KR101057270B1 - Group 13 nitride semiconductor particle phosphor and its manufacturing method - Google Patents

Abstract

In the semiconductor particle fluorescent substance of the conventional invention, dispersibility in a medium is bad, and red, green, and blue fluorescence is not exhibited, and it cannot mix and obtain white light emission. In addition, this manufacturing method is complicated in the synthesis process, and in particular, the control of the composition and particle size of the semiconductor particles requires precise control of the synthesis method. Accordingly, the nanocrystalline particles 11 are formed as a semiconductor particle containing a bond between a Group 13 element and a nitrogen atom, and the nanocrystalline particles in the surface-modified organic compound 12 having a molecular weight of 200 to 500 containing a hetero atom. The dispersibility Group 13 nitride semiconductor particle phosphor 10 formed by covering (11) is provided. Furthermore, the simple manufacturing method of the said group 13 nitride semiconductor particle fluorescent substance 10 is provided.

Group 13 nitride semiconductor particle phosphor, exciton bore radius, luminescence intensity, nanocrystal particle

Description

Group 13 nitride semiconductor particle phosphor and its manufacturing method {GROUP 13 NITRIDE SEMICONDUCTOR PARTICLE PHOSPHOR AND METHOD FOR MANUFACTURING SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor particle phosphor and a method for producing the same, and specifically, to a group 13 nitride semiconductor particle phosphor having improved luminous intensity and luminous efficiency, and a group 13 nitride semiconductor particle phosphor having a simple synthesis procedure and high synthesis yield. It is about a method.

When semiconductor nanocrystal particles (hereinafter referred to as " nano crystal particles ") are excited to a small bore radius, it is known to exhibit a quantum size effect. The quantum size effect means that as the size of the material becomes smaller, the electrons therein cannot freely move, and in this state, the energy of the electrons can only be obtained at a specific value, not arbitrary. For example, the wavelength of light generated from nanocrystalline particles having a radius of exciton bore becomes shorter as the dimension becomes smaller.

However, surface defects occur because the surface of the nanocrystalline particles exhibiting such effects is dominated by dangling bonds. Therefore, a technique of capping the surface defects of nanocrystalline particles by covering the nanocrystalline particles with a semiconductor material having an energy gap larger than the energy gap has been proposed (Non-Watt et al. 1 (Yun Wei Cao and Uri Banin et al. Growth and Properties of Semiconductor Core / Shell Nanocrystals with InAs Cores "Journal of American Chemical Society 2000, 122, 9692-9702). Specifically, it is proposed to take a semiconductor core / protective semiconductor shell structure using nanocrystalline particles containing InAs as a semiconductor core and GaAs, InP, and CdSe as protective semiconductor shells.

Moreover, in order to improve water resistance, optical characteristics, etc., the synthesis | combination of the semiconductor ultrafine particle which couple | bonded the amino group via the linking organic residue is tried (refer patent document 1 (Unexamined-Japanese-Patent No. 2002-38145)).

Patent Document 1: Japanese Patent Laid-Open No. 2002-38145

[Non-Patent Document 1] Published by American Chemical Society, Yun Wei Cao and Uri Banin ("Growth and Properties of Semiconductor Core / Shell Nanocrystals with InAs Cores" Journal of American Chemical Society 2000, 122, 9692-9702)

<Start of invention>

Problems to be Solved by the Invention

The semiconductor core covered with the various protective semiconductor shells described in Non Patent Literature 1 mainly has a light emission wavelength in the near infrared region. Therefore, this semiconductor core is excited by a light emitting element of a GaN semiconductor as an excitation light source and cannot exhibit red, green, and blue fluorescence, and cannot mix and obtain white light emission.

In addition, since the semiconductor ultrafine particles described in Patent Document 1 bind the linking organic moiety to the nanocrystalline particles, the bonding strength is weak, which is not sufficient to completely protect the nanocrystalline particles and to improve the surface defects. In addition, the linking organic residue is linear, has a weak ability to disperse the nanocrystalline particles, aggregates, and decreases efficiency due to defects at the interface of the nanocrystalline particles. In addition, it is impossible to control the particle size of the nanocrystalline particles by the linking organic residue.

In view of the above situation, the present invention provides a Group 13 nitride semiconductor particle phosphor which is organically bonded firmly, has high dispersibility, high luminous efficiency, and high reliability by capping surface defects of nanocrystalline particles, and a simple manufacturing method thereof. The purpose is to provide.

Means for solving the problem

The present invention relates to a Group 13 nitride semiconductor particle phosphor formed by coating a nanocrystalline particle including a bond between a Group 13 element and a nitrogen atom with a surface-modified organic compound having a molecular weight of 200 to 500.

Here, it is preferable that a surface modified organic compound is an amine, especially tertiary amine. It is preferable that the nitrogen atom of a surface modified organic compound coordinates with the group 13 element of a nanocrystal particle. Moreover, it is preferable that a surface modified organic compound contains 2 or more types of compounds.

In addition, in the present invention, the Group 13 element of the nanocrystalline particles may be composed of two or more elements.

In the present invention, it is preferable that the particle diameter of the nanocrystalline particles is not more than twice the radius of the excitation bore.

In addition, the present invention is a method for producing a Group 13 nitride semiconductor particle phosphor formed by coating a nanocrystalline particle containing a bond between a Group 13 element and a nitrogen atom with a surface-modified organic compound, wherein at least the Group 13 element and nitrogen are bonded to each other. Provided is a method for producing a Group 13 nitride semiconductor particle phosphor which controls the particle size of nanocrystalline particles by a step of heating a synthetic solution containing a compound having and a surface-modified organic compound having a molecular weight of 200 to 500, including a hetero atom. . Here, 2 or more types of surface modified organic compounds can be used.

