JP2017218574A - Nanoparticle phosphor element and light-emitting element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nanoparticle phosphor element in which semiconductor nanoparticle phosphors are satisfactorily dispersed without aggregation in a medium and shows excellent quantum efficiency, and a light-emitting element prepared with the nanoparticle phosphor element.SOLUTION: A nanoparticle phosphor element has a capsule-like material having a plurality of recesses on its surface, a medium encapsulated in the capsule-like material, and semiconductor nanoparticle phosphors dispersed in the medium. There is also provided a light-emitting element having a sealer, and the nanoparticle phosphor elements dispersed in the sealer.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a nanoparticle phosphor device comprising a capsule, a medium enclosed in the capsule, and a semiconductor nanoparticle phosphor dispersed in the medium.

  It is known that when the size of the semiconductor nanoparticle phosphor is reduced to an exciton Bohr radius, a quantum size effect is exhibited. The quantum size effect is that when the size of a material is reduced, electrons in the material cannot freely move, and the energy of the electrons is not arbitrary and can take only a specific value. It is also known that the energy state of electrons changes as the size of the semiconductor nanoparticle phosphor confining electrons changes, and the wavelength of light generated from the semiconductor nanoparticle phosphor becomes shorter as the size decreases. It has been. Semiconductor nanoparticle phosphors exhibiting such a quantum size effect have been studied for their application as phosphors.

  Semiconductor nanoparticle phosphors have a large specific surface area and high surface activity, so that they are difficult to stabilize chemically and physically. Therefore, methods for stabilizing semiconductor nanoparticle phosphors have been proposed.

  For example, in Japanese translations of PCT publication No. 2013-505347 (Patent Document 1), a plurality of coated primary particles, each primary particle is composed of a primary matrix material, and includes a group of semiconductor nanoparticles, Each primary particle is disclosed as a plurality of coated primary particles provided with a layer of surface coating material individually.

Special table 2013-505347 gazette

  In the technique of Patent Document 1, since a general material such as a polymer or glass is used as a matrix material, aggregation of the semiconductor nanoparticle phosphor occurs in the matrix, and the quantum efficiency of the semiconductor nanoparticle phosphor decreases. There was a problem.

  Therefore, the present invention provides a nanoparticle phosphor element in which the semiconductor nanoparticle phosphor is well dispersed in the medium without agglomeration and exhibits excellent quantum efficiency, and a light emitting element using the nanoparticle phosphor element. The purpose is to provide.

  The nanoparticle phosphor element of the present invention comprises a capsule having a plurality of recesses on the surface, a medium enclosed in the capsule, and a semiconductor nanoparticle phosphor dispersed in the medium. Features.

  In the nanoparticle phosphor element of the present invention, the capsule is preferably composed of at least two layers.

  In the present invention, the medium may be a liquid, and in this case, the medium is preferably an ionic liquid.

  In the present invention, the medium may be a solid, and in this case, the medium is preferably a resin including a structural unit derived from an ionic liquid having a polymerizable functional group.

  The present invention also provides a light emitting device comprising a sealing material and the above-described nanoparticle phosphor device of the present invention dispersed in the sealing material.

  ADVANTAGE OF THE INVENTION According to this invention, the semiconductor nanoparticle fluorescent substance is disperse | distributed favorably in a matrix, and the light emitting element using the nanoparticle fluorescent element which shows the outstanding quantum efficiency, and this nanoparticle fluorescent element is provided. it can.

It is a figure which shows typically the nanoparticle fluorescent substance element 1 and light emitting element 11 which concern on Embodiment 1. FIG. It is a figure which shows typically the nanoparticle fluorescent substance element 1 and light emitting element 11 which concern on Embodiment 1. FIG. 3 (a) is a scanning electron micrograph of the nanoparticle phosphor element 1 of the present invention, FIG. 3 (b) is a fluorescence micrograph image of the nanoparticle phosphor element 1 of the present invention, and FIG. 3 (c). These are scanning electron micrographs of the nanoparticle phosphor element 21 of the present invention. It is a figure which shows typically the nanoparticle fluorescent substance element 21 which concerns on Embodiment 2. FIG. It is a figure which shows typically the light emitting element 41 which concerns on Embodiment 3. FIG.

  Hereinafter, in the drawings of the present application, the same reference numerals represent the same or corresponding parts. In addition, dimensional relationships such as length, size, and width in the drawings are appropriately changed for clarity and simplification of the drawings, and do not represent actual dimensions.

[Embodiment 1]
<Nanoparticle phosphor element>
The nanoparticle phosphor element according to Embodiment 1 will be described with reference to FIGS. 1 and 2 are diagrams schematically showing a nanoparticle phosphor element 1 and a light emitting element 11 according to Embodiment 1. FIG. In FIG. 1, the nanoparticle phosphor element 1 shown on the upper left side with respect to the paper surface of FIG. 1 is an enlarged view of a part of the light emitting element 11 shown on the lower side, and the upper right side with respect to the paper surface of FIG. On the side, the semiconductor nanoparticle phosphor 2 and the medium 3 included in the nanoparticle phosphor element 1 are partially enlarged. Further, in FIG. 2, the nanoparticle phosphor element 1 shown on the upper side with respect to the paper surface of FIG. 2 shows an enlarged part of the light emitting element 11 shown on the lower side.

  As shown in FIG. 1 and FIG. 2, the nanoparticle phosphor element 1 includes a capsule 4 having a plurality of recesses 4 a and 4 b on the surface, a medium 3 enclosed in the capsule 4, and the medium 3 is basically provided with a semiconductor nanoparticle phosphor 2 dispersed in 3.

(Semiconductor nanoparticle phosphor)
The semiconductor nanoparticle phosphor 2 is a nano-sized phosphor particle. The particle diameter of the semiconductor nanoparticle phosphor can be appropriately selected according to the raw material and the desired emission wavelength, and is not particularly limited, but is preferably in the range of 1 to 20 nm, and in the range of 2 to 5 nm. More preferably. This is because when the particle size of the semiconductor nanoparticle phosphor is less than 1 nm, the ratio of the surface area to the volume increases, so that surface defects tend to be dominant and the effect tends to decrease. This is because when the particle size of the body exceeds 20 nm, the dispersed state tends to decrease and aggregation / sedimentation tends to occur. Here, when the shape of the semiconductor nanoparticle phosphor is spherical, the particle size refers to, for example, an average particle size measured by a particle size distribution measuring device or a particle size observed by an electron microscope. Moreover, when the shape of the semiconductor nanoparticle phosphor is rod-shaped, the particle size refers to the size of the short axis and the long axis measured by, for example, an electron microscope. Furthermore, when the shape of the semiconductor nanoparticle phosphor is a wire shape, the particle size refers to the size of the short axis and the long axis measured by, for example, an electron microscope.

