ｎｍ×１０ｎｍの立方体の形状とすると、ＡＢＣｌ3-n Ｂｒn の場合、発光色は、ｎ＝０では紫、ｎ＝１では青、ｎ＝２では青緑、ｎ＝３では緑である。同じく、ＡＢＢｒ3-n Ｉn の場合、発光色は、ｎ＝０では緑、ｎ＝１では黄色、ｎ＝２では橙、ｎ＝３では赤である。 This perovskite nanocrystal thin film can generate photoluminescence (PL) by performing light irradiation and can be used as a light emitting layer. The emission color of this perovskite nanocrystal thin film can be selected by selecting A, B, X in ABX 3 constituting the perovskite nanocrystal 20, the size of the perovskite nanocrystal 20, the molecule used as the ligand 10, and the like. The method of selecting the emission color will be described more specifically. ABX 3, specifically, for example, Cl as X, given the Br ABCl 3-n Br n, consider Br, an I as X when ABBr 3-n I n. Assuming that the perovskite nanocrystal 20 has a cubic shape of 10 nm × 10 nm × 10 nm, in the case of ABCl 3−n Br n , the emission color is purple at n = 0, blue at n = 1, blue green at n = 2, n = 3 is green. Similarly, if the ABBr 3-n I n, emission color, the n = 0 green, the n = 1 Yellow, n = 2 in orange, which is n = 3 in red.
　特に、Ａ＝ＣＨ3 ＮＨ3 ，ＣＨ（ＮＨ2 ）2 ，Ｃｓ、Ｂ＝Ｐｂ、リガンド１０が上述のようにＹ－（ＣＨ2 ）n －ＮＨ2 １０ａ（Ｙ＝ＨまたはＮＨ2 、ｎ＝１２，１６，１８）およびオレイン酸１０ｂからなる場合における発光色を示すと下記の通りである。 In particular, A = CH 3 NH 3 , CH (NH 2 ) 2 , Cs, B = Pb, and the ligand 10 is Y- (CH 2 ) n -NH 2 10a (Y = H or NH 2 , n = 12, 16, 18) and the luminescent color of oleic acid 10b are as follows.
　　　　ＡＢＸ3 　　　　　　発光色
　　　ＡＰｂＣｌ3 　　　　　　青
　　　ＡＰｂＢｒ3 　　　　　　緑
　　　ＡＰｂＩ3 　　　　　　　赤
　　　ＡＰｂＣｌ2 Ｂｒ　　　　青みがかったシアニン（Bluish-Cyanine)
　　　ＡＰｂＣｌＢｒ2 　　　　緑がかったシアニン（Greenish-Cyanine)
　　　ＡＰｂＢｒ2 Ｉ　　　　　黄色っぽいオレンジ（Yellowish-Orange)
　　　ＡＰｂＢｒＩ2 　　　　　オレンジ－赤（Orange-Red) ABX 3 emission color APbCl 3 blue APbBr 3 green APbI 3 red APbCl 2 Br bluish cyanine (Bluish-Cyanine)
APbClBr 2 Greenish-Cyanine
APbBr 2 I Yellowish Orange (Yellowish-Orange)
APbBrI 2 Orange-Red
［ペロブスカイトナノ結晶薄膜の製造方法］
　まず、図２に示すように、リガンド１０（Ｙ－（ＣＨ2 ）n －ＮＨ2 １０ａおよびオレイン酸１０ｂ）が結合したペロブスカイトナノ結晶２０を作製する。作製には、析出法、ホットインジェクション法などを用いることができる。具体的には、例えば、析出法では、ペロブスカイトナノ結晶の原料として例えばＡＸおよびＢＸ2 を用いる。そして、ＡＸ、ＢＸ2 、Ｙ－（ＣＨ2 ）n －ＮＨ2 およびオレイン酸をＤＭＦなどの溶媒に溶解し、攪拌などを行って前駆体溶液を作製する。こうして作製した前駆体溶液を無水トルエンなどの他の溶媒に混合し、攪拌などを行ってペロブスカイトナノ結晶２０を析出させる。この時点でペロブスカイトナノ結晶２０にリガンド１０が結合している。こうして析出したリガンド１０が結合したペロブスカイトナノ結晶２０を洗浄し、未結合のリガンド１０を除去する。 [Method for producing perovskite nanocrystalline thin film]
First, as shown in FIG. 2, a perovskite nanocrystal 20 to which a ligand 10 (Y— (CH 2 ) n —NH 2 10a and oleic acid 10b) is bound is prepared. A precipitation method, a hot injection method, or the like can be used for the production. Specifically, for example, in the precipitation method, for example, AX and BX 2 are used as a raw material of perovskite nanocrystals. Then, AX, BX 2 , Y— (CH 2 ) n —NH 2 and oleic acid are dissolved in a solvent such as DMF and stirred to prepare a precursor solution. The precursor solution thus prepared is mixed with another solvent such as anhydrous toluene and stirred to precipitate the perovskite nanocrystals 20. At this point, the ligand 10 is bound to the perovskite nanocrystal 20. The perovskite nanocrystals 20 bound with the thus-deposited ligand 10 are washed to remove the unbound ligand 10.
　次に、リガンド１０が結合したペロブスカイトナノ結晶２０をトルエンなどの溶媒に分散させ、この分散液を基板上に付着させ、乾燥させる。図３にこの分散液を模式的に示す（溶媒は図示せず）。乾燥中に分散液中のペロブスカイトナノ結晶２０が自己集合により配列し、図１に示すようにペロブスカイトナノ結晶薄膜が得られる。このとき、リガンド１０の長さにより、ペロブスカイトナノ結晶２０間の距離が決まる。リガンド１０が結合したペロブスカイトナノ結晶２０の自己集合によるペロブスカイトナノ結晶薄膜の形成は、リガンド１０間の疎水性相互作用により促進される。 Next, the perovskite nanocrystals 20 to which the ligand 10 is bound are dispersed in a solvent such as toluene, and this dispersion is attached onto a substrate and dried. This dispersion is schematically shown in FIG. 3 (solvent is not shown). During drying, the perovskite nanocrystals 20 in the dispersion are arranged by self-assembly, and a perovskite nanocrystal thin film is obtained as shown in FIG. At this time, the length of the ligand 10 determines the distance between the perovskite nanocrystals 20. The formation of the perovskite nanocrystal thin film by self-assembly of the perovskite nanocrystals 20 to which the ligands 10 are bound is promoted by the hydrophobic interaction between the ligands 10.
　一例として、ペロブスカイトナノ結晶２０を１０ｎｍ×１０ｎｍ×１０ｎｍの立方体の形状とする場合、緑色発光を得る時には、ペロブスカイトナノ結晶２０をＡＢＢｒ3 で構成すればよく、その原料としてはＡＢｒ＋ＢＢｒ2 を用いることができる。また、赤色発光を得る時には、ペロブスカイトナノ結晶２０をＡＢＩ3 で構成すればよく、その原料としてはＡＩ＋ＢＩ2 を用いることができる。また、紫色発光を得る時には、ペロブスカイトナノ結晶２０をＡＢＣｌ3 で構成すればよく、その原料としてはＡＣｌ＋ＢＣｌ2 を用いることができる。 As an example, when the perovskite nanocrystal 20 has a cubic shape of 10 nm × 10 nm × 10 nm, when green light emission is obtained, the perovskite nanocrystal 20 may be made of ABBr 3 , and ABr + BBr 2 is used as a raw material thereof. it can. Further, when red light emission is obtained, the perovskite nanocrystal 20 may be made of ABI 3 , and AI + BI 2 can be used as a raw material thereof. Further, when violet emission is obtained, the perovskite nanocrystal 20 may be made of ABCl 3 , and ACl + BCl 2 can be used as a raw material thereof.
　実施例を説明する。
（実施例１）
　ＭＡＰｂＢｒ3 （Methylammonium Lead Bromide,ＣＨ3 ＮＨ3 ＰｂＢｒ3 ）ペロブスカイトナノ結晶薄膜を以下のようにして作製した。 An example will be described.
(Example 1)
A MAPbBr 3 (Methylammonium Lead Bromide, CH 3 NH 3 PbBr 3 ) perovskite nanocrystal thin film was prepared as follows.
