Semiconductor Particles and Electronic Devices

Abstract

To provide semiconductor particles capable of achieving a light-emitting electronic device having a good chromatic purity of blue light emission, a high light emission efficiency and a long service life, and to provide an electronic device using the semiconductor particles.SOLUTION: Semiconductor particles include a semiconductor containing gallium, nitrogen, and indium or aluminum, and have an average particle diameter of 1-1,000 nm.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to semiconductor particles and electronic devices. [Background technology]

[0002] In recent years, there has been remarkable progress in organic light-emitting diodes (OLEDs) and the technology of organic EL display devices using them, but there are still some problems that have not been solved in the development of inexpensive liquid crystal displays. Among these, the organic light-emitting materials used in OLED displays have problems with color purity, luminous efficiency, and luminous life span of blue emitting materials, as well as problems with coating technology.

[0003] In fact, several proposals have been made to solve these problems. The first is an attempt to improve the luminous efficiency by using phosphorescent materials or delayed fluorescent materials. Both phosphorescent and delayed fluorescent materials have been successful in increasing the luminous efficiency by utilizing the energy of triplet levels (Patent Documents 1-2, Non-Patent Documents 1-2), but in the case of blue emitting materials, the emission wavelength range extends to the long wavelength side, which causes problems with color purity, and the luminous lifetime is short (1,000 cd / m 2 The initial brightness is about 1000 nm, and the half-life is about several hours), which is still not suitable for display applications.

[0004] The second is the attempt to use inorganic semiconductor particles with luminescent function as the active layer. As blue luminescent materials, those mainly based on cadmium sulfide, zinc sulfide, and zinc selenide have been tried (Non-Patent Document 3). The emission wavelength range is sharper than phosphorescence and delayed fluorescence materials, and the color purity is good, but the problem of a very short emission life remains.

[0005] The third issue is how to deal with coating techniques using polymeric materials. Polymeric coating materials also have problems with both luminous efficiency and luminous lifespan when used with blue luminescent materials, making them unsuitable for display applications.

[0006] On the other hand, although research and development related to renewable energy has been widely conducted in recent years, solar cell devices that can be fabricated by a simple, low-cost coating process have not yet reached a practical level.

[0007] Although single crystal silicon and single crystal III-V compound devices can realize solar cell devices with high efficiency and long life (Non-Patent Document 4), the manufacturing process is very expensive because it involves a high-temperature epitaxial growth process on a single crystal substrate. In order to enable a simple coating process on an inexpensive substrate such as glass, a low-temperature process mainly using polymer materials is required, but the power generation efficiency and durability are far from a practical level (Non-Patent Document 5).

[0008] In recent years, coating materials using III-V nanoparticles have been proposed for solar cells, and high power generation efficiency is expected, but a highly durable material has not yet been proposed (Non-Patent Document 6). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Special Publication No. 2004-506305 [Patent Document 2] JP 2004-199875 A [Patent Document 3] JP 2016-197601 A [Non-patent literature]

[0010] [Non-Patent Document 1] M. Groarke et.al. J Soc Inf Disp. 2012, Vol.20(1), p.70-78 [Non-Patent Document 2] T. Miwa et.al. Sci. Rep. 2017, Vol.7, Article number: 284 [Non-Patent Document 3] Y. Yang et. al. Nat. Photon. 2015, Vol.9(4), p.259-266 [Non-Patent Document 4] NEDO Renewable Energy Technology White Paper 2nd Edition (2014) Morikita Publishing [Non-Patent Document 5] Y. Zhang et.al. Advanced Science. 2018, Vol.5, p.1800434 [Non-Patent Document 6] OE Semonin et. al. Science. 2011, Vol.334, 1530 Summary of the Invention [Problem to be solved by the invention]

[0011] As described above, the organic light-emitting materials used in OLED displays have problems with color purity, luminous efficiency, and luminous lifespan of blue light-emitting materials.

