WO2010101057A1

WO2010101057A1 - Photoelectric conversion device and dye

Info

Publication number: WO2010101057A1
Application number: PCT/JP2010/052869
Authority: WO
Inventors: 浩司瀬川; 城太郎中崎; 聡内田; 久坂井
Original assignee: 京セラ株式会社
Priority date: 2009-03-06
Filing date: 2010-02-24
Publication date: 2010-09-10
Also published as: JPWO2010101057A1; JP5240740B2

Abstract

Disclosed is a photoelectric conversion device (X1) which comprises a first photoelectric conversion body that contains an electron transport material (14), a dye (13) that is positioned on top of the electron transport material (14) and contains a pentavalent phosphorus porphyrin represented by general formula 1, and a hole transport material (15) that is positioned on top of the dye (13).

Description

Photoelectric conversion device and dye

The present invention relates to a photoelectric conversion device and a dye that can be suitably used for the photoelectric conversion device.

A dye-sensitized solar cell, which is one of photoelectric conversion devices, does not require high-temperature processing or a vacuum device in the manufacturing process. For this reason, it is considered advantageous for cost reduction, and research and development have been promoted rapidly in recent years.

A general dye-sensitized solar cell includes a light working electrode and a conductive glass counter electrode. For example, the optical working electrode is provided with a porous titanium oxide layer obtained by sintering fine particles having a particle size of about 20 nm on a conductive glass substrate, and a single molecule of dye is formed on the particle surface of the porous titanium oxide layer. It is constituted by making it adsorb. In addition, the conductive glass counter electrode is configured, for example, by depositing platinum on the glass surface by sputtering. The space between the conductive glass counter electrode and the photoactive electrode is filled with an electrolyte solution having a charge transport function including an iodine / iodide redox pair, and the electrolyte solution is sealed to form a dye-sensitized solar cell. Is done.

For example, organic dyes are used as the dyes adsorbed on the light working electrode of such dye-sensitized solar cells. As the organic dye, one having a porphyrin skeleton has been proposed (see, for example, Patent Documents 1 and 2).

However, dye-sensitized solar cells are required to further improve the photoelectric conversion efficiency.

Japanese Patent Laid-Open No. 2006-100047 Japanese Patent No. 2917471

A photoelectric conversion device according to an embodiment of the present invention includes an electron transport material, a dye containing pentavalent phosphorus porphyrin represented by the following general formula 1 located on the electron transport material, and a positive electrode located on the dye. A first photoelectric conversion body having a hole transport material. (In the formula, R1 to R14 are optional substituents.)

The dye according to one embodiment of the present invention includes pentavalent phosphorus porphyrin represented by the above general formula 1, wherein at least one of R1 to R4 is a phenyl group having an electron donating substituent.

It is sectional drawing which shows the photoelectric conversion apparatus which concerns on the 1st Embodiment of this invention. It is sectional drawing which shows the photoelectric conversion apparatus which concerns on the 2nd Embodiment of this invention. It is a characteristic view which shows the absorption spectrum of the pigment | dye which concerns on the Example of this invention. It is an IPCE spectrum of the photoelectric conversion apparatus which concerns on the Example of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same members are denoted by the same reference numerals.

<< First Embodiment >>
FIG. 1 is a cross-sectional view showing a photoelectric conversion device according to the first embodiment of the present invention. The photoelectric conversion device X1 according to the first embodiment of the present invention includes a conductive substrate 11, a metal oxide 14, a dye 13, an electrolyte 15, a transparent electrode 16, and a translucent covering body 17. I have. In this configuration, the electron transport material is the metal oxide 14 and the hole transport material is the electrolyte 15. The dye 13 is attached to the metal oxide 14 and is disposed between the metal oxide 14 that is an electron transport material and the electrolyte 15 that is a hole transport material. The first photoelectric converter 12 is composed of the metal oxide 14, which is an electron transport material, the dye 13, and the electrolyte 15 which is a hole transport material. The electron transport material has a function of receiving electrons from the dye 13 and transporting the electrons to an external circuit. The hole transport material has a function of receiving holes from the dye 13 and transporting holes to the external circuit (or a function of injecting electrons from the external circuit into the dye 13).

Next, the photoelectric conversion action of the photoelectric conversion device X1 according to this embodiment will be described. In the photoelectric conversion device X1, when light is incident from the arrow L in FIG. 1, the dye 13 absorbs light, the dye 13 is excited, and the electrons are LUMO (Lowest Unoccupied Molecular Orbital: lowest sky) Excited to orbital level. Then, the electrons excited to the LUMO level move at high speed to the conduction band (conduction band) level of the metal oxide 14 such as titanium oxide. The electrons moved to the conduction band level of the metal oxide 14 efficiently move between the metal oxide particles and reach the conductive substrate 11. Next, the electrons that have reached the conductive substrate 11 move to the transparent electrode 16 via a load (not shown) that is electrically connected between the conductive substrate 11 and the transparent electrode 16. Next, the electrons that have moved to the first transparent electrode 16 reduce a part of the electrolyte 15 in a catalyst (not shown) formed on the transparent electrode 16. Examples of the material of the catalyst include noble metals such as platinum, palladium, iridium, osmium, ruthenium, and rhodium, carbon, and organic conductive materials such as polyethylenedioxythiophene (PEDOT). When the reduced electrolyte 15 diffuses to the vicinity of the dye 13, an oxidation reaction occurs on the dye and causes an electron transfer to the HOMO level of the dye. Photoelectric conversion occurs as the electrons circulate as described above.