  The semiconductor nanoparticle phosphor 2 has, for example, a core-shell structure of a nanoparticle core made of a compound semiconductor and a coating layer made of a shell layer that covers the nanoparticle core. Moreover, in the example shown in FIG. 1, the organic modification group 8 couple | bonds with the outer side of a shell layer. The organic modifying group 8 preferably includes a polar functional group.

The nanoparticle core is made of a compound semiconductor. The composition of the compound semiconductor constituting the nanoparticle core is, for example, InN, InP, InAs, InSb, InBi, InGaN, InGaP, GaP, AlInN, AlInP, AlGaInN, AlGaInP, CdS, CdSe, CdTe, CdZnS, CdZnSe, CdZnTe, CdZnSSe, CdZnSeTe, In ₂ S ₃ , In ₂ Se ₃ , Ga ₂ Se ₃ , In ₂ Te ₃ , Ga ₂ Te ₃ , CuInS ₂ , CuInSe ₂ , CuInTe ₂ and the like. The compound semiconductor having such a composition has band gap energy that emits visible light having a wavelength of 380 nm to 780 nm. Therefore, a nanoparticle core capable of emitting any visible light can be formed by controlling the particle size and the mixed crystal ratio.

  InP, GaP, or CdSe is preferably used as the semiconductor constituting the nanoparticle core. The reason is that InP, GaP, and CdSe are easy to manufacture because there are few constituent materials, and also show high quantum yield, and show high luminous efficiency when irradiated with LED light. The quantum yield here is the ratio of the number of photons emitted as fluorescence to the number of absorbed photons.

The shell layer is made of a compound semiconductor formed by taking over the crystal structure of the nanoparticle core. The shell layer is a layer formed by growing a semiconductor crystal on the surface of the nanoparticle core, and the nanoparticle core and the shell layer are bonded by a chemical bond. The shell layer is formed of, for example, GaAs, GaP, GaN, GaSb, InAs, InP, InN, InSb, AlAs, AlP, AlSb, AlN, ZnO, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, CdZnS, CdZnSe, CdZnTe, It is preferably at least one selected from the group consisting of CdZnSSe, CdZnSeTe, In ₂ O ₃ , Ga ₂ O ₃ , In ₂ S ₃ , Ga ₂ S ₃ and ZrO ₂ . The thickness of the shell layer is preferably 0.1 to 10 nm. The shell layer may have a multilayer structure composed of a plurality of shell layers.

  The outer surface of the shell layer is bonded to the organic modifying group 8. The organic modifying group 8 is formed by reacting and bonding the modified organic compound to the outer surface of the shell layer. Thereby, the dangling bond on the surface of the shell layer is capped by the organic modifying group, and the surface defect of the shell layer is suppressed, so that the luminous efficiency of the nanoparticle core is improved.

  As described above, by using the semiconductor nanoparticle phosphor 2 having the organic modifying group 8 on the surface, aggregation of the semiconductor nanoparticle phosphors 2 can be prevented. For this reason, the semiconductor nanoparticle phosphor 2 is easily dispersed in the medium 3.

  The modified organic compound preferably has a polar functional group at the terminal. When the modified organic compound is reacted with the outer surface of the shell layer, the polar functional group is disposed on the surface of the semiconductor nanoparticle phosphor 2. Therefore, since the surface of the semiconductor nanoparticle phosphor 2 has polarity, the semiconductor nanoparticle phosphor 2 can be favorably dispersed in the matrix including the structural unit derived from the ionic liquid.

  Examples of the polar functional group include a carboxyl group, a hydroxyl group, a thiol group, a cyano group, a nitro group, an ammonium group, an imidazolium group, a sulfonium group, a pyridinium group, a pyrrolidinium group, and a phosphonium group.

  The polar functional group in the modified organic compound is preferably an ionic functional group. Since the ionic functional group has a high polarity, the semiconductor nanoparticle phosphor having the ionic functional group on the surface is used when the medium is a resin containing a ionic liquid or a structural unit derived from the ionic liquid. Dispersibility in the medium is very excellent. Further, when the semiconductor nanoparticle phosphor is encapsulated in a medium that is an ionic liquid or a resin containing a structural unit derived from the ionic liquid, electrostatic discharge due to the positive and negative charges of the ionic liquid is caused. By the action, the stability of the semiconductor nanoparticle phosphor is greatly improved. The ionic liquid will be described later.

  Examples of the ionic functional group include an ammonium group, an imidazolium group, a sulfonium group, a pyridinium group, a pyrrolidinium group, and a phosphonium group.

  As long as the modified organic compound has a polar functional group at the terminal, other structures are not particularly limited. Specifically, dimethylaminoethanethiol (DAET), carboxydecanethiol (CDT), hexadecanethiol (HDT), n-trimethoxysilylbutanoic acid (TMSBA), 3-aminopropyldimethylethoxysilane (APDMES), 3-aminopropyltrimethoxysilane (APTMS), N-trimethoxysilylpropyl-N, N, N-trimethylammonium chloride (TMSP-TMA), 3- (2-aminoethylamino) propyltrimethoxysilane (AEAPTMS), 2-Cyanoethyltriethoxysilane or the like can be used.

  One type of semiconductor nanoparticle phosphor may be used, or two or more types may be used in combination.

(Medium)
The medium 3 may be a liquid or a solid. When the medium 3 is a liquid, examples of the medium include ionic liquid, octadecene (ODE), isobutyl alcohol, toluene, xylene, ethylene glycol monoethyl ether, and the like. When the medium 3 is a solid, the medium includes a resin containing a structural unit derived from an ionic liquid having a polymerizable functional group, epoxy, silicone, (meth) acrylate, silica glass, polystyrene, polypyrrole, polyimide, poly Examples include imidazole, polysulfone, polythiophene, polyphosphate, poly (meth) acrylate, polyacrylamide, polypeptide, polysaccharide, and the like. Among these, it is preferable to use a resin containing a structural unit derived from an ionic liquid having a polymerizable functional group when the medium 3 is a liquid and when the medium 3 is a solid.

In the present specification, the “ionic liquid” means a salt in a molten state (room temperature molten salt) even at room temperature (for example, 25 ° C.), and the following general formula (1):
X ⁺ Y ⁻ (1)
Indicated by

In the general formula (1), X ⁺ is a cation selected from imidazolium ions, pyridinium ions, phosphonium ions, aliphatic quaternary ammonium ions, pyrrolidinium, and sulfonium. Of these, aliphatic quaternary ammonium ions are particularly preferred cations because of their excellent thermal and atmospheric stability.

