JP2007227062A - Photoelectric converter, manufacturing method thereof, and photovoltaic generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric converter having high photoelectric conversion efficiency that can be composed of a small number of materials easily. <P>SOLUTION: In the photoelectric converter 1, porous oxide semiconductor layers 3, 4 adsorbing a coloring matter, and a permeation layer 7 and a counter electrode layer 8 that permeate an electrolyte solution and hold the permeated solution, are formed successively on a conductive substrate 2. The arithmetic mean roughness of the surface of the porous oxide semiconductor layer 3 at a light incident side or the surface of a rupture surface is smaller than that of the surface of the porous oxide semiconductor layer 4 at a light emission side or the surface of the rupture surface. Then, the thickness of the porous oxide semiconductor layer 3 at a light incident side is larger than that of the porous oxide semiconductor layer 4 at a light emission side. Since the hole of the permeation layer 7 can be set so that the electrolyte solution can be permeated independently of the size of the vacancy of the porous oxide semiconductor layers 3, 4, the electrolyte solution can be injected after forming a laminate, thus thinning the laminate containing the electrolyte solution where light is scattered appropriately. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dye-sensitized photoelectric conversion device such as a solar cell or a light receiving element excellent in photoelectric conversion efficiency, a manufacturing method thereof, and a photovoltaic device.

  Conventionally, a dye-sensitized solar cell, which is a type of photoelectric conversion device, does not require a vacuum device for its production, so it is considered to be a low-cost, low-environmental load-type solar cell, and is actively researched and developed. Has been done.

  This dye-sensitized solar cell is usually provided with a porous titanium oxide layer having a thickness of about 10 μm obtained by sintering fine particles of titanium oxide having an average particle size of about 20 nm on a conductive glass substrate at about 450 ° C. A photoactive electrode substrate in which a single molecule of a dye is adsorbed on the surface of the titanium oxide particles of the porous titanium oxide layer, and a counter electrode substrate in which a platinum or carbon counter electrode layer is formed on a conductive glass substrate The porous titanium oxide layer and the counter electrode layer are opposed to each other, a frame-shaped thermoplastic resin sheet is used as a spacer and sealing material, and both substrates are bonded by hot pressing, and iodine / iodide is interposed between these substrates. It is obtained by injecting an electrolyte solution containing a redox couple. In the solar cell thus obtained, the dye adsorbed on the porous titanium oxide layer as the porous oxide semiconductor layer absorbs the irradiated light energy, and the generated electrons move to the porous oxide semiconductor layer. Then, the electrolyte is transferred as ions from the counter electrode layer via an external load circuit and returned to the pigment, thereby being taken out as electric energy (see Non-Patent Document 1 below).

  However, since this dye-sensitized solar cell normally uses a single-layer porous oxide semiconductor layer, the amount of light absorption contributing to photoelectric conversion is small and the amount of light transmission is large. , Also referred to as conversion efficiency). Therefore, the configuration of Patent Document 1 in which a light-reflecting particle layer is provided on the back surface of the porous oxide semiconductor layer, the porous oxide semiconductor layer having a plurality of layers, each having a different fine particle size, There are configurations of Patent Documents 2 and 3 in which large light scattering particles are mixed in a physical semiconductor layer so as to function as a scattering layer.

  In Patent Document 1, an electrode is provided on the back surface of a glass substrate, a light absorbing particle layer in which semiconductor fine particles adsorbing a dye are deposited is formed on the lower surface of the electrode, and the lower surface of the electrode includes the light absorbing particle layer. In the dye-sensitized solar cell in which the electrolyte portion is provided and the counter electrode is provided on the lower surface of the electrolyte portion, a highly refractive material thin film is provided between the electrode and the light-absorbing particle layer, and the light-absorbing particles A dye-sensitized solar cell is described in which a light-reflecting particle layer in which high refractive material particles having a controlled particle size are deposited is provided on the lower surface of the layer. With this configuration, most of the energy of light that has been transmitted through the light-absorbing particle layer composed of semiconductor fine particles in the conventional structure can be absorbed and confined in this light-absorbing particle layer. The output current can be increased.

  Patent Document 2 discloses a transparent conductor layer, an n-type oxide semiconductor electrode formed by laminating fine particles, a dye adsorbed on the n-type oxide semiconductor electrode, and a charge transport layer in contact with the dye And a counter electrode in contact with the charge transport layer, the photoelectric conversion element having a larger average particle size of the fine particles on the charge transport layer side than the average particle size of the fine particles in the vicinity of the transparent conductor layer. Are listed. The average particle size of the fine particles near the transparent conductor layer is 5 to 50 nm, and the average particle size of the fine particles near the charge transport layer is 30 to 500 nm. Further, since it is necessary to make the light incident on the transparent conductor layer side without scattering, it is desirable that the particle diameter of the fine particles forming the n-type oxide semiconductor electrode be as small as possible. On the other hand, on the charge transport layer side, it is desirable that the pore diameter inside the n-type oxide semiconductor electrode, which is a porous body, is as large as possible so that ions as charge carriers can easily diffuse to the vicinity of the dye. With this configuration, more light can be absorbed by the complex dye, and the diffusion of charge carriers in the charge transport layer can be facilitated, resulting in an increase in energy conversion efficiency.

  The photoelectric conversion element of Patent Document 3 is a photoelectric conversion element having at least a layer of a semiconductor fine particle film on which a dye is adsorbed and a conductive support, and the layer of the semiconductor fine particle film is composed of a plurality of layers having different light scattering properties. A photoelectric conversion element in which a layer having the lowest light scattering property is disposed on the light incident side. Further, the layer having low light scattering property is composed of semiconductor fine particles having an average particle diameter of 5 to 50 nm, and the layer having high light scattering property contains at least semiconductor fine particles having an average particle size of 100 to 500 nm and has a medium light scattering property. Contains a mixture of semiconductor fine particles having an average particle diameter of 100 to 500 nm and semiconductor fine particles having an average particle diameter of 5 to 50 nm.

  In Patent Document 3, the light-incident side has a low light scattering property and a light scattering property becomes higher as the light travels than in the case where the photosensitive layer has a uniform single layer structure in the film thickness direction. In the case of, the light capture rate is higher and the conversion efficiency is higher.