Moreover, the compound containing the bond of group 13 element and nitrogen atom is preferably an In compound and / or Ga compound.

The present invention can use a hydrocarbon system as the solvent of the synthesis solution.

Moreover, in this invention, the temperature which heats a synthesis solution becomes like this. Preferably it is 180-500 degreeC. In addition, the synthesis time for heating the synthesis solution is preferably 6 to 72 hours.

Effect of the Invention

Provided is a wide-gap Group 13 nitride semiconductor particle phosphor containing nanocrystalline particles and a surface-modified organic compound. In the group 13 nitride semiconductor particle phosphor of the present invention, the surface-modified organic compound containing a hetero atom and having a molecular weight of 200 to 500 is firmly bonded to the surface of the nanocrystalline particles, and protects the surface defects of the nanocrystalline particles. In addition, the nanocrystal particles are separated from each other by the organic molecular layer, and the nanocrystal particles do not aggregate with each other, and the dispersibility is good, and handling is easy when the phosphor is applied. In addition, since the surface of the nanocrystalline particles is firmly protected by the surface-modified organic compound, it is resistant to deterioration due to the excitation light source, and consequently, the luminescence intensity of the group 13 nitride semiconductor particle phosphor is improved.

Moreover, according to the manufacturing method of the group 13 nitride semiconductor particle fluorescent substance of this invention, the particle diameter of a nanocrystal particle can be controlled by making it react in a synthetic solvent and selecting surface-modified organic compound suitably. In addition, the surface-modified Group 13 nitride semiconductor particle phosphor, which has fewer processes than gas phase synthesis and protects the surface of nanocrystal particles simultaneously with synthesis in liquid phase, has less surface defects and has good dispersibility, can be synthesized in one step. Mass synthesis is possible.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram of the group 13 nitride semiconductor particle fluorescent substance of this invention.

Fig. 2 is a graph showing the relationship between the luminescence intensity showing the luminescence properties of group 13 nitride semiconductor particle phosphors and the particle size of nanocrystal grains.

3 is a schematic view of a semiconductor particle phosphor synthesized in Comparative Example 1. FIG.

<Brief description of symbols for the main parts of the drawings>

10: group 13 nitride semiconductor particle phosphor,

11: nanocrystalline particles,

12: surface modified organic compound.

Best Mode for Carrying Out the Invention

<Group 13 nitride semiconductor particle phosphor>

Hereinafter, the structure of the group 13 nitride semiconductor particle fluorescent substance which concerns on this invention is demonstrated based on FIG. The group 13 nitride semiconductor particle phosphor 10 according to the present invention is a structure in which the nanocrystalline particles 11 are coated with the surface-modified organic compound 12. It is thought that both the chemical bond which the hetero atom of the surface modification organic compound 12 coordinates to this nanocrystal particle 10, and the bond by physical adsorption contribute to this coating | cover.

<< nanocrystal grain >>

The nanocrystalline particles of the present invention are nanocrystalline particles of a semiconductor, and are compounds containing a bond between at least one or more of Group 13 elements (B, Al, Ga, In, Tl) and nitrogen atoms. Particularly preferred as nanocrystalline particles are GaN, InN, AlN, InGaN, InAlN, GaAlN, InAlGaN.

The nanocrystal particles may contain unintended impurities, and at low concentrations, at least one of Group 2 elements (Be, Mg, Ca, Sr, Ba), Zn, or Si may be intentionally added as a dopant. The concentration range of the dopant is particularly preferably between 1 × 10 ¹⁶ atoms / cm ³ and 1 × 10 ²¹ atoms / cm ³ , and the dopants preferably used are Mg, Zn, and Si.

The nanocrystalline particles may be a single particle structure containing only the above-described composition or may be a semiconductor core / semiconductor shell structure contained by one or more semiconductor shells of different compositions.

When the nanocrystal particles have a semiconductor core / semiconductor shell structure, the semiconductor core is preferably a semiconductor having a smallest band gap, for example, InN. In addition, it is preferable that the bandgap of a semiconductor shell (it is a 1st shell and a 2nd shell from an inner side when a semiconductor shell is two or more laminated bodies) is larger than a semiconductor core. The semiconductor shell does not need to contain all of the cabinet cores of the semiconductor core, and may have a distribution in the coating thickness.

In the case where the nanocrystalline particles of the present invention have a semiconductor core / semiconductor shell structure, TEM observation is performed, and the grain size of the semiconductor core and the thickness of the semiconductor shell can be confirmed by checking the lattice shape by the observation image at high magnification.

The average particle diameter of the semiconductor core can be approximated to 5 to 6 nm, typically less than twice the spectral half-width as a result of X-ray diffraction measurement, which are fine particles twice the radius of the exciton bore, and the thickness of the semiconductor shell is 1 to 10 nm. Is adjusted to the range of. Here, when the thickness of the semiconductor shell is smaller than 1 nm, it is not preferable because the surface of the semiconductor core cannot be sufficiently covered and the effect of quantum light shielding is weakened. On the other hand, if it is larger than 10 nm, it becomes difficult to make the semiconductor shell uniform, resulting in increased defects and undesirable in terms of raw material cost.

