JP4291542B2 - Oxide semiconductor electrode for photoelectric conversion and dye-sensitized solar cell - Google Patents

Description

【０１０８】
表１に示される実施例１と比較例１との対比結果、実施例２と比較例２との対比結果、および実施例３と比較例３との対比結果、ならびに実施例１と比較例４との対比結果より、本発明の実施例サンプルは、各比較例サンプルと比べて格段と高い光電変換効率が得られることが確認できた。
【０１０９】
【発明の効果】
上記の結果より本発明の効果は明らかである。すなわち、本発明は、表面に色素が形成された光電変換用酸化物半導体電極と、これと対をなす対向電極と、それらの電極に接触する電荷移動層とを有する色素増感型太陽電池であって、前記光電変換用酸化物半導体電極は、導電性表面を有する樹脂基板と、導電性表面の上に形成された酸化物半導体膜と、この酸化物半導体膜の上に形成された有機色素を有し、前記酸化物半導体膜は、酸化物半導体微粒子のゾルまたはスラリーをスプレー塗布して形成されるとともに、当該酸化物半導体膜は、有機色素を形成させる前の段階で、中和処理溶液との接触処理がなされているように構成されているので、樹脂基板を用いて酸化物半導体膜の低温処理しか行なわれなくとも、エネルギ−変換効率の格段の向上が発現する。また、樹脂基板を用いることにより、電池の軽量化、低コスト化も図られる。さらには量産化に向けて環境や人体に及ぼす悪影響を低減することが可能となる。
【図面の簡単な説明】
【図１】本発明の色素増感型太陽電池の模式的構成例を示した図面である。
【符号の説明】
１…色素増感型太陽電池
４…酸化物半導体膜
５…電荷移動層
７…有機色素膜
１０…光電変換用酸化物半導体電極
２０…基板
２２…透明導電性層
３０…対向電極[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oxide semiconductor electrode for photoelectric conversion used for photoelectric conversion, and a dye-sensitized solar cell using the electrode.
[0002]
[Prior art]
It has already been reported by Gretzell et al. That a dye-sensitized solar cell having performance comparable to that of an amorphous silicon solar cell can be obtained by using a porous titanium oxide electrode (J. Am. Chem. Soc. 115). (1993) 6382).
[0003]
Furthermore, in addition to titanium oxide, it has been reported that photoelectric conversion ability is exhibited in various oxide semiconductors such as oxide semiconductors such as niobium oxide, zinc oxide, tin oxide and indium oxide, or a mixed system thereof. Yes.
[0004]
As a method for producing these oxide semiconductor electrodes, a method is generally used in which a sol liquid or slurry liquid of oxide semiconductor fine particles is applied to the surface of a conductive substrate to form a film.
[0005]
In order for the oxide semiconductor electrode to fully perform its function, a strong bond between the oxide semiconductor particles and a strong bond between the oxide semiconductor particles and the surface of the conductive substrate are very important. It is also very important to increase the dye adsorption surface area involved in photoelectric conversion by making the oxide semiconductor film porous and sponge-like, and to improve the permeability of the electrolyte that is the charge transfer layer It is.
[0006]
In order to achieve these objects, an organic binder component such as polyethylene glycol is added in an appropriate amount to the oxide semiconductor fine particle sol and slurry to prepare a coating solution, and this coating solution is applied onto a substrate. A method of forming a film by firing at a high temperature of 400 ° C. or higher is generally used.
[0007]
In other words, the oxide semiconductor film is made porous by enhancing the bonding between the oxide semiconductor particles and between the oxide semiconductor particles and the conductive surface by heating to a high temperature, and by decomposing and evaporating the organic binder component. can do.
[0008]
However, such high-temperature firing has a problem in that the use is limited because a resin material cannot be used as the substrate. In addition, high temperature firing uses a large amount of energy and has many negative factors in terms of the environment.
[0009]
In view of such problems, Japanese Patent Application Laid-Open No. 2001-357896 discloses (i) irradiation with ultraviolet light of 400 nm or less, or (ii) heating at 50 ° C. or more and less than 350 ° C. as a treatment method instead of high-temperature baking. Various processing methods such as (iii) microwave irradiation have been proposed.
[0010]
[Problems to be solved by the invention]
However, only by using these methods, the organic binder component contained in the coating solution as an essential component is insufficiently removed, and the remaining organic binder component adversely deteriorates battery characteristics. For example, when polyethylene glycol having a molecular weight of 20000 is used as the organic binder component, the thermal decomposition temperature is in the range of 250 to 300 ° C. Therefore, if heat treatment is carried out in this temperature range, the polyethylene glycol is decomposed and evaporated, but the damage to the resin substrate becomes very large.
[0011]
In addition, even in the photo-oxidation reaction decomposition by irradiation with ultraviolet light, it is necessary to irradiate ultraviolet light for a long time to completely decompose and remove the contained organic binder component, which is realistic considering productivity. I can't say that.
[0012]
In addition, in microwave heating, local concentration of microwaves on the conductive surface (such as a transparent electrode installed on the substrate) occurs, causing the occurrence of sparks, cracks in the transparent electrode, Many problems such as damage can occur.
[0013]
In addition, it has been proposed to perform a combination of these methods. However, the amount of treatment on the resin substrate is still large, and an improvement in the manufacturing method of the oxide semiconductor film itself is desired.
[0014]
By the way, the dispersibility of the oxide semiconductor fine particles in the sol liquid or slurry liquid used for manufacturing the oxide semiconductor film greatly affects the photoelectric conversion characteristics of the manufactured oxide semiconductor electrode. The higher the dispersion level is (the more the aggregation is suppressed), the greater the surface energy of the surface of the oxide semiconductor fine particles. This improves the photoelectric conversion characteristics. In addition, suppressing aggregation of the oxide semiconductor particles leads to suppression of light scattering, and is important in terms of improving light permeability into the oxide semiconductor film.
[0015]
As a method for improving the dispersibility of oxide semiconductor fine particles in a sol or slurry, a method is generally used in which acid or alkali is added and the pH of the coating solution is kept as far as possible from the pH near the isoelectric point of the oxide semiconductor fine particles. Used for.
[0016]
However, when such an acid or alkali addition method is used, an improvement in the dispersibility of the coating liquid can be expected, but depending on the setting of the manufacturing conditions in the subsequent manufacturing process, the photoelectric conversion characteristics are not so improved. On the contrary, the phenomenon that the photoelectric conversion characteristic is deteriorated frequently occurs.