  The light scattering property of the photosensitive layer can be adjusted by the type, particle diameter, porosity, or void size of the semiconductor fine particles used. Among these, it is preferable to adjust by the particle diameter of the semiconductor fine particles.

  Further, when the photosensitive layer has a two-layer structure of a low scattering layer and a high scattering layer, it is preferable to mix two or more kinds of fine particles as constituents of the high scattering layer rather than using a single semiconductor fine particle. Specifically, the high scattering layer is particularly preferably a mixture of semiconductor fine particles having an average particle diameter of 5 to 50 nm and semiconductor fine particles having an average particle diameter of 100 to 500 nm. At this time, the content of the larger semiconductor fine particles is preferably 10 to 90% by weight, and more preferably 10 to 50% by weight.

  Furthermore, in the case of a three-layer configuration of a low scattering layer, a medium scattering layer, and a high scattering layer, it is preferable that two or more kinds of fine particles are mixed in the middle scattering layer rather than using a single semiconductor fine particle. Specifically, the medium scattering layer is particularly preferably a mixture of semiconductor fine particles having an average particle diameter of 5 to 50 nm and semiconductor fine particles having an average particle diameter of 100 to 500 nm. At this time, the content of the larger semiconductor fine particles is preferably 5 to 70% by weight, more preferably 10 to 50% by weight.

  Further, in the case of four or more layers, a composition in which the light scattering rate increases from the low light scattering layer side toward the high light scattering layer is desirable. The high scattering layer may be a single semiconductor fine particle having an average particle diameter of 100 to 500 nm or a mixture of two or more kinds of semiconductor fine particles. When the high scattering layer is composed of a mixture of semiconductor fine particles having an average particle diameter of 5 to 50 nm and semiconductor fine particles having an average particle diameter of 100 to 500 nm, the mixing ratio is such that the content of the larger semiconductor fine particles is 30 to 100% by weight. It is preferable that it is 50 to 100 weight%. Moreover, the content rate of the larger semiconductor particle is larger than that of the middle scattering layer.

The sensitizing dye used in the photosensitive layer can be used in combination or mixed with two or more kinds of dyes in order to make the wavelength range of photoelectric conversion as wide as possible and increase the conversion efficiency. In this case, the dye to be used or mixed and the ratio thereof can be selected so as to match the wavelength range and intensity distribution of the target light source. Patent Document 3 describes that a dye-sensitized photoelectric conversion element having improved conversion efficiency than the conventional one is obtained.
JP-A-10-255863 JP 2001-93591 A JP 2002-222968 A Published by Information Technology Co., Ltd. “Frontiers and Future Prospects of Dye-Sensitized Solar Cells and Solar Cells” P26-P27

  When a single porous oxide semiconductor layer is used as in a conventional dye-sensitized solar cell, there is a problem in that light use efficiency is low and high conversion efficiency cannot be obtained. Therefore, the configuration of Patent Document 1 in which a light-reflecting particle layer is provided on the back surface of the porous oxide semiconductor layer, a plurality of porous oxide semiconductor layers having different fine particle sizes, Although there existed the structure of the patent documents 2 and 3 which mixed the large light-scattering particle | grains with the oxide semiconductor layer and made it function also as a scattering layer, there existed the following problems, respectively.

  The solar cell of Patent Document 1 has the following problems. The light reflecting particle layer is composed of high refractive material particles made of, for example, titanium oxide (rutile) having a particle size of about 200 to 500 nm. The thickness of the light reflecting particle layer is preferably about 5 to 10 μm. Thus, it is difficult to sinter particles having such a large particle size at about 500 ° C., film formation cannot be performed, and the resistance of the conductive path is large, so that the current from the dye cannot be taken out efficiently. Further, when the temperature is raised for sintering, the electrical resistance of the electrode and the transparent conductive layer is increased, and the conversion efficiency is lowered. In addition, since the particle size of the light reflecting particle layer is an order of magnitude larger than the particle size of the light absorbing particle layer, the surface area of the particles becomes 1/100, so the amount of adsorbed dye is extremely small and hardly contributes to the improvement of the conversion efficiency. . In addition, providing a light-reflecting particle layer thin film made of highly refractive material particles complicates the manufacturing process and increases the cost.

  The photoelectric conversion device of Patent Document 2 has the following problems. The average particle size of the fine particles in the vicinity of the transparent conductor layer is 5 to 50 nm, and the average particle size of the fine particles in the vicinity of the charge transport layer is 30 to 500 nm, which is larger. It is difficult to sinter at about 0 ° C., a film cannot be formed, and the resistance of the conductive path is so large that the current from the dye cannot be taken out efficiently. Further, when the temperature is raised for sintering, the electrical resistance of the electrode and the transparent conductor layer is increased, and the conversion efficiency is lowered. In addition, when fine particles with a large particle size are mixed with fine particles with a small particle size, dispersion becomes difficult and the paste cannot be prepared well, and coating for film formation becomes difficult. Further, since the particle size of the light reflecting particle layer is an order of magnitude larger than the particle size of the light absorbing particle layer, the surface area of the particles becomes 1/100, the amount of adsorbed dye is extremely small, and hardly contributes to the improvement of the conversion efficiency. In addition, it is not possible to photoelectrically convert light in a wide absorption wavelength range with one kind of dye.

  In the photoelectric conversion element of Patent Document 3, the light scattering property of the photosensitive layer can be adjusted by the type, particle diameter, porosity or void size of the semiconductor fine particles to be used. However, there are the following problems. That is, preparing a particle having a large particle size such as semiconductor fine particles having an average particle size of 100 to 500 nm as a paste is difficult to prepare the paste because the dispersibility is lowered and the particles are likely to aggregate.

  In addition, it is difficult to sinter particles having a large particle size, such as semiconductor fine particles having an average particle size of 100 to 500 nm, at about 500 ° C., film formation is impossible, the resistance of the conductive path is large, and the current from the dye Cannot be taken out efficiently. Further, when the temperature is raised for sintering, the electrical resistance of the electrode and the transparent conductive layer is increased, and the conversion efficiency is lowered. Further, since the particle size of the high light scattering layer is one order of magnitude larger than the particle size of the low light scattering layer, the surface area of the particles is 1/100, the amount of adsorbed dye is extremely small, and hardly contributes to the improvement of the conversion efficiency. These problems are slightly reduced by mixing semiconductor fine particles having an average particle diameter of 5 to 50 nm and semiconductor fine particles having an average particle diameter of 100 to 500 nm, but these problems are not completely solved.

