JP4969046B2 - Photoelectric conversion device and photovoltaic device using the same - Google Patents

Description

  The present invention relates to a photoelectric conversion device such as a solar cell or a light receiving element using a novel photoelectric conversion material capable of obtaining high photoelectric conversion efficiency, and a photovoltaic device using the photoelectric conversion device.

  A dye-sensitized solar cell, which is one of photoelectric conversion devices, is considered advantageous for cost reduction because it does not require high-temperature treatment or a vacuum device, and research and development have been promoted rapidly in recent years. In this dye-sensitized solar cell, for example, a porous titanium oxide layer obtained by sintering fine particles having a particle diameter of about 20 nm is provided on a conductive glass substrate, and the dye is applied to the particle surface of the porous titanium oxide layer. Using an electrode with monomolecular adsorption as a photo-active electrode, an electrolyte solution containing an iodine / iodide redox pair is filled between a counter electrode in which a platinum layer is formed on a glass substrate by sputtering, and this electrolyte solution is sealed. It has a stopped structure. By making such a porous structure, the surface area of the light working electrode can be increased by 1000 times or more, and light absorption by the adsorbing dye can be efficiently performed to generate photovoltaic power. As a result, the dye-sensitized solar cell has a photoelectric conversion efficiency of 10% or more. In addition, since the porous titanium oxide layer can be easily formed by a coating process, there is an advantage that the cost of the solar cell can be reduced, and its practical use is being studied.

Although it is a dye-sensitized solar cell having the advantages of high photoelectric conversion efficiency and low-cost production as described above, it cannot be said that the photoelectric conversion efficiency is sufficient for practical use. As a method for improving the photoelectric conversion efficiency, there is also a method of increasing the thickness of the light absorption layer, which is a porous titanium oxide layer on which a dye is adsorbed.
JP 2000-285974 A Japanese Patent Laid-Open No. 2004-74609

  Here, the photoelectric conversion apparatus 1 of a prior art is shown in FIG. In this photoelectric conversion device 1, a porous electron transporter layer 12 (porous titanium oxide layer) carrying a dye 13 is formed on a first conductive layer 11 formed on a transparent substrate 10, and this electron It comprises an electrolyte 14 which is a reverse conductivity type transporter formed so as to fill the transporter 12, a second conductive layer 17 carrying platinum or carbon, and a support 18.

  However, in this conventional photoelectric conversion device 1, when a conductive glass substrate or a conductive plastic substrate is used as the transparent substrate 10 and a porous titanium oxide layer is formed thereon, the conductive glass substrate and the porous titanium oxide are formed. Due to the difference in thermal expansion coefficient from the layer, the porous titanium oxide layer is peeled off (shown as the peeled portion 20), and the current path is interrupted, resulting in a problem that power generation efficiency is lowered. Further, there is a problem that the conductive glass substrate or the like warps due to the stress due to the difference in thermal expansion coefficient, and the conductive glass substrate or the like is cracked or deformed.

  In addition, in the case of the electron transport layer 12 formed by adding an organic material in order to suppress cracks, the number of vacancies increases, but the surface area of the titanium oxide portion of the electron transport layer 12 decreases, and the dye Since the amount of adsorption of 13 on titanium oxide is reduced, there is a problem that power generation efficiency is reduced.

  Therefore, the present invention has been completed in view of the above-mentioned problems in the prior art, and its purpose is to peel off a porous titanium oxide layer formed on a conductive glass substrate or a conductive plastic substrate, and to conduct electricity. It is to improve the power generation efficiency of the photoelectric conversion device by suppressing the warpage of the conductive glass substrate and the conductive plastic substrate, and to provide a photoelectric conversion device such as a solar cell or a light receiving element with high photoelectric conversion efficiency. .

The photoelectric conversion device of the present invention includes a conductive substrate functioning as one electrode, a plurality of convex portions formed on the main surface of the conductive substrate, and the main surface of the conductive substrate in contact with the convex portions. The porous semiconductor layer is formed on the surface and has an electrolyte and the other electrode, and the porous semiconductor layer extends from the convex portion to the surface. A plurality of grooves are formed.

  The photoelectric conversion device of the present invention is preferably characterized in that the groove is formed continuously over substantially the entire surface of the porous semiconductor layer.

