JP2018206904A - Photoelectrode for dye-sensitized solar cell and dye-sensitized solar cell using the same - Google Patents

Abstract

To provide a photoelectrode for use in dye-sensitized solar cell capable of improving photoelectric conversion efficiency for converting photovoltaic energy into electrical power, without using a large amount of nanoparticles of expensive metal such as gold.SOLUTION: A photoelectrode for dye-sensitized solar cell includes a glass substrate provided with a transparent conductive film 12 on one side, a metal oxide layer 13 provided on the side of the transparent conductive film 12 opposite to the glass substrate and composed of particulate metal oxide, a sensitization color material adsorbed to the surface of the metal oxide, and metal nanoparticles 15 in the metal oxide layer 13. Density of the metal nanoparticles 15 separated by a distance from the transparent conductive film 12 to the depth where the light of maximum adsorption wavelength of the sensitization color material 14 reaches is higher than that of other region in the metal oxide layer 13.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dye-sensitized solar cell photoelectrode obtained by adsorbing a sensitizing dye to a metal oxide and a dye-sensitized solar cell using the same.

  Regarding the dye-sensitized solar cell, a research group of Gratzel et al. Announced a solar energy conversion efficiency of 7.1% in 1991 (Non-patent Document 1), and in 1993 the group announced a conversion efficiency of 10%. In particular, it has become a technology that attracts worldwide attention (Non-Patent Document 2).

  The structure of the dye-sensitized solar cell announced by Gratzel et al. Is provided with an indium / tin based transparent conductive layer on the inside of a glass plate or transparent plastic sheet, and fine metal oxide such as titanium dioxide in the transparent conductive layer. And a red electrode such as an iodine solution is filled between a photoelectrode in which a sensitizing dye such as a ruthenium compound is adsorbed on the metal oxide and a counter electrode such as platinum or carbon.

  The above dye-sensitized solar cell has a feature that the manufacturing method is simple and the cost for manufacturing is low compared to the silicon-based solar cell using single crystal or polycrystalline silicon. Improvement of performance, such as improvement, has become an issue.

  As shown in Non-Patent Document 3, for high performance such as improvement of photoelectric conversion efficiency in dye-sensitized solar cells, light obtained by uniformly dispersing metal nanoparticles such as gold in fine particle metal oxides such as titanium dioxide Dye-sensitized solar cells using electrodes are known. This technology aims to improve photoelectric conversion efficiency by using surface plasmon resonance of metal nanoparticles such as gold to enhance light absorption and improve short circuit current.

B. O'regan, M.M. Graetzel, Nature (London, United Kingdom), 353, 737 (1991) M.M. K. Nazeeruddin, a. Kay, I.D. Rodicio, R.C. Humphry-Baker, E .; Mueller, P.M. Liska, N .; Vlachopoulos, M.M. Graetzel, Journal of the American Chemical Society, 115, 6382 (1993) Nahm C, Choi H, Kim J, Jung DR, Kim C, Moon J, Lee B, Park B. et al. Appl. Phys. Lett. 99: 253107 1-4. (2011)

  However, in the photoelectrode in Non-Patent Document 3 in which metal nanoparticles such as gold are uniformly dispersed in a fine particle metal oxide such as titanium dioxide, it is difficult to use in large quantities because gold is expensive. There is a need for more efficient photoelectrodes that take advantage of dye-sensitized solar cells that can be manufactured at low cost.

  Therefore, in the present invention, it is a photoelectrode used in a dye-sensitized solar cell, and has a photoelectric conversion efficiency for converting solar energy into electric power without using a large amount of expensive metal nanoparticles such as gold. It is an object to provide a photoelectrode that can be improved.

  [1] That is, the present invention includes a glass substrate provided with a transparent conductive film on one surface, and a particulate metal oxide provided on one surface of the transparent conductive film opposite to the glass substrate. A metal oxide layer, a sensitizing dye adsorbed on the surface of the metal oxide, metal nanoparticles in the metal oxide layer, and a maximum absorption wavelength of the sensitizing dye from the transparent conductive film. It is a photoelectrode for a dye-sensitized solar cell, characterized in that the density of the metal nanoparticles separated by a distance near the depth to which light reaches is higher than other regions in the metal oxide layer.