In the general formula (1), Y ⁻ represents tetrafluoroborate ion, hexafluorophosphate ion, bistrifluoromethylsulfonylimido ion, perchlorate ion, tris (trifluoromethylsulfonyl) carbonate ion, trifluoro. An anion selected from lomethanesulfonate ion, trifluoroacetate ion, carboxylate ion, and halogen ion. Among these, bistrifluoromethylsulfonylimido ion is mentioned as a particularly preferable anion because it has excellent thermal and atmospheric stability.

  As the ionic liquid, an ionic liquid having a polymerizable functional group or an ionic liquid having no polymerizable functional group can be used. Examples of the ionic liquid having a polymerizable functional group include 2- (methacryloyloxy) -ethyltrimethylammonium bis (trifluoromethanesulfonyl) imide (hereinafter abbreviated as “MOE-200T”), 1- (3- And acryloyloxy-propyl) -3-methylimidazolium bis (trifluoromethanesulfonyl) imide. Examples of the ionic liquid having no polymerizable functional group include N, N, N-trimethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-methyl-2- (2- And methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (hereinafter abbreviated as “DEME-TFSI”).

  A resin containing a structural unit derived from an ionic liquid having a polymerizable functional group can be formed, for example, by curing the ionic liquid with heat or light using a crosslinking agent.

  When the medium 3 is an ionic liquid or a resin containing a structural unit derived from the ionic liquid, the semiconductor nanoparticle phosphor 2 dispersed in the medium 3 becomes an ionic liquid in the medium 3. Due to the electrostatic action of the positive charges 6 and the negative charges 7 derived therefrom, there is an advantage that it can be well dispersed in the medium 3. Furthermore, due to the electrostatic action derived from the ionic liquid in the medium 3, the organic modifying group 8 on the surface of the semiconductor nanoparticle phosphor 2 is stabilized, and dangling bonds due to detachment from the surface of the semiconductor nanoparticle phosphor Since generation | occurrence | production is suppressed, the fall of the quantum efficiency of a semiconductor nanoparticle fluorescent substance can be suppressed. Among them, when the organic modifying group 8 includes a polar functional group or an ionic functional group, and the polar functional group or the ionic functional group is present on the surface of the semiconductor nanoparticle phosphor, the charge contained in these functional groups, Due to the electrostatic interaction with the positive charges 6 and the negative charges 7 derived from the ionic liquid, the stability of the semiconductor nanoparticle phosphor 2 is further improved. Moreover, since there is almost no volatility in a normal use temperature range, there is an advantage that it can be used at a high temperature at which a general medium volatilizes.

  Note that when a liquid other than an ionic liquid is used as the liquid medium, it is difficult to volatilize under normal use conditions (such as LED), and the amount of medium is reduced due to the volatilization of the medium or the capsule is broken due to vapor pressure. It is preferable to use a medium having a high boiling point (for example, a boiling point of 200 ° C. or higher) such as the above-mentioned octadecene from the viewpoint that a light-emitting element that hardly occurs and has high stability can be obtained.

(Capsule)
The capsule 4 in the example shown in FIGS. 1 and 2 is a hollow sphere having a plurality of recesses on the surface thereof, like a golf ball. The capsule-like material in the present invention has a concave shape on the surface, and the shape of the capsule-like material is spherical if it can enclose the medium 3 in which the semiconductor nanoparticle phosphor 2 is dispersed in the internal space. (Spherical object, oblate object, oblong object), hexahedral object, tetrahedral object, etc., but not particularly limited, as shown in the examples shown in FIGS. 1 and 2 from the viewpoint of easy control of shape and size. A hollow sphere is preferable.

  In the nanoparticle phosphor element 1 of the present invention, the encapsulation of the semiconductor nanoparticle phosphor can be suppressed by encapsulating the medium 3 in which the semiconductor nanoparticle phosphor 2 is dispersed in the capsule 4. Degradation of the semiconductor nanoparticle phosphor due to aggregation can be suppressed. Moreover, invasion of oxygen and moisture into the medium 3 can be suppressed, and deterioration of the semiconductor nanoparticle phosphor 2 due to oxygen and moisture can be suppressed.

  Furthermore, in the nanoparticle phosphor element 1 of the present invention, the nanoparticle phosphor element 1 is sealed as shown in FIGS. 1 and 2 by using a capsule 4 having a plurality of recesses on the surface. When the light-emitting element 11 of the present invention is sealed by the material 13, there is an advantage that the contact between the capsule-like material 4 and the sealing material 13 is good (the contact area is large). Thereby, since heat easily escapes from the nanoparticle phosphor element 1 to the sealing material 13, the amount of heat accumulated in the nanoparticle phosphor element 1 can be reduced, and the semiconductor nanoparticle phosphor 2 is caused by heat. It can suppress that it deteriorates and efficiency falls. That is, as schematically shown in FIG. 2, in the light emitting element 11, the excitation light L <b> 1 from the light source 12 is incident on the semiconductor nanoparticle phosphor 2 to generate fluorescence L <b> 2. At this time, heat T is generated from the semiconductor nanoparticle phosphor 2 together with the fluorescence L2. In the present invention, as described above, the heat T from the nanoparticle phosphor element 1 at the time of light emission can be released to the sealing material 13, and the efficiency reduction of the semiconductor nanoparticle phosphor 2 due to heat can be suppressed.

  The size of the capsule 4 is not particularly limited. For example, when the capsule 4 is a hollow sphere as shown in FIGS. 1 and 2, the diameter (the diameter of the portion other than the concave portion) is 50 nm to 1 mm. It is preferably within the range, and more preferably within the range of 100 nm to 100 μm. When the diameter of the capsule-like material 4 is less than 100 nm, the surface area / volume ratio per particle is increased, so that loss due to scattering of excitation light tends to increase. When the thickness exceeds 1 mm, it tends to be difficult to disperse in a sealing material described later in the same process as that of a conventional phosphor.

  For example, the thickness of the capsule 4 (the thickness of the portion other than the concave portion) is preferably 0.5 nm to 0.5 mm, and more preferably 10 nm to 100 μm. When the thickness of the capsule 4 is less than 0.5 nm, the medium 3 tends to be insufficiently protected, and when the thickness of the capsule 4 exceeds 0.5 mm, the excitation light Loss due to scattering tends to increase.

