JP2004119279A - Dye-sensitizing solar cell and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dye-sensitizing solar cell with improved energy conversion efficiency. <P>SOLUTION: In the dye-sensitizing solar cell equipped with a semiconductor electrode 4, an opposing electrode 5 and an electrolyte composition 9; a film-like matter containing at least one kind of organic compound selected from among a group of alkoxysilane containing fluorine atom, chlorosilane containing fluorine atom, silanol containing fluorine atom, pyridines containing fluorine atom and imidazoles containing fluorine atom, and dyes are formed at least on a part of the surface of the semiconductor electrode 4. <P>COPYRIGHT: (C)2004,JPO

Description

【００６２】
（比較例１）
フルオロアルキルオリゴマー置換トリメトキシシランの処理を行なわない以外は、実施例１と同様にして色素増感型太陽電池を製造した。
【００６３】
（比較例２）
メチルトリメトキシシランが溶解されたトルエン溶液に、色素吸着後のｎ型半導体電極保持基板を浸漬することにより、半導体電極表面にメチルトリメトキシシランを吸着させること以外は、前述した実施例１と同様にして色素増感型太陽電池を製造した。
【００６４】
得られた実施例１〜１８及び比較例１〜２の太陽電池について、１００ｍＷ／ｃｍ^２の擬似太陽光を照射した際のエネルギー変換効率を測定し、その結果を下記表１に示す。
【００６５】
【表１】

【００６６】
表１から明らかなように、半導体電極の表面にＦ置換の有機化合物と色素とを含有する膜状物が形成されている実施例１〜８の太陽電池は、Ｆ置換有機化合物による処理を行わない比較例１の太陽電池と、Ｆ原子を含まない有機化合物で処理を行う比較例２の太陽電池に比較してエネルギー変換効率に優れていることがわかる。特に、フッ素原子を含有するアルコキシシランを用いる実施例１〜４の太陽電池は、高いエネルギー変換効率を得られることがわかる。
【００６７】
（実施例９〜１３）
ゲル電解質を用いる代わりに、メチルプロピルイミダゾリウムアイオダイドにｔ−ブチルピリジンを０．５８Ｍ、ＬｉＩを０．５Ｍ、Ｉ_２を０．３Ｍ、水を１０ｗｔ％を添加した電解液を用いると共に、フッ素置換有機化合物の種類および吸着方法を下記表２に示すように変更すること以外は、前述した実施例１または実施例２で説明したのと同様な手法により色素増感型太陽電池を製造した。
【００６８】
（比較例３）
ゲル電解質を用いる代わりに前述した実施例９で説明した電解液を用いると共に、フルオロアルキルオリゴマー置換トリメトキシシランの処理を行なわない以外は、実施例１と同様にして色素増感型太陽電池を製造した。
【００６９】
（比較例２）
メチルトリメトキシシランが溶解されたトルエン溶液に、色素吸着後のｎ型半導体電極保持基板を浸漬することにより、半導体電極表面にメチルトリメトキシシランを吸着させることと、ゲル電解質の代わりに前述した実施例９で説明した電解液を用いること以外は、前述した実施例１と同様にして色素増感型太陽電池を製造した。
【００７０】
得られた実施例９〜１３及び比較例３〜４の太陽電池について、１００ｍＷ／ｃｍ^２の擬似太陽光を照射した際のエネルギー変換効率を測定し、その結果を下記表２に示す。
【００７１】
【表２】

【００７２】
表２から明らかなように、実施例９〜１３の太陽電池は、水による色素の加水分解がほとんど起こらず、エネルギー変換効率が比較例３，４の太陽電池に比較して高いことが理解できる。また、実施例９〜１３の太陽電池は、８０℃で１週間加熱し再度エネルギー変換効率を測定した際にほとんど効率の減少がおこらなかった。特に、フッ素原子を含有するアルコキシシランを用いる実施例９〜１０の太陽電池は、高いエネルギー変換効率を得られることがわかる。
【００７３】
（実施例１４）
１−メチル−３−プロピルイミダゾリウムアイオダイド中によう素０．３Ｍ、ｔ−ブチルピリジン０．５８Ｍ、ＬｉＩ０．５Ｍを溶解させた溶液に水１０ｗｔ％加えた電解質組成物をゲル電解質の代わりに用いること以外は、実施例２と同様にして色素増感型太陽電池を製造した。この太陽電池のエネルギー変換効率を前述したのと同様な条件で測定したところ、５．０％であった。また、８０℃で１週間加熱し再度エネルギー変換効率を測定したところ、ほとんど効率の減少がおこらなかった。
【００７４】
（実施例１５）
１−メチル−３−プロピルイミダゾリウムアイオダイド中によう素０．３Ｍ、ｔ−ブチルピリジン０．５８Ｍ、ＬｉＩ０．５Ｍを溶解させた溶液に水５５ｗｔ％加えた電解質組成物をゲル電解質の代わりに用いること以外は、実施例２と同様にして色素増感型太陽電池を製造した。この太陽電池のエネルギー変換効率を前述したのと同様な条件で測定したところ、１％であった。さらに、この太陽電池を８０℃で１週間加熱し再度エネルギー変換効率を測定したところ、０．９％であった。
【００７５】
（比較例５）
フルオロアルキルオリゴマー置換トリメトキシシランの処理を行なわないこと以外は、実施例１５と同様にして色素増感型太陽電池を製造した。この太陽電池のエネルギー変換効率を前述したのと同様な条件で測定したところ、０．９％であった。さらに、この太陽電池を８０℃で１週間加熱し再度エネルギー変換効率を測定したところ、０．１％に出力は低下した。
【００７６】
【発明の効果】
以上詳述したように本発明によれば、エネルギー変換効率が向上された色素増感型太陽電池及びその製造方法を提供することができる。
【図面の簡単な説明】
【図１】本発明に係る色素増感型太陽電池の製造工程の一例を示す断面図。
【図２】本発明に係る色素増感型太陽電池の一例を示す断面図。
【符号の説明】
１…ガラス基板
２…透明導電膜
３…酸化チタン微粒子
４…半導体電極
５…導電膜
６…対向基板
７，１０…エポキシ樹脂
８…注入ノズル
９…電解質組成物
１１…入射光。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dye-sensitized (photosensitized) solar cell and a method for manufacturing the same.
[0002]
[Prior art]
