JP2014143118A - Composition for photoelectric conversion element, and photoelectric conversion element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric conversion element having a photoelectric conversion layer with a plurality of hues.SOLUTION: On a conductive substrate, an ink (a) containing a semiconductor (e.g., titanium oxide particles), ionic polymer (e.g., a fluorine-based resin having a sulfo group, and the like), and a first coloring matter, and an ink (b) containing a semiconductor, ionic polymers, and a second coloring matter different from the first coloring matter, are separately coated. Then, a photoelectric conversion layer having a photoelectric conversion portion (A) and a photoelectric conversion portion (B) is formed without sintering the semiconductor.

Description

  The present invention is a photoelectric conversion layer constituting a photoelectric conversion element such as a solar cell (particularly a dye-sensitized solar cell), and a photoelectric conversion layer (multicolor photoelectric conversion layer) having a plurality of hues or a laminate thereof. Composition (ink, ink set) useful for forming a film, photoelectric conversion layer formed by this composition or a laminate thereof (electrode, photoelectrode), and photoelectric conversion provided with this photoelectric conversion layer or a laminate thereof It relates to an element.

  Solar cells are attracting attention as clean energy with a low environmental impact, and are practically used. At present, solar cells using crystalline silicon are widely used, but there are problems such as high power generation cost due to the use of high-purity silicon and low conversion efficiency for weak light such as indoors.

  In order to solve such problems, solar cells using organic materials for photoelectric conversion sites have been widely developed, and dye-sensitized solar cells are particularly attracting attention. The dye-sensitized solar cell has been developed by Graetzel et al. Of Lausanne University of Technology [for example, Japanese Patent No. 2664194 (Patent Document 1)], and a metal oxide semiconductor (such as titanium oxide) is added to the photoelectric conversion site. A major feature is the use of dyes.

  In such a dye-sensitized solar cell, since photoelectric conversion occurs at the contact interface between the metal oxide semiconductor and the sensitizing dye, it is desirable to increase the surface area of the metal oxide semiconductor in order to increase efficiency. For this reason, in the dye-sensitized solar cell, the effective area is increased with respect to the apparent area by using a nano-sized metal oxide semiconductor for the electrode.

  Note that the metal oxide nanoparticles simply peel off from the substrate with a slight impact and do not function as an electrode simply by being applied to the substrate. Moreover, since the electrical resistance between particles is large, the obtained electricity cannot be taken out efficiently, and conversion efficiency falls. For this reason, after apply | coating a metal oxide nanoparticle, it heat-processes by high temperature (about 500 degreeC), and the said subject is solved by melt-bonding between metal oxide nanoparticles. That is, in such a dye-sensitized solar cell, in order to avoid thermal decomposition of the dye, the photoelectric conversion layer is formed by adsorbing the dye by, for example, immersing the substrate in a solution containing the dye after the sintering process.

  On the other hand, the dye-sensitized solar cell has a hue corresponding to the type of the dye. It can also be assumed that design properties are imparted to the dye-sensitized solar cell using such a hue. For example, by forming an electrode in a predetermined design shape and forming a photoelectric conversion layer on the electrode, a solar cell having a hue (shadow) corresponding to the design shape portion can be obtained.

  However, in the conventional dye-sensitized solar cell, as described above, the formation of the photoelectric conversion layer requires a sintering process and an adsorption process of the dye after the sintering process. Only designs with one hue can be formed. In addition, a complicated process as a whole including the sintering process is required, which causes an increase in manufacturing cost. Furthermore, since it is necessary to expose the substrate to a high temperature, substrates that can be substantially used are limited to inorganic materials such as glass, and a flexible dye-sensitized solar cell using a plastic substrate cannot be produced.

Japanese Patent No. 2664194 (Claims)

  Accordingly, an object of the present invention includes an ink set (ink composition, combined ink, ink) capable of forming a photoelectric conversion layer having a plurality of hues (or colors), and a photoelectric conversion layer formed by the ink set. It is providing the laminated body (electrode), its manufacturing method, and a photoelectric conversion element provided with this laminated body.

  Another object of the present invention is to provide an ink set capable of forming a photoelectric conversion layer excellent in durability capable of maintaining photoelectric conversion characteristics over a long period of time, and a laminate (electrode) including a photoelectric conversion layer formed by this ink set. And a manufacturing method thereof, and a photoelectric conversion element provided with the laminate.

  Still another object of the present invention is to provide an ink set capable of forming a photoelectric conversion layer having high adhesion to a substrate, a laminate (electrode) including the photoelectric conversion layer formed by this ink set, and a method for producing the same. And it is providing the photoelectric conversion element provided with this laminated body.

  As a result of intensive studies to solve the above problems, the present inventors have found that a semiconductor (for example, titanium oxide particles), an ionic polymer (for example, a strongly acidic ion exchange resin), a dye (sensitizing dye), Surprisingly, by using a composition (ink) that combines the above, a photoelectric having sufficient photoelectric conversion characteristics (excellent semiconductor conductivity and excellent semiconductor-substrate conductivity) without sintering. Using the ability to form a conversion layer and the fact that such sintering is unnecessary, when a plurality of inks having different types of pigments (or hues) are used in combination (ie, as an ink set) ) And found that a (polychromatic) photoelectric conversion layer having a plurality of hues can be obtained, and the present invention was completed.

  That is, the ink set (composition, ink set composition) of the present invention is an ink set for forming a photoelectric conversion layer having a plurality of hues, and includes an ink containing a semiconductor, an ionic polymer, and a first dye. (A) (or composition (a)) and an ink (b) (or composition (b)) containing a semiconductor, an ionic polymer, and a second dye different from the first dye.

  In the ink (a) and the ink (b) constituting such an ink set, the semiconductor may be, for example, a metal oxide (for example, titanium oxide). The size of the semiconductor may be nano-sized, and the shape of the semiconductor may be particulate or fibrous. Preferred semiconductors include at least one selected from titanium oxide nanoparticles, zinc oxide nanoparticles, and tin oxide nanoparticles.

  In the ink (a) and the ink (b), the ionic polymer may be composed of an anionic polymer (particularly a strongly acidic ion exchange resin such as a fluorine-containing resin having a sulfo group).

  In the ink (a) and the ink “(b)”, the ratio of the ionic polymer may be, for example, about 0.05 to 20 parts by weight with respect to 1 part by weight of the semiconductor.

  A representative ink set of the present invention includes an ionic polymer in which the semiconductor is composed of titanium oxide nanoparticles and the ionic polymer is composed of a fluorine-containing resin having a sulfo group in the ink (a) and the ink (b). In addition, an ink set in which the ratio of the ionic polymer is 0.05 to 8 parts by weight with respect to 1 part by weight of the semiconductor is included.

  In ink (a) and ink (b), the ionic polymer may be composed of an anionic polymer having a pH of less than 7 at 25 ° C.

  Further, the ink (b) may be composed of a plurality of inks (or ink sets) different in colorant. That is, the ink (b) is composed of n kinds of inks (ink (b1), ink (b2)..., Ink (bn)), and the coloring matter (second coloring matter) contained in each ink is different. Ink may be used. By using such an ink (b), the ink set can be composed of three or more inks having different hues (a total of three or more inks (a) and an ink (b) containing two or more inks). Make up ink). Therefore, when such an ink set is used, a photoelectric conversion layer having three or more hues can be formed as will be described later.

  The present invention includes a photoelectric conversion layer formed from the composition (or ink set). Such a photoelectric conversion layer is usually obtained in the form of a laminate laminated on a substrate (particularly a conductive substrate). Specifically, the stacked body is a stacked body including a substrate (particularly a conductive substrate) and a photoelectric conversion layer stacked on the substrate and having a plurality of hues, and the photoelectric conversion layer is an ink. (A) [i.e., the photoelectric conversion site (A) formed with the ink (a) (or composition (a)) containing the semiconductor, the ionic polymer and the first pigment] and the ink (b) (or composition) (B)) [i.e., a photoelectric conversion site (B) formed of an ink (b) (or composition (b)) containing a semiconductor, an ionic polymer, and a second dye different from the first dye] It is a laminated body containing.

  In such a laminate, the photoelectric conversion site (A) and at least a part of the photoelectric conversion site (B) may be directly formed on the conductive substrate.

  In the laminate, the photoelectric conversion site (B) may be formed of an ink (b) composed of a plurality of inks different in colorant. In such a laminate, the photoelectric conversion sites (B) may form a plurality of photoelectric conversion sites having different hues. In this case, the photoelectric conversion layer may typically have three or more hues.

  In the laminate, the photoelectric conversion layer may have a thickness of about 0.1 to 100 μm.