[0017]
In addition, the acidic gas or alkaline gas generated when the coating film is fired at a high temperature may adversely affect the corrosion of the firing furnace, the environment, or the human body, and this tendency is particularly noticeable in mass production. It can be a problem.
[0018]
The present invention was devised under such circumstances, and its purpose is to enable the use of a so-called resin material substrate, which is excellent in energy conversion efficiency, and further to the environment for mass production. An oxide semiconductor electrode for photoelectric conversion and a dye-sensitized solar cell using the same are provided.
[0019]
[Means for Solving the Problems]
Based on the premise of using a substrate made of a resin material, the present inventors have intensively studied on the formation of an oxide semiconductor film capable of obtaining good energy conversion efficiency by low-temperature treatment, and as a result, have come up with the present invention. .
[0020]
That is, the present invention relates to a photoelectric conversion oxide having a resin substrate having a conductive surface, an oxide semiconductor film formed on the conductive surface, and an organic dye formed on the oxide semiconductor film. A semiconductor electrode, wherein the oxide semiconductor film is formed by spraying a sol or slurry of oxide semiconductor fine particles, and the oxide semiconductor film is neutralized at a stage before forming an organic dye. It is comprised so that the contact process with a process solution may be made.
[0021]
The present invention is a dye-sensitized solar cell having an oxide semiconductor electrode for photoelectric conversion having a dye formed on its surface, a counter electrode paired therewith, and a charge transfer layer in contact with these electrodes. The oxide semiconductor electrode for photoelectric conversion has a resin substrate having a conductive surface, an oxide semiconductor film formed on the conductive surface, and an organic dye formed on the oxide semiconductor film. The oxide semiconductor film is formed by spray-coating a sol or slurry of oxide semiconductor fine particles, and the oxide semiconductor film is formed with a neutralization treatment solution before the formation of the organic dye. It is configured such that contact processing is performed.
[0022]
Moreover, the said neutralization process solution in this invention is comprised so that an acid or an alkali may be included.
[0023]
The sol or slurry of oxide semiconductor fine particles to be spray-coated in the present invention is configured so as not to contain an organic binder component.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the dye-sensitized solar cell of the present invention will be described in detail. FIG. 1 shows a schematic configuration example of the dye-sensitized solar cell of the present invention. As shown in FIG. 1, the dye-sensitized solar cell 1 of the present invention has a configuration in which two electrodes 10 and 30 are disposed to face each other with a charge transfer layer 5 interposed therebetween, for example. One electrode 10 of the two electrodes is an oxide semiconductor electrode 10 for photoelectric conversion provided with an organic dye, which includes, for example, a resin substrate 20 and a transparent conductive film 22 formed thereon, The oxide semiconductor film 4 is formed on the surface of the conductive film 22, and the organic dye film 7 is bonded to the surface of the oxide semiconductor film.
[0025]
Next, the oxide semiconductor electrode 10 for photoelectric conversion provided with an organic dye will be described. As described above, this is, for example, the resin substrate 20, the transparent conductive film 22 formed thereon, the oxide semiconductor film 4 formed on the surface of the conductive film 22, and the oxide semiconductor film. And an organic dye film 7 bonded to the surface.
[0026]
Hereinafter, each individual component requirement will be described.
Configuration of resin substrate having conductive surface As shown in Fig. 1, as a suitable example of the resin substrate having a conductive surface, a sheet-like or flexible film-like resin substrate 20 and the resin substrate are provided. A laminate structure including a conductive film 22 formed on the surface of 20 is exemplified.
[0027]
Examples of the resin substrate 20 include tetraacetyl cellulose, polyethylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, syndioctaic polystyrene, polyphenylene sulfide, polycarbonate, polyarylate, and polysulfone. , Polyester sulfone, polyether imide, cyclic polyolefin and the like. The thickness of the resin substrate 20 is not particularly limited, but is usually 0.05 to 5 mm. The resin substrate 20 can be transparent or opaque. Examples of the conductive film 22 include a conductive metal oxide thin film of indium oxide and tin oxide, a metal thin film of gold, silver, platinum, and the like, a conductive polymer, and the like. These may be usually formed on the surface of the resin substrate 20 by a vapor phase film forming method such as sputtering or a liquid phase plating method. In the above example, the structure in which the conductive film 22 is laminated on the resin substrate 20 in order to impart conductivity is illustrated. However, the resin substrate 20 itself is made of a conductive polymer, or the conductive fine particles in the resin. May be dispersed to impart conductivity. In such a case, in particular, the conductive film 22 shown in FIG.
[0028]
Configuration of oxide semiconductor film 4 To form the oxide semiconductor film 4 in the oxide semiconductor electrode 10 of the present invention, first, a coating liquid containing oxide semiconductor fine particles is prepared. The oxide semiconductor fine particles used preferably have a smaller primary particle diameter, and the primary particle diameter is usually 1 to 5000 nm, preferably 5 to 50 nm.
[0029]
Examples of the oxide semiconductor fine particles include titanium oxide, zinc oxide, tin oxide, niobium oxide, indium oxide, zirconium oxide, tantalum oxide, vanadium oxide, yttrium oxide, aluminum oxide, and magnesium oxide. Titanium oxide, zinc oxide, tin oxide and niobium oxide are preferable, and titanium oxide is most preferable. These oxide semiconductor fine particles may be used in combination (mixed, mixed crystal, solid solution, etc.). For example, combinations of zinc oxide and tin oxide, titanium oxide and niobium oxide, and the like can be exemplified. When selecting the material, electron injection from the excitation level of the organic dye (organic dye film 7) adsorbed on the surface of the oxide semiconductor film 4 to the conduction band level of the oxide semiconductor fine particles can occur efficiently. What is necessary is just to select the kind of oxide semiconductor fine particle.
[0030]
In addition, an oxide semiconductor fine particle precursor may be added to enhance the bondability between the oxide semiconductor particles and the bondability between the oxide semiconductor fine particles and the conductive surface (conductive film 22) of the resin substrate 20. This is a preferred embodiment.
[0031]
Coexistence of the oxide semiconductor fine particle precursor is effective for diffusion and supply of substances and reduction of energy required for bonding between fine particles, and is preferable for forming an oxide semiconductor film at a lower temperature.
[0032]
When the oxide semiconductor fine particle is a metal oxide, examples of the oxide semiconductor fine particle precursor that can be used include a metal alkoxide, a metal halide, and a metal compound having a hydrolyzable group.
[0033]
When a metal halide is used, halogen atoms are often taken into the oxide semiconductor fine particles, which may adversely affect battery characteristics. Therefore, it is preferable to use a metal alkoxide especially when high temperature heating cannot be applied.
