JP2005285756A - Electrolyte composition, dye-sensitized solar cell, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolyte composition capable of eliminating possibility of leakage of liquid completely, reducing work cost and material cost by simplifying a sealing process and expanding selection of a sealing material, and improving basic photoelectric transfer characteristic. <P>SOLUTION: This electrolyte composition used in a dye-sensitized solar cell for converting light energy into electric energy by carrying coloring matter in a semiconductor and exciting coloring matter by light contains at least aluminum oxide and water and is like paste. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electrolyte composition used for a dye-sensitized solar cell, a dye-sensitized solar cell, and a method for producing the same.

Photoelectric conversion elements using semiconductors such as silicon convert light rays such as sunlight and laser light into electrical energy, and solar cells using these elements also emit CO ₂ as an alternative energy source for petroleum. Not attracting attention as an energy source. The types of photoelectric conversion elements used in solar cells include single crystal silicon type, amorphous silicon type, polycrystalline silicon type, and other compound types, but these have the following problems. That is, since the single crystal silicon type is manufactured by the same process as semiconductor manufacturing, the conversion efficiency is high, but the unit price is high. Further, since the light absorption coefficient is small, a certain thickness is required (preferably 50 μm or more), the amount of expensive high-purity silicon used is increased, and the material cost is increased. On the other hand, even if the production cost is reduced by using polycrystalline silicon, the thickness of the expensive silicon material of the solar cell cannot be reduced, so that the material cost is still high. Under these circumstances, research on amorphous silicon solar cells that can be manufactured in a large area with a low manufacturing cost is underway. However, the raw materials are the same, and it is difficult to say that there is a sufficient cost reduction effect.

  On the other hand, as one form of the photoelectric conversion device, unlike a conventional solar cell, instead of using Si as a raw material, for example, as described in Patent Document 1, a first transparent electrode is provided on the first transparent electrode. Attention has been focused on a device comprising a transparent semiconductor obtained, a color material having a sensitizing effect adsorbed on the surface of the transparent semiconductor, a charge transport layer thereon, and a second transparent electrode on the charge transport layer. Such a device does not require an expensive high-purity Si raw material, and an inexpensive oxide semiconductor such as titanium oxide or zinc oxide is used, so that the raw material cost can be significantly reduced. In addition, unlike Si solar cells, a manufacturing apparatus under high vacuum is not required, and thus a significant cost reduction of manufacturing facilities can be considered, which is considered to be a big step for the spread of solar cells.

  This photoelectric conversion device operates through the following process.

  When the incident light reaches the color material having a sensitizing effect through the first transparent electrode and the transparent semiconductor or reaches the sensitizing color material through the second transparent electrode and the carrier layer, the light has a color having the sensitizing effect. The material is excited, generating electrons at the LUMO level and holes at the HOMO level. The LUMO level electrons of the sensitized color material generated by excitation quickly move to the conduction band of the transparent semiconductor and pass to the first transparent electrode. The holes remaining at the HOMO level of the sensitizing color material receive electrons from the carrier transfer layer, and the sensitizing color material is neutralized. Ions or holes generated in the carrier transport layer by passing electrons are diffused in the carrier transport layer, reach the second transparent electrode, and receive electrons from the second transparent electrode. By using the first transparent electrode that receives electrons as the negative electrode and the second transparent electrode that passes electrons as the positive electrode, the incident light pattern can be obtained as an electrical signal or power.

Japanese Patent No. 2664194

  However, in such a photoelectric conversion element, since a liquid electrolyte is used, its durability is a problem.

  The main deterioration factors found in long-term use are: (1) electrolyte leakage, volatilization (2) short circuit between electrodes (3) dye deterioration (4) peeling of porous electrode (5) deterioration of transparent electrode And so on. Among these, (1) leakage and volatilization of the electrolyte are the biggest problems, and it is very difficult to perform liquid sealing in a form that can withstand long-time light irradiation in a large area even in the manufacturing process.

  In recent years, studies have been vigorously conducted on electrolytes using a solvent having a high boiling point such as polyethylene glycol, and electrolytes using an ionic liquid that is liquid at room temperature and does not volatilize as a main component. In these studies, the electrolyte is hardly volatilized, so it has been announced that it has excellent durability. However, as long as a liquid electrolyte is used, even if it is a minute sealing breakage, a large amount of electrolyte solution due to capillary action It is very difficult to maintain a complete sealing state for a long time in a system using a flexible substrate, and the selection of the sealing material and the completeness of the sealing process are very difficult. Is required at a high level.

