JP4761357B2 - Semiconductor particle phosphor and method for producing the same - Google Patents

Description

  The present invention relates to a semiconductor particle phosphor and a method for producing the same, and more particularly, a semiconductor particle phosphor having improved emission intensity and luminous efficiency, and a semiconductor particle phosphor having a simple synthesis procedure and a high synthesis yield. Regarding the method.

  It has been found that when semiconductor crystal particles (hereinafter referred to as “crystal particles”) are made as small as an exciton Bohr radius, a quantum size effect is exhibited. The quantum size effect is that when the size of a material is reduced, the electrons in it cannot move freely. In such a state, the energy of the electrons is not arbitrary and can take only a specific value. For example, the wavelength of light generated from crystal particles having an exciton Bohr radius is shorter as the size is smaller.

  However, since the surface of crystal grains where such effects appear is dominated by tangling bonds (unbonded hands), the crystal grains have a larger band gap than their band gap (referred to below as the energy gap between bands, the same shall apply hereinafter). A technique of capping crystal particle surface defects by covering with a material having a non-patent document (Non-Patent Document 1) has been proposed. Non-Patent Document 1 proposes a semiconductor core / semiconductor shell structure using InAs as a semiconductor core and GaAs, InP, and CdSe as a semiconductor shell.

Furthermore, attempts have been made to synthesize nitride semiconductor fine particles as wide gap crystal grains (Patent Document 1).
Japanese Patent Laid-Open No. 2002-220213 Yun Wei Cao and Uri Banin (Journal of American Chemical Society 2000, 122, 9629-9702) American Chemical Society Publishing

  The InAs core covered with various semiconductor shells described in Non-Patent Document 1 mainly has an emission wavelength in the near infrared region. Therefore, it cannot be excited by a GaN-based semiconductor light-emitting element as an excitation light source and cannot exhibit red, green, and blue fluorescence, and cannot emit white light by mixing these colors. The manufacturing method of the semiconductor core / semiconductor shell structure described in Non-Patent Document 1 employs a two-stage manufacturing method in which a semiconductor core is manufactured once and then a semiconductor shell is manufactured on the surface of the semiconductor core.

  In addition, the nitride-based semiconductor described in Patent Document 1 is not surface-modified, and the internal quantum efficiency (hereinafter referred to as light emission efficiency) at the time of light emission is reduced due to surface defects of crystal grains. Further, since the crystal particles are not surface-modified, they aggregate and the luminous efficiency is lowered due to defects at the crystal particle interface. Further, the method for controlling the particle size of crystal particles depends only on the reaction temperature and reaction time.

  In view of the above situation, an object of the present invention is to provide a semiconductor particle phosphor having high luminous efficiency and excellent reliability by capping surface defects of crystal grains, and a simple manufacturing method thereof.

  The present invention relates to a semiconductor particle phosphor characterized in that crystal particles containing a bond between a group 13 element and a nitrogen atom are coated with a modified organic compound containing at least a bond between a nitrogen atom and a carbon atom. In the present invention, it is desirable that the group 13 element of the crystal grain is composed of two or more elements. In the present invention, the nitrogen atom of the surface modification molecule is preferably coordinated to a group 13 element of the crystal particle. Desirably, the modified organic compound is an amine. In the present invention, it is desirable that the crystal grains have a particle size not more than twice the exciton Bohr radius.

  The present invention also relates to a method for producing a semiconductor particle phosphor obtained by coating crystal particles containing a bond between a group 13 element and a nitrogen atom with a modified organic compound containing at least a bond between a nitrogen atom and a carbon atom. The manufacturing method of a semiconductor particle fluorescent substance characterized by including the process of heating the synthetic solution which mixed the group 13 element compound and the said modified organic compound. In addition, the present invention is preferably a method for producing a semiconductor particle phosphor, wherein the group 13 element is In and / or Ga. In addition, the present invention is preferably a method for producing a semiconductor particle phosphor, wherein a hydrocarbon system is used as the synthetic solution solvent.