Each member of the photoelectric conversion device X1 according to the present embodiment will be described in detail.

<Conductive substrate>
The conductive substrate 11 is a support for the first photoelectric converter 12 and has a function of taking out current from the first photoelectric converter 12. Examples of the conductive substrate 11 include a metal substrate, a substrate in which a conductive member is contained in a base material, or a substrate in which a conductive film 11b is formed on the upper surface of an insulating substrate 11a.

Examples of the material of the metal substrate include metals such as titanium, stainless steel, aluminum, silver, copper, and nickel, or alloys of these metals.

An insulating material is used as the base material used for the above-described substrate containing a conductive member in the base material. For example, organic resin materials such as PET (polyethylene terephthalate), PEN (polyethylene naphthalate), polyimide, and polycarbonate are used. Or inorganic materials such as blue plate glass, soda glass, borosilicate glass, and ceramics. Examples of the conductive member contained in such a base material include metal fine particles and fine lines made of the above-described metal substrate material, or carbon (carbon) fine particles and fine lines.

As the above-mentioned substrate in which the conductive film 11b is formed on the upper surface of the insulating substrate 11a, the conductive film 11b is formed on the insulating substrate 11a made of the same material as the base material described above by, for example, the CVD method. Is mentioned. Examples of the conductive film 11b include a metal thin film, a transparent conductive film, or a laminated conductive film in which an ITO layer is sandwiched between a pair of titanium layers. Examples of the metal thin film include titanium, stainless steel, aluminum, silver, copper, and nickel. Examples of the transparent conductive film include ITO (tin-doped indium oxide, FTO (fluorine-doped tin oxide), and zinc oxide doped with aluminum.

In addition, if the conductive substrate 11 has a characteristic of reflecting light incident on the photoelectric conversion device X1, light can be incident again on the first photoelectric conversion body 12 that contributes to photoelectric conversion. The photoelectric conversion efficiency can be increased. Examples of the conductive substrate 11 having such light reflection characteristics include a silver or aluminum metal substrate. In addition, the conductive substrate 11 having the conductive film 11b is preferably a laminated conductive film in which a silver layer is sandwiched between silver or a pair of titanium layers, and such a conductive film 11b can be formed by, for example, vacuum deposition or ion plating. It can be formed by a method, a sputtering method, an electrolytic deposition method, or the like.

The thickness of the conductive substrate 11 is 0.01 mm to 5 mm, preferably 0.02 mm to 3 mm. The thickness of the conductive film 11b is 0.001 μm to 10 μm, preferably 0.05 μm to 2 μm.

On the other hand, when the conductive substrate 11 is made of a light-transmitting material, light that enters from a direction opposite to the direction indicated by the arrow L in FIG. 1 can also enter, and the photoelectric conversion device X1. The light receiving area can be expanded. On the other hand, when the conductive substrate 11 is made of a light-transmitting material, aluminum, silver or the like having high light reflection characteristics is applied to the back surface of the conductive substrate 11 (the lower surface of the conductive substrate in FIG. 1). When the light reflection property is increased by forming a film, light can be re-incident on the first photoelectric conversion body 12 that contributes to photoelectric conversion, so that the photoelectric conversion efficiency can be increased.

Further, if concavities and convexities in the wavelength order of light incident on the upper surface (surface on which the first photoelectric conversion body 12 is disposed) on which light of the conductive substrate 11 is incident are provided, a light confinement effect is provided. Therefore, the photoelectric conversion efficiency can be increased.

<Electron transport material>
The electron transport material has a function of transporting charges (electrons) from the dye, and a conductor, a semiconductor, an electrolyte, or the like is used. In the present embodiment, the metal oxide 14 made of a semiconductor material functions as an electron transport material.

The dye 13 is attached to the porous surface of the metal oxide 14 made of a semiconductor material. And the pigment | dye 13 absorbs light and moves the excited electron to the metal oxide 14, and photoelectric conversion is performed efficiently. The thickness of the metal oxide 14 is preferably 0.1 μm to 50 μm, for example. Further, the thickness of the metal oxide 14 is more preferably 1 μm to 20 μm from the viewpoint of increasing the photoelectric conversion efficiency without excessively reducing the light transmittance.