[0034]
Moreover, what hydrolyzed a part or all of said metal compound, the thing which polymerized the hydrolyzate, or those mixtures are also effective as a precursor. In particular, a mixture obtained by partially hydrolyzing a metal alkoxide under an acid or alkaline condition and further partially polymerizing is rich in reactivity at low temperature, and crystallization at low temperature is likely to occur. Convenient to use. In this case, preferred acids include hydrochloric acid, nitric acid and the like, but nitric acid is preferably used in consideration of the influence of the residual halogen. Examples of the alkali include ammonia and tetraalkylammonium hydroxide.
[0035]
The mixing ratio (addition amount) of the oxide semiconductor fine particle precursor that can be added is 2 to 40 wt% with respect to the oxide semiconductor fine particles. If it is less than 2 wt%, the added effect hardly appears. In addition, volume shrinkage occurs in the process in which the oxide semiconductor fine particle precursor is granulated and crystallized. Therefore, when a large amount of addition exceeds 40 wt%, the volume shrinkage of the entire film increases, cracks are generated, and the film is peeled off from the conductive surface, which may deteriorate the battery characteristics.
[0036]
The coating liquid containing oxide semiconductor fine particles can be obtained in the form of a sol or a slurry. In such a form, examples of the solvent to be used include water, an organic solvent, a mixed solution of water and an organic solvent, and the like. Examples of the organic solvent include alcohols such as methanol, ethanol, propanol and terpineol, ketones such as methyl ethyl ketone, acetone and acetylacetone, and basic solvents such as dimethylformamide and pyridine. In order to improve the dispersibility of the oxide semiconductor fine particles in the solvent, it is preferable to add an acid or an alkali so that the pH of the coating solution is as far as possible from the pH near the isoelectric point of the oxide semiconductor fine particles. Examples of the acid suitably used in this case include mineral acids such as hydrochloric acid, sulfuric acid and nitric acid, and organic acids such as formic acid, acetic acid and benzenesulfonic acid. Suitable alkali components include alkali metals such as sodium hydroxide, potassium hydroxide and calcium carbonate or alkaline earth metal bases, and ammonium bases such as ammonia and tetraalkylammonium hydroxide. In addition, a surfactant and a viscosity modifier can be added to the coating solution as necessary.
[0037]
The coating liquid prepared in this manner is applied onto the resin substrate 20 (the resin substrate 20 having a conductive surface) having conductivity on the surface, and after a predetermined treatment, the oxide semiconductor film 4 Is configured.
[0038]
The oxide semiconductor film 4 in the present invention is preferably a porous film quality. The thickness is at least 10 nm or more, preferably 500 to 30000 nm. Further, it is desirable that the ratio of the actual surface area to the apparent surface area of the oxide semiconductor film 4 is 10 or more, preferably 100 or more. The upper limit of this ratio is not particularly restricted, but is usually 1000 to 2000.
[0039]
The apparent surface area mentioned above means a normal surface area. For example, when the surface shape is a rectangle, it is represented by (vertical length) × (horizontal length). The above-mentioned actual surface area means the BET surface area obtained from the amount of krypton gas adsorbed. For specific measurement, using a BET surface area measuring device (ASAP2000, manufactured by Micromeritics), krypton gas was applied to an oxide semiconductor film (formed on a substrate) having an apparent surface area of 1 cm ² at a liquid nitrogen temperature. A method of adsorption is used. The BET surface area is calculated based on the krypton gas adsorption amount obtained by this measurement method.
[0040]
Such a porous structure film has fine pores inside and fine irregularities on the surface thereof. When the ratio of the actual surface area to the thickness and the apparent surface area of the oxide semiconductor film 4 is smaller than the above range, the surface area of the organic dye monomolecular film is reduced when the organic dye is adsorbed on the surface as a monomolecular film. Therefore, it is difficult to obtain an electrode with good light absorption efficiency.
[0041]
In the present invention, in order to form an oxide semiconductor film on a resin substrate having a conductive surface, a coating solution containing oxide semiconductor fine particles is applied by a spray method. This is because an ideal porous body can be formed without high-temperature treatment as will be described later. At this time, an organic binder component should not be contained in the coating liquid containing oxide semiconductor fine particles. This is because high-temperature heat treatment cannot be performed and the ratio of contribution to the formation of the porous structure is low, and the remaining organic binder component tends to promote deterioration of characteristics.
[0042]
As described above, the formation of the oxide semiconductor film by the spray method is most preferable for realizing the porous oxide semiconductor fine particle film. By partially or entirely volatilizing the solvent contained in the coating solution before the coating solution sprayed from the nozzle reaches the surface of the substrate, the growth of the oxide semiconductor fine particles from primary particles to multi-particles, etc. The resulting film formed on the substrate surface becomes a sponge-like porous film. In this case, the volatility of the solvent of the coating solution is important. Therefore, as the solvent, an alcohol having a relatively low boiling point such as methanol, ethanol or propanol is preferably used.
[0043]
Furthermore, for the purpose of improving the coatability on the substrate surface and adjusting the surface tension and the degree of particle growth of the oxide semiconductor fine particles, a high-boiling solvent such as dimethylformamide or terpineol or water is used in the coating solution. Etc. are also preferably added.
[0044]
In addition, for the purpose of controlling the volatility of the solvent of the coating solution, it is also possible to perform coating while heating the resin substrate 20 itself that is the target of spray coating. Although the heating temperature in this case depends on the heat resistant temperature of the resin substrate to be used, it is preferably carried out at a temperature of 60 ° C. or higher and 300 ° C. or lower, more preferably 80 ° C. or higher and 150 ° C. or lower.
[0045]
The oxide semiconductor fine particle concentration in the coating solution is preferably a low concentration of 2 to 10% by weight in consideration of evaporation of the solvent in spray coating. If the amount is less than 2% by weight, the coating amount per unit time is small, so that the coating time is long. If the amount exceeds 10% by weight, the oxide semiconductor fine particles grow too much and the particle size becomes larger than necessary. There is a possibility that the strength of the film may be weakened due to a decrease in bonding points between the particles.
[0046]
In the case where oxide semiconductor fine particles are used as a constituent element of a photoelectric conversion element, the function as an oxide semiconductor film has been developed by “sintering”. That is, after coating a coating liquid containing oxide semiconductor fine particles on a substrate having a conductive surface, for example, by heating at a high temperature of 400 ° C. or higher, the connectivity between oxide semiconductor particles and the oxide By improving the bonding between the semiconductor fine particles and the conductive surface, the conductivity is improved and the battery characteristics are improved. Further, the oxide semiconductor film 4 is made more porous by decomposing and evaporating the organic binder component existing on the surface of the oxide semiconductor fine particles and between the fine particles, and the filling of the charge transfer layer 5 such as the electrolyte is promoted. As a result, the battery characteristics were improved.