A general photosensitized solar cell is constituted by, for example, as described in JP-A-1-220380, in which a dye is supported on the surface of a transparent semiconductor layer composed of metal oxide fine particles. An electrode (oxide electrode), a transparent electrode facing the electrode, and a liquid carrier moving layer interposed between the two electrodes are provided. Such a solar cell is called a wet-type photosensitized solar cell because the carrier transfer layer is liquid.
[0003]
The photosensitized solar cell as described above operates through the following processes. That is, light incident from the transparent electrode side reaches the dye carried on the surface of the transparent semiconductor layer, and excites the dye. The excited dye quickly transfers electrons to the transparent semiconductor layer. On the other hand, the dye positively charged by losing electrons is electrically neutralized by receiving electrons from ions diffused from the carrier transfer layer. The ions that have passed the electrons diffuse into the transparent electrode and receive the electrons. The wet photosensitized solar cell operates by using the oxide electrode and the transparent electrode opposed thereto as a negative electrode and a positive electrode, respectively.
[0004]
On the other hand, in paragraph [0043] of JP-A-2001-102103, after a dye is supported on a semiconductor surface to form a dye-carrying part, a charge-transfer controlling molecule is supported and a charge-transfer controlling molecule supporting part is formed. By forming, the surface of the semiconductor layer on which the dye-carrying portion is not formed is covered with charge transfer control molecules, preventing the transfer of charge from the surface of the semiconductor layer into the charge transport layer, open voltage, photoelectric conversion efficiency. It is described that a semiconductor electrode having excellent optical characteristics such as the above is obtained. Further, as the charge transfer control molecule, a polymer containing a silicon compound, a tin compound, a sulfonate, a sulfate, or a phosphate is used (paragraph [0023]).
[0005]
However, according to the dye-sensitized solar cell using a semiconductor electrode containing such a charge transfer controlling molecule, there is a problem that high energy conversion efficiency cannot be obtained because the dye is hydrolyzed.
[0006]
[Patent Document 1]
JP-A 1-220380 (claims)
[0007]
[Patent Document 2]
JP 2001-102103 A (claims, paragraphs [0023], [0043])
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide a dye-sensitized solar cell with improved energy conversion efficiency and a method for manufacturing the same.
[0009]
[Means for Solving the Problems]
The dye-sensitized solar cell according to the present invention is a dye-sensitized solar cell including a semiconductor electrode, a counter electrode, and an electrolyte composition.
At least a portion of the surface of the semiconductor electrode is made of a fluorine atom-containing alkoxysilane, a fluorine atom-containing chlorosilane, a fluorine atom-containing silanol, a fluorine atom-containing pyridine, and a fluorine atom-containing imidazole. It is characterized in that a film containing at least one organic compound selected from the group and a dye is formed.
