JP2006004744A - Dye-sensitized photoelectric cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitized photocell in which a sensitized dye does not fall off from a metal oxide semiconductor particle and in which reduction of photo-electric energy exchange efficiency does not occur. <P>SOLUTION: This is the dye-sensitized cell using a dye containing micro-capsulized metal oxide semiconductor particle 3 which is micro-capsulized by covering the metal oxide semiconductor particles 31 by an organic polymer compound 32, and contains the dye 33 in a micro-capsulized covered film of the organic polymer compound 32. The dye containing micro-capsulized metal oxide semiconductor particles 3 can be obtained for example, by means that the metal oxide semiconductor particles 31 are made to form ad-micelle while using a polymerizable surfactant as the nuclear material, to contain the dye in the ad-micelle, and to carry out polymerization reaction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a dye-sensitized photocell, and more particularly to a dye-sensitized photocell that does not cause a decrease in photo-electric energy exchange efficiency.

  In general, single-crystal silicon solar cells, amorphous silicon solar cells, compound semiconductor solar cells, etc. are known as photovoltaic cells (also referred to as solar cells), but it is difficult to suppress manufacturing costs and raw material costs, which hinders the spread of solar cells. It was. Under such circumstances, it is disclosed that a dye-sensitized photovoltaic cell using an electrode constituted by supporting a dye on the surface of a semiconductor layer has characteristics of low cost and high conversion efficiency (for example, Patent Document 1 and Patent). Reference 2). In addition, as a dye-sensitized photovoltaic cell, a battery using porous metal oxide semiconductor particles adsorbed with a dye is also disclosed (see, for example, Patent Document 3 and Patent Document 4).

  The general basic structure of a dye-sensitized photovoltaic cell is that a porous metal oxide semiconductor with a dye adsorbed is formed on a transparent conductive substrate, and the vacancies in the metal oxide semiconductor layer are filled with a charge transport layer. The charge transport layer has a structure in contact with the conductive film that becomes the counter electrode and / or the conductive film that becomes the catalyst.

  The operation principle of the dye-sensitized solar cell is as follows. Light incident from the transparent conductive substrate side is absorbed by the dye supported on the surface of the metal oxide semiconductor through the transparent conductive film and the metal oxide semiconductor, and the sensitizing dye that has absorbed the light is excited. The excited dye quickly passes electrons to the metal oxide semiconductor, and the electrons travel through the metal oxide semiconductor and flow to the transparent conductive film. After emitting electrons, the positively charged dye returns to neutral by receiving electrons from the charge transport layer.

  A porous metal oxide semiconductor is generally formed by applying a metal oxide sol generated by a sol-gel method using a metal halide or metal alkoxide as a raw material to a base material, followed by firing at about 400 to 500 ° C. It is formed in a form in which physical semiconductor fine particles are laminated.

Japanese Patent No. 2664194 Japanese Patent No. 2101079 JP 2003-197282 A JP-A-10-255863

However, those described in Patent Documents 3 and 4 are those in which a sensitizing dye is simply adsorbed or supported on metal oxide semiconductor particles. In such a state that the sensitizing dye is simply adsorbed or supported on the metal oxide semiconductor particles, the dye can be easily removed from the semiconductor particles during the handling of the dye-adsorbing semiconductor particles, such as in the process of making a dye-sensitized photocell. Occasionally, the light-electric energy exchange efficiency may be reduced.
The present invention overcomes the above-mentioned problems of the prior art and provides a dye-sensitized photovoltaic cell in which the sensitizing dye does not fall off from the metal oxide semiconductor particles and the efficiency of photo-electric energy exchange does not decrease. To do.

As a result of intensive studies, the present inventor has achieved the above object by adopting the following configuration, and has achieved the present invention.
That is, the present invention is as follows.
(1) A dye-containing microencapsulated metal oxide semiconductor that is microencapsulated by coating metal oxide semiconductor particles with an organic polymer compound and includes a dye in the microencapsulated coating film of the organic polymer compound Dye-sensitized photocell using particles.
(2) The dye-containing microencapsulated metal oxide semiconductor particles form an admicelle using a polymerizable surfactant as a core substance and a polymerization reaction after the dye is included in the admicelle. The dye-sensitized photocell of (1) above,

(3) The dye-sensitized photocell of the above (2), which is polymerized with another comonomer.
(4) The dye-sensitized photovoltaic cell according to (1) or (2), wherein the metal oxide semiconductor is titanium oxide.
(5) The dye-sensitized photovoltaic cell according to (2), wherein colloidal titanium oxide is used in the preparation of the dye-containing microencapsulated metal oxide semiconductor particles.
(6) The dye-sensitized photovoltaic cell according to (2), wherein a dye having a polymerizable reactive group is used in the preparation of the dye-containing microencapsulated metal oxide semiconductor particles.

(7) The dye is at least selected from organic metal complex dyes, pyridine dyes, phthalocyanine dyes, porphyrin dyes, cyanine dyes, merocyanine dyes, coumarin dyes, polymethine dyes, mercurochrome dyes, and eosin dyes. The dye-sensitized photocell of (1), (2) or (6) which is any one of the above.
(8) The dye-sensitized photovoltaic cell according to (2), wherein the polymerizable surfactant is at least one selected from an anionic polymerizable surfactant, a cationic polymerizable surfactant, and a nonionic polymerizable surfactant. .

  The dye-sensitized photovoltaic cell of the present invention is obtained by microencapsulating metal oxide semiconductor particles with an organic polymer compound and including the dye in the organic polymer compound constituting the encapsulated wall material. It was possible to prevent a decrease in photo-electric energy exchange efficiency without dropping from the metal oxide semiconductor particles.

  FIG. 2 shows a conceptual diagram of the dye-containing microencapsulated metal oxide semiconductor particles used in the dye-sensitized photovoltaic cell of the present invention. The dye-containing microencapsulated metal oxide semiconductor particle 3 shown in FIG. 2 is microencapsulated by coating the metal oxide semiconductor particle 31 with an organic polymer compound 32 and forms an encapsulated wall material. The dye 33 is included in the compound.

Although it does not specifically limit as a metal oxide semiconductor particle used for the dye-sensitized photovoltaic cell of this invention, The metal oxide which shows the property of an n-type semiconductor can be used. Specific examples include oxides of zinc, niobium, tin, titanium, vanadium, indium, tungsten, tantalum, zirconium, molybdenum, and manganese. In addition, perovskites such as SrTiO ₃ , CaTiO ₃ , BaTiO ₃ , MgTiO ₃ , SrNb ₂ O ₆ , or complex oxides or oxide mixtures thereof can also be used. Among these, titanium oxide is preferable.
In preparing the dye-containing microencapsulated metal oxide semiconductor particles in the dye-sensitized photovoltaic cell of the present invention, it is preferable to use colloidal titanium oxide. Although it does not specifically limit as colloidal titanium oxide, The thing as described in Unexamined-Japanese-Patent No. 2003-95657, Unexamined-Japanese-Patent No. 2003-192348, Unexamined-Japanese-Patent No. 2002-145614, and Unexamined-Japanese-Patent No. 2002-356320 is used suitably.

The dye used in the dye-sensitized photovoltaic cell of the present invention is not particularly limited, but an organometallic complex dye, a pyridine dye, a phthalocyanine dye, a porphyrin dye, a cyanine dye, a merocyanine dye, a coumarin dye, and a polymethine dye. Examples thereof include dyes, mercurochrome dyes, eosin dyes, etc., and these may be used alone or in combination of two or more.
Although it does not specifically limit as an organometallic complex pigment | dye, The thing as described in the international publication 96/00247 pamphlet is mentioned.