In the present invention, in the case where the nanocrystalline particles have a semiconductor core / semiconductor shell structure, the energy of semiconductor excitation light is absorbed by the semiconductor shell of the outer layer, and then transitions to the surrounding semiconductor core by the semiconductor shell. Here, since the particle diameter of the semiconductor core is small enough to have a quantum size effect, the semiconductor core can obtain only a plurality of discretized energy levels, but may be one level. Light energy transferred to the semiconductor core changes between the base level of the conduction band and the base level of the valence band, and light of a wavelength corresponding to the energy emits light.

It is preferable that the band gap of the nanocrystalline particles (the semiconductor core when the nanocrystalline particles are a semiconductor core / semiconductor shell structure) is in the range of 1.8 to 2.8 eV, and when used as a red phosphor, 1.85 to 2.5 eV is used as a green phosphor. In the case of 2.3-2.5 eV, and when used as a blue fluorescent substance, the range of 2.65-2.8 eV is especially preferable. In addition, the color of the phosphor is determined by adjusting the ratio of mixed crystals of the Group 13 elements. Therefore, it is preferable that the group 13 element of a nanocrystal particle contains 2 or more types.

The particle diameter of the nanocrystalline particles is preferably in the range of 0.1 nm to 100 nm, particularly preferably in the range of 0.5 nm to 50 nm, and even more preferably in the range of 1 to 20 nm.

When the nanocrystal grain size (nano crystal grain is a semiconductor core / semiconductor shell structure, the diameter of the semiconductor core) is less than twice the radius of the excitation bore, the emission intensity is extremely improved. The bore radius represents the expansion of the existence probability of the excitons and is represented by the following equation. For example, the exciton bore radius of GaN is about 3 nm, and the exciton bore radius of InN is about 7 nm.

y = 4πεh ² · me ²

here

y: bore radius,

ε: permittivity,

h: Frank's constant,

m: effective mass,

e: small amount of charge

to be.

In the case where the nanocrystalline particles are used as phosphors, when the particle diameter of the nanocrystalline particles becomes less than twice the radius of the excitation bore, the optical bandgap is widened due to the quantum size effect. .

<< surface modified organic compound >>

The surface modified organic compound of the present invention is defined as a compound having a hydrophilic group and a hydrophobic group in a molecule. Here, the hydrophobic group preferably comprises an aliphatic compound containing a nonpolar hydrocarbon and containing about 10 to 40 carbon atoms. Although the aliphatic compound is preferably a saturated fatty acid, an oxygen atom, a double bond, or an amide, an ester, or other functional group may be included. In addition, the hydrophobic group may be an aromatic hydrocarbon residue or an alicyclic compound. Examples of the hydrophilic group of the surface-modified organic compound include nitrogen-containing functional groups (nitro groups, amino groups, etc.), sulfur-containing functional groups (sulfo groups and the like), carboxyl groups, amide groups, phosphine groups, phosphine oxide groups, hydroxyl groups and the like.

Surface-modified organic compounds may contain other than hydrogen, oxygen, carbon in the molecule, the molecular weight is 200 to 500. Although it may have a hetero atom in either or both of a hydrophilic group and a hydrophobic group, it is preferable that at least a hydrophilic group has a hetero atom. At this time, the polarity is generated between the hetero atom and the hydrophobic group, thereby increasing the coordination force of the hetero atom of the hydrophilic group to the nanocrystalline particles. In addition, by coordinating hetero atoms, particularly nitrogen atoms, contained in the surface-modified organic compound with Group 13 elements of the nanocrystalline particles, defects due to unbonded loss of Group 13 elements on the surface of the nanocrystalline particles can be capped, and at the same time, nanocrystals It is thought that the aggregation of the particles can be prevented. In addition, it is considered that hydrophobic groups of surface-modified organic compounds are bonded to nanocrystalline particles by intermolecular forces by van der Waals forces, ionic bonds, hydrogen bonds, and the like. However, this intermolecular force is considered to be weaker than the coordination bond mentioned above. As described above, an organic molecular layer containing a surface-modified organic compound covering the nanocrystalline particles is generated.

The molecular weight of the surface modified organic compound of this invention fluctuates mainly by the molecular weight of a hydrophobic group. When the molecular weight is less than 200, the hydrophobic group becomes a surface-modified organic compound having a short aliphatic chain or a small molecular weight aromatic, and the force for protecting the nanocrystalline particles tends to be weakened. In addition, when the molecular weight exceeds 500, hydrophobic groups become long fatty chains or aromatics having large molecular weights, so that the intermolecular forces between the hydrophobic chains become strong due to van der Waals forces, ionic bonds, hydrogen bonds, and the like. Surface-modified organic compounds tend to bind strongly and weakly aggregate the nanocrystalline particles.

That is, when the molecular weight of the group 13 nitride semiconductor particle phosphor is 200 to 500, the surface-modified organic compound is firmly bonded to the surface of the nanocrystal particles, the surface defects of the nanocrystal particles are protected, and the organic molecules described above with each other among the nanocrystal particles. Can be separated into layers. As a result, the group 13 nitride semiconductor particle phosphor is dispersed and does not aggregate. And since it is easy to handle and the group 13 nitride semiconductor particle fluorescent substance is firmly protecting the surface, it is strong to deterioration by an excitation light source, and can improve the light emission intensity as a fluorescent substance.