  [2] The dye enhancement according to [1], wherein the density of the metal nanoparticles 2 to 6 μm away from the transparent conductive film is higher than that of other regions in the metal oxide layer. It is a photoelectrode for a solar cell.

  [3] The dye according to [1] or [2], wherein the metal nanoparticles are at least one selected from gold, silver, and copper, and have a particle diameter of 10 to 200 nm. This is a photoelectrode for a sensitized solar cell.

  [4] The dye-sensitized solar cell photoelectrode according to any one of [1] to [3], wherein the sensitizing dye is a ruthenium bipyridine complex.

  [5] A dye-sensitized solar cell comprising the dye-sensitized solar cell photoelectrode according to any one of [1] to [4].

  In the dye-sensitized solar cell including the photoelectrode of the present invention, the photoelectric conversion efficiency for converting sunlight energy into electric power can be improved without using a large amount of expensive metal nanoparticles such as gold.

It is a conceptual diagram which shows the photoelectrode of this invention, and a dye-sensitized solar cell using the same. (A) TEM image for synthesized 20 nm diameter gold nanoparticles (b) TEM image for synthesized 40 nm diameter gold nanoparticles (c) TEM image for synthesized 60 nm diameter gold nanoparticles (d ) TEM image of 90 nm diameter gold nanoparticles synthesized. It is a graph which shows the light absorbency of the metal oxide layer (without metal nanoparticles, with a sensitizing dye) which consists of titanium oxide of various thickness with respect to the light of each wavelength. It is a graph which shows the light absorbency of the light of each wavelength with respect to various thickness of the metal oxide layer (without metal nanoparticles, with a sensitizing dye) which consists of titanium oxide.

  Hereinafter, embodiments related to the present invention will be described in detail. The expression representing the range includes the upper limit and the lower limit.

  The photoelectrode 1 which is the negative electrode of the dye-sensitized solar cell shown in FIG. 1 is produced as follows. That is, first, using a transparent conductive oxide such as indium tin oxide (ITO) on a transparent glass substrate 11 having a thickness of 0.1 to 10 mm, a transparent conductive film having a thickness of 100 to 600 nm is obtained by a method such as vacuum deposition, sputtering, or CVD. By forming the film 12, the glass substrate 11 provided with the transparent conductive film 12 is produced.

  Then, a solution in which a metal oxide having a particle diameter of 1 to 100 nm is dispersed on the transparent conductive film 12 is applied by a coating method such as screen printing, the solvent is removed by heating, and further heated to a high temperature. Then, the metal oxide layer 13 is prepared, and the metal nanoparticles 15 are similarly contained using the metal nanoparticles 15 in which the metal nanoparticles 15 are mixed with the metal oxide 15 and a solution in which the metal oxide is dispersed. A metal oxide layer 13 is also produced, and the metal oxide layer 13 is multilayered. In this way, the metal oxide layer 13 including the metal nanoparticles 15 dispersed in a layer shape substantially parallel to the transparent conductive film 12 is formed on a part of the multilayered metal oxide layer 13, and transparent conductive The metal oxide layer 13 having a thickness of 10 to 100 μm is formed on the conductive film 12 as a whole, and the density of the metal nanoparticles 15 is higher than that of other regions.

  And the metal oxide layer 13 in which the metal oxide layer 13 in which the metal nanoparticles 15 are contained in a part of the layer is formed, and the metal oxide layer 13 is immersed in a solution containing the sensitizing dye 14 in the glass substrate having the transparent conductive film. After that, the solvent is dried and removed, and the sensitizing dye 14 is adsorbed to the metal oxide layer 13, whereby the photoelectrode 1 which is the negative electrode of the dye-sensitized solar cell is produced.