[0010]
The method for producing a dye-sensitized solar cell according to the present invention, a step of adsorbing a dye on the surface of the semiconductor electrode,
Immersing the semiconductor electrode in a solution containing an organic compound, or exposing the semiconductor electrode to a vapor atmosphere of an organic compound,
The organic compound is a fluorine atom-containing alkoxysilane, a fluorine atom-containing chlorosilane, a fluorine atom-containing silanol, a fluorine atom-containing pyridines and a fluorine atom-containing imidazoles at least selected from the group consisting of It is characterized by one type.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The dye-sensitized solar cell according to the present invention is a dye-sensitized solar cell including a semiconductor electrode, a counter electrode, and an electrolyte composition, wherein at least a part of the surface of the semiconductor electrode contains a fluorine atom. Alkoxysilane, chlorosilane containing a fluorine atom, silanol containing a fluorine atom, at least one F-substituted organic compound selected from the group consisting of pyridines containing a fluorine atom and imidazoles containing a fluorine atom, A film-like substance containing a dye is formed.
[0012]
The semiconductor electrode is formed from a sintered body of semiconductor particles. A monomolecular film is formed by the monomolecular adsorption of the dye on the surface of such a semiconductor particle, and the F-substituted organic compound of the type described above is physically adsorbed or chemically bonded to the surface of the semiconductor particle on which the monomolecular film is not formed. The result of the adsorption is one form of a film used in the present invention. The adsorption state will be specifically described. For example, the OR group of alkoxysilane, the Cl of chlorosilane, and the OH group of silanol are formed by the semiconductor (for example, TiO 2) of the semiconductor electrode.₂) Can be adsorbed on the surface of the semiconductor electrode by chemical bonding. On the other hand, pyridines and imidazoles each have a nitrogen atom as a semiconductor electrode (for example, TiO.sub.2).₂) And an acid-base reaction.
[0013]
Further, the F-substituted organic compound described above has low affinity for water due to the water repellency of fluorine and its steric hindrance. As a result, the F-substituted organic compound can suppress the dye from being hydrolyzed by the water taken into the cell during the manufacturing process and the water added to the electrolyte, so that the dye having a high energy conversion efficiency can be suppressed. A sensitized solar cell can be realized.
[0014]
Hereinafter, the semiconductor electrode, the counter electrode, and the electrolyte composition will be described.
[0015]
1) Semiconductor electrode
The semiconductor electrode is desirably formed on a substrate having a light receiving surface such as a glass substrate via a transparent conductive film.
[0016]
The semiconductor electrode preferably contains a transparent semiconductor that absorbs less in the visible light region. As such a semiconductor, an n-type semiconductor (for example, a metal oxide semiconductor) is preferable. Specifically, oxides of transition metals such as titanium, zirconium, hafnium, strontium, zinc, indium, yttrium, lanthanum, vanadium, niobium, tantalum, chromium, molybdenum or tungsten, SrTiO₃, CaTiO₃, BaTiO₃, MgTiO₃, SrNb₂O₆Or a composite oxide or oxide mixture thereof, GaN, or the like.
[0017]
On at least a part of the surface of the semiconductor electrode, a film-like material having the composition described above is formed. The F-substituted organic compound contained in the film will be described.
[0018]
As the alkoxysilane containing a fluorine atom, an organoalkoxysilane in which at least a part of a hydrogen atom of an alkyl group directly bonded to a Si atom is substituted with a fluorine atom is preferable. This is because such an organoalkoxysilane is excellent in hydrophobicity and adsorptivity to a semiconductor. Specifically, 3,3,3-trifluoropropyltrimethoxysilane, 1H, 1H, 2H, 2H-perfluorooctyltrimethoxysilane, 1H, 1H, 2H, 2H-perfluorodecyltrimethoxysilane, fluoroalkyl Oligomer-substituted trimethoxysilane (for example, the trade name of Daikin Industries, Ltd. is Optool DSX).
[0019]
As the chlorosilane containing a fluorine atom, an organochlorosilane in which at least a part of hydrogen atoms of an alkyl group directly bonded to a Si atom is substituted with a fluorine atom is preferable. This is because such organochlorosilane is excellent in hydrophobicity and adsorptivity to a semiconductor. Specifically, 3,3,3-trifluoropropylchlorosilane, 1H, 1H, 2H, 2H-perfluorooctylchlorosilane, 1H, 1H, 2H, 2H-perfluorodecylchlorosilane and the like can be mentioned.
[0020]
As the silanol containing a fluorine atom, an organosilanol in which at least a part of a hydrogen atom of an alkyl group directly bonded to a Si atom is substituted with a fluorine atom is preferable. Specifically, 3,3,3-trifluoropropylsilanetriol, 1H, 1H, 2H, 2H-perfluorooctylsilanetriol, 1H, 1H, 2H, 2H-perfluorodecylsilanetriol and the like can be mentioned. .