It is preferable that a surface modified organic compound is an amine which is a compound which has a nonpolar hydrocarbon terminal as a hydrophobic group, and an amino group as a hydrophilic group. This is because electrical polarity between nitrogen-carbon atoms is generated between nitrogen, which is a hetero atom, and a hydrophobic group, for example, an aliphatic compound, and it is thought that the surface-modified organic compound is firmly attached to the surface of the nanocrystalline particles. In addition, since the nitrogen atom has three bonds, it is possible to select a surface-modified organic compound having 1 to 3 hydrophobic chains. The surface modified organic compound is preferably an aliphatic amine, but may also contain an aromatic amine.

In the present invention, the surface-modified organic compound is particularly preferably a tertiary amine. This is because it has three hydrophobic ends, so that the nanocrystalline particles coated with the surface-modified organic compound can be dispersed well.

In the case where all of the hydrophobic chains of the tertiary amines are aliphatic, the lengths (molecular weights) of all the hydrophobic chains are preferably equivalent. That is, the structure like the branch of the ratio which matched the tip with a nitrogen atom as an axis is preferable. This is because of protecting nanocrystalline particles at regular intervals. Further, it is preferable that one hydrophobic chain of the tertiary amine is a linear saturated fatty acid having 5 to 11 carbon atoms.

Examples of preferred tertiary amines include tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, triundecylamine and the like.

In addition, the surface-modified organic compound of the present invention is preferably a mixture of two or more kinds of compounds. This is because it is expected that the nanocrystalline particles can be firmly protected, which is impossible with one kind of surface-modified organic compound.

The thickness of the organic molecular layer of this invention can be confirmed by the observation image of TEM observation in high magnification. The organic molecular layer is preferably in the range of 0.1 to 50 nm, particularly preferably in the range of 0.5 to 20 nm, still more preferably in the range of 1 to 10 mn.

<Method for Producing Group 13 Elemental Compound>

In the present invention, the Group 13 element compound is a precursor of nanocrystalline particles, and is a compound containing a bond between a Group 13 element and a nitrogen atom. Hereinafter, the manufacturing method of the precursor of a nanocrystal particle using the In compound which has the bond of the said group 13 element compound and the nitrogen atom in the molecule, and the Ga compound which has the bond of a gallium atom and a nitrogen atom is demonstrated as an example. . Tris (dimethylamino) indium dimer, tris (dimethylamino) gallium dimer, and hexa (dimethylamino) indium gallium can be synthesize | combined by following Chemical Reaction Formulas 1-3.

Lithium dimethylamide and indium trichloride are reacted at a reaction temperature of 5 to 30 ° C., more preferably 10 to 25 ° C., for 24 to 120 hours, more preferably for 48 to 72 hours with stirring in a solvent of n-hexane. After the reaction is completed, lithium chloride as a by-product is removed, and tris (dimethylamino) indium dimer is taken out. This reaction is represented by the formula (1).

In the same manner, tris (dimethylamino) gallium dimer is synthesized while stirring lithium dimethylamide and gallium trichloride in an n-hexane solvent. This reaction is represented by the formula (2).

Subsequently, while stirring the tris (dimethylamino) indium dimer and tris (dimethylamino) gallium dimer synthesize | combined by the above-mentioned method in n-hexane solvent, at the synthesis temperature of 5-30 degreeC, More preferably, it is 10-25 degreeC. The reaction is carried out for 24 to 120 hours, more preferably 48 to 72 hours, and hexa (dimethylamino) indium gallium is taken out. This reaction is represented by the formula (3).

Since lithium dimethylamide, the tris (dimethylamino) indium dimer, tris (dimethylamino) gallium dimer, and hexa (dimethylamino) indium gallium of a product are highly reactive, it is preferable to carry out all in inert gas atmosphere.

<Method for producing group 13 nitride semiconductor particle phosphor>

<< when nanocrystal grain is single grain structure >>

A solution of benzene containing hexa (dimethylamino) indium gallium and tris (dimethylamino) gallium dimer in an arbitrary ratio as a precursor of nanocrystalline particles, in an amount of 0.1 to 10% by mass, and 1 to 50% by mass of a surface-modified organic compound. Is dissolved (growth of group 13 nitride semiconductor particle phosphor), and the mixed synthetic solution is sufficiently stirred, followed by reaction.

The reaction is carried out in an inert gas atmosphere, and heating is carried out while stirring the synthesis solution at a synthesis temperature of 180 to 500 ° C, more preferably 280 to 400 ° C, for 6 to 72 hours, more preferably 12 to 48 hours. To complete. Subsequently, washing is performed several times with n-hexane and methanol anhydride to remove organic impurities. In addition, the reaction proceeds simultaneously with the formation of the indium nitride gallium mixed crystal nanocrystal particles and the formation of the group 13 nitride semiconductor particle phosphor formed by coating the same with a surface-modified organic compound. Thereby, the group 13 nitride semiconductor particle fluorescent substance containing the indium nitride gallium mixed crystal coated with the surface modification organic compound can be obtained.

At this time, if the molecular weight of the surface-modified organic compound in the synthesis solution is increased, the indium nitride / gallium mixed crystal nanocrystal particles can be made smaller. On the contrary, if the molecular weight of the surface-modified organic compound is decreased, the indium nitride / gallium mixed crystal nanocrystal particles can be made larger. Can be. It is thought that this originates in what surface-modified organic compound also has a function as surfactant. That is, as the molecular weight of the surface-modified organic compound increases, the length and three-dimensional volume of the hydrophobic group increases, and the surface-modified organic compound tends to be condensed, whereby it is thought that the nanocrystal particles become smaller in the manufacturing process. As described above, by using the surface-modified organic compound having a molecular weight of 200 to 500 as described above in the method for producing a group 13 nitride semiconductor particle phosphor, the particle diameter of the nanocrystalline particles can be controlled to several nm to several tens of nm.