The dye-containing microencapsulated metal oxide semiconductor particles used in the dye-sensitized photovoltaic cell of the present invention are microencapsulated by coating the metal oxide semiconductor particles with an organic polymer compound and constitute an encapsulated wall material. A pigment is included in the organic polymer compound.
The method for producing the dye-containing microencapsulated metal oxide semiconductor particles is not particularly limited, but an admicelle is formed using a metal oxide semiconductor particle as a core substance and a polymerizable surfactant, and the dye is contained in the admicelle. The polymerization reaction is preferably carried out after inclusion.

  Specifically, an aqueous dispersion is prepared by dispersing metal oxide semiconductor particles in an aqueous solvent in advance, and at least a polymerizable surfactant and a dye are added to the aqueous dispersion, and the polymerizable surfactant is used. It can be suitably produced by forming an admicelle, including a dye in the admicelle, and adding a polymerization initiator or the like as necessary to cause a polymerization reaction. Depending on the form of the desired dye-containing microencapsulated metal oxide semiconductor particles, in addition to the polymerizable surfactant, another comonomer may be added and copolymerized with the polymerizable surfactant. The metal oxide semiconductor particles used here may be those having a hydrophilic group added to the surface by surface treatment.

More specifically, for example, an anionic polymerizable surfactant and a dye are added to an aqueous dispersion in which metal oxide semiconductor particles are dispersed to cause a polymerization reaction.
Examples of other comonomers to be added in addition to the anionic polymerizable surfactant include hydrophilic monomers having an anionic group and hydrophobic monomers.

In particular, in the case of metal oxide semiconductor particles having an anionic group on the surface, a cationic polymerizable surfactant, an anionic polymerizable surfactant, and an aqueous dispersion in which the metal oxide semiconductor particles are dispersed. The dye-containing microencapsulated metal oxide semiconductor particles according to the present invention can be obtained by adding a dye and performing a polymerization reaction. In addition to the cationic polymerizable surfactant, the anionic polymerizable surfactant and the dye, other comonomers such as a hydrophilic monomer and a hydrophobic monomer having an anionic group are added to the cationic polymerizable interface. You may make it copolymerize with an activator, anionic polymerizable surfactant, etc.
Here, the anionic polymerizable surfactant is a surfactant having an anionic group, a hydrophobic group and a polymerizable group, and the cationic polymerizable surfactant is a cationic group and a hydrophobic group. It is a surfactant having a group and a polymerizable group.

Such a dye-containing microencapsulated metal oxide semiconductor particle includes a cationic polymerizable surfactant in which a metal oxide semiconductor particle having an anionic group on the surface has a cationic group, a hydrophobic group, and a polymerizable group. And an anionic polymerizable surfactant having an anionic group, a hydrophobic group and a polymerizable group, and an organic polymer compound having a repeating structural unit derived from another comonomer, and a dye is included. ing.
In order to produce the dye-containing microencapsulated metal oxide semiconductor particles, the cationic polymerizable surfactant is added to and mixed with the aqueous dispersion of the metal oxide semiconductor particles having the anionic group on the surface, Other comonomers, such as a hydrophobic monomer and an anionic polymerizable surfactant, can be added to emulsify, and a polymerization initiator can be added to perform emulsion polymerization.

According to such an emulsion polymerization method, first, an anionic group on the surface of a metal oxide semiconductor particle having an anionic group on its surface and a cationic group of a cationic polymerizable surfactant are ionically bonded, Forms a structure in which the hydrophobic group of the cationic polymerizable surfactant and the hydrophobic group of the anionic polymerizable surfactant face each other, and the anionic group of the anionic polymerizable surfactant is oriented toward the aqueous phase. To do. When the polymerization reaction is performed in this state, an organic polymer compound layer maintaining the above structure is formed on the surface of the metal oxide semiconductor particles. That is, the arrangement form of the cationic polymerizable surfactant and the anionic polymerizable surfactant existing around the metal oxide semiconductor particles before the polymerization reaction is extremely highly controlled, and toward the aqueous phase at the outermost layer. A state in which the anionic group is oriented is formed. Then, by the emulsion polymerization reaction, the cationic polymerizable surfactant and the anionic polymerizable surfactant are converted into the organic polymer compound in this highly controlled form. Therefore, the structure of the microencapsulated pigment of the present invention is controlled with extremely high accuracy.
The dye-containing microencapsulated metal oxide semiconductor particles according to the present invention are coated with a polymer prepared in advance on the metal oxide semiconductor particles by using a phase inversion emulsification method or an acid precipitation method. It may be a thing.

  Here, the dye-containing microencapsulated metal oxide semiconductor particles according to the present invention have an aspect ratio (long / short) of 1.0 to 1.3 and a Zingg index of 1.0 to 1.3 ( More preferably, it is 1.0 to 1.2). As a result, when a metal oxide semiconductor is formed on a transparent conductive substrate in the production of a dye-sensitized photovoltaic cell described in detail later, the arrangement state of the metal oxide semiconductor particles is improved, and more metal oxides are formed. Semiconductor particles can be applied, and as a result, a dye-sensitized photocell with higher conversion efficiency can be obtained.

When the short diameter of a particle is b, the long diameter is l, and the thickness is t (l ≧ b ≧ t> 0), the aspect ratio (long / shortness) is 1 / b (≧ 1), and the flatness is b / t ( ≧ 1) and Zingg index = long / short / flatness = (l · t) / b ² . That is, the true sphere has an aspect ratio of 1 and a Zingg index of 1.
If the Zingg index is larger than 1.3, the dye-encapsulated microencapsulated metal oxide semiconductor particles become flatter and have less isotropy. It becomes a tendency not to become. The method for setting the aspect ratio and the Zingg index within the above ranges is not particularly limited, but the dye-containing microencapsulated metal oxide semiconductor particles coated with an organic polymer compound by the emulsion polymerization method described above can easily satisfy these conditions. Can satisfy.

  When the dye-containing microencapsulated metal oxide semiconductor particles are in the above-described aspect ratio and Zingg index range, a true spherical shape is obtained. When the pigment-containing microencapsulated metal oxide semiconductor particles are spherical, when the coating liquid containing the pigment-containing microencapsulated metal oxide semiconductor particles is coated on the transparent conductive substrate, the pigment-containing microcapsule The encapsulated metal oxide semiconductor particles are arranged at a high density on the transparent conductive substrate, and a dye-sensitized photocell having higher conversion efficiency can be produced. In addition, when the dye-containing microencapsulated metal oxide semiconductor particles are spherical, the coating liquid prepared for coating the dye-containing microencapsulated metal oxide semiconductor particles on the transparent conductive substrate is dispersed. It is excellent in properties and dispersion stability.

  Hereinafter, in the preferred method for producing the dye-containing microencapsulated metal oxide semiconductor particles described above, the dye-containing microencapsulated metal oxide according to the present invention is described with reference to the dispersion state of the metal oxide semiconductor particles in the aqueous dispersion. Embodiments of physical semiconductor particles will be described. However, the dispersion state of the metal oxide semiconductor particles described below includes estimation.

[First Embodiment]
As a first embodiment, an anionic polymerizable surfactant is added to an aqueous dispersion in which metal oxide semiconductor particles are dispersed to form an admicelle, followed by polymerization with a polymerization initiator. 2 shows encapsulated metal oxide semiconductor particles.
FIG. 3 shows that the metal oxide semiconductor particle 31 has a water-based solvent (hereinafter referred to as an aqueous solvent) by an anionic polymerizable surfactant 20 having an anionic group 22, a hydrophobic group 21, and a polymerizable group 23. It is a figure (however, a pigment | dye is not shown) which shows the state disperse | distributed to (it is also called). Since the surface 34 of the metal oxide semiconductor particle 31 is a hydrophobic region, the hydrophobic group 21 is converted into the metal oxide semiconductor particle 31 by the interaction between the surface 34 and the hydrophobic group 21 of the anionic polymerizable surfactant 20. Adsorbed toward The anionic group 22 of the anionic polymerizable surfactant 20 is oriented in the direction in which the aqueous solvent exists, that is, in the direction away from the metal oxide semiconductor particles 31.