  The present invention also includes a method for producing the laminate. That is, such a method can be performed on a substrate (especially a conductive substrate) with an ink (a) (or composition (a)) [ie, an ink (a) (including a semiconductor, an ionic polymer and a first dye) ( Or composition (a))] and ink (b) (or composition (b)) [ie, ink (b) (or composition comprising a semiconductor, an ionic polymer and a second dye different from the first dye). (B))] and a photoelectric conversion layer having a photoelectric conversion site (A) and a photoelectric conversion site (B) without sintering the semiconductor, This is a method for producing the laminate.

  The present invention further includes a photoelectric conversion element including the laminate (the laminate as an electrode). Such a photoelectric conversion element may be a solar cell (that is, a dye-sensitized solar cell). Such a dye-sensitized solar cell is, for example, a laminate composed of a photoelectric conversion layer containing a dye as an electrode, a counter electrode disposed to face the electrode, and interposed between these electrodes, and sealed. You may be comprised with the electrolyte layer by which the stop process was carried out.

  In the present specification, “a plurality of hues” includes a mixed color (or a mixed hue) obtained by stacking the photoelectric conversion site (A) and the photoelectric conversion site (B).

  In this invention, since a photoelectric converting layer can be formed without passing through a sintering process, the photoelectric converting layer which has several hues can be formed by using several ink (ink set) containing a mutually different pigment | dye. Moreover, such a photoelectric conversion layer has stable photoelectric conversion characteristics over a long period of time and does not have a sintering process, and is excellent in durability. It also has high adhesion to the substrate. Therefore, in the present invention, it is possible to use a plastic substrate as the substrate without exposing the substrate to a high temperature. When such a plastic substrate is used, a flexible electrode or a photoelectric conversion element can be obtained. Furthermore, since the sintering process is not performed, the manufacturing process of the photoelectric conversion layer can be simplified. Thus, in the present invention, it is possible to easily form a photoelectric conversion layer having a plurality of hues and having excellent design properties (design properties) without impairing the photoelectric conversion characteristics, even though the sintering process is not performed. Highly useful.

FIG. 1 is a plan view showing masks 1 and 2 used in the embodiment. FIG. 2 is a plan view showing the photoelectric conversion layers obtained in Examples 1 to 4. FIG. FIG. 3 is a plan view showing the photoelectric conversion layer obtained in Example 5. FIG. FIG. 4 is a diagram showing output characteristics of the dye-sensitized solar cells obtained in Examples 1 to 5. FIG. 5 is a diagram showing the open-circuit voltage before and after light irradiation of the dye-sensitized solar cell obtained in Example 5.

[Ink set (composition for photoelectric conversion layer)]
The ink set (ink composition, ink set composition) of the present invention includes an ink (a) (or composition (a)) containing a semiconductor, an ionic polymer, and a first dye, and a semiconductor, an ionic polymer, and a first dye. And at least ink (b) (or composition (b)) containing a second dye different from the one dye. As described later, such an ink set is particularly useful as an ink (ink set) for forming a photoelectric conversion layer having a plurality of hues (or a photoelectric conversion layer constituting a photoelectric conversion element). That is, by using each ink of such an ink set individually, a photoelectric conversion layer having a plurality of hues can be formed as described later. The ink (b) does not have to be a single type of ink, and may be composed of a plurality of inks (or ink sets) that differ in color (or hue), as will be described later. As described above, when the ink (b) is composed of a plurality of inks (or inks), a photoelectric conversion layer having hues (or colors) of three colors (or three types) or more can be formed.

(semiconductor)
Ink (a) (or composition (a), first ink (a), ink composition (a), the same shall apply hereinafter) and ink (b) (or composition (b), second ink (b In the ink composition (b), the same shall apply hereinafter), the semiconductors can be broadly classified into inorganic semiconductors and organic semiconductors. In the present invention, inorganic semiconductors can be suitably used. The inorganic semiconductor may be an inorganic substance having semiconductor characteristics, and can be appropriately selected according to the application. Examples thereof include a metal simple substance and a metal compound (metal oxide, metal sulfide, metal nitride, etc.).

  Examples of the metal constituting the inorganic semiconductor include Group 2 metals (for example, calcium, strontium, etc.), Group 3 metals (for example, scandium, yttrium, lanthanoids, etc.), Group 4 metals (for example, scandium, yttrium, etc.). For example, titanium, zirconium, hafnium, etc.), periodic table group 5 metals (eg, vanadium, niobium, tantalum, etc.), periodic table group 6 metals (eg, chromium, molybdenum, tungsten, etc.), periodic table group 7 metals. (For example, manganese), periodic table group 8 metal (for example, iron), periodic table group 9 metal (for example, cobalt), periodic table group 10 metal (for example, nickel), periodic table 11th Group metal (eg, copper), Periodic Table Group 12 metal (eg, zinc, cadmium, etc.), Periodic Table Group 13 metal (eg, aluminum, Lithium, indium, thallium, etc.), periodic table group 14 metals (eg, germanium, tin, etc.), periodic table group 15 metals (eg, arsenic, antimony, bismuth, etc.), periodic table group 16 metals (eg, tellurium) Etc.).

  The semiconductor may be a compound containing these metals alone or a compound containing a combination of these metals. For example, the semiconductor may be an alloy, and the metal oxide may be a complex oxide. Further, the semiconductor may contain a combination of the above metal and another metal (such as an alkali metal).

Specific semiconductors include, for example, metal oxides {for example, transition metal oxides [for example, periodic table group 3 metal oxides (yttrium oxide, cerium oxide, etc.), periodic table group 4 metal oxides (titanium oxide]. , Zirconium oxide, calcium titanate, strontium titanate, etc.), periodic table group 5 metal oxides (vanadium oxide, niobium oxide, tantalum oxide (such as ditantalum pentoxide)), periodic table group 6 metal oxides ( Chromium oxide, tungsten oxide, etc.), periodic table group 7 metal oxides (manganese oxide, etc.), periodic table group 8 metal oxides (iron oxide, ruthenium oxide, etc.), periodic table group 9 metal oxides (cobalt oxide) , Iridium oxide, complex oxide of cobalt and sodium, etc.), periodic table group 10 metal oxides (such as nickel oxide), periodic table group 11 metal oxides (acid) Copper, etc.), periodic table group 12 metal oxides (such as zinc oxide)], typical metal oxides [for example, periodic table group 2 metal oxides (such as strontium oxide), periodic table group 13 metal oxides ( Gallium oxide, indium oxide, etc.), periodic table group 14 metal oxides (silicon oxide, tin oxide, etc.), periodic table group 15 metal oxides (such as bismuth oxide), etc.], complex oxides containing a plurality of these metals [For example, complex oxide of Group 11 metal of the periodic table and transition metal (transition metal other than Group 11 metal of the periodic table) (for example, complex oxide of copper such as CuYO ₂ and Group 3 metal of the periodic table) , Complex oxides of Group 11 metals and typical metals of the periodic table (for example, complex oxides of Cu and Periodic Group 13 metals such as CuAlO ₂ , CuGaO ₂ , and CuInO ₂ ; copper and periods such as SrCu ₂ O ₂ Table Group 2 metals Such as a composite oxide of silver and the periodic table group 13 metal such AgInO _2), etc.], the plurality of metals and oxides including periodic table Group 16 element other than oxygen [e.g., period; composite oxides Compound oxysulfide (for example, compound oxysulfide of copper and periodic table group 3 metal such as LaCuOS) of a group 11 metal and a transition metal (transition metal other than the group 11 metal of the periodic table), periodic table Compound acid selenide of Group 11 metal and transition metal (transition metal other than Group 11 metal of the periodic table) (for example, complex acid selenide of copper such as LaCuOSe and Group 3 metal of the periodic table) etc.] etc.} , Metal nitrides (such as thallium nitride), metal phosphides (such as InP), metal sulfides {for example, Cds, copper sulfide (CuS, Cu ₂ S), composite sulfides [for example, periodic table Group 11 metals and typical Complex sulfides with metals (eg C complex sulfides of copper and group 13 metals of the periodic table such as uGaS ₂ and CuInS ₂ ), etc.}, metal selenides (CdSe, ZnSe, etc.), metal halides (CuCl, CuBr, etc.), group 13 metals of the periodic table -Metal compounds (or alloys) such as Group 15 metal compounds (GaAs, InSb, etc.), Periodic Table Group 12 metals-Group 16 metal compounds (CdTe, etc.); Metal simple substance (eg, palladium, platinum, silver, gold) , Silicon, germanium) and the like.

  The semiconductor may be a semiconductor doped with other elements.

  The semiconductor may be an n-type semiconductor or a p-type semiconductor.

  Among the above-exemplified semiconductors (particularly inorganic semiconductors), typical n-type semiconductors include, for example, a periodic table group 4 metal oxide (such as titanium oxide) and a periodic table group 5 metal oxide (niobium oxide, oxide). Tantalum, etc.), periodic table group 12 metal oxides (such as zinc oxide), periodic table group 13 metal oxides (such as gallium oxide and indium oxide), periodic table group 14 metal oxides (such as tin oxide), etc. Can be mentioned.