The present invention dissolves a Group 13 element compound in a hydrocarbon solvent containing a surface-modified organic compound, heats the mixed solution, reacts in one step, and is coated with the surface-modified organic compound through an optional cooling recovery process. A group nitride semiconductor particle phosphor is produced.

In addition, in this invention, a surface modification organic compound and its raw material are the same as a chemical substance. Therefore, it is preferable that it is an amine which is a compound which has a nonpolar hydrocarbon terminal as a hydrophobic group and an amino group as a hydrophilic group as a surface modified organic compound used at a manufacturing process. It is also particularly preferred that it is a tertiary amine for particle size control. This is because the tertiary amine can select the length and three-dimensional volume of various hydrophobic groups, and it is easy to control the size of the nanocrystalline particles. Specific examples of the tertiary amine include tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, triundecylamine and the like.

In addition, in this invention, it is preferable that two or more types of surface modification organic compounds are used at a manufacturing process. The particle size of the nanocrystalline particles is determined by mixing two or more kinds of surface-modified organic compounds having different molecular weights and using them in combination, for example, by using the particle diameters of the nanocrystalline particles determined according to the size of the molecular weight of the surface modified organic compound to be used. This can be controlled and controlled. Moreover, the particle diameter of a nanocrystal particle can be controlled by the ratio of mixing of surface modified organic compounds from which molecular weight differs. For example, the particle diameter of nanocrystal grain | particles becomes small, so that the ratio which mixes the surface modified organic compound with larger molecular weight is made higher.

In addition, in this invention, the compound solution containing only a carbon atom and a hydrogen atom is called a hydrocarbon solvent. Examples of hydrocarbon solvents include n-pentane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane, cycloheptane, benzene, toluene, o-xylene, m-xylene, p-xylene and the like. .

<< when nanocrystal particle is a semiconductor core / semiconductor shell structure >>

The hexa (dimethylamino) indium gallium and tris (dimethylamino) gallium dimers are arbitrarily proportioned to the Group 13 nitride semiconductor particle phosphor in which the nanocrystalline particles dissolved in the hydrocarbon solvent prepared by the above-described method have a single particle structure. Combined and mixed 0.1-10 mass%. In addition, 1-50 mass% of surface modified organic compounds are mixed at the same time, reaction is performed, after fully preparing the prepared synthetic solution.

This reaction is carried out in an inert gas atmosphere and is heated with stirring the synthesis solution at a synthesis temperature of 180 to 500 ° C, more preferably 280 to 400 ° C for 6 to 72 hours, more preferably 12 to 48 hours. In order to remove an organic impurity after reaction, it wash | cleans several times with n-hexane and methanol anhydride.

By this reaction, the semiconductor shell is made of the hexa (dimethylamino) indium gallium and tris (dimethylamino) gallium dimer added as a material by using the nanocrystal particles which are the single particle structure of the group 13 nitride semiconductor particle phosphor as a semiconductor core. This grows and a semiconductor core / semiconductor shell structure is formed.

In addition, the reaction proceeds simultaneously with the formation of the indium nitride gallium mixed crystal semiconductor core / semiconductor shell structure nanocrystal particles and the formation of a group 13 nitride semiconductor particle phosphor formed by coating the surface-modified organic compound.

Moreover, it is also possible to make several layers of a semiconductor shell by repeating this operation.

Thereby, the group 13 nitride semiconductor particle fluorescent substance in which the nanocrystal particle of the semiconductor core / semiconductor shell structure coat | covered with the surface modification organic compound contains the indium gallium gallium mixed crystal can be obtained.

(Example 1)

It synthesize | combined by the following method so that the particle diameter of group 13 nitride nanocrystal particle might be set to 4 nm by using two surface-modified organic compounds.

First, hexa (dimethylamino) indium gallium was synthesize | combined by the reaction shown to the said General formulas 1-3.

In addition, since lithium dimethylamide and the tris (dimethylamino) indium dimer, tris (dimethylamino) gallium dimer, and hexa (dimethylamino) indium gallium of the product are highly reactive, all of the reactions shown below are in a nitrogen gas atmosphere. It was done.

First, 0.03 mol of lithium dimethylamide and 0.01 mol of indium trichloride were weighed in a glove box, and the reaction was carried out at 20 ° C. for 50 hours while stirring them in n-hexane. After the reaction was completed, lithium chloride as a byproduct was removed, and tris (dimethylamino) indium dimer was taken out (Formula 1).

Tris (dimethylamino) gallium dimer was synthesized by the same method (Formula 2). In addition, 0.005 mol of tris (dimethylamino) indium dimer and 0.005mol of tris (dimethylamino) gallium dimer synthesized by the above-described method were weighed, and these were stirred in n-hexane for 50 hours at a heating temperature of 20 ° C. The reaction was carried out. Thereafter, hexa (dimethylamino) indium gallium was taken out (formula 3).

Subsequently, 0.02 mol of hexa (dimethylamino) indium gallium and 0.03 mol of tris (dimethylamino) gallium dimer were added to 25 g of trinonylamine (molecular weight: 395.75) and 5 g of trioctylamine (molecular weight: 353.67) as surface-modified organic compounds. The mixture was dissolved in a solution containing 200 ml of benzene as a solvent and a mixture, and the mixed solution was sufficiently stirred, followed by reaction (Formula 4).