The metal oxide 14 includes titanium oxide (TiO ₂ ) that is an oxide of titanium (Ti), tin oxide (SnO ₂ ) that is an oxide of tin (Sn), or zinc oxide (ZnO) that is an oxide of zinc. It consists of an n-type semiconductor. An oxide having such semiconductor properties has a conduction band lower than the LUMO energy level of the dye 13 described later in detail, and has relatively few lattice defects, so that electrons are not easily trapped in the defects. Therefore, the photoelectric conversion efficiency of the photoelectric conversion device X1 can be increased. In particular, titanium oxide (TiO ₂ ) is most preferable from the viewpoint of having fewer lattice defects than other metal oxides (SnO ₂ , ZnO).

The metal oxide 14 is preferably composed of a porous material from the viewpoint of increasing the surface area to which the dye 13 is attached and attaching more dye. Such a porous body has a porosity of 20% to 80%, more preferably 40% to 60%. Further, the metal oxide 14 is formed of, for example, fine particles or an aggregate of fine linear bodies such as needle-like bodies, tubular bodies, or columnar bodies, and has an average particle diameter or average wire diameter of 5 nm to The thickness is preferably 500 nm, and more preferably 10 nm to 200 nm from the viewpoint of increasing the bonding area between the fine particles or the linear bodies and simplifying the material production. Furthermore, if the metal oxide 14 is formed of such a porous body, the surface becomes uneven, so that the light confinement effect can be enhanced.

Next, an example of a method for forming the metal oxide 14 will be described. Hereinafter, the metal oxide 14 formed of titanium oxide will be described. First, acetylacetone is added to an anatase powder of titanium oxide, and then kneaded with deionized water to prepare a titanium oxide paste stabilized with a surfactant. Next, this paste is applied onto the conductive substrate 11 by, for example, a doctor blade method, and is heat-treated in the atmosphere at a temperature of 300 ° C. to 600 ° C. for 10 minutes to 60 minutes, whereby the metal oxide 14 Can be formed.

When the conductive substrate 11 is made of a material having low heat resistance, such as an organic resin material, the metal oxide 14 is formed at a relatively low temperature such as an electrodeposition method, an electrophoretic electrodeposition method, or a hydrothermal synthesis method. A possible method is preferably used, and in addition, microwave treatment, CVD / UV treatment, or the like may be performed as post-processing.

<Dye>
The dye 13 absorbs light incident on the photoelectric conversion device X1, and the electron located in the HOMO of the dye is excited to the position of the LUMO of the dye and moves the electron to the metal oxide 14 from the LUMO. Have.

The dye 13 contains pentavalent phosphorus porphyrin represented by the following general formula 1.

In the general formula 1, R1 to R14 are arbitrary substituents. The pentavalent phosphoporphyrin represented by the general formula 1 has a stronger cationic property than porphyrins having the same shape and different central metals, and therefore the HOMO-LUMO energy level gap is narrowed, and even in a longer wavelength region. Shows light absorption. As a result, by using the pentavalent phosphorus porphyrin represented by the general formula 1, the long wavelength sensitivity of the photoelectric conversion device can be increased. Moreover, the cost reduction of material is implement | achieved by not containing a noble metal.

In the general formula 1, at least one of R1 to R4 is preferably a phenyl group having an electron-donating substituent. In this case, there is a contribution of charge transfer transition from these substituents to the center of the phosphorus porphyrin. Therefore, compared to a conventional dye having a porphyrin derivative having an absorption wavelength region of 400 to 700 nm, light in a longer wavelength region can be absorbed, and the photoelectric conversion efficiency of the photoelectric conversion device X1 can be improved. it can.

In particular, the phenyl group having such an electron-donating substituent is preferably a (dialkylamino) phenyl group, an aminophenyl group, or a hydroxyphenyl group. In this case, light absorption in which the absorption wavelength range is expanded to 800 nm or more is shown, and the photoelectric conversion efficiency of the photoelectric conversion device X1 can be further increased.

In addition, since the general formula 1 is a cation, the dye 13 has an arbitrary anion such as a chloride ion or an iodide ion as a counter ion.

Next, the photoelectric conversion effect | action by the combination of the pigment | dye 13, the metal oxide 14, and the electrolyte 15 is demonstrated. The dye 13 is represented by the general formula 1 in which R1 = R2 = R3 = R4 = para (dimethylamino) phenyl group, R5 = R6 = carboxyphenyloxy group, R7 = R8 = R9 = R10 = R11 = R12 = R13 = The description will be made with R14 = H. The dye 13 that has absorbed the light excites electrons from the HOMO level (−5.59 eV) to the LUMO level (−4.11 eV). The conduction band of the metal oxide 14 is −4.2 eV for TiO ₂ , −4.4 eV for ZnO, and −4.8 eV for SnO ₂ . Thus, the LUMO level of the dye 13 has an energy level higher than that of the above-described conduction band of the metal oxide 14, so that the electrons of the LUMO level easily move to the conduction band of the metal oxide 14. . In addition, if the HOMO level (−5.59 eV) of the dye 13 is lower than the oxidation-reduction potential of the electrolyte 15, electrons easily move from the electrolyte 15 to the HOMO level of the dye 13. The redox potential of the electrolyte 15 is, for example, −5.1 eV in the case of iodine redox obtained by dissolving tetrapropylammonium iodide, lithium iodide, and iodine in methoxypropionitrile.