[0012] The present invention has been made in view of the above problems, and aims to provide semiconductor particles capable of realizing a light-emitting electronic device having good color purity of blue light emission, high luminous efficiency, and long life, or a photovoltaic electronic device (solar cell device) having high efficiency and long life, and an electronic device using the semiconductor particles. Note that the light-emitting electronic device and the photovoltaic electronic device using the semiconductor particles according to the present invention are collectively referred to as "electronic device". [Means for solving the problem]

[0013] The present inventors have conducted extensive research to solve the above problems, and as a result, have found that the above problems can be solved by forming an active layer using semiconductor particles mainly containing indium, gallium, and nitrogen, thereby completing the present invention.

[0014] That is, the present invention is as follows. [1] Contains a semiconductor containing gallium, nitrogen, and indium or aluminum, The average particle size is 1 to 1000 nm. Semiconductor particles. [2] The semiconductor has the following composition formula (1): X a Ga b N C (In the formula, X represents indium or aluminum, and a, b, and c satisfy 0.7≦a+b≦1.5, 0.01≦a≦0.5, 0.2≦b≦1.49, and 0.8≦c≦1.2.) Represented by The semiconductor particles according to [1]. [3] The semiconductor has the following composition formula (2): X a Ga b N C (In the formula, X represents indium or aluminum, and a, b, and c satisfy a+b=1.0, 0.01≦a≦0.5, and c=1.) Represented by The semiconductor particles according to [1]. [4] The LUMO level is less than -2.0 eV, The band gap is 2.0 eV or more. The semiconductor particles according to any one of [1] to [3]. [5] having polar molecules on the surface, The semiconductor particles according to any one of [1] to [4]. [6] An organic solvent; and the semiconductor particles according to any one of [1] to [5], dispersed in the organic solvent. Semiconductor particle dispersion. [7] A dispersion step of obtaining a dispersion liquid in which a powder containing gallium, a nitrogen source, and a powder containing indium or a powder containing aluminum are dispersed in an organic solvent; The method includes irradiating the dispersion with light to obtain semiconductor particles containing a semiconductor including gallium, nitrogen, and indium or aluminum. A method for producing semiconductor particles. [8] In the irradiation step, irradiating the powder in the dispersion with laser light to obtain the semiconductor particles; A method for producing semiconductor particles according to [7]. [9] In the irradiation step, irradiating the powder in the dispersion with single wavelength light or multiple wavelength light, either individually or alternately, to obtain the semiconductor particles. A method for producing semiconductor particles according to [7] or [8].

[10] The dispersion contains dissolved nitrogen. The method for producing semiconductor particles according to any one of [7] to [9].

[11] The dispersion liquid comprises polar molecules. The method for producing semiconductor particles according to any one of [7] to

[10] .

[12] The dispersion liquid contains an amino group-containing compound. The method for producing semiconductor particles according to any one of [7] to

[11] .

[13] A step of flowing a gas containing nitrogen into the dispersion liquid. The method for producing semiconductor particles according to any one of [7] to

[12] .

[14] a cathode, an anode, and an active layer disposed between the cathode and the anode; The active layer contains the semiconductor particles according to any one of [1] to [5]. Electronic devices.

[15] The active layer contains 25% by volume or more of the semiconductor particles. The electronic device described in

[14] .

[16] The active layer contains 0.1 to 20% by volume of the semiconductor particles and 50% by volume or more of an organic host material. The electronic device described in

[14] .

[17] An electron transport layer or a hole transport layer is provided between the cathode or the anode and the active layer. The electronic device according to any one of

[14] to

[16] .

[18] A light-emitting device that emits light having a peak wavelength of 500 nm or less. The electronic device according to any one of

[14] to

[17] .

