JP2007022945A - Light-emitting substance and light-emitting composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zinc-containing light-emitting body of a nano-meter size and a light-emitting composition exhibiting excellent transparency. <P>SOLUTION: The light-emitting substance comprises a zinc ion as a luminescence center where the zinc ion is adjacent to a different kind of metal element via oxygen. The light-emitting composition comprises the light-emitting body dispersed in a liquid phase or a solid phase. Preferably, the diameter of the dispersed light-emitting body is 1-50 nm. Preferably, the molar ratio M/Zn of the metal element M adjacent to zinc to zinc is 1-4. Preferably, the metal element is one or more elements selected from among group IVa, Va, VIa and IIIb elements. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a luminous body containing zinc that emits light by energy incident from the outside, and a luminous composition containing the luminous body. Furthermore, it is related with the light-emitting body used for optical function application fields, such as a display and LED, and the luminescent composition containing these light-emitting bodies.

  As a luminous body (phosphor), a material in which a rare earth element or a transition metal is added to an inorganic base material has been known for a long time (Non-Patent Document 1), and is used in various displays such as CRT and PDP and fluorescent lamps. Yes. On the other hand, many compounds containing zinc, which is an inexpensive element with a large reserve, have been studied, and zinc sulfide has long been known as a light emitter (Non-Patent Document 1, Patent Document 1). In addition, research on organic EL devices using light emission of zinc-containing organic complexes has been reported, and it has been reported that high efficiency can be achieved by making them particularly nano-sized (Patent Documents 2 and 3).

Zinc oxide, on the other hand, is more stable than zinc sulfide, and theoretically has excitonic ultraviolet emission characteristics. However, it is difficult to obtain stable light emission characteristics because the zinc oxide fine particles utilize light emission due to defects caused by oxygen deficiency. In order to solve such a problem, it has been disclosed that light emission at room temperature around 375 nm can be stably obtained by setting the nitrogen concentration in the crystal to 10 ¹⁶ cm ⁻³ 10 ²⁰ cm ⁻³ and the particle diameter to 50 nm to 200 nm. (Patent Document 4).

Recently, blue light emitting diodes using pn bonds of zinc oxide and various light emitting materials using zinc oxide nanoparticles have been reported.
Japanese Patent Laid-Open No. 52-30450 JP 2005-82684 A JP 2005-68326 A Japanese Patent Laid-Open No. 2005-60145 Fluorescent Material Society, Fluorescent Handbook, Ohmsha

  As described above, various light-emitting materials containing rare earth elements, transition metals, zinc, and the like are known, but most of them are inorganic materials, which can sufficiently cope with the recent plasticization of functional optical materials. Absent. That is, it is difficult to add a conventional light emitting material such as zinc sulfide into an organic material without impairing optical properties such as transparency of the base material.

  On the other hand, in order to use zinc oxide as a light emitting material, it is difficult to obtain stable light emission characteristics because light emission due to defects caused by oxygen deficiency is used. On the other hand, the nitrogen doping described in Patent Document 4 requires a vacuum process and is difficult to manufacture at a low cost. Similarly to the zinc sulfide described above, it is possible to form a light emitting material or to form a base material by a simple method such as coating film formation. It is difficult to add to an organic material without impairing optical properties such as transparency.

  In addition, the emission wavelength of zinc oxide is limited to around 375 nm, and its application as a fluorescent material is limited. This invention is made | formed in view of the above situations, and it is providing the light-emitting body and luminescent composition which can be formed with a simple method using cheap elements, such as zinc.

  The inventors of the present application have made extensive studies in order to achieve the above object. As a result, it has been found that an illuminant having zinc ions as an emission center and zinc ions adjacent to a dissimilar metal element through oxygen is effective as a blue illuminant as well as ultraviolet light emission. It has been found that the body can be doped at a high concentration in the liquid phase or in the solid phase and quenching due to energy transfer between zinc ions and CH groups or OH groups can be suppressed.