  The photovoltaic power generation apparatus of the present invention is characterized in that the photoelectric conversion apparatus of the present invention is used as a power generation means, and the generated power of the power generation means is supplied to a load.

The photoelectric conversion device of the present invention was formed so that the conductive substrate functioning as one electrode, the convex portion formed on the main surface of the conductive substrate, and the main surface of the conductive substrate in contact with the convex portion , It has a porous semiconductor layer with a large number of photoexciters that perform photoelectric conversion on the surface, an electrolyte, and the other electrode, and the porous semiconductor layer has a plurality of grooves extending from the convex portion to the surface. The loss of the photoelectric conversion area because such a plurality of grooves can relieve stress generated between the porous semiconductor layer and the conductive substrate and suppress the peeling of the porous semiconductor layer. This is advantageous in achieving both high conversion efficiency and low cost of the photoelectric conversion device.

  In the photoelectric conversion device of the present invention, preferably, since the groove is continuously formed over substantially the entire surface of the porous semiconductor layer, partial peeling of the porous semiconductor layer can also be suppressed. Since the entire short circuit and leakage between the conductive substrate functioning as an electrode and the other electrode are suppressed, it is advantageous in achieving both high conversion efficiency and low cost of the photoelectric conversion device.

  Since the photovoltaic device of the present invention uses the photoelectric conversion device of the present invention as a power generation means and supplies the generated power of the power generation means to a load, a highly efficient and durable photovoltaic power generation device is provided. It can be provided at low cost.

  Exemplary embodiments of a photoelectric conversion device and a photovoltaic device according to the present invention will be described in detail below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same member in drawing.

  FIG. 1 is a cross-sectional view schematically illustrating a photoelectric conversion device that forms the basic structure of a dye-sensitized solar cell. In FIG. 1, an arrow L in the figure indicates a direction in which light enters.

  1 includes a metal oxide in which a dye 13 as a photoexciter is adsorbed on a translucent substrate 10 (conductive substrate) on which a first conductive layer 11 (one electrode) is formed. An electron transport layer (metal oxide semiconductor layer: porous semiconductor layer) 12 which is a one-conductivity type transporter made of a semiconductor is disposed in a state where it is present in an electrolyte 14 which is the other conductivity-type transporter. And This configuration forms a dye-sensitized photoelectric converter that performs photoelectric conversion by the sensitizing action of the dye 13, and this dye-sensitized photoelectric converter is formed on the first conductive layer 11 to form the dye 13. A porous electron transporter layer 12 that is supported, an electrolyte 14 that is a reverse conductivity type transporter formed so as to fill the electron transporter layer 12, and a second conductive layer as the other electrode that supports platinum or carbon. 17 and a support 18. The second conductive layer 17 and the support 18 may be a metal substrate carrying platinum or carbon. Further, when the support 18 is transparent, light incident from the direction opposite to the direction of light incidence indicated by the arrow L in the drawing may be used.

  Next, each structure of the photoelectric conversion apparatus 1 mentioned above is demonstrated in detail.

<Translucent substrate>
As the translucent substrate 10, resin substrates made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, polycarbonate, etc., inorganic substrates made of white plate glass, soda glass, borosilicate glass, ceramics, etc., organic-inorganic hybrids Sheets are good.

<Conductive layer>
As the first conductive layer 11 and the second conductive layer (the other electrode) 17, a tin-doped indium oxide film (ITO film) or an impurity-doped indium oxide film produced by a low-temperature growth sputtering method or a low-temperature spray pyrolysis method (In ₂ O ₃ film) or the like is preferable. In addition, an impurity-doped zinc oxide (ZnO) film or the like produced by a solution growth method may be used, and these may be stacked and used. Alternatively, a fluorine-doped tin oxide (SnO ₂ : F) film formed by a thermal CVD method may be used. In addition, an impurity-doped indium oxide (In ₂ O ₃ ) film or the like can be used. Examples of other film forming methods include a vacuum deposition method, an ion plating method, a dip coating method, and a sol-gel method. Forming irregularities in the order of the wavelength of incident light on the surface by these film forming methods can provide a light confinement effect, which is more preferable. The first transparent conductive layer 15 may be a thin metal film such as Au, Pd, or Al formed by vacuum deposition or sputtering, a multilayer laminate such as Ti / ITO / Ti, or a metal mesh electrode / A composite such as ITO may be used.