  Therefore, the present invention has been completed in view of the above problems in the prior art, and the object thereof is as follows.

(1) When light scattering property is imparted to the light emitting side porous oxide semiconductor layer, light incident is performed without using scattering particles having an average particle size larger than that of the semiconductor fine particles of the light incident side porous oxide semiconductor layer. The above-described various problems are solved by using semiconductor fine particles having the same average particle diameter as the semiconductor fine particles of the porous oxide semiconductor layer on the light emitting side for the porous oxide semiconductor layer on the light emitting side.

(2) Even when semiconductor fine particles having a small average particle diameter are used in the porous oxide semiconductor layer on the light emitting side, light scattering properties can be imparted to the porous oxide semiconductor layer on the light emitting side.

(3) The firing temperature can be surely fired at the same low temperature in the porous oxide semiconductor layer on the light incident side and the porous oxide semiconductor layer on the light exit side.

(4) To increase the productivity and reliability of the porous oxide semiconductor layer on the light emitting side, to ensure the conductive path, and to increase the conversion efficiency.

(5) Even when the light emitting side porous oxide semiconductor layer is formed, the electrical resistance of the electrode and the transparent conductive layer should not be increased.

(6) The porous oxide semiconductor layer on the light emitting side is made of a porous body having sufficient porosity, and has a large surface area, thereby increasing the amount of dye adsorbed and converting light on the longer wavelength side. To contribute to efficiency.

(7) Increasing the film thickness of the porous oxide semiconductor layer on the light incident side with high light transmittance, increasing the adsorption amount of the dye to increase the conversion efficiency, and porous oxidation on the light emitting side with high light reflectivity Reducing the electrical resistance of the porous oxide semiconductor layer by reducing the thickness of the physical semiconductor layer.

(8) A porous oxide semiconductor layer that can impart light scattering properties to a light emitting side porous oxide semiconductor layer even if semiconductor fine particles having a small average particle diameter are used in the light emitting side porous oxide semiconductor layer Providing a manufacturing method.

(9) As a monolithic laminated structure in which each layer is laminated on a single conductive substrate, a thin and light photoelectric conversion device that can be easily configured with a small number of components.

(10) After forming a laminate having an integral laminate structure, the dye is adsorbed to the porous oxide semiconductor layer through the permeation layer, and the electrolyte solution is permeated into the laminate through the permeation layer. To prevent deterioration of the dye and electrolyte due to heat treatment during the formation of the counter electrode layer after the dye and electrolyte are injected into the substrate, and to increase the conversion efficiency.

  That is, in summary, an object of the present invention is to provide a photoelectric conversion device with high photoelectric conversion efficiency that can be easily configured with a small number of components.

  The photoelectric conversion device of the present invention includes a porous oxide semiconductor layer that adsorbs a dye and contains an electrolyte on a conductive substrate, a permeation layer and a counter electrode layer in which the electrolyte solution permeates and the permeated solution is retained. The porous oxide semiconductor layer is formed by laminating a plurality of layers, and the arithmetic average roughness of the surface of the porous oxide semiconductor layer on the light incident side or the surface of the fracture surface is light. The thickness of the porous oxide semiconductor layer on the light incident side is smaller than the arithmetic mean roughness of the surface of the porous oxide semiconductor layer on the emission side or the surface of the fracture surface, and the porous oxide semiconductor layer on the light emission side It is characterized by being thicker than the thickness.

  In the photoelectric conversion device of the present invention, preferably, the arithmetic average roughness of the surface of the permeation layer or the surface of the fracture surface is larger than the arithmetic average roughness of the surface of the porous oxide semiconductor layer or the surface of the fracture surface. It is characterized by.

  In the photoelectric conversion device of the present invention, it is preferable that the permeation layer is made of a fired body obtained by firing at least one of insulator particles and oxide semiconductor particles.

  The photoelectric conversion device of the present invention is preferably characterized in that the permeation layer is made of a fired body obtained by firing at least one of aluminum oxide particles and titanium oxide particles.

  Moreover, the photoelectric conversion device of the present invention preferably covers the upper surface and the side surface of the laminate in which the porous oxide semiconductor layer, the permeation layer, and the counter electrode layer are sequentially formed on the conductive substrate. A sealing member for sealing is formed.

  In the photoelectric conversion device of the present invention, preferably, the porous oxide semiconductor layer formed by laminating a plurality of layers is formed of a sintered body of oxide semiconductor fine particles, and the porous oxide semiconductor layer on the light emitting side is The average particle size of the sintered particles of the oxide semiconductor fine particles is larger than the average particle size of the sintered particles of the oxide semiconductor fine particles forming the porous oxide semiconductor layer on the light incident side. .

  The first manufacturing method of the photoelectric conversion device of the present invention is a porous oxidation comprising a sintered body of oxide semiconductor fine particles formed by laminating a plurality of layers, which adsorbs a dye and contains an electrolyte on a conductive substrate. A method for producing a dye-sensitized photoelectric conversion device in which a semiconductor layer, an infiltration layer in which an electrolyte solution permeates and the infiltrated solution is retained and a counter electrode layer are sequentially formed, wherein a plurality of layers are laminated The average particle diameter of the primary particles before sintering of the oxide semiconductor fine particles constituting each layer of the porous oxide semiconductor layer is the same, and the porous oxide semiconductor layer on the light incident side has a dispersed phase as the dispersion phase. A colloidal liquid paste in which a dispersion medium is a liquid and is a primary particle of oxide semiconductor fine particles is applied and baked, and the porous oxide semiconductor layer on the light emitting side is formed into a gas as a dispersion medium in the liquid paste. D with The porous oxide semiconductor layer and the osmotic layer are formed on the conductive substrate after the osmotic layer is formed on the porous oxide semiconductor layer. The electrolyte solution is permeated through the permeation layer of the laminate.