  In addition, the inventors discovered that the optical transparency of the dispersion medium can be ensured by controlling the diameter of the luminescent material in which zinc ions are adjacent to the dissimilar metal element via oxygen, and the present invention has been completed.

  In order to solve the above-described problem, the light emitter according to claim 1 is a light emitter characterized in that zinc ions are used as a light emission center and the zinc ions are adjacent to a dissimilar metal element through oxygen. .

  The luminous body according to claim 2 is a luminous body characterized in that a molar ratio M / Zn between the metallic element M adjacent to zinc and the zinc is 1 to 4.

  The phosphor according to claim 3 is characterized in that the metal element adjacent to zinc is one or more elements selected from group IVa, Va, VIa, and IIIb. is there.

  In the phosphor of the present invention, the zinc ion is adjacent to the dissimilar metal element through oxygen and is schematically shown in FIGS. 1 and 2 (depending on the coordination number of the coordination metal). As shown in the figure, the phosphor is formed of zinc ions (1) formed by coordination of a different element (2) via oxygen, and has a functional group R having organic characteristics on the outermost part. .

  Here, what is important is to reduce the abundance ratio of zinc ions to adjacent positions via oxygen as much as possible. Therefore, the number and species of ligands composed of oxygen and other metal species are not fixed, and are not strictly limited to the molecular structure as shown in FIGS. 1 and 2 in terms of stoichiometry. In order to exhibit the effect effectively, the molar ratio M / Zn of the metal element M adjacent to zinc is preferably 1 to 4. When it is smaller than 1, sufficient effect of quenching suppression is not exhibited. The disposition of the different elements around the zinc ions for expressing the desired effect is sufficient by 4 mole times, and even if the number is more than that, improvement of the effect cannot be expected.

  Although the heterogeneous element adjacent through oxygen is not particularly limited, it is preferably one or two or more elements selected from group IVa, Va, VIa, and IIIb. More preferable are Al, Ga, In, Ti, Zr, V, Nb, Ta, Mo, and W.

  According to said structure, although the detailed mechanism is not clear, light emission from ultraviolet to visible light is attained. Furthermore, quenching due to proximity interaction and / or cluster formation is suppressed by the effect of different elements existing between zinc atoms.

  The luminescent composition according to claim 4 is a luminescent composition in which the phosphor is dispersed in a liquid phase or a solid phase.

  The luminescent composition according to claim 5 is a luminescent composition characterized in that the diameter of the luminescent material to be dispersed is 150 nm.

  The luminescent composition according to claim 6 is characterized in that the dispersion medium of the luminescent material is an organic substance or an organic-inorganic hybrid.

  When the luminescent composition according to the present invention is used for an optical material or the like, it is desirable to have optical transparency (transmittance). The transmittance of the organic polymer is not particularly limited as long as it has a permeability. However, the transmittance is preferably 30100%, and more preferably 80100%. In addition, the phosphor of the present invention has an average diameter of 150 nm, and can have an association structure as long as the presence of zinc atoms can be reduced as much as possible at an adjacent position via oxygen. . Here, R in FIGS. 1 and 2 is an alkylcarbonyl group such as an alkyl group or an acetyl group, hydrogen or the like.

  As described above, the luminous body of the present invention has zinc ions as the emission center, and the zinc ions are adjacent to the dissimilar metal element through oxygen, and the luminous body is in a liquid phase or a solid phase. A luminescent composition can be formed by dispersing. As a result, it is possible to provide a light emitting composition satisfying suppression of quenching and ensuring optical transparency.

  The illuminant of the present invention is preferably used in, for example, an optical function application field that emits light by being excited by energy such as incident light. This is a light emitter. The luminescent composition is a luminescent composition in which the phosphor is dispersed in a liquid phase or a solid phase.