[0047]
However, when a resin substrate is used as in the present invention, the high-temperature firing cannot be performed. Therefore, when the firing temperature is low and the organic binder component is not sufficiently decomposed, it may remain as carbon in the oxide semiconductor fine particle film, and this residual carbon causes leakage current. Battery characteristics are deteriorated.
[0048]
In the present invention, the oxide semiconductor fine particle sol or slurry to be sprayed contains no organic binder component, and the oxide semiconductor film 4 is formed using the oxide semiconductor fine particle sol or slurry. No high temperature heat treatment is required to form. However, in order to further improve the bondability between the oxide semiconductor particles and the bondability between the oxide semiconductor particles and the conductive surface, it is preferable to perform a certain amount of heat treatment, and the oxide formed by the spray coating method described above. The semiconductor film is preferably heat-treated at a temperature of 60 ° C. or higher, particularly in the range of 60 to 300 ° C., more preferably in the range of 80 to 150 ° C. If a heat resistant resin is used, processing at a higher temperature within the above temperature range becomes possible.
[0049]
In addition to such heat treatment, the bonding property can also be improved by irradiating ultraviolet light having a wavelength of 400 nm or less that the oxide semiconductor fine particles absorb. In this case, it is preferable that the integrated light quantity of the irradiated ultraviolet light is 100 J / cm ² or less. When irradiation with an integrated light quantity exceeding 100 J / cm ² is performed, there is a tendency to increase damage to the resin substrate. Moreover, you may perform the process which combined the said heat processing and the ultraviolet light irradiation process. Either may be the first order of processing. You may do it at the same time.
[0050]
In general, the coating liquid (oxide semiconductor fine particle sol or slurry) containing oxide semiconductor fine particles is added with an acid or alkali for the purpose of improving the dispersibility of the fine particles, or the oxide semiconductor fine particle precursor. The origin acid and alkali are mixed, and the possibility that such an acid or alkali partially remains in the oxide semiconductor film 4 is considered.
[0051]
When acid remains in the oxide semiconductor film 4, the open-circuit voltage tends to decrease as battery characteristics due to a decrease in the conduction band level of the oxide semiconductor fine particles. Further, when alkali remains in the oxide semiconductor film 4, there is a tendency that the adsorptivity of the organic dye to the surface of the oxide semiconductor fine particles tends to be reduced, so that the short-circuit current is reduced as battery characteristics. Tend.
[0052]
In the present invention, such an oxide semiconductor film 4 is treated with a neutralizing solution at a stage before the organic dye is adsorbed.
[0053]
That is, (1) when acid remains in the oxide semiconductor film 4, the oxide semiconductor film 4 is immersed in a treatment solution containing an alkali in order to remove the acid remaining in the oxide semiconductor film 4. And the process which neutralizes inside a film | membrane is performed. Thereafter, the neutralized oxide semiconductor film 4 is preferably washed with a solvent such as water or alcohol. By such treatment, the acid component remaining in the oxide semiconductor film 4 is substantially removed.
[0054]
Whether or not the acid component has been substantially removed may be determined using an analytical technique such as quantification of ion species by Raman spectrum, or quantification of constituent elements of ion species by fluorescent X-rays.
[0055]
Examples of the alkali component used herein include alkali metals or alkaline earth metal bases such as sodium hydroxide, potassium hydroxide and calcium carbonate, and ammonium bases such as ammonia and tetraalkylammonium hydroxide. The alkali concentration of the solution containing the alkali is sufficient if it is necessary and sufficient for the neutralization reaction inside the film, and excessive alkali may be taken into the film and adversely affected. Therefore, it is preferable to use a solution in which a weak alkali such as ammonia is mixed with an alcohol such as methanol or ethanol to suppress the dissociation degree as an alkali.
[0056]
(2) On the contrary, when alkali remains in the oxide semiconductor film 4, the oxide semiconductor is added to the treatment solution containing acid in order to remove the alkali remaining in the oxide semiconductor film 4. A treatment for immersing the membrane 4 and neutralizing the inside of the membrane is performed. Thereafter, the neutralized oxide semiconductor film 4 is preferably washed with a solvent such as water or alcohol. By such treatment, the alkali component remaining in the oxide semiconductor film 4 is substantially removed.
[0057]
Whether or not the alkali component has been substantially removed may be determined by using an analytical method such as quantification of ion species by Raman spectrum and quantification of constituent elements of ion species by fluorescent X-rays.
[0058]
Examples of the acid used here include mineral acids such as hydrochloric acid, sulfuric acid and nitric acid, and organic acids such as formic acid, acetic acid and benzenesulfonic acid. The acid concentration of the acid-containing solution may be an amount necessary and sufficient for the neutralization reaction inside the membrane. Conversely, excess acid is taken into the membrane and adversely affects it. Therefore, it is preferable to use a solution in which a weak acid such as acetic acid is mixed with an alcohol such as methanol or ethanol to suppress the degree of dissociation as an acid.
[0059]
The step of immersing the oxide semiconductor film 4 in a solution containing an acid or an alkali may be performed in combination with the heat treatment of the oxide semiconductor film 4 and the ultraviolet light irradiation treatment, and the order of the treatment is not particularly limited. . Further, the heat treatment of the oxide semiconductor film 4 and the step of immersing in a solution containing an acid or an alkali may be performed at the same time.
[0060]
Configuration of organic dye film 7 Next, the organic dye is adsorbed as a single molecule on the surface of the oxide semiconductor film 4 on the substrate thus obtained. As the organic dye, a dye that can be chemically bonded to the oxide semiconductor film 4 is preferable, and one having a carboxyl group, a sulfonic acid group, a phosphoric acid group, or a hydroxyl group in the molecule is preferable.
[0061]
Specifically, bipyridyl Ru complex, tert-pyridyl Ru complex, phenanthroline Ru complex, Ru complex such as bicinchoninic acid Ru complex, phthalocyanine Ru complex, eosin Y, dibromofluorescein, fluorescein, rhodamine B, pyrogallol, dichloro Organic dyes such as fluorescein, erythrosine B, fluorescin, marchrochrome, cyanine, merocyanine and the like can be mentioned.