For example, a polymerization initiator is added to this aqueous dispersion to polymerize the polymerizable group 23 of the anionic polymerizable surfactant 20, thereby producing a metal as shown in FIG. 4 (however, the dye is not shown). A dye-containing microencapsulated metal oxide semiconductor particle 3 in which the oxide semiconductor particle 31 is coated with the organic polymer compound layer 32 is produced. Here, since the surface of the organic polymer compound layer 32 has the anion group 22, the dye-containing microencapsulated metal oxide semiconductor particles 3 can be dispersed in an aqueous solvent.
In addition to the anionic polymerizable surfactant 20, a comonomer copolymerizable with the anionic polymerizable surfactant 20 may be present in the aqueous dispersion as necessary. In this case, the organic polymer compound layer 32 can be an organic polymer compound layer obtained by copolymerizing the anionic polymerizable surfactant 20 and the comonomer.

[Second Embodiment]
As a second embodiment, a metal oxide semiconductor particle having an anionic group on its surface is a repeating structural unit derived from a cationic polymerizable surfactant, and a repeating structural unit derived from an anionic polymerizable surfactant The pigment | dye containing microencapsulated metal oxide semiconductor particle | grains coat | covered with the organic polymer compound which has these are shown.
FIG. 5 shows a metal oxide semiconductor particle 31 having an anionic group 22 dispersed in a solvent containing water as a main component (hereinafter also referred to as an aqueous solvent), a cationic group 41 and a hydrophobic group 42. An admicelle is formed by the cationic polymerizable surfactant 40 having the polymerizable group 43 and the anionic polymerizable surfactant 20 having the anionic group 22, the hydrophobic group 21, and the polymerizable group 23. It is a figure which shows a state (however, a pigment | dye is not shown). The cationic group 41 of the cationic polymerizable surfactant 40 is adsorbed on the anionic group 22 of the metal oxide semiconductor particle 31 with a strong ionic bond, and anionic polymerization is performed on the hydrophobic group 42 and the polymerizable group 43. The hydrophobic group 21 and the polymerizable group 23 of the surfactant 20 are adsorbed by hydrophobic interaction, and the anionic group 22 is directed in the direction in which the aqueous solvent exists, that is, in the direction away from the metal oxide semiconductor particles.

For example, by adding a polymerization initiator to this aqueous dispersion to polymerize the polymerizable group 43 of the cationic polymerizable surfactant 40 and the polymerizable group 23 of the anionic polymerizable surfactant 20, FIG. As shown (however, the dye is not shown), the dye-containing microencapsulated metal oxide semiconductor particles 3 in which the metal oxide semiconductor particles 31 are coated with the organic polymer compound layer 32 are produced.
In the case where a hydrophilic monomer having an anionic group as a hydrophilic group is used instead of the anionic polymerizable surfactant 20, a dye-containing microencapsulated metal oxide semiconductor particle can be produced in the same manner. In the polymerization, the cationic polymerizable surfactant and an anionic polymerizable surfactant and / or a hydrophilic monomer having an anionic group can be copolymerized in an aqueous dispersion as required. A comonomer may be present, in which case the polymer layer is copolymerized from a cationic polymerizable surfactant, an anionic polymerizable surfactant and / or a hydrophilic monomer having an anionic group, and a comonomer. Copolymer layer.

  Further, the dye-containing microencapsulated metal oxide semiconductor particles used in the dye-sensitized photovoltaic cell of the present invention are formed as admicelles using a polymerizable surfactant as a core substance and the metal oxide semiconductor particles as a core substance, In the case of preparing by carrying out a polymerization reaction after including a dye, it is preferable to use a dye having a polymerizable reactive group as the dye to be included in the admicelle. This example will be described with reference to FIGS.

  FIG. 9 shows polymerization of a cationic group 41 and a hydrophobic group 42 on a metal oxide semiconductor particle 31 having an anionic group 22 dispersed on a surface of a solvent containing water as a main component (hereinafter also referred to as an aqueous solvent). An amide cell is formed by the cationic polymerizable surfactant 40 having the ionic group 43 and the anionic polymerizable surfactant 20 having the anionic group 22, the hydrophobic group 21, and the polymerizable group 23. It is a figure which shows the state in which the pigment | dye 33 which has the polymeric group 36 exists. The cationic group 41 of the cationic polymerizable surfactant 40 is adsorbed on the anionic group 22 of the metal oxide semiconductor particle 31 with a strong ionic bond, and anionic polymerizable with respect to the hydrophobic group 42 and the polymerizable group 43. The hydrophobic group 21 and the polymerizable group 23 of the surfactant 20 are adsorbed by hydrophobic interaction, and the anionic group 22 is directed in the direction in which the aqueous solvent exists, that is, in the direction away from the metal oxide semiconductor particles. A dye 33 having a polymerizable group 36 is disposed in the amide cell, that is, between the cationic polymerizable surfactant 40 and the anionic polymerizable surfactant 20.

  For example, a polymerization initiator is added to such an aqueous dispersion to form a polymerizable group 43 of the cationic polymerizable surfactant 40, a polymerizable group 23 of the anionic polymerizable surfactant 20, and a polymerizable group of the dye 50. By polymerizing 51, as shown in FIG. 10, the dye-containing microencapsulated metal oxide semiconductor particles 3 in which the metal oxide semiconductor particles 31 are coated with the polymer layer 32 containing the dye 50 are produced.

In the first and second embodiments, the form formed by emulsion polymerization was shown. However, the dye-containing microencapsulated metal oxide semiconductor particles used in the present invention were formed by miniemulsion polymerization. May be. The dye-containing microencapsulated metal oxide semiconductor particles formed by this miniemulsion polymerization can also produce a dye-sensitized photocell satisfying the problems of the present invention.
Here, the “miniemulsion polymerization method” means that an ionic polymerizable surfactant having an ionic group, a hydrophobic group and a polymerizable group and a copolymerizable monomer are co-surfactant in the presence of pigment particles. A polymerization reaction in the presence of an agent. In miniemulsion polymerization, the co-surfactant can coexist to form admicelles with pigment particles in the core more stably, so the particle size of the dye-containing microencapsulated metal oxide semiconductor particles is controlled. Dye-containing microencapsulated metal oxide semiconductor particles that are easy and have a uniform particle size (narrow particle size distribution) can be obtained. The timing for adding the co-surfactant is preferably the same as the addition of the ionic polymerizable surfactant having an ionic group, a hydrophobic group, and a polymerizable group, and a copolymerizable monomer.

As the co-surfactant, known ones generally used in the “miniemulsion polymerization method” can be used. Examples of suitable co-surfactants include alkanes having 8 to 30 carbon atoms such as dodecane, hexadecane and octadecane, alkyl alcohols having 8 to 30 carbon atoms such as lauryl alcohol, cetyl alcohol and stearyl alcohol, lauryl (meta C8-C30 alkyl (meth) acrylates such as acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, dodecyl methacrylate, etc., C8-C30 alkylthiols such as lauryl mercaptan, cetyl mercaptan, stearyl mercaptan And other polymers such as polystyrene and polymethyl methacrylate, polyadducts, carboxylic acids, ketones, amines and the like.
The “miniemulsion polymerization method” is described in, for example, PLTang, ED Sudol, CASilebi, MSEl-Aasser; J. Appl. Polym. Sci., Vol. 43, page 1059 (1991).