The substituents R1 to R14 in the general formula 1 are hydrogen, halogen, di-tert-butylphenyl group, alkyl group, phenyl group, carboxyl group, carboxyphenyl group, carbomethoxyphenyl group, styrylcarboxyl group, thiocyanate group, cyano group. , Cyanoacrylate group, sulfonic acid group, sulfonyl group, hydroxamic acid group, hydroxyl group, nitro group, amino group, mercapto group, aryl group, alkoxyl group, aryloxy group, alkylthio group, arylthio group, alkylamino group, arylamino group , Sulfonic acid ester group, sulfonic acid amide group, carboxylic acid ester group, carboxylic acid amide group, carbonyl group, silyl group, siloxy group, tertiary butyl group, phosphoryl group and the like.

In addition, it is preferable that at least one of the substituents R1 to R4 exhibits a strong electron donating property so that the dye 13 exhibits absorption at a long wavelength due to the contribution of the charge transfer transition. Examples of such electron donating substituents include (dialkylamino) phenyl groups such as (dimethylamino) phenyl group and (diethylamino) phenyl group, aminophenyl group, and hydroxyphenyl group.

In addition, it is preferable that at least one of the substituents R1 to R14 is a highly adhesive substituent so that the dye 13 is efficiently attached to the metal oxide 14. Examples of such a highly adhesive substituent include a carboxyl group, a carboxyphenyl group, a sulfo group, a sulfophenyl group, a hydroxyl group, an alkoxyl group, an aryl group, and a phosphoryl group. In addition, the highly adhesive substituent is preferably a carboxyphenyl group from the viewpoint of efficient electron transfer from the dye 13 to the metal oxide 14.

In particular, at least one of R5 and R6 in the general formula 1 preferably has a carboxyl group. In this case, since the distance between the resonance site of the porphyrin ring and the metal oxide 14 can be further shortened, the electron transfer from the dye 13 to the metal oxide 14 can be further increased.

Next, an example of a method for synthesizing the dye 13 represented by the general formula 1 will be described. Para (dimethylamino) benzaldehyde and pyrrole were added to a solvent in which propionic acid and octanoic acid were mixed at a ratio of 1: 1 and heated for 2 hours. After cooling, the precipitate formed was washed with tetrakis [para (dimethylamino ) Phenyl] porphyrin. This tetrakis [para (dimethylamino) phenyl] porphyrin and phosphorus trichloride are dispersed in dry pyridine, and after heating, the liquid is distilled off under reduced pressure and separated and purified by column chromatography to obtain a pentavalent phosphoporphyrin dichloroate. . The pentavalent phosphoporphyrin dichloroate is mixed with parahydroxybenzoic acid and dry pyridine, heated, and separated and purified by column chromatography to obtain R1 = R2 = R3 = R4 = para (dimethylamino) in the general formula 1. A dye 13 having a phenyl group, R5 = R6 = carboxyphenyloxy group, R7 = R8 = R9 = R10 = R11 = R12 = R13 = R14 = H can be obtained.

Next, a method for attaching the dye 13 to the metal oxide 14 will be described. As a method for attaching the dye 13, for example, a method in which the conductive substrate 11 on which the metal oxide 14 is formed is immersed in a solution in which the dye 13 is dissolved, or the conductive substrate 11 on which the metal oxide 14 is formed is used as a sealing agent. After the periphery is sealed by, for example, a method in which a solution in which the dye 13 is dissolved is injected from an injection port of the sealing agent, and the solution is circulated in the sealed interior to attach the dye 13 to the metal oxide 14. It is done. Further, when the former is immersed in a solution in which the dye 13 is dissolved, the temperature of the solution and the atmosphere is not particularly limited. For example, the atmosphere may be at atmospheric pressure, and the temperature may be room temperature. Can be appropriately adjusted depending on the type of the dye 13, the type of the solvent, the concentration of the solution, the temperature, and the like. The solvent used to dissolve the dye 13 is 1 aromatic hydrocarbon such as toluene, alcohols such as ethanol, ketones such as acetone, ethers such as diethyl ether and tetrahydrofuran, nitrogen compounds such as acetonitrile, and the like. The seed | species or what mixed 2 or more types is mentioned. At this time, the concentration of the dye 13 in the solution is preferably about 5 × 10 ⁻⁵ to 1 × 10 ⁻³ mol / l. Further, this solution may contain, as an additive, tertiary butyl pyridine, which is a weakly basic compound, or deoxycholic acid, which is a weakly acidic compound, in order to suppress aggregation of the dye 13.

<Hole transport material>
The hole transport material has a function of transporting charges (holes) from the dye, and a conductor, a semiconductor, an electrolyte, or the like is used. In the present embodiment, the electrolyte 15 functions as a hole transport material. Examples of the electrolyte 15 include a liquid electrolyte, a solid electrolyte, a gel electrolyte, and a molten salt.