  Here, FIG. 3A is a scanning electron microscope (SEM) photograph (5000 times) of the nanoparticle phosphor element 1 of the present invention (Example 1 described later), and FIG. Fluorescence microscope image photograph (1000 times) of the nanoparticle phosphor element 1 (Example 1 described later), FIG. 3C is a scanning electron of the nanoparticle phosphor element 21 (Example 2 described later) of the present invention. It is a microscope (SEM) photograph (5000 times). The shape, size, thickness, concave portion, and the like of the capsule 4 in the nanoparticle phosphor element of the present invention can be confirmed by using a scanning electron microscope, a fluorescence microscope, a transmission electron microscope, or the like. 3A shows a case where the capsule-like material 4 is composed of two layers (having the coating layer 5), and FIG. 3C shows a case where the capsule-like material 4 is composed of one layer. As long as it can have a plurality of concave portions on the surface as in (a), the capsule-like object 4 may have a coating layer 5 on the outside thereof. Moreover, from FIG.3 (b), light emission of the green fluorescence from a semiconductor nanoparticle fluorescent substance can be confirmed with the fluorescence microscope image at the time of 405 nm irradiation.

  The capsule 4 (including the coating layer 5) is not particularly limited as long as it is a material that blocks oxygen and moisture, and an inorganic material, a polymer material, or the like can be used. In the case where the capsule is composed of at least two layers, the number of layers is not particularly limited as long as it is two or more, and the material of each layer is not particularly limited as long as it has an oxygen and moisture barrier property. The materials for each layer may all be the same, all may be different, or only a part may be the same.

  Inorganic materials have excellent oxygen and moisture barrier properties. As the inorganic material, for example, silica, metal oxide, metal nitride, or the like can be used.

  Since the polymer material has flexibility, the impact resistance of the nanoparticle phosphor element 1 is improved when it is used as the material of the capsule 4. Furthermore, since the polymer material can be formed under milder conditions than the inorganic material, process damage to the medium 3 and the semiconductor nanoparticle phosphor 2 can be suppressed. Polymer materials include polyamideimide, acrylate polymer, epoxide, polyamide, polyimide, polyester, polycarbonate, polythioether, polyacrylonitrile, polydiene, polystyrene polybutadiene copolymer, parylene, silica-acrylate hybrid, polyetheretherketone, polyvinylidene fluoride, poly Vinylidene chloride, polydivinylbenzene, polyethylene, polypropylene, polyethylene terephthalate, polyisobutylene, polyisoprene, cellulose derivatives, polytetrafluoroethylene, and the like can be used. Moreover, when the capsule-like thing 4 consists of two layers, a fluorine-type polymer (For example, Cytop (made by Asahi Glass Co., Ltd.) etc.) can also be used suitably for the coating layer 5 used as an outer layer.

  The capsule-like object 4 shown in FIG. 1 and FIG. 2 has two types of depressions: a recess 4a that communicates with the internal space of the capsule-like object 4, and a recess 4b that does not communicate with the internal space. The opening shape of the recess is not particularly limited, such as a circular shape or an elliptical shape. The opening diameter of the recessed portion (diameter when the opening shape of the recessed portion is circular) is within a range of 20 nm to 10 μm from the viewpoint of exhibiting excellent heat dissipation by good contact with the sealing material 13 described above. It is preferable that it is within a range of 100 nm to 10 μm.

  The diameter of the portion communicating with the internal space of the recess 4a is preferably in the range of 20 nm to 10 μm, and preferably in the range of 100 nm to 10 μm. The diameter of the portion communicating with the internal space of the recess 4 a is 10 μm or less, so that even when the liquid medium 3 is sealed inside the capsule-like material 4, the medium 3 is outside the capsule-like material 4. Can be prevented from flowing out. In addition, since the diameter of the portion communicating with the internal space of the recess 4a is within the above-described range, the medium 3 in which the semiconductor nanoparticle phosphor 2 is dispersed can be efficiently injected into the capsule-like material 4. As long as the diameter of the portion communicating with the internal space of the recess 4a is 20 nm or more, the inside of the recess 4a is better than any semiconductor nanoparticle phosphor having a particle diameter of 1 to 20 nm which is preferable as the semiconductor nanoparticle phosphor. This is because the diameter of the portion communicating with the space is larger, and the semiconductor nanoparticle phosphor can easily pass through the portion communicating with the internal space of the recess 4a. The portion communicating with the internal space of the recess 4a is formed after encapsulating the medium 3 in which the semiconductor nanoparticle phosphor 2 is dispersed in the capsule 4 (for example, as shown in FIGS. 1 and 2, the coating layer 5 Etc.) can be sealed.

  In addition, the depth of the recess 4b that does not communicate with the internal space is not particularly limited. However, from the viewpoint of exhibiting excellent heat dissipation due to good contact with the sealing material 13 described above, 1 / th of the thickness of the capsule 4 It is preferably within the range of 100 to 1/2.

  Further, the pitch between the recesses (the linear distance between the recesses) is preferably in the range of 20 nm to 100 μm, and more preferably in the range of 20 nm to 10 μm. When the pitch is less than 20 nm, the ratio of the capsule-like material to the opening diameter is reduced, and the protection of the medium 3 tends to be insufficient, and when the pitch exceeds 100 μm, the entire surface is not covered. The ratio of the recesses is small, and there is a tendency that excellent heat dissipation due to good contact with the sealing material 13 cannot be exhibited.

<Method for producing nanoparticle phosphor element>
The nanoparticle phosphor element can be produced by encapsulating the medium 3 in which the semiconductor nanoparticle phosphor 2 is dispersed in the capsule 4 using an existing capsule manufacturing method. An example of a specific manufacturing method is shown below.

(Manufacture of semiconductor nanoparticle phosphors)
The manufacturing method of the semiconductor nanoparticle phosphor 2 is not particularly limited, and any manufacturing method may be used. From the viewpoint that the method is simple and low in cost, it is preferable to use a chemical synthesis method as a method for producing the semiconductor nanoparticle phosphor 2. In the chemical synthesis method, a target product can be obtained by dispersing a plurality of starting materials containing the constituent elements of the product in a medium and reacting them. Examples of such chemical synthesis methods include a sol-gel method (colloid method), a hot soap method, a reverse micelle method, a solvothermal method, a molecular precursor method, a hydrothermal synthesis method, or a flux method. From the viewpoint that the nanoparticle core 2 made of a compound semiconductor material can be suitably manufactured, it is preferable to use a hot soap method. Below, an example of the manufacturing method of the semiconductor nanoparticle fluorescent substance 2 which has a core-shell structure by a hot soap method is shown.

  First, the nanoparticle core is synthesized in a liquid phase. For example, when producing a nanoparticle core made of InN, a flask or the like is filled with 1-octadecene (solvent for synthesis), and tris (dimethylamino) indium and hexadecanethiol (HDT) are mixed. After sufficiently stirring this liquid mixture, it is made to react at 180-500 degreeC. Thereby, the nanoparticle core 2 which consists of InN is obtained, and HDT is couple | bonded with the outer surface of the obtained nanoparticle core. HDT may be added after the growth of the shell layer.