[19] It is a photovoltaic device that absorbs light and generates electricity. The electronic device according to any one of

[14] to

[16] . Effect of the Invention

[0015] According to the present invention, it is possible to provide semiconductor particles capable of realizing a light-emitting device that emits blue light with good color purity, has high luminous efficiency, and has a long lifetime, or a photovoltaic electronic device that is highly efficient and has a long lifetime, and an electronic device using the semiconductor particles. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is a diagram showing an example of a layer structure of an electronic device according to an embodiment of the present invention. [Diagram 2] 1 is a transmission electron microscope photograph of semiconductor particles contained in the transparent solution obtained in Example 1. [Diagram 3] 4 is a photograph showing luminescence from a semiconductor particle dispersion liquid according to the present embodiment. [Figure 4] FIG. 2 is a diagram showing an emission spectrum of a semiconductor particle dispersion liquid according to the embodiment. [Diagram 5] FIG. 2 is a diagram showing a layer structure of the light-emitting device produced in Example 2. [Figure 6] FIG. 4 is a graph showing the voltage-current characteristics and voltage-luminance characteristics of the light-emitting device prepared in Example 2. [Figure 7]FIG. 13 is a diagram showing the emission spectrum of the light-emitting device fabricated in Example 2. [Figure 8] 1 is a table showing basic characteristics of the light-emitting device fabricated in Example 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Below, we will explain in detail the embodiment of the present invention (hereinafter referred to as the "present embodiment"). However, the present invention is not limited to this embodiment, and various modifications are possible without departing from the gist of the present invention.

[0018] [Semiconductor particles] The semiconductor particles of this embodiment are characterized in that they contain a semiconductor containing gallium, nitrogen, and indium or aluminum, and have an average particle size of 1 to 1000 nm.

[0019] The semiconductor contained in the semiconductor particles of this embodiment is not particularly limited as long as it contains gallium, nitrogen, and indium or aluminum, but is preferably, for example, one represented by the following composition formula (1): By using semiconductor particles containing such a semiconductor, the color purity, luminous efficiency, and luminous life of blue light emission tend to be further improved. X a Ga b N C (1) (In the formula, X represents indium or aluminum, and a, b, and c satisfy 0.7≦a+b≦1.5, 0.01≦a≦0.5, 0.2≦b≦1.49, and 0.8≦c≦1.2.)

[0020] In the formula, a represents the proportion of indium (In) or aluminum (Al). From the viewpoints of color purity, luminous efficiency, and luminous life of blue light emission, a is preferably 0.01 to 0.5, more preferably 0.03 to 0.4, and further preferably 0.05 to 0.3.

[0021] In the formula, b represents the proportion of gallium (Ga). From the viewpoints of color purity, luminous efficiency, and luminous life of blue light emission, b is preferably 0.2 to 1.49, more preferably 0.4 to 1.3, and further preferably 0.6 to 1.1.

[0022] In the formula, c represents the proportion of nitrogen (N). From the viewpoints of color purity, luminous efficiency, and luminous life of blue light emission, c is preferably 0.8 to 1.2, more preferably 0.9 to 1.1, and further preferably 1.

[0023] From the viewpoints of color purity, luminous efficiency, and luminous life of blue light emission, the sum of a and b is preferably 0.7 to 1.5, more preferably 0.8 to 1.3, further preferably 0.9 to 1.1, and particularly preferably 1.

[0024] Among the above, semiconductor particles represented by the following composition formula (2) are preferred: By using such semiconductor particles, the color purity, luminous efficiency, and luminous life of blue light emission tend to be further improved. X a Ga b N C (2) (In the formula, X represents indium or aluminum, and a, b, and c satisfy a+b=1.0, 0.01≦a≦0.5, and c=1.)

[0025] In addition, the semiconductor particles of this embodiment include those composed of particles of the above-mentioned semiconductor containing gallium, nitrogen, and indium or aluminum, as well as semiconductor particles having a core-shell structure, in which the core contains the above-mentioned semiconductor containing gallium, nitrogen, and indium or aluminum, or semiconductor particles having the above-mentioned semiconductor containing gallium, nitrogen, and indium or aluminum in the shell.