By this reaction, the formation of the indium gallium mixed crystal nanocrystal particles and the formation of the group 13 nitride semiconductor particle phosphor formed by coating the surface with a surface-modified organic compound proceed simultaneously. In _0.2 Ga _0.8 N / nN (C ₉ H ₁₉ ) ₃ , nN (C ₈ H ₁₇ ) ₃ (in _0.2 Ga _0.8 N coated with two surface-modified organic compounds of nN (C ₉ H ₁₉ ) ₃ and nN (C ₈ H ₁₇ ) ₃ Nano crystal particle structure).

This reaction was carried out in a nitrogen gas atmosphere and completed by heating at 320 ° C. for 12 hours. During the heating, the synthesis solution was continuously stirred with a stirrer. Subsequently, washing was performed three times with n-hexane and methanol anhydride to remove organic impurities.

The nanocrystal particles of the group 13 nitride semiconductor particle phosphor obtained in this example are indium gallium nitride mixed crystals, and the nanocrystal particles are not aggregated and uniform size is obtained by uniformly covering the surface with two surface-modified organic compounds. The dispersibility was high.

In addition, in this Group 13 nitride semiconductor particle phosphor, a blue light emitting element containing a Group 13 nitride can be used as the excitation light source, and in particular, the emission of 405 mn of high external quantum efficiency can be efficiently absorbed. In addition, the nanocrystalline particles containing In _0.2 Ga _0.8 N could exhibit blue emission because the In composition ratio was adjusted so that the emission wavelength was 460 nm. In addition, the particle size is controlled by two kinds of surface-modified organic compounds, and as a result of X-ray diffraction measurement of the obtained Group 13 nitride semiconductor particle phosphor, the average particle diameter (diameter) of the nanocrystal particles estimated from the spectral half width is Scherrer. Using Equation 2, Equation 2 can be approximated to 4 nm, and the nanocrystalline particles show quantum size effects and the luminous efficiency is improved. In addition, the yield of the group 13 nitride semiconductor particle fluorescent substance obtained in this Example was 95%.

B = λ / CosΘR

here

B: X-ray half width [deg],

λ: wavelength of the X-rays [nm],

Θ: Bragg angle [deg],

R: particle diameter [mm]

.

(Example 2)

A nanocrystal particle is a method of synthesizing a group 13 nitride semiconductor particle phosphor having an indium nitride gallium mixed crystal and having a particle diameter of 5 nm, except that 30 g of trioctylamine is used as the surface-modified organic compound. The blue group 13 nitride semiconductor particle fluorescent substance was obtained by the manufacturing method similar to the 1st. The obtained Group 13 nitride semiconductor particle fluorescent substance was able to absorb especially 405 nm light emission with high external quantum efficiency especially. Further, the nanocrystalline particles had a light emission wavelength of 475 nm.

As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the nanocrystal particles estimated from the spectral half width can be approximated to 5 nm using the Scherrer equation, and the emission peak intensity is lower than that of the conventional indium nitride semiconductor particle phosphor. It is about 5 times better. In the production method of this embodiment, by using trioctylamine as the surface-modified organic compound, the force of condensing the precursor of the nanocrystal grains becomes weaker than the mixture of trinonylamine and trioctylamine, and the indium nitride gallium mixed crystal nanocrystal It was thought that the particles became large.

(Example 3)

A nanocrystal particle is a method of synthesizing a group 13 nitride semiconductor particle phosphor having an indium nitride gallium mixed crystal and having a particle diameter of 2 nm, except that 30 g of trinonylamine is used as the surface-modified organic compound. The blue group 13 nitride semiconductor particle fluorescent substance was obtained by the manufacturing method similar to the 1st. The obtained Group 13 nitride semiconductor particle fluorescent substance was able to efficiently absorb the light emission of 405mn which is especially high in external quantum efficiency. In addition, the nanocrystal particles had an emission wavelength of 455 nm.

As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the nanocrystal particles estimated from the spectral half width can be estimated to 2 nm using Scherer's equation, and the nanocrystal particles exhibit a quantum size effect and the luminous efficiency is improved. Improved. In the production method of the present embodiment, by using trinonylamine as the surface-modified organic compound, the force of aggregating the precursor of the nanocrystal grains becomes stronger than the mixture of trinonyl amine and trioctylamine, and indium nitride gallium mixed crystal nano It was thought that crystal grains became small.

(Example 4)

A nanocrystal particle is a method of synthesizing a group 13 nitride semiconductor particle phosphor having an indium nitride gallium mixed crystal and having a particle diameter of 15 nm, and is a surface-modified organic compound, 5 g of trioctylamine and trihexylamine (molecular weight: 269.51) A blue group 13 nitride semiconductor particle phosphor was obtained by the same production method as in Example 1 except that a mixture with 25 g was used. The obtained Group 13 nitride semiconductor particle fluorescent substance was able to absorb especially 405 nm light emission with high external quantum efficiency especially. Further, the nanocrystalline particles had a light emission wavelength of 475 nm.

As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the nanocrystal particles estimated from the spectral half width can be estimated to 15 nm using the Scherrer equation, and the emission peak intensity is lower than that of the conventional indium nitride semiconductor particle phosphor. It is about 5 times better. In the production method of the present embodiment, by using a mixture of trioctylamine and trihexylamine having a low molecular weight as the surface-modified organic compound, the force of condensing the precursor of the nanocrystalline particles rather than the mixture of trinonylamine and trioctylamine It was thought that this weakened and the indium nitride gallium mixed crystal nanocrystal particles became large.