  In the present invention, it is desirable that a temperature for heating the synthetic solution is 180 to 500 ° C. In the present invention, it is desirable that the time for heating the synthesis solution is 6 to 72 hours.

  As a wide-gap semiconductor particle phosphor, by covering the crystal particle surface with a modified organic compound containing nitrogen and carbon atoms, it is possible to capping surface defects of the crystal particle, and to improve the emission intensity and emission efficiency. is there. The modified organic compound has an electric polarity between the nitrogen atom and the carbon atom due to the bond between the nitrogen atom and the carbon atom in the molecule, and can be firmly attached to the crystal particle surface.

  Further, when the crystal particles are made of a mixed crystal of a group 13 element, the emission wavelength can be controlled, and red, green, and blue light can be emitted, and these can be mixed to obtain white light emission.

  In addition, since the nitrogen atom contained in the modified organic compound is coordinated to the group 13 element of the crystal grain, defects due to dangling bonds of the group 13 element on the surface of the crystal grain can be capped.

  In addition, since the amine has an elemental nitrogen and an organic group that is a carbon chain, the nitrogen atom coordinates to the crystal particle, so that the organic group is directed to the outside of the semiconductor particle phosphor, thereby preventing aggregation of the crystal particle.

  Further, if the grain size of the crystal particles is not more than twice the Bohr radius, the quantum size effect becomes significant, and the luminous efficiency increases.

  According to the method for producing a phosphor of the present invention, by reacting in a synthesis solvent, the number of steps is less than that of gas phase synthesis, and a semiconductor particle phosphor can be synthesized in a single phase in a liquid phase. It becomes possible.

  In addition, since the group 13 element compound has a Ga—N—In bond, it is easy to control the composition ratio of the InGaN mixed crystal that is a crystal grain to be manufactured.

  In addition, by using a hydrocarbon-based solvent, there is little mixing of water and air in the synthesis solution, so there is no mixing of oxygen in the crystal particles. Further, since the synthesis temperature is 180 to 500 ° C., it can be synthesized at a lower temperature than the gas phase synthesis, and the operation is simple. Further, when the synthesis time is 6 to 72 hours, the crystal particles have sufficiently high crystallinity and few defects.

<Crystal particles>
The crystal grain of the present invention is a semiconductor grain, and is composed of a bond between a nitrogen atom and at least one of group 13 elements (B, Al, Ga, In, Tl). Particularly preferred are GaN, InN, AlN, InGaN, InAlN, GaAlN, and InAlGaN.

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

  The crystal grains may have a single particle structure composed of only the above composition or a semiconductor core / semiconductor shell structure encompassed by one or more semiconductor shells having different compositions.

  When the crystal grains have a semiconductor core / semiconductor shell structure, the semiconductor core is preferably a semiconductor having a composition with the smallest band gap, such as InN. Moreover, it is preferable that the band gap of the semiconductor shell (when the semiconductor shell is a laminated body of two or more is referred to as the first shell and the second shell from the inner shell side) is larger than that of the semiconductor core. The semiconductor shell does not have to include the entire inner core of the semiconductor core, and the coating thickness may be distributed.

  When the crystal particles of the present invention have a semiconductor core / semiconductor shell structure, the TEM observation is performed, and the lattice image is confirmed by the observation image at a high magnification to thereby determine the particle diameter of the semiconductor core and the thickness of the semiconductor shell. I can confirm.

  The average particle size of the semiconductor core of the present invention is usually estimated to be 5 to 6 nm from the half-value width of the spectrum as a result of X-ray diffraction measurement, and this is a fine particle having an exciton Bohr radius of twice or less, and the thickness of the semiconductor shell. The thickness is adjusted to a range of 1 to 10 nm. Here, if the thickness of the semiconductor shell is smaller than 1 nm, the surface of the semiconductor core cannot be sufficiently covered, and the effect of quantum confinement becomes weak, which is not preferable. On the other hand, when the thickness is larger than 10 nm, it is difficult to make a shell uniformly and defects are increased, which is undesirable in terms of raw material costs.