　まず、ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶を析出法により合成した。ＣＨ3 ＮＨ3 Ｂｒ（２８ｍｇ，０．２５ｍｍｏｌ）、ＰｂＢｒ2 （１００ｍｇ，０．２７ｍｍｏｌ）、オレイン酸（８０μＬ，０．２５ｍｍｏｌ）およびヘキサデシルアミン（４６ｍｇ，０．１９ｍｍｏｌ）を１ｍＬのＤＭＦ溶媒に投入し、６０℃に設定された水浴上で透明な前駆体溶液が形成されるまで交互に攪拌および加熱を繰り返すことにより溶解させた。こうして得られた透明な前駆体溶液を５０ｍＬの無水トルエンに注入し、激しく攪拌した。溶液はまず無色から緑色に変化し、混合により次第に濁り、オレンジ－黄色を呈したが、これはＭＡＰｂＢｒ3 ペロブスカイトナノ結晶が析出したことを示す。１５分間激しく攪拌した後、得られた生成物を１００００ｒｐｍで５分間遠心分離を行い、透明な上清を捨てた。析出物をｎ－ブタノールで洗浄して未結合の過剰なリガンドを除去した。最終的な析出物を超音波によりトルエン中に再度分散させ、５０００ｒｐｍで５分間遠心分離を行って大きい粒子を分離した。 First, MAPbBr 3 perovskite nanocrystals were synthesized by a precipitation method. CH 3 NH 3 Br (28 mg, 0.25 mmol), PbBr 2 (100 mg, 0.25 mmol), oleic acid (80 μL, 0.25 mmol) and hexadecylamine (46 mg, 0.19 mmol) were added to 1 mL of DMF solvent. Then, the solution was dissolved by repeating stirring and heating alternately until a transparent precursor solution was formed on a water bath set at 60 ° C. The transparent precursor solution thus obtained was poured into 50 mL of anhydrous toluene and vigorously stirred. The solution first changed from colorless to green, gradually became cloudy with mixing, and exhibited an orange-yellow color, indicating that MAPbBr 3 perovskite nanocrystals were precipitated. After stirring vigorously for 15 minutes, the resulting product was centrifuged at 10,000 rpm for 5 minutes and the clear supernatant was discarded. The precipitate was washed with n-butanol to remove excess unbound ligand. The final precipitate was ultrasonically dispersed again in toluene and centrifuged at 5000 rpm for 5 minutes to separate large particles.
　上述のようにして合成されたＭＡＰｂＢｒ3 ペロブスカイトナノ結晶を用いて薄膜をガラス基板上に形成するために室温滴下成形技術を用いた。すなわち、合成されたＭＡＰｂＢｒ3 ペロブスカイトナノ結晶をトルエン中に分散させてペロブスカイトナノ結晶の濃縮コロイド溶液（１ｍｇ／ｍＬ）を調製し、大気中で、サイズが２４×５０ｍｍ2 のスライドガラス上に形成された正方形のシリコーンゴムの中心に形成された円形の穴の中にこの濃縮コロイド溶液を５０μＬ注入し、乾燥させることによりＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜を形成した。 A room temperature drop molding technique was used to form a thin film on a glass substrate using the MAPbBr 3 perovskite nanocrystals synthesized as described above. That is, the synthesized MAPbBr 3 perovskite nanocrystals were dispersed in toluene to prepare a concentrated colloidal solution of perovskite nanocrystals (1 mg / mL), which was formed on a slide glass of size 24 × 50 mm 2 in the atmosphere. 50 μL of this concentrated colloidal solution was injected into the circular hole formed in the center of the square silicone rubber, and dried to form a MAPbBr 3 perovskite nanocrystal thin film.
（実施例２）
　ＣｓＰｂＢｒ3 （Cesium Lead Bromide)ペロブスカイトナノ結晶薄膜を以下のようにして作製した。 (Example 2)
A CsPbBr 3 (Cesium Lead Bromide) perovskite nanocrystal thin film was prepared as follows.
　まず、ＣｓＰｂＢｒ3 ペロブスカイトナノ結晶をホットインジェクション法により合成した。ＰｂＢｒ2 （６９０ｍｇ，１．８８ｍｍｏｌ）、オレイン酸（４ｍＬ）、ヘキサデシルアミン（３．６７０ｇ）および１－ヘキサデセン（９０ｍＬ）を５００ｍＬの２首フラスコに投入し、真空中において１２０℃で１時間乾燥した。並行して、１－ヘキサデセン（１０ｍＬ）中の酢酸セシウム（９６ｍｇ，０．５ｍｍｏｌ）も真空中において１２０℃で乾燥させた。セシウム塩を完全に溶解させるために、上記溶液に１ｍＬのオレイン酸を添加した。乾燥中に２０分毎に真空中において繰り返しアルゴンを放電させた。鉛塩の完全な溶解後に、アルゴン雰囲気で温度を１７０℃に上昇させた。この高温溶液に乾燥させた酢酸セシウム溶液をアルゴン下で注入した。５秒後、反応混合物を氷－水浴中に置くことにより反応を急停止させた。反応混合物を６０００ｒｐｍで２５分間遠心分離し、黄色の上清を捨てた。析出物を収集し、ヘキサンおよびｎ－ブタノールで洗浄した。 First, CsPbBr 3 perovskite nanocrystals were synthesized by the hot injection method. PbBr 2 (690 mg, 1.88 mmol), oleic acid (4 mL), hexadecylamine (3.670 g) and 1-hexadecene (90 mL) were placed in a 500 mL two-necked flask and dried in vacuum at 120 ° C. for 1 hour. did. In parallel, cesium acetate (96 mg, 0.5 mmol) in 1-hexadecene (10 mL) was also dried at 120 ° C. in vacuum. To the above solution was added 1 mL of oleic acid to completely dissolve the cesium salt. The argon was repeatedly discharged in vacuum every 20 minutes during drying. After complete dissolution of the lead salt, the temperature was raised to 170 ° C. in an argon atmosphere. A dry cesium acetate solution was injected into the hot solution under argon. After 5 seconds, the reaction was quenched by placing the reaction mixture in an ice-water bath. The reaction mixture was centrifuged at 6000 rpm for 25 minutes and the yellow supernatant was discarded. The precipitate was collected and washed with hexane and n-butanol.
　次に、上述のようにして合成されたＣｓＰｂＢｒ3 ペロブスカイトナノ結晶を用いて実施例１と同様にしてＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜を作製した。 Next, using the CsPbBr 3 perovskite nanocrystals synthesized as described above, a CsPbBr 3 perovskite nanocrystal thin film was prepared in the same manner as in Example 1.
（実施例３）
　ＦＡＰｂＢｒ3 （Formamidinium Lead Bromide, ＣＨ2 Ｎ2 Ｈ4 ＰｂＢｒ3)ペロブスカイトナノ結晶薄膜を以下のようにして作製した。 (Example 3)
FAPbBr 3 (Formamidinium Lead Bromide, CH 2 N 2 H 4 PbBr 3) and the perovskite nano crystal thin film was prepared in the following manner.
　まず、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶を非特許文献１に記載した方法によって合成した。すなわち、前駆体、つまり臭化ホルムアミジニウム（０．２０ｍｍｏｌ）および臭化鉛（ＩＩ）（０．１２ｍｍｏｌ）を別々に乾燥ＤＭＦ中に溶解した。これらの溶液をそれぞれ前駆体溶液Ａおよび前駆体溶液Ｂと呼ぶ。同様に、リガンドとして臭化オクチルアンモニウム（０．１２ｍｍｏｌ）およびオレイン酸（０．６ｍｍｏｌ）を連続的に攪拌を行いながら８０℃でオクタデセン（リガンド溶液）中に溶解した。前駆体溶液ＡおよびＢをこれらのリガンド溶液に添加した。このリガンドと前駆体との混合物に乾燥アセトンを添加することによってＦＡＰｂＢｒ3 ペロブスカイトナノ結晶が析出した。この混合物を７０００ｒｐｍで１０分間遠心分離し、上清を捨てた。 First, FAPbBr 3 perovskite nanocrystals were synthesized by the method described in Non-Patent Document 1. That is, the precursors, formamidinium bromide (0.20 mmol) and lead (II) bromide (0.12 mmol), were separately dissolved in dry DMF. These solutions are called precursor solution A and precursor solution B, respectively. Similarly, octyl ammonium bromide (0.12 mmol) and oleic acid (0.6 mmol) as ligands were dissolved in octadecene (ligand solution) at 80 ° C. with continuous stirring. Precursor solutions A and B were added to these ligand solutions. FAPbBr 3 perovskite nanocrystals were precipitated by adding dry acetone to the mixture of the ligand and the precursor. The mixture was centrifuged at 7000 rpm for 10 minutes and the supernatant was discarded.
　次に、上述のようにして合成されたＦＡＰｂＢｒ3 ペロブスカイトナノ結晶を用いて実施例１と同様にしてＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜を作製した。 Next, using the FAPbBr 3 perovskite nanocrystals synthesized as described above, a FAPbBr 3 perovskite nanocrystal thin film was prepared in the same manner as in Example 1.
（実施例４）
　ＭＡＰｂＩ3 （Methylammonium Lead Iodide, ＣＨ3 ＮＨ3 ＰｂＩ3 ）ペロブスカイトナノ結晶薄膜を以下のようにして作製した。 (Example 4)
A MAPbI 3 (Methylammonium Lead Iodide, CH 3 NH 3 PbI 3 ) perovskite nanocrystal thin film was prepared as follows.
　ＭＡＩ（Methylammonium Iodide)とＰｂＩ2 とをγ－ブチロラクトン（ＧＢＬ）中で混合して前駆体溶液を作製した。これとは別に、ヘキサデシルアミンとオレイン酸とをトルエンに溶解し、連続的に攪拌を行いながら８０℃に保持し、単座配位リガンド溶液を作製した。使用した前駆体、リガンドおよび溶媒の量は下記の通りである。 MAI (Methylammonium Iodide) and PbI 2 were mixed in γ-butyrolactone (GBL) to prepare a precursor solution. Separately, hexadecylamine and oleic acid were dissolved in toluene and kept at 80 ° C. with continuous stirring to prepare a monodentate ligand solution. The amounts of precursor, ligand and solvent used are as follows.