[0062]
In order to adsorb the organic dye as a single molecule on the surface of the oxide semiconductor film 4, the oxide semiconductor film 4 may be immersed together with the substrate in an organic dye solution formed by dissolving the organic dye in an organic solvent. . In this case, the oxide semiconductor film 4 may be subjected to a reduced pressure treatment before being immersed in the organic dye so that the organic dye solution can enter deep inside the oxide semiconductor film 4 which is a porous structure film. It is preferable to remove the bubbles contained in the oxide semiconductor film 4 in advance by heat treatment. The immersion time may be about 30 minutes to 24 hours. In order to efficiently adsorb the organic dye, a reflux treatment may be performed. Further, the immersion treatment can be repeated a plurality of times as necessary. After performing such an immersion treatment, the oxide semiconductor film 4 having adsorbed the organic dye is usually dried under a temperature condition of room temperature to 80 ° C.
[0063]
In the present invention, the organic dye adsorbed on the oxide semiconductor film 4 does not have to be one kind, and a plurality of organic dyes having different light absorption regions can be adsorbed as necessary. As a result, light can be used efficiently. In order to adsorb a plurality of organic dyes to the film, a method of immersing the oxide semiconductor film 4 in a solution containing a plurality of organic dyes or a plurality of types of organic dye solutions are prepared, and the oxide semiconductor film is added to these solutions. And a method of sequentially immersing 4 and the like.
[0064]
In the solution in which the organic dye is dissolved in the organic solvent, any organic solvent can be used as long as it can dissolve the organic dye. Examples of such a solvent include methanol, ethanol, acetonitrile, dimethylformamide, dioxane, dichloromethane, toluene and the like. The concentration of the organic dye in the solution is about 1 to 200 mg, preferably about 10 to 100 mg, in 100 ml of the solution.
[0065]
The dye-sensitized solar cell 1 of the present invention includes a photoelectric conversion oxide semiconductor electrode 10 having a dye adsorbed on its surface as described above, a counter electrode 30 that forms a pair with the electrode, and charge transfer that contacts these electrodes. Layer 5.
[0066]
Configuration of charge transfer layer 5 The charge transfer layer 5 is a layer containing a charge transport material having a function of replenishing electrons to the oxidant of the dye. Examples of typical charge transport materials that can be used in the present invention include (i) a material that conducts ion transport, that is, a solution in which redox pair ions are dissolved (electrolyte), and a redox pair solution. Examples include so-called gel electrolytes impregnated in a matrix gel, molten salt electrolytes containing redox counterions, and solid electrolytes. In addition to such a charge transport material involving ions, (ii) a material in which carrier movement in a solid is involved in electrical conduction, that is, an electron transport material or a hole transport material can also be used. These can be used in combination.
[0067]
When an electrolytic solution is used for the charge transfer layer 5, the electrolytic solution is preferably composed of an electrolyte, a solvent, and an additive. As an electrolyte, a combination of I ₂ and iodide (as iodide, metal iodide such as LiI, NaI, KI, CsI, CaI ₂ , quaternary ammonium such as tetraalkylammonium iodide, pyridinium iodide, imidazolium iodide, etc.) Compound iodine salt, etc., Br ₂ and bromide combinations (bromide metal bromide such as LiBr, NaBr, KBr, CsBr, CaBr ₂ , bromide salt of quaternary ammonium compound such as tetraalkylammonium bromide, pyridinium bromide, etc.) , Metal complexes such as ferrocyanate-ferricyanate, ferrocene-ferricinium ion, cobalt (II) -bis [2,6-bis (1′-butylbenzimidazol-2′-yl) pyridine] , Sodium polysulfide, alkylthiol-alkyl Sulfur compounds such as sulfides, viologen dye, hydroquinone - quinone or the like can be used. Among these electrolytes, electrolytes in which I ₂ and LiI, I ₂ and iodine salts of quaternary ammonium compounds such as pyridinium iodide and imidazolium iodide are combined are preferable. Note that the electrolytes described above may be used in combination. A preferable electrolyte concentration is 0.1 M or more and 15 M or less, and more preferably 0.2 M or more and 10 M or less. Further, when iodine is added to the electrolyte, a preferable concentration of iodine is 0.01M or more and 0.5M or less.
[0068]
The solvent used for the electrolyte is preferably a compound having a low viscosity and improving the ion mobility, or having a high dielectric constant and an effective carrier concentration, so that excellent ion conductivity can be expressed.
[0069]
Such solvents include carbonate compounds such as ethylene carbonate and propylene carbonate, heterocyclic compounds such as 3-methyl-2-oxazolidinone, ether compounds such as dioxane and diethyl ether, ethylene glycol dialkyl ether, propylene glycol dialkyl ether, polyethylene Chain ethers such as glycol dialkyl ether and polypropylene glycol dialkyl ether, alcohols such as methanol, ethanol, ethylene glycol monoalkyl ether, propylene glycol monoalkyl ether, polyethylene glycol monoalkyl ether, polypropylene glycol monoalkyl ether, ethylene glycol, Propylene glycol, polyethylene glycol, polypropylene Polyhydric alcohols such as glycol and glycerol, acetonitrile, glutarodinitrile, methoxyacetonitrile, propionitrile, nitrile compounds such as benzonitrile, aprotic polar substances such as dimethyl sulfoxide and sulfolane, water, etc. can be used . In addition, basic compounds such as tert-butylpyridine, 2-picoline, and 2,6-lutidine can be added. A preferable concentration range when adding the basic compound is 0.05M or more and 2M or less.
[0070]
The molten salt electrolyte is particularly preferable from the viewpoint of achieving both photoelectric conversion efficiency and durability. Examples of the molten salt electrolyte include pyridinium salts, imidazolium salts, and triazolium described in WO95 / 18456, JP-A-8-259543, Electrochemistry, Vol. 65, No. 11, 923 (1997), and the like. Mention may be made of electrolytes containing known iodine salts such as salts. These molten salts may be used singly or as a mixture of two or more, and may be used in combination with a molten salt in which the iodine anion is replaced with another anion.
[0071]
Examples of anions that can be replaced with iodine anions include halide ions (Cl ⁻ , Br ⁻ etc.), NSC ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ Preferred examples include CF ₂ SO ₂ ) ₂ N ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ COO ⁻ , Ph ₄ B ⁻ , (CF ₃ SO ₂ ) ₃ C ^{− and the} like. Also, other iodine salts such as LiI can be added.