  In the present invention, when the crystal grains have a semiconductor core / semiconductor shell structure, the energy of the semiconductor excitation light is absorbed by the semiconductor shell of the outer layer and then transitions to the semiconductor core surrounded 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 take only a plurality of discretized energy levels, but may have one level. The light energy transitioned to the semiconductor core transitions between the ground level of the conduction band and the ground level of the valence band, and light having a wavelength corresponding to the energy is emitted.

  The band gap of the crystal particles (semiconductor core when the crystal particles are a semiconductor core / semiconductor shell structure) is preferably in the range of 1.8 to 2.8 eV, and 1.85 when used as a red phosphor. The range of ~ 2.5 eV, 2.3 to 2.5 eV when used as a green phosphor, and 2.65 to 2.8 eV when used as a blue phosphor are particularly preferred. The color of the phosphor is determined by adjusting the ratio of the mixed crystal of the group 13 metal.

  The particle size of the crystal particles is preferably in the range of 0.1 nm to 10 μm, particularly preferably in the range of 0.5 nm to 1 μm, and further preferably in the range of 1 to 20 nm.

  When the crystal particle diameter (or the semiconductor core diameter when the crystal particle is a semiconductor core / semiconductor shell structure) is not more than twice the exciton Bohr radius, the emission intensity is extremely improved. The Bohr radius indicates the spread of the existence probability of excitons and is expressed by Equation (1). For example, the exciton Bohr radius of GaN is about 3 nm, and the exciton Bohr radius of InN is about 7 nm.

Where y: Bohr radius,
ε: dielectric constant,
h: Planck's constant,
m: effective mass,
e: Elementary charge.

When crystal particles are used as the phosphor, the optical band gap widens due to the quantum size effect when the particle size is less than or equal to twice the exciton Bohr radius, but even in that case, it is preferably within the above-mentioned band gap range.
<Semiconductor particle phosphor>
Hereinafter, the structure of the semiconductor particle phosphor according to the present invention will be described with reference to FIG. The semiconductor particle phosphor 10 according to the present invention is formed by coating the crystal particles 11 with the modified organic compound 12. It is considered that both the chemical bond in which the nitrogen atom of the modified organic compound coordinates to the crystal particle and the bond by physical adsorption contribute to this coating.

Here, the modified organic compound is defined as a compound having a hydrophilic group and a hydrophobic group in the molecule.
Desirably, the modified organic compound is an amine which is a compound having a nonpolar hydrocarbon terminal as a hydrophobic group and an amino group as a hydrophilic group. Specific examples thereof include butylamine, t-butylamine, isobutylamine, tri-n-butylamine, triisobutylamine, triethylamine, diethylamine, hexylamine, dimethylamine, laurylamine, octylamine, tetradecylamine, and trioctylamine. is there.

  The modified organic compound 12 covers the wide-gap crystal particles 11 so that the surface defects of the crystal particles 11 are capped, and the light emission intensity and the light emission efficiency are improved. Further, it is considered that the modified organic compound 12 has an electric polarity between a nitrogen atom and a carbon atom and adheres firmly to the surface of the crystal particle 11.

Further, it is considered that defects due to dangling bonds of the group 13 element on the surface of the crystal particle 11 can be capped by the nitrogen atom contained in the modified organic compound 12 being coordinated to the group 13 element of the crystal particle 11.
<Method for producing group 13 element compound>
In the present invention, the group 13 element compound is a precursor of crystal particles. Hereinafter, a method for producing a precursor of crystal particles using a compound having a bond of indium atom and nitrogen atom and a bond of gallium atom and nitrogen atom in the molecule will be described as an example. Tris (dimethylamino) indium dimer, tris (dimethylamino) gallium dimer, and hexa (dimethylamino) indium gallium can be synthesized by the following chemical reaction formulas (1) to (3).

  While stirring lithium dimethylamide and indium trichloride in a solvent of n-hexane, the reaction temperature is 5 to 30 ° C., more desirably 10 to 25 ° C., and the reaction time is 24 to 120 hours, more preferably 48 to 72. It's time. After completion of the reaction, by-product lithium chloride is removed, and tris (dimethylamino) indium dimer is taken out. This reaction is represented by chemical 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 chemical formula (2).