Next, components constituting the coating polymer of the dye-containing microencapsulated metal oxide semiconductor particles (cationic polymerizable surfactant, hydrophobic monomer, anionic polymerizable surfactant, hydrophilic monomer, and other comonomers, etc. ).
[Cationically polymerizable surfactant]
The cationic polymerizable surfactant used in the present invention is a compound having a cationic group that is an ionic group, a hydrophobic group, and a polymerizable group. As the cationic group of the cationic polymerizable surfactant, a cationic group selected from the group consisting of a primary ammonium cation, a secondary ammonio cation, a tertiary ammonio cation, and a quaternary ammonium cation is preferable. The monoammonium cation (RNH ₃ ⁺ ) and the like as the primary ammonium cation, the dialkylammonium cation (R ₂ NH ₂ ⁺ ) and the like as the secondary ammonium cation, and the trialkylammonium cation (R ₃ ) as the tertiary ammonium cation. NH ⁺ ) and the like, and examples of the quaternary ammonium cation include (R ₄ N ⁺ ) and the like. Here, R is a hydrophobic group and a polymerizable group, and examples thereof include those shown below.
Examples of the counter anion of the above-mentioned cationic group include Cl ⁻ , Br ⁻ and I ⁻ .
The hydrophobic group is preferably selected from the group consisting of an alkyl group, an aryl group, and a group in which these are combined.
The polymerizable group is preferably an unsaturated hydrocarbon group, and more specifically selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group, and a vinylene group. preferable. Among these, an acryloyl group and a methacryloyl group can be exemplified as preferable examples.

  Specific examples of the cationic polymerizable surfactant include a cationic allylic acid derivative as described in JP-B-4-65824, a methacrylic acid derivative, an acrylic acid derivative, and the like. be able to.

The cationic polymerizable surfactants used in the present invention, for example, the general formula _{R [4- (l + m +} n)] R 1 l R 2 m R 3 n N + · X - a compound represented by (R is a polymerizable group, R ¹ , R ² and R ³ are each an alkyl group or an aryl group, X is Cl, Br or I, and l, m and n are each 1; Or 0.) Here, as the polymerizable group, a hydrocarbon group having an unsaturated hydrocarbon group capable of radical polymerization can be preferably exemplified, and more specifically, an allyl group, an acroyl group, a methacryloyl group, a vinyl group, a propylene group, and a propylene group. Nyl group, vinylidene group, vinylene group and the like can be mentioned.

  Specific examples of the cationic polymerizable surfactant include dimethylaminoethyl methyl chloride methacrylate, dimethylaminoethyl benzyl methacrylate, methacryloyloxyethyltrimethylammonium chloride, diallyldimethylammonium chloride, 2-hydroxy-3 -A methacryloxypropyl trimethyl ammonium chloride salt etc. can be mentioned.

A commercial item can also be used as said cationic polymerizable surfactant. Examples include Acryester DMC (Mitsubishi Rayon Co., Ltd.), Acryester DML60 (Mitsubishi Rayon Co., Ltd.), C-1615 (Daiichi Kogyo Seiyaku Co., Ltd.), and the like.
The cationic polymerizable surfactants exemplified above can be used alone or as a mixture of two or more.

[Anionic polymerizable surfactant]
The anionic polymerizable surfactant used in the present invention is a compound having an anionic group that is an ionic group, a hydrophobic group, and a polymerizable group.
Specific examples of the anionic polymerizable surfactant used in the present invention are described in JP-B-49-46291, JP-B-1-24142, or JP-A-62-104802. Anionic allyl derivatives, anionic propenyl derivatives as described in JP-A-62-221431, JP-A-62-34947 or JP-A-55-11525 Examples of such anionic acrylic acid derivatives include anionic itaconic acid derivatives as described in JP-B-46-34898 or JP-A-51-30284.

  Examples of the anionic polymerizable surfactant used in the present invention include a general formula (31):

[Wherein, R ²¹ and R ³¹ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and Z ¹ represents a carbon-carbon single bond or a formula —CH ₂ —O—CH ₂ −
M is an integer of 2 to 20,
X is a group represented by the formula —SO ₃ M ¹ , and M ¹ is an alkali metal, an ammonium salt, or an alkanolamine]
Or a compound represented by formula (32):

[Wherein, R ²² and R ³² each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and D represents a carbon-carbon single bond or a formula

—CH ₂ —O—CH ₂ —

N is an integer of 2 to 20,
Y is a group represented by the formula —SO ₃ M ² , and M ² is an alkali metal, an ammonium salt, or an alkanolamine]
The compound represented by these is preferable.

The polymerizable surfactant represented by the formula (31) is described in JP-A-5-320276 or JP-A-10-316909. By appropriately adjusting the type of R ²¹ and the value of x in the formula (31), it is possible to correspond to the degree of hydrophilicity or hydrophobicity of the surface of the metal oxide semiconductor particles. As a preferable polymerizable surfactant represented by the formula (31), a compound represented by the following formula (310) can be exemplified. Specifically, in the following formulas (31a) to (31d) Mention may be made of the compounds represented.

[Wherein R ³¹ , m and M ¹ are the same as the compound represented by formula (31)]

A commercial item can also be used as said anionic polymerizable surfactant. For example, Aqualon HS series (Aqualon HS-05, HS-10, HS-20, HS-1025) (above, trade name) from Daiichi Kogyo Seiyaku Co., Ltd. or Adekaria soap SE- from Asahi Denka Kogyo Co. 10N, SE-20N (above, trade name) and the like.
Adeka Soap SE-10N manufactured by Asahi Denka Kogyo Co., Ltd. is a compound represented by formula (310) in which M ¹ is NH ₄ , R ³¹ is C ₉ H ₁₉ , and m = 10. Adeka Soap SE-20N manufactured by Asahi Denka Kogyo Co., Ltd. is a compound represented by the formula (310) in which M ¹ is NH ₄ , R ³¹ is C ₉ H ₁₉ , and m = 20.

  Examples of the anionic polymerizable surfactant used in the present invention include a general formula (33):

[Wherein p is 9 or 11, q is an integer of 2 to 20, A is a group represented by —SO ₃ M ³ , and M ³ is an alkali metal, an ammonium salt or an alkanolamine]
The compound represented by these is preferable. Preferred examples of the anionic polymerizable surfactant represented by the formula (33) include the following compounds.

[Wherein r is 9 or 11, s is 5 or 10]

  A commercial item can also be used as said anionic polymerizable surfactant. For example, Aqualon KH series (Aqualon KH-5, Aqualon KH-10 (above, trade name)) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. can be exemplified. Aqualon KH-5 is a mixture of a compound represented by the above formula wherein r is 9 and s is 5 and a compound where r is 11 and s is 5. Aqualon KH-10 is a mixture of a compound represented by the above formula wherein r is 9 and s is 10, and a compound where r is 11 and s is 10.

  Moreover, as an anionic polymerizable surfactant, the compound represented by the following formula (A) is also preferable.

[In the above formula, R ⁴ represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, l represents a number of 2 to 20, and M ⁴ represents an alkali metal, an ammonium salt, or an alkanolamine. ]

  The anionic polymerizable surfactants exemplified above can be used alone or as a mixture of two or more.

The addition amount of the anionic polymerizable surfactant is preferably in the range of about 5 to 70 parts by weight, more preferably in the range of 10 to 50 parts by weight with respect to 100 parts by weight of the metal oxide semiconductor particles.
Moreover, when using together an anionic polymerizable surfactant and a cationic polymerizable surfactant, the addition amount of an anionic polymerizable surfactant is 1 time-10 times with respect to a cationic polymerizable surfactant. A range of about 1 mol is more preferable, and a range of about 1 to 5 mol is more preferable.