[0072]
The molten salt electrolyte is preferably in a molten state at room temperature, and preferably does not use a solvent. Although the solvent as described above may be added, the content of the molten salt is preferably 50% by mass or more, particularly preferably 90% by mass or more, based on the entire electrolyte composition. Moreover, it is preferable that 50 mass% or more is an iodine salt among salts. It is preferable to add iodine to the electrolyte composition. In this case, the content of iodine is preferably 0.1 to 20% by mass, and 0.5 to 5% by mass with respect to the entire electrolyte composition. Is more preferable.
[0073]
The electrolyte can be used after gelation (solidification) by a technique such as addition of a polymer, addition of an oil gelling agent, polymerization including polyfunctional monomers, or a crosslinking reaction of the polymer. In the case of gelation by adding a polymer, polyacrylonitrile, polyvinylidene fluoride, or the like can be preferably used. A preferred compound in the case of gelation by adding an oil gelling agent is a compound having an amide structure in the molecular structure. Further, when the electrolyte is gelled by a polymer crosslinking reaction, it is desirable to use a polymer containing a crosslinkable reactive group and a crosslinking agent in combination. In this case, a preferable crosslinkable reactive group is a nitrogen-containing heterocyclic ring (for example, a pyridine ring, an imidazole ring, a thiazole ring, an oxazole ring, a triazole ring, a morpholine ring, a piperidine ring, a piperazine ring), and a preferable crosslinking agent. Is a bifunctional or higher functional reagent (for example, alkyl halide, aralkyl halide, sulfonate ester, acid anhydride, acid chloride, isocyanate, etc.) capable of electrophilic reaction with a nitrogen atom.
[0074]
Further, instead of an ion conductive electrolyte such as a molten salt, a solid hole transport material that is organic or inorganic or a combination of both can be used.
[0075]
As the organic hole transport material applicable to the present invention, aromatic amines and triphenylene derivatives can be preferably used. Oligothiophene compound, polypyrrole, polyacetylene and derivatives thereof, poly (p-phenylene) and derivatives thereof, poly (p-phenylene vinylene) and derivatives thereof, polythienylene vinylene and derivatives thereof, polythiophene and derivatives thereof, polyaniline and derivatives thereof, Conductive polymers such as polytoluidine and its derivatives can be preferably used.
[0076]
A p-type inorganic compound semiconductor can be used as the inorganic hole transport material. The p-type inorganic compound semiconductor for this purpose preferably has a band gap of 2 eV or more, and more preferably 2.5 eV or more. Also, the ionization potential of the p-type inorganic compound semiconductor needs to be smaller than the ionization potential of the dye-adsorbing electrode from the condition that the holes of the dye can be reduced. Although the preferable range of the ionization potential of the p-type inorganic compound semiconductor varies depending on the dye used, it is generally preferably 4.5 eV or more and 5.5 eV or less, and more preferably 4.7 eV or more and 5.3 eV or less. .
[0077]
A preferred p-type inorganic compound semiconductor is a compound semiconductor containing monovalent copper. Specifically, examples of the compound semiconductor containing monovalent copper are _{CuI, CuSCN, CuInSe 2, Cu} (In, Ga) Se 2, CuGaSe 2, Cu 2 O, CuS, etc. CuGaS _2, CuInS _2, CuAlSe ₂ Is mentioned. As other p-type inorganic compound semiconductors, GaP, NiO, CoO, FeO, Bi ₂ O ₃ , MoO ₂ , Cr ₂ O _{3 and the} like can be used.
[0078]
Regarding the method for forming the charge transfer layer, for example, the following two methods may be used. One is a method in which the photoelectric conversion oxide semiconductor electrode 10 and the counter electrode 30 are bonded together, and the liquid charge transfer layer 5 is sandwiched between the gaps. The other is a method in which the charge transfer layer 5 is provided directly on the photoelectric conversion oxide semiconductor electrode 10, and the counter electrode 30 is formed and applied thereafter.
[0079]
In the former case, as a method for sandwiching the charge transfer layer 5, a normal pressure process using capillary action by dipping, injection or the like, or a vacuum process in which the gas phase in the gap is replaced with a liquid phase by lowering the pressure to normal pressure can be used. . The whole of the photoelectric conversion oxide semiconductor electrode 10, the charge transfer layer 5, and the counter electrode 30 is resin-sealed, or is housed in a case and the whole is resin-sealed.
[0080]
In the latter case, in the wet charge transfer layer 5, the counter electrode 30 is applied without being dried, and measures for preventing liquid leakage at the edge portion are performed. In the case of a gel electrolyte, there is a method in which it is applied in a wet manner and solidified by a method such as polymerization. In this case, the counter electrode can be applied after drying and fixing.
[0081]
In the case of a solid electrolyte or a solid hole transport material, the charge transfer layer 5 is formed using a dry film forming method such as a vacuum deposition method or a CVD method, and then the counter electrode 30 is applied. it can.
[0082]
The organic hole transport material can be introduced into the electrode by a technique such as vacuum deposition, casting, coating, spin coating, dipping, electrolytic polymerization, or photoelectrolytic polymerization. Also in the case of an inorganic solid compound, it can be introduced into the electrode by techniques such as casting, coating, spin coating, dipping, and electrolytic plating.
[0083]
Configuration of counter electrode 30 The counter electrode 30 may have a single-layer structure of a counter electrode conductive layer made of a conductive material, or a combination structure of a counter electrode conductive layer and a support substrate. As a conductive material used for the counter electrode conductive layer, metal (for example, platinum, gold, silver, copper, rhodium, ruthenium, aluminum, magnesium, indium, etc.), carbon, or conductive metal oxide (indium-tin composite oxide, fluorine Doped tin oxide, etc.). As a preferable support substrate for the counter electrode, glass or plastic can be exemplified, and a conductive agent is applied or vapor-deposited thereon to form the conductive layer.
[0084]
Since light may be irradiated from either or both of the oxide semiconductor electrode 10 for photoelectric conversion and the counter electrode 30, in order for light to reach the organic dye layer, the oxide semiconductor electrode 10 for photoelectric conversion and the counter electrode 30 It is sufficient that at least one of them is substantially transparent. A battery having such a structure has a potential difference between the photoelectric conversion oxide semiconductor electrode 10 and the counter electrode 30 when the photoelectric conversion oxide semiconductor electrode 10 is exposed to sunlight or visible light equivalent to sunlight. And acts so that a current flows between the poles 10 and 30.
[0085]
【Example】
Next, the present invention will be described in more detail with reference to specific examples of the present invention.
[0086]
[Example 1]
Preparation of titanium oxide sol liquid A titanium oxide sol liquid was prepared by hydrolyzing titanium isopropoxide as follows.