　化合物　　　　　　　　モル（ｍｍｏｌ）　重量（ｍｇ）　体積（ｍＬ）
　ＭＡＩ　　　　　　　　０．７２　　　　　１１４
　ＰｂＩ2 　　　　　　　０．７２　　　　　３４６
　オレイン酸　　　　　　３．６　　　　　　　　　　　　　１．２
　ヘキサデシルアミン　　０．７２　　　　　１７４
　ＧＢＬ　　　　　　　　　　　　　　　　　　　　　　　　１
　トルエン　　　　　　　　　　　　　　　　　　　　　　　２５ Compound mol (mmol) weight (mg) volume (mL)
MAI 0.72 114
PbI 2 0.72 346
Oleic acid 3.6 1.2
Hexadecylamine 0.72 174
GBL 1
Toluene 25
　こうして得られた前駆体溶液をリガンド溶液に迅速に注入し、連続的に攪拌を行いながら８０℃で１５分間保持して反応を行わせた。溶液は前駆体添加後に濃褐色（dark brown) に変化し、これはＭＡＰｂＩ3 ペロブスカイトナノ結晶が析出したことを示す。この混合物を７０００ｒｐｍで３分間遠心分離し、残留物および上清を収集し評価を行った。 The precursor solution thus obtained was rapidly injected into the ligand solution, and the mixture was kept at 80 ° C. for 15 minutes with continuous stirring to carry out the reaction. The solution turned dark brown after the precursor addition, indicating that MAPbI 3 perovskite nanocrystals had precipitated. This mixture was centrifuged at 7000 rpm for 3 minutes, and the residue and supernatant were collected and evaluated.
　次に、上述のようにして合成されたＭＡＰｂＩ3 ペロブスカイトナノ結晶をトルエン中に分散させてＭＡＰｂＩ3 ペロブスカイトナノ結晶のコロイド溶液を調製した。このコロイド溶液をスライドガラス上に５００ｒｐｍでスピンコーティングした後、乾燥させることによりＭＡＰｂＩ3 ペロブスカイトナノ結晶薄膜を作製した。 Next, the MAPbI 3 perovskite nanocrystals synthesized as described above were dispersed in toluene to prepare a colloidal solution of MAPbI 3 perovskite nanocrystals. This colloidal solution was spin-coated on a slide glass at 500 rpm and then dried to prepare a MAPbI 3 perovskite nanocrystal thin film.
（実施例５）
　ＭＡＰｂＸ3 （Ｘ＝Ｃｌ，Ｂｒ，Ｉ）ペロブスカイトナノ結晶薄膜を以下のようにして作製した。 (Example 5)
A MAPbX 3 (X = Cl, Br, I) perovskite nanocrystal thin film was prepared as follows.
　Ｘ＝Ｂｒ，Ｉに対しては、ＭＡＸとＰｂＸ2 とを５００μＬのＤＭＦ中で混合して透明な前駆体溶液を作製した。Ｘ＝Ｃｌに対しては、ＭＡＸとＰｂＸ2 とを２５０μＬのＤＭＦと２５０μＬのジメチルスルホキシド（ＤＭＳＯ）との混合溶媒中で混合して透明な前駆体溶液を作製した。これとは別に、１，１２－ドデカン二酸（1,12-dodecanedioc acid）と１，１２－ジアミノドデカン（1,12-diaminododecane）とをそれぞれ５００μＬのＤＭＦに溶解することにより二座配位リガンド溶液を作製した。使用した前駆体、リガンドおよび溶媒の量は下記の通りである。 For X = Br, I, MAX and PbX 2 were mixed in 500 μL DMF to make a transparent precursor solution. For X = Cl, MAX and PbX 2 were mixed in a mixed solvent of 250 μL DMF and 250 μL dimethylsulfoxide (DMSO) to prepare a transparent precursor solution. Separately, 1,12-dodecanedioic acid and 1,12-diaminododecane were dissolved in 500 μL of DMF to prepare a bidentate ligand. A solution was made. The amounts of precursor, ligand and solvent used are as follows.
　化合物　　　　　　　　　　　　　モル（ｍｍｏｌ）　重量（ｍｇ）
　ＭＡＣｌ　　　　　　　　　　　　０．３　　　　　　２０
　ＰｂＣｌ2 　　　　　　　　　　　０．２　　　　　　５６
　ＭＡＢｒ　　　　　　　　　　　　０．３　　　　　　３４
　ＰｂＢｒ2 　　　　　　　　　　　０．２　　　　　　７２
　ＭＡＩ　　　　　　　　　　　　　０．３　　　　　　４８
　ＰｂＩ2 　　　　　　　　　　　　０．２　　　　　　９２
　１，１２－ドデカン二酸　　　　　０．２　　　　　　４６
　１，１２－ジアミノドデカン　　　０．２　　　　　　４０ Compound mol (mmol) Weight (mg)
MACl 0.3 20
PbCl 2 0.2 56
MABr 0.3 34
PbBr 2 0.2 72
MAI 0.3 48
PbI 2 0.2 92
1,12-dodecanedioic acid 0.2 46
1,12-diaminododecane 0.2 40
　次に、２００μＬの１，１２－ドデカン二酸と２００μＬの前駆体溶液とを混合した。Ｘ＝Ｃｌ，Ｂｒに対しては、この混合溶液２００μＬと２００μＬの１，１２－ジアミノドデカンとを２５℃で攪拌を行いながら５０ｍＬのトルエンに注入し、反応を行わせた。Ｘ＝Ｉに対しては、この混合溶液２００μＬと２００μＬの１，１２－ジアミノドデカンとを６０℃で攪拌を行いながら５０ｍＬのトルエンに注入し、反応を行わせた。１０分間継続して反応を行わせた後、全ての試料を７０００ｒｐｍで５分間遠心分離し、残留物を収集し評価を行った。 Next, 200 μL of 1,12-dodecanedioic acid and 200 μL of the precursor solution were mixed. For X = Cl, Br, 200 μL of this mixed solution and 200 μL of 1,12-diaminododecane were poured into 50 mL of toluene while stirring at 25 ° C. to carry out a reaction. For X = I, 200 μL of this mixed solution and 200 μL of 1,12-diaminododecane were poured into 50 mL of toluene while stirring at 60 ° C. to carry out the reaction. After allowing the reaction to continue for 10 minutes, all samples were centrifuged at 7000 rpm for 5 minutes and the residue was collected and evaluated.
　次に、上述のようにして合成されたＭＡＰｂＸ3 ペロブスカイトナノ結晶を用いて実施例４と同様にしてＭＡＰｂＸ3 ペロブスカイトナノ結晶薄膜を作製した。 Next, using the MAPbX 3 perovskite nanocrystals synthesized as described above, a MAPbX 3 perovskite nanocrystal thin film was prepared in the same manner as in Example 4.
（ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶、ＣｓＰｂＢｒ3 ペロブスカイトナノ結晶、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶、ＭＡＰｂＩ3 ペロブスカイトナノ結晶およびＭＡＰｂＣｌ3 ペロブスカイトナノ結晶の評価） (Evaluation of MAPbBr 3 Perovskite Nanocrystal, CsPbBr 3 Perovskite Nanocrystal, FAPbBr 3 Perovskite Nanocrystal, MAPbI 3 Perovskite Nanocrystal, and MAPbCl 3 Perovskite Nanocrystal)
　紫外－可視（ＵＶ－Ｖｉｓ）吸収およびＰＬ分光、透過型電子顕微鏡、粉末Ｘ線回折ならびに時間分解ＰＬ測定により、上述のようにして合成されたＭＡＰｂＢｒ3 ペロブスカイトナノ結晶、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶およびＣｓＰｂＢｒ3 ペロブスカイトナノ結晶の評価を行った。 MAPbBr 3 perovskite nanocrystals, FAPbBr 3 perovskite nanocrystals and CsPbBr synthesized as described above by ultraviolet-visible (UV-Vis) absorption and PL spectroscopy, transmission electron microscopy, powder X-ray diffraction and time-resolved PL measurement. We evaluated 3 perovskite nanocrystals.