(Example 5)

A method of synthesizing a Group 13 nitride semiconductor particle phosphor in which the nanocrystalline particles are indium nitride and the particle size of the nanocrystalline particles is 4 nm, and tris (dimethylamino) indium dimer 0.1 as a Group 13 element compound that is a precursor of the nanocrystalline particles. Except for using mole, the red group 13 nitride semiconductor particle fluorescent substance was obtained by the manufacturing method similar to Example 1. The obtained Group 13 nitride semiconductor particle fluorescent substance was able to absorb especially 405 nm light emission with high external quantum efficiency especially. Further, the nanocrystalline particles had a light emission wavelength of 610 nm.

As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the nanocrystal particles estimated from the spectral half width can be approximated to 4 nm using Scherer's equation, and the nanocrystal particles exhibit a quantum size effect, and the emission peak intensity Is improved by about 20 times compared with the conventional indium nitride semiconductor particle phosphor.

(Example 6)

0.1 mol of tris (dimethylamino) gallium dimer as a Group 13 element compound which is a method of synthesizing a Group 13 nitride semiconductor particle phosphor in which the nanocrystalline particles are gallium nitride and the particle size of the nanocrystalline particles is 4 nm. A group 13 nitride semiconductor particle fluorescent substance was obtained by the same manufacturing method as Example 1 except using this.

As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the nanocrystal particles estimated from the spectral half width can be approximated to 4 nm using Scherer's equation, and the nanocrystal particles exhibit a quantum size effect, and the emission peak intensity Is improved by about 20 times compared with the conventional gallium nitride semiconductor particle phosphor.

(Example 7)

It is a method of synthesizing green Group 13 nitride semiconductor particle phosphor (In _0.3 Ga _0.7 N / nN (C ₈ H ₁₇ ) ₃ ) in which the nanocrystalline particles are indium nitride gallium mixed crystal and the nanocrystalline particles have a particle diameter of 4 nm, As a Group 13 element compound that is a precursor of the nanocrystalline particles, 0.013 mol of hexa (dimethylamino) indium gallium and 0.02mol of tris (dimethylamino) gallium dimer are used, except that green 13 is used in the same manufacturing method as in Example 1. A group nitride semiconductor particle phosphor (In _0.3 Ga _0.7 N / nN (C ₉ H ₁₉ ) ₃ , nN (C ₈ H ₁₇ ) ₃ ) was obtained. The obtained Group 13 nitride semiconductor particle fluorescent substance was able to efficiently absorb the light emission of 405mn which is especially high in external quantum efficiency. In addition, the InN nanocrystalline particles had a light emission wavelength of 520 nm.

As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the nanocrystal particles estimated from the spectral half width can be approximated to 4 nm using Scherer's equation, and the nanocrystal particles exhibit a quantum size effect, and the emission peak intensity Was improved by about 20 times compared with the conventional indium gallium mixed crystal semiconductor particle phosphor.

(Example 8)

It is a method of synthesizing a red Group 13 nitride semiconductor particle phosphor (In _0.5 Ga _0.5 N / nN (C ₈ H ₁₇ ) ₃ ) having a nanocrystal grain of indium nitride and gallium mixed crystal and having a particle diameter of 4 nm. Red group 13 nitride semiconductor particle fluorescent substance (In _0.5 Ga _0.5 N) by the same manufacturing method as Example 1 except using 0.1 mol of hexa (dimethylamino) indium gallium as a group 13 element compound which is a precursor of nanocrystal particle. / nN (C ₉ H ₁₉ ) ₃ , nN (C ₈ H ₁₇ ) ₃ ) was obtained. The obtained Group 13 nitride semiconductor particle fluorescent substance was able to absorb especially 405 nm light emission with high external quantum efficiency especially. Further, the nanocrystalline particles had a light emission wavelength of 600 nm.

As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the nanocrystal particles estimated from the spectral half width can be approximated to 4 nm using Scherer's equation, and the nanocrystal particles exhibit a quantum size effect, and the emission peak intensity Was improved by about 20 times compared with the conventional indium gallium mixed crystal semiconductor particle phosphor.

(Comparative Example 1)

Trichloride, gallium (GaCl ₃₎ 0.007 mol, trichloroacetic indium (InCl ₃₎ 0.003 mole and mixed with lithium nitride (Li ₃ N) 0.01 mol in 100 ㎖ benzene ((C ₆ H _12), and the reaction solution was prepared. Synthesis Temperature Reaction was performed for 3 hours at 320 degreeC, and the semiconductor core as nanocrystal grains was synthesize | combined The reaction solution after synthesis was cooled to room temperature, and it was set as the benzene solution of the semiconductor core.

Then, with the semiconductor core benzene solution, trichloroacetic gallium (GaCl ₃₎ 0.009 mole of phosphorus trichloride indium (InCl ₃₎ 0.001 mole and a lithium nitride (Li ₃ N) 0.01 mol in a mixed to 100 ㎖ benzene, and the synthesis temperature of 350 ℃ The reaction was carried out for 24 hours, the semiconductor core was covered with a protective semiconductor shell, and the semiconductor particle fluorescent substance having a semiconductor core / protective semiconductor shell two-layer structure was synthesized.

The structural diagram of the group 13 nitride semiconductor particle fluorescent substance synthesize | combined by FIG. 3 in FIG.