<Electron transporter layer as porous semiconductor layer>
The electron transport layer 12 which is a one-conductivity transporter as the porous semiconductor layer is preferably an electron transport layer (n-type metal oxide semiconductor) such as porous titanium oxide. Further, the electron transporter layer 12 is preferably a granular body, a linear body such as a needle-shaped body, a tube-shaped body, a columnar body, or a combination of these various linear bodies.

  By using a porous body for the electron transport layer 12, the bonding area between the granular bodies or between the linear bodies is expanded, the surface area for supporting the dye 13 is increased, and the photoelectric conversion efficiency can be increased. In addition, by making the electron transport layer 12 a porous body, the surface of the dye-sensitized photoelectric conversion body has an uneven shape, bringing a light confinement effect to the thin film photoelectric conversion body and the dye-sensitized photoelectric conversion body, Photoelectric conversion efficiency can be further increased.

Titanium oxide (TiO ₂ ) is optimal as the material and composition of the metal oxide semiconductor forming the electron transport layer 12, and titanium (Ti), zinc (Zn), tin (Sn) are the other materials and compositions. ), Niobium (Nb), indium (In), yttrium (Y), lanthanum (La), zirconium (Zr), tantalum (Ta), hafnium (Hf), strontium (Sr), barium (Ba), calcium (Ca) ), An oxide semiconductor composed of at least one metal element such as vanadium (V) is preferable. Moreover, you may contain 1 or more types of nonmetallic elements, such as nitrogen (N), carbon (C), fluorine (F), sulfur (S), chlorine (Cl), and phosphorus (P). All of the above titanium oxides and the like are preferable because the electronic energy band gap is in the range of 2 to 5 eV larger than the energy of visible light. Further, the metal oxide semiconductor is preferably an n-type semiconductor whose conduction band is lower than that of the dye 13 in the electron energy level.

  This metal oxide semiconductor should have a porosity of 20 to 80%, more preferably a porous body of 40 to 60%. This is because the porosity of this degree of porosity can increase the surface area of the light working electrode by 1000 times or more, and light absorption, power generation and electron conduction can be performed efficiently. The shape of the porous body is preferably a shape having a large surface area and low electrical resistance, and is usually preferably composed of fine particles or fine lines. The average particle diameter or average wire diameter is preferably 5 to 500 nm, and more preferably 10 to 200 nm. Here, the lower limit of the average particle diameter or the average wire diameter in the range of 5 to 500 nm is that if it is less than this, it is difficult to refine the material. If the upper limit is exceeded, the junction area becomes smaller and the photocurrent is reduced. This is because is significantly reduced.

  Further, the thickness of the electron transporter layer 12 is preferably 0.1 to 50 μm, more preferably 1 μm to 20 μm. The lower limit of the thickness of the electron transporter layer 12 in the range of 0.1 to 50 μm is that if the thickness is smaller than this, the photoelectric conversion action becomes extremely small and practical use becomes difficult, and the upper limit exceeds this value. When the thickness becomes thicker, the electron transporter layer 12 is cracked, the electron transporter layer 12 is peeled off from the translucent substrate 10, the electrical resistance between the first conductive layer 11 is increased, This is because the light is not transmitted and light is not incident, and the photoelectric conversion action is remarkably reduced to make practical use difficult.

In the manufacturing method of titanium oxide as a metal oxide semiconductor, first, acetylacetone is added to a TiO ₂ anatase powder, and then kneaded with deionized water to prepare a titanium oxide paste stabilized with a surfactant. The prepared paste is applied onto the surface of the first conductive layer 11 at a constant speed by a doctor blade method, and heated at a rate of 2 to 20 ° C./min in the atmosphere to a temperature of 300 to 600 ° C., preferably 400 The electron transporter layer 12 composed of porous titanium oxide is formed by heat treatment at ˜500 ° C. for 10 to 60 minutes, preferably 20 to 40 minutes. This technique is simple and effective when it can be formed in advance on the heat-resistant translucent substrate 10 and the first conductive layer 11 as shown in FIG.

As the film growth method of the metal oxide semiconductor such as titanium oxide, since it can be processed at a low temperature, the electrodeposition method, electrophoretic electrodeposition method, hydrothermal synthesis method, etc. are preferable. An irradiation process or the like is preferably performed. As the metal oxide semiconductor forming the electron transport layer 12 in consideration of these film growth methods, porous ZnO by an electrodeposition method, porous TiO ₂ by a migration electrodeposition method, or the like is preferable.