  Next, while stirring the tris (dimethylamino) indium dimer and tris (dimethylamino) gallium dimer synthesized by the above method in an n-hexane solvent, the synthesis temperature is 5 to 30 ° C., more preferably 10 to 25 ° C. 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 chemical formula (3).

Lithium dimethylamide and the product tris (dimethylamino) indium dimer, tris (dimethylamino) gallium dimer and hexa (dimethylamino) indium gallium are all highly reactive and therefore preferably carried out in an inert gas atmosphere.
<Method for producing semiconductor particle phosphor>
≪When crystal grains have a single grain structure≫
A solution of benzene containing hexa (dimethylamino) indium gallium and tris (dimethylamino) gallium dimer as precursors of crystal particles in an arbitrary ratio of 0.1 to 10% by mass and a modified organic compound of 1 to 50% by mass (Semiconductor particle phosphor growth) and after sufficient stirring, the reaction is carried out.

  This reaction is carried out in an inert gas atmosphere, and heating is performed at a synthesis temperature of 180 to 500 ° C., more preferably 280 to 400 ° C., for 6 to 72 hours, and more preferably for 12 to 48 hours. Next, in order to remove organic impurities, washing is performed several times with n-hexane and anhydrous methanol.

  In this reaction, the formation of indium nitride / gallium mixed crystal grains and the formation of a semiconductor particle phosphor formed by coating them with a modified organic compound proceed simultaneously.

  Thereby, an indium nitride / gallium mixed crystal semiconductor particle phosphor coated with a modified organic compound can be obtained.

  Also, by reducing the amount of the modified organic compound mixed, the surface modifying power becomes weaker and the indium nitride / gallium mixed crystal grains can be enlarged. Conversely, by increasing the amount of the modified organic compound mixed, indium nitride -Gallium mixed crystal grains can be made smaller.

  This is presumably because the modified organic compound having a bond between a nitrogen atom and a carbon atom also has a function as a surfactant. That is, as the concentration in the solvent increases, the modified organic compound is likely to condense, and with this, the crystal particles are considered to become smaller during the production process.

  In FIG. 2, the flow of the manufacturing method of the semiconductor particle fluorescent substance of this invention is shown. Semiconductor particles in which the group 13 element compound is dissolved in a hydrocarbon solvent containing a modified organic compound, the mixture is heated and reacted in one step, and is coated with the modified organic compound through an optional cooling and recovery step A phosphor is manufactured.

  In the present invention, the modified organic compound and its raw material are the same as the chemical substance. Therefore, the modified organic compound used in the production process is desirably an amine which is a compound having a nonpolar hydrocarbon terminal as a hydrophobic group and an amino group as a hydrophilic group. Specific examples thereof include butylamine, t-butylamine, isobutylamine, tri-n-butylamine, triisobutylamine, triethylamine, diethylamine, hexylamine, dimethylamine, laurylamine, octylamine, tetradecylamine, and trioctylamine.

  In the present invention, a compound solution consisting only of carbon atoms and hydrogen atoms is referred to as 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. is there.

≪When crystal grains have a semiconductor core / semiconductor shell structure≫
For the semiconductor particle phosphor dissolved in a hydrocarbon solvent and having a single particle structure, produced by the above method, hexa (dimethylamino) indium gallium and tris (dimethylamino) gallium dimer Are mixed at an arbitrary ratio in an amount of 0.1 to 10% by mass. At the same time, the modified organic compound is mixed in an amount of 1 to 50% by mass, and after sufficient stirring, the reaction is performed.

  This reaction is carried out in an inert gas atmosphere, and heating is performed at a synthesis temperature of 180 to 500 ° C., more preferably 280 to 400 ° C., for 6 to 72 hours, and more preferably for 12 to 48 hours. After the reaction, washing with n-hexane and anhydrous methanol is performed several times in order to remove organic impurities.