[0026] In addition, as a semiconductor other than the above semiconductor containing gallium, nitrogen, and indium or aluminum, the semiconductor contained in the core or shell of the semiconductor particle of this embodiment is not particularly limited, but examples thereof include semiconductors using II-VI group elements such as CdSe, CdS, CdTe, ZnSe, ZnO, ZnS, ZnTe, HgS, HgSe, HgTe, etc.; semiconductors using III-V group elements such as InAs, InP, GaAs, GaP, InN, GaN, InSb, GaSb, AlP, AlAs, AlSb, etc.; semiconductors using IV-VI group elements such as PbSe, PbTe, PbS, etc.; semiconductors using III-VI group elements such as InSe, InTe, InS, GaSe, etc.; and semiconductors using IV group elements such as Si and Ge.

[0027] The average particle size of the semiconductor particles is 1 to 1000 nm, preferably 2 to 500 nm, more preferably 50 to 400 nm, further preferably 100 to 300 nm, and particularly preferably 100 to 200 nm. The larger the average particle size of the semiconductor particles, the longer the emission wavelength of the light-emitting device using the semiconductor particles, and the smaller the average particle size of the semiconductor particles, the shorter the emission wavelength tends to be. The semiconductor particles of this embodiment have an average particle size within the above range, so that the color purity of blue tends to be improved. The average particle size can be measured by the method described in the Examples. Semiconductor particles having an average particle size within a specific range can also be called "quantum dots".

[0028] If the width of the emission spectrum is narrow, the light approaches a specific monochromatic light and the color purity is high. On the other hand, if the width of the emission spectrum is wide, the light of various colors (wavelengths) tends to be mixed and the color purity tends to be low. From this point of view, it is preferable that the semiconductor particles are monodisperse.

[0029] The LUMO level of the semiconductor particles is preferably less than -2.0 eV, more preferably less than -2.8 eV, and even more preferably less than -3.0 eV. The lower limit of the LUMO level is not particularly limited, but is preferably greater than -4.0 eV. The LUMO level of less than -2.0 eV tends to improve the luminous efficiency and extend the luminous life.

[0030] The HOMO level of the semiconductor particles is preferably -6.5 eV or more, more preferably -6.0 eV or more. The upper limit of the HOMO level is not particularly limited, but is preferably -5.5 eV or less. When the HOMO level is -6.5 eV or more, the luminous efficiency tends to be further improved.

[0031] The band gap of the semiconductor particles is preferably 2.0 eV or more, more preferably 2.7 eV or more, and further preferably 2.8 eV or more. When the band gap is -2.0 eV or more, the emitted light color tends to have a short wavelength.

[0032] In this embodiment, the orbital energies (HOMO and LUMO) can be measured by photoelectron spectroscopy, and the band gap can be measured by absorption / emission spectroscopy.

[0033] The semiconductor particles preferably contain a semiconductor having the above composition and also have polar molecules on at least a part of the surface. By attaching polar molecules to at least a part of the surface of the semiconductor particles, the dispersibility of the semiconductor particles in a solution or polymer, and the color purity, luminous efficiency, or luminous life of the semiconductor particles when dispersed therein tend to be further improved.

[0034] The polar molecule is not particularly limited, but may be, for example, a molecule having an anchor group that is bonded to the semiconductor particle surface by a covalent bond or a coordinate bond, an organic functional group having a relatively high HOMO level, and a spacer group that connects the anchor group and the organic functional group. Here, the anchor group is not particularly limited, but may be, for example, a thiol group, and the organic functional group is not particularly limited, but may be, for example, a group containing amine, triarylamine, thiophene, carbazole, phthalocyanine, or porphyrin. In addition, the spacer group is not particularly limited, but may be, for example, an alkyl group.