Typical p-type semiconductors include, for example, a periodic table group 6 metal oxide (such as chromium oxide), a periodic table group 7 metal oxide (such as manganese oxide), and a periodic table group 8 metal oxide (such as manganese oxide). Iron oxide), periodic table group 9 metal oxides (cobalt oxide, iridium oxide, etc.), periodic table group 10 metal oxides (such as nickel oxide), periodic table group 11 metal oxides (such as copper oxide), Periodic table Group 15 metal oxides (such as bismuth oxide), complex oxides of Group 11 metals and transition metals or typical metals (for example, CuYO ₂ , CuAlO ₂ , CuGaO ₂ , CuInO ₂ , SrCu ₂ O _2). , AgInO _2, etc.), complex oxysulfides (for example, LaCuOS) of Group 11 metals and transition metals of the periodic table, and complex acid selenides (for example, LaCuOSe) of Group 11 metals of the periodic table and transition metals Etc.), and composite sulfides (for example, CuGaS ₂ , CuInS _2, etc.) of Group 11 metals of the periodic table and typical metals.

  These semiconductors may be used alone or in combination of two or more.

Among these, preferable semiconductors include metal oxides, and transparent metal oxides (transparent metal oxides) are particularly preferable. Examples of such metal oxides include titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), gallium oxide (Ga ₂ O ₃ ), and copper-aluminum. Examples thereof include oxides (CuAlO ₂ ), iridium oxide (IrO), nickel oxide (NiO), and doped bodies of these metal oxides. Among these, titanium oxide, zinc oxide, tin oxide and the like are preferable.

Of the semiconductors, an n-type semiconductor may be preferably used. In particular, in the present invention, an n-type metal oxide semiconductor such as titanium oxide (TiO ₂ ) may be preferably used.

  The crystal form (crystal form) of titanium oxide may be any of a rutile type (goldenite type), anatase type (hypopyrite type), or brookite type (plate titanium stone type). In the present invention, rutile type or anatase type titanium oxide can be suitably used. When anatase type titanium oxide is used, it is easy to maintain high adhesion of the semiconductor to the substrate over a long period of time. On the other hand, rutile-type titanium oxide is easy to be oriented and can make a contact area between titanium oxides relatively large, and therefore may be suitably used from the viewpoint of conductivity and durability.

  The titanium oxide may be titanium oxide doped with other elements.

  The shape of the semiconductor (for example, a metal oxide such as titanium oxide) is not particularly limited, and may be in the form of particles, fibers (or needles or rods), plates, and the like. A preferable shape is a particle shape or a needle shape, and a particulate semiconductor (semiconductor particle) is particularly preferable.

  The average particle size (average primary particle size) of the semiconductor particles can be selected from a range of about 1 to 1000 nm (for example, 1 to 700 nm), and is usually nano size (nanometer size), for example, 1 to 500 nm (for example, 2 to 2 nm). 400 nm), preferably 3 to 300 nm (eg 4 to 200 nm), more preferably 5 to 100 nm (eg 6 to 70 nm), especially 50 nm or less [eg 1 to 50 nm (eg 2 to 40 nm), preferably 3 To 30 nm (for example, 4 to 25 nm), more preferably 5 to 20 nm (for example, 6 to 15 nm, usually 10 to 50 nm).

  In the needle-like (or fibrous) semiconductor, the average fiber diameter may be, for example, 1 to 300 nm, preferably 10 to 200 nm, and more preferably about 50 to 100 nm. In the needle-like semiconductor, the average fiber length may be about 10 to 2000 nm, preferably about 50 to 1000 nm, and more preferably about 100 to 500 nm. In an acicular semiconductor, the aspect ratio may be, for example, about 2 to 200, preferably about 5 to 100, and more preferably about 20 to 40.

Semiconductor (e.g., fibrous or particulate semiconductor) specific surface area of, depending to the shape, for example, 1~600m ² / g, preferably 2~500m ² / g, more preferably 3~400m ² / It may be about g.

In particular, the specific surface area of the semiconductor particles is, for example, 5 to 600 m ² / g (for example, 7 to 550 m ² / g), preferably 10 to 500 m ² / g (for example, 15 to 450 m ² / g), and more preferably. 20 to 400 m ² / g (e.g., 30~350m ² / g), in particular ^{50 m} 2 / g or more [e.g., 50~500m ² / g, preferably 70~450m ² / g, more preferably 100 to 400 m ² / g, particularly 150 to 350 m ² / g (for example, 200 to 350 m ² / g)].

The specific surface area of the fibrous or needle-like semiconductor is about 1 to 100 m ² / g, preferably ² to 70 m ² / g, and more preferably about 3 to 50 m ² / g (for example, 4 to 30 m ² / g). It may be.

  A semiconductor (such as titanium oxide) may be mixed with an ionic polymer (and a dye described later) as a dispersion (such as an aqueous dispersion). As the semiconductor, a commercially available product may be used, or a semiconductor synthesized using a conventional method may be used. For example, a dispersion of titanium oxide can be obtained by the method described in Japanese Patent No. 452886.

  Ink (a) and ink (b), the semiconductors may be the same or different.

(Ionic polymer)
The present invention is characterized by combining (compositing) a semiconductor and an ionic polymer. With such a combination, a photoelectric conversion layer having excellent photoelectric conversion characteristics can be formed without sintering. The reason for this is not clear, but the combination of an ionic polymer and a semiconductor [particularly nano-sized semiconductor particles (semiconductor nanoparticles)] can improve the dispersion stability of the semiconductor, and can effectively exhibit semiconductor characteristics, Depending on the type of ionic polymer, it may be considered that the ionic polymer itself also functions as an electrolyte (solid electrolyte) that transports charges generated by photoelectric conversion.

  Moreover, in this invention, since an ionic polymer acts like a binder, such a photoelectric conversion characteristic can be hold | maintained over a long period of time, and sufficient adhesiveness with respect to the board | substrate of a photoelectric converting layer (or semiconductor) can also be ensured.

  Furthermore, in the present invention, a photoelectric conversion layer having both a photoelectric conversion function and a power storage function (a so-called electric double layer or a photoelectric conversion layer having a function as a capacitor) can be obtained. When forming a photoelectric conversion layer having such a power storage function, an ionic polymer may be selected according to the type of semiconductor. That is, (i) when the semiconductor is an n-type semiconductor, an ionic polymer composed of an anionic polymer is selected, and (ii) when the semiconductor is a p-type semiconductor, an ionic polymer composed of a cationic polymer A polymer may be selected. By such a combination of a semiconductor and an ionic polymer, the reason is not clear, but an excellent power storage function can be efficiently imparted to the photoelectric conversion layer.

  In the ink (a) and the ink (b), the ionic polymer (ionic polymer) may be a polymer having ionicity (electrolyte) (that is, a polymer electrolyte), and may be an anionic polymer or a cationic polymer. {For example, a polymer having an amino group or a substituted amino group [for example, an allylamine polymer (such as polyallylamine)], a polymer having a quaternary ammonium base (for example, a quaternary ammonium to a styrene-divinylbenzene copolymer) A polymer introduced with a base, etc.)} or an amphoteric polymer (such as a polymer having both a carboxyl group and an amino group). In the present invention, an anionic polymer, a cationic polymer (especially an anion) A suitable polymer). An anionic polymer or a cationic polymer seems to act suitably as a binder because it is likely to be immobilized by bonding (chemical bond, hydrogen bond, etc.) to the surface of a semiconductor (such as titanium oxide). In particular, the ionic polymer may be an ion exchange resin (or an ion exchanger or a solid polymer electrolyte).

  The anionic polymer is usually a polymer having an acid group [carboxyl group, sulfo group (or sulfonic acid group, etc.)]. The anionic polymer may have an acid group (or acidic group) alone or in combination of two or more. In addition, the acid group may be partially or entirely neutralized.

  As typical anionic polymers [or cation exchange resins (cationic ion exchange resins, acid ion exchange resins)], for example, strong acid cation exchange resins, weak acid cation exchange resins {for example, carboxyl groups An ion exchange resin [for example, (meth) acrylic acid polymer (for example, poly (meth) acrylic acid; (meth) acrylic acid such as methacrylic acid-divinylbenzene copolymer, acrylic acid-divinylbenzene copolymer, and other copolymerizable monomers A copolymer with a monomer (such as a crosslinkable monomer), a fluorine-containing resin having a carboxyl group (perfluorocarboxylic acid resin), and the like].