This particulate metal oxide has a porous shape in which a plurality of metal oxides causing transition between band gaps are aggregated. The shape of each metal oxide is not limited to a spherical shape, and may be any shape such as a rod shape, a needle shape, or a cone shape. Examples of the metal oxide material include strontium titanate (SrTiO ₃ ), barium titanate (BaTiO ₃ ), titanium dioxide (TiO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), and magnesium oxide (MgO). ), Zinc oxide (ZnO), tungsten oxide (IV) (WO ₃ ), bismuth (III) oxide (Bi ₂ O ₃ ), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), Various metal oxides such as indium (III) oxide (In ₂ O ₃ ) and tin (IV) oxide (SnO ₂ ) are used. Of these, titanium dioxide is preferably used to improve photoelectric conversion efficiency. When titanium dioxide is used, the anatase type is more preferable as the crystal structure than the rutile type.

  The sensitizing dye 14 absorbs a specific wavelength of sunlight and enters an excited state, and functions as the sensitizing dye 14 that injects electrons into the particulate metal oxide adsorbed by the sensitizing dye 14. And as a metal contained in the sensitizing dye 14, transition metals, such as ruthenium, osmium, iron, copper, platinum, cobalt, rhenium, chromium, are used.

As such a sensitizing dye 14, cis-dithiocyano bis (4,4′-dicarboxy-2,2′-bipyridine) ruthenium; Ru (dcbpy) ₂ (NCS) ₂ ; N3, bis (tetrabutylammonium) [shis-di (Thiocyanato) -bis (2,2′-bipyridyl-4-carboxylate-4′-carboxylic acid) -ruthenium; N719, Ru (tctpy) ₂ (NCS) ₃ ; N714, Ru (dmipy) H (dcBip, H) _{(dcphenTBA (H)) 2 (} NCS) 2, cis-Ru (dcbiqH) 2 (NCS) 2 (TBA) ruthenium bipyridine complex such as _{2, cis-dithiocyano} bis ( , 4'-dicarboxy-2,2'-bipyridine ) osmium; Os (dcbpy) 2 (NCS) osmium bipyridine-based complex such as _{2, cis-dithiocyano bis (4,4'} -dicarboxy-2,2'-bipyridine) iron; iron bipyridine complex such as Fe (dcbpy) ₂ (NCS) ₂ , copper phenanthroline complex such as bis (2,9-di (4-carboxy) diphenyl-1,10-phenanthroline) copper, Pt (dcbpy) ₂ (L) ₂ Platinum quinoxaline complex such as [L: quinoxaline-2,3-dithiolate], rhenium pyridine complex such as Re (bpy) (CO) ₃ (ina), and the like.

  The metal nanoparticles 15 are metal particles having a nanometer (nm) size, and are preferably at least one selected from transition metals such as gold, silver, and copper. For example, gold nanoparticles are synthesized by the Turkevich method. Specifically, 100 ml of 0.01% by weight tetrachloride gold (III) acid aqueous solution was heated until boiling, and 3.5 ml of 1% by weight trisodium citrate dihydrate aqueous solution was added to the boiling water. Stir and continue to stir for 60 minutes while boiling. Then, gold having a particle diameter of 20 nm or less is obtained. Then, 6 ml of a gold suspension having a particle size of 20 nm or less as a seed was added to 100 ml of a boiled 0.01 wt% tetrachloride gold (III) acid aqueous solution, and 1 wt% trisodium citrate dihydrate. When 0.5 ml of an aqueous solution is added and stirred, gold having a particle size of 40 nm or less is obtained. Similarly, gold having a particle size of 60 nm or less or 90 nm or less is obtained. If gold having a desired particle size can be synthesized, the supernatant is removed after centrifugation at 1000 rpm for 20 minutes, 90% by volume ethanol water is added to the gold particles accumulated therein, and the gold particle suspension used in the dye-sensitized solar cell is added. Make a suspension. The gold nanoparticles thus synthesized are shown in FIG. Further, a tetraethyl orthosilicate solution and aqueous ammonia can be added to the obtained gold particles to produce gold particles having a silicon dioxide layer on the surface of the gold particles.