  The phosphor of the present invention has zinc ions as the emission center, and the zinc ions are adjacent to the dissimilar metal element through oxygen. A method for forming a light emitter in which other metal species are coordinated to zinc via oxygen is not particularly limited. For example, it is formed by a reaction between a zinc metal salt and a metal alkoxide.

  Other metal species that coordinate to zinc metal via oxygen are elements that can be coordinated to rare earth metal via oxygen, and are not particularly limited as long as they do not adversely affect the intended properties. Group 4, 4A, 5A, and 6A metals are used. More preferably, aluminum, gallium, titanium, zirconium, niobium, or tantalum is used.

  The method for forming the light emitter is not particularly limited as long as the metal coordination via oxygen to the target dilute zinc can be formed. For example, after mixing a zinc metal raw material and a coordinating metal raw material, a heat treatment and pulverization method (starting raw materials include metal salts, hydroxides, oxides, etc.), zinc metal salt and coordination There are a method in which a possible metal salt is dissolved in a solvent, followed by precipitation by hydrolysis, a method in which a zinc metal salt and a metal alkoxide capable of coordination are reacted in an organic solvent.

  In order to obtain a nanometer-sized light emitter, a method of reacting a metal alkoxide capable of coordination with a zinc metal salt in an organic solvent is preferably used. The solvent to be used is not particularly limited, and any solvent may be used as long as the final product having a coordination structure can be dispersed in the organic polymer. Examples of such solvents include primary alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and t-butanol; polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin. ; Glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, propylene glycol-α-monomethyl ether, propylene glycol-α-monoethyl ether; ketones such as acetone and methyl ethyl ketone; tetrahydrofuran, dioxane and the like Cyclic ethers of; esters such as methyl acetate, ethyl acetate, propyl acetate; aromatic compounds such as acetonitrile, benzene, toluene, xylene Pentane, hexane, heptane, hydrocarbon compounds such as cyclohexane; and the like are used.

  In order to form the phosphor, it is possible to use a method of heating to the reflux temperature of the solvent, and this method is effective because it can accelerate the reaction rate in many cases. It is also possible to control the size of the luminescent material by adding water to the obtained coordination product and hydrolyzing it.

  As starting materials for zinc metal, mineral acid salts such as nitrates, sulfates, carbonates and chlorides, organic acid salts such as formates, acetates and oxalates, alkoxides and the like are used. Considering the reduction of anionic impurities, it is preferable to use organic acid salts such as formate, acetate and oxalate and alkoxides. More preferably, zinc acetate is used. Zinc acetate usually contains crystal water and can be used as it is depending on the type of metal to be coordinated, but it is preferable to perform a dehydration treatment before the reaction.

  The functional group R of the dispersed phase shown in FIG. 1 is not particularly limited and is selected depending on the type of organic polymer to be combined. In order to improve the compatibility with the organic polymer, it can be selected for the purpose of imparting polymerizability with the organic polymer or a monomer component capable of forming the organic polymer. For example, as R, hydrogen, an alkyl group, a reactive vinyl group, an allyl group, a diazo group, a nitro group, a cinnamoyl group, an acryloyl group, an imide group, an epoxy group, a cyano group, or an alkyl group containing these functional groups , Alkylsilyl groups, alkylcarbonyl groups, and the like.

  In addition, if it can be homogeneously combined with the dispersion medium, it contains active hydrogen such as carboxylate groups, hydroxyl groups, amino groups, amide groups such as poly (meth) acrylic acid, polyethylene glycol, polyethylene oxide, and celluloses. A polymer having a functional group can also be used.

  Examples of the method for introducing the functional group R into the luminescent material include (1) a method of introducing the luminescent material by a reaction after forming the luminescent material, or (2) an alkoxide as a starting material that can be coordinated to zinc metal in advance through oxygen. There is a method of reacting with a zinc metal salt after introducing an R group into.