  Among these, preferred anionic polymers include strongly acidic cation exchange resins. Examples of the strongly acidic ion exchange resin include a fluorine-containing resin having a sulfo group {for example, a copolymer of a fluoroalkene and a sulfofluoroalkyl-fluorovinyl ether [for example, tetrafluoroethylene- [2- (2-sulfotetrafluoro Ethoxy) hexafluoropropoxy] trifluoroethylene copolymer (for example, graft copolymer) etc.], etc.], styrene resin having a sulfo group [for example, Polystyrene sulfonic acid, a sulfonated product of a crosslinked styrene-based polymer (for example, a sulfonated product of a styrene-divinylbenzene copolymer), and the like.

  A fluorine-containing resin having a sulfo group is available from DuPont under the trade name “Nafion” series.

  When the ionic polymer is composed of an anionic polymer, the ionic polymer may be composed of only an anionic polymer, or an anionic polymer may be combined with another ionic polymer (for example, an amphoteric polymer). Good. In such a case, the ratio of the anionic polymer to the whole ionic polymer is, for example, 30% by weight or more (for example, 40 to 99% by weight), preferably 50% by weight or more (for example, 60 to 98% by weight), It may be preferably 70% by weight or more (for example, 80 to 97% by weight).

  The cationic polymer is usually a polymer having a basic group (alkaline group). As the basic group, for example, an amino group [eg, primary, secondary or tertiary amino group such as amino group, substituted amino group (for example, mono or dialkylamino group such as dimethylamino group)], And imino groups (—NH—, —N <), quaternary ammonium bases (eg, trialkylammonium bases such as trimethylammonium base), and the like. The cationic polymer may have these basic groups alone or in combination of two or more. In addition, the basic group may be partially or completely neutralized.

Typical cationic polymers [or anion exchange resins (anion type ion exchange resins, base type ion exchange resins)] include, for example, amine polymers {eg, allylamine polymers [polyallylamine, allylamine-dimethylallylamine copolymer A single or copolymer of allylamine monomers (eg, allylamine, diallylamine, diallylalkylamine (diallylmethylamine, diallylethylamine, etc.)) such as a copolymer, diallylamine-sulfur dioxide copolymer, etc. Not only a copolymer of a polymer, but also a copolymer of an allylamine monomer and a copolymerizable monomer, the same shall apply hereinafter)], a vinylamine polymer (for example, a vinylamine such as polyvinylamine) Monomers or copolymers), amino (Meth) acrylic polymers having a [for example, N-mono or dialkyl such as aminoalkyl (meth) acrylate (for example, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate) Amino C _1-4 alkyl (meth) acrylate), aminoalkyl (meth) acrylamide (for example, N-mono or dialkylamino C _1-4 alkyl (meth) acrylamide such as N, N-dimethylaminoethyl (meth) acrylamide) A (meth) acrylic monomer having an amino group such as a homopolymer or a copolymer], a heterocyclic amine polymer [for example, an imidazole polymer (for example, polyvinylimidazole), a pyridine polymer (for example, polyvinyl). Pyridine), pyrrolide Polymer such as polyvinyl pyrrolidone], amine-modified epoxy resin, amine-modified silicone resin, etc.], imine polymer [for example, polyalkyleneimine (eg, polyethyleneimine etc.) or other imine monomers alone or Copolymer] and a quaternary ammonium base-containing polymer.

  In the quaternary ammonium base-containing polymer, the salt is not particularly limited, and examples thereof include halide salts (for example, chloride, bromide, iodide, etc.), carboxylates (for example, alkane salts such as acetate). And sulfonates.

As the quaternary ammonium base-containing polymer, for example, a polymer obtained by quaternizing an amino group or imino group of the amine-based polymer or imine polymer exemplified above {for example, N, N, N-trialkyl-N -(Meth) acryloyloxyalkylammonium salts [for example, tri-C ₁ such as trimethyl-2- (meth) acryloyloxyethylammonium chloride, N, N-dimethyl-N-ethyl-2- (meth) acryloyloxyethylammonium chloride, etc. _-10 alkyl (meth) acryloyloxy _C2-4 alkylammonium salt] or a copolymer}, vinylaralkylammonium salt-based polymer {for example, vinylaralkylammonium salt [for example, N, N, N-trialkyl -N- (vinyl aralkyl) Ammonium salts (for example, trimethyl-p-vinylbenzylammonium chloride, N, N-dimethyl-N-ethyl-p-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ) Tri-C _1-10 alkyl (vinyl-C _6-10 aryl C _1-4 alkyl) ammonium salt such as ethylammonium chloride), N, N-dialkyl-N-aralkyl-N- (vinylaralkyl) ammonium salt (eg , N, N, such as N- dimethyl -N- benzyl -p- vinylbenzyl ammonium chloride, N- di _{C 1-10} alkyl _{-N-C 6-10} aryl _{C 1-4} alkyl -N- (vinyl -C _{6 -10} aryl _{C 1-4} alkyl) a homo- or copolymer of an ammonium salt), etc.}, Kachio Cellulose [e.g., hydroxy group-containing cellulose derivatives (e.g., hydroxy C _2-4 alkyl cellulose such as hydroxyethyl cellulose) and the quaternary ammonium salt (e.g., trialkyl ammonium bases) epoxy compound having a (e.g., N, N , N-trialkyl-N-glycidylammonium salt), and polymers obtained by introducing a quaternary ammonium base into a styrene-divinylbenzene copolymer.

  Cationic cellulose (cationized cellulose) is from Daicel Co., Ltd. under the trade name “Gerner”, polyallylamine is from Nito-Bo Medical Co., Ltd. under the trade name “PAA”, and amine-modified silicone resins are from Shin-Etsu Chemical Co., Ltd. It can be obtained from Co., Ltd. as the product name “KF” series.

  Preferred cationic polymers include strongly basic cationic polymers (anion exchange resins) such as quaternary ammonium base-containing polymers.

  When the ionic polymer is composed of a cationic polymer, the ionic polymer may be composed of only a cationic polymer, or a combination of a cationic polymer and another ionic polymer (for example, an amphoteric polymer). Good. In such a case, the ratio of the cationic polymer to the whole ionic polymer is, for example, 30% by weight or more (for example, 40 to 99% by weight), preferably 50% by weight or more (for example, 60 to 98% by weight), It may be preferably 70% by weight or more (for example, 80 to 97% by weight).

  The ionic polymer may be any of acidic, neutral and alkaline, and its pH is not particularly limited. In addition, you may select pH of an ionic polymer according to the desired characteristic provided to a photoelectric converting layer. For example, although depending on the type of the dye, it is preferable to relatively reduce the pH in that the photoelectric conversion characteristics can be efficiently maintained over a long period of time. In such a case, for example, the pH (25 ° C.) of the ionic polymer can be selected from a range of 10 or less (for example, 0.1 to 8), for example, less than 7 (for example, 0.15 to 6.5). , Preferably 6 or less (eg 0.2 to 5), more preferably 4 or less (eg 0.3 to 3), especially 2 or less (eg 0.5 to 1.5), usually 3 or less (eg 1 to 3). When an anionic polymer (or an ionic polymer composed of an anionic polymer) is selected as the ionic polymer, such a relatively low pH is preferable from the viewpoint of imparting a power storage function.

  It may be preferable to use an ionic polymer having a relatively high pH. Depending on the type of semiconductor, by using an ionic polymer with a relatively high pH, the aggregation of semiconductors (eg, titanium oxide nanoparticles) can be effectively suppressed, or the photoelectric conversion characteristics can be further improved. There is. Moreover, the adhesiveness with respect to a board | substrate may be improved efficiently. The pH (25 ° C.) of such an ionic polymer is, for example, 3 or more (for example, 4 to 14), preferably 5 or more (for example, 6 to 14), and more preferably 7 or more (for example, 7 to 14). It may be a degree.

  In particular, the pH (25 ° C.) of an anionic polymer (for example, a strongly acidic ion exchange resin) or an anionic polymer is 3 or more (for example, 4 to 14), preferably 5 or more ( For example, it may be 5 to 13), more preferably 6 or more (for example, 6.5 to 12), particularly 7 or more (for example, 7 to 12), and usually 6 to 14 (for example, 6.5 to 11). , Preferably about 7-9).

  When the pH is relatively large, the pH (25 ° C.) of the cationic polymer (for example, strongly basic anion exchange resin) or the ionic polymer composed of the cationic polymer is 5 or more (for example, 6 to 6). 14), for example, 7 or more (for example, 7.5 to 14), preferably 8 or more (for example, 8.5 to 14), and more preferably 9 or more (for example, 9.5 to 13). 5), especially 10 or more (for example, 10.5 to 13). As described above, when a cationic polymer having a relatively high pH (or an ionic polymer composed of an anionic polymer) is selected as the ionic polymer, it is also preferable from the viewpoint of imparting a power storage function.

  The pH may be a value in an aqueous solution or aqueous dispersion of an ionic polymer (or a value in a solvent containing water). The pH can be adjusted by a conventional method (for example, a method of neutralizing an acid group with an appropriate base or a method of neutralizing a basic group with an appropriate acid group). In the neutralized acid group, the counter ion is not particularly limited, and may be, for example, an alkali metal (for example, sodium, potassium, etc.).