  In order to avoid the difficulty of sealing, research on applying solid electrolytes has also been conducted, and research using copper iodide, which is a P-type semiconductor, and conducting polymer organic hole transport layers are also conducted. It has been broken. However, sufficient properties such as inability to maintain characteristics for a long time and low conversion efficiency have not been obtained yet.

  In order to solve these problems, the most promising method at present is gelation of a liquid electrolyte. Chem. commun. 2002, 374, etc., research using low molecular weight gelling agents, chem. lett. 948, 2002 and the like, a method in which a reaction precursor is introduced into a cell and polymerized to construct a matrix and then infiltrated with an electrolyte, chem. lett. 918 (2002) proposes a method of forming a gel of a micro-layer separation structure by using a vinylpyridine polymer and a polyfunctional halide as a cross-linking agent in an electrolytic solution.

  In either case, the performance is equivalent or close to that of a liquid electrolyte, but it is necessary to inject a reaction solution after sealing the cell and promote gelation by heat, etc. More complicated than those using electrolytes.

  Japanese Patent Application Laid-Open No. 2003-226766 discusses a method of forming a porous film with an HFP-PVDF copolymer and impregnating with an electrolytic solution to obtain a film-like electrolyte. It is considered to be very useful as one method for simplifying the handling of the electrolyte. This photoelectric conversion device is considered to be able to significantly reduce the cost by using a plastic film formed with ITO as a transparent conductive film as a medium and performing integrated production by roll-to-roll. However, in order to apply an electrolyte to a predetermined pattern, it is considered necessary to install a molded film-like electrolyte at a predetermined position, or to apply a film to the whole and appropriately remove unnecessary portions. Processes, equipment, alignment methods, etc. are considered necessary.

  In view of the above-mentioned conventional problems, the present invention can apply an electrolyte in the same process as the porous semiconductor manufacturing process in which a paste-like dispersion is applied to a substrate by a method such as screen printing, and compared with a liquid electrolyte. The object is to provide a paste-like electrolyte that does not greatly deteriorate in performance and to simplify the process.

  In order to achieve the above-described object, as a result of intensive studies, by adding alumina oxide fine particles containing water to the electrolytic solution, the electrolyte is made into a highly transparent paste, and the electrolyte is applied by a method such as screen printing. The present invention has been completed by finding that it is possible to achieve the same performance as the photoelectric conversion characteristics before addition, and that the performance can be exceeded depending on the conditions.

  That is, the electrolyte composition of the present invention is an electrolyte composition used for a dye-sensitized solar cell in which a dye is supported on a semiconductor and light energy is converted into electric energy by photoexcitation of the dye, and includes at least aluminum oxide and water. Preferably, it contains 1 to 20 wt% aluminum oxide and 5 to 30 wt% water, and is paste-like.

  The dye-sensitized solar cell of the present invention is characterized by having an electrolyte layer made of the above electrolyte composition.

  Moreover, the method for producing a dye-sensitized solar cell of the present invention includes a step of applying the electrolyte composition to a semiconductor on an electrode to form an electrolyte layer, and a step of providing a counter electrode on the electrolyte layer. It is characterized by that.

  The electrolyte composition of the present invention can eliminate the concern of liquid leakage, and can reduce work costs and material costs by simplifying the sealing process and expanding the selection of sealing materials. Furthermore, the improvement of basic photoelectric conversion characteristics is also seen, which is very effective.

  Details of the present invention will be described below.

  FIG. 1 is a schematic cross-sectional view showing an example of the dye-sensitized solar cell of the present invention. The dye-sensitized solar cell shown in FIG. 1 has an electrolyte layer 4 sandwiched between a semiconductor electrode substrate 10 and a counter substrate 11. The semiconductor electrode substrate 10 is formed by forming a semiconductor electrode 3 carrying a dye on a conductive substrate in which a conductive layer 2 is formed on a base 1. The counter substrate 11 forms a counter electrode 5 on a base 6. Do it. The conductive layer 2 and the counter electrode 5 are not necessarily provided when the substrate 1 and the substrate 6 are conductive. From the viewpoint of photoelectric conversion efficiency, it is preferable that either the conductive substrate or the counter substrate 11 be non-transparent, but both may be transparent depending on the application.