  Further, the second method for producing the photoelectric conversion device of the present invention is a porous structure comprising a sintered body of oxide semiconductor fine particles formed by laminating a plurality of layers, which adsorbs a dye and contains an electrolyte on a conductive substrate. A method of manufacturing a dye-sensitized photoelectric conversion device in which a porous oxide semiconductor layer, an electrolyte solution permeates and a permeation layer that retains the permeated solution and a counter electrode layer are sequentially formed, wherein a plurality of layers are laminated The average particle diameter of primary particles before sintering of the oxide semiconductor fine particles constituting each of the porous oxide semiconductor layers is the same, and the porous oxide semiconductor layer on the light incident side is dispersed in a dispersed phase. Is formed by applying and baking a colloidal liquid paste in which the dispersion medium is a liquid and is a primary particle of the oxide semiconductor fine particles, and the porous oxide semiconductor layer on the light emission side is dispersed in the liquid paste. As organic resin A liquid paste to which particles are added is applied and baked, and then the permeation layer is formed on the porous oxide semiconductor layer, and then the porous oxide semiconductor layer and the permeation are formed on the conductive substrate. The electrolyte solution is infiltrated through the infiltration layer of the laminate formed with the layers.

  The third method for producing a photoelectric conversion device according to the present invention is a porous structure comprising a sintered body of oxide semiconductor fine particles formed by laminating a plurality of layers, which adsorbs a dye and contains an electrolyte on a conductive substrate. A method of manufacturing a dye-sensitized photoelectric conversion device in which a porous oxide semiconductor layer, an electrolyte solution permeates and a permeation layer that retains the permeated solution and a counter electrode layer are sequentially formed, wherein a plurality of layers are laminated The average particle diameter of primary particles before sintering of the oxide semiconductor fine particles constituting each of the porous oxide semiconductor layers is the same, and the porous oxide semiconductor layer on the light incident side is dispersed in a dispersed phase. Is formed by applying and baking a colloidal liquid paste in which the dispersion medium is a liquid and is a primary particle of the oxide semiconductor fine particles, and the porous oxide semiconductor layer on the light emission side is dispersed in the liquid paste. As organic resin Applying and firing an aerosol to which gas is added as a dispersion medium and baking, and then forming the permeation layer on the porous oxide semiconductor layer, and then forming the porous on the conductive substrate The electrolyte solution is allowed to permeate through the permeation layer of the laminate including the oxide semiconductor layer and the permeation layer.

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

  According to the photoelectric conversion device of the present invention, a porous oxide semiconductor layer that adsorbs a dye and contains an electrolyte on a conductive substrate, a permeation layer in which the electrolyte solution permeates and the permeated solution is retained, and The counter electrode layer is sequentially formed, and the porous oxide semiconductor layer is formed by laminating a plurality of layers, and the arithmetic average roughness of the surface of the porous oxide semiconductor layer on the light incident side or the surface of the fracture surface is light. The arithmetic average roughness of the surface of the porous oxide semiconductor layer on the emission side or the surface of the fracture surface is smaller than the thickness of the porous oxide semiconductor layer on the light emission side. Therefore, it is possible to uniformly and quickly infiltrate the electrolyte solution into the laminate through the permeation layer after forming a thin monolithic laminate having the counter electrode layer integrally laminated on the permeation layer. it can. Therefore, it is possible to prevent the deterioration of the dye and the electrolyte due to the heat treatment at the time of forming the counter electrode layer after injecting the dye and the electrolyte as in the conventional case, and as a result, the conversion efficiency can be increased.

  Further, since the permeation layer holds the permeated electrolyte solution with, for example, surface tension, the permeated solution can be prevented from leaking outside. As a result, since only a necessary amount of the electrolyte solution can be permeated, a photoelectric conversion device that can be manufactured at low cost is obtained.

  In addition, even if the size of the pores included in the porous oxide semiconductor layer and the size of the pores depending on the arithmetic average roughness such as the surface of the porous oxide semiconductor layer is small, Regardless of the size of the pores, the electrolyte solution can be distributed uniformly and uniformly throughout the porous oxide semiconductor layer through the permeation layer.

  In addition, since it is possible to have an integrated laminated structure in which each layer is laminated on a single conductive substrate, a counter electrode layer side substrate is not required, and a thin and light photoelectric conversion that can be easily configured with few components. It becomes a device.

  In addition, since the penetration layer can ensure electrical insulation between the counter electrode layer formed on the porous layer and the porous oxide semiconductor layer, an electrical short circuit between the counter electrode layer and the porous oxide semiconductor layer is prevented. Therefore, characteristics suitable for a charge conductive photoelectric conversion device can be obtained.

  Moreover, the porous oxide semiconductor layer on the light incident side scatters and confines short wavelength light (400 to 600 nm) well, but transmits long wavelength light (600 to 900 nm) well, and transmits long wavelength light. Because it is easy to do, it can be formed thick. Therefore, the dye adsorbed (supported) by the porous oxide semiconductor layer on the light incident side absorbs short-wavelength light well, and since the arithmetic mean roughness is small, the surface area becomes large and the amount of dye adsorbed increases. , The photocurrent from the dye can be increased.

  The porous oxide semiconductor layer on the light emitting side scatters and confines long-wavelength light inside thereof and can be formed thin, so that the resistance of the conductive path can be reduced. Therefore, long wavelength light is well absorbed by the dye adsorbed on the porous oxide semiconductor layer on the light emitting side, and the photocurrent from the dye is increased, and the current from the dye can be efficiently extracted with low resistance. .

  Further, according to the photoelectric conversion device of the present invention, when the arithmetic average roughness of the surface of the permeation layer or the surface of the fracture surface is larger than the arithmetic average roughness of the surface of the porous oxide semiconductor layer or the surface of the fracture surface, In the layer, the average particle size of the fine particles constituting the layer is larger than the average particle size of the porous oxide semiconductor layer, and in this case, the pores in the permeation layer become larger, so the inside of the permeation layer adjacent to the counter electrode layer Therefore, more electrolyte can be present, the electrical resistance due to the electrolyte contained in the permeation layer is reduced, and the conversion efficiency can be increased.

  According to the photoelectric conversion device of the present invention, when the osmotic layer is composed of a fired body obtained by firing at least one of the insulator particles and the oxide semiconductor particles, the osmotic layer fixes the porous oxide semiconductor layer. Thus, the photoelectric conversion device can be configured with a single substrate without bonding the two substrates.