  In addition, an ionic polymer (anionic polymer etc.) may have a crosslinked structure (for example, a sulfonated product of the above-mentioned (meth) acrylic acid-divinylbenzene copolymer or styrene polymer), and a crosslinked structure. May not be included. In the present invention, in particular, an ionic polymer having no crosslinked structure (or having a very low degree of crosslinking) may be suitably used.

  In the ionic polymer (ion exchange resin), the ion exchange capacity is 0.1 to 5.0 meq / g (for example, 0.15 to 4.0 meq / g), preferably 0.2 to 3.0 meq / g ( For example, it may be 0.3 to 2.0 meq / g), more preferably 0.4 to 1.5 meq / g, particularly about 0.5 to 1.0 meq / g.

  The molecular weight of the ionic polymer is not particularly limited as long as it can be dissolved or dispersed in the solvent.

  The ionic polymers may be used alone or in combination of two or more.

  The proportion of the ionic polymer can be selected from the range of 0.01 parts by weight or more (for example, 0.02 to 100 parts by weight) with respect to 1 part by weight of the semiconductor, for example, 0.03 parts by weight or more (for example, 0 0.04 to 50 parts by weight), preferably 0.05 parts by weight or more (eg 0.05 to 20 parts by weight), more preferably 0.07 parts by weight or more (eg 0.08 to 15 parts by weight), usually 0.03 to 10 parts by weight [eg, 0.05 to 8 parts by weight (eg, 0.06 to 7 parts by weight), preferably 0.07 to 5 parts by weight (eg, 0.08 to 3 parts by weight), More preferably, it may be about 0.1 to 2 parts by weight (for example, 0.1 to 1 part by weight)]. By combining the semiconductor and the ionic polymer at the above ratio, a photoelectric conversion layer having excellent photoelectric conversion characteristics can be efficiently formed. Moreover, the point of the viscosity reduction of a composition and the point of making a color vivid are also suitable. In addition, when there is too little quantity of an ionic polymer, sufficient adhesiveness may not be obtained in connection with the dispersibility of a semiconductor not being improved. On the other hand, if the amount is too large, contact between semiconductors tends to be hindered, and the photoelectric conversion characteristics may be deteriorated.

  In the ink (a) and the ink (b), the ionic polymers may be the same or different.

(Dye)
In the ink (a) and the ink (b), a component (or a sensitizing action) functioning as a sensitizer (sensitizing dye, photosensitizing dye) is used as the coloring matter (first coloring matter, second coloring matter). Component), for example, organic dyes, inorganic dyes (for example, carbon pigments, chromate pigments, cadmium pigments, ferrocyanide pigments, metal oxide pigments, silicate pigments) Pigments, phosphate pigments, etc.). The dyes may be used alone or in combination of two or more.

  Examples of organic dyes (organic dyes or organic pigments) include ruthenium complex dyes {for example, ruthenium bipyridine complexes [for example, cis-bis (isothiocyanato) bis (2,2′-bipyridyl-4,4′-dicarboxylate]. ) Ruthenium (II) bistetrabutylammonium (also known as N719), cis-bis (isothiocyanato) (2,2′-bipyridyl-4,4′-dicarboxylato) (2,2′-bipyridyl-4,4 ′) -Dinonyl) ruthenium (II), cis-bis (isothiocyanato) bis (2,2'-bipyridyl-4,4'-dicarboxylato) ruthenium (II), cis-bis (cyanide) (2,2'-bipyridyl -4,4'-dicarboxylato) ruthenium (II), tris (2,2'-bipyridyl-4,4'-dicarboxyla ) Ruthenium (II) dichloride, etc.], terpyridine complexes of ruthenium [e.g., tris (isothiocyanato) ruthenium (II) -2,2 ′: 6 ′, 2 ″ -terpyridine-4,4 ′, 4 ″ -tricarboxylic acid Ruthenium pyridine complex such as tristetrabutylammonium salt], osmium complex dye, porphyrin dye (magnesium porphyrin, zinc porphyrin etc.), chlorophyll dye (chlorophyll etc.), xanthene dye (rhodamine B, sulforhodamine B) Erythrosine), cyanine dyes (merocyanine, quinocyanine, cryptocyanine, etc.), phthalocyanine dyes, azo dyes, perylene dyes, perinone dyes, coumarin dyes, quinone dyes, anthraquinone dyes, squarily Um dyes, azomethine dyes, quinophthalone dyes, quinacridone dyes, isoindoline dyes, nitroso dyes, pyrrolopyrrole dyes, xanthene dyes, carbazole dyes, indoline dyes, basic dyes (methylene blue, basic blue) 12) and the like.

  In addition, the 1st pigment | dye and the 2nd pigment | dye should just be a pigment | dye from which a hue mutually differs. The hue (or color) of the pigment is not particularly limited, and may be any of black, white, yellow, blue, red, green, and the like. Further, as long as the first dye and the second dye are different from each other in hue, the first dye and / or the second dye may be composed of two or more kinds of dyes. When two or more kinds of pigments are used in a single composition (or ink), they can be mixed colors.

  Further, when the second pigment is composed of a plurality of pigments, the ink (b) may be a single ink containing a semiconductor, an ionic polymer, and a plurality of pigments, and a plurality of different inks for each pigment. There may be. For example, when the second dye is composed of dye 1, dye 2 and dye 3 that are different in hue from each other, the ink (b) is an ink (b1) containing a semiconductor, an ionic polymer and the dye 1, a semiconductor, The ink (b2) containing the ionic polymer and the dye 2 and the ink (b3) containing the semiconductor, the ionic polymer and the dye 3 may be used (or three ink sets may be used). ). Thus, by making the ink (b) two or more inks, a photoelectric conversion layer having three or more hues can be formed together with the ink (a).

  In addition, a pigment | dye is normally contained in a photoelectric converting layer (or photoelectric conversion element) with the form adhering (or fix | immobilized) to the semiconductor (or semiconductor surface). Examples of adhesion (or immobilization) include adsorption (physical adsorption) and chemical bonding. Therefore, the dye may be suitably selected as a dye that easily adheres to the semiconductor. A dye having a functional group such as a carboxyl group, an ester group, or a sulfo group as a ligand (for example, a ruthenium dye having a carboxyl group such as N719) is also preferable. A dye having such a ligand is preferable because it easily binds to a semiconductor surface such as titanium oxide and does not easily desorb.

  The ratio of the dye (adhesion or adsorption ratio) is not particularly limited, but may be selected so as to be in the range of the following formula in relation to the semiconductor and the ionic polymer, for example.

_{0 <(I A × I S} + D A × D S) / S S ≦ 1
(Wherein, I _A is the number of ionic groups in the ionic polymer, I _S is the area occupied per one ionic group, D _A dye (the number of dye molecules), D _S is the per dye Occupied area, S _S indicates the surface area of the semiconductor.)
In the above formula, I _A is the total number of ionic groups, for example, can be determined by multiplying the weight (g) and Avogadro number of ionic polymer to the ion exchange capacity of the ionic polymer (meq / g), Usually, I _A × I _S <S _S. I _S, D _S, respectively, an ionic group one occupied area (m ^2), a occupation area of the dye molecule (m ^2), may be a value when the area is projected to be the largest .

  In the composition (a) and the composition (b), the ratio of specific dyes (first dye, second dye) is, for example, 0.001 to 1 part by weight with respect to 1 part by weight of the semiconductor. Preferably it may be about 0.005 to 0.5 parts by weight, more preferably about 0.01 to 0.1 parts by weight (for example, 0.02 to 0.05 parts by weight).

  The ink (a) and the ink (b) may be a composition containing a solvent (coating composition). The solvent is not particularly limited, and is an organic solvent [for example, alcohol solvents (for example, alkanols such as methanol, ethanol, isopropanol, butanol), aromatic solvents (for example, aromatic hydrocarbons such as toluene and xylene). ), Ester solvents (eg, acetate esters such as ethyl acetate, butyl acetate, propylene glycol monomethyl ether monoacetate), ketone solvents (eg, chain ketones such as acetone; cyclic ketones such as cyclohexanone), ether Solvents (for example, chain ethers such as propylene glycol monomethyl ether and diethylene glycol dimethyl ether; cyclic ethers such as dioxane and tetrahydrofuran), halogen solvents (for example, halogenated solvents such as dichloromethane and chloroform) Cans), nitrile solvents (e.g., acetonitrile, and benzonitrile), nitro solvents (e.g., nitrobenzene etc.), etc.], and water. The solvents may be used alone or in combination of two or more.