  The synthesis solvent used in the hot soap method is preferably a compound solution composed of carbon atoms and hydrogen atoms (hereinafter referred to as “hydrocarbon solvent”). This prevents water or oxygen from being mixed into the synthesis solvent, thereby preventing the nanoparticle core from being oxidized. Examples of the hydrocarbon solvent include n-pentane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane, cycloheptane, benzene, toluene, o-xylene, m-xylene, and p-xylene. It is preferable that

  In principle, in the hot soap method, the longer the reaction time, the larger the particle diameter of the nanoparticle core. Therefore, the size of the nanoparticle core can be controlled to a desired size by performing liquid phase synthesis while monitoring the particle diameter by photoluminescence, light absorption, dynamic light scattering, or the like.

  Next, a reaction reagent that is a raw material of the shell layer is added to the solution containing the nanoparticle core, and the reaction is performed by heating. Thereby, the starting material of the semiconductor nanoparticle phosphor is obtained. In the starting material of the obtained semiconductor nanoparticle phosphor, the outer surface of the nanoparticle core is covered with a shell layer, and HDT is bonded to the outer surface of the shell layer.

  Subsequently, the modified organic compound is added to the solution containing the starting material of the semiconductor nanoparticle phosphor and reacted at room temperature to 300 ° C. As a result, the bond between the outer surface of the shell layer and HDT is released, the modified organic compound is bonded to the outer surface of the shell layer, and the organic modifying group 8 is formed. In this way, the semiconductor nanoparticle phosphor 2 is obtained.

  A modified organic compound may be added in place of HDT when producing the nanoparticle core. Thus, when obtaining the semiconductor nanoparticle fluorescent substance 2, it is not necessary to add a modified organic compound after formation of a shell layer.

(Preparation of capsule 4)
The obtained semiconductor nanoparticle phosphor 2 is dispersed in the medium 3. The volume ratio of the semiconductor nanoparticle phosphor 2 to the medium 3 can be a value corresponding to the use of the light emitting device, and is preferably 0.000001 or more and 10 or less, for example.

  Next, the capsule 4 having a plurality of recesses on the surface was prepared by the following method. An aqueous phase (W1 phase) prepared with an aqueous solution of sodium silicate and an aqueous solution of polymethyl methacrylate, an n-hexane phase (O phase) prepared with Tween 80 (polyoxyethylene sorbitan monooleate) and Span 80 (sorbitan monooleate), carbonic acid An aqueous phase (W2 phase) prepared with ammonium hydrogen was prepared. Next, the W1 phase was added to the O phase and then emulsified with a homogenizer at a rotational speed of 8000 rpm to prepare a W1 / O phase. This was immediately added to the W2 phase and stirred at 35 ° C. for 2 hours with a magnetic stirrer. . Thereafter, water or ethanol was added to the solution, the mixture was centrifuged, the operation of removing the supernatant was repeated, washed, and then filtered to obtain a precipitate. Thereafter, the precipitate is dried at 100 ° C. for 12 hours, and then calcined at 700 ° C. for 5 hours to obtain hollow silica capsules having pores with an average particle diameter of about 10 μm. A medium in which the semiconductor nanoparticle phosphor 2 is dispersed is injected into the capsule 4 thus prepared, and the medium 3 is cured as necessary (for example, an ionic liquid is cured and ionized). The nanoparticle phosphor element can also be produced by forming a resin containing a structural unit derived from a functional liquid. Thereby, when encapsulating in a capsule-like material, a nanoparticle phosphor element is suitably produced without causing process damage to the semiconductor nanoparticle phosphor 2 or the medium 3 in which the semiconductor nanoparticle phosphor 2 is dispersed. can do. In addition, the hardening process of an ionic liquid can use the photocuring method which hardens | cures by applying an ultraviolet-ray, and the thermosetting method which hardens by applying a heat | fever.

<Light emitting element>
As shown in FIGS. 1 and 2, the light-emitting element 11 includes a sealing material 13 and the above-described nanoparticle phosphor element 1 of the present invention dispersed in the sealing material 13. Moreover, the light emitting element 11 of the example shown in FIGS. 1 and 2 includes a light source 12 integrally covered with a sealing material 13. In the light emitting device of the present invention, one type of nanoparticle phosphor device may be used, or two or more types may be used in combination.

  The nanoparticle phosphor element 1 of the present invention described above has excellent quantum efficiency. Furthermore, since the surface is coated with the support, the nanoparticle phosphor elements 1 do not aggregate in the encapsulant 13 and can be well dispersed. Therefore, the light emitting element 11 including the nanoparticle phosphor element 1 can have excellent light emission efficiency.

  As the sealing material 13, it is preferable to use a glass material or a polymer material. As the glass material, for example, tetramethoxysilane (TMOS), tetraethoxysilane (TEOS), tetrapropoxysilane, tetrabutoxysilane, or the like can be used. Examples of the polymer material include acrylic resins such as polymethyl methacrylate (PMMA), epoxy resins composed of bisphenol A and epichlorohydrin, MOE-200T (2- (methacryloyloxy) -ethyltrimethylammonium bis (trifluoromethanesulfonyl) imide, and the like. ), 1- (3-acryloyloxy-propyl) -3-methylimidazolium ethyltrimethylammonium bis (trifluoromethanesulfonyl) imide and the like, a resin containing a structural unit derived from an ionic liquid can be used.

  The volume ratio of the nanoparticle phosphor element 1 to the sealing material 13 can be a value corresponding to the use of the light emitting element, and is preferably 0.000001 or more and 10 or less, for example. When importance is attached to the transparency of the light emitting element, the volume ratio of the nanoparticle phosphor element to the sealing material is preferably 0.2 or less. When the volume ratio is 0.2 or less, a light-emitting element having high transparency can be obtained. Moreover, when importance is attached to the light emission amount of the light emitting device, the volume ratio of the nanoparticle phosphor element to the sealing material is preferably 0.00001 or more. When the volume ratio is 0.00001 or more, a light emitting device having a large light emission amount can be obtained.

  The sealing material 13 preferably contains 80% by volume or more of glass material or polymer material, more preferably 90% by volume or more. When the sealing material 13 contains 80% by volume or more of a glass material or a polymer material, a light emitting device having high transparency or high luminous efficiency can be obtained, and when it contains 90% by volume or more, higher transparency or high luminous efficiency can be obtained. It can be set as the light emitting element which has.

  The combination of the kind of nanoparticle phosphor element and the kind of sealing material is not particularly limited, and can be selected according to the use of the light emitting element.