　ＵＶ－Ｖｉｓ吸収スペクトルは、合成されたペロブスカイトナノ結晶をトルエン中に分散させたコロイド溶液を用い、サーモフィッシャーサイエンティフィック（Thermo Fischer Scientific)を用いて記録した。ＰＬ分光スペクトルは、同様なコロイド溶液を用い、株式会社日立製作所製蛍光分光計（ＦＬ４１００）を用いて記録した。ＰＬ分光スペクトルの測定中、コロイド溶液を波長３６５ｎｍの光で励起した。透過型電子顕微鏡としては、加速電圧２００ｋＶの株式会社日立製作所製ＨＤ－２０００透過型電子顕微鏡を使用した。観察用の試料は、合成されたペロブスカイトナノ結晶をトルエン中に分散させ、５０００ｒｐｍで５分間遠心分離することにより大きな粒子を除去し、上清をＳＴＥＭ　Ｃｕ１００Ｐグリッド上に滴下成形し、その後真空中で乾燥させることにより作製した。粉末Ｘ線回折測定は、理学電機工業株式会社製のＣｕＫα1 励起線（λ＝１．５４０６Å）を用いたＲＩＮＴ２２００Ｘ線回折装置を用いて行った。粉末試料はペロブスカイトナノ結晶の析出物を乳鉢ですりつぶすことにより作製した。時間分解ＰＬ測定に使用した励起源は、光パラメトリック増幅器（CoherentＯＰＡ９４００）のＳＨＧ結晶から発生した４００ｎｍ（１５０ｆｓ）パルスを用いた。ＯＰＡは、モードロックＴｉ：サファイアレーザー（Coherent Mira ９００Ｆ）をシードレーザとする再生増幅器（Coherent RegA ９０００）により２００ｋＨｚでポンピングされた。ここでは、蛍光寿命システムは、ポリクロメーター（Chromex,model250IS) および光子計測ストリークカメラ（浜松ホトニクス、モデルＣ４３３４）を組み合わせたものである。試料からの蛍光信号は、４４０ｎｍのローパスフィルターを通し、ポリクロメーターの入口スリットに収束させ、ストリークカメラを用いて検出した。レーザーパワーは異なる透過率を有するニュートラルフィルターを用いて変調された。 UV-Vis absorption spectra were recorded using Thermo Fischer Scientific using a colloidal solution in which the synthesized perovskite nanocrystals were dispersed in toluene. The PL spectrum was recorded using a fluorescence spectrometer (FL4100) manufactured by Hitachi, Ltd. using the same colloidal solution. During the measurement of the PL spectrum, the colloidal solution was excited with light having a wavelength of 365 nm. As the transmission electron microscope, HD-2000 transmission electron microscope manufactured by Hitachi, Ltd. with an acceleration voltage of 200 kV was used. The sample for observation was prepared by dispersing the synthesized perovskite nanocrystals in toluene, centrifuging at 5000 rpm for 5 minutes to remove large particles, and dropping the supernatant onto a STEM Cu100P grid, followed by vacuum molding. It was made by drying. The powder X-ray diffraction measurement was carried out using a RINT2200 X-ray diffractometer using CuKα 1 excitation rays (λ = 1.5406Å) manufactured by Rigaku Denki Kogyo Co., Ltd. The powder sample was prepared by grinding the precipitate of perovskite nanocrystals in a mortar. The excitation source used for the time-resolved PL measurement was a 400 nm (150 fs) pulse generated from an SHG crystal of an optical parametric amplifier (Coherent OPA9400). The OPA was pumped at 200 kHz by a regenerative amplifier (Coherent RegA 9000) using a mode-locked Ti: sapphire laser (Coherent Mira 900F) as a seed laser. Here, the fluorescence lifetime system is a combination of a polychromator (Chromex, model250IS) and a photon measuring streak camera (Hamamatsu Photonics, model C4334). The fluorescence signal from the sample was passed through a 440 nm low-pass filter, focused on the entrance slit of the polychromator, and detected using a streak camera. The laser power was modulated using neutral filters with different transmissions.
　図４、図５および図６は、それぞれ、実施例１で作製されたＭＡＰｂＢｒ3 ペロブスカイトナノ結晶、実施例３で作製されたＦＡＰｂＢｒ3 ペロブスカイトナノ結晶および実施例２で作製されたＣｓＰｂＢｒ3 ペロブスカイトナノ結晶をトルエンに分散させたコロイド溶液のＵＶ－Ｖｉｓ吸収スペクトルおよびＰＬスペクトルを示す。図７はこれらのコロイド溶液のＰＬ減衰プロファイルを示す。 4, 5 and 6, respectively, in Example MAPbBr 3 perovskite nanocrystals made with 1, FAPbBr 3 perovskite nano prepared in Example 3 crystal and Example CsPbBr 3 perovskite nanocrystals made with 2 3 shows a UV-Vis absorption spectrum and a PL spectrum of a colloidal solution in which is dispersed in toluene. FIG. 7 shows the PL decay profiles of these colloidal solutions.
　これらのコロイド溶液中のＭＡＰｂＢｒ3 ペロブスカイトナノ結晶、ＣｓＰｂＢｒ3 ペロブスカイトナノ結晶およびＦＡＰｂＢｒ3 ペロブスカイトナノ結晶のバンドギャップをこれらのＭＡＰｂＢｒ3 ペロブスカイトナノ結晶、ＣｓＰｂＢｒ3 ペロブスカイトナノ結晶およびＦＡＰｂＢｒ3 ペロブスカイトナノ結晶のＴａｕｃプロットを行うことにより決定した。すなわち、バンドギャップは、図８に示すように、シャープなエッジにおけるＴａｕｃプロットの外挿により得られた交差点に対応するｘ軸上のエネルギー値により与えられる。ここで、Ｔａｕｃプロットは、ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶、ＣｓＰｂＢｒ3 ペロブスカイトナノ結晶およびＦＡＰｂＢｒ3 ペロブスカイトナノ結晶の吸収スペクトルから導かれる。得られたバンドギャップは、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶、ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶およびＣｓＰｂＢｒ3 ペロブスカイトナノ結晶に対してそれぞれ、２．１８ｅＶ、２．２２ｅＶおよび２．３６ｅＶであった。 MAPbBr 3 perovskite nanocrystals of these colloidal solution, CsPbBr 3 perovskite nanocrystals and FAPbBr 3 perovskite nano these MAPbBr 3 perovskite nanocrystals a band gap of the crystal, the Tauc plot of CsPbBr 3 perovskite nanocrystals and FAPbBr 3 perovskite nanocrystals It was decided by carrying out. That is, the bandgap is given by the energy value on the x-axis corresponding to the intersection obtained by extrapolation of the Tauc plot at the sharp edge, as shown in FIG. Here, Tauc plot, MAPbBr 3 perovskite nanocrystals, derived from the absorption spectra of CsPbBr 3 perovskite nanocrystals and FAPbBr 3 perovskite nanocrystals. The resulting band gap, FAPbBr 3 perovskite nanocrystals, MAPbBr 3 respectively perovskite nanocrystals and CsPbBr 3 perovskite nanocrystals, 2.18eV, was 2.22eV and 2.36 eV.
　図９はＭＡＰｂＢｒ3 ペロブスカイトナノ結晶の透過型電子顕微鏡像を示す。図９より、明らかに均一な大きさ（約１０ｎｍ）の分布を示す立方体のナノ結晶が観察される。 FIG. 9 shows a transmission electron microscope image of MAPbBr 3 perovskite nanocrystals. From FIG. 9, cubic nanocrystals having a clearly uniform size distribution (about 10 nm) are observed.
　図１０は粉末Ｘ線回折パターンを示す。この粉末Ｘ線回折パターンより、合成されたＭＡＰｂＢｒ3 ペロブスカイトナノ結晶、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶およびＣｓＰｂＢｒ3 ペロブスカイトナノ結晶は空間群Ｐｍ３ｍの立方晶系に分類することができる。 FIG. 10 shows a powder X-ray diffraction pattern. From this powder X-ray diffraction pattern, the synthesized MAPbBr 3 perovskite nanocrystals, FAPbBr 3 perovskite nanocrystals and CsPbBr 3 perovskite nanocrystals can be classified into the cubic system of the space group Pm3m.
　さらに、ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の入射光子束変調ＰＬ特性を調べるために、ガラス基板上にＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜を形成した。すなわち、図１１Ａに示すように、スライドガラス上に、中心に円形の井戸状の穴を有する正方形のシリコーンゴムを形成した。そして、そのシリコーンゴムの穴の中に、トルエン中にＭＡＰｂＢｒ3 ペロブスカイトナノ結晶を分散させることにより調製したペロブスカイトナノ結晶溶液（１ｍｇ／ｍＬ）を５０μＬ注入し、その上にカバーガラス（図示せず）を被せた後、乾燥させた。乾燥中にＭＡＰｂＢｒ3 ペロブスカイトナノ結晶が自己集合してＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜が形成された。図１１Ｂは紫外線ランプ（ＵＶランプ）下で撮影したＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の写真である。円形のＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜全体から緑色で発光している様子が観察された。 Furthermore, in order to examine the incident photon flux modulation PL characteristics of MAPbBr 3 perovskite nano crystal thin film was formed MAPbBr 3 perovskite nano crystal thin film on a glass substrate. That is, as shown in FIG. 11A, a square silicone rubber having a circular well-shaped hole at the center was formed on a slide glass. Then, 50 μL of a perovskite nanocrystal solution (1 mg / mL) prepared by dispersing MAPbBr 3 perovskite nanocrystals in toluene was injected into the hole of the silicone rubber, and a cover glass (not shown) was placed thereon. After covering, it was dried. During drying, the MAPbBr 3 perovskite nanocrystals self-assembled to form a MAPbBr 3 perovskite nanocrystal thin film. FIG. 11B is a photograph of a MAPbBr 3 perovskite nanocrystal thin film taken under an ultraviolet lamp (UV lamp). It was observed that the whole circular MAPbBr 3 perovskite nanocrystal thin film emitted green light.