  In the ink containing the solvent (ink (a) and / or ink (b)), the ratio of the solid content (or the non-volatile component) can be appropriately selected according to the coating method when forming the photoelectric conversion layer, for example, 0.1 to 90% by weight (for example, 0.5 to 70% by weight), preferably 1 to 50% by weight (for example, 5 to 40% by weight), and more preferably about 10 to 30% by weight. Good. In the present invention, since the proportion of the ionic polymer can be relatively increased, the dispersion stability of the semiconductor can be sufficiently ensured even if the solid content including the semiconductor is high.

  Moreover, the pH of the composition containing a solvent is not specifically limited, It can select from the range similar to the pH of an ionic polymer. Depending on the desired properties, the pH of the composition containing the solvent may be adjusted in the same range as the pH of the ionic polymer.

  The ink set of the present invention only needs to contain the ink (a) containing the first pigment and the ink (b) containing the second pigment, and the ink (b) is as described above. Furthermore, it may be a plurality of inks (ink sets) including pigments (second pigments) of different hues.

  That is, when the ink (b) is a plurality of inks, the coloring matter constituting each ink is different from the first coloring matter and different from each other. When the ink (b) is composed of a plurality of inks, in each ink, components other than the pigment (semiconductor, ionic polymer, etc.) may be the same or different, and a suitable mode (ratio) The same applies to each ink.

  Each ink constituting the ink set of the present invention can be obtained by mixing constituent components (semiconductor, ionic polymer, dye, etc.). For example, an ink containing a solvent may be prepared by mixing components in a solvent, and after mixing components (for example, a semiconductor, an ionic polymer, and a dye) in advance, the components are mixed (or dispersed) in the solvent. May be prepared. Also, a composition (mixture) containing some constituent components (eg, semiconductor and ionic polymer) and a composition (mixture solution) containing the remaining constituent components (eg, pigment) are separately prepared and mixed. May be prepared. As described above, when adjusting the pH of the ink, the pH can be adjusted at an appropriate stage. For example, the pH in the semiconductor dispersion is adjusted in advance to be within the above range, and the ion is adjusted. The composition may be mixed with an ionic polymer and a dye, and the pH of the composition may be adjusted in a mixed system of a semiconductor (or a dispersion thereof), an ionic polymer and a dye.

  The ink set of the present invention is useful as an ink set for forming a photoelectric conversion layer having a plurality of hues (or a photoelectric conversion layer constituting a photoelectric conversion element). Such a photoelectric conversion layer is usually formed on a substrate. That is, the photoelectric conversion layer constitutes a laminate together with the substrate. Below, a photoelectric converting layer and its manufacturing method are explained in full detail.

[Laminated body and manufacturing method thereof]
The laminate of the present invention includes a substrate and a photoelectric conversion layer (a photoelectric conversion layer formed from the ink set) stacked on the substrate. The photoelectric conversion layer includes a photoelectric conversion site (A) formed of the ink (a) and a photoelectric conversion site (B) configured of the ink (b), and a plurality of hues (or mixed colors). Hue).

  The substrate may be a conductive substrate, although it depends on the application. The conductive substrate may be composed of only a conductor (or a conductor layer), but usually a substrate in which a conductor layer (or a conductive layer or a conductive film) is formed on a base substrate (base substrate). Etc. In such a case, the photoelectric conversion layer is formed on the conductor layer.

  The conductor (conductive agent) can be appropriately selected depending on the application. For example, a conductive metal oxide [for example, tin oxide, indium oxide, zinc oxide, antimony-doped metal oxide (such as antimony-doped tin oxide), Tin-doped metal oxide (such as tin-doped indium oxide), aluminum-doped metal oxide (such as aluminum-doped zinc oxide), gallium-doped metal oxide (such as gallium-doped zinc oxide), fluorine-doped metal oxide (such as fluorine-doped tin oxide) ) And the like]. These conductors may be used alone or in combination of two or more. In addition, a transparent conductor may be sufficient as a conductor normally.

  As the base substrate, an inorganic substrate (for example, glass), an organic substrate [for example, polyester resin (for example, polyethylene terephthalate, polyethylene naphthalate), polycarbonate resin, cycloolefin resin, polypropylene resin, cellulose resin (cellulose) Triacetate, etc.), polyether resins (polyethersulfone, etc.), polysulfide resins (polyphenylene sulfide, etc.), substrates or films (plastic substrates or plastic films) formed of plastics such as polyimide resins, etc.]. In the present invention, since a semiconductor sintering step is unnecessary, a plastic substrate (plastic film) can be used as the base substrate.

  The photoelectric conversion layer can be formed by applying (or coating) ink (a) and ink (b) on a substrate (conductor layer), respectively. That is, the photoelectric conversion site (A) is formed at the site coated with the ink (a), and the photoelectric conversion site (B) is formed at the site coated with the ink (b).

  Such a photoelectric conversion layer can form a photoelectric conversion site | part (A) and a photoelectric conversion site | part (B) according to a desired design (corresponding | compatible). That is, if the photoelectric conversion layer includes the photoelectric conversion site (A) and the photoelectric conversion site (B) (that is, the photoelectric conversion layer (A) and the photoelectric conversion site (B) together form a photoelectric conversion layer). The position relationship between the photoelectric conversion site (A) and the photoelectric conversion site (B) on the substrate is not particularly limited.

  For example, on the substrate, the photoelectric conversion site (A) and the photoelectric conversion site (B) may be formed (directly formed) on the substrate without contacting each other, and the photoelectric conversion site (A) A photoelectric conversion part (B) may be laminated | stacked on top, and these may be combined. In the case of stacking, it may be stacked on at least a part of the photoelectric conversion site (A), the entire photoelectric conversion site (B) may be stacked on the photoelectric conversion site (A), and the substrate and the photoelectric conversion site (A). May be stacked on top of each other (i.e., spanning both of them), or a combination thereof. Note that the stacked portion has a mixed color hue of the first dye and the second dye. As described above, when there are a plurality of inks (b) (an ink set), a plurality of photoelectric conversion sites (B) can be formed. In such a case, the positional relationship between the respective photoelectric conversion sites (B) can be appropriately selected according to the design, similarly to the positional relationship between the photoelectric conversion sites (A) and the photoelectric conversion sites (B).

  In the present invention, usually, the photoelectric conversion site (A) is formed directly on the substrate. In particular, the photoelectric conversion site (A) and at least a part of the photoelectric conversion site (B) are often directly formed on the substrate.

  In addition, the coating order of the ink (a) and the ink (b) can be appropriately selected according to the design (or the positional relationship between the photoelectric conversion sites (A) and (B)). For example, when at least the photoelectric conversion site (A) is directly formed on the substrate, after coating the ink (a) on the substrate to form the photoelectric conversion site (A), (i) on the substrate The photoelectric conversion site (A) is not formed, and / or (ii) at least part of the photoelectric conversion site (A) is coated with ink (b) to form the photoelectric conversion site (B). Also good. In particular, in many cases, the ink (b) is coated at least on a portion where the photoelectric change portion (A) is not formed.

  The coating method is not particularly limited, and for example, air knife coating method, roll coating method, gravure coating method, blade coating method, doctor blade method, squeegee method, dip coating method, spray method, spin coating method, inkjet printing method Etc. can be exemplified. After application, it may be dried at a predetermined temperature (for example, room temperature to about 150 ° C.).

  In the present invention, the composition (a) and the composition (b) are applied on the substrate, and then the semiconductor is heated (or heated at a high temperature (eg, 500 ° C. or higher) without sintering (or firing) the semiconductor. Without] a photoelectric conversion layer is formed. In the present invention, a photoelectric conversion layer having sufficient photoelectric conversion characteristics (further, durability and adhesion to a substrate) can be formed without going through such a sintering step.

  As described above, the photoelectric conversion layer is formed on the substrate (conductive substrate), and a laminate is obtained. The thickness of the photoelectric conversion layer (total thickness when the photoelectric conversion sites (A) and (B) are laminated) is, for example, 0.1 to 100 μm (for example, 0.3 to 70 μm), preferably 0.5 to It may be about 50 μm (for example, 1 to 30), more preferably about 3 to 20 μm.

  The laminate obtained as described above has a conductor layer and a photoelectric conversion layer, and can be used as an electrode constituting the photoelectric conversion element. Hereinafter, the photoelectric conversion element will be described in detail.

[Photoelectric conversion element]
The photoelectric conversion element includes the laminate (electrode). That is, the photoelectric conversion element includes a laminate as an electrode. A solar cell is mentioned as an example of a typical photoelectric conversion element. In particular, when the photoelectric conversion layer contains a dye, the photoelectric conversion element forms a dye-sensitized solar cell.

  A solar cell includes, for example, a laminate as an electrode, a counter electrode disposed to face the electrode (photoelectric conversion layer side of the electrode), and an electrolyte layer interposed between these electrodes and sealed. It is configured. That is, the electrolyte layer (or electrolyte) is composed of both electrodes (or edges thereof) made of a sealing material [for example, a thermoplastic resin (such as an ionomer resin) or a thermosetting resin (such as an epoxy resin or a silicone resin). It is interposed (or encapsulated) in the space or gap formed by the sealing process.