<Electrolyte layer 4>
The electrolyte layer is made of a paste-like electrolyte composition containing aluminum oxide and water. The electrolyte composition of the present invention is, for example, that a paste obtained by dispersing aluminum oxide (alumina) with water is added to an electrolytic solution, and the whole electrolyte is processed into a paste by mixing. Can be obtained.

  The content of aluminum oxide is preferably 1 to 20 wt%, more preferably 5 to 15 wt%. If the aluminum oxide is less than 1 wt%, it may be difficult to form a paste. If the aluminum oxide exceeds 20 wt%, the relative amount of the electrolyte is reduced, which may reduce the conversion efficiency. The water content is preferably 5 to 30 wt%, more preferably 10 to 20 wt%. If the water content is less than 5 wt%, the uniformity of the paste is lost, and there is a possibility that the paste does not become a paste that can be applied. If the water content exceeds 20 wt%, phenomena such as electrolyte outflow and reduced conversion efficiency may occur.

  In the present invention, after the liquid is filled in the cell by combining the semiconductor electrode and the counter electrode, it is distinguished from “gelation” in which the fluidity is lost by light or heat. The state reduced by the product is described as “paste-like”, and such an electrolyte composition is described as “paste-like electrolyte composition”. In the present invention, the aluminum oxide includes alumina hydrate and alumina hydroxide.

  As an aluminum oxide, what is called a Bayer method and what was manufactured by baking the aluminum hydroxide obtained by carrying out the hot caustic soda processing of the bauxite which is a natural mineral can be used. In addition to this, those produced by spark discharge of metal aluminum pellets in water and then calcining the obtained aluminum hydroxide, methods of decomposing inorganic aluminum salts (alum etc.), etc. can be used.

  As for the crystal structure of aluminum oxide, it is known that the transition from kibsite-type and boehmite-type aluminum hydroxide to γ, σ, η, θ, α-type aluminum oxides depends on the heat treatment temperature. Yes. Of course, any of these crystal structures can be used in the present invention. Among these, γ-type crystal type aluminum oxide is preferable in terms of ink absorbability and transparency of the formed electrolyte layer.

  As the aluminum oxide, alumina hydrate represented by the following composition formula can be used.

Al ₂ O _3-n (OH) _2n · mH ₂ O
(In the formula, n represents an integer of 1, 2 or 3, and m represents a value of 0 to 10, preferably 0 to 5.)
Since mH ₂ O often represents a detachable aqueous phase that does not participate in the formation of a crystal lattice, m can take an integer or a non-integer value. Also, when this type of material is heated, m can reach a value of zero.

  Alumina hydrate is generally used for hydrolysis of aluminum alkoxide and sodium aluminate as described in U.S. Pat. No. 4,242,271 and U.S. Pat. No. 4,420,870. It can be produced by a known method such as a method in which an aqueous solution of aluminum sulfate, aluminum chloride or the like is added to an aqueous solution of sodium aluminate or the like described in JP-A-57-44605. As an alumina hydrate, it can select from what was manufactured by these methods, and commercial items, such as Disperal (brand name: product made from SASOL).

The aluminum oxide preferably has an average particle size of 1 μm or less, more preferably 50 nm or more and less than 500 nm. When the average particle diameter exceeds 1 μm, the transparency of the electrolyte composition tends to decrease. Further, the BET specific surface area is preferably 100 m ² / g or more. If it is less than 100 m ² / g, the electrolyte composition may become cloudy due to light scattering.

  Next, as the electrolytic solution, those mainly composed of an ionic liquid are preferable.

Examples of the ionic liquid include, but are not limited to, imidazolium salts, pyridinium salts, pyrazolium salts, triazolium salts, and the like. Moreover, these can be used individually or in mixture of 2 or more types. The ionic liquid is preferably a liquid at room temperature. In particular, imidazolium salts such as 1-methyl-3-ethylimidazolium salt and 1-methyl-3-propylimidazolium salt are preferably used. The counter anion of the ionic liquid is preferably an iodine ion used as a redox pair. However, in order to adjust the solubility, viscosity and other properties, halogen ions such as Cl ⁻ and Br ⁻ , NSC ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ CF ₂ SO ₂ ) ₂ N ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ COO ⁻ , Ph ₄ B ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , F (HF) _n or the like or a mixture thereof may be used.