　スライドガラス上に形成されたＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜を４００ｎｍのフェムト秒レーザーで光励起して挙動を調べた。ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜のＰＬ特性に対する入射光子束の影響を観察するために、入射レーザービームのフルエンス（単位面積当たりのエネルギー）を０．０１７ＭＷｃｍ-2から１７０ＭＷｃｍ-2の範囲まで系統的に増加させた。図１２に示すように、入射光子束の増加に伴い緑色発光の強度が徐々に増加するのが観測された。図１３に示すように、この増加は、ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の入射光子束に依存するＰＬスペクトルの変化として記録された。ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜およびＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜についても、いずれもレーザーフルエンスを増加した時に、同様な結果が得られた。ＰＬ強度のレーザーフルエンスに依存する増加は、光照射により発生した荷電キャリアーあるいは電子－正孔（ｅ－ｈ）対の濃度および放射性再結合の速度の増加を示す。 The MAPbBr 3 perovskite nanocrystal thin film formed on the slide glass was photoexcited with a femtosecond laser of 400 nm to investigate the behavior. In order to observe the effect of incident photon flux on PL characteristics of MAPbBr 3 perovskite nanocrystalline thin films, the fluence (energy per unit area) of the incident laser beam was systematically increased from 0.017 MWcm -2 to 170 MWcm -2. Let As shown in FIG. 12, it was observed that the intensity of green light emission gradually increased as the incident photon flux increased. As shown in FIG. 13, this increase was recorded as a change in PL spectrum depending on the incident photon flux of the MAPbBr 3 perovskite nanocrystal thin film. For even FAPbBr 3 perovskite nano crystal thin film and CsPbBr 3 perovskite nano crystal thin film, either when increasing the laser fluence, similar results were obtained. The laser fluence-dependent increase in PL intensity indicates an increase in the concentration of charge carriers or electron-hole (eh) pairs generated by light irradiation and the rate of radiative recombination.
　低レーザーフルエンスにおいて発生した低密度の荷電キャリアーの異常に遅延した（ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜では１．８６μｓ、ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜では９１５ｎｓ）再結合を観察した。ペロブスカイトの大きな単結晶およびバルク薄膜における光生成電荷のそのような遅延した再結合は励起の自由拡散と考えられている。上記のペロブスカイトナノ結晶薄膜における電荷の遅延した再結合は、ペロブスカイトナノ結晶間のキャリアー拡散の枠組みで考えることができる。一方、最小の励起（０．０１７ＭＷｃｍ-2）を行った、溶液中の分離されたペロブスカイトナノ結晶あるいは基板上のペロブスカイトナノ結晶の放射性再結合の高い速度（ｋr ＝０．７～１×１０8 ｓ-1）に基づき、粒子内の遅延した緩和の可能性を除外することができる。興味深いことに、ペロブスカイトナノ結晶薄膜におけるこれらの電荷の再結合は光照射により発生した荷電キャリアーの密度とともに増加する。これは、図１４に示すＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の高速のＰＬ減衰プロファイルならびに図１５Ａ、図１５Ｂ、図１５Ｃおよび図１５Ｄに示すＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜に対する時間－スペクトル分解光子計測マップから明らかである。ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の場合、平均ＰＬ寿命は、入射光子束が０．０１７ＭＷｃｍ-2から１７０ＭＷｃｍ-2に増加するにつれて１．８６μｓから２８ｎｓに減少する。ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の場合、平均ＰＬ寿命は、入射光子束が０．０１７ＭＷｃｍ-2から１７０ＭＷｃｍ-2に増加するにつれて９１５ｎｓから２４ｎｓに減少する。これらの結果は、励起光子束と、荷電キャリアーの密度および拡散と、放射緩和速度との間の強い関係を示唆する。これを図１６、図１７および図１８の片対数プロットにまとめる。 Anomalous delayed recombination (1.86 μs for FAPbBr 3 perovskite nanocrystal thin film and 915 ns for MAPbBr 3 perovskite nanocrystal thin film) of low density charge carriers generated at low laser fluence was observed. Such delayed recombination of photogenerated charges in large single crystal and bulk thin films of perovskites is considered to be free diffusion of excitation. The delayed recombination of charges in the above perovskite nanocrystal thin film can be considered in the framework of carrier diffusion between perovskite nanocrystals. On the other hand, the high rate of radiative recombination (k r = 0.7 to 1 × 10) of the separated perovskite nanocrystals in solution or perovskite nanocrystals on the substrate, which was subjected to minimum excitation (0.017 MWcm −2 ). Based on 8 s −1 ), the possibility of delayed relaxation within particles can be ruled out. Interestingly, the recombination of these charges in perovskite nanocrystal thin films increases with the density of charge carriers generated by light irradiation. This is apparent from the fast PL decay profile of the MAPbBr 3 perovskite nanocrystal thin film shown in FIG. 14 and the time-spectrum resolved photon measurement map for the FAPbBr 3 perovskite nanocrystal thin film shown in FIGS. 15A, 15B, 15C and 15D. is there. For FAPbBr 3 perovskite nanocrystal thin films, the average PL lifetime decreases from 1.86 μs to 28 ns as the incident photon flux increases from 0.017 MWcm −2 to 170 MWcm −2 . For MAPbBr 3 perovskite nanocrystal thin films, the average PL lifetime decreases from 915 ns to 24 ns as the incident photon flux increases from 0.017 MWcm −2 to 170 MWcm −2 . These results suggest a strong relationship between excited photon flux, charge carrier density and diffusion, and radiative relaxation rates. This is summarized in the semi-logarithmic plots of FIGS. 16, 17 and 18.
　低レーザーフルエンス（低パワー密度）における遅延キャリアー再結合および高レーザーフルエンス（高パワー密度）における放射性再結合の増速を光生成およびペロブスカイトナノ結晶薄膜における電荷キャリアーの光学的に制御された閉じ込めにより解釈する。図１９Ａおよび図１９Ｂはそれぞれ、低レーザーフルエンスおよび高レーザーフルエンスにおいてペロブスカイトナノ結晶薄膜に発生した荷電キャリアーの挙動を模式的に示す。ペロブスカイトナノ結晶薄膜に高レーザーフルエンス（１７０ＭＷｃｍ-2）を照射すると照射領域におけるペロブスカイトナノ結晶間で多数の荷電キャリアーが発生する（図１９Ｂ参照）。低レーザーフルエンス（０．０１７ＭＷｃｍ-2）では、光生成された荷電キャリアーの密度は低いので、キャリアー－キャリアー相互作用を最小化し、再結合前に薄膜中の長距離キャリアー拡散が可能となる（図１９Ａ参照）。そのような長距離拡散のため、低入射光子束で励起されたペロブスカイトナノ結晶薄膜は予期しない長いキャリアー（ＰＬ）寿命を示す。一方、入射レーザーフルエンスを増加させることにより、光生成荷電キャリアーの拡散はそれの密度の急増により空間的に制御される。その結果、照射領域内のそれらの再結合の速度は、大面積の領域に亘る拡散を支配し、ＰＬ寿命の減少が明確に観察される（図１４参照）。ここでは、放射性再結合が支配的な過程となり、これは約２ＭＷｃｍ-2のしきい値パワーを超える増幅放射から明らかである（図１３、図１６～図１８参照）。増幅放射はペロブスカイトナノ結晶間のキャリアー密度の増加および蓄積されたキャリアー間の非対（non-geminate) 放射性再結合の速度の増加によるものである。ここでは、ナノ結晶の集団励起のためにスペクトルの狭小化あるいはレーザー発振は観察されない。 Interpretation of delayed carrier recombination at low laser fluence (low power density) and radiative recombination enhancement at high laser fluence (high power density) by photoproduction and optically controlled confinement of charge carriers in perovskite nanocrystalline thin films To do. 19A and 19B schematically show the behavior of charge carriers generated in the perovskite nanocrystal thin film at low laser fluence and high laser fluence, respectively. When the perovskite nanocrystal thin film is irradiated with high laser fluence (170 MWcm −2 ), a large number of charge carriers are generated between the perovskite nanocrystals in the irradiation region (see FIG. 19B). At low laser fluence (0.017 MWcm -2 ), the low density of photogenerated charge carriers minimizes carrier-carrier interactions and allows long-range carrier diffusion in thin films before recombination (Figure 19A). Due to such long-range diffusion, perovskite nanocrystal thin films excited with low incident photon flux show unexpectedly long carrier (PL) lifetimes. On the other hand, by increasing the incident laser fluence, the diffusion of photogenerated charge carriers is spatially controlled by the sharp increase in their density. As a result, the rate of their recombination within the illuminated region dominates the diffusion over a large area and a decrease in PL lifetime is clearly observed (see Figure 14). Here, radiative recombination becomes the dominant process, which is evidenced by amplified radiation above a threshold power of approximately 2 MWcm -2 (see Figures 13 and 16-18). Amplified emission is due to an increase in carrier density between perovskite nanocrystals and an increase in the rate of non-geminate radiative recombination between accumulated carriers. Narrowing of the spectrum or lasing is not observed here due to the collective excitation of the nanocrystals.