  As a result of this reaction, a semiconductor shell is grown using crystal grains, which are a single particle structure of a semiconductor particle phosphor, as a semiconductor core, and using added hexa (dimethylamino) indium gallium and tris (dimethylamino) gallium dimer as materials. A semiconductor core / semiconductor shell structure is formed.

  In this reaction, the formation of indium nitride / gallium mixed crystal semiconductor core / semiconductor shell structure crystal particles and the formation of a semiconductor particle phosphor formed by coating them with a modified organic compound proceed simultaneously.

  By repeating this operation, the number of semiconductor shells can be increased.

  Thereby, an indium nitride / gallium mixed crystal semiconductor particle phosphor composed of crystal particles having a semiconductor core / semiconductor shell structure coated with a modified organic compound can be obtained.

Example 1
According to the chemical formulas (1) to (3), hexa (dimethylamino) indium gallium can be synthesized.

  Lithium dimethylamide and the product tris (dimethylamino) indium dimer, tris (dimethylamino) gallium dimer and hexa (dimethylamino) indium gallium were highly reactive, and all were carried out in a nitrogen gas atmosphere.

  First, 0.03 mol of lithium dimethylamide and 0.01 mol of indium trichloride were weighed in a glove box, and reacted at a heating temperature of 20 ° C. for 50 hours while stirring in n-hexane. After completion of the reaction, by-product lithium chloride was removed, and tris (dimethylamino) indium dimer was taken out (chemical formula (1)).

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

  Next, 0.02 mol of hexa (dimethylamino) indium gallium and 0.03 mol of tris (dimethylamino) gallium dimer were dissolved in a solution of 30 g of trioctylamine and 200 ml of benzene, and after stirring sufficiently, the reaction (Chemical formula (4)).

In this reaction, formation of indium nitride / gallium nitride mixed crystal particles and formation of a semiconductor particle phosphor formed by coating it with a modified organic compound proceed simultaneously, and In _0.2 Ga _0.8 N / nN (C ₈ H ₁₇ ) ₃ (semiconductor particle semiconductor structure coated with a modified organic compound) was formed.

  This reaction was performed in a nitrogen gas atmosphere, and heating was performed at a synthesis temperature of 320 ° C. and a synthesis time of 12 hours. During heating, stirring was continued using a stirring bar. Next, in order to remove organic impurities, washing was performed 3 times with n-hexane and anhydrous methanol.

The semiconductor particle phosphor obtained in this example is an indium nitride / gallium mixed crystal semiconductor particle phosphor. In this phosphor, a blue light emitting element made of a group 13 nitride can be used as an excitation light source, Emission of 405 nm with high quantum efficiency can be efficiently absorbed. The In _0.2 Ga _0.8 N crystal particles can exhibit blue light emission because the In composition ratio is adjusted so that the emission wavelength is 460 nm. Furthermore, as a result of the X-ray diffraction measurement of the obtained phosphor, the average particle diameter (diameter) of the nitride semiconductor particles estimated from the spectrum half-width is 5 nm when Scherrer's formula (Formula (2)) is used. Estimated and showed quantum size effect and improved luminous efficiency. The yield of the phosphor obtained in this example was 95%.

Where B: X-ray half width [deg],
λ: wavelength of X-ray [nm],
Θ: Bragg angle [deg],
R: Particle diameter [nm]
Indicates.

(Example 2)
A method of synthesizing a phosphor of an indium gallium nitride mixed crystal semiconductor particle coated with a modified organic compound, except that 5 g of trioctylamine is used as the modified organic compound. A semiconductor particle blue phosphor could be obtained. The obtained phosphor was able to efficiently absorb 405 nm light having a particularly high external quantum efficiency. The crystal particles had an emission wavelength of 470 nm.

  As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the crystal particle estimated from the spectrum half-width is estimated to be 50 nm using the Scherrer equation, and the emission peak intensity is the conventional indium nitride semiconductor particle phosphor. Compared to Approx. 5 times. In the production method of this example, it is considered that the surface modification power was weakened and the indium nitride / gallium mixed crystal grains were enlarged by reducing the amount of trioctylamine, which is a modified organic compound.