[0087]
125 ml of titanium isopropoxide was added to 750 ml of 0.1 M aqueous nitric acid solution with stirring. This was vigorously stirred at 80 ° C. for 8 hours. The resulting liquid was autoclaved at 230 ° C. for 16 hours in a Teflon pressure vessel. The sol solution containing the precipitate was resuspended by stirring. The precipitate that was not resuspended was removed by suction filtration, and the sol solution was concentrated with an evaporator until the titanium oxide concentration became 11 wt%. One drop of Triton X-100 was added to improve the paintability on the substrate.
[0088]
Next, a titanium alkoxide derivative was added to the sol solution as a titanium oxide fine particle precursor in the following manner.
[0089]
While stirring the sol solution in dry nitrogen, an 80:20 mixed solution of di-iso-propoxy bis (acetylacetonato) titanium and methanol was added little by little. After completion of the addition, the mixture was stirred for 1 hour. The addition amount of di-iso-propoxy bis (acetylacetonato) titanium was 6.8 g (20% by weight with respect to the titanium oxide fine particle weight). Furthermore, it diluted with methanol so that the titanium oxide fine particle density | concentration might be 2 weight%, and it was set as the density | concentration suitable for spray coating.
[0090]
Production of oxide semiconductor electrode 10 for photoelectric conversion Using the titanium oxide sol solution prepared as described above, an oxide semiconductor electrode 10 for photoelectric conversion (titanium oxide electrode) was produced in the following manner.
[0091]
A flexible conductive polycarbonate film resin substrate having a length of 2.0 cm, a width of 1.5 cm, and a thickness of 0.1 mm (ITO is sputtered on the surface of the polycarbonate film substrate as a conductive film (thickness 600 nm) The sheet resistance is 30 Ω / □), and a masking tape with a thickness of 70 μm provided with a square hole of 0.5 cm in length and 0.5 cm in width is pasted on the conductive film surface side. A titanium oxide sol solution was sprayed toward the hole. After coating, the masking tape was peeled off and heated at 100 ° C. for 30 minutes using an electric furnace. The temperature rising rate was 2 ° C./min.
[0092]
Next, such an oxide semiconductor film was treated with a neutralization solution. That is, a 2 wt% ammonia water / methanol diluted solution is prepared as an alkaline solution, the oxide semiconductor film is immersed in this solution for 30 minutes, taken out, washed with methanol, and dried at 80 ° C. for 10 minutes. I let you. Thereafter, it was confirmed by Raman spectrum measurement that the acid component (nitrate ion component, 1040 to 1050 cm ⁻¹ ) derived from the titanium oxide sol was completely removed by the alkaline solution immersion treatment. Note that the thickness of the titanium oxide film which is an oxide semiconductor film was about 6 μm.
[0093]
Subsequently, 20 ml of anhydrous ethanol solution in which (4,4′-dicarboxylic acid-2,2′-bipyridine) ruthenium (II) diisothiocyanate was added at a concentration of 3 × 10 ⁻⁴ M as a sensitizing dye was obtained. And soaked for 12 hours.
[0094]
After standing, the titanium oxide electrode was taken out and washed with anhydrous acetonitrile. The titanium oxide film on the substrate became deep red due to the adsorbed ruthenium dye (production of 10 oxide semiconductor electrode samples for photoelectric conversion).
[0095]
Production of dye-sensitized solar cell A dye-sensitized solar cell was produced in the following manner using the above-described oxide semiconductor electrode for photoelectric conversion (titanium oxide electrode).
[0096]
That is, a spacer having a length of 0.5 cm, a width of 0.5 cm, and a width of 1.5 cm, a width of 1.5 cm, and a thickness of 70 μm is formed between the square hole portion and the titanium oxide film portion of the electrode. Were placed on the titanium oxide electrode so as to coincide with each other and closely adhered to the electrode.
[0097]
The electrolyte was placed in the square hole, the counter electrode 30 was placed thereon, and the periphery thereof was sealed with an epoxy resin to produce a battery.
[0098]
As the electrolytic solution, a mixed solution (volume mixing ratio = 80/20) of ethylene carbonate containing tetrapropylammonium iodide (0.4M) and iodine (0.04M) and acetonitrile was used. As the counter electrode, conductive glass in which platinum was deposited with a thickness of 100 nm was used. Using an AM1.5 (1000 W / m ² ) solar simulator, open voltage (Voc), photocurrent density (Jsc), form factor (FF), and conversion efficiency (η) are measured. The battery characteristics were evaluated. The open circuit voltage (Voc) represents the voltage between both terminals when the output terminal of the solar cell module is opened. The photocurrent density (Jsc) represents the current (per 1 cm ² ) flowing between both terminals when the output terminals of the solar cell module are short-circuited. The form factor (FF) is a value obtained by dividing the maximum output Pmax by the product of the open circuit voltage (Voc) and the photocurrent density (Jsc) (FF = Pmax / Voc · Jsc). It is a parameter that represents a characteristic.
These results are shown in Table 1 below.
[0099]
[Comparative Example 1]
In the comparative example 1, the alkaline solution immersion treatment of the oxide semiconductor film performed in the example 1 was not performed. Other than that was carried out similarly to the said Example 1, and produced the titanium oxide electrode and the solar cell, and evaluated the battery. The evaluation results are shown in Table 1 below.
[0100]
[Example 2]
In Example 1, after the titanium oxide sol solution was applied by spraying, the heat treatment performed at 100 ° C. for 30 minutes using an electric furnace was changed to ultraviolet irradiation treatment as shown below. That is, after spray-applying the titanium oxide sol solution in the same manner as in Example 1, the masking tape was peeled off, and ultraviolet light having a wavelength of 400 nm or less (wavelength 220 to 380 nm) and an intensity of 30 mW / cm ² was applied from the titanium oxide film surface side. Irradiation was performed for 15 minutes (accumulated light amount was 27 J / cm ² ). Except for this change, the oxide semiconductor electrode for photoelectric conversion (titanium oxide electrode) of Example 2 and dye enhancement were performed in the same manner as in Example 1 above (including, of course, alkaline solution immersion treatment of the oxide semiconductor film). A sensitive solar cell was produced. Evaluation of the solar cell was performed in the same manner as in Example 1. The evaluation results are shown in Table 1 below.
[0101]
[Comparative Example 2]
In Comparative Example 2, the alkaline solution immersion treatment of the oxide semiconductor film performed in Example 2 was not performed. Other than that was carried out similarly to the said Example 2, and produced the titanium oxide electrode and the solar cell, and evaluated the battery. The evaluation results are shown in Table 1 below.