As the liquid electrolyte, for example, a quaternary ammonium salt, a Li salt or the like dissolved in a solvent such as propylene carbonate or acetonitrile can be used. Further, tetrapropylammonium iodide, lithium iodide, or iodine dissolved in a solvent such as methoxypropionitrile can be used.

Examples of solid electrolytes include those having a sulfonimidazolium salt, a tetracyanoquinodimethane salt, a dicyanoquinodiimine salt, etc. in a polymer chain such as polyethylene oxide, polyethyleneimine or polyethylene.

Gel electrolytes are roughly classified into chemical gels and physical gels. A chemical gel is a gel formed by a chemical bond by a cross-linking reaction or the like, and a physical gel is gelled near room temperature due to a physical interaction. The gel electrolyte is a gel obtained by mixing a host polymer such as polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polyvinyl alcohol, polyacrylic acid or polyacrylamide with acetonitrile, ethylene carbonate, propylene carbonate or a mixture thereof. An electrolyte is preferred. When using a gel electrolyte or solid electrolyte, a low-viscosity precursor is contained in the nanoparticles, and a two-dimensional or three-dimensional crosslinking reaction is caused by means such as heating, ultraviolet irradiation, or electron beam irradiation. Can be gelled or solidified.

As the molten salt, for example, a molten salt of iodide can be used. Examples of the molten salt of iodide include iodides such as imidazolium salt, quaternary ammonium salt, isoxazolidinium salt, isothiazolidinium salt, pyrazolidium salt, pyrrolidinium salt, pyridinium salt and the like. Specific examples of the above-mentioned molten salt of iodide include, for example, 1,1-dimethylimidazolium iodide, 1-methyl-3-ethylimidazolium iodide, 1-methyl-3-pentylimidazolium iodide. 1-methyl-3-isopentylimidazolium iodide, 1-methyl-3-hexylimidazolium iodide, 1-methyl-3-ethylimidazolium iodide, 1,2-dimethyl-3-propylimidazole iodide 1-ethyl-3-isopropylimidazolium iodide, pyrrolidinium iodide and the like.

Examples of the conductor or semiconductor used as the hole transport material include a compound semiconductor containing monovalent copper, GaP, NiO, CoO, FeO, Bi ₂ O ₃ , MoO ₂ , Cr ₂ O _{3 and the} like. In particular, a semiconductor containing monovalent copper is preferable. Examples of the compound semiconductor containing monovalent copper include CuI, CuInSe ₂ , Cu ₂ O, CuSCN, CuS, CuInS ₂ , and CuAlSe ₂ , and CuI is preferable from the viewpoint of easy manufacture.

<Transparent electrode>
The transparent electrode 16 has conductivity capable of exchanging charges with the electrolyte 15 and also has translucency capable of transmitting light contributing to photoelectric conversion. Examples of the transparent electrode 16 include a tin-doped indium oxide (ITO) film, an impurity-doped indium oxide (In ₂ O ₃ ) film, an impurity-doped zinc oxide (ZnO) film, a fluorine-doped tin dioxide film, and the like. And a laminated film formed by laminating the layers. The film forming method of the transparent electrode 16 described above can be variously selected according to the material to be formed, for example, a low temperature growth sputtering method, a low temperature spray pyrolysis method, a thermal CVD method, a solution growth method, a vacuum evaporation method. , Ion plating method, dip coating method, sol-gel method and the like. The transparent electrode 16 can have a light confinement effect by forming irregularities in the wavelength order of incident light on the surface thereof. Further, the transparent electrode 16 may be a thin metal film such as Au, Pd, or Al formed by a vacuum deposition method, a sputtering method, or the like. In order to efficiently exchange charges with the electrolyte 15, a catalyst (not shown) is formed on the transparent electrode 16. Examples of the material of the catalyst include noble metals such as platinum, palladium, iridium, osmium, ruthenium, and rhodium, carbon, and organic conductive materials such as polyethylenedioxythiophene (PEDOT).

<Translucent covering>
The translucent covering 17 has a translucency through which light contributing to photoelectric conversion can be transmitted, and has a function of protecting the transparent electrode 16 and the like from the outside. Examples of such a translucent covering 17 include a fluororesin, a polyester resin, a silicon polyester resin, a polyvinyl chloride resin, a PET (polyethylene terephthalate), PEN (polyethylene naphthalate), a resin sheet such as polyimide and polycarbonate, and a white plate. Examples thereof include inorganic sheets such as glass, soda glass, borosilicate glass and ceramics, or hybrid sheets formed by combining organic and inorganic materials. The thickness of the translucent covering 17 is 0.1 μm to 6 mm, preferably 1 μm to 4 mm.