[0035] [Semiconductor Particle Dispersion] The semiconductor particle dispersion of the present embodiment includes an organic solvent and the semiconductor particles dispersed in the organic solvent. By applying the semiconductor particle dispersion onto a substrate by spin coating or the like, a layer containing the semiconductor particles can be easily formed.

[0036] The organic solvent is not particularly limited, but examples thereof include alcohol-based solvents such as isopropyl alcohol; and aromatic solvents such as xylene.

[0037] The content of the semiconductor particles in the semiconductor particle dispersion, depending on the application of the semiconductor particle dispersion, is preferably 0.1 to 50 mass%, more preferably 0.5 to 40 mass%, and even more preferably 1 to 30 mass% based on the total amount of the semiconductor particle dispersion. By having the content of the semiconductor particles within the above range, the dispersion stability tends to be further improved. In addition, when used for applications such as spin coating, the content of the semiconductor particles in the semiconductor particle dispersion is preferably 0.1 to 5 mass%, more preferably 0.5 to 4 mass%, and even more preferably 1 to 3 mass% based on the total amount of the semiconductor particle dispersion. By having the content of the semiconductor particles within the above range, the coatability tends to be further improved.

[0038] The semiconductor particle dispersion liquid may contain other components. The other components are not particularly limited, but may include, for example, polar molecules, polymers, and surfactants.

[0039] [Method for producing semiconductor particles] Conventionally, chemical methods such as solution-phase colloidal methods are known as methods for producing semiconductor particles made of semiconductors. In this method, a nucleus of semiconductor nanocrystals is formed in a solution, and the nucleus is grown to obtain semiconductor particles. However, it is difficult to synthesize semiconductor particles containing semiconductors containing gallium, nitrogen, and indium or aluminum by this method, and the ones obtained by the above method are unstable and lose their luminescence quickly, and it is difficult to say that the semiconductors containing gallium, nitrogen, and indium or aluminum are properly synthesized in terms of their performance.

[0040] This embodiment relates to a novel synthesis method using a liquid phase laser ablation method as a method for synthesizing semiconductor particles containing a semiconductor containing gallium, nitrogen, and indium or aluminum. That is, the method for producing semiconductor particles of this embodiment includes a dispersion step of obtaining a dispersion liquid in which a powder containing gallium, a nitrogen raw material, and a powder containing indium or a powder containing aluminum are dispersed in an organic solvent, and an irradiation step of irradiating the dispersion liquid with light to obtain semiconductor particles containing a semiconductor containing gallium, nitrogen, and indium or aluminum.

[0041] (Dispersion process) The dispersion step is a step of obtaining a dispersion liquid in which a powder containing gallium, a nitrogen raw material, and a powder containing indium or a powder containing aluminum are dispersed in an organic solvent.The method of preparing the dispersion liquid is not particularly limited, and includes a method of adding each raw material to an organic solvent and mixing it, high-speed stirring, a bead mill, a jet mill, a planetary mill, etc.

[0042] The organic solvent is not particularly limited, but examples thereof include alcohol-based solvents such as isopropyl alcohol.

[0043] The powder containing gallium is not particularly limited, but may be, for example, gallium nitride powder. The powder containing indium is not particularly limited, but may be, for example, indium nitride powder. The powder containing aluminum is not particularly limited, but may be, for example, aluminum nitride powder. The nitrogen source is not particularly limited, but may be, for example, gallium nitride powder, indium nitride powder, aluminum nitride powder, etc. The powder containing gallium, the nitrogen source, the powder containing indium, and the powder containing aluminum may be different compounds or the same compound. For example, since gallium nitride powder corresponds to both the powder containing gallium and the nitrogen source, if gallium nitride powder is used, it can be considered that the powder containing gallium and the nitrogen source are both used in the dispersion process. Among these, it is preferable to use gallium nitride powder and indium nitride powder in combination. In addition, an indium organic compound and a gallium organic compound can be used.