The compound to be reacted with the luminescent material is not particularly limited as long as it can form the above-mentioned target structure, but as the method of (1), a compound having an active hydrogen such as a carboxylate group, a hydroxyl group, an amino group or an amide group at the terminal The method (2) includes alkyl groups, reactive vinyl groups, allyl groups, diazo groups, nitro groups, cinnamoyl groups, acryloyl groups, imide groups, epoxy groups, cyano groups, or alkyls containing these functional groups. Group-containing alkoxysilane (R ¹ R ² R ³ SiOR ⁴ : R ¹ is alkyl group, reactive vinyl group, allyl group, diazo group, nitro group, cinnamoyl group, acryloyl group, imide group, epoxy group, cyano group group or an alkyl group containing these functional groups, R ^2, R ³ is an alkyl group, a vinyl group having reactivity, allyl group, diazo group, two B group, a cinnamoyl group, an acryloyl group, an imido group, an epoxy group, an alkyl group containing a cyano group or the functional group, an alkoxyl group, ^{R 4} is an alkyl group), alkoxy germanium ^{(R 1 R 2 R 3 GeOR} 4 R ¹ is an alkyl group, a reactive vinyl group, an allyl group, a diazo group, a nitro group, a cinnamoyl group, an acryloyl group, an imide group, an epoxy group, a cyano group, or an alkyl group containing these functional groups, R ² , R ³ is an alkyl group, a reactive vinyl group, an allyl group, a diazo group, a nitro group, a cinnamoyl group, an acryloyl group, an imide group, an epoxy group, a cyano group, or an alkyl group containing these functional groups, an alkoxyl group R ⁴ is preferably a compound capable of reacting with the luminescent material by condensation polymerization such as an alkyl group.

  The luminescent composition by dispersing the luminescent material in the medium is, for example, mixed and dispersed with the luminescent material formed by the reaction of the metal alkoxide and the rare earth metal salt / and the fourth period transition metal salt and the dispersion layer. Can be adjusted. The medium in which the illuminant is dispersed is selected according to the purpose, and is not limited to a liquid phase or a solid phase, an inorganic phase, an organic phase, or the like.

  Hereinafter, the case where an organic phase is used as a medium will be described. There is no particular limitation as long as it can disperse the zinc metal coordinated with other metal species without agglomeration, but it is preferably substantially transparent in the wavelength band in which the expression of the optical function is utilized. What has the property is used. Here, the wavelength band in which the manifestation of the optical function is used is not limited to the purple-red visible band, but is shorter than ultraviolet light or X-rays having a wavelength shorter than that of purple having a wavelength of about 400 nm, and red having a wavelength of about 750 nm. Alternatively, an infrared band having a long wavelength may be used. Examples of such an organic polymer include polymethyl methacrylate, polycyclohexyl methacrylate, polybenzyl methacrylate, polyphenyl methacrylate, polycarbonate, polyethylene terephthalate, polystyrene, polytetrafluoroethylene, poly-4-methylpentene 1, polyvinyl alcohol, polyethylene, Examples include polyacrylonitrile, styrene acrylonitrile copolymer, polyvinyl chloride, polyvinyl carbazole, styrene maleic anhydride copolymer, polyolefin, polyimide, epoxy resin, polysiloxane, polysilsesquioxane, polysilane, polyamide, and cyclic olefin resin. However, it is not limited to these. Moreover, these organic polymers may be used independently and can also be used in combination of 2 or more type. In addition, these organic polymers dissolved in a solvent or melted by heating or the like can be processed into a desired light-emitting composition, but monomers, oligomers, monomers and oligomers that are precursors of organic polymers Polymerization can also be performed in the process of processing the mixture with the organic polymer into the form of the desired light emitting composition using the starting material as a starting material. Furthermore, these organic polymers may have a functional group that promotes a reaction such as addition, crosslinking, or polymerization by light or heat in the main chain or side chain. Examples of such a functional group include a hydroxyl group, a carbonyl group, a carboxyl group, a diazo group, a nitro group, a cinnamoyl group, an acryloyl group, an imide group, and an epoxy group. The organic polymer may contain additives such as stabilizers such as plasticizers and antioxidants, surfactants, dissolution accelerators, polymerization inhibitors, and colorants such as dyes and pigments, and catalysts. Furthermore, in order to improve molding processability such as coating properties, organic polymers are made of organic solvents such as solvents (water, alcohols, glycols, cellosolves, ketones, esters, ethers, amides, hydrocarbons). Solvent).