  The particle diameter of the metal nanoparticles 15 is preferably 10 to 200 nm, more preferably 20 to 90 nm, and most preferably 40 to 60 nm. When the particle diameter of the metal nanoparticle 15 is within this range, when the photoelectrode 1 including the metal oxide layer 13 including the metal nanoparticle 15 in a layer form is produced and a dye-sensitized solar cell is produced, the short-circuit current is reduced. Improve the conversion efficiency. The particle diameter of the metal nanoparticles 15 is measured by a field emission transmission electron microscope (TEM) (JEOL, JEM-2200FS).

  In the metal oxide layer 13, the metal nanoparticles 15 are separated from the transparent conductive film 12 by another distance near the depth at which the light having the maximum absorption wavelength of the sensitizing dye 14 reaches. 13 is preferably located higher than other regions in the region 13 and higher than other regions in the other metal oxide layer 13 at a position 2 to 6 μm away from the transparent conductive film 12. More preferably, it is located so as to be higher than other regions in the other metal oxide layer 13 at a position 3 to 5 μm away from the transparent conductive film 12. Most preferred. When the metal nanoparticles 15 are distributed in this range from the transparent conductive film 12 at a high density, the sensitizing action of the sensitizing dye 14 is maximized and the metal nanoparticles are dispersed by the light scattering effect of the metal nanoparticles. As the surface plasmon resonance due to the energy increases, the energy transition to the sensitizing dye 14 and the like increases, so that the short-circuit current is improved and the conversion efficiency is improved, and it is not necessary to add metal nanoparticles more than necessary. Therefore, the cost can be reduced. Further, if the metal nanoparticles 15 are separated from each other by the predetermined distance, a plurality of layers of the metal nanoparticles 15 can be provided to form a multilayer shape, or the metal nanoparticles 15 can be distributed within the predetermined distance range without being provided in layers. You can also.

In one metal oxide layer 13 containing the metal nanoparticles 15, the metal nanoparticles 15 are preferably contained at a density of 0.5 to ⁶ μg / cm ² . When the metal nanoparticles 15 are contained in this density range, the short circuit current is improved and the conversion efficiency is improved.

  In addition, it has a functional group (imidazolyl group, carboxyl group, phosphone group, etc.) that binds to the particulate metal oxide, does not cause desorption as a result of binding, and suppresses exposure of the electrode surface as a result of adsorption. Possible molecules can be used as additives. Specific examples include phosphonic acids having a long-chain alkyl group such as tert-butylpyridine, 1-methoxybenzimidazole, and decanephosphoric acid.

  When the dye-sensitized solar cell is manufactured, the positive electrode 3 as the counter electrode can be any conductive material as long as it is a conductive material. However, even an insulating material is conductive on the side facing the semiconductor electrode. If a layer is in place, it can be used. However, it is preferable to use an electrochemically stable substance for the counter electrode. Specifically, platinum, platinum black, carbon, conductive polymer, and the like can be given. The positive electrode 3 may be a transparent or opaque substrate such as a quartz glass substrate on which a film of the above substance is formed, or may be a platinum substrate.

  The electrolyte 2 disposed between the photoelectrode 1 and the positive electrode 3 is liquid, gel, or solid, and redox species such as iodine and iodide are in an aqueous solution or the redox species are dispersed. It is a gel or solid. Redox chemical species iodine and iodide such as lithium iodide, sodium iodide, potassium iodide and the like can be mixed. Further, it is preferable to further adjust the neutrality of the electrolyte 2 by adding lithium hydroxide, sodium hydroxide, or the like.

  In the case where the electrolyte 2 is in the form of a gel or a solid, the electrolyte 2 only needs to be in the form of a gel or a solid when manufactured as a dye-sensitized solar cell, and contains a liquid in the manufacturing process. Also good.