  According to the photoelectric conversion device of the present invention, in the configuration in which at least one of the insulator particles and the oxide semiconductor particles is fired, the permeation layer is made of a fired body obtained by firing at least one of the aluminum oxide particles and the titanium oxide particles. Sometimes, the adhesion between the osmotic layer and the porous oxide semiconductor layer can be improved, and the conversion efficiency and reliability can be improved.

  In addition, according to the photoelectric conversion device of the present invention, the sealing member for sealing the electrolyte is formed covering the upper surface and the side surface of the laminate formed by forming the porous oxide semiconductor layer and the permeation layer on the conductive substrate. In this case, it is possible to ensure the reliability by suppressing the deterioration due to the contamination of the dye and the electrolyte from the outside air.

  Further, according to the photoelectric conversion device of the present invention, the porous oxide semiconductor layer formed by laminating a plurality of layers is composed of a sintered body of oxide semiconductor fine particles, and the oxidation forming the porous oxide semiconductor layer on the light emitting side. When the average particle size of the sintered particles of the oxide semiconductor particles is larger than the average particle size of the sintered particles of the oxide semiconductor particles forming the porous oxide semiconductor layer on the light incident side, the porous oxide on the light incident side The semiconductor layer scatters and confines short-wavelength light well but transmits long-wavelength light well, and can be formed thick because long-wavelength light is easily transmitted. Therefore, the dye adsorbed by the porous oxide semiconductor layer on the light incident side absorbs short-wavelength light well, and since the arithmetic mean roughness is small, the surface area is increased, and the amount of adsorbed dye is increased. The photoelectric conversion device can increase the photocurrent.

  According to the first method for producing a photoelectric conversion device of the present invention, a porous body comprising a sintered body of oxide semiconductor fine particles comprising a plurality of layers laminated to adsorb a dye and contain an electrolyte on a conductive substrate. A method of manufacturing a dye-sensitized photoelectric conversion device in which a porous oxide semiconductor layer, an electrolyte solution permeates and a permeation layer that retains the permeated solution and a counter electrode layer are sequentially formed, wherein a plurality of layers are laminated The average particle diameter of the primary particles before sintering of the oxide semiconductor fine particles constituting each layer of the porous oxide semiconductor layer is the same, and the porous oxide semiconductor layer on the light incident side is oxidized by the dispersed phase. The colloidal liquid paste, which is the primary particle of the solid semiconductor particle and the dispersion medium is a liquid, is applied and fired, and the porous oxide semiconductor layer on the light emission side is added to the liquid paste as a dispersion medium. Apply aerosol After forming by baking and then forming a permeation layer on the porous oxide semiconductor layer, the electrolyte is passed through the permeation layer of the laminate in which the porous oxide semiconductor layer and the permeation layer are formed on the conductive substrate. Since the solution is permeated, the permeation layer functions to permeate the electrolyte solution from the end side of the porous oxide semiconductor layer itself to the permeation layer itself, and quickly spread it throughout the porous oxide semiconductor layer. Therefore, even after the permeation layer as a spacer and other layers have already been formed on the porous oxide semiconductor layer, the electrolyte solution can be appropriately injected into the porous oxide semiconductor layer. Therefore, a porous oxide semiconductor layer, a permeation layer as a spacer, and other layers can be easily manufactured with a small amount of material as a laminate.

  Further, the average particle diameter of the sintered particles of the oxide semiconductor fine particles forming the porous oxide semiconductor layer on the light emitting side is the average particle diameter of the sintered particles of the oxide semiconductor fine particles forming the porous oxide semiconductor layer on the light incident side. Since it can be made larger than the particle size, a photoelectric conversion device having the above-described excellent effects can be manufactured. Note that in the stacked body, the other layers include a conductive layer functioning as an electrode, a sealing layer for hermetically sealing the entire stacked body, and the like.

  In addition, according to the second method for producing a photoelectric conversion device of the present invention, from a sintered body of oxide semiconductor fine particles formed by laminating a plurality of layers, which adsorbs a dye and contains an electrolyte, on a conductive substrate. A method for producing a dye-sensitized photoelectric conversion device in which a porous oxide semiconductor layer, an infiltration layer into which an electrolyte solution permeates and a permeation layer in which the infiltrated solution is retained, and a counter electrode layer are sequentially formed The average particle diameters of the primary particles before sintering of the oxide semiconductor fine particles constituting each layer of the porous oxide semiconductor layer formed by laminating are the same, and the porous oxide semiconductor layer on the light incident side is dispersed in the dispersed phase. Is a primary particle of oxide semiconductor fine particles and the dispersion medium is formed by applying and baking a colloidal liquid paste composed of a liquid, and the porous oxide semiconductor layer on the light emitting side is formed into an organic resin as a dispersed phase in the liquid paste Of fine particles A laminate formed by applying and baking a liquid paste and then forming a permeation layer on the porous oxide semiconductor layer and then forming the porous oxide semiconductor layer and the permeation layer on the conductive substrate. Since the electrolyte solution is allowed to permeate through the permeation layer, the permeation layer permeates the electrolyte solution from the end side of the porous oxide semiconductor layer to the permeation layer itself, and quickly penetrates the entire porous oxide semiconductor layer. In order to spread, the electrolyte solution is appropriately injected into the porous oxide semiconductor layer even after the penetration layer and other layers as spacers have already been formed on the porous oxide semiconductor layer. be able to. Therefore, a porous oxide semiconductor layer, a permeation layer as a spacer, and other layers can be easily manufactured with a small amount of material as a laminate.

  Further, the average particle diameter of the sintered particles of the oxide semiconductor fine particles forming the porous oxide semiconductor layer on the light emitting side is the average particle diameter of the sintered particles of the oxide semiconductor fine particles forming the porous oxide semiconductor layer on the light incident side. Since it can be made larger than the particle size, a photoelectric conversion device having the above-described excellent effects can be manufactured. Note that in the stacked body, the other layers include a conductive layer functioning as an electrode, a sealing layer for hermetically sealing the entire stacked body, and the like.