<Electrolyte>
The material of the electrolyte 14 which is the other conductive type transporter formed so as to fill the porous electron transport layer 12 includes transparent conductive oxide, electrolyte solution, electrolyte such as gel electrolyte and solid electrolyte, organic hole Examples include transport agents and ultra-thin metal. In particular, a hole electrolyte (p-type semiconductor) such as a gel electrolyte, a liquid electrolyte, a solid electrolyte, or an electrolytic salt is preferable. Among these, the electrolytic solution shows the best carrier mobility. However, in the case of a liquid, there are problems such as liquid leakage.

The transparent conductive oxide as the electrolyte 14 is preferably a compound semiconductor containing GaP, NiO, CoO, FeO, Bi ₂ O ₃ , MoO ₂ , Cr ₂ O ₃ or the like and monovalent copper. A compound semiconductor containing copper is preferable. As the compound semiconductor, CuI, CuInSe ₂ , Cu ₂ O, CuSCN, CuS, CuInS ₂ , CuAlSe _{2 and the} like are preferable, among which CuI and CuSCN are preferable, and CuI is most preferable because it is easy to manufacture.

  As the electrolyte solution, a quaternary ammonium salt, a Li salt, or the like is used. As the composition of the electrolyte solution, for example, a solution prepared by mixing ethylene carbonate, acetonitrile, methoxypropionitrile, or the like with tetrapropylammonium iodide, lithium iodide, iodine, or the like can be used.

  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 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 into 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 included in the oxide semiconductor layer, 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 ion conductive solid electrolyte, a solid electrolyte having a polymer chain such as polyethylene oxide, polyethylene oxide, or polyethylene and having a salt such as sulfonimidazolium salt, tetracyanoquinodimethane salt, or dicyanoquinodiimine salt is preferable. As the molten salt of iodide, an iodide such as an imidazolium salt, a quaternary ammonium salt, an isoxazolidinium salt, an isothiazolidinium salt, a pyrazolidium salt, a pyrrolidinium salt, or a pyridinium salt can be used.

  Examples of the molten salt of iodide include 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- Examples thereof include 3-isopropylimidazolium iodide and pyrrolidinium iodide.

  Examples of the electrolyte 14 that functions as an organic hole transport agent include triphenyldiamine (TPD1, TPD2, TPD3) and OMeTAD (2,2 ′, 7,7′-tetrakis (N, N-di-p-methoxyphenyl-amine). 9,9′-spirobifluorene) and the like.

<Dye>
The dye 13 supported on the electron transporter layer 12 may be any dye 13 that absorbs light between wavelengths of 300 to 2000 nm of sunlight and is adsorbed on the electron transporter layer 12. As the material of the dye 13, inorganic semiconductors such as silicon, gallium arsenide, indium phosphide, cadmium selenium, cadmium sulfide, CuInSe, inorganic pigments such as chromium oxide, iron oxide, nickel oxide, Ru complex, porphyrin, phthalocyanine, Organic pigments such as merocyanine, coumarin and indoline are preferred.

  In addition, it is effective that the dye 13 has at least one adsorption substituent, that is, a carboxyl group, a sulfonyl group, a hydroxamic acid group, an alkoxy group, an aryl group, a phosphoryl group, or the like as a substituent. Here, the adsorption substituent may be any one that can strongly chemisorb to the electron transport layer 12 and can easily transfer charges from the excited dye 13 to the electron transport layer 12.

Further, in order to efficiently capture electrons from the electrolyte 14, the dye 13 has at least one electron donating substituent, that is, an alkyl group such as a methyl group, an ethyl group or an isopropyl group, or an alkoxy group such as a methoxy group or an ethoxy group. Group, aryl groups such as phenyl and naphthyl groups, halogen groups such as chlorine and bromine, hydroxy groups, amino groups, thiocyanate groups, cyano groups, tertiary butyl groups, 3,5-ditertiary butylphenyl groups and the like as substituents It is effective to have. Here, the electron-donating substituent can be captured efficiently electrons from the electrolyte 14, the reduction of the electrolyte 14, for example if I using iodine redox ^- long as it can easily charge transfer to the dye 13 from That's fine.