  Further, the electrolyte 2 can contain an ionic liquid. An ionic liquid is a salt that can exist in a liquid at a relatively low temperature of about 150 ° C. or less. The ionic liquid is a non-volatile organic solvent, volatilizes with time and does not lose its weight, and imparts a certain fluidity to the electrolyte 2. Furthermore, since the electrolyte 2 contains the ionic liquid, the contact area between the electrolyte 2 and titanium oxide is increased and the transfer of charges from the electrolyte 2 to titanium oxide is improved, so that the conversion efficiency is improved. Examples of the ionic liquid include 1,2-dimethyl-3-propylimidazolium iodide (DMPII), 1-methyl-3-butylimidazolium iodide (BMII), 1-ethyl-3-methylimidazolium iodide ( EMII), 1-octyl-3-methylimidazolium iodide (OMII), tetra-n-butylammonium iodide (TBAI) and the like are preferable.

  Hereinafter, embodiments of the present invention will be specifically described. In addition, this invention is not limited to the following embodiment.

(Reference Example 1)
[Confirmation of maximum absorption wavelength of sensitizing dye]
Paste containing fine particles of titanium oxide having a particle size of about 20 nm on the ITO film surface of glass (Part No .: 0052, manufactured by Geomatec) coated with an indium tin oxide film (ITO film) having a sheet resistance of 10 Ωsq ⁻¹ (Product number: PST-18NR, manufactured by JGC Catalysts & Chemicals Co., Ltd.) was applied by a screen printing method. And it annealed at 500 degreeC in nitrogen atmosphere for 30 minutes in the furnace, and obtained the metal oxide layer of the porous titanium oxide of 1.65 micrometer. Then, as a sensitizing dye, ruthenium dye N719 [di-tetrabutylammonium cis-dithiocyano bis (2,2′-bipyridyl-4,4′-dicboxylate) ruthenium (II)] is dissolved in absolute ethanol and the concentration is 3 × 10 ^{−. A 4} mol / L dye adsorption solution was prepared. The titanium oxide layer was immersed in this solution at 25 ° C. for 20 hours to adsorb the ruthenium dye. Then, the titanium oxide electrode was taken out from the N719 solution, washed with ethanol, and dried. Thus, the photoelectrode which does not contain a metal nanoparticle was produced. Moreover, the photoelectrode produced similarly was produced except having set the thickness of the metal oxide layer to 2.72 μm, 3.40 μm, 6.74 μm, 8.37 μm, 11.8 μm, and 15.3 μm. Using these photoelectrodes having different metal oxide layer thicknesses, the absorbance was measured with an ultraviolet-visible spectrophotometer (product number: CEP-2000, manufactured by Spectrometer Co., Ltd.). As shown in FIG. 3, the maximum absorption of N719, which is a sensitizing dye, was also observed near 520 nm in the thickness of the metal oxide layer. Note that absorption near 350 nm is due to titanium oxide.

(Reference Example 2)
[Confirmation of depth of arrival in metal oxide layer by light of maximum absorption wavelength of sensitizing dye]
Then, using the data of FIG. 3, the absorbance of light having wavelengths of 350 nm, 520 nm, and 650 nm with respect to various thicknesses of the metal oxide layer containing titanium oxide was plotted to create FIG.
As shown in FIG. 4, it can be seen that the light of 520 nm reaches a peak at around 4 μm from the transparent conductive film, and is less likely to be absorbed deeper than the metal oxide layer. The depth reached by the light having the maximum absorption wavelength was about 2 to 6 μm. Therefore, if the density of the metal nanoparticles is higher than other regions near the depth where the light having the maximum absorption wavelength of the sensitizing dye reaches from the transparent conductive film, surface plasmon resonance by the metal nanoparticles In addition, the optical path length is increased by light scattering by the metal nanoparticles, and it can be expected that gold nanoparticles can be utilized to the maximum.