<Method for manufacturing light-emitting element>
When encapsulating the nanoparticle phosphor element 1 in the encapsulant 13, a process of curing after dispersing the nanoparticle phosphor element 1 in the encapsulant 13 is performed.

  When a glass material is used as the sealing material 13, the nanoparticle phosphor element 1 is dispersed in the glass material by stirring a solution in which the glass material and the nanoparticle phosphor element 1 are mixed. Next, the glass material is subjected to a condensation reaction and cured. Heating may be performed to increase the progress of the condensation reaction, or an acid or base may be added to the system.

  When a polymer material is used as the sealing material 13, the nanoparticle phosphor element 1 is dispersed in the polymer material by stirring a solution in which the polymer material and the nanoparticle phosphor element 1 are mixed. Next, the polymer material is subjected to a condensation reaction, and cured to be resinized (solidified). As a curing method, there can be used a photocuring method in which ultraviolet rays are applied to cure, or a thermosetting method in which heat is applied to cure.

[Embodiment 2]
<Nanoparticle phosphor element>
FIG. 4 is a diagram schematically showing the nanoparticle phosphor element 21 according to the second embodiment. The nanoparticle phosphor element 21 of the example shown in FIG. 4 is different from the nanoparticle phosphor element 1 of the example shown in FIG. 1 only in that the capsule 4 is only one layer and does not have a coating layer. . Even in the case of the nanoparticle phosphor 21 as shown in FIG. 4, as described above, the heat T generated when the fluorescence L2 is emitted from the semiconductor nanoparticle phosphor 2 due to the incidence of the excitation light L <b> 1 Deterioration of the semiconductor nanoparticle phosphor due to heat can be suppressed by making good contact with the sealing material 13 by the plurality of concave portions on the surface and efficiently escaping. In addition, even if it does not have a coating layer as shown in FIG. 4 or the medium 3 is a liquid, since the medium 3 is held in the internal space of the capsule-like object 4 by capillary action, Does not come out.

[Embodiment 3]
<Light emitting element>
FIG. 5 is a diagram schematically showing the light emitting element 41 according to the third embodiment. As shown in FIG. 5, the light emitting element 41 of the present invention includes a first light emitting layer 42 in which a first nanoparticle phosphor element 44 is dispersed in a sealing material 49, and a second nanoparticle in a sealing material 56. It may have a multilayer structure including the second light emitting layer 43 in which the particle phosphor element 51 is dispersed. In this case, for example, the first nanoparticle phosphor element 44 included in the first light-emitting layer 42 has a plurality of recesses 47a and 47b in the medium 46 in which the semiconductor nanoparticle phosphor 45 emitting red light is dispersed. The first light emitting layer 42 functions as a red light emitting layer by being encapsulated in a capsule 47 having the layer 48. Further, the second nanoparticle phosphor element 51 included in the second light emitting layer 43 has a plurality of concave portions 54a and 54b in a medium 53 in which a semiconductor nanoparticle phosphor 52 emitting green light is dispersed. The second light emitting layer 43 functions as a green light emitting layer. For example, a blue light-emitting LED chip is used as the light source 12, and a first light-emitting layer 42 that functions as a red light-emitting layer and a second light-emitting layer 43 that functions as a green light-emitting layer are stacked in this order on the first light-emitting layer. Since reabsorption of energy from the two light emitting layers 43 to the first light emitting layer 42 is unlikely to occur, the light emitting efficiency of the light emitting element 41 is improved.

<Method for manufacturing light-emitting element>
An example of a method for manufacturing a light-emitting element having a multilayer structure will be described below. Hereinafter, a case of a light-emitting element having a two-layer structure will be described, but a case of a three-layer structure or more can be basically manufactured by the same method. First, two types of nanoparticle phosphor elements having different sizes are prepared. A solution of these two types of nanoparticle phosphor elements is mixed in an acrylic resin material and dropped onto a blue light emitting LED chip, and then heat curing is performed. During heating and curing, the nanoparticle phosphor element with a large particle size settles after a lapse of a certain period of time, and as a light emitting device, a lower layer containing a nanoparticle phosphor element with a large particle size mainly, and a nanoparticle fluorescence with a mainly small particle size A two-layer structure including an upper layer including body elements is formed.

  According to said manufacturing method, complicated processes, such as forming each layer separately, become unnecessary, and a manufacturing process can be simplified.

[Embodiment 4]
Of course, the capsule-like object in the present invention may be configured such that all the recesses communicate with the internal space of the capsule-like object, that is, all the recesses are communication holes. However, from the viewpoint of heat dissipation from the nanoparticle phosphor element to the sealing material, as described in the example shown in FIG. 4, the recess 4 a that communicates with the internal space of the capsule 4 and the internal space It is desirable to have two types of recesses that do not communicate with each other, that is, the recesses 4b (not including the coating layer). That is, the larger the area on the inner space side of the capsule-like material in contact with the medium in which the semiconductor nanoparticles are dispersed, the higher the effect of heat dissipation from the nanoparticle phosphor element to the sealing material. From the viewpoint of obtaining a higher heat dissipation effect, as in the example shown in FIGS. 1 and 2, there are two types of a recess 4 a that communicates with the internal space of the capsule 4 and a recess 4 b that does not communicate with the internal space. In particular, a configuration in which the concave portion communicating with the inner space is closed by the coating layer is preferable.

  The present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Hereinafter, the description of A / B indicates that A is coated with B.

[Example 1]
In Example 1, the nanoparticle core is CdSe, the shell layer is ZnS, the organic modifying group is dimethylaminoethanethiol (DAET), the medium is N, N, N-trimethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, Cytop having N, N-dimethyl-N-methyl-2- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (DEME-TFSI), the capsule is silica, and the coating layer is a fluoropolymer. (Semiconductor nanoparticle phosphor: CdSe / ZnS / DAET, nanoparticle phosphor element: semiconductor nanoparticle phosphor / DEME-TFSI / silica / Cytop).

(Production of nanoparticle phosphor element)
First, an octadecene (ODE) solution of a semiconductor nanoparticle phosphor having a nanoparticle core of CdSe, a shell layer of ZnS, and an organic modifying group of hexadecanethiol (HDT) was prepared. This semiconductor nanoparticle phosphor was subjected to organic modification group substitution treatment from HDT to DAET, and the semiconductor nanoparticle phosphor was transferred into a DEME-TFSI solvent.