  In addition, according to the third method for producing a photoelectric conversion device of the present invention, the oxide semiconductor fine particle sintered body formed by laminating a plurality of layers, which adsorbs a dye and contains an electrolyte, on a conductive substrate. A method for producing a dye-sensitized photoelectric conversion device in which a porous oxide semiconductor layer, an infiltration layer into which an electrolyte solution permeates and a permeation layer in which the infiltrated solution is retained, and a counter electrode layer are sequentially formed The average particle diameters of the primary particles before sintering of the oxide semiconductor fine particles constituting each layer of the porous oxide semiconductor layer formed by laminating are the same, and the porous oxide semiconductor layer on the light incident side is dispersed in the dispersed phase. Is a primary particle of oxide semiconductor fine particles and the dispersion medium is formed by applying and baking a colloidal liquid paste composed of a liquid, and the porous oxide semiconductor layer on the light emitting side is formed into an organic resin as a dispersed phase in the liquid paste Of fine particles In addition, an aerosol added with a gas as a dispersion medium is applied and baked, and then a permeation layer is formed on the porous oxide semiconductor layer, and then the porous oxide semiconductor layer and the permeation layer are formed on the conductive substrate. Since the electrolyte solution is permeated through the permeation layer of the formed laminate, the permeation layer permeates the permeation layer itself from the end side of the porous oxide semiconductor layer so that the permeation layer itself becomes porous. Even after the permeation layer and other layers as spacers have already been formed on the porous oxide semiconductor layer, the electrolyte solution can be used to spread the entire oxide semiconductor layer. The layer can be properly injected. Therefore, a porous oxide semiconductor layer, a permeation layer as a spacer, and other layers can be easily manufactured with a small amount of material as a laminate.

  Further, the average particle diameter of the sintered particles of the oxide semiconductor fine particles forming the porous oxide semiconductor layer on the light emitting side is the average particle diameter of the sintered particles of the oxide semiconductor fine particles forming the porous oxide semiconductor layer on the light incident side. Since it can be made larger than the particle size, a photoelectric conversion device having the above-described excellent effects can be manufactured. Note that in the stacked body, the other layers include a conductive layer such as a counter electrode layer functioning as an electrode, a sealing layer for hermetically sealing the entire stacked body, and the like.

  The photovoltaic device of the present invention uses the photoelectric conversion device of the present invention as a power generation means, and supplies the generated power of the power generation means to a load. This is the operational effect of the photoelectric conversion device of the present invention. The porous oxide semiconductor layer that adsorbs the dye on the light incident side well scatters and absorbs short wavelength light well, and the porous oxide semiconductor layer that adsorbs the dye on the light exit side scatters long wavelength light well. It becomes a highly reliable photovoltaic device with high conversion efficiency utilizing the effect that it can be confined and absorbed well, the photocurrent is increased to increase the conversion efficiency, and it can be easily configured with few materials. .

  DESCRIPTION OF EMBODIMENTS Embodiments of a photoelectric conversion device, a manufacturing method thereof, and a photovoltaic device of the present invention will be described below in detail with reference to FIGS. In addition, in each figure, the same code | symbol is attached | subjected to the same member.

  A cross-sectional view of the photoelectric conversion device of the present invention is shown in FIG. The photoelectric conversion device 1 of FIG. 1 has a porous oxide semiconductor layer composed of two layers, and is formed on a conductive substrate 2 composed of a substrate 2a and a transparent conductive layer 2b formed on one main surface thereof. 1st porous oxide semiconductor layer 3 which adsorb | sucked pigment | dye (not shown), 2nd porous oxide semiconductor layer 4 which adsorb | sucked pigment | dye, osmosis | permeation layer 7, counter electrode layer 8, and sealing as a sealing member In this configuration, the electrolyte solution (not shown) injected into the portion 9, the porous oxide semiconductor layers 3 and 4, and the permeation layer 7 is provided.

  That is, the photoelectric conversion device 1 of the present invention has a porous oxide semiconductor layer 3 and 4 that has adsorbed (supported) a dye on the conductive substrate 2 and the permeation in which the electrolyte solution permeates and the permeated solution is retained. In the dye-sensitized photoelectric conversion device 1 in which the layer 7 and the counter electrode layer 8 are sequentially formed, the porous oxide semiconductor layers 3 and 4 are formed by laminating a plurality of layers and are porous on the light incident side. The arithmetic average roughness of the surface of the oxide semiconductor layer 3 or the surface of the fractured surface is smaller than the arithmetic average roughness of the surface of the porous oxide semiconductor layer 4 on the light emitting side or the surface of the fractured surface, and is porous on the light incident side. The oxide semiconductor layer 3 is thicker than the porous oxide semiconductor layer 4 on the light emission side.

  The permeation layer 7 of the present invention may cover not only the upper surface of the porous oxide semiconductor layer 3 but also the side surfaces.

  The permeation layer 7 in which the electrolyte solution permeates and the permeated solution is retained is porous, and preferably has an arithmetic average roughness of the surface or the surface of the fractured surface of about 0.01 to 1 μm. belongs to. The value of the arithmetic average roughness is substantially equivalent to the size of the pores in the permeation layer 7, and is not less than a value (0.01 μm) at which the electrolyte solution easily permeates. This corresponds to a value (1 μm) or less held by the surface tension. More preferably, the arithmetic average roughness is 0.1 to 0.3 μm.

  In the above configuration, the osmotic layer 7 is interposed between the counter electrode layer 8 and the porous oxide semiconductor layers 3 and 4 formed thereon so that they do not come into direct contact with each other and ensure a certain distance. It functions mainly as a spacer and preferably scatters light moderately as a porous material including a large number of pores. A sintered body is suitable as such a porous material. Further, in the manufacturing process of the photoelectric conversion device 1, the osmotic layer 7 adsorbs the dye to the entire porous oxide semiconductor layers 3, 4 by allowing a solution containing a dye or an electrolyte solution to penetrate into the osmotic layer 7 itself. Or having the electrolyte solution spread all over the porous oxide semiconductor layers 3 and 4 to which the dye is adsorbed.