  As a method of adsorbing the dye 13 to the electron transport layer 12 (porous metal oxide semiconductor), a method of immersing the translucent substrate 10 on which the electron transport layer 12 is formed in a solution in which the dye 13 is dissolved Is mentioned. When the translucent substrate 10 on which the electron transport layer 12 is formed 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 is at atmospheric pressure, The temperature may be room temperature, and the immersion time 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.

  Further, after the dye 13 is adsorbed to the metal oxide semiconductor powder to be the electron transport layer 12, the metal oxide semiconductor powder or paste is applied onto the first conductive layer 11, and the dye 13 Examples of the method include solidification at a temperature and atmosphere at which no alteration or decomposition occurs. When the dye 13 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 under atmospheric pressure, the temperature may be room temperature, and the immersion time is the type of the dye 13 , And can be appropriately adjusted depending on the type of solvent, the concentration of the solution, the temperature, and the like.

  Thus, the dye 13 can be adsorbed on the electron transporter layer 12 made of a porous metal oxide semiconductor.

  Examples of the solvent used for dissolving the dye 13 include a mixture of one or more alcohols such as ethanol, ketones such as acetone, ethers such as diethyl ether, nitrogen compounds such as acetonitrile, and the like.

Further, the concentration of the dye 13 in the solution is preferably about 5 × 10 ⁻⁵ to 2 × 10 ⁻³ mol / l (liter: 1000 cc).

  Further, in order to suppress aggregation of the dye 13, a weakly basic compound such as tertiary butyl pyridine or a weakly acidic compound such as deoxycholic acid is dissolved in the dye 13 solution, and the dye 13 and the additive are combined. A method of co-adsorption on the electron transporter layer 12 may be used. Further, in addition to such a method, after the dye 13 is adsorbed on the electron transporter layer 12, the electron transporter layer 12 is immersed in the additive solution to adsorb the additive. It is possible to suppress the recombination reaction between the dye 13 in which the electrons injected into the layer 12 are in the oxidized state and the electron injected into the electron transport layer 12 with the oxidized substance in the electrolyte 14, that is, the occurrence of electron leakage. The photoelectric conversion efficiency can be improved.

<Support>
The support (support substrate) 18 is a resin substrate made of fluorine resin, silicon polyester resin, high weather resistance polyester resin, polyvinyl chloride resin, PET, PEN, polyimide, polycarbonate, etc., white plate glass, soda glass, borosilicate glass Inorganic substrates made of ceramics, organic-inorganic hybrid sheets, and metal plates made of metals such as aluminum, titanium, and stainless steel are preferable.

<Underlayer>
Although the underlying layer is not shown, in the configuration of FIG. 1, a porous one-conducting transporter is disposed between the first conductive layer 11 and the one-conducting electron-transporting layer 12 in the porous body. If a thin dense layer is inserted, the reverse current may not flow.

<Catalyst layer>
Although the catalyst layer is not shown, in the configuration of FIG. 1, an ultrathin film such as platinum or carbon is placed between the second conductive layer 17 and the electrolyte 14 which is a reverse porous body and the other conductive type transporter. When inserted, the movement of holes is improved.

  Note that a collector electrode may be provided on each of the first conductive layer 11 and the second conductive layer 17 to reduce the electric resistance.

  Thus, according to the photoelectric conversion device of the present invention, since a number of grooves are formed in the porous semiconductor layer, the stress between the porous semiconductor layer and the conductive substrate is relieved, and the conductivity of the porous semiconductor layer is reduced. Since peeling from the conductive substrate can be suppressed, loss of the photoelectric conversion area can be suppressed, and high conversion efficiency and cost reduction of the photoelectric conversion device can be achieved.

  Hereinafter, the present invention will be described based on specific examples.

  3A and 3B are a cross-sectional view and a plan view of the photoelectric conversion device according to the first embodiment of the present invention. As the conductive substrate, a transparent substrate 10 made of glass in which a transparent first conductive layer 11 made of fluorine-doped tin oxide is formed on the main surface is used, and a porous material is formed on the first conductive layer 11. An electron transporter layer 12 made of titanium oxide was formed.