Subsequently, a hollow sphere (capsule) made of silica having a plurality of concave portions on the surface and having an average particle diameter of 10 μm was prepared by publicly known literature (Takafumi Toyoda et al., “Fabrication Process of Silica Hard-shell Microcapsule (HSMC)). Separately prepared based on “Containing Phase-change Materials”, Chem. Lett. 2014, 43, 820-821). The later silica hollow spheres UV ozone treatment, to prepare a capsule form prepared by APRS treated by gas phase reaction with aminopropyltrimethoxysilane (APRS) and 90 ° C. in 3 hours in N ₂ nitrogen. This APrS-treated capsule and the semiconductor nanoparticle phosphor-containing DEME-TFSI were mixed and evacuated to inject the semiconductor nanoparticle phosphor-containing DEME-TFSI into the capsule. Then, 6% Cytop solution is dropped on the capsule, stirred and dried at 80 ° C. to block the portion communicating with the internal space of the recess 4a of the capsule, and finally heated at 80 ° C. for 1 hour. As a result, Cytop was polymerized. As described above, the SEM photograph of the produced nanoparticle phosphor element is shown in FIG. 3A, and it was confirmed that the capsule 4 having the coating layer 5 has a plurality of recesses on the surface.

(Production of light emitting element)
The nanoparticle phosphor element produced in the manner described above was mixed in an acrylic resin and dropped onto a blue LED chip, and the acrylic resin was cured to produce an LED light emitting element. This LED light-emitting element kept high efficiency for a long time by observation with time in a lighting test, that is, it had good quantum efficiency and good stability.

[Example 2]
A nanoparticle phosphor element and a light emitting element were produced in the same manner as in Example 1 except that the capsule 4 did not have the coating layer 5 (semiconductor nanoparticle phosphor: CdSe / ZnS / DAET, nanoparticle fluorescence). Body element: Semiconductor nanoparticle phosphor / DEME-TFSI / silica). As described above, the SEM photograph of the produced nanoparticle phosphor element is shown in FIG. 3C, and it was confirmed that the capsule 4 has a plurality of recesses on the surface. Similar to the light-emitting element of Example 1, the light-emitting element manufactured in Example 2 maintains high efficiency for a long time by observing the change over time in the lighting test, that is, has good quantum efficiency and good stability. Was.

[Example 3]
Silica-made hollow spheres (capsules) were processed with N-trimethoxysilylpropyl-N, N, N-trimethylammonium chloride (STMA) instead of APrS, and the coating layer was made of silica. A nanoparticle phosphor element and a light-emitting element were produced in the same manner as in Example 1 except that it was formed in (Semiconductor nanoparticle phosphor: CdSe / ZnS / DAET, Nanoparticle phosphor element: Semiconductor nanoparticle phosphor / DEME-TFSI / silica / silica).

  The STMA treatment of the capsule-like material was carried out by treating the capsule-like material with UV ozone, mixing with STMA in a 2-propanol solvent, and reacting at 80 ° C. for 5 hours. The coating layer made of silica was formed by mixing a capsule-like material into which semiconductor nanoparticle phosphor-containing DEME-TFSI was injected, an aqueous solution of ammonium bicarbonate and an aqueous solution of sodium silicate, and reacting at room temperature for 3 hours. Thus, in the present invention, not only a polymer but also an inorganic material such as silica can be used for the coating layer, and in that case, a higher coating effect can be expected than when the coating layer is formed of a polymer ( Lower gas permeability, lower moisture permeability) On the other hand, it becomes a rigid film, so the impact resistance is considered lower than when the coating layer is formed with a polymer (the polymer is soft and absorbs some impact) it can).

  Similar to the light-emitting device of Example 1, the light-emitting device manufactured in Example 3 also maintains high efficiency for a long time by observing changes over time in the lighting test, that is, having good quantum efficiency and good stability. Was.

[Example 4]
Nanoparticle fluorescence in the same manner as in Example 1 except that a resin containing a structural unit derived from an ionic liquid having a polymerizable functional group (a resin containing a structural unit derived from MOE-200T) was used as the medium. A body element and a light emitting element were produced (semiconductor nanoparticle phosphor: CdSe / ZnS / DAET, nanoparticle phosphor element: semiconductor nanoparticle phosphor / MOE-200T / silica / Cytop).

  In the capsule-like material in which a resin containing a structural unit derived from MOE-200T is encapsulated, first, a semiconductor nanoparticle phosphor is dispersed in MOE-200T in a solution state, and this is a hollow spherical product made of silica that has been treated with APrS. It was prepared by dropping on a (capsule-like material) and evacuating. Then, MOE-200T was polymerized by heating the capsule-like material at 80 ° C. to obtain a resin containing a structural unit derived from an ionic liquid.

  Similar to the light-emitting element of Example 1, the light-emitting element manufactured in Example 4 also maintains high efficiency for a long time by observing change with time in the lighting test, that is, having good quantum efficiency and good stability. Was. In this way, even when a resin containing a structural unit derived from an ionic liquid having a polymerizable functional group is used as a solid medium, the electrostatic interaction is similar to the case where the ionic liquid is used as a liquid medium. Thus, the stability of the semiconductor nanoparticle phosphor can be improved. In addition, since the medium is solid, the medium does not leak when the capsule is broken as in the case where the medium is liquid, and a nanoparticle phosphor element having excellent impact resistance is obtained. be able to.

[Example 5]
A nanoparticle phosphor element and a light emitting element were produced in the same manner as in Example 1 except that a capsule (polyamideimide) was produced using a polymer (polyamideimide) (semiconductor nanoparticle phosphor: CdSe / ZnS / DAET, nano Particle phosphor element: Semiconductor nanoparticle phosphor / DEME-TFSI / polyamideimide / Cytop).

  First, semiconductor nanoparticle phosphor-containing DEME-TFSI is mixed with a solution in which polyamideimide is dissolved, and then heated and stirred to form polyamideimide around the semiconductor nanoparticle phosphor-containing DEME-TFSI. Capsule-like materials were prepared using polyamideimide.

  Similar to the light-emitting device of Example 1, the light-emitting device manufactured in Example 5 also maintains high efficiency for a long time by observing change over time in the lighting test, that is, having good quantum efficiency and good stability. Was. By producing a capsule-like material using a polymer as in Example 5, the capsule-like material can be produced under milder conditions than an inorganic material such as silica, so that the semiconductor nano-particles dispersed in the medium can be produced. There is an advantage that the process damage to the particle phosphor is small. Moreover, since the capsule-like thing produced using a polymer is flexible compared with the capsule-like thing produced using inorganic materials, such as a silica, there also exists an advantage that it is hard to break.

[Example 6]
Example 6 shows a case where carboxydecanethiol (CDT) is used instead of DAET as the organic modification group in the semiconductor nanoparticle phosphor of Example 1 (nanoparticle phosphor: CdSe / ZnS / CDT, nanoparticle) Phosphor element: semiconductor nanoparticle phosphor / DEME-TFSI / silica / Cytop).