[0044] In addition, the dispersion liquid may contain an amino group-containing compound such as ammonia, a raw material containing nitrogen, or nitrogen in the form of dissolved nitrogen, from the viewpoint of complementing N defects in the semiconductor particles when the semiconductor particles are generated. In addition, when using dissolved nitrogen, it is considered to add nitrogen to the dispersion liquid by performing a process of blowing nitrogen gas into the dispersion liquid. In addition, the amino group-containing compound may contain a solvent having an amino group, and dimethylformamide, pyridine, etc. can be used.

[0045] When gallium nitride powder and indium nitride powder are used in combination, the mass ratio can be adjusted depending on the composition of the semiconductor constituting the semiconductor particles. From the viewpoint of reaction efficiency, the total content of the gallium-containing powder, the nitrogen raw material, and the indium-containing powder or the aluminum-containing powder is preferably 1 to 50 mass%, more preferably 3 to 40 mass%, and even more preferably 5 to 30 mass% based on the total amount of the dispersion.

[0046] In addition to the above, the dispersion liquid may contain polar molecules. The polar molecules are not particularly limited, but examples thereof include those mentioned above.

[0047] (irradiation process) The irradiation step is a step of obtaining semiconductor particles by irradiating the powder in the dispersion with light. The energy of the light irradiation causes the powder containing gallium, the nitrogen raw material, and the powder containing indium or the powder containing aluminum to react with each other to form semiconductor particles. The light to be irradiated includes laser light such as a solid-state laser such as YAG, a semiconductor laser such as GaAs or InGaAsP, and a gas laser such as KrF. Among these, a solid-state laser is preferable. By using such light, semiconductor particles tend to be synthesized more efficiently.

[0048] A method has been known in which a solid target is irradiated with high-density laser light in a solution to induce a plasma state and produce fine particles of a material with the same composition. Also, a method has been known in which particles in a liquid are irradiated with laser light to granulate a material with the same composition. The liquid phase laser ablation method used in this embodiment is a method in which a raw material in a solution is irradiated with laser light to micronize the material and simultaneously react with a different material to synthesize a new material.

[0049] In addition, examples of the light irradiation method include a method of continuously irradiating light of a single wavelength, a method of continuously irradiating light of multiple wavelengths, a method of intermittently irradiating light of a single wavelength, a method of intermittently irradiating light of multiple wavelengths, a method of alternately irradiating light of a single wavelength and light of multiple wavelengths, a method of alternately irradiating light of two or more single wavelengths with different wavelengths, and a method of alternately irradiating light of two or more multi-wavelengths with different wavelengths. By using such a method, semiconductor particles tend to be synthesized more efficiently.

[0050] The wavelength of the irradiated light is preferably 150 to 1100 nm, more preferably 193 to 800 nm, and further preferably 193 to 400 nm. By setting the wavelength within the above range, the semiconductor particles tend to be synthesized more efficiently.

[0051] The pulse width of the irradiated laser can be femtoseconds, picoseconds, or nanoseconds, and is preferably 5 to 300 ns, more preferably 10 to 100 ns, and further preferably 10 to 50 ns. By setting the pulse width within the above range, semiconductor particles tend to be synthesized more efficiently.

[0052] Moreover, the laser output per irradiated pulse is preferably 30 to 250 mJ, more preferably 40 to 200 mJ, and further preferably 50 to 150 mJ. By setting the output within the above range, semiconductor particles tend to be synthesized more efficiently.

[0053] The light irradiation time varies depending on the type of light to be irradiated and the amount of dispersion to be treated, but is preferably 0.25 to 3 hours, more preferably 0.5 to 2 hours, and further preferably 0.75 to 1.5 hours. By setting the irradiation time within the above range, semiconductor particles tend to be synthesized more efficiently.

[0054] [Electronic Devices] The electronic device of this embodiment includes a cathode 1, an anode 2, and an active layer 3 disposed between the cathode 1 and the anode 2, and the active layer 3 includes the above-mentioned semiconductor particles. When the electronic device of this embodiment is a light-emitting device, the active layer functions as a light-emitting layer, and when the electronic device is a photovoltaic device, the light-emitting layer functions as a photovoltaic layer. An example of the layer structure of the electronic device is shown in Figure 1.