[0021]
As the pyridine containing a fluorine atom, pyridine in which at least one hydrogen atom is substituted by a fluorine atom, pyridine having an alkyl group in which at least one hydrogen atom is substituted by a fluorine atom as a substituent, and the like are preferable. This is because such pyridines are excellent in both hydrophobicity and adsorptivity to a semiconductor. Specifically, 2-fluoropyridine, 2-methoxy-3- (trifluoromethyl) pyridine, 2-methoxy-5- (trifluoromethyl) pyridine, 2-mercapto-3- (trifluoromethyl) pyridine, -Mercapto-5- (trifluoromethyl) pyridine, 2-hydroxy-3- (trifluoromethyl) pyridine, 2-hydroxy-4- (trifluoromethyl) pyridine, 2-hydroxy-5- (trifluoromethyl) pyridine , 3,5-dichloro-2,4,6-trifluoropyridine and the like.
[0022]
As the imidazole containing a fluorine atom, imidazole in which at least one hydrogen atom is substituted by a fluorine atom, imidazole having an alkyl group in which at least one hydrogen atom is substituted by a fluorine atom as a substituent are preferable. Specifically, 1-methyl-2-trifluoropropylimidazole and the like can be mentioned.
[0023]
Among alkoxysilanes, chlorosilanes, silanols, pyridines and imidazoles containing a fluorine atom, in particular, alkoxysilane is used as a semiconductor electrode (for example, TiO2).₂) Is most preferable because it chemically reacts with Ti-OH present on the surface to form a strong Ti-O-Si bond and exists stably.
[0024]
Further, an organic acid or an organic acid salt as described below may be used in combination with an F-substituted organic compound selected from alkoxysilane, chlorosilane, silanol, pyridines and imidazoles containing a fluorine atom.
[0025]
Examples of the organic acid containing a fluorine atom include, for example, 2,5-difluorobenzoic acid, 2,6-difluorobenzoic acid, 3,4-difluorobenzoic acid, pentafluorobenzoic acid, pentafluoropropanoic acid, and nonafluoropentanoic acid , Perfluorohexanoic acid, perfluoroheptanoic acid, perfluorooctanoic acid, perfluorononanoic acid, perfluorotetradecanoic acid, 3,5-bis (trifluoromethyl) phenylacetic acid, 2,4-bis (trifluoromethyl) benzoic acid Acid, 2,6-bis (trifluoromethyl) benzoic acid, 3,5-bis (trifluoromethyl) benzoic acid, 2,2-bis (3-carboxyphenyl) hexafluoropropane, 2,2-bis (4 -Carboxyphenyl) hexafluoropropane and the like.
[0026]
Examples of the organic acid salt containing a fluorine atom include, for example, pentafluorobenzoic acid chloride, nonafluoropentanoic acid chloride, pentafluoropropanoic acid chloride, perfluorohexanoic acid chloride, perfluoroheptanoic acid chloride, perfluorochemical Octanoic acid chloride, perfluorononanoic acid chloride, perfluorotetradecanoic acid chloride and the like can be mentioned.
[0027]
The adsorption area of the F-substituted organic compound is preferably set so as to fall within the range of 0.001 to 1% when the specific surface area of the semiconductor electrode by the BET method is 100%. This is for the reason described below. If the adsorption area of the F-substituted organic compound is less than 0.0001%, the effect of the F-substituted organic compound may not be sufficiently obtained. On the other hand, if the adsorption area of the F-substituted organic compound exceeds 1%, the surface of the dye is covered with the F-substituted organic compound, so that the activity of the dye may be reduced and a high energy conversion efficiency may not be obtained.
[0028]
It is desirable that the dye is monomolecularly adsorbed on the surface of the semiconductor electrode. Examples of the dye include a ruthenium-tris type transition metal complex, a ruthenium-bis type transition metal complex, an osmium-tris type transition metal complex, an osmium-bis type transition metal complex, and a ruthenium-cis-diaqua-bipyridyl complex. , Phthalocyanine, and porphyrin.
[0029]
It is preferable that the transparent conductive film has little absorption in the visible light region and has conductivity. As such a transparent conductive film, a tin oxide film doped with fluorine or indium, a zinc oxide film doped with fluorine or indium, or the like is preferable. Further, from the viewpoint of improving conductivity and preventing an increase in resistance, it is desirable to wire a low-resistance metal or carbon matrix in combination with the transparent conductive film.
[0030]
2) Counter electrode
The counter electrode can be formed from, for example, a metal film such as platinum, gold, and silver, a carbon film, a tin oxide film, a tin oxide film doped with fluorine, a zinc oxide film, or the like. Platinum is particularly preferable in consideration of durability against the electrolyte.
[0031]
The counter electrode is preferably formed on a counter substrate such as a glass substrate. Note that platinum can be attached to the opposite substrate by electrochemical or sputtering.
[0032]
3) Electrolyte composition
This electrolyte composition may be liquid or gel.