  As the electrolyte composition, in addition to the ionic liquid, or in place of the ionic liquid, a solvent that hardly volatilizes, a liquid having a high boiling point and no vapor pressure, or a very small liquid can be used. It is more preferable to use an organic solvent. Furthermore, when the vapor pressure of the organic solvent contained is 1 mmHg or less at 20 ° C., the volatilization prevention effect is further enhanced, which is preferable. Although the example of the organic solvent which can be used is shown next, it is not limited to this.

  An electrolyte composition containing a large amount of an organic solvent has a small tack when made into a paste and is very easy to handle when used in a coating process. Moreover, since the viscosity is lower than that of an ionic liquid, it is one of the reasons that it is preferably used because it easily penetrates into a semiconductor.

  In addition, an organic solvent can be contained for the purpose of adjusting the viscosity. Preferably, the viscosity is low in order to increase ion mobility, and the dielectric constant is high in order to increase the effective carrier concentration. For example, carbonates, lactones, ethers, alcohols, glycols, tetrahydrofurans, nitriles, carboxylic acid esters, phosphoric acid triesters, N-methylpyrrolidone, 2-methyl-1,3-dioxolane, sulfolane Or aprotic organic solvents such as dimethyl sulfoxide, formamide, N, N-dimethylformamide, nitromethane, etc., or a mixture thereof.

As the redox _couple of the electrolyte composition, those containing I ⁻ and I ₃ ⁻ obtained by mixing iodine molecules (I ₂ ) with, for example, alkali metal iodides and iodine salts of organic cations are preferably used. It is done.

  Examples of iodides include, for example, iodides of alkali metals or alkaline earth metals (Li, Na, K, Mg, etc.), quaternary ammonium compounds such as tetraalkylammonium iodide salts, pyridinium iodide salts, imidazolium iodide salts, An iodide of a heterocyclic nitrogen-containing compound can be used. Specific examples include 1,3-dimethylimidazolium iodide, 1-methyl-3-ethylimidazolium iodide, 1-methyl-3-propylimidazolium iodide, 1-methyl-3-hexylimidazolium iodide. Examples include iodide, 1,2-dimethyl-3-propylimidazole iodide, 1-ethyl-3-isopropylimidazolium iodide, pyrrolidinium iodide, and the like, one or two selected from these More than seeds can be used.

Further, the concentration of the electrolyte salt is preferably 0.05M to 5M, more preferably 0.2M to 1M with respect to the solvent or ionic liquid. The concentration of I ₂ or Br ₂ is preferably 0.0005M to 1M, more preferably 0.001M to 0.1M. Various additives such as 4-tert-butylpyridine and carboxylic acid can be added for the purpose of improving the open circuit voltage and the short circuit current.

  The ionic conductivity improves as the proportion of the electrolyte component in the electrolyte composition increases, but the paste properties become closer to liquid. Therefore, the ratio of the electrolytic solution component in the electrolyte composition is preferably 50 wt% or more, and more preferably 70 wt% to 90 wt%.

<Semiconductor electrode substrate 10>
The semiconductor electrode substrate can be formed as follows, for example.

  First, semiconductor fine particles such as titanium oxide fine particles, a film forming additive such as a dispersant and a thickener, and a solvent are mixed and dispersed using a dispersing device such as a sand mill to prepare a semiconductor fine particle dispersion. As the solvent and the dispersant, those suitable for film formation can be appropriately selected. For example, a mixture of water and acetylacetone can be preferably used. The thickener is intended to improve the uniformity of the film by increasing the viscosity of the semiconductor fine particle dispersion and to prevent peeling and cracking when the semiconductor electrode is fired. Those that completely evaporate at a lower temperature are preferably used. For example, when the electrode is baked at 500 ° C., a cellulose binder such as hydroxypropyl cellulose having a boiling point of 500 ° C. or less, polyethylene glycol having a molecular weight of about 10,000 to 20,000, and the like can be suitably used. The addition amount of various additives is preferably 15 to 75% by weight of the total of the semiconductor fine particles in the semiconductor fine particle dispersion.

  Next, the obtained semiconductor fine particle dispersion is applied onto a conductive substrate. As a coating method, a method using a device such as a slit coater, spin coater, roll coater, dip coater, a printing method such as screen printing, flexographic printing or gravure printing, a relatively simple method using a doctor blade, a bar coater, etc. However, it is not limited to this. The film thickness of the semiconductor electrode formed on the conductive substrate is about 5 to 15 μm, preferably about 10 μm. After coating in this way, it is dried so as not to cause cracks, peeling, etc., and fired in air at a temperature of about 500 ° C. to form a porous semiconductor electrode made of a semiconductor fine particle material.