  Note that the counter electrode is a positive electrode or a negative electrode depending on the type of semiconductor constituting the electrode (or laminate). That is, when the semiconductor is an n-type semiconductor, the counter electrode forms a positive electrode (a stacked body is a negative electrode), and when the semiconductor is a p-type semiconductor, the counter electrode forms a negative electrode (a stacked body is a positive electrode).

  The counter electrode is composed of a conductive substrate and a catalyst layer (positive electrode catalyst layer or negative electrode catalyst layer) formed on the conductive substrate (or on the conductive layer of the conductive substrate) in the same manner as the laminate. The In addition, when a conductor layer has a reducing ability in addition to conductivity, it is not always necessary to provide a catalyst layer. In addition, a counter electrode makes the surface of a conductor layer or a catalyst layer oppose a laminated body (or electrode). In the counter electrode, the conductive substrate may be a substrate in which a layer having both a conductive layer and a catalyst layer (conductive catalyst layer) is formed on a base substrate as described later, in addition to the same substrate as described above. . The catalyst layer (positive electrode catalyst layer or negative electrode catalyst layer) is not particularly limited, and can be formed of a conductive metal (such as gold or platinum), carbon, or the like.

  The catalyst layer (positive electrode catalyst layer or negative electrode catalyst layer) may be a non-porous layer (or non-porous layer) or a layer having a porous structure (porous layer). Such a porous layer (porous catalyst layer) may be composed of a porous catalyst component (porous catalyst component), and a porous component (porous component) and a catalyst supported on the porous component. You may comprise with a component and you may comprise combining these. That is, the porous catalyst component is a component that has porosity and functions as a catalyst component (a component having both porosity and catalyst function). In the latter embodiment, the porous component may have a catalytic function.

  Examples of the porous catalyst component include metal fine particles (for example, platinum black), porous carbon [carbon black (carbon black aggregate) such as activated carbon, graphite, ketjen black, furnace black, acetylene black, carbon nanotube ( Carbon nanotube aggregate)) and the like. These components may be used alone or in combination of two or more. Among the porous catalyst components, activated carbon or the like can be suitably used.

  Examples of the porous component include metal compound particles [for example, particles (fine particles) of the above-described conductive metal oxide (for example, tin-doped indium oxide) and the like) in addition to the porous carbon. These components may be used alone or in combination of two or more. Examples of the catalyst component include a conductive metal (for example, platinum).

  The shape (or form) of the porous catalyst component and the porous component is not particularly limited, and may be particulate or fibrous, and is preferably particulate.

  The average particle diameter of such a particulate porous catalyst component and porous component (porous particle) is, for example, 1 to 1000 μm (for example, 5 to 700 μm), preferably 10 to 500 μm (for example, 20 to 400 μm). More preferably, it may be about 30 to 300 μm (for example, 40 to 200 μm), particularly about 50 to 150 μm (for example, 70 to 100 μm).

The specific surface area of the porous catalyst component and the porous component is, for example, 1 to 4000 m ² / g (for example, 10 to 3500 m ² / g), preferably 20 to 3000 m ² / g (for example, 30 to 2500 m ² / g). , more preferably 50~2000m ² / g (e.g., 100~1500m ² / g), particularly 200~1000m ² / g (e.g., 300~500m ² / g) may be about.

  The porous layer (porous catalyst layer) may contain a binder component [for example, a resin component [for example, a thermoplastic resin such as cellulose derivative (methylcellulose); a thermosetting resin such as an epoxy resin] or the like. May be included.

  The ratio of the binder component is, for example, 0.1 to 50% by weight, preferably 0.5 to 40% by weight, more preferably 1 to 30% by weight (for example, with respect to the entire porous layer (porous catalyst layer)). 3 to 20% by weight).

  The electrode having a porous layer only needs to have at least a porous layer, and is usually composed of at least a substrate (a substrate that may be a conductive substrate) and a porous catalyst layer. As an electrode having a typical porous layer, (i) a conductive substrate (a substrate in which a conductive layer is formed on a base substrate, the conductive substrate illustrated above), and the conductive substrate (or a conductive material) Layer) and an electrode (or laminate) composed of a porous catalyst layer composed of a porous catalyst component, (ii) a base substrate (such as the base substrate illustrated above), and the base substrate And an electrode (or laminate) formed with a porous catalyst layer formed of a porous component and a catalyst component (for example, a porous component on which the catalyst component is supported).

  The thickness of the porous layer (porous catalyst layer) is, for example, 0.1 to 100 μm (for example, 0.3 to 70 μm), preferably 0.5 to 50 μm (for example, 0.7 to 40 μm), and more preferably. It may be about 1 to 30 μm.

  The electrolyte layer may be formed of an electrolyte solution containing an electrolyte and a solvent, or may be formed of a solid layer (or gel) containing an electrolyte. The electrolyte constituting the electrolytic solution is not particularly limited, and is a general-purpose electrolyte, for example, a combination of a halogen (halogen molecule) and a halide salt [for example, a combination of bromine and a bromide salt, an iodine and an iodide salt Combinations, etc.]. Counter ions (cations) constituting the halide salt include metal ions [for example, alkali metal ions (for example, lithium ions, sodium ions, potassium ions, cesium ions, etc.), alkaline earth metal ions (for example, magnesium ions, Quaternary ammonium ion [tetraalkylammonium salt, pyridinium salt, imidazolium salt (eg, 1,2-dimethyl-3-propylimidazolium salt)] and the like. The electrolytes may be used alone or in combination of two or more.

  Among these, preferable electrolytes include combinations of iodine and iodide salts, particularly iodine and metal iodide salts [for example, alkali metal salts (lithium iodide, sodium iodide, potassium iodide, etc.), quaternary Combination with ammonium salt and the like].

  The solvent constituting the electrolytic solution is not particularly limited, and a general-purpose solvent can be used. For example, alcohols (for example, alkanols such as methanol, ethanol and butanol; glycols such as ethylene glycol, diethylene glycol and polyethylene glycol) ), Nitriles (acetonitrile, methoxyacetonitrile, propionitrile, 3-methoxypropionitrile, benzonitrile, etc.), carbonates (ethylene carbonate, propylene carbonate, diethyl carbonate, etc.), lactones (gamma-butyrolactone, etc.), Ethers (chain ethers such as 1,2-dimethoxyethane, dimethyl ether and diethyl ether; tetrahydrofuran, 2-methyltetrahydrofuran, dioxolane, 4-methyl Cyclic ethers), sulfolane such as oxolane (such as sulfolane), sulfoxides (dimethyl sulfoxide, etc.), amides (N, N-dimethylformamide, N, N- dimethylacetamide, etc.), water, and the like. The solvents may be used alone or in combination of two or more.

  In the photoelectric conversion element, the ionic polymer and the electrolytic solution are in contact (or the ionic polymer is present in the electrolytic solution). As described above, when the pH of the ionic polymer is adjusted, the photoelectric conversion element The pH of the ionic polymer may be adjusted to be in the same range as described above. From the viewpoint of such pH adjustment, a component that does not affect pH adjustment may be preferably used as the component constituting the electrolytic solution. For example, a neutral solvent or a non-acidic solvent (or an aprotic solvent) may be suitably used as the electrolytic solution.

  In the electrolytic solution, the concentration of the electrolyte may be, for example, about 0.01 to 10M, preferably about 0.03 to 8M, and more preferably about 0.05 to 5M. Further, when a halogen (iodine etc.) and a halide salt (iodide salt etc.) are combined, the ratio of these is halogen / halide salt (molar ratio) = 1 / 0.5 to 1/100, preferably 1. / 1 to 1/50, more preferably about 1/2 to 1/30.

  In addition to the electrolytes exemplified above, the electrolyte constituting the solid layer containing an electrolyte includes a solid electrolyte {eg, a resin component [eg, a thiophene polymer (eg, polythiophene)], a carbazole polymer (eg, Poly (N-vinylcarbazole), etc.], organic solid components such as low molecular organic components (eg, naphthalene, anthracene, phthalocyanine, etc .; inorganic solid components such as silver iodide, etc.). These components may be used alone or in combination of two or more.

  The solid layer is a solid layer in which the electrolyte or electrolytic solution is held on a gel substrate [eg, thermoplastic resin (polyethylene glycol, polymethyl methacrylate, etc.), thermosetting resin (epoxy resin, etc.), etc.] Also good.

  Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1
Titanium oxide particles (manufactured by Ishihara Sangyo Co., Ltd., “ST-01”, average primary particle diameter 7 nm, specific surface area 300 m ² / g, anatase type crystal) 10 parts by weight, anionic polymer (“Nafion 117” manufactured by Aldrich), 5 1-propanol / 2-propanol mixed solution containing at a ratio of% by weight, ion exchange capacity 0.9 meq / g, pH (25 ° C.) = 1, occupied area of about 0.024 nm ² per molecule) 25 parts by weight (ie And 1.25 parts by weight of anionic polymer) and 65 parts by weight of 2-propanol (manufactured by Tokyo Chemical Industry Co., Ltd.) were added, and the mixture was ultrasonically stirred for 1 hour to prepare a dispersion. To this dispersion, 0.2 part by weight of a dye (N719, manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight: 1188.57, occupied area of about 1 nm ² per molecule) was added, and the mixture was further ultrasonically stirred for 1 hour. Conversion ink 1 (red purple) was prepared.

  Further, photoelectric conversion ink 2 (blue) was prepared in the same manner except that the dye was changed to Basic Blue 12 (manufactured by Tokyo Chemical Industry Co., Ltd.) and the addition amount was 5 parts by weight.

  After the photoelectric conversion ink 1 is spray-coated on the ITO layer side of a glass substrate with ITO (Luminescence Technology, size 25 mm × 25 mm, ITO layer thickness 0.14 μm) through the mask 1 in FIG. Dry at 0C. Subsequently, the photoelectric conversion ink 2 was spray-coated through the mask 2 of FIG. 1 and then dried at 70 ° C. in the atmosphere to form a photoelectric conversion layer having the pattern shown in FIG. (The thickness of the photoelectric conversion layer after drying is 2 μm)

  A glass substrate with ITO (Luminescence Technology) comprising a platinum thin film (formed by sputtering method, thickness 3 nm) formed on the ITO layer side (dye adsorption side) of the electrode on which the photoelectric conversion layer is formed and the ITO layer side as a counter electrode Company size 25 mm x 25 mm, ITO layer thickness 0.14 μm, facing the ITO layer side (platinum thin film side) on the diagonal line with two 1 mm diameter holes as the electrolyte injection port at an interval of 50 μm Then, each substrate (or each electrode or each ITO layer) is sealed with a sealing material or a spacer (Mitsui / DuPont Polychemical, “High Milan”) so as to tie each other, and heat-treated at 120 ° C. for 1 hour. Then, it was thermally bonded. And after filling electrolyte solution in the space | gap (or the space sealed with the sealing material) formed between both board | substrates (or both electrodes or both ITO layers) through electrolyte solution injection port, electrolyte solution injection port is used. A dye-sensitized solar cell was prepared by covering with an epoxy resin (Naldibant AR-R30, manufactured by Nichiban Co., Ltd.). As the electrolytic solution, an acetonitrile solution containing 0.5M 1,2-dimethyl-3-propylimidazolium iodide, 0.1M lithium iodide and 0.05M iodine was used.

Then, the obtained dye-sensitized solar cell was evaluated under conditions of AM 1.5, 100 mW / cm ² and 25 ° C. using a solar simulator (“XES-301S + EL-100” manufactured by Mitsunaga Electric Co., Ltd.). . The output characteristics of the obtained solar cell are shown in FIG.

  Further, in the obtained solar cell, the output characteristics one week after the production were measured in the same manner, but there was no change in the output characteristics.

(Example 2)
In Example 1, it replaced with spray application and it carried out similarly to Example 1 except having formed the pattern of photoelectric conversion layers of the pattern shown in FIG. 2 using the inkjet apparatus (ID-225D by ULVAC, Inc.). A dye-sensitized solar cell was prepared and evaluated. The obtained output characteristics are shown in FIG.

  Further, in the obtained solar cell, the output characteristics one week after the production were measured in the same manner, but there was no change in the output characteristics.

(Example 3)
In Example 1, the amount of 2-propanol in the photoelectric conversion layer inks 1 and 2 is 10 parts by weight, and instead of spray coating, a screen printer (LS-150TV type screen printer manufactured by Neurong Seimitsu Kogyo Co., Ltd.) is used. A dye-sensitized solar cell was prepared and evaluated in the same manner as in Example 1 except that the photoelectric conversion layer having the pattern shown in FIG. 2 was formed. The obtained output characteristics are shown in FIG.

  Further, in the obtained solar cell, the output characteristics one week after the production were measured in the same manner, but there was no change in the output characteristics.

(Example 4)
In Example 1, it replaced with the glass substrate with ITO, and it carried out similarly to Example 1 except having set it as the polyethylene terephthalate (PET) film with ITO (The product made from Aldrich, size 30x50 mm, thickness of ITO layer 0.12 micrometer). A dye-sensitized solar cell was prepared and evaluated. The obtained output characteristics are shown in FIG.

  Further, in the obtained solar cell, the output characteristics after one week after production were measured in the same manner, but there was no change in the output characteristics.

(Example 5)
First, in Example 1, a photoelectric conversion ink 3 (pink) was prepared in the same manner except that the dye was changed to sulforhodamine B (manufactured by Tokyo Chemical Industry Co., Ltd.) and the addition amount was 5 parts by weight. did. And the dye-sensitized solar cell was produced and evaluated like Example 2 except having formed the photoelectric converting layer of the pattern shown in FIG. The obtained output characteristics are shown in FIG.

  Moreover, the open circuit voltage before and after light irradiation (before and after light shielding) is shown in FIG. The light shielding after the light irradiation was performed by turning off the lamp of the solar simulator. As is apparent from FIG. 5, it was found that the device had photoelectric conversion characteristics and a power storage function.

  The ink set of the present invention is useful for forming a photoelectric conversion layer or a photoelectric conversion element (such as a dye-sensitized solar cell) having a plurality of hues. In particular, since the conventional coating method can be applied without sintering in the present invention, a photoelectric conversion having excellent design properties according to a desired design as well as a simple design. A layer or a photoelectric conversion element can be easily formed.

Claims (13)

  A laminated body composed of a conductive substrate and a photoelectric conversion layer stacked on the substrate and having a plurality of hues, wherein the photoelectric conversion layer includes an ink containing a semiconductor, an ionic polymer, and a first dye ( A laminate including the photoelectric conversion site (A) formed in a) and the photoelectric conversion site (B) formed of an ink (b) containing a semiconductor, an ionic polymer, and a second dye different from the first dye. body.   The laminate according to claim 1, wherein in the ink (a) and the ink (b), the semiconductor is at least one selected from titanium oxide nanoparticles, zinc oxide nanoparticles, and tin oxide nanoparticles.   The laminate according to claim 1 or 2, wherein in the ink (a) and the ink (b), the ionic polymer is composed of a fluorine-containing resin having a sulfo group.   The laminate according to any one of claims 1 to 3, wherein the ratio of the ionic polymer in the ink (a) and the ink (b) is 0.05 to 20 parts by weight with respect to 1 part by weight of the semiconductor.   In the ink (a) and the ink (b), the semiconductor is composed of titanium oxide nanoparticles, the ionic polymer is composed of a fluorine-containing resin having a sulfo group, and the proportion of the ionic polymer is 1 weight of the semiconductor. It is 0.05-8 weight part with respect to a part, The laminated body in any one of Claims 1-4.   The laminate according to any one of claims 1 to 5, wherein the photoelectric conversion site (A) and at least a part of the photoelectric conversion site (B) are directly formed on the conductive substrate.   The photoelectric conversion part (B) forms a plurality of photoelectric conversion parts having different hues by the ink (b) composed of a plurality of inks different in colorant, and the photoelectric conversion layer has three or more hues. The laminated body in any one of 6.   The laminate according to any one of claims 1 to 7, wherein the photoelectric conversion layer has a thickness of 0.1 to 100 µm.   An ink set for forming a photoelectric conversion layer having a plurality of hues, wherein the ink (a) includes a semiconductor, an ionic polymer, and a first dye, and is different from the semiconductor, the ionic polymer, and the first dye. And an ink set (b) containing two pigments.   An ink (a) containing a semiconductor, an ionic polymer and a first dye and an ink (b) containing a second dye different from the semiconductor, the ionic polymer and the first dye are coated on the conductive substrate. The method of forming the photoelectric conversion layer which has a photoelectric conversion site | part (A) and a photoelectric conversion site | part (B), without sintering a semiconductor, and manufacturing the laminated body in any one of Claims 1-8.   After the ink (a) is coated on the conductive substrate to form the photoelectric conversion site (A), at least a part of the ink (b) is not formed with the photoelectric conversion site (A) on the conductive substrate. The manufacturing method of Claim 10 which coats.   The photoelectric conversion element provided with the laminated body in any one of Claims 1-8.   It was comprised with the laminated body in any one of Claims 1-8 as an electrode, the counter electrode arrange | positioned facing this electrode, and the electrolyte layer which interposed between these electrodes and was sealed. The photoelectric conversion element according to claim 12, which is a dye-sensitized solar cell.