  The electron transporter layer 12 was formed as follows. First, acetylacetone was added to titanium oxide anatase powder (“P25” manufactured by Nippon Aerosil Co., Ltd.), and then kneaded with deionized water to prepare a titanium oxide paste stabilized with a surfactant. The prepared paste was applied onto the first conductive layer 11 of the translucent substrate 10 at a constant scanning speed by a doctor blade method. At this time, the composition ratio, viscosity, and scanning speed of the paste were adjusted so that the film thickness after firing was 10 μm. After the translucent substrate 10 on which the paste layer is formed is dried in the air, it is heated from room temperature to 450 ° C. for 1 hour in an electric furnace in an air atmosphere, and baked in the electric furnace for 45 minutes at 450 ° C. As shown in the figure, many crack-like grooves could be formed in the porous electron transport layer 12.

  Thereafter, the translucent substrate 10 provided with the porous electron transporter layer 12 is immersed in an aqueous solution of titanium tetrachloride, dried, heated to 450 ° C. for 1 hour, and heated in an electric furnace to 450 ° C., 30 ° C. The translucent substrate 10 provided with the porous electron transporter layer 12 was heated for 5 minutes to fire the electron transporter layer 12.

  As a dye, a ruthenium complex (“N719” manufactured by Solaronics) was used, and acetonitrile and t-butanol (1: 1 by volume) were used as solvents used to dissolve the dye, and an electron transporter layer 12 was formed. The light-transmitting substrate 10 was immersed in a solution (0.3 mmol / l) in which the dye was dissolved for 12 hours so that the dye was supported on the electron transporter layer 12. Thereafter, the translucent substrate 10 was washed with acetonitrile and then dried.

As a hole transporting layer (electrolyte) 14 was prepared 0.1 mol / l of LiI, stirring the solution until an _{I 2} of 0.05 mol / l dissolved electrolyte placed in acetonitrile (electrolyte).

  The second conductive layer 17 was formed by depositing a Pt layer with a thickness of 50 nm by a sputtering method on the main surface of a glass support 18 on which a transparent conductive layer made of fluorine-doped tin oxide was formed.

  The translucent substrate 10 on which the dye is adsorbed on the electron transport layer 12 and the support 18 on which the second conductive layer 17 is formed are opposed to the electron transport layer 12 and the second conductive layer 17. In the same manner, a sheet-like spacer made of a thermoplastic resin (“HIMILAN” manufactured by Mitsui DuPont Polychemical Co., Ltd.) is interposed between the support 18 and the translucent substrate 10. An electrolytic solution was injected from the opening and sealed with a thermoplastic resin, an ultraviolet curable resin, or a thermosetting resin, thereby forming a cell of a photoelectric conversion device.

A conventional photoelectric conversion device in which the electron transport layer 12 made of titanium oxide is partially peeled from the translucent substrate 10 is measured at 100 mW / cm ² in AM1.5, and as a result, the open circuit voltage Voc is 0.651 V, short-circuited. The current Jsc was 4.22 mA / cm ² , the shape factor FF was 0.581, the photoelectric conversion efficiency was 1.59%, and the photoelectric conversion efficiency was low.

The photoelectric conversion device of Example 1 described above was measured at 100 mW / cm ² at AM 1.5. As a result, the open circuit voltage Voc was 0.669 V, the short circuit current Jsc was 9.19 mA / cm ² , the form factor FF was 0.660, The conversion efficiency was 4.06%, and a significant improvement in photoelectric conversion efficiency was achieved.

  In the second embodiment, an electron transport made of porous titanium oxide is formed on a glass transparent substrate 10 on which a transparent first conductive layer 11 made of fluorine-doped tin oxide is formed as a conductive substrate. The body layer 12 having a pattern formed thereon was used. 4A and 4B are a cross-sectional view and a plan view of the photoelectric conversion device according to the second embodiment.

  The electron transporter layer 12 was formed as follows. In the same manner as in Example 1, after adding acetylacetone to anatase powder of titanium oxide (“P25” manufactured by Nippon Aerosil Co., Ltd.), a titanium oxide paste kneaded with deionized water and stabilized with a surfactant is used. Produced.

  Next, the prepared paste is screen-printed on a glass transparent substrate 10 on which the first conductive layer 11 made of fluorine-doped tin oxide is formed. The titanium oxide paste is 1 mm in pitch and 0.1 mm in gap. Pattern formation. Here, the pitch is the interval between the lateral grooves 19 in FIG. 4B, and the interval is the width of the lateral groove 19 in FIG. 4B.