  As the semiconductor fine particles, metal oxide fine particles are preferably used, alkaline earth metals such as magnesium, strontium and calcium, transition metals such as titanium, tin, zinc, indium, zirconium, niobium, tantalum, chromium, molybdenum and tungsten. These oxides and mixtures of these oxides are preferably used. Semiconductor fine particles may be formed by oxidizing the surface of highly conductive metal fine particles.

  A smaller particle size of the semiconductor fine particles is preferable because the surface area of the semiconductor electrode is increased and the photoelectric conversion efficiency is improved. However, the average particle size of the semiconductor fine particles is most desirably 5 to 100 nm, preferably 10 to 30 nm in view of the production, stability, ease of film formation and performance of the semiconductor fine particle dispersion.

  In addition, when forming semiconductor electrodes by sintering semiconductor fine particles, care must be taken because the surface state changes depending on the firing temperature. The most commonly used semiconductor electrode using titanium oxide (anatase) fine particles is most preferably fired at about 450 ° C.

  Moreover, in order to respond | correspond to a film substrate, the method of forming a semiconductor electrode by heating at 200 degrees C or less is also used suitably. One is a method of attaching particles to a substrate by electrophoresis as disclosed in JP-A-2002-100416. In addition, there is a method in which a titanium oxide sol developed for low-temperature firing, such as Solaronix Ti-Nanoxide DL or Showa Denko SP200, is applied and fired at about 150 ° C.

  In order to further improve the performance of the semiconductor electrode thus formed, the semiconductor electrode may be subjected to surface treatment such as chemical treatment with various chemicals or physical treatment such as ultraviolet light irradiation. For example, it is known that after forming a titanium oxide porous semiconductor electrode, a conversion efficiency is improved by dropping a titanium tetrachloride aqueous solution and holding it for several hours, and such treatment may be performed.

  As the dye to be carried on the semiconductor electrode, conventionally known dyes that can be stably dissolved in the solution composition used as the dye-containing liquid can be used. For example, various dyes such as a ruthenium polypyridinium complex, chlorophyll, porphyrin, phthalocyanine, triphenylmethane, fluorescein, rhodamine and other xanthene dyes, polymethine, squarylium and coumarin are used. The dye preferably has a functional group having some bond with the semiconductor electrode in order to smoothly transfer energy to the semiconductor electrode. For example, those having a polar group such as a carboxyl group, a phosphonyl group, an amino group, and a sulfone group and capable of forming a coordination or ester-like bond with the metal atom of the semiconductor electrode are preferable.

  Next, as a method of supporting the dye on the semiconductor electrode, for example, the semiconductor electrode substrate is immersed in a dye solution in which the dye is dissolved in a solvent such as alcohol, and the dye is adsorbed on the surface of the semiconductor electrode by refluxing as necessary. Methods and the like. The dye concentration in the dye solution is preferably about 0.1 mM to 1 mM, more preferably about 0.3 mM to 0.5 mM. The immersion time is preferably 12 hours at room temperature, 1 hour at about 40 ° C., and about 30 minutes at about 50 ° C. However, the degree of dyeing varies depending on the film formation state of the semiconductor electrode. It is necessary to adjust the temperature and immersion time as appropriate according to the type and treatment process.

  When dyeing is completed, excess dye may be washed with ethanol, acetonitrile or the like, and surface treatment may be performed with an organic acid such as acetic acid or a base such as t-butylpyridine as a reverse electron transfer prevention treatment to the electrolyte composition. .

<Counter substrate 11>
The counter electrode preferably has a catalytic action that promotes the reduction reaction of the electrolyte layer. Specifically, platinum deposited on a platinum electrode or carbon electrode, or carbon particles adsorbed are used. A substrate treated with a conductive polymer may be used instead of expensive platinum. PEDOT doped with iron p-toluenesulfonate in Synthetic Metals 1994, 66, 263 is preferably used.