[0055] In one embodiment, the content of the semiconductor particles in the active layer 3 is preferably 0.1 to 20 volume %, more preferably 0.5 to 17.5 volume %, and even more preferably 1 to 15 volume %, relative to the total volume of the active layer 3.

[0056] In another embodiment, the content of the semiconductor particles in the active layer 3 is preferably 20 to 25% by volume, and more preferably 21 to 24% by volume, based on the total volume of the active layer 3.

[0057] In another embodiment, the content of the semiconductor particles in the active layer 3 is preferably 25 vol% or more, more preferably 27.5 vol% or more, and even more preferably 30 vol% or more, based on the total volume of the active layer 3. In this embodiment, the upper limit of the content of the semiconductor particles in the active layer 3 is not particularly limited, but is preferably 90 vol% or less, more preferably 80 vol% or less, and even more preferably 70 vol% or less.

[0058] Other components constituting the active layer 3 are not particularly limited, but may include, for example, t-butylphenyl biphenyl oxadiazole (t-PBD) as an organic host material.

[0059] Although not shown in FIG. 1, the electronic device of this embodiment may have an electron transport layer or a hole transport layer between the cathode 1 and the active layer 3 and / or between the anode 2 and the active layer 3.

[0060] The components constituting the hole transport layer are not particularly limited and may be components used in hole transport layers of conventional electronic devices, and examples thereof include amines, triarylamines, thiophenes, carbazoles, phthalocyanines, porphyrins, and isomers and derivatives thereof.

[0061] The components constituting the electron transport layer are not particularly limited and may be components used in electron transport layers of conventional electronic devices, and examples thereof include imidazole, pyridine, pyrimidine, pyridazine, pyrazine, oxadiazole, quinoline, quinoxaline, anthracene, benzanthracene, pyrene, perylene, benzimidazole, triazine, ketone, phosphinoxide, phenazine, phenanthroline, triarylborane, and isomers and derivatives thereof.

[0062] The electronic device of this embodiment may also have a hole injection layer or a charge generation layer between the cathode 1 and the active layer 3 and / or between the anode 2 and the active layer 3. The components constituting the hole injection layer or the charge generation layer are not particularly limited, and known materials can be used.

[0063] When the electronic device of this embodiment is a light-emitting device, the peak wavelength of the light emitted by the light-emitting device is preferably 500 nm or less, more preferably 400 to 490 nm, and further preferably 430 to 485 nm. The peak wavelength of the light emitted by the light-emitting device can be adjusted by the indium concentration and the size of the semiconductor particles.

[0064] The electronic device of the present embodiment is not limited to a light-emitting device, and may be, for example, a light-receiving device. Here, the light-receiving device may be a photovoltaic device (solar cell) that absorbs light and generates electricity. When the electronic device is a light-receiving device, the semiconductor particles of the present embodiment can be used as a photovoltaic material that receives light. EXAMPLES

[0065] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples.

[0066] Example 1 250 mg of gallium nitride powder and 50 mg of indium nitride powder were added to 20 mL of isopropyl alcohol to prepare a mixture. While stirring this mixture with a stirrer, a krypton fluoride (KrF) excimer laser was irradiated from above the liquid surface. As a result, In 0.1 Ga 0.9 A transparent solution was obtained in which N-composition semiconductor particles were dispersed. The irradiation conditions are as follows: (Irradiation conditions) Output: 100mJ / 1 pulse Oscillation wavelength: 148 nm Frequency: 2Hz Irradiation time: 2 hours

[0067] The obtained transparent solution was evaluated using a particle size meter (Otsuka Electronics Co., Ltd., product name ELSZ-1000), and it was found that semiconductor particles having an average particle size of 300 nm were dispersed therein.