Note that the photoelectric conversion device X1 may use a plurality of types of dyes 13 having different wavelengths of light to be absorbed. With such a form, it becomes possible to photoelectrically convert light in a wider wavelength region, and the photoelectric conversion efficiency is improved. Moreover, even if the plurality of photoelectric conversion devices X1 are stacked and the dye 13 used in each photoelectric conversion device X1 has a relationship in which the photoelectric conversion devices X1 have different absorption characteristics, a wider range It becomes possible to photoelectrically convert light in a wide wavelength region, and the photoelectric conversion efficiency is improved.

Such a photoelectric conversion device X1 can be a photovoltaic device by using the photoelectric conversion device X1 as a power generation means and supplying the generated power from the power generation means to a load. This photovoltaic power generation device uses, for example, one or more photoelectric conversion devices X1 connected in series (in series, parallel, or series-parallel if there are a plurality) as power generation means, and the generated power directly from this power generation means to a DC load. It has a mechanism which supplies. In addition, the photovoltaic power generation device converts the direct current power output from the photoelectric conversion device X1 into appropriate alternating current power through power conversion means such as an inverter, and then converts this generated power to a commercial power supply system or various electric devices. You may have the mechanism supplied to alternating current load. Furthermore, such a photovoltaic power generation device can be used as a photovoltaic power generation system of various modes by being installed in a building with good sunlight.

<< Second Embodiment >>
FIG. 2 is a sectional view showing a photoelectric conversion device according to the second embodiment of the present invention. The photoelectric conversion device X2 according to the second embodiment of the present invention has a second photoelectric conversion body 18 having a semiconductor layer on the electrolyte 15 side of the first photoelectric conversion body 12 in that the first photoelectric conversion apparatus X2 has the first photoelectric conversion body X2 of the present invention. This is different from the photoelectric conversion device X1 according to the embodiment. The second photoelectric converter 18 is arranged in a state of being interposed between the transparent electrode 16 and the intermediate layer 19. In the second embodiment of FIG. 2, the same components as those of the first embodiment of FIG.

The second photoelectric conversion body 18 has a photoelectric conversion function of converting incident light after absorbing incident light, and in particular, the light photoelectrically converted by the first photoelectric conversion body 12 What is excellent in the photoelectric conversion effect | action in the light of a different wavelength is preferable. Examples of the semiconductor layer of the second photoelectric conversion body 18 include a silicon-based thin film semiconductor layer, a compound semiconductor system such as CIGS (CuInGaSe), and an organic thin film semiconductor film. As the silicon system, for example, an amorphous silicon system, an amorphous silicon system including a nanosize crystal, a microcrystalline silicon system, and the like are preferable, and an amorphous silicon system is preferable from the viewpoint of having a short wavelength sensitivity and a small light deterioration. . The amorphous silicon system includes alloy systems such as amorphous silicon carbide and amorphous silicon nitride. Further, when these thin film semiconductor layers are composed of a plurality of layers, the junction layer may generate an internal electric field such as a pin junction type, a pn junction type, a Schottky junction type, or a hetero junction type. Good.

The intermediate layer 19 has a function of electrically connecting the first photoelectric converter 12 and the second photoelectric converter 18 and is made of a translucent conductive material. The material of the intermediate layer 19 may include at least one of a metal, a conductive oxide, and a conductive polymer.

In the case where the intermediate layer 19 is made of metal, it is preferable that the intermediate layer 19 is made of an island-shaped portion made of a large number of metals in order to improve translucency. The metal material is made of a platinum group element such as platinum or palladium, or a metal such as silver, aluminum, titanium, iron, copper, indium, chromium, or iridium.

When the intermediate layer 19 is a conductive oxide, the materials thereof are tin-doped indium oxide, fluorine-doped tin oxide, antimony-doped tin oxide, aluminum-doped zinc oxide, gallium-doped zinc oxide, zinc oxide, indium oxide, tin oxide, oxidation An oxide that can function as a transparent electrode, such as titanium or niobium-doped titanium oxide, is preferable.

When the intermediate layer 19 is a conductive polymer, the material is preferably polyethylene dioxythiophene (PEDOT) (may be doped with polystyrene sulfonate or toluene sulfonate), polyvinyl carbazole, thiophene, or the like.

Next, the amorphous silicon-based thin film semiconductor layer will be described in detail. As the thin film semiconductor layer, for example, a pin junction hydrogenated amorphous silicon based semiconductor film continuously deposited by plasma CVD is suitable. The semiconductor film may be a pin junction in which a p-type semiconductor film is provided on the transparent electrode 16 side, but may be a reverse junction nip junction. Note that the one-conductivity-type silicon-based semiconductor layer and the reverse-conductivity-type silicon-based semiconductor layer mean a layer composed of a p-type semiconductor and an n-type semiconductor, or an n-type semiconductor and a p-type semiconductor, respectively. Further, a silicon semiconductor layer that is substantially intrinsic means an i-type semiconductor. Here, if the i-type semiconductor film is amorphous (amorphous), at least one of the p-type semiconductor film and the n-type semiconductor film has microcrystals, or hydrogenated amorphous silicon (a-Si: H) An alloy film may be used. In addition, it is more preferable for the thin-film semiconductor layer to use hydrogenated amorphous silicon carbide for the p-type semiconductor film on the light incident side, because it increases translucency and reduces light penetration loss. Further, the thin film semiconductor layer may be formed using a catalytic CVD method as a film forming method other than the plasma CVD method. In addition, when the plasma CVD method and the catalytic CVD method are combined, light deterioration in the formed semiconductor film can be suppressed, so that reliability can be improved.