　ペロブスカイトナノ結晶薄膜における、入射光子束により制御された荷電キャリアーの蓄積に関する上記のメカニズムを検証するため、蛍光マスキングおよび非マスキング実験を行った。この実験は、選択された領域から発生する光子を収集することにより時間分解ＰＬ測定を行う装置を設計して組み立てたものを用いて行った。図２０Ａに示すように、マスクをしない実験の間は、光子は、アイリスで制御される中央の照射領域（半径約５０μｍ）から収集した。一方、図２０Ｂに示すように、マスクをする実験の間は、スライドガラス上に取り付けた黒い紙で中央の照射領域（幅７５μｍ）をマスクし、外側の非照射領域から発生する光子を収集した。すなわち、この実験では、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の時間分解ＰＬ測定を、図１９Ａおよび図２０Ａに示すように、照射領域あるいは非照射領域からの低入射光子束および高入射光子束での放出光子を選択的に収集することにより行った。図２１に示すように、低レーザーフルエンスでは、照射領域におけるペロブスカイトナノ結晶の放射性寿命（τav＝５４０ｎｓ）（図２１の（２））は非照射領域における放射性寿命（τav＝８７０ｎｓ）（図２１の（１））よりも短く、入射光子束が１７０ＭＷｃｍ-2に増加するに従って指数関数的に５０ｎｓにさらに減少する（図２１の（３））。それにもかかわらず、マスキングを行わないでも、異なる遅延時間で放出された光子を正確に区別することができなかった（図２２参照）。興味深いことに、図２３に示すように、マスクをし、かつ低入射光子束では、非照射領域から得られた発光スペクトル（図２３の（１））は、照射領域から得られた発光スペクトル（図２３の（２））に比べて赤方変位（長波長側に変位）した。照射領域の外部で検出されたＰＬは、それは遅延放射性再結合の結果であるが、低レーザーフルエンスで発生した低密度荷電キャリアーの広範囲に亘る拡散を裏付けている。しかしながら、放射性再結合の速度は、レーザー照射領域では外側に比べていつも高い。この速度は、高入射光子束では著しく増加するが（図２１参照）、これは、ＰＬ寿命の著しい減少から明らかなように、高密度荷電キャリアーの空間的な閉じ込めによるものである。照射領域に比べて非照射領域から検出されたＰＬ最大値が赤方変位するのは、光発生した電子および正孔が長距離を移動する間のエネルギー損失によるものである。遅延放射およびエネルギー損失は長距離キャリアー移動を促進する粒子間状態の存在を示唆している。それにもかかわらず、荷電キャリアーの移動の範囲は、もっぱら薄膜中のペロブスカイトナノ結晶の充填密度によるものであり、これは、高密度（最密）（close-packed) および低密度（loose-packed) に充填された薄膜のＰＬスペクトルを記録することにより調べることができる。このために、実施例３と同様な方法を用い、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶のコロイド溶液の濃度を制御することにより、高密度ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜および密度が異なる４種類の低密度ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜を作製した。高密度ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の作製に用いたコロイド溶液の濃度は１ｍｇ／ｍＬ、低密度ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の作製に用いたコロイド溶液の濃度は、最も密度が高いものから順に、０．５ｍｇ／ｍＬ、０．２５ｍｇ／ｍＬ、０．１２５ｍｇ／ｍＬ、０．０６２ｍｇ／ｍＬとした。図２４に、これらの高密度ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜および低密度ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜のＰＬスペクトルを示す。図２４に示すように、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶の密度が低い低密度ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜のＰＬスペクトルは常に高エネルギー側にシフトするが、ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶の密度が高い高密度ＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜のＰＬスペクトルは常に低エネルギー側にシフトする。対応するＰＬ減衰プロファイルを図２５に示す。興味深いことに、赤方変位したＰＬスペクトルは常にＰＬ寿命の増加を伴う。放射光子のエネルギーとＰＬ寿命との間の逆の関係は、薄膜中のペロブスカイトナノ結晶間に亘って形成された状態を通しての荷電キャリアーの拡散で考えることができる。図２６Ａ、図２６Ｂ、図２６Ｃおよび図２６Ｄは、実施例２で作製したＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜へのレーザーフルエンスを４水準に変化させた時の時間－スペクトル分解光子計測マップの変化を示し、レーザーフルエンスは図２６Ａでは０．０４３ＭＷｃｍ-2、図２６Ｂでは０．４３ＭＷｃｍ-2、図２６Ｃでは４．３ＭＷｃｍ-2、図２６Ｄでは４３ＭＷｃｍ-2である。 Fluorescence masking and non-masking experiments were performed to verify the above mechanism of incident photon flux controlled charge carrier accumulation in perovskite nanocrystalline thin films. This experiment was performed using a designed and assembled device for performing time-resolved PL measurements by collecting photons generated from selected areas. As shown in FIG. 20A, during the unmasked experiment, photons were collected from the central iris-controlled irradiation area (radius about 50 μm). On the other hand, as shown in FIG. 20B, during the masking experiment, the central irradiation area (width: 75 μm) was masked with black paper mounted on a slide glass, and photons generated from the outer non-irradiation area were collected. . That is, in this experiment, the time-resolved PL measurement of the FAPbBr 3 perovskite nanocrystal thin film was performed, as shown in FIG. 19A and FIG. Was selectively collected. As shown in FIG. 21, at low laser fluence, the radiative lifetime (τ av = 540 ns) of the perovskite nanocrystals in the irradiation region ((2) in FIG. 21) is the radiative lifetime in the non-irradiation region (τ av = 870 ns) (Fig. It is shorter than (1) of 21 and further decreases exponentially to 50 ns as the incident photon flux increases to 170 MWcm −2 ((3) of FIG. 21). Nevertheless, without masking it was not possible to accurately distinguish photons emitted at different delay times (see Figure 22). Interestingly, as shown in FIG. 23, with a mask and a low incident photon flux, the emission spectrum obtained from the non-illuminated region ((1) in FIG. 23) is the emission spectrum obtained from the illuminated region ( The red displacement (displacement to the long wavelength side) was made as compared with (2) in FIG. The PL detected outside the illuminated region, which is the result of delayed radiative recombination, confirms the widespread diffusion of low density charge carriers generated at low laser fluence. However, the rate of radiative recombination is always higher in the laser irradiated area than in the outside. This velocity increases significantly with high incident photon flux (see Figure 21), which is due to the spatial confinement of the dense charge carriers, as evidenced by the significant decrease in PL lifetime. The fact that the PL maximum value detected in the non-irradiated region is red-shifted compared to the irradiated region is due to energy loss during the long-distance travel of the photo-generated electrons and holes. Delayed emission and energy loss suggest the existence of interparticle states that facilitate long-range carrier migration. Nevertheless, the extent of charge carrier migration is solely due to the packing density of perovskite nanocrystals in thin films, which is dense (close-packed) and low-packed. It can be investigated by recording the PL spectrum of the thin film filled in For this, using the same method as in Example 3, FAPbBr 3 perovskite by controlling the concentration of the colloidal solution of nanocrystals, dense FAPbBr 3 perovskite nano crystal thin film and density of four different low density FAPbBr 3 perovskite A nanocrystal thin film was prepared. The concentration of the colloidal solution used to prepare the high-density FAPbBr 3 perovskite nanocrystal thin film was 1 mg / mL, and the concentration of the colloidal solution used to prepare the low-density FAPbBr 3 perovskite nanocrystal thin film was 0 in order from the highest density. It was set to 0.5 mg / mL, 0.25 mg / mL, 0.125 mg / mL, and 0.062 mg / mL. FIG. 24 shows PL spectra of these high-density FAPbBr 3 perovskite nanocrystal thin films and low-density FAPbBr 3 perovskite nanocrystal thin films. Fig As shown in 24, FAPbBr 3 perovskite PL spectrum of a low density low density FAPbBr 3 perovskite nanocrystals films of the nanocrystals is always shifted to a higher energy side, but, FAPbBr 3 perovskite nano dense density FAPbBr 3 crystals The PL spectrum of the perovskite nanocrystal thin film always shifts to the low energy side. The corresponding PL decay profile is shown in FIG. Interestingly, the red-shifted PL spectrum is always accompanied by an increase in PL lifetime. The inverse relationship between the energy of the emitted photons and the PL lifetime can be thought of as the diffusion of charge carriers through the states formed between the perovskite nanocrystals in the thin film. 26A, 26B, 26C and 26D show changes in the time-spectral resolved photon measurement map when the laser fluence of the CsPbBr 3 perovskite nanocrystal thin film prepared in Example 2 was changed to 4 levels. laser fluence 0.043MWcm -2 in FIG. 26A, 0.43MWcm -2 in FIG. 26B, FIG. 26C 4.3MWcm -2, a 43MWcm -2 in Figure 26D.