  Then, the composition ratio, viscosity, and scanning speed of the paste were adjusted so that the film thickness after firing was 10 μm. After the light-transmitting substrate 10 on which the paste layer was formed was dried in the air, the temperature was raised from room temperature to 450 ° C. in an air atmosphere in an electric furnace in 1 hour, and baked in an electric furnace at 450 ° C. for 30 minutes. No peeling was observed in the electron transport layer 12 thus obtained.

  Thereafter, in the same manner as in Example 1, the translucent substrate 10 was immersed in an aqueous titanium tetrachloride solution and dried, then heated to 450 ° C. for 1 hour, and the porous electron transport was performed in an electric furnace at 450 ° C. for 30 minutes. The translucent substrate 10 provided with the body layer 12 was heated to fire the electron transport layer 12.

  As in Example 1, as in Example 1, a ruthenium complex (“N719” manufactured by Solaronics) was used, and acetonitrile and t-butanol (1: 1 by volume) were used as solvents used to dissolve the dye. The light-transmitting substrate 10 on which the transporter layer 12 was formed was immersed in a solution (0.3 mmol / l) in which the dye was dissolved for 12 hours so that the dye was supported on the electron transporter layer 12. Thereafter, the translucent substrate 10 was washed with acetonitrile and then dried.

As the electrolyte 14 is a hole transport layer, in the same manner as in Example 1 A solution was prepared by stirring until 0.1 mol / l of LiI, electrolyte 14 I ₂ placed in acetonitrile 0.05 mol / l is dissolved.

  The second conductive layer 17 was formed by depositing a Pt layer with a thickness of 50 nm on the main surface of a glass support 18 on which a transparent conductive layer made of fluorine-doped tin oxide was formed by a sputtering method.

  The translucent substrate 10 on which the dye is adsorbed on the electron transport layer 12 and the support 18 on which the second conductive layer 17 is formed are opposed to the electron transport layer 12 and the second conductive layer 17. As shown, the sheet 18 is formed on the support 18 or the translucent substrate 10 with a sheet-like spacer made of thermoplastic resin (“HIMILAN” manufactured by Mitsui DuPont Polychemical Co., Ltd.) interposed therebetween. An electrolytic solution was injected from the opened opening and sealed with a thermoplastic resin, an ultraviolet curable resin, or a thermosetting resin to form a cell of a photoelectric conversion device.

The photoelectric conversion device thus obtained was measured at 100 mW / cm ² at AM 1.5. As a result, the open circuit voltage Voc was 0.670 V, the short circuit current Jsc was 7.81 mA / cm ² , the form factor FF was 0.650, and the conversion efficiency was 3.40. %, And a significant improvement in photoelectric conversion efficiency was achieved.

  In Example 3, as the conductive substrate, a convex portion such as a glass layer is formed on the transparent first conductive layer 11 made of fluorine-doped tin oxide formed on the main surface of the glass transparent substrate 10. After forming the pattern, an electron transporter layer 12 made of porous titanium oxide was formed.

  5A and 5B are a cross-sectional view and a plan view of the photoelectric conversion device according to the third embodiment.

  On the first conductive layer 11 of the light-transmitting substrate 10 made of glass on which the first conductive layer 11 of fluorine-doped tin oxide is formed, a glass paste is used to form a bank (projection) with a pitch of 1 mm and a width of 0.1 mm. ) Was printed and fired at 510 ° C. for 5 minutes to form the convex portion 21. Here, the pitch is the interval between the convex portions 21 in the horizontal direction in FIG. 5B, and the width is the width of the convex portions 21 in the horizontal direction in FIG.

  The electron transporter layer 12 was formed as follows. In the same manner as in Example 1, after adding acetylacetone to anatase powder of titanium oxide (“P25” manufactured by Nippon Aerosil Co., Ltd.), a titanium oxide paste kneaded with deionized water and stabilized with a surfactant is used. Produced. And using this paste, it apply | coated on the 1st conductive layer 11 with the constant scanning speed by the doctor blade method. The composition ratio, viscosity, and scanning speed of the paste were adjusted so that the film thickness after firing was 10 μm. After the light-transmitting substrate 10 on which the paste layer was formed was dried in the air, the temperature was raised from room temperature to 450 ° C. in an air atmosphere in an electric furnace in 1 hour and baked in an electric furnace at 450 ° C. for 30 minutes. No peeling was observed in the electron transport layer 12 thus obtained.