[0102]
Example 3
The ultraviolet irradiation treatment in Example 2 was added to the heat treatment in Example 1 at 100 ° C. for 30 minutes. That is, after spray-coating a titanium oxide sol solution, heat treatment was performed at 100 ° C. for 30 minutes using an electric furnace, and then, from the titanium oxide film surface side, a wavelength of 400 nm or less (wavelength 220 to 380 nm), an intensity of 30 mW / cm ² was irradiated for 15 minutes (accumulated light amount was 27 J / cm ² ). Except for this change, the oxide semiconductor electrode for photoelectric conversion (titanium oxide electrode) of Example 3 and dye increase were performed in the same manner as in Example 1 above (including, of course, an alkaline solution immersion treatment of the oxide semiconductor film). A sensitive solar cell was produced. Evaluation of the solar cell was performed in the same manner as in Example 1. The evaluation results are shown in Table 1 below.
[0103]
[Comparative Example 3]
In the comparative example 3, the alkaline solution immersion treatment of the oxide semiconductor film performed in the example 3 was not performed. Other than that was carried out similarly to the said Example 3, and produced the titanium oxide electrode and the solar cell, and evaluated the battery. The evaluation results are shown in Table 1 below.
[0104]
[Comparative Example 4]
In Comparative Example 4, the formation of the titanium oxide film was changed from the spray method of Example 1 to the squeegee method. That is, a flexible conductive polycarbonate film resin substrate having a length of 2.0 cm, a width of 1.5 cm, and a thickness of 0.1 mm (ITO is formed as a conductive film on the surface of the polycarbonate film substrate by sputtering (thickness). A sheet resistance of 30 Ω / □), and a masking tape having a thickness of 70 μm and a square hole of 0.5 cm in length and 0.5 cm in width is provided on the conductive film surface side. After the titanium oxide sol solution was added to the end of the square hole with a pipette, the sol solution was spread on a substrate (by a squeegee) by stretching it using a glass plate having a flat edge. The film thus spread was dried in air for 30 minutes, and after drying, the masking tape was peeled off. Next, it heated for 30 minutes at 100 degreeC using the electric furnace. The temperature rising rate was 2 ° C./min.
[0105]
Except for this change, the same procedure as in Example 1 above (of course, including an alkaline solution immersion treatment of the oxide semiconductor film), the oxide semiconductor electrode for photoelectric conversion (titanium oxide electrode) of Comparative Example 4, and dye enhancement A sensitive solar cell was produced. Evaluation of the solar cell was performed in the same manner as in Example 1. The evaluation results are shown in Table 1 below.
[0106]
[Reference Example 1]
In the reference example 1, the titanium oxide sol liquid used in the above Example 1 was made to contain an organic binder component. That is, after adding 6.8 g of polyethylene glycol having a molecular weight of 20000 (20% by weight with respect to the titanium oxide fine particle weight) to the titanium oxide sol solution used in Example 1, methanol concentration is adjusted to 2% by weight. -Diluted with water. Other than that was carried out similarly to the said Example 1, and produced the titanium oxide electrode and the solar cell, and evaluated the battery. The evaluation results are shown in Table 1 below.
[0107]
[Table 1]

[0108]
Comparison results of Example 1 and Comparative Example 1 shown in Table 1, Comparison results of Example 2 and Comparative Example 2, Comparison results of Example 3 and Comparative Example 3, and Example 1 and Comparative Example 4 From the comparison results, it was confirmed that the example samples of the present invention have much higher photoelectric conversion efficiency than the respective comparative example samples.
[0109]
【The invention's effect】
The effects of the present invention are clear from the above results. That is, the present invention is a dye-sensitized solar cell having an oxide semiconductor electrode for photoelectric conversion having a dye formed on the surface, a counter electrode paired therewith, and a charge transfer layer in contact with these electrodes. The oxide semiconductor electrode for photoelectric conversion includes a resin substrate having a conductive surface, an oxide semiconductor film formed on the conductive surface, and an organic dye formed on the oxide semiconductor film. The oxide semiconductor film is formed by spray-coating a sol or slurry of oxide semiconductor fine particles, and the oxide semiconductor film is in a stage before forming an organic dye, Therefore, even if only the low temperature treatment of the oxide semiconductor film is performed using the resin substrate, the energy conversion efficiency is remarkably improved. Further, by using the resin substrate, the battery can be reduced in weight and cost. Furthermore, it is possible to reduce adverse effects on the environment and human body for mass production.
[Brief description of the drawings]
FIG. 1 is a drawing showing an example of a schematic configuration of a dye-sensitized solar cell of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Dye-sensitized solar cell 4 ... Oxide semiconductor film 5 ... Charge transfer layer 7 ... Organic dye film 10 ... Oxide semiconductor electrode 20 for photoelectric conversion ... Substrate 22 ... Transparent conductive layer 30 ... Counter electrode

Claims (6)

An oxide semiconductor electrode for photoelectric conversion, comprising: a resin substrate having a conductive surface; an oxide semiconductor film formed on the conductive surface; and an organic dye film formed on the oxide semiconductor film. ,
The oxide semiconductor film is formed by spraying a sol or slurry of oxide semiconductor fine particles, and the oxide semiconductor film is in contact with the neutralization treatment solution at a stage before forming the organic dye film. An oxide semiconductor electrode for photoelectric conversion, which is treated.   The oxide semiconductor electrode for photoelectric conversion according to claim 1, wherein the neutralization treatment solution contains an acid or an alkali.   3. The oxide semiconductor electrode for photoelectric conversion according to claim 1, wherein an organic binder component is not contained in the sol or slurry of the oxide semiconductor fine particles to be spray-coated. A dye-sensitized solar cell having an oxide semiconductor electrode for photoelectric conversion having a dye formed on its surface, a counter electrode paired therewith, and a charge transfer layer in contact with these electrodes,
The oxide semiconductor electrode for photoelectric conversion has a resin substrate having a conductive surface, an oxide semiconductor film formed on the conductive surface, and an organic dye film formed on the oxide semiconductor film. And
The oxide semiconductor film is formed by spraying a sol or slurry of oxide semiconductor fine particles, and the oxide semiconductor film is in contact with the neutralization treatment solution at a stage before forming the organic dye film. A dye-sensitized solar cell characterized by being treated.   The dye-sensitized solar cell according to claim 4, wherein the neutralization treatment solution contains an acid or an alkali.   The dye-sensitized solar cell according to claim 4 or 5, wherein the sol or slurry of the oxide semiconductor fine particles to be spray-coated does not contain an organic binder component.

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