Next, an example of the manufacturing method of the 2nd photoelectric conversion body 18 is demonstrated. The p-type hydrogenated amorphous silicon (a-Si: H) film uses SiH ₄ + H ₂ gas and B ₂ H ₆ (diluted to 500 ppm with H ₂ ) gas as source gases, and the flow rates of these gases are Each film is optimized. This film thickness is preferably in the range of 50 to 200 mm from the viewpoint of reducing light loss while forming a sufficient internal electric field. The i-type hydrogenated amorphous silicon (a-Si: H) film is formed by using SiH ₄ + H ₂ gas as a source gas and optimizing the flow rate of these gases. This film thickness is preferably 500 to 5000 mm (0.05 μm to 0.5 μm) from the viewpoints of obtaining a sufficient photocurrent and transmitting light that contributes to power generation of the first photoelectric converter 12. Subsequently, the n-type hydrogenated amorphous silicon (a-Si: H) film uses SiH ₄ + H ₂ gas and PH ₃ (diluted to 1000 ppm with H ₂ ) gas as source gases, and the flow rates of these gases Each of these is optimized to form a film. This film thickness is preferably in the range of 50 to 200 mm from the viewpoint of reducing light loss while forming a sufficient internal electric field. The temperature of the translucent covering 17 and the transparent electrode 16 during film formation is preferably in the range of 150 ° C. to 300 ° C. for any of the p-type, i-type, and n-type films. In addition, the second photoelectric conversion body 18 including such a thin film semiconductor layer easily absorbs light having a wavelength of 300 nm to 700 nm, and has a wavelength range of 700 nm to 1100 nm that is easily absorbed by the dye 13. Photoelectric conversion is performed with light on the short wavelength side.

As described above, the photoelectric conversion device X <b> 2 has a structure in which the second photoelectric conversion body 18 is disposed on the light incident side, and the first photoelectric conversion body 12 is provided below the second photoelectric conversion body 18. Therefore, after the light in the wavelength region on the short wavelength side described above is absorbed by the second photoelectric converter 18, the light in the wavelength region on the long wavelength side that transmits the second photoelectric converter 18 is first The photoelectric conversion body 12 absorbs. Therefore, the photoelectric conversion device X2 can perform photoelectric conversion in a wider wavelength range, and thus can improve the photoelectric conversion efficiency. In addition, in the photoelectric conversion device X2, since the second photoelectric conversion body 18 that absorbs light having a wavelength close to ultraviolet light is disposed on the light incident side, deterioration of the dye 13 due to ultraviolet light can be reduced. .

Note that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention. For example, in the present embodiment, the materials shown as the electron transport material and the hole transport material are only shown as materials that transport electrons and holes as an example of the charge transport material, respectively, and each transports opposite charges. It doesn't matter. Further, when the conductive substrate 11 is transparent, light may be incident from the conductive substrate 11. Moreover, in the photoelectric conversion device X2 according to the second embodiment, an example in which the second photoelectric conversion body 18 is provided on the electrolyte 15 of the first photoelectric conversion body 12, that is, the dye 13 in the hole transport material. Although the example which laminated | stacked the 2nd photoelectric conversion body 18 in the position on the opposite side was shown, you may laminate | stack the 2nd photoelectric conversion body 18 in the position on the opposite side to the pigment | dye 13 in an electron transport material. Moreover, the photoelectric conversion device of the present invention is not limited to a so-called dye-sensitized solar cell, and can also be applied as a so-called organic thin film solar cell. In addition, as shown in the present embodiment, the dye of the present invention is suitable for application to a photoelectric conversion device, but is not limited thereto, and its broadband light absorption and acid / base response (charge transfer). The complex can be applied to a light shielding material, an indicator, and the like.

Hereinafter, examples of the present invention will be described.

(Preparation of pigment)
Para (dimethylamino) benzaldehyde and pyrrole were added to a solvent in which propionic acid and octanoic acid were mixed at a ratio of 1: 1 and heated for 2 hours. After cooling, the precipitate formed was washed with tetrakis [para (dimethylamino ) Phenyl] porphyrin was obtained. This tetrakis [para (dimethylamino) phenyl] porphyrin and phosphorus trichloride are dispersed in dry pyridine, and after heating, the liquid is distilled off under reduced pressure and separated and purified by column chromatography to obtain a pentavalent phosphoporphyrin dichloroate. It was. The pentavalent phosphoporphyrin dichloro product was mixed and heated with parahydroxybenzoic acid and dry pyridine, and then separated and purified by column chromatography to prepare the dye 13 represented by the general formula 1. In this example, in the general formula 1, R1 = R2 = R3 = R4 = para (dimethylamino) phenyl group, R5 = R6 = carboxyphenyloxy group, R7 = R8 = R9 = R10 = R11 = R12 = It has a structure of R13 = R14 = H. The counter ion is a chloride ion. The absorption spectrum of the resulting dye solution is shown in FIG.