　キャリアーの寿命の、ＡＢＸ3 のＡサイトカチオン（Ｃｓ+ 、ＭＡ+ またはＦＡ+ ）との関係をさらに調べるために、全無機ＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の時間相関ＰＬ特性を調べ、ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜およびＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜のＰＬ特性と比較した。ＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜に対する入射レーザーフルエンスの増加に伴ってＰＬ寿命は減少し、ＰＬ強度は増加し、これはＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜およびＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜のＰＬ特性と一致しているが、ＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜に対して見積もられる最大ＰＬ寿命（５０ｎｓ）は無機－有機ペロブスカイトに対するものより２桁低い。頂点を共有するＰｂＢｒ6  4-８面体により形成される空隙を占めるＣｓ+ 、ＭＡ+ またはＦＡ+ のようなＡサイトカチオンがペロブスカイトナノ結晶の伝導帯の最小値の変調に対する役割は不明であり、ＰＬ寿命に対するカチオンの関係も未解明であ。ＣｓＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の寿命がＭＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜およびＦＡＰｂＢｒ3 ペロブスカイトナノ結晶薄膜の寿命と比べて予期しない程に短いことは、Ａサイト有機カチオン（ＭＡ+ またはＦＡ+ ）が、ペロブスカイトナノ結晶薄膜における広範囲に亘る電荷の拡散にとって好ましいことを示唆している。 To further investigate the relationship between carrier lifetime and A-site cation of ABX 3 (Cs + , MA + or FA + ), the time-correlated PL characteristics of all inorganic CsPbBr 3 perovskite nanocrystal thin films were investigated, and MAPbBr 3 perovskite nanoparticle was investigated. The PL characteristics of the crystalline thin film and the FAPbBr 3 perovskite nanocrystalline thin film were compared. CsPbBr 3 perovskite nano PL lifetime with increasing incident laser fluence to the crystal thin film is reduced, PL intensity increases, which is consistent with PL characteristics of MAPbBr 3 perovskite nano crystal thin film and FAPbBr 3 perovskite nano crystal thin film However, the maximum PL lifetime (50 ns) estimated for CsPbBr 3 perovskite nanocrystal thin films is two orders of magnitude lower than for inorganic-organic perovskites. The role of A-site cations, such as Cs + , MA + or FA + , that occupy the voids formed by the PbBr 6 4- octahedron sharing the apex on the modulation of the minimum of the conduction band of perovskite nanocrystals is unknown, The relationship of cations to PL lifetime has not been clarified. CsPbBr 3 it perovskite nano crystal thin film of short life enough unexpected compared to MAPbBr 3 perovskite nano crystal thin film and FAPbBr 3 perovskite nano crystal thin film of life, A site organic cation (MA + or FA +) is, perovskite nano It suggests that it is preferable for diffusion of charge over a wide range in the crystalline thin film.
　実施例４で作製されたＭＡＰｂＩ3 ペロブスカイトナノ結晶について上述と同様なＵＶ－Ｖｉｓ吸収およびＰＬ分光により評価を行った。そのために、実施例４で作製されたＭＡＰｂＩ3 ペロブスカイトナノ結晶をトルエンに１０μｇ／ｍＬの濃度に分散させたコロイド溶液を作製した。図２７は、このコロイド溶液のＵＶ－Ｖｉｓ吸収スペクトルおよびＰＬスペクトルを示す。図２７に示すように、ヘキサデシルアミンおよびオレイン酸でキャップされたＭＡＰｂＩ3 ペロブスカイトナノ結晶は特に安定なフォトルミネッセンスを示す。図２８は、図２７に示す合成直後のＭＡＰｂＩ3 ペロブスカイトナノ結晶のコロイド溶液のＰＬスペクトルに、合成から２ヶ月間保管した後に測定したＭＡＰｂＩ3 ペロブスカイトナノ結晶のコロイド溶液のＰＬスペクトルを重ねたものである。図２８から明らかように、２ヶ月経過後でもＭＡＰｂＩ3 ペロブスカイトナノ結晶のＰＬスペクトルの強度およびプロファイルとも実質的に変化していない。 The MAPbI 3 perovskite nanocrystals produced in Example 4 were evaluated by the same UV-Vis absorption and PL spectroscopy as described above. Therefore, a colloidal solution was prepared in which the MAPbI 3 perovskite nanocrystal prepared in Example 4 was dispersed in toluene at a concentration of 10 μg / mL. FIG. 27 shows the UV-Vis absorption spectrum and PL spectrum of this colloidal solution. As shown in FIG. 27, MAPbI 3 perovskite nanocrystals capped with hexadecylamine and oleic acid show particularly stable photoluminescence. FIG. 28 shows a PL spectrum of the colloidal solution of MAPbI 3 perovskite nanocrystals immediately after synthesis shown in FIG. 27 and a PL spectrum of the colloidal solution of MAPbI 3 perovskite nanocrystals measured after storage for 2 months from the synthesis. is there. As is clear from FIG. 28, the PL spectrum intensity and profile of the MAPbI 3 perovskite nanocrystal did not substantially change even after 2 months.
　実施例５で作製されたＭＡＰｂＸ3 ペロブスカイトナノ結晶について上述と同様なＵＶ－Ｖｉｓ吸収およびＰＬ分光により評価を行った。そのために、実施例５で作製されたＭＡＰｂＸ3 ペロブスカイトナノ結晶をトルエンに１０μｇ／ｍＬの濃度に分散させたコロイド溶液を作製した。図２９、図３０および図３１はこのコロイド溶液のＵＶ－Ｖｉｓ吸収スペクトルおよびＰＬスペクトルを示し、それぞれＸ＝Ｃｌ，Ｘ＝ＢｒおよびＸ＝Ｉの場合である。図２９～図３１に示すように、ＭＡＰｂＣｌ3 ペロブスカイトナノ結晶、ＭＡＰｂＢｒ3 ペロブスカイトナノ結晶およびＭＡＰｂＩ3 ペロブスカイトナノ結晶のいずれも、良好なＰＬスペクトルが得られている。 The MAPbX 3 perovskite nanocrystals produced in Example 5 were evaluated by the same UV-Vis absorption and PL spectroscopy as described above. For that purpose, a colloidal solution was prepared in which the MAPbX 3 perovskite nanocrystals prepared in Example 5 were dispersed in toluene at a concentration of 10 μg / mL. 29, 30 and 31 show the UV-Vis absorption spectrum and PL spectrum of this colloidal solution, respectively for X = Cl, X = Br and X = I. As shown in FIGS. 29 to 31, good PL spectra were obtained for all of the MAPbCl 3 perovskite nanocrystals, the MAPbBr 3 perovskite nanocrystals and the MAPbI 3 perovskite nanocrystals.
　以上のように、この第１の実施の形態によれば、リガンド１０を介して互いに結合して二次元または三次元に配列したペロブスカイトナノ結晶２０からなる新規なペロブスカイトナノ結晶薄膜を実現することができる。このペロブスカイトナノ結晶薄膜は、量子ドットアレイとして使用可能であり、発光色の選択の範囲が広く、高輝度で光耐久性も高い高性能の発光ダイオードやレーザーなどの発光素子や、高効率で光耐久性も高い高性能の太陽電池などの光電変換素子あるいは光起電力素子を実現することができる。また、このペロブスカイトナノ結晶薄膜は簡単に製造することができる。 As described above, according to the first embodiment, it is possible to realize a novel perovskite nanocrystal thin film composed of the perovskite nanocrystals 20 that are bonded to each other via the ligand 10 and are arranged two-dimensionally or three-dimensionally. it can. This perovskite nanocrystal thin film can be used as a quantum dot array, has a wide range of selection of emission colors, has high brightness and high light durability, and has high efficiency. It is possible to realize a photoelectric conversion element or a photovoltaic element such as a high-performance solar cell having high durability. In addition, this perovskite nanocrystal thin film can be easily manufactured.
〈第２の実施の形態〉
［発光ダイオード］
　図３２は第２の実施の形態による発光ダイオードを示す。この発光ダイオードは第１の実施の形態によるペロブスカイトナノ結晶薄膜を発光層として用いたものである。 <Second Embodiment>
[Light emitting diode]
FIG. 32 shows a light emitting diode according to the second embodiment. This light emitting diode uses the perovskite nanocrystal thin film according to the first embodiment as a light emitting layer.
　図３２に示すように、発光ダイオードは、発光層として用いられるペロブスカイトナノ結晶薄膜１００が透明な電子注入層２００と正孔輸送層３００との間に挟まれた構造を有する。電子注入層２００には透明電極４００が設けられている。また、正孔輸送層３００には電極５００が設けられている。 As shown in FIG. 32, the light emitting diode has a structure in which a perovskite nanocrystal thin film 100 used as a light emitting layer is sandwiched between a transparent electron injection layer 200 and a hole transport layer 300. A transparent electrode 400 is provided on the electron injection layer 200. An electrode 500 is provided on the hole transport layer 300.
　電子注入層２００は、例えばＺｎＯからなる。正孔輸送層３００は、例えばＣＢＰ／ＭｏＯ3 からなる。ここで、ＣＢＰは４，４’－ビス（Ｎ－カルバゾリル）－１，１’－ビフェニル（４，４’-Bis(N-carbazolyl)-1，1 ’-biphenyl)である。透明電極４００は、例えばガラス基板上にインジウム－スズ酸化物（ＩＴＯ）がコーティングされたものからなる。 The electron injection layer 200 is made of ZnO, for example. The hole transport layer 300 is made of, for example, CBP / MoO 3 . Here, CBP is 4,4′-bis (N-carbazolyl) -1,1′-biphenyl (4,4′-Bis (N-carbazolyl) -1,1′-biphenyl). The transparent electrode 400 is made of, for example, a glass substrate coated with indium-tin oxide (ITO).