Example 1
Paste containing fine particles of titanium oxide having a particle size of about 20 nm on the ITO film surface of glass (Part No .: 0052, manufactured by Geomatec) coated with an indium tin oxide film (ITO film) having a sheet resistance of 10 Ωsq ⁻¹ (Product number: PST-18NR, manufactured by JGC Catalysts & Chemicals Co., Ltd.) was applied by a screen printing method. Then, annealing was performed in a furnace at 450 ° C. for 15 minutes in a nitrogen atmosphere to obtain one metal oxide layer of 1.1 μm porous titanium oxide, and the same operation was performed once again. Two metal oxide layers were obtained. The area of the metal oxide layer is approximately 25 mm ² (5 mm × 5 mm). An aqueous solution of gold nanoparticles having a diameter of 40 nm is dropped onto the surface of the 2.2 μm metal oxide layer so as to be 2.7 μg / cm ^2, and is naturally dried, so that the gold nanoparticles are substantially parallel to the ITO film. It was dispersed in a layer form. Further, a metal oxide layer of porous titanium oxide was further laminated by the same method to obtain a metal oxide layer having an overall thickness of 6 μm. Finally, it was annealed at 500 ° C for 30 minutes.

Next, as a sensitizing dye, ruthenium dye N719 [di-tetrabutylammonium cis-dithiocyano bis (2,2′-bipyridyl-4,4′-dicboxylate) ruthenium (II)] is dissolved in absolute ethanol, and the concentration is 3 × 10. A solution for ^-4 mol / L dye adsorption was prepared. The titanium oxide layer was immersed in this solution at 25 ° C. for 20 hours to adsorb the ruthenium dye. Then, the titanium oxide electrode was taken out from the N719 solution, washed with ethanol, and dried. In this way, a photoelectrode was produced.

In order to prepare a positive electrode as a counter electrode of the photoelectrode, a hole having a diameter of 0.9 mm is formed in glass (product number: No.0052, manufactured by Geomatec) coated with an indium tin oxide film (ITO film) having a sheet resistance of 10 Ωsq ^−1. A few drops of an ethanol solution in which 2 mg of hexachloroplatinic (IV) acid hexahydrate was dissolved in 1 ml of ethanol was dropped on the ITO film surface and heated at 400 ° C. for 30 minutes. In this way, a positive electrode as a platinum electrode was obtained.

  Using a polyimide film (product number: Himilan film, manufactured by Pexel Technologies) as a spacer between the photoelectrode and the positive electrode, the photoelectrode and the positive electrode are joined by heating and melting on a hot plate to produce an open cell. did. And under reduced pressure, 0.05M iodine, 0.05M lithium iodide, 0.6M 1,2-dimethyl-3-propylimidazolium (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) from the hole opened in the positive electrode. The positive electrode was covered with a polyimide film (product number: Himilan film, manufactured by Pexel Technologies), covered with a cover glass, and the polyimide film was heated and melted and sealed. In this way, a typical sandwich type dye-sensitized solar cell was produced.

(Example 2)
A dye-sensitized solar cell was produced in the same manner as in Example 1 except that gold nanoparticles were dispersed in a layer shape substantially parallel to the ITO film at a position of 3.3 μm from the ITO film.

Example 3
A dye-sensitized solar cell was produced in the same manner as in Example 1 except that gold nanoparticles were dispersed in a layer shape substantially parallel to the ITO film at a position of 4.4 μm from the ITO film.
(Example 4)
A dye-sensitized solar cell was produced in the same manner as in Example 1, except that gold nanoparticles were dispersed in a layer substantially parallel to the ITO film at a position of 5.5 μm from the ITO film.

(Comparative Example 1)
A dye-sensitized solar cell was produced in the same manner as in Example 1 except that gold nanoparticles were not used.

(Comparative Example 2)
A dye-sensitized solar cell was produced in the same manner as in Example 1 except that gold nanoparticles were dispersed in a layer shape substantially parallel to the ITO film at a position 1.1 μm from the ITO film.

The dye-sensitized solar cells obtained in Examples 1 to 4 and Comparative Examples 1 and 2 were irradiated with xenon light (AM1.5, 100 mWcm ⁻² ), and Desktop EasyEXPERT software (V.4.0) manufactured by Agilent. The current-voltage characteristics were measured using a semiconductor parameter analyzer (product number: HP41563) manufactured by Hewlett-Packard. From the obtained current-voltage curve, the short circuit current (Jsc), the open circuit voltage (Voc), the FF (fill factor) and the photoelectric conversion efficiency (η) of the battery were calculated from the formula η = Jsc × Voc × FF. .