[0033]
The electrolyte composition preferably contains a reversible redox couple. Reversible redox couples include, for example, iodine (I₂) And iodides, iodides, bromides, hydroquinones, TCNQ complexes and the like. In particular, I provided from a mixture of iodine and iodide⁻And I₃ ⁻And a redox couple consisting of
[0034]
It is desirable that the redox couple as described above shows a redox potential that is 0.1 to 0.6 V lower than the oxidation potential of the dye. A redox couple exhibiting a redox potential 0.1 to 0.6 V lower than the oxidation potential of the dye is, for example, I⁻Reducing species such as can accept holes from the oxidized dye. By including such a redox couple in the electrolyte, the speed of charge transport between the n-type semiconductor electrode and the conductive film can be increased, and the open-circuit voltage can be increased.
[0035]
It is desirable that the electrolyte composition contains iodide. Examples of the iodide include an iodide of an alkali metal, an iodide of an organic compound, a molten salt of an iodide, and the like.
[0036]
Examples of the molten salt of iodide include iodides of heterocyclic nitrogen-containing compounds such as imidazolium salts, pyridinium salts, quaternary ammonium salts, pyrrolidinium salts, pyrazolidium salts, isothiazolidinium salts, and isoxazolidinium salts. Can be used.
[0037]
Examples of the molten salt of the iodide include 1,3-dimethylimidazolium iodide, 1-ethyl-3-methylimidazolium iodide, 1-methyl-3-propylimidazolium iodide, and 1-methyl-3-. Pentyl imidazolium iodide, 1-methyl-3-isopentyl imidazolium iodide, 1-methyl-3-hexylimidazolium iodide, 1-methyl-3-isohexyl (branched) imidazolium iodide, 1-methyl- 3-ethyl imidazolium iodide, 1,2-dimethyl-3-propyl imidazol iodide, 1-ethyl-3-isopropyl imidazolium iodide, 1-propyl-3-propyl imidazolium iodide, pyrrolidinium iodide Etc. That. These iodide molten salts can be used alone or in combination of two or more. Further, the content thereof is preferably about 0.005 mol / L or more and about 7 mol / L or less in the electrolyte composition. When the amount is less than 0.005 mol / L, it is difficult to obtain a sufficient effect. On the other hand, if it exceeds 7 mol / L, the viscosity may be high and the ionic conductivity may be significantly reduced.
[0038]
It is preferable that the iodine content in the electrolyte composition be in the range of 0.01 mol / L or more and 3 mol / L or less. Iodine mixes with iodide in the electrolyte composition and acts as a reversible redox couple. Therefore, when the content of iodine is less than 0.01 mol / L, there is a possibility that the oxidant of the redox couple becomes insufficient and it becomes difficult to transport charges. On the other hand, if it exceeds 3 mol / L, the light absorption of the solution increases, and it may not be possible to efficiently provide light to a semiconductor such as titania. Note that the content of iodine is more preferably 0.03 mol / L or more and 1 mol / L or less.
[0039]
The electrolyte composition may further contain an organic solvent. When the organic solvent is contained, the viscosity of the electrolyte composition can be further reduced, so that the electrolyte composition is easily permeated into the semiconductor electrode.
[0040]
Examples of the organic solvent that can be used include cyclic carbonates such as ethylene carbonate (EC) and propylene carbonate (PC); linear carbonates such as dimethyl carbonate, methyl ethyl carbonate, and diethyl carbonate; γ-butyrolactone, acetonitrile, and propionic acid. Methyl and ethyl propionate. Furthermore, cyclic ethers such as tetrahydrofuran and 2-methyltetrahydrofuran; linear ethers such as dimethoxyethane and diethoxyethane; nitrile solvents such as acetonitrile, propionitrile, glutaronitrile, and methoxypropionitrile; Can be These organic solvents can be used alone or as a mixture of two or more.
[0041]
The content of the organic solvent is not particularly limited, but is preferably 80% by weight or less in the electrolyte composition. If the content of the organic solvent exceeds 30% by weight, the performance may be degraded due to volatilization. Therefore, the content of the organic solvent is more preferably set to 30% by weight or less.
[0042]
Preferably, the electrolyte composition contains water. The electrolyte composition containing water can further increase the energy conversion efficiency of the dye-sensitized solar cell. The content of water in the electrolyte composition is preferably in the range of 0.01% by weight to 50% by weight. A more preferred range for the water content is 0.1% to 30% by weight, and the most preferred range is 1% to 10% by weight.
[0043]
The dye-sensitized solar cell according to the present invention is manufactured, for example, by the method described below.