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[Examples 1 to 8]
Transparent solution by adding zinc acetate dehydrated at 110 ° C for 1 hour to 1-methoxy-2-propanol and metal alkoxide (ZnO and a total concentration of 5% by weight of oxide equivalent in metal alkoxide) and heat-treating it. Got. The particle size of the obtained reaction product was measured by a dynamic scattering method. Table 1 summarizes the types of coordination metals, the ratio of coordination metals, reaction conditions, and particle sizes.

Example 9
Zinc acetate dehydrated at 110 ° C. for 1 hour and metal alkoxide (ZnO and a total concentration of 5% by weight of oxide equivalents in the metal alkoxide) were added to 2-butanol and heat-treated at 80 ° C. for 24 hours. Methoxy-2-propanol was added. After 2-butanol was distilled off under reduced pressure, a transparent solution was obtained by further heat treatment at 80 ° C. for 1 hour.

  The obtained phosphor solution was confirmed to emit ultraviolet and blue light by excitation light of 280 and 380 nm taken out by a filter using a xenon lamp. The fluorescence spectra of Example 2 (FIGS. 3 and 4) and Example 9 (FIGS. 5 and 6) are shown as representative examples.

Example 10
To the ZnAl-containing phosphor prepared in Example 9, methacrylic acid twice as much as Al was added and stirred at room temperature for 2 hours, and then the solvent was removed under reduced pressure at a temperature of 40 ° C. or lower to leave a colorless and transparent syrup-like residue. I got a review. After adding methyl methacrylate to the colorless transparent residue to make a transparent solution again, pentaerythritol tetraacrylate and Irgacure 149 are added (methyl methacrylate / pentaerythritol tetraacrylate: 90/10 by weight, Irgacure 149 is acrylic. A transparent organic-inorganic composite solid containing 5 wt% Zn was obtained by irradiating a high-pressure mercury lamp in a glass container having a diameter of 5 mm and a diameter of 5 mm. Blue light emission was observed by irradiating excitation light having wavelengths of 280 and 380 nm to the Eu-containing organic-inorganic composite thus obtained.

[Comparative example]
Although the solubility of various zinc metal salts and oxides in an organic solvent and the dispersibility in an organic polymer were verified, a transparent solution or a transparent dispersion could not be obtained.

  The present invention relates to a light-emitting body and a light-emitting multi-body composition particularly preferably used in an optical function application field that emits light when excited by energy such as incident light.

It is a schematic diagram of a light-emitting body. It is a schematic diagram of a light-emitting body. It is an emission spectrum of Example 2 (excitation at 280 nm). 2 is an emission spectrum of Example 2 (excitation at 380 nm). It is the emission spectrum (280 nm excitation) of Example 9. It is an emission spectrum (excitation of 380 nm) of Example 9.

Claims (6)

An illuminant having a zinc ion as an emission center, wherein the zinc ion is adjacent to a dissimilar metal element through oxygen. The light emitting body according to claim 1, wherein a molar ratio M / Zn of the metal element M adjacent to zinc and the zinc is 1 to 4. 3. The light-emitting body according to claim 1, wherein the metal element is one or more elements selected from group IVa, Va, VIa, and IIIb. A luminescent composition comprising the phosphor according to any one of claims 1 to 3 dispersed in a liquid phase or a solid phase. The luminescent composition according to claim 4, wherein a diameter of the luminescent material to be dispersed is 150 nm. 6. The luminescent composition according to claim 4, wherein the dispersion medium is an organic substance or an organic-inorganic hybrid.