The anionic group of the anionic polymerizable surfactant is considered to be present on the capsule surface after being microencapsulated and oriented on the aqueous phase side.
The hydrophilic monomer having an anionic group that can be used in the present invention has at least an anionic group and a polymerizable group as a hydrophilic group in the structure, and the hydrophilic group is a sulfonic acid group or a sulfinic acid group. And those selected from the group of carboxyl groups, carbonyl groups and salts thereof.
The polymerizable group is an unsaturated hydrocarbon group capable of radical polymerization, and is preferably selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group, and a vinylene group. .

  Preferable specific examples of the hydrophilic monomer having an anionic group include, for example, methacrylic acid, acrylic acid, phosphoric acid group-containing (meth) acrylate, sodium vinyl sulfonate, 2-sulfoethyl methacrylate, 2-acrylamido-2-methyl. And propanesulfonic acid.

  The addition amount of the hydrophilic group monomer having an anionic group is preferably in the range of about 1 to 10 times mol, more preferably 1.0 to 5 times the molar amount of the cationic polymerizable surfactant. It is in the range of about a mole. By setting the addition amount to 1 mol or more, the dispersibility and dispersion stability of the encapsulated particles are excellent, and the discharge stability is also excellent. By setting the addition amount to 10 times mol or less, it is possible to suppress the generation of hydrophilic monomers that do not contribute to encapsulation, and to prevent the generation of polymer particles in addition to the capsule particles.

  In the case where an anionic polymerizable surfactant and a hydrophilic group monomer having an anionic group are used in combination, the total amount of addition is about 1 to 10 times mol with respect to the cationic polymerizable surfactant. Is more preferable, and more preferably in the range of about 1.0 to 5 times mole. As described above, when the addition amount is 1 mol or more, the dispersibility and dispersion stability of the encapsulated particles are excellent. By setting the addition amount to 10 times or less, the generation of hydrophilic monomers that do not contribute to encapsulation can be suppressed, and the generation of polymer particles other than the encapsulated particles can be prevented.

Furthermore, other comonomers may be added.
Examples of other comonomers include hydrophilic monomers (hydrophilic monomers other than the hydrophilic monomers having an anionic group) and / or hydrophobic monomers.

  Examples of the hydrophilic monomer other than the hydrophilic monomer having an anionic group include those having a hydroxyl group, an ethylene oxide group, an amide group, or an amino group as the hydrophilic group.

  Examples of hydrophilic monomers other than hydrophilic monomers having an anionic group include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, etc. having an OH group, ethyl diethylene glycol acrylate having an ethylene oxide group, polyethylene glycol Monomethacrylate, methoxypolyethylene glycol methacrylate, etc., acrylamide having an amide group, N, N-dimethylacrylamide, etc., N-methylaminoethyl methacrylate containing amino group, N-methylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate Acrylic acid or meta, such as diethylaminoethyl methacrylate, diethylaminoethyl methacrylate Alkylamino esters of silyl acid; unsaturated amides having alkylamino groups such as N- (2-dimethylaminoethyl) acrylamide, N- (2-dimethylaminoethyl) methacrylamide, N, N-dimethylaminopropylacrylamide, etc. And vinyl ethers having an alkylamino group such as dimethylaminoethyl vinyl ether; vinyl imidazole, N-vinyl-2-pyrrolidone, and the like.

  The dye-containing microencapsulated metal oxide semiconductor particle according to the present invention has a cationic polymerizable surface active activity in which the metal oxide semiconductor particle having an anionic group on the surface has a cationic group, a hydrophobic group, and a polymerizable group. A repeating structural unit derived from an agent, an anionic polymerizable surfactant having an anionic group, a hydrophobic group and a polymerizable group and / or a repeating structural unit derived from a hydrophilic monomer having an anionic group In addition, it may further have a repeating structural unit derived from a hydrophobic monomer.

The hydrophobic monomer has at least a hydrophobic group and a polymerizable group in its structure, and the hydrophobic group is selected from the group consisting of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Can be illustrated. Examples of the aliphatic hydrocarbon group include a methyl group, an ethyl group, and a propyl group. Examples of the alicyclic hydrocarbon group include a cyclohexyl group, a dicyclopentenyl group, a dicyclopentanyl group, and an isobornyl group, and an aromatic hydrocarbon group. Examples thereof include a benzyl group, a phenyl group, and a naphthyl group.
The polymerizable group is an unsaturated hydrocarbon group capable of radical polymerization, and is preferably selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group, and a vinylene group. .

  Specific examples of the hydrophobic monomer include styrene and styrene derivatives such as methylstyrene, dimethylstyrene, chlorostyrene, dichlorostyrene, bromostyrene, and p-chloromethylstyrene; methyl acrylate, ethyl acrylate, and n-butyl acrylate. , Butoxyethyl acrylate, benzyl acrylate, phenyl acrylate, phenoxyethyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, etc. Monofunctional acrylic esters of methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, butoxymethyl Monofunctional, such as tacrylate, benzyl methacrylate, phenyl methacrylate, phenoxyethyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyloxyethyl methacrylate, tetrahydrofurfuryl methacrylate, isobornyl methacrylate Methacrylic acid esters; allyl compounds such as allylbenzene, allyl-3-cyclohexanepropionate, 1-allyl-3,4-dimethoxybenzene, allylphenoxyacetate, allylphenylacetate, allylcyclohexane, allyl polycarboxylic acid allyl; Acid, maleic acid, itaconic acid ester cheek; N-substituted maleimide, cyclic olefin and other monomers having radical polymerizable groups It is.

  As the hydrophobic monomer, those satisfying the above-mentioned required characteristics are appropriately selected, and the addition amount thereof is arbitrarily determined.

  In the present invention, a crosslinkable monomer can be used. Examples of the crosslinkable monomer that can be used in the present invention include compounds having two or more unsaturated hydrocarbon groups selected from a vinyl group, an allyl group, an acryloyl group, a methacryloyl group, a propenyl group, a vinylidene group, and a vinylene group. For example, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, allyl acrylate, bis (acryloxyethyl) hydroxyethyl isocyanurate, bis (acryloxy) Neopentyl glycol) adipate, 1,3-butylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, Pyrene glycol diacrylate, polypropylene glycol diacrylate, 2-hydroxy-1,3-diaacryloxypropane, 2,2-bis [4- (acryloxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy) ) Phenyl] propane, 2,2-bis [4- (acryloxyethoxy diethoxy) phenyl] propane, 2,2-bis [4- (acryloxyethoxy polyethoxy) phenyl] propane, hydroxypentyl glycol neopentyl glycol Diacrylate, 1,4-butanediol diacrylate, dicyclopentanyl diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, ditrimethylolpropane tetraacrylate, penta Lithritol triacrylate, tetrabromobisphenol A diacrylate, triglycerol diacrylate, trimethylolpropane triacrylate, tris (acryloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol Dimethacrylate, polyethylene glycol dimethacrylate, propylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate 2-hydroxy-1,3-dimetac Liloxypropane, 2,2-bis [4- (methacryloxy) phenyl] propane, 2,2-bis [4- (methacryloxyethoxy) phenyl] propane, 2,2-bis [4- (methacryloxyethoxydiethoxy) ) Phenyl] propane, 2,2-bis [4- (methacryloxyethoxypolyethoxy) phenyl] propane, tetrabromobisphenol A dimethacrylate, dicyclopentanyl dimethacrylate, dipentaerythritol hexamethacrylate, glycerol dimethacrylate, hydroxybiba Neopentyl glycol dimethacrylate phosphate, dipentaerythritol monohydroxypentamethacrylate, ditrimethylolpropane tetramethacrylate, pentaerythritol trimethacrylate, pentaerythritol Tetramethacrylate, triglycerol dimethacrylate, trimethylolpropane trimethacrylate, tris (methacryloxyethyl) isocyanurate, allyl methacrylate, divinylbenzene, diallyl phthalate, diallyl terephthalate, diallyl isophthalate, diethylene glycol bis allyl carbonate.