［発光ダイオードの製造方法］
　透明電極４００の全面に電子注入層２００、ペロブスカイトナノ結晶薄膜１００、正孔輸送層３００および電極５００を順次形成した後、これらをリソグラフィーおよびエッチングによりパターニングすることにより図３２に示す発光ダイオードを製造する。 [Method of manufacturing light emitting diode]
An electron injection layer 200, a perovskite nanocrystal thin film 100, a hole transport layer 300, and an electrode 500 are sequentially formed on the entire surface of the transparent electrode 400, and then these are patterned by lithography and etching to manufacture the light emitting diode shown in FIG. .
［発光ダイオードの動作］
　図３２に示すように、透明電極４００と電極５００との間に直流電圧を印加して電流を流すことによりペロブスカイトナノ結晶薄膜１００に電子注入層２００から電子（ｅ）を注入するとともに、正孔輸送層３００から正孔（ｈ）を注入する。こうしてペロブスカイトナノ結晶薄膜１００に注入された電子および正孔はペロブスカイトナノ結晶２０において再結合して発光が生じ、それによってペロブスカイトナノ結晶薄膜１００が発光し、透明電極４００を通して外部に光が取り出される。 [Operation of light emitting diode]
As shown in FIG. 32, a direct current voltage is applied between the transparent electrode 400 and the electrode 500 to cause a current to flow, thereby injecting electrons (e) from the electron injection layer 200 into the perovskite nanocrystal thin film 100 and at the same time, holes Holes (h) are injected from the transport layer 300. The electrons and holes thus injected into the perovskite nanocrystal thin film 100 are recombined in the perovskite nanocrystal 20 to generate light emission, whereby the perovskite nanocrystal thin film 100 emits light and the light is extracted to the outside through the transparent electrode 400.
　以上のように、この第２の実施の形態によれば、ペロブスカイトナノ結晶薄膜１００を発光層とする、発光色の選択の範囲が広く、高輝度で光耐久性も高い高性能の新規な発光ダイオードを実現することができる。 As described above, according to the second embodiment, the perovskite nanocrystal thin film 100 is used as the light emitting layer, the emission color selection range is wide, and the high-performance novel light emission with high brightness and high light durability is provided. A diode can be realized.
　以上、この発明の実施の形態および実施例について具体的に説明したが、この発明は、上述の実施の形態および実施例に限定されるものではなく、この発明の技術的思想に基づく各種の変形が可能である。 The embodiments and examples of the invention have been specifically described above, but the invention is not limited to the above-described embodiments and examples, and various modifications based on the technical idea of the invention. Is possible.
　例えば、上述の実施の形態および実施例において挙げた数値、材料、構成、配置、プロセスなどはあくまでも例に過ぎず、必要に応じて、これらと異なる数値、材料、構成、配置、プロセスなどを用いてもよい。 For example, the numerical values, materials, configurations, arrangements, processes, etc. mentioned in the above-described embodiments and examples are merely examples, and different numerical values, materials, configurations, arrangements, processes, etc. may be used as necessary. May be.
　１０　リガンド
　２０　ペロブスカイトナノ結晶
　１００　ペロブスカイトナノ結晶薄膜 10 ligand 20 perovskite nanocrystal 100 perovskite nanocrystal thin film

Claims (11)

  1. 　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜。 A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I), a perovskite nanocrystal thin film composed of perovskite nanocrystals.
  2. 　上記リガンドは、オレイン酸と、Ｙ－（ＣＨ2 ）n －ＮＨ2 （ただし、Ｙ＝ＨまたはＮＨ2 、ｎ＝６，８，９，１０，１１，１２，１３，１４，１５，１６，１８，２０，２１，３４）、Ｙ－（ＣＨ2 ）n －Ｙ（ただし、Ｙ＝ＮＨ2 、ｎ＝４，５，６，７，８，９，１０，１１，１２，１３，１４，１５，１６，１８，２０，２１，３４）、Ｚ－（ＣＨ2 ）n －Ｚ（Ｚ＝ＣＯＯＨ、ｎ＝４，５，６，７，８，９，１０，１１，１２，１３，１４，１５，１６，１８，２０，２１，３４）およびオレイルアミンからなる群から選択された少なくとも一つとからなる請求項１記載のペロブスカイトナノ結晶薄膜。 The ligand is oleic acid and Y- (CH 2 ) n- NH 2 (where Y = H or NH 2 , n = 6,8,9,10,11,12,13,14,15,16, 18, 20, 21, 34), Y- (CH 2 ) n -Y (where Y = NH 2 , n = 4,5,6,7,8,9,10,11,12,13,14, 15,16,18,20,21,34), Z- (CH 2 ) n -Z (Z = COOH, n = 4,5,6,7,8,9,10,11,12,13,14) , 15, 16, 18, 18, 20, 21, 34) and at least one selected from the group consisting of oleylamines.
  3. 　上記ペロブスカイトナノ結晶は立方体の形状を有する請求項１記載のペロブスカイトナノ結晶薄膜。 The perovskite nanocrystal thin film according to claim 1, wherein the perovskite nanocrystal has a cubic shape.
  4. 　上記ペロブスカイトナノ結晶の大きさは５ｎｍ以上１５ｎｍ以下である請求項１記載のペロブスカイトナノ結晶薄膜。 The perovskite nanocrystal thin film according to claim 1, wherein the size of the perovskite nanocrystal is 5 nm or more and 15 nm or less.
  5. 　上記ペロブスカイトナノ結晶間の距離が２ｎｍ以上５ｎｍ以下である請求項１記載のペロブスカイトナノ結晶薄膜。 The perovskite nanocrystal thin film according to claim 1, wherein the distance between the perovskite nanocrystals is 2 nm or more and 5 nm or less.
  6. 　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜の製造方法であって、
    　上記リガンドが結合した上記ペロブスカイトナノ結晶を溶媒に分散させた溶液を基板に付着させる工程と、
    　上記基板に付着した上記溶液を乾燥させることにより上記リガンドが結合した上記ペロブスカイトナノ結晶を自己集合させて上記リガンドを介して互いに結合した上記ペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜を形成する工程と
    を有することを特徴とするペロブスカイトナノ結晶薄膜の製造方法。     A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I), a perovskite nanocrystal thin film comprising a perovskite nanocrystal represented by:
    Attaching a solution in which the perovskite nanocrystals bound with the ligand are dispersed in a solvent to a substrate,
    Forming a perovskite nanocrystal thin film consisting of the perovskite nanocrystals bonded to each other via the ligand by self-assembling the perovskite nanocrystals bound with the ligand by drying the solution attached to the substrate. A method of manufacturing a perovskite nanocrystal thin film, comprising:
  7. 　ＡＸとＢＸ2 とＹ－（ＣＨ2 ）n －ＮＨ2 とオレイン酸とを溶媒に溶解して前駆体溶液を作製する工程と、上記前駆体溶液から上記リガンドが結合した上記ペロブスカイトナノ結晶を析出させる工程とを順次実行することにより、上記リガンドが結合した上記ペロブスカイトナノ結晶を形成する請求項６記載のペロブスカイトナノ結晶薄膜の製造方法。 A step of preparing a precursor solution by dissolving AX, BX 2 , Y— (CH 2 ) n —NH 2 and oleic acid in a solvent, and depositing the perovskite nanocrystals bound with the ligand from the precursor solution The method for producing a perovskite nanocrystal thin film according to claim 6, wherein the perovskite nanocrystals to which the ligand is bound are formed by sequentially performing the step of performing.
  8. 　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜により形成された発光層を有する発光素子。 A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I), a light-emitting device having a light-emitting layer formed of a perovskite nanocrystal thin film composed of perovskite nanocrystals.
  9. 　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜により形成された光電変換層を有する光電変換素子。 A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I), a photoelectric conversion element having a photoelectric conversion layer formed of a perovskite nanocrystal thin film made of a perovskite nanocrystal.
  10. 　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜を有する表示装置。 A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I), a display device having a perovskite nanocrystal thin film composed of perovskite nanocrystals.
  11. 　リガンドを介して互いに結合して二次元または三次元に配列した複数の、化学式ＡＢＸ3 （ただし、Ａ＝ＣＨ3 ＮＨ3 ，Ｃｓ，ＣＨ（ＮＨ2 ）2 、Ｂ＝Ｐｂ，Ｃｄ，Ｓｂ，Ｂｉ，Ｓｎ、Ｘ＝Ｃｌ，Ｂｒ，Ｉ）で表されるペロブスカイトナノ結晶からなるペロブスカイトナノ結晶薄膜を有する電子機器。 A plurality of chemical formulas ABX 3 (where A = CH 3 NH 3 , Cs, CH (NH 2 ) 2 , B = Pb, Cd, Sb, Bi are bound to each other via a ligand and are arranged two-dimensionally or three-dimensionally. , Sn, X = Cl, Br, I), an electronic device having a perovskite nanocrystal thin film composed of perovskite nanocrystals.
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