(Production of metal oxide)
First, as the conductive substrate 11, a glass substrate with a fluorine-doped tin oxide film having a surface resistance value of 10Ω / □ (square) and a size of 15 mm × 25 mm was prepared. Next, a porous titanium oxide film that is the metal oxide 14 was formed on the conductive substrate 11. A porous titanium oxide film was manufactured by applying a titania paste Ti-Nanoxide T / SP made by SOLARONIXS on a conductive substrate 11 by a screen printing method using a screen of 4 mm × 4 mm size and 300 mesh, and 120 ° C. The operation of drying for 3 minutes was repeated 10 times, and then the conductive substrate 11 was baked at 500 ° C. for 30 minutes to form a porous titanium oxide film. The film thickness of the porous titanium oxide film was 18 μm as measured with a stylus type film thickness meter.

Next, the dye 13 synthesized as described above was dissolved in methanol to prepare 0.3 mM. Next, after immersing the conductive substrate 11 on which the porous titanium oxide film is formed in the solution containing the dye 13 at 50 ° C. for 60 minutes, the conductive substrate 11 is washed with methanol at room temperature, whereby the dye is obtained. A metal oxide 14 having 13 attached thereto was produced.

(Production of photoelectric conversion cell)
First, a transparent electrode 16 was produced in which platinum having a film thickness of about 1 nm was formed on a glass substrate with a fluorine-doped tin oxide film having two electrolyte solution injection holes having a diameter of about 0.7 mm. Next, an ionomer resin having a thickness of about 30 μm was pasted around the counter electrode 16, and the metal oxide 14 having the dye 13 attached thereto was adhered to the transparent electrode 16 through the ionomer resin. This ionomer resin seals a region sandwiched between the metal oxide 14 and the transparent electrode 16 from the outside. Next, an electrolyte solution prepared by dissolving 2.0 M lithium iodide and 0.025 M iodine in benzonitrile as an electrolyte is prepared, and the electrolyte solution is injected into the inside through the electrolyte solution injection hole. A conversion cell was produced.

(Characteristic evaluation of photoelectric conversion cell)
The produced photoelectric conversion cell was irradiated with a pseudo solar light source (AM1.5, 100 mW / cm ² ) using a solar simulator YSS-80 manufactured by Yamashita Denso Co., Ltd., and the current-voltage characteristics of the photoelectric conversion cell were measured. Moreover, the result of spectral sensitivity characteristic evaluation computed from the electric current value measured with Keithley Picoammeter using the hyper monolite SM250E system by a spectrometer company was shown in FIG.

From the results shown in FIG. 4, the photoelectric conversion cell of the example showed a spectral sensitivity that spreads over a wide wavelength region, particularly 1000 nm or more.

X1, X2: photoelectric conversion device 11: conductive substrate 11a: insulating substrate 11b: conductive film 12: first photoelectric conversion body 13: dye 14: metal oxide (electron transport material)
15: Electrolyte (hole transport material)
16: Transparent electrode 17: Translucent covering 18: Second photoelectric conversion body 19: Intermediate layer

Claims

An electron transport material;
A dye located on the electron transport material and having a pentavalent phosphoporphyrin represented by the following general formula 1:
A hole transport material located on the dye;
A photoelectric conversion device comprising: a first photoelectric conversion body having:

(In the formula, R1 to R14 are optional substituents.)
2. The photoelectric conversion device according to claim 1, wherein at least one of R1 to R4 in the general formula 1 is a phenyl group having an electron-donating substituent.
The photoelectric conversion device according to claim 2, wherein the phenyl group is a (dialkylamino) phenyl group, an aminophenyl group, or a hydroxyphenyl group.
The photoelectric conversion device according to claim 1, wherein the electron transport material includes an oxide semiconductor, and the dye is attached to the oxide semiconductor.
The photoelectric conversion device according to claim 4, wherein at least one of R5 and R6 of the general formula 1 has a carboxyl group.
The photoelectric conversion device according to claim 1, further comprising a second photoelectric conversion body positioned on the first photoelectric conversion body and having a semiconductor layer.
The photoelectric conversion device according to claim 6, wherein the second photoelectric conversion body has an amorphous silicon layer.
A dye containing pentavalent phosphorus porphyrin represented by the following general formula 1,
A dye, wherein at least one of R1 to R4 is a phenyl group having an electron-donating substituent.

(In the formula, R1 to R14 are optional substituents.)
The dye according to claim 8, wherein the phenyl group is a (dialkylamino) phenyl group, an aminophenyl group, or a hydroxyphenyl group.
The dye according to claim 8, wherein at least one of R5 and R6 of the general formula 1 has a carboxyl group.