  The addition amount of the crosslinkable monomer is preferably in the range of 0.01-fold to 0.5-fold mole with respect to the hydrophobic monomer.

  As described above, the polymer constituting the capsule wall material of the dye-containing microencapsulated metal oxide semiconductor particles of the present invention is obtained by polymerizing an ionic polymerizable surfactant and a monomer containing a hydrophobic macromonomer. It is done. This polymerization reaction can be performed using a known polymerization initiator, and it is particularly preferable to use a radical polymerization initiator. As such a polymerization initiator, a water-soluble polymerization initiator is preferable, and potassium persulfate, ammonium persulfate, sodium persulfate, 2,2-azobis- (2-methylpropionamidine) dihydrochloride, or 4,4 -Azobis- (4-cyanovaleric acid) and the like.

A method for producing the dye-containing microencapsulated metal oxide semiconductor particles of the present invention will be described below.
The capsule wall material (polymer layer) of the dye-containing microencapsulated metal oxide semiconductor particles is synthesized by a polymerization reaction, and this polymerization reaction is performed using an ultrasonic generator, a stirrer, a reflux condenser, a dropping funnel, and a temperature controller. It is preferable to carry out using the reaction vessel provided.
As the first aspect of the method for producing the dye-containing microencapsulated metal oxide semiconductor particles of the present invention, first, (1) the metal oxide semiconductor particles have an ionic group, a hydrophobic group, and a polymerizable group. A polymerizable surfactant and water are added and mixed, and the polymerizable surfactant is adsorbed on the metal oxide semiconductor particles by a general disperser such as a ball mill, a roll mill, an Eiger mill, or a jet mill. Step of dispersing semiconductor particles in water, then (2) organometallic complex dye, pyridine dye, phthalocyanine dye, porphyrin dye, cyanine dye, merocyanine dye, coumarin dye, polymethine dye, mercurochrome dye A step of adding and mixing a hydrophobic monomer in which a pigment such as eosin pigment is dissolved, and (3) an ionic group, a hydrophobic group, and Admixing added a polymerizable surfactant having a polymerizable group, and, there is a manufacturing method comprising a step of performing emulsion polymerization by the addition of (4) a polymerization initiator. The dye used in (2) may be a dye having a polymerizable group.

  As a second aspect of the method for producing the dye-containing microencapsulated metal oxide semiconductor particles of the present invention, the aqueous dispersion containing the metal oxide semiconductor particles having an ionic group on the surface includes (1) the metal oxide A polymerizable surfactant having an ionic group, a hydrophobic group, and a polymerizable group having a charge opposite to the charge of the ionic group on the surface of the semiconductor particle is added and mixed, and the polymerizable property is added to the metal oxide semiconductor particle. (2) Furthermore, an organometallic complex dye, a pyridine dye, a phthalocyanine dye, a porphyrin dye, a cyanine dye, a merocyanine dye, a coumarin dye, a polymethine dye, a mercurochrome dye, A step of adding and mixing a hydrophobic monomer in which a dye such as an eosin dye is dissolved, and (3) an ionic group on the surface of the metal oxide semiconductor particle A step of adding and mixing a polymerizable surfactant having an ionic group, a hydrophobic group, and a polymerizable group having the same or opposite charge as the charge; and (4) emulsion polymerization by adding a polymerization initiator. There is a manufacturing method comprising steps. The dye used in (2) may be a dye having a polymerizable group.

  As a third aspect of the method for producing a dye-containing microencapsulated metal oxide semiconductor particle of the present invention, an aqueous dispersion containing a metal oxide colloid having an ionic group on its surface is used. (1) The metal oxide colloid A polymerizable surfactant having an ionic group, a hydrophobic group, and a polymerizable group having a charge opposite to the charge of the ionic group on the particle surface is added and mixed, and the polymerizable interface is added to the metal oxide colloidal particle. (2) Further, an organometallic complex dye, a pyridine dye, a phthalocyanine dye, a porphyrin dye, a cyanine dye, a merocyanine dye, a coumarin dye, a polymethine dye, a mercurochrome dye, eosin A step of adding and mixing a hydrophobic monomer in which a dye such as a dye is dissolved, and (3) an ionic group on the surface of the metal oxide colloid A step of adding and mixing a polymerizable surfactant having an ionic group, a hydrophobic group, and a polymerizable group having the same or opposite charge as the charge; and (4) emulsion polymerization by adding a polymerization initiator. There is a manufacturing method comprising steps. The dye used in (2) may be a dye having a polymerizable group.

  As a specific aspect of the second aspect of the method for producing a microencapsulated pigment of the present invention, a case where metal oxide semiconductor particles having an anionic group on the surface are used will be described. First, (1) an aqueous dispersion containing metal oxide semiconductor particles having an anionic group on the surface is prepared. When the metal oxide semiconductor particles having an anionic group on the surface are not well dispersed in an aqueous medium, a general dispersing machine such as a ball mill, a roll mill, an Eiger mill, or a jet mill is used as a treatment before polymerization. It is preferable to disperse the metal oxide semiconductor particles in an aqueous medium using Next, (2) a polymerizable surfactant having a cationic group, a hydrophobic group, and a polymerizable group (hereinafter also simply referred to as “cationic polymerizable surfactant”) is added to the aqueous dispersion. And mix. At this time, in order to mix the metal oxide semiconductor particles and the cationic polymerizable surfactant well, it is preferable to irradiate the mixture with ultrasonic waves. Here, the cationic group of the cationic polymerizable surfactant is adsorbed and ionically bonded to the anionic group of the metal oxide semiconductor particle having the anionic group on the surface, and is immobilized. Next, (3) In this aqueous dispersion, an organometallic complex dye, pyridine dye, phthalocyanine dye, porphyrin dye, cyanine dye, merocyanine dye, coumarin dye, polymethine dye, mercurochrome dye, eosin A hydrophobic monomer in which a dye such as a system dye is dissolved is added and mixed. At this time, in addition to the hydrophobic monomer, the cationic polymerizable surfactant and a monomer copolymerizable with the hydrophobic monomer (for example, a crosslinkable monomer) are added as long as the effects of the invention are not impaired. can do. Also in this step, it is preferable to irradiate the aqueous dispersion with ultrasonic waves. Thereafter, (4) a polymerizable surfactant having an anionic group, a hydrophobic group and a polymerizable group (hereinafter also simply referred to as “anionic polymerizable surfactant”) is added to the aqueous dispersion. And mix. At this time, in addition to the anionic polymerizable surfactant, a hydrophilic monomer can be added as long as the effects of the invention are not impaired. Also in this step, it is preferable to irradiate the aqueous dispersion with ultrasonic waves. Next, (5) a polymerization initiator is added to the aqueous dispersion obtained above to carry out an emulsion polymerization reaction. The polymerization initiator may be added to the aqueous dispersion heated to a temperature at which the polymerization initiator is activated, all at once or dividedly, or continuously. Further, after adding the polymerization initiator, the aqueous dispersion may be heated to a temperature at which the polymerization initiator is activated. In the present invention, it is preferable to use a water-soluble polymerization initiator as a polymerization initiator and add dropwise an aqueous polymerization initiator solution obtained by dissolving it in deionized water into the aqueous dispersion in the reaction vessel. The added polymerization initiator is cleaved to generate initiator radicals, which attack the polymerizable surfactant and the polymerizable group of the hydrophobic monomer to cause a polymerization reaction. The polymerization temperature and polymerization reaction time vary depending on the type of polymerization initiator used and the type of polymerizable surfactant and hydrophobic monomer, but those skilled in the art can easily set preferable polymerization conditions as appropriate. In general, the polymerization temperature is preferably in the range of 60 to 90 ° C., and the polymerization reaction time is preferably 3 to 10 hours. The dye used in (3) may be a dye having a polymerizable group. According to the emulsion polymerization method described above, first, a cationic polymerizable surfactant is adsorbed on the anionic group on the surface of the metal oxide semiconductor particle, and then an organometallic complex dye, a pyridine dye, a phthalocyanine dye, and a porphyrin dye. Hydrophobic monomers in which cyanine dyes, merocyanine dyes, coumarin dyes, polymethine dyes, mercurochrome dyes, eosin dyes and the like are dissolved are added, and an anionic polymerizable surfactant is added, and ultrasonic waves are added. By treating with an organic metal complex dye, pyridine dye, phthalocyanine dye, porphyrin dye, cyanine dye, merocyanine dye, coumarin dye, polymethine dye, mercurochrome dye, eosin dye, etc. Hydrophobic monomer in which the dye is dissolved is localized and further outside On polymerizable surfactant is estimated anionic groups and oriented toward the aqueous phase side admicell (admicell) is formed. Inclusion of a dye coated with a polymer having a repeating structural unit derived from a cationic polymerizable surfactant, a hydrophobic monomer, and a repeating structural unit derived from an anionic polymerizable surfactant by the above-described process Microencapsulated metal oxide semiconductor particles can be preferably produced.