  The porous oxide semiconductor layers 3 and 4 are layers made of a semiconductor containing a large number of vacancies inside, and receive electrons photoexcited by the dye in the power generation mechanism and scatter light to effect light on the dye. It works to make it incident. The characteristic that light is scattered in the porous oxide semiconductor layers 3 and 4 has wavelength dependency, and the characteristic is the surface of the porous oxide semiconductor layers 3 and 4 (the upper surface and the lower surface of the layer), or its It can be controlled by the arithmetic average roughness of the fracture surface. The arithmetic average roughness of the surface of the porous oxide semiconductor layer 3 on the light incident side or the surface of the fracture surface is smaller than the arithmetic average roughness of the surface of the porous oxide semiconductor layer 4 on the light emission side or the surface of the fracture surface. The porous oxide semiconductor layer 3 on the light incident side scatters and confines short wavelength light (400 to 600 nm) well, but transmits long wavelength light (600 to 900 nm) well. In addition, since the porous oxide semiconductor layer 3 can be formed thick because it easily transmits long-wavelength light, it absorbs short-wavelength light well by the dye adsorbed by the porous oxide semiconductor layer 3 on the light incident side, and arithmetically. Since the average roughness is small, the surface area is increased and the amount of the dye adsorbed is increased, so that the photocurrent from the dye due to the short wavelength light can be increased in the porous oxide semiconductor layer 3.

  On the other hand, the porous oxide semiconductor layer 4 on the light emitting side can scatter and confine long wavelength light inside thereof. In addition, the porous oxide semiconductor layer 4 absorbs long wavelength light, and since it is not necessary to increase the thickness, the resistance of the conductive path can be reduced. Long-wavelength light is well absorbed by the dye adsorbed on the semiconductor layer 4 to increase the photocurrent from the dye by the long-wavelength light in the porous oxide semiconductor layer 4 and to efficiently take out the current from the dye with low resistance. be able to.

  Note that the arithmetic average roughness of the porous oxide semiconductor layers 3 and 4 has a magnitude relationship between the surface (the upper surface and the lower surface of the layer) or the arithmetic average roughness of the fractured surface between the light incident side and the light emitting side. However, the arithmetic average roughness of at least the surfaces of the porous oxide semiconductor layers 3 and 4 may be in the above magnitude relationship. That is, if the arithmetic average roughness of the surface of the porous oxide semiconductor layer 3 on the light incident side is smaller than the arithmetic average roughness of the surface of the porous oxide semiconductor layer 4 on the light emitting side, naturally, The arithmetic mean roughness of the surface of the fracture surface corresponding to the sintered surface of the porous oxide semiconductor layer 3 on the light incident side is that of the fracture surface corresponding to the sintered surface of the porous oxide semiconductor layer 4 on the light emission side. This is because it is considered to be smaller than the arithmetic average roughness of the surface.

  The arithmetic average roughness of the surface of the permeation layer 7 or the surface of the fracture surface is preferably larger than that of the porous oxide semiconductor layers 3 and 4. In this case, the permeation layer 7 has an average particle size of the fine particles constituting it larger than the average particle size of the porous oxide semiconductor layer 3, and the pores inside the permeation layer 7 become larger. More electrolyte can exist in the inside of the adjacent osmosis | permeation layer 7, the electrical resistance by the electrolyte contained in the osmosis | permeation layer 7 becomes small, and conversion efficiency can be improved.

  The arithmetic average roughness of the surface of the porous oxide semiconductor layers 3 and 4 or the surface of the fractured surface is determined by measuring the surface of the porous oxide semiconductor layer 4 which is an exposed surface, etc. It can be measured with a needle type surface roughness measuring device), an atomic force microscope (AFM) or the like. Moreover, when measuring the surface of the torn surface of the porous oxide semiconductor layers 3 and 4, it is preferable to measure with an atomic force microscope and a laser microscope. The porous oxide semiconductor layer 3 has a film thickness of 3 to 25 μm, more preferably 6 to 18 μm. The width (thickness) of the fracture surface is narrow, and a means that can be measured within a range of several μm is an atom. This is because an atomic force microscope (AFM) and a laser microscope are excellent.

  In the method of manufacturing the photoelectric conversion device 1 in FIG. 1, the first porous oxide semiconductor layer 3 is applied and formed on the conductive substrate 2 and baked, and then the second porous oxide semiconductor layer 4 is formed. Coating and baking, and then applying and baking the permeation layer 7, then forming the counter electrode layer 8, and then immersing the conductive substrate 2 in the dye solution to saturate the porous oxide semiconductor layer 3 4, the dye is adsorbed, and then an electrolyte solution is injected between the counter electrode layer 8 and the conductive substrate 2, and then the outer periphery of the counter electrode layer 8 and the conductive substrate 2 is sealed with the sealing portion 9. And completed.

  That is, the first manufacturing method of the photoelectric conversion device of the present invention is based on a sintered body of oxide semiconductor fine particles that are formed by laminating a plurality of layers, adsorbing and holding a dye on a conductive substrate 2. Porous dye semiconductor layers 3 and 4, a method for producing a dye-sensitized photoelectric conversion device 1 in which an electrolyte solution permeates and a permeation layer 7 and a counter electrode layer 8 in which the permeated solution is retained are sequentially formed And the average particle diameter of the primary particles before sintering of the oxide semiconductor fine particles constituting each of the porous oxide semiconductor layers 3 and 4 formed by laminating a plurality of layers is the same, The porous oxide semiconductor layer 3 is formed by applying and baking a colloidal liquid paste in which the dispersed phase is primary particles of oxide semiconductor fine particles and the dispersion medium is liquid. 4 gas as a dispersion medium in liquid paste The applied aerosol is applied and baked, and then a permeation layer 7 is formed on the porous oxide semiconductor layer 4. Then, the porous oxide semiconductor layers 3 and 4 and the permeation layer 7 are formed on the conductive substrate 2. The electrolyte solution is allowed to permeate through the permeation layer 7 of the laminate formed by forming. It is also possible to permeate the electrolyte solution through the side surface of the laminate and the permeation layer 7.