(Production of nanoparticle phosphor element)
An ODE solution of a semiconductor nanoparticle phosphor having a nanoparticle core of CdSe, a shell layer of ZnS, and an organic modifying group of hexadecanethiol (HDT) was prepared. The semiconductor nanoparticle phosphor was subjected to organic modification group substitution treatment from HDT to CDT, and then transferred to the DEME-TFSI medium. Subsequently, a nanoparticle phosphor element and a light emitting element were produced in the same manner as in Example 1.

  Similar to the light-emitting device of Example 1, the light-emitting device manufactured in Example 6 also maintains high efficiency for a long time by observing changes over time in a lighting test, that is, having good quantum efficiency and good stability. Was. As in Example 6, the organic modification group of the semiconductor nanoparticle phosphor may be other than the ionic organic modification group. In semiconductor nanoparticle phosphors, the synthesis conditions including the type contribute to characteristics such as quantum efficiency, emission peak wavelength, and emission line width. Since the number of ionic organic modifying groups is small, if there is a restriction that the organic modifying group is ionic, the degree of freedom in design in the production of semiconductor nanoparticle phosphors and, in turn, the production of nanoparticle phosphor elements is low. Therefore, it is difficult to produce a semiconductor nanoparticle phosphor having desired characteristics. As shown in Example 6, in the present invention, an organic modifying group other than an ionic organic modifying group can also be used, so that a semiconductor nanoparticle phosphor having desired characteristics can be easily produced. It is possible to design semiconductor nanoparticle phosphors and nanoparticle phosphor elements with a high degree of freedom.

[Example 7]
Example 6 shows a case where octadecene (ODE) is used as a medium in the nanoparticle phosphor element of Example 1 and the organic modification group of the semiconductor nanoparticle phosphor is hexadecanethiol (HDT) (nanoparticle phosphor) : CdSe / ZnS / HDT, nanoparticle phosphor element: semiconductor nanoparticle phosphor / ODE / silica / Cytop).

  Specifically, CdSe / ZnS / HDT-containing ODE was subjected to the same procedure as in Example 1 except that it was encapsulated in a hollow sphere (capsule) made of silica without performing an organic modifying group substitution treatment or the like. A nanoparticle phosphor element and a light emitting element were produced.

  Similar to the light-emitting device of Example 1, the light-emitting device manufactured in Example 7 also maintains high efficiency for a long time by observing changes over time in a lighting test, that is, having good quantum efficiency and good stability. Was. As in Example 7, in the present invention, a liquid other than an ionic liquid can be used as the liquid medium. In that case, it is difficult to volatilize under normal use conditions (such as LED). It is preferable to use a medium with a high boiling point (for example, a boiling point of 200 ° C. or higher) from the viewpoint that a decrease in the amount of the medium due to volatilization or capsule breakage due to vapor pressure hardly occurs and a highly stable light-emitting element can be obtained. Thus, by selecting an appropriate combination of the medium and the organic modifying group, the semiconductor nanoparticle phosphor and the nanoparticle fluorescence can be produced with a high degree of freedom so that a semiconductor nanoparticle phosphor having desired characteristics can be easily produced. It is possible to design body elements.

[Example 8]
First light emitting layer (semiconductor nanoparticle phosphor (red light emission) / DEME-TFSI / silica / Cytop / acrylic resin) and second light emitting layer (semiconductor nanoparticle phosphor (green light emission) / DEME) shown in FIG. -TFSI / silica / cytop / acrylic resin) was manufactured. The nanoparticle phosphor element was produced in the same manner as in Example 1 (CdSe / ZnS / DAET / DEME-TFSI / silica / Cytop). The produced nanoparticle phosphor element had an emission peak wavelength in the red region. Similarly, a nanoparticle phosphor element having an emission peak wavelength in the green region was produced. The particle size was red-emitting semiconductor nanoparticle phosphor> green-emitting semiconductor nanoparticle phosphor, and red-emitting nanoparticle phosphor element> green-emitting nanoparticle phosphor element.

  A solution of these two types of nanoparticle phosphor elements was mixed in an acrylic resin material and dropped onto the LED chip, and then a heat curing treatment was performed. As a result, the red light-emitting nanoparticle phosphor element having a large particle size during heat-curing settles after a predetermined time, and the first light-emitting layer mainly including the red light-emitting nanoparticle phosphor element, A light emitting device having a two-layer structure including a second light emitting layer including a green light emitting nanoparticle phosphor device was produced. Thus, when nanoparticle phosphor elements having different particle sizes are used, a light-emitting element having a two-layer structure as shown in FIG. 5 is manufactured by a simple process in which both are mixed and allowed to stand. This eliminates the need for complicated processes such as forming a green light emitting layer and a red light emitting layer separately. As described above, in such a light-emitting element, energy re-absorption from the second light-emitting layer, which is a green light-emitting layer, to the first light-emitting layer, which is a red light-emitting layer, is unlikely to occur.

  DESCRIPTION OF SYMBOLS 1 Nanoparticle fluorescent substance device, 2 Semiconductor nanoparticle fluorescent substance, 3 Medium, 4 Capsule-like thing, 4a, 4b Recessed part, 5 Coating layer, 6 Positive charge, 7 Negative charge, 8 Organic modification group, 11 Light emitting element, 12 Light source , 13 Sealing material, L1 excitation light, L2 fluorescence, T heat, 21 nanoparticle phosphor element, 41 light emitting element, 42 first light emitting layer, 43 second light emitting layer, 44 nanoparticle phosphor element, 45 semiconductor nanoparticle Phosphor, 46 Medium, 47 Capsule, 47a, 47b Recess, 48 Coating layer, 49 Encapsulant, 51 Nanoparticle phosphor element, 52 Semiconductor nanoparticle phosphor, 53 Medium, 54 Capsule, 54a, 54b Recess, 55 coating layer, 56 sealing material.

Claims (7)

A capsule having a plurality of recesses on the surface;
A medium enclosed in the capsule,
A nanoparticle phosphor element comprising a semiconductor nanoparticle phosphor dispersed in the medium.   The nanoparticle phosphor element according to claim 1, wherein the capsule is composed of at least two layers.   The nanoparticle phosphor element according to claim 1 or 2, wherein the medium is a liquid.   The nanoparticle phosphor element according to claim 3, wherein the medium is an ionic liquid.   The nanoparticle phosphor element according to claim 1 or 2, wherein the medium is a solid.   The nanoparticle phosphor element according to claim 5, wherein the medium is a resin including a structural unit derived from an ionic liquid having a polymerizable functional group. A sealing material;
A light emitting device comprising the nanoparticle phosphor device according to any one of claims 1 to 6, dispersed in the sealing material.