[0044]
First, a substrate having a light receiving surface, for example, a glass substrate is prepared, and a transparent conductive film and an n-type semiconductor electrode are sequentially formed on the inner surface thereof. The n-type semiconductor electrode holding substrate is immersed in a solution of the dye dissolved in a medium such as ethanol, so that the dye is adsorbed on the surface of the n-type semiconductor (for example, titania) by an ester bond. Next, the n-type semiconductor electrode holding substrate is immersed in a solution in which the above-described organic compound is dissolved in an organic solvent, or the n-type semiconductor electrode holding substrate is exposed to the vapor atmosphere of the above-described organic compound, thereby forming a semiconductor surface. The organic compound is adsorbed on the unadsorbed portion of the dye by physical adsorption or chemical bonding. As a method of adsorbing the F-substituted organic compound, a method of adsorbing the vapor of the F-substituted organic compound is preferable. According to this method, the dye surface can be prevented from being covered with the F-substituted organic compound, and a decrease in the activity of the dye can be suppressed, so that higher energy conversion efficiency can be obtained.
[0045]
On the other hand, a conductive film is formed as a counter electrode on a substrate having a light receiving surface, for example, a glass substrate, and the counter electrode and the n-type semiconductor electrode are opposed to each other to assemble a battery unit.
[0046]
Next, after the electrolyte composition is injected into the gap between the n-type semiconductor electrode and the counter electrode, the battery unit is sealed. When the electrolyte composition used here is a gel electrolyte precursor composition, the dye-sensitized solar cell according to the present invention can be obtained by gelling the gel electrolyte precursor composition.
[0047]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0048]
(Example 1)
First, as a material for the n-type semiconductor electrode, a commercially available paste (manufactured by Solaronix, Switzerland) containing high-purity titanium oxide (anatase) powder having an average primary particle size of about 10 to 20 nm was prepared.
[0049]
Fluorine-doped SnO on glass substrate 1₂A transparent electrode (6Ω / □) 2 was provided, and the above-mentioned paste was printed thereon by a screen printing method, and heat-treated at a temperature of 450 ° C. Thus, an n-type semiconductor electrode made of titanium oxide (anatase) particles and having a thickness of 2 μm was formed.
[0050]
By repeating this screen printing and heat treatment a plurality of times, an n-type semiconductor electrode 4 composed of titanium oxide particles 3 in the anatase phase is finally formed on the fluorine-doped tin oxide conductive film 2 (transparent conductive film 2) by 8 μm. Formed with a thickness of The roughness factor of the n-type semiconductor electrode 4 was 1500. The roughness factor was determined from the nitrogen adsorption amount with respect to the projected area of the substrate.
[0051]
On the other hand, cis-bis (thiocyanato) -N, N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) dihydrate) was dissolved in dry ethanol, and 3 × 10^-4A dry ethanol solution of M was prepared. The above-mentioned n-type semiconductor electrode 4 was immersed in this solution (temperature: about 80 ° C.) for 4 hours, and then pulled up in an argon stream. As a result, the ruthenium complex as a dye was carried on the surface of the n-type semiconductor electrode 4. Next, a fluoroalkyl oligomer-substituted trimethoxysilane (trade name: Optool DSX, manufactured by Daikin Industries, Ltd.) is dissolved in a perfluorocarbon-based diluent, and the n-type semiconductor electrode holding substrate is immersed in the obtained solution for 1 minute. At a speed of 10 mm and air-dried. The adsorption area of the fluoroalkyl oligomer-substituted trimethoxysilane was equivalent to 0.001% when the specific surface area of the n-type semiconductor electrode measured by the BET method was 100%.
[0052]
Further, a fluorine-doped tin oxide electrode 5 (conductive film 5) was formed on a glass substrate 6 having platinum adhered to the surface. The counter electrode 5 was placed on the substrate 1 on which the above-described n-type semiconductor electrode 4 was formed via a spacer having a diameter of 15 μm. Furthermore, the periphery was solidified and fixed with epoxy resin 7 except for the injection port for the electrolyte composition.
[0053]
Through the above operation, a photoelectric conversion element unit as shown in FIG. 1A was obtained.
[0054]
The electrolyte composition was prepared as follows. First, in 100 ml of acetonitrile, 0.5 mol / L of lithium iodide (LiI), 0.3 mol / L of methylhexylimidasolium iodide, 0.5 mol / L of t-butylpyridine, and 0.05 mol / L of iodine were used. Was dissolved to prepare an electrolyte composition.
[0055]
Next, as shown in FIG. 1B, an electrolyte composition 9 was injected from an injection nozzle 8 into the opening of the photoelectric conversion unit. The electrolyte composition 9 penetrated into the n-type semiconductor electrode 4 and was injected between the n-type semiconductor electrode 4 and the tin oxide electrode 5 as shown in FIG.