<Manufacture of dye-sensitized solar cells>
On the semiconductor electrode of the semiconductor electrode substrate, an appropriate amount of the electrolyte composition is applied using a method such as screen printing, and the counter electrode side of the counter substrate is made to face. At this time, since the electrolyte composition has an appropriate viscosity, the two substrates are brought into close contact with each other by pressure bonding, but may be bonded with a material such as a double-sided tape having a constant film thickness in order to keep the substrate interval constant. It doesn't matter. It is also possible to bond both substrates by thermocompression bonding using a thermoplastic film. Furthermore, it is also possible to adhere both substrates or seal the periphery using a liquid adhesive. In this case, in order to keep the distance between the substrates constant, beads or the like serving as a spacer may be added in the adhesive or the electrolyte. Alternatively, a film having a certain film thickness may be sandwiched between parts separated from the light receiving surface and adhered. Alternatively, a spacer composition having a certain height may be fixed and formed on any substrate.

  Moreover, you may seal a photovoltaic cell so that electrolyte composition may not flow out. Although it does not restrict | limit especially as a sealing material, For example, a thermoplastic resin which consists of an epoxy resin, a silicone resin, an ethylene / methacrylic acid copolymer, a glass frit etc. are used suitably. At this time, it is necessary to consider that adhesiveness is not impaired by the protrusion of the electrolyte composition, such as adjusting the application amount of the electrolyte composition and providing a sufficient gap.

  Moreover, in order to promote the exudation of the electrolyte into the semiconductor electrode, heating may be performed to the extent that there is no problem.

  Further, in order to protect the entire solar battery cell, the entire lead-out line may be secured with a lead wire or the like, and the whole may be laminated with a film or coated with a liquid resin.

<Manufacture of electrolyte base>
An alumina hydrate having an average particle size of about 0.2 μm (“Disperal HP18” manufactured by SASOL) as a solid content is 20 wt%, acetic acid 0.4 wt%, and water 99.6 wt%. The product was stirred with “AR100”) to produce a viscous liquid electrolyte base 1.

  Furthermore, electrolyte raw materials 2 to 4 were produced in the same manner except that the compositions shown in Table 2 were used. Electrolyte base 3 has a composition with little moisture, and has become mako-like with white turbidity and a large granular lump. The electrolyte base 4 has a composition with a lot of water and is almost liquid.

<Example 1>
Electrolyte base 1 and electrolyte solution (high-boiling-point solvent liquid electrolyte in which polyethylene glycol having an average molecular weight of 200 is used as a solvent, 0.5M of lithium iodide and 0.05M of iodine are dissolved) are mixed at a ratio shown in Table 3, The mixture was stirred with a revolutionary stirring device (“AR100” manufactured by Shinky Corporation) to obtain a uniform paste-like electrolyte composition.

  Using this electrolyte composition, a dye-sensitized solar cell was produced as follows.

First, a titanium oxide fine particle dispersion paste (“Ti-Nanoxide D” manufactured by Solaronics) on a glass substrate (SnO ₂ : F film-formed glass substrate, manufactured by Nippon Sheet Glass Co., Ltd., sheet resistance 10 Ω / □) formed with a transparent conductive film Was applied by a doctor blade method, dried at room temperature, and then baked in an electric furnace at 500 ° C. for 30 minutes to obtain a porous titanium oxide semiconductor electrode (film thickness: 11 μm). Further, this semiconductor electrode substrate was immersed in a 0.4 mM ethanol solution of ruthenium 535bisTBA (solaronix) for 12 hours and then washed with ethanol and acetonitrile to adsorb the dye to the semiconductor electrode (effective area 0.5 cm ² ).

  Then, apply an appropriate amount of electrolyte composition to the semiconductor electrode side of the semiconductor electrode substrate with a spatula, sandwich a 25 μm-thick film as a spacer, match the counter substrate (conductive glass substrate sputtered with platinum), and adhere tightly so that bubbles do not enter And fixed with a clip to complete a dye-sensitized solar cell.

Using a 1 kw xenon lamp obtained by cutting ultraviolet light having a wavelength of 420 nm or less using a UV cut filter, irradiation was performed so that the amount of light on the light receiving surface was 100 mW / cm ^2, and the photoelectric conversion efficiency was measured. The results are shown in Table 4.

  Moreover, this cell was left for 1 week without sealing the periphery, and the photoelectric conversion efficiency was measured. The results are shown in Table 4. Even after being left for one week, no liquid or electrolyte flowed out from the surroundings, and the conversion efficiency was equivalent.

<Examples 2-5, Comparative Examples 1-3>
Except having used the electrolyte composition shown in Table 3, the dye-sensitized solar cell was comprised like Example 1 and evaluated similarly. The results are shown in Table 4.