  Table 1 shows a list of electrical characteristics of the dye-sensitized solar cells obtained in Examples 1-4 and Comparative Examples 1-2.

  From the result of Table 1, in Examples 1-4 which arrange | position gold nanoparticles in the position 2.2-5.5 micrometers away from the ITO film | membrane, it separated 1.1 micrometers from the comparative example 1 and ITO film | membrane which did not add these. It was found that the short-circuit current was improved as compared with Comparative Example 2 in which the gold nanoparticles were arranged at the positions, and as a result, the photoelectric conversion efficiency was also improved.

(Example 5)
An aqueous solution of gold nanoparticles with a diameter of 40 nm was dropped at a position of 3.6 μm from the ITO film so as to be 0.65 μg / cm ^2, and the gold nanoparticles were dispersed in a layer shape substantially parallel to the ITO film. Except for the above, a dye-sensitized solar cell was produced in the same manner as in Example 1.

(Example 6)
Dye-sensitized sun as in Example 5 except that an aqueous solution of gold nanoparticles was dropped to 1.3 μg / cm ² and gold nanoparticles were dispersed in a layer substantially parallel to the ITO film. A battery was produced.

(Example 7)
Dye-sensitized sun as in Example 5, except that an aqueous solution of gold nanoparticles was dropped to 2.7 μg / cm ² and the gold nanoparticles were dispersed in a layer substantially parallel to the ITO film. A battery was produced.

(Example 8)
Dye-sensitized sun as in Example 5 except that an aqueous solution of gold nanoparticles was dropped to 5.4 μg / cm ² and gold nanoparticles were dispersed in a layer substantially parallel to the ITO film. A battery was produced.

(Comparative Example 3)
A dye-sensitized solar cell was produced in the same manner as in Example 5 except that gold nanoparticles were not used.

  Table 2 shows a list of electrical characteristics of the dye-sensitized solar cells obtained in Examples 5 to 8 and Comparative Example 3 in the same manner as in Examples 1 to 4 and Comparative Examples 1 and 2.

From the results of Table 2, in Examples 5 to 8 where the density of the gold nanoparticles is 0.65 to 5.4 μg / cm ² , the short-circuit current is improved as compared with Comparative Example 3 in which these were not added. As a result, the photoelectric conversion efficiency was also improved.

1 ... Photoelectrode (negative electrode)
DESCRIPTION OF SYMBOLS 11 ... Glass substrate 12 ... Transparent conductive film 13 ... Metal oxide layer 14 ... Sensitizing dye 15 ... Metal nanoparticle 2 ... Electrolyte 3 ... Positive electrode

Claims (5)

A glass substrate provided with a transparent conductive film on one surface;
A metal oxide layer made of particulate metal oxide provided on one surface of the transparent conductive film opposite to the glass substrate;
A sensitizing dye adsorbed on the surface of the metal oxide;
Comprising metal nanoparticles in the metal oxide layer;
The density of the metal nanoparticles separated from the transparent conductive film by a distance in the vicinity of the depth at which light having the maximum absorption wavelength of the sensitizing dye reaches is higher than other regions in the metal oxide layer. A photoelectrode for a dye-sensitized solar cell. 2. The dye-sensitized solar cell photoelectrode according to claim 1, wherein the density of the metal nanoparticles 2 to 6 μm away from the transparent conductive film is higher than that of other regions in the metal oxide layer. . 3. The dye-sensitized solar cell photoelectrode according to claim 1, wherein the metal nanoparticles are at least one selected from gold, silver, and copper and have a particle diameter of 10 to 200 nm. . 4. The dye-sensitized solar cell photoelectrode according to claim 1, wherein the sensitizing dye is a ruthenium bipyridine complex. A dye-sensitized solar cell comprising the photoelectrode for a dye-sensitized solar cell according to any one of claims 1 to 4.

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