For the metal oxide semiconductor particles having a cationic group on the surface, the dye of the embodiment of the present invention is obtained by the same process as described above except that the cationic polymerizable surfactant is changed to an anionic polymerizable surfactant. Inclusion microencapsulated metal oxide semiconductor particles can be produced.
Then, the monomer is polymerized by emulsion polymerization while the monomer molecules are highly controlled around the metal oxide semiconductor particles to form a polymer, and the dye-containing microencapsulated metal oxide semiconductor particles of the present invention are obtained. it is conceivable that.

  The addition amount of the cationic polymerizable surfactant is the total number of moles of anionic groups relative to the amount of metal oxide semiconductor particles having an anionic group on the surface (= weight of the metal oxide semiconductor particles used (g) × The range of 0.5 to 2 times mol is preferable, and the range of 0.8 to 1.2 times mol is more preferable with respect to the anionic group (mol / g) of the metal oxide semiconductor particle surface. By setting the addition amount to 0.5 times mol or more, the metal oxide semiconductor particles having an anionic group as a hydrophilic group are strongly ionically bound and can be easily encapsulated. By setting the addition amount to 2 times or less, it is possible to reduce generation of a cationic polymerizable surfactant that is not adsorbed on the metal oxide semiconductor particles, and polymer particles that do not have the metal oxide semiconductor particles as a core substance. Generation | occurrence | production of (the particle | grains which consist only of a polymer) can be prevented.

The dye-containing microencapsulated metal oxide semiconductor particles according to the embodiment of the present invention obtained as described above are completely covered with a polymer layer of metal oxide semiconductor particles having a small average particle diameter (no defect portion). ).
The particle diameter of the dye-containing microencapsulated metal oxide semiconductor particles according to this embodiment is preferably 200 nm or less, more preferably 100 nm or less, and particularly preferably 20 to 100 nm.

  The dye-containing microencapsulated metal oxide semiconductor particles as described above can also be provided on a substrate by an inkjet method or the like when a dye-sensitized photocell described later in detail is manufactured.

The dye-containing microencapsulated metal oxide semiconductor particles are formed, for example, on a transparent conductive substrate, and the vacancies of the metal oxide semiconductor layer are filled with a charge transport layer, and the charge transport layer is connected to the counter electrode. As a structure to be brought into contact with a conductive film to be formed and / or a conductive film to be a catalyst, it is used for a dye-sensitized photovoltaic cell.
A more specific structure of the dye-sensitized photocell using the dye-containing microencapsulated metal oxide semiconductor particles includes at least a transparent conductive layer, a dye-containing microencapsulated metal oxide semiconductor particle layer, and charge transport on a substrate. A layer, a conductive catalyst layer, and / or a conductive layer are sequentially formed.
More specifically, as shown in FIG. 1, substrate 1, transparent conductive layer 2, dye-containing microencapsulated metal oxide semiconductor particles 3, charge transport layer 4, conductive catalyst layer 5, transparent conductive layer 6, base What consists of the material 7 is mentioned as an example of embodiment of this invention.

  As the base materials 1 and 7 used in the above embodiment, glass or plastic film such as polymethyl methacrylate, polycarbonate, polystyrene, polyethylene sulfide, polyethersulfone, polyolefin, polyethylene terephthalate, polyethylene naphthalate, triacetyl cellulose and the like are used. Although it can be used, there is no limitation as long as it is an insulating and transparent substrate. Furthermore, a substrate with light resistance and heat resistance is preferable from the viewpoint of the environment in which the solar cell is used and the lifetime. In order to effectively take in incident light, an antireflection layer may be provided on the surface of the substrate used for the photoelectrode where the transparent conductive layer is not laminated.

  As the transparent conductive layers 2 and 6 in the above embodiment, tin oxide, zinc oxide doped with fluorine, indium, or the like, and other transparent transparent conductors with little absorption in the visible light region are preferable.

  The transparent conductive layers 2 and 6 can be formed by any vacuum deposition process such as vacuum deposition, reactive deposition, ion beam assisted deposition, sputtering, ion plating, plasma CVD, etc. A film forming method may be used.

The method for forming the metal oxide semiconductor layer is not particularly limited, but a dispersion of the dye-containing microencapsulated metal oxide semiconductor particles 3 is applied on the transparent conductive layer 2;
The method of drying etc. are mentioned.

  Alternatively, a metal oxide semiconductor layer containing carbon can be used. More preferably, it contains about 1 to 30 at% of carbon atoms.

  As the electrolyte contained in the charge transport layer 4 in the present invention, materials generally used for the charge transport layer of a dye-sensitized battery can be arbitrarily used. For example, iodides including iodine, bromides, quinone complexes, TCNQ Complexes, dicyanoquinone diimine complexes, and others are preferred.

  In the charge transport layer 4 of the present invention, a solid charge transport layer containing a solid electrolyte or a p-type semiconductor can be used. Such a charge transport layer is preferable because there is no possibility of liquid leakage that may occur when a liquid charge transport layer is used.

  Specific examples of materials that can be used for the solid charge transport layer include, as donor skeletons, aromatic amine compounds such as triphenylamine, diphenylamine, and phenylenediamine, condensed polycyclic hydrocarbons such as naphthalene, anthracene, and bilen, and azobenzene. Azo compounds, compounds having a structure in which aromatic rings such as stilbene are linked by ethylene bonds or acetylene bonds, heteroaromatic compounds substituted with amino groups, porphyrins, phthalocyanines, etc., and acceptor skeletons are quinones , Tetracyanoquinodimethanes, dicyanoquinone diimines, tetracyanoethylene, viologens, dithiol metal complexes and the like. Other materials that can be used for the solid charge transport layer include CuI, AgI, TiI, and other metal iodides, CuBr, CuSCN, and the like. Further, an iodide, a quinone complex, or the like may be included in a polymer gel such as polyalkylene ether. These materials can be used in any combination as required.