(Example 3)
This is a method for synthesizing a phosphor of an indium nitride semiconductor particle coated with a modified organic compound, except that 0.1 mol of tris (dimethylamino) indium dimer is used as a group 13 element compound which is a precursor of crystal particles. A semiconductor particle red phosphor could be obtained by the same production method as in Example 1. The obtained phosphor was able to efficiently absorb 405 nm light having a particularly high external quantum efficiency. The crystal particles had an emission wavelength of 620 nm.

  As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the crystal particle estimated from the spectrum half-width is estimated to be 5 nm using Scherrer's formula, showing a quantum size effect, and the emission peak intensity is Compared to the indium nitride semiconductor particle phosphor, the improvement was about 20 times.

Example 4
This is a technique for synthesizing phosphorescent gallium nitride semiconductor particles coated with a modified organic compound, except that 0.1 mol of tris (dimethylamino) gallium dimer is used as a group 13 element compound which is a precursor of crystal particles. The semiconductor particle phosphor could be obtained by the same manufacturing method as in Example 1.

  As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the crystal particle estimated from the spectrum half-width is estimated to be 5 nm using Scherrer's formula, showing a quantum size effect, and the emission peak intensity is Compared to the gallium nitride semiconductor particle phosphor, the improvement was about 20 times.

(Example 5)
13 is a technique for synthesizing a green phosphor (In _0.3 Ga _0.7 N / nN (C ₈ H ₁₇ ) ₃ ) of indium nitride-gallium mixed crystal semiconductor particles coated with a modified organic compound. Semiconductor particle green phosphor by the same production method as in Example 1 except that 0.03 mol of hexa (dimethylamino) indium gallium and 0.02 mol of tris (dimethylamino) gallium dimer are used as the group element compound (In _0.3 Ga _0.7 N / nN (C ₈ H ₁₇ ) ₃ ) could be obtained. The obtained phosphor was able to efficiently absorb 405 nm light having a particularly high external quantum efficiency. The InN crystal particle had an emission wavelength of 530 nm.

  As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the crystal particle estimated from the spectrum half-width is estimated to be 5 nm using Scherrer's formula, showing a quantum size effect, and the emission peak intensity is Compared to the indium nitride-gallium nitride mixed crystal semiconductor particle phosphor, it was improved about 20 times.

(Example 6)
13 is a technique for synthesizing a red phosphor (In _0.5 Ga _0.5 N / nN (C ₈ H ₁₇ ) ₃ ) coated with a modified organic compound, which is a precursor of crystal particles. A semiconductor particle red phosphor (In _0.5 Ga _0.5 N / nN (C ₈ H) was produced by the same production method as in Example 1 except that 0.1 mol of hexa (dimethylamino) indium gallium was used as the group element compound. ₁₇ ) We were able to get ₃ ). The obtained phosphor was able to efficiently absorb 405 nm light having a particularly high external quantum efficiency. The crystal particles had an emission wavelength of 620 nm.

  As a result of the X-ray diffraction measurement, the average particle diameter (diameter) of the crystal particle estimated from the spectrum half-width is estimated to be 5 nm using Scherrer's formula, showing a quantum size effect, and the emission peak intensity is Compared to the indium nitride-gallium nitride mixed crystal semiconductor particle phosphor, it was improved about 20 times.

(Comparative Example 1)
Trioctylphosphine (0.007 mol of gallium trichloride (GaCl ₃ ), 0.003 mol of indium trichloride (InCl ₃ ), 0.01 mol of nonamethyltrisilazane (N (Si (CH ₃ ) ₃ ) ₃ ) ( (C ₈ H ₁₇ ) ₃ P) was mixed with 30 ml. Reaction was performed at a synthesis temperature of 260 ° C. for 3 hours to synthesize a semiconductor core. The reaction solution was cooled to room temperature to obtain a semiconductor core trioctylphosphine solution.