[0056]
Subsequently, as shown in FIG. 1D, the opening of the photoelectric conversion unit is sealed with an epoxy resin 10 and then heated at 60 ° C. for 30 minutes on a hot plate to gel the electrolyte composition, and A conversion element, that is, a dye-sensitized solar cell was manufactured. FIG. 2 shows a cross-sectional view of the obtained solar cell.
[0057]
As shown in FIG. 2, a transparent conductive film 2 and a transparent n-type semiconductor electrode 4 are sequentially formed on a glass substrate 1. Since the n-type semiconductor electrode 4 is formed from an aggregate of the fine particles 3, the surface area is extremely large. The dye is adsorbed on the surface of the n-type semiconductor electrode 4 as a single molecule, and the fluoroalkyl oligomer-substituted trimethoxysilane is adsorbed mainly on the non-dye adsorbed portion. The surface of the n-type semiconductor electrode 4 can have a fractal shape having self-similarity like a resin-like structure. On the other hand, the counter electrode 5 made of a conductive film is formed on a glass substrate 6.
[0058]
The gel electrolyte layer 9 is held by pores in the transparent n-type semiconductor electrode 4 and is interposed between the n-type semiconductor electrode 4 and the counter electrode 5. When light 11 enters from the glass substrate 1 side in such a dye-sensitized solar cell, first, the dye adsorbed on the surface of the n-type semiconductor electrode 4 absorbs the incident light 11 and is excited. . The excited dye passes electrons to the n-type semiconductor electrode 4 and passes holes to the gel electrolyte layer 9 to perform photoelectric conversion.
[0059]
(Example 2)
An n-type semiconductor electrode after dye adsorption in saturated vapor of a solution in which a fluoroalkyl oligomer-substituted trimethoxysilane (trade name of Optool DSX manufactured by Daikin Industries, Ltd.) is dissolved in a perfluorocarbon-based diluent at 0.1% by weight. A dye-sensitized solar cell was manufactured in the same manner as in Example 1 except that the holding substrate was allowed to stand for 60 minutes to adsorb the fluorine-substituted organic substance.
[0060]
(Examples 3 to 8)
A dye-sensitized solar cell was manufactured in the same manner as described in Example 1 or Example 2 above, except that the type of the fluorine-substituted organic compound and the adsorption method were changed as shown in Table 1 below. . The structural formula of 3,3,3-trifluoropropyltrimethoxysilane which is the fluorine-substituted organic compound used in Example 3 is shown in the following chemical formula 1.
[0061]
Embedded image

[0062]
(Comparative Example 1)
A dye-sensitized solar cell was manufactured in the same manner as in Example 1, except that the treatment with the fluoroalkyl oligomer-substituted trimethoxysilane was not performed.
[0063]
(Comparative Example 2)
Same as Example 1 described above, except that methyltrimethoxysilane is adsorbed on the surface of the semiconductor electrode by immersing the n-type semiconductor electrode holding substrate after dye adsorption in a toluene solution in which methyltrimethoxysilane is dissolved. Thus, a dye-sensitized solar cell was manufactured.
[0064]
For the obtained solar cells of Examples 1 to 18 and Comparative Examples 1 and 2, 100 mW / cm²The energy conversion efficiency when simulated sunlight was irradiated was measured, and the results are shown in Table 1 below.
[0065]
[Table 1]

[0066]
As is clear from Table 1, the solar cells of Examples 1 to 8 in which a film containing an F-substituted organic compound and a dye were formed on the surface of the semiconductor electrode were treated with the F-substituted organic compound. It can be seen that the solar cell of Comparative Example 1 having no F atom and the solar cell of Comparative Example 2 which was treated with the organic compound containing no F atom had better energy conversion efficiency. In particular, it is understood that the solar cells of Examples 1 to 4 using the alkoxysilane containing a fluorine atom can obtain high energy conversion efficiency.
[0067]
(Examples 9 to 13)
Instead of using a gel electrolyte, methylpropyl imidazolium iodide was added to t-butylpyridine at 0.58M, LiI at 0.5M, I₂Of Example 1 or Example 2 described above, except that an electrolyte solution containing 0.3 M and 10 wt% of water was used, and the type and adsorption method of the fluorine-substituted organic compound were changed as shown in Table 2 below. A dye-sensitized solar cell was manufactured in the same manner as described above.
[0068]
(Comparative Example 3)
A dye-sensitized solar cell was manufactured in the same manner as in Example 1 except that the electrolytic solution described in Example 9 was used instead of using the gel electrolyte, and that the treatment with the fluoroalkyl oligomer-substituted trimethoxysilane was not performed. did.