  In Comparative Example 2, an attempt was made to prepare an electrolyte composition using the electrolyte base 3, but it was difficult to uniformly mix the electrolyte base and it became a massive solid. The conversion efficiency could not be measured. This is probably because the amount of water with respect to the alumina hydrate is too small, and the electrolyte base has become mamako-like.

  In Comparative Example 3, an attempt was made to prepare an electrolyte composition by using the electrolyte base 4 and mixing it with various components of the electrolyte solution at various ratios, but no paste-like electrolyte composition was obtained. It seems that pasting did not occur because there was too little alumina hydrate relative to water.

  From these results, when the paste-like electrolyte is produced under a certain condition, a photoelectric conversion device having the same or better characteristics can be produced by simply applying the paste-like electrolyte on the semiconductor electrode and sandwiching it with the counter electrode. When the amount of alumina added is 5 wt% or less, pasting is insufficient and there is a risk of electrolyte outflow, and the characteristics are less different from those before pasting. If the total of alumina and moisture reaches 50 wt%, the efficiency will be reduced. Preferably, the total of alumina and moisture is preferably about 30 wt%, and the alumina solid content is preferably about 10 wt%.

<Example 6>
A paste-like electrolyte composition was obtained in the same manner as in Example 1 except that alumina hydrate having an average particle size of 100 nm (“DISPAL23N4-80” manufactured by SASOL) was used. A battery cell was constructed and evaluated. The results are shown in Table 4.

<Example 7>
A paste-like electrolyte composition was obtained in the same manner as in Example 1 except that alumina hydrate having an average particle diameter of 300 nm (“DISPAL40” manufactured by SASOL) was used, and using this, a dye-sensitized solar cell was obtained. Was constructed and evaluated. The results are shown in Table 4.

  In addition, the electrolyte composition is cloudy and is considered to be inferior in transparency compared to other samples.

<Comparative example 4>
Hydrophobic silica (trade name “AEROSIL 300”, manufactured by Nippon Aerosil Co., Ltd.) 20 wt%, acetic acid 0.4 wt%, water 79.6 wt% of primary particles having an average diameter of about 7 nm were mixed with a revolving stirrer (Sinky Corporation “ When stirred with AR100 "), the viscosity was very low and a paste similar to that of the electrolyte base 1 could not be obtained.

<Comparative Example 5>
When 13.9 wt% of hydrophilic silica used in Comparative Example 4, 2.8 wt% of acetic acid, and 83.3 wt% of water were stirred with a self-revolving stirrer (“AR100” manufactured by Sinky Corporation), the same as the electrolyte base 1 A paste of was obtained.

  This paste and the electrolytic solution used in Example 1 were mixed and stirred with a self-revolving stirrer (“AR100” manufactured by Shinky Corp.), but the viscosity was very low at any ratio and had an appropriate viscosity. A paste electrolyte without fluidity was not obtained.

<Comparative Example 6>
12.46 wt% of the hydrophilic silica used in Comparative Example 4 as a solid content and 87.54 wt% of the electrolyte used in Example 1 were mixed and stirred with a self-revolving stirrer (“AR100” manufactured by Sinky). A uniform paste-like electrolyte was obtained.

Using this electrolyte, a dye-sensitized solar cell was constructed and evaluated in the same manner as in Example 1.
The results are shown in Table 4.

It is a schematic sectional drawing which shows an example of the dye-sensitized solar cell of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base body 2 Conductive layer 3 Semiconductor electrode 4 Electrolyte layer 5 Counter electrode 6 Base body 10 Semiconductor electrode substrate 11 Counter substrate

Claims (4)

  An electrolyte composition for use in a dye-sensitized solar cell that supports a dye on a semiconductor and converts light energy into electric energy by photoexcitation of the dye, and contains at least aluminum oxide and water, and is in a paste form An electrolyte composition.   2. The electrolyte composition according to claim 1, comprising 1 to 20 wt% of aluminum oxide and 5 to 30 wt% of water.   A dye-sensitized solar cell comprising an electrolyte layer made of the electrolyte composition according to claim 1.   3. A dye sensitizing method comprising: a step of applying the electrolyte composition according to claim 1 or 2 to a semiconductor on an electrode to form an electrolyte layer; and a step of providing a counter electrode on the electrolyte layer. A method for manufacturing a solar cell.

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