  Further, as shown in FIGS. 5A and 5B, a crack-like groove 19 a was formed on the electron transport layer 12 from the convex portion 21 to the surface of the electron transport layer 12.

  Thereafter, in the same manner as in Example 1, the translucent substrate 10 was immersed in an aqueous titanium tetrachloride solution and dried, then heated to 450 ° C. for 1 hour, and the porous electrons were heated in an electric furnace at 450 ° C. for 30 minutes. The light-transmitting substrate 10 provided with the transporter layer 12 was heated to fire the electron transporter layer 12.

  As in Example 1, as in Example 1, a ruthenium complex (“N719” manufactured by Solaronics) was used, and acetonitrile and t-butanol (1: 1 by volume) were used as solvents used to dissolve the dye. The light-transmitting substrate 10 on which the transporter layer 12 was formed was immersed in a solution (0.3 mmol / l) in which the dye was dissolved for 12 hours so that the dye was supported on the electron transporter layer 12. Thereafter, the translucent substrate 10 was washed with acetonitrile and then dried.

As the electrolyte 14 as a hole transport layer, in the same manner as in Example 1, 0.1 mol / l of LiI, and stirred an I ₂ of 0.05 mol / l until dissolution is electrolyte 14 was placed in acetonitrile solution (electrolyte solution) Was prepared.

  The second conductive layer 17 was formed by depositing a Pt layer with a thickness of 50 nm on the main surface of a glass support 18 on which a transparent conductive layer made of fluorine-doped tin oxide was formed by a sputtering method.

  The translucent substrate 10 on which the dye is adsorbed on the electron transport layer 12 and the support 18 on which the second conductive layer 17 is formed are opposed to the electron transport layer 12 and the second conductive layer 17. As shown, the sheet 18 is formed on the support 18 or the translucent substrate 10 with a sheet-like spacer made of thermoplastic resin (“HIMILAN” manufactured by Mitsui DuPont Polychemical Co., Ltd.) interposed therebetween. An electrolytic solution was injected from the opened opening and sealed with a thermoplastic resin, an ultraviolet curable resin, or a thermosetting resin to form a cell of a photoelectric conversion device.

The photoelectric conversion device thus obtained was measured at 100 mW / cm ² at AM 1.5. As a result, the open circuit voltage Voc was 0.668 V, the short circuit current Jsc was 7.90 mA / cm ² , the form factor FF was 0.670, and the conversion efficiency was 3.54. %, And a significant improvement in photoelectric conversion efficiency was achieved.

  In Example 3 described above, the convex portion 21 for forming irregularities was formed using glass frit. However, the material of the convex portion 21 has a thermal expansion coefficient larger than that of the electron transport layer 12. Is good. Further, in the above-described third embodiment, a recess for forming unevenness may be formed by partially etching the first conductive layer 11.

It is sectional drawing which shows typically an example of embodiment of the photoelectric conversion apparatus of this invention. It is sectional drawing which shows an example of the conventional photoelectric conversion apparatus typically. It is sectional drawing which shows typically an example of embodiment of the photoelectric conversion apparatus of this invention. (A), (b) is sectional drawing and the top view which show typically the other example of embodiment of the photoelectric conversion apparatus of this invention. (A), (b) is sectional drawing and the top view which show typically the other example of embodiment of the photoelectric conversion apparatus of this invention.

Explanation of symbols

1: Photoelectric conversion device
10: Translucent substrate
11: First conductive layer
12: Electron transporter layer
13: Dye
14: Electrolyte
17: Second conductive layer
18: Support
19: Groove
21: Convex

Claims (3)

Conductive substrate that functions as one electrode, a plurality of convex portions formed on the main surface of the conductive substrate, and photoelectric conversion formed on the main surface of the conductive substrate so as to be in contact with the convex portions. The porous semiconductor layer has a porous semiconductor layer with a large number of photoexciters adhered to the surface, an electrolyte, and the other electrode, and the porous semiconductor layer has a plurality of grooves extending from the convex portions to the surface . A photoelectric conversion device characterized by the above.   The photoelectric conversion device according to claim 1, wherein the groove is formed continuously over substantially the entire surface of the porous semiconductor layer.   A photovoltaic device comprising the photoelectric conversion device according to claim 1 or 2 as a power generation means, and the power generated by the power generation means is supplied to a load.

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