[0069]
(Comparative Example 2)
The n-type semiconductor electrode holding substrate after dye adsorption is immersed in a toluene solution in which methyltrimethoxysilane is dissolved, so that methyltrimethoxysilane is adsorbed on the surface of the semiconductor electrode, and the above-described procedure is performed instead of the gel electrolyte. A dye-sensitized solar cell was manufactured in the same manner as in Example 1 except that the electrolytic solution described in Example 9 was used.
[0070]
Regarding the obtained solar cells of Examples 9 to 13 and Comparative Examples 3 and 4, 100 mW / cm²The energy conversion efficiency when simulated sunlight was irradiated was measured, and the results are shown in Table 2 below.
[0071]
[Table 2]

[0072]
As is clear from Table 2, it can be understood that the solar cells of Examples 9 to 13 hardly hydrolyze the dye with water, and have a higher energy conversion efficiency than the solar cells of Comparative Examples 3 and 4. . In addition, when the solar cells of Examples 9 to 13 were heated at 80 ° C. for one week and the energy conversion efficiency was measured again, the efficiency hardly decreased. In particular, it is understood that the solar cells of Examples 9 to 10 using the alkoxysilane containing a fluorine atom can obtain high energy conversion efficiency.
[0073]
(Example 14)
An electrolyte composition obtained by adding 10 wt% of water to a solution of 0.3 M of iodine, 0.58 M of t-butylpyridine, and 0.5 M of LiI in 1-methyl-3-propylimidazolium iodide instead of the gel electrolyte Except for using, a dye-sensitized solar cell was manufactured in the same manner as in Example 2. When the energy conversion efficiency of this solar cell was measured under the same conditions as described above, it was 5.0%. In addition, heating at 80 ° C. for one week and measuring the energy conversion efficiency again showed almost no reduction in efficiency.
[0074]
(Example 15)
An electrolyte composition obtained by adding 55 wt% of water to a solution of 0.3 M of iodine, 0.58 M of t-butylpyridine, and 0.5 M of LiI in 1-methyl-3-propylimidazolium iodide instead of the gel electrolyte Except for using, a dye-sensitized solar cell was manufactured in the same manner as in Example 2. When the energy conversion efficiency of this solar cell was measured under the same conditions as described above, it was 1%. Furthermore, when this solar cell was heated at 80 ° C. for one week and the energy conversion efficiency was measured again, it was 0.9%.
[0075]
(Comparative Example 5)
A dye-sensitized solar cell was manufactured in the same manner as in Example 15 except that the treatment with the fluoroalkyl oligomer-substituted trimethoxysilane was not performed. When the energy conversion efficiency of this solar cell was measured under the same conditions as described above, it was 0.9%. Furthermore, when this solar cell was heated at 80 ° C. for one week and the energy conversion efficiency was measured again, the output was reduced to 0.1%.
[0076]
【The invention's effect】
As described in detail above, according to the present invention, it is possible to provide a dye-sensitized solar cell with improved energy conversion efficiency and a method for manufacturing the same.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating an example of a manufacturing process of a dye-sensitized solar cell according to the present invention.
FIG. 2 is a sectional view showing an example of a dye-sensitized solar cell according to the present invention.
[Explanation of symbols]
1: Glass substrate
2. Transparent conductive film
3: Fine particles of titanium oxide
4 ... Semiconductor electrode
5 ... conductive film
6: Counter substrate
7,10 ... epoxy resin
8 ... Injection nozzle
9 ... Electrolyte composition
11 ... incident light.

Claims (3)

In a dye-sensitized solar cell including a semiconductor electrode, a counter electrode, and an electrolyte composition,
At least a portion of the surface of the semiconductor electrode is composed of a fluorine atom-containing alkoxysilane, a fluorine atom-containing chlorosilane, a fluorine atom-containing silanol, a fluorine atom-containing pyridine, and a fluorine atom-containing imidazole. A dye-sensitized solar cell, wherein a film containing at least one organic compound selected from the group and a dye is formed. The alkoxysilane, the chlorosilane, and the silanol each have an alkyl group bonded to a Si atom and at least one hydrogen atom is substituted with a fluorine atom, and the pyridines and the imidazoles each have at least The dye-sensitized solar cell according to claim 1, wherein one hydrogen atom has an alkyl group substituted with a fluorine atom, or at least one hydrogen atom is substituted with a fluorine atom. A step of adsorbing the dye on the surface of the semiconductor electrode,
Immersing the semiconductor electrode in a solution containing an organic compound, or exposing the semiconductor electrode to a vapor atmosphere of an organic compound,
The organic compound is at least one selected from the group consisting of a fluorine atom-containing alkoxysilane, a fluorine atom-containing chlorosilane, a fluorine atom-containing silanol, a fluorine atom-containing pyridine, and a fluorine atom-containing imidazole. A method for producing a dye-sensitized solar cell, which is one type.

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