The Group 13 nitride semiconductor particle phosphor obtained in Comparative Example 1 has a two-layer structure for the purpose of capping defects caused by unbonded damage, and since the surface-modified organic compound does not exist on the surface of the nanocrystalline particles, Nanocrystalline particles aggregate and have poor dispersibility. In addition, since the particle size control of the nanocrystalline particles depends only on the reaction temperature and the reaction time, it is difficult to control the particle size. In addition, since the group 13 element and the nitrogen atom do not have a bond between the precursors of the nanocrystalline particles, the blue light emitting element containing the group 13 nitride is used as the excitation light source, and the precise group 13 element is mixed to realize the desired emission wavelength. Composition control is difficult. As a result of the X-ray diffraction measurement of the obtained phosphor, the average particle diameter (diameter) of the core estimated from the spectral half width can be approximated to 50 nm using the Scherrer equation, and does not exhibit a quantum size effect. In addition, the yield of the group 13 nitride fluorescent substance obtained by this comparative example 1 was 50%.

FIG. 2 is a diagram showing the relationship between the luminescence intensity showing the luminescence properties of semiconductor particle phosphors and the particle size of nanocrystal particles. FIG. The horizontal axis represents the particle diameter (unit: nm) of the nanocrystal particles, and the vertical axis represents the arbitrary emission intensity "a.u. (arbitrary units)" when the phosphor emits light at 460 nm when excited with light of 405 nm. In the figure, (a) is the luminescence intensity in the group 13 nitride semiconductor particle phosphor of Example 1, and (b) in the figure shows the luminescence intensity in the group 13 nitride semiconductor particle phosphor of Comparative Example 1.

(C) in the figure is a curve showing the relationship between the luminescence intensity and the particle diameter of nanocrystals, and it was found that the luminescence intensity was extremely improved when the particle diameter of the nanocrystal particles was 2 times or less of the excitation bore radius. Also, as can be seen from FIG. 2, it was found that the nanocrystal particles according to Example 1 had a smaller exciton bore radius and higher fluorescence efficiency than those according to Comparative Example 1.

It should be thought that embodiment and the Example which were disclosed this time are an illustration and restrictive at no points. The scope of the invention is indicated by the claims rather than the foregoing description, and is intended to include the meaning of the claims and their equivalents and all modifications within the scope.

The present invention provides a Group 13 nitride semiconductor particle phosphor having a function excellent in dispersibility, medium affinity, and luminous efficiency, and a manufacturing method having high yield.

Claims (15)

Group 13 nitride semiconductor particles comprising a nanocrystalline particle 11 containing a bond between a group 13 element and a nitrogen atom, coated with a surface-modified organic compound 12 having a molecular weight of 200 to 500. Phosphor (10). The group 13 nitride semiconductor particle phosphor (10) according to claim 1, wherein the surface modified organic compound (12) is an amine. The group 13 nitride semiconductor particle phosphor (10) according to claim 2, wherein the surface modified organic compound (12) is a tertiary amine. The Group 13 nitride semiconductor particle phosphor (10) according to claim 2, wherein the nitrogen atom of the surface-modified organic compound (12) is coordinated with the Group 13 element of the nanocrystal particle (11). The group 13 nitride semiconductor particle phosphor (10) according to claim 1, wherein the surface modified organic compound (12) contains two or more kinds of compounds. The Group 13 nitride semiconductor particle phosphor (10) according to claim 1, wherein the Group 13 element of the nanocrystalline particles (11) contains two or more elements. The group 13 nitride semiconductor particle phosphor (10) according to claim 1, wherein the particle diameter of the nanocrystalline particles (11) is not more than twice the radius of the exciton bohr. A method for producing a group 13 nitride semiconductor particle phosphor (10) formed by coating a nanocrystalline particle (11) containing a bond between a group 13 element and a nitrogen atom with a surface-modified organic compound (12), wherein the group 13 element and nitrogen The particle diameter of the nanocrystal particles 11 was heated by a step of heating a synthetic solution containing a group 13 element compound having a bond with and a hetero atom and a surface-modified organic compound 12 having a molecular weight of 200 to 500. The manufacturing method of group 13 nitride semiconductor particle fluorescent substance (10) characterized by controlling. The method for producing a group 13 nitride semiconductor particle phosphor (10) according to claim 8, wherein two or more kinds of surface-modified organic compounds (12) are used. 9. The Group 13 nitride semiconductor particle phosphor 10 according to claim 8, wherein the Group 13 elemental compound comprising a bond between the Group 13 element and the nitrogen atom is an In compound, a Ga compound, or a compound of In and Ga. Way. The method for producing a group 13 nitride semiconductor particle phosphor (10) according to claim 8, wherein a hydrocarbon type is used as a solvent of the synthesis solution. The method for producing a group 13 nitride semiconductor particle phosphor (10) according to claim 8, wherein the temperature for heating the synthesis solution is 180 to 500 ° C. The method for producing a group 13 nitride semiconductor particle phosphor (10) according to claim 8, wherein a synthesis time for heating the synthesis solution is 6 to 72 hours. The group 13 nitride according to claim 1, wherein the surface-modified organic compound (12) is at least one of trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, and triundecylamine. Semiconductor particle phosphor 10. The group 13 nitride according to claim 8, wherein the surface-modified organic compound (12) is at least one of trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, and triundecylamine. The manufacturing method of the semiconductor particle fluorescent substance 10.

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