[0068] Furthermore, the obtained transparent solution was dried on the sample substrate, and the remaining matter was observed using a transmission electron microscope (TEM), the results of which are shown in Figure 2. As shown in Figure 2, it was found that the transparent solution contained clusters with a diameter of about 200 nm composed of semiconductor fine particles with a diameter of about 15 to 20 nm.

[0069] The obtained transparent solution was irradiated with a KrF excimer laser and photoluminescence evaluation by KrF excimer laser excitation was performed. As a result, blue light emission was confirmed from the transparent solution as shown in Figure 3. The fluorescence spectrum of the transparent solution was measured with and without KrF excimer laser irradiation using a SHIMADZU RF-5300PC fluorescence spectrophotometer. The results are shown in Figure 4. As shown in Figure 4, the transparent solution exhibited a fluorescence spectrum with a peak wavelength at 427 nm (excitation wavelength 250 nm). The solution irradiated with the KrF excimer laser (Figure 4(b)) had a much stronger emission intensity than the solution not irradiated with the KrF excimer laser (Figure 4(a)). Furthermore, this transparent solution exhibited absorption and emission for more than 100 hours.

[0070] Example 2 A semiconductor particle light-emitting device was fabricated on a glass substrate coated with a 150 nm thick ITO (transparent conductive film). First, a 70 nm thick poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) film and a 50 nm thick poly(9-vinylcarbazole) (PVK) film were formed on the ITO film by spin coating. Next, the transparent solution prepared in Example 2 was adjusted in concentration and spin-coated on the PVK film at 3,000 RPM for 1 minute to obtain a thin film with a thickness of about 300 nm. Furthermore, a 25 nm thick 3,3',5,5'-tetra[(m-pyridyl)-phen-3-yl]biphenyl (BP4mPy), a 1 nm thick lithium fluoride (LiF), and a 100 nm thick aluminum (Al) film were fabricated by vacuum deposition. The layer structure of the obtained light-emitting device is shown in FIG. 5.

[0071] When a voltage was applied to the obtained light-emitting device and a current was injected, the voltage-current characteristics and voltage-luminance characteristics were obtained (Figure 6). As shown in Figure 7, it was confirmed that this light-emitting device emits blue light with a peak at about 460 nm. The basic characteristics are shown in Figure 8. [Industrial Applicability]

[0072] INDUSTRIAL APPLICABILITY The present invention has industrial applicability as a raw material for organic light-emitting diodes (OLEDs) that can be used in organic EL display devices, in particular blue-emitting OLEDs, or as a material for solar cell devices that can be produced by a coating process. [Explanation of symbols]

[0073] 1...cathode, 2...anode, 3...active layer

Claims

1. A dispersion step of obtaining a dispersion liquid in which a powder containing gallium, a nitrogen source, and a powder containing indium or a powder containing aluminum are dispersed in an organic solvent; The method includes irradiating the dispersion with light to obtain semiconductor particles containing a semiconductor including gallium, nitrogen, and indium or aluminum. A method for producing semiconductor particles.

2. In the irradiation step, irradiating the powder in the dispersion with laser light to obtain the semiconductor particles; The method for producing semiconductor particles according to claim 1 .

3. In the irradiation step, irradiating the powder in the dispersion with single wavelength light or multiple wavelength light, either individually or alternately, to obtain the semiconductor particles. The method for producing semiconductor particles according to claim 1 or 2.

4. The dispersion contains dissolved nitrogen. The method for producing semiconductor particles according to any one of claims 1 to 3.

5. The dispersion liquid comprises polar molecules. The method for producing semiconductor particles according to any one of claims 1 to 4.

6. The dispersion liquid contains an amino group-containing compound. The method for producing semiconductor particles according to any one of claims 1 to 5.

7. A step of flowing a gas containing nitrogen into the dispersion liquid. The method for producing semiconductor particles according to any one of claims 1 to 6.

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