Next, a trioctylphosphine solution of the semiconductor core, 0.009 mol of gallium trichloride (GaCl ₃ ), 0.001 mol of indium trichloride (InCl ₃ ), nonamethyltrisilazane (N (Si (CH ₃ ) ₃ ) ₃ ) 0.01 mol was mixed with 30 ml of trioctylphosphine and reacted at a synthesis temperature of 330 ° C. for 24 hours to synthesize a phosphor having a semiconductor core / semiconductor shell two-layer structure.

  In FIG. 4, the flowchart of the manufacturing method of the comparative example 1 is shown. First, the semiconductor core is manufactured by heating and cooling the raw material of the semiconductor core. And it mixes with the raw material of the semiconductor shell which includes the semiconductor core, is heated again, and is cooled, and the semiconductor particle fluorescent substance of a semiconductor core / semiconductor shell two-layer structure is obtained.

  The phosphor obtained in Comparative Example 1 has a two-layer structure for the purpose of capping defects due to dangling bonds. This comparative example has a two-step temperature rising synthesis process. In addition, since the crystal particle precursor does not have a bond between a group 13 element and a nitrogen atom, a blue light emitting element made of a group 13 nitride is used as an excitation light source, and a precise group 13 for realizing a desired emission wavelength is obtained. It is difficult to control the mixed crystal composition of elements. Moreover, since the particle size control of the crystal particles depends only on the reaction temperature and the reaction time, it is difficult to control the particle size. As a result of the X-ray diffraction measurement of the obtained phosphor, the average particle diameter (diameter) of the core estimated from the spectrum half-width is estimated to be 30 nm using the Scherrer equation, and does not show the quantum size effect. Moreover, the yield of the phosphor obtained in this comparative example was 50%. Since the synthesis step is two steps, the yield is lower than the phosphor in the present invention in which the synthesis is performed in one step.

  FIG. 3 is a diagram showing a light emission intensity-semiconductor particle diameter characteristic indicating a light emission characteristic of a semiconductor particle phosphor. In the figure, (a) shows the emission intensity of the semiconductor particle phosphor of Example 1, and (b) shows the emission intensity of the semiconductor particle phosphor of Comparative Example 1.

  In the figure, (c) is a curve showing the relationship between the emission intensity and the semiconductor particle diameter, and it can be seen that the emission intensity is extremely improved when the crystal particle diameter is not more than twice the exciton Bohr radius.

  As can be seen from FIG. 3, the semiconductor particle phosphor according to Example 1 has a smaller exciton Bohr radius and higher fluorescence efficiency than Comparative Example 1.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

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

1 is a structural diagram of a semiconductor particle phosphor according to the present invention. It is a flowchart of the manufacturing method of the semiconductor particle fluorescent substance of this invention. It is a figure which shows the light emission intensity-semiconductor particle diameter characteristic which shows the light emission characteristic of semiconductor particle fluorescent substance. 6 is a flowchart of the manufacturing method of Comparative Example 1. FIG.

Explanation of symbols

  10 Semiconductor particle phosphor, 11 crystal particle, 12 modified organic compound.

Claims (5)

A crystal particle including a bond between a group 13 element and a nitrogen atom is coated with a modified organic compound including at least a bond between a nitrogen atom and a carbon atom, and the nitrogen atom of the modified organic compound is a group 13 of the crystal particle. A method for producing a semiconductor particle phosphor that coordinates to an element, comprising:
A method for producing a semiconductor particle phosphor, comprising a step of heating a synthetic solution in which a group 13 element compound, the modified organic compound, and a hydrocarbon solvent composed of only carbon atoms and hydrogen atoms are mixed. The method for producing a semiconductor particle phosphor according to claim 1 , wherein the group 13 element is In and / or Ga. The hydrocarbon solvent is selected from the group consisting of n-pentane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane, cycloheptane, benzene, toluene, o-xylene, m-xylene and p-xylene. at least at one or more, the method of manufacturing a semiconductor particle phosphor according to claim 1 which is selected. 2. The method for producing a semiconductor particle phosphor according to claim 1 , wherein a temperature for heating the synthetic solution is 180 to 500 ° C. 3. The method for producing a semiconductor particle phosphor according to claim 1 , wherein the time for heating the synthetic solution is 6 to 72 hours.

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