  As the method for forming the charge transport layer 4 in the present invention, coating such as dipping, spin coater, bar coater, blade coater, knife coater, reverse roll coater, gravure roll coater, squeeze coater, curtain coater, spray coater, die coater, etc. A method capable of continuous coating is more preferable. In the case of using a solid electrolyte or p-type semiconductor, it is formed by forming a solution using an arbitrary solvent, applying the solution using the above method, and heating the substrate 1 to an arbitrary temperature to evaporate the solvent. To do.

  As the conductive catalyst layer 5 used in the present invention, any conductive material can be used, and examples thereof include metals such as platinum, gold, silver, and copper, or carbon. When these are formed, a vacuum film forming method similar to that of the transparent conductive layer 2 or a wet coating method using a paste of fine particles of these materials can be used.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these Examples.
〔Example〕
"Production of dye-containing microencapsulated titanium oxide particles"
1.25 g of Aqualon KH-10 as an anionic polymerizable surfactant was added to and mixed with a titanium oxide sol containing 100 g of titanium oxide particles, and then irradiated with ultrasonic waves for 30 minutes. Next, 1 g of an organometallic complex dye (Ru-acetylacetonato complex) was dissolved in 12 g of isobornyl methacrylate and 6 g of dodecyl methacrylate, added and mixed, and then irradiated with ultrasonic waves for 30 minutes. Next, 3.9 g of the anionic polymerizable surfactant AQUALON KH-10 dissolved in 50 g of ion-exchanged water was added and mixed, and again irradiated with ultrasonic waves for 30 minutes. This was put into a reaction vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a temperature controller, a nitrogen introduction tube and an ultrasonic generator. After the internal temperature of the reaction vessel was raised to 80 ° C., an aqueous potassium persulfate solution in which 0.6 g of potassium persulfate was dissolved as a polymerization initiator was added dropwise to 20 g of ion-exchanged water. Polymerized for hours. After completion of the polymerization, the pH was adjusted to 8 with a 2 mol / l aqueous potassium hydroxide solution, filtered through a membrane filter having a pore size of 1 μm, and coarse particles were removed to obtain a target dye-containing microencapsulated titanium oxide particle dispersion.

"Preparation of dye-sensitized photocell"
A dye-sensitized photovoltaic cell 10 having the layer structure of FIG. 1 was prepared as follows.
First, PET (50 μm thickness) was used as the substrate 1, and indium tin oxide (ITO) was formed thereon as the transparent conductive layer 2 by vacuum sputtering. On this, a dispersion of the dye-containing microencapsulated titanium oxide particles 3 obtained as described above was applied.

Then 1M LiI as the charge-transporting layer 4, 0.05 M I _2, methoxy acetonitrile, 20 wt% polyethylene glycol, to form a gel electrolyte composed of 10 wt% 4-tert-butylpyridine. In the above laminate, indium tin oxide (ITO) formed as a base material 7 on PET (100 μm thickness) by sputtering is formed as a transparent conductive layer 6, and platinum formed by sputtering is further conductive. What was formed as the catalyst layer 5 was laminated so that the film formation surfaces face each other, and the side surfaces were sealed with a silicone-based adhesive resin, thereby producing a dye-sensitized photovoltaic cell 10.

The current-voltage characteristics of the dye-sensitized photocell obtained above were measured. M.M. 1.5 and 100 mW / cm ² of simulated sunlight, the short-circuit current J _SC = 21 mA / cm ² , the open circuit voltage V _OC = 0.68 V, the fill factor FF = 0.70, and the photoelectric conversion efficiency is η = It was 10.0%.

[Comparative Example]
In the “production of dye-containing microencapsulated titanium oxide particles” in the above examples, except that the anionic polymerizable surfactant Aqualon KH-10, isobornyl methacrylate, dodecyl methacrylate is not added, A dye-sensitized photocell was prepared.
Further, the photoelectric conversion efficiency of this prepared dye-sensitized photovoltaic cell for comparison was measured in the same manner as in the above example, and was not satisfied with the example.

It is a conceptual sectional view showing an example of the dye-sensitized photovoltaic cell of the present invention. 1 is a conceptual cross-sectional view showing an example of a dye-containing microencapsulated metal oxide semiconductor particle used in the dye-sensitized photovoltaic cell of the present invention. It is a schematic diagram showing a state in which metal oxide semiconductor particles are dispersed in an aqueous solvent and coexist with an anionic polymerizable surfactant. FIG. 3 is a schematic diagram showing a state in which an anionic polymerizable surfactant is polymerized in the dispersed state shown in FIG. 2. It is a schematic diagram showing a state in which metal oxide semiconductor particles having an anionic group on the surface are dispersed in an aqueous solvent and coexist with a cationic polymerizable surfactant and an anionic polymerizable surfactant. FIG. 6 is a schematic diagram showing a state in which a cationic polymerizable surfactant and an anionic polymerizable surfactant are polymerized in the dispersed state shown in FIG. 5. It is a schematic diagram showing a state in which metal oxide semiconductor particles having an anionic group on the surface are dispersed in an aqueous solvent and coexist with a cationic polymerizable surfactant and an anionic polymerizable surfactant. FIG. 8 is a schematic diagram showing a state in which a cationic polymerizable surfactant and an anionic polymerizable surfactant are polymerized in the dispersed state shown in FIG. 7. The state in which the metal oxide semiconductor particles having an anionic group on the surface are dispersed in an aqueous solvent and coexist with a cationic polymerizable surfactant, an anionic polymerizable surfactant, and a dye having a polymerizable group. It is a schematic diagram shown. FIG. 10 is a schematic diagram illustrating a state in which a cationic polymerizable surfactant, an anionic polymerizable surfactant, and a dye having a polymerizable group are polymerized in the dispersion state illustrated in FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,7 Base material 2 Transparent conductive layer 3 Dye inclusion microencapsulated metal oxide semiconductor particle 4 Charge transport layer 5 Conductive catalyst layer 6 Transparent conductive layer 10 Dye-sensitized photocell 20 Anionic polymerizable surfactant 21, 42 Hydrophobic Group 22 Anionic groups 23, 33, 43 Polymerizable group 31 Metal oxide semiconductor particle 32 Polymer layer 33 Dye 40 Cationic polymerizable surfactant 41 Cationic group

Claims (8)

  Dye-containing microencapsulated metal oxide semiconductor particles that are microencapsulated by coating metal oxide semiconductor particles with an organic polymer compound and that include a dye in the microencapsulated coating film of the organic polymer compound are used. Dye-sensitized photocell.   The dye-containing microencapsulated metal oxide semiconductor particles are obtained by forming an admicelle using a polymerizable surfactant as a core substance and using the metal oxide semiconductor particles as a core material, and including the dye in the admicelle, followed by a polymerization reaction. The dye-sensitized photocell according to claim 1.   The dye-sensitized photovoltaic cell according to claim 2, which is polymerized with another comonomer.   The dye-sensitized photocell according to claim 1 or 2, wherein the metal oxide semiconductor is titanium oxide.   The dye-sensitized photocell according to claim 2, wherein colloidal titanium oxide is used in the production of the dye-containing microencapsulated metal oxide semiconductor particles.   The dye-sensitized photovoltaic cell according to claim 2, wherein a dye having a polymerizable reactive group is used in the preparation of the dye-containing microencapsulated metal oxide semiconductor particles.   The dye is at least one selected from organometallic complex dyes, pyridine dyes, phthalocyanine dyes, porphyrin dyes, cyanine dyes, merocyanine dyes, coumarin dyes, polymethine dyes, mercurochrome dyes, and eosin dyes. The dye-sensitized photocell according to claim 1, 2, or 6.   The dye-sensitized photocell according to claim 2, wherein the polymerizable surfactant is at least one selected from an anionic polymerizable surfactant, a cationic polymerizable surfactant, and a nonionic polymerizable surfactant.

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