  The second method for producing a photoelectric conversion device of the present invention comprises a sintered body of oxide semiconductor fine particles that are formed by adsorbing a dye and containing an electrolyte and laminating a plurality of layers on a conductive substrate 2. In the manufacturing method of the dye-sensitized photoelectric conversion device 1 in which the porous oxide semiconductor layers 3 and 4, the permeation layer 7 in which the electrolyte solution permeates and the permeated solution is held, and the counter electrode layer 8 are sequentially formed. The average particle diameter of the primary particles before sintering of the oxide semiconductor fine particles constituting each of the porous oxide semiconductor layers 3 and 4 formed by laminating a plurality of layers is the same, and the porous material on the light incident side The oxide semiconductor layer 3 is formed by applying and baking a colloidal liquid paste in which the dispersed phase is primary particles of oxide semiconductor fine particles and the dispersion medium is a liquid, and the porous oxide semiconductor layer 4 on the light emitting side is formed. Organic tree as a dispersed phase in a liquid paste A liquid paste to which fine particles are added is applied and fired, and then a permeation layer 7 is formed on the porous oxide semiconductor layer 4, and then the porous oxide semiconductor layers 3, 4 are formed on the conductive substrate 2. The electrolyte solution is permeated through the permeation layer 7 of the laminate formed with the permeation layer 7. It is also possible to permeate the electrolyte solution through the side surface of the laminate and the permeation layer 7.

  The third method for producing a photoelectric conversion device of the present invention comprises a sintered body of oxide semiconductor fine particles comprising a plurality of layers laminated to adsorb a pigment and contain an electrolyte on a conductive substrate 2. In the method of manufacturing the dye-sensitized photoelectric conversion device 1 in which the porous oxide semiconductor layers 3 and 4, the permeation layer 7 in which the electrolyte solution permeates and the permeated solution is held, and the counter electrode layer 8 are sequentially formed. The average particle diameter of primary particles before sintering of the oxide semiconductor fine particles constituting each of the porous oxide semiconductor layers 3 and 4 formed by laminating a plurality of layers is the same, and the porous oxide on the light incident side The semiconductor layer 3 is formed by applying and baking a colloidal liquid paste in which the dispersed phase is primary particles of oxide semiconductor fine particles and the dispersion medium is a liquid, and the porous oxide semiconductor layer 4 on the light emitting side is formed. Organic tree as dispersed phase in liquid paste In addition, an aerosol added with a fine particle and a gas added as a dispersion medium is applied and baked, and then a permeation layer 7 is formed on the porous oxide semiconductor layer 4, and then a porous material is formed on the conductive substrate 2. In this structure, the electrolyte solution is permeated through the permeation layer 7 of the laminated body in which the oxide semiconductor layers 3 and 4 and the permeation layer 7 are formed. It is also possible to permeate the electrolyte solution through the side surface of the laminate and the permeation layer 7.

  Here, the firing of the first porous oxide semiconductor layer 3 is preliminarily fired (dried) at a low temperature, and then the second porous oxide semiconductor layer 4 is applied and formed, and then fired together. Also good.

  FIG. 2 shows a cross-sectional view of another example of the embodiment of the photoelectric conversion device of the present invention. The photoelectric conversion device 1 ′ shown in FIG. 2 has a porous oxide semiconductor layer composed of three layers, and is formed on a conductive substrate 2 and is a first porous oxide that adsorbs a dye (not shown). Semiconductor layer 3, second porous oxide semiconductor layer 4 adsorbing dye, third porous oxide semiconductor layer 5 adsorbing dye, permeation layer 7, counter electrode layer 8, sealing part 9, porous oxidation In this configuration, the electrolyte solution (not shown) injected into the physical semiconductor layers 3, 4, 5 and the permeation layer 7 is provided.

  In the method of manufacturing the photoelectric conversion device 1 ′ of FIG. 2, the first porous oxide semiconductor layer 3 is applied and formed on the conductive substrate 2, fired, and then the third porous oxidation as an intermediate layer. The organic semiconductor layer 5 is applied and fired, then the second porous oxide semiconductor layer 4 is applied and fired, then the permeation layer 7 is applied and fired, and then the counter electrode layer 8 Next, the conductive substrate 2 is immersed in the dye solution so that the dye is adsorbed to the porous oxide semiconductor layers 3, 4, and 5, and then the electrolyte is interposed between the counter electrode layer 8 and the conductive substrate 2. The solution is injected, and thereafter the outer peripheral portion of the counter electrode layer 8 and the conductive substrate 2 is sealed by the sealing portion 9 to complete.

  According to the photoelectric conversion devices 1 and 1 ′ of the present invention, in order to inject the electrolyte solution after forming a thin laminate between the conductive substrate 2 and the counter electrode layer 8 in this way, the conductive substrate 2 The counter electrode layer 8 is advantageous in that the distance between the counter electrode layer 8 and the counter electrode layer 8 can be made as thin as possible. Moreover, even though the pores contained in the porous oxide semiconductor layers 3 and 4 (5) are small, the permeation layer 7 is an electrolyte solution throughout the porous oxide semiconductor layers 3 and 4 (5). Can be reliably distributed, and light of a desired wavelength can be effectively scattered by appropriately setting the size of the pores included in the porous oxide semiconductor layers 3, 4 (, 5). Therefore, it is advantageous in that the photoelectric conversion efficiency is improved.

  Next, each element constituting the above-described photoelectric conversion devices 1 and 1 ′ will be described in detail.

<Conductive substrate>
As the conductive substrate 2, a substrate having a transparent conductive layer 2b on a light-transmitting substrate 2a is preferable. As the material of the substrate 2a, glass such as white plate glass, soda glass, borosilicate glass, or an inorganic material such as ceramics may be able to withstand the firing temperature of the porous oxide semiconductor layer 3 and the like. The thickness of the substrate 2a is 0.05 to 8 mm, preferably 0.2 to 4 mm in terms of mechanical strength.

As the transparent conductive layer 2b, a transparent conductive layer of metal oxide doped with fluorine or metal is used. For example, impurities (F, Sb, etc.) doped tin oxide film (SnO ₂ film), impurities (Ga, Al, etc.) doped zinc oxide film (ZnO film), tin doped indium oxide film (ITO film) and impurity doped oxidation An indium film (In ₂ O ₃ film), a niobium-doped titanium oxide film, or the like may be used.

Among these, a fluorine-doped tin dioxide film (SnO ₂ : F film) formed by thermal CVD or spray pyrolysis is best because it has heat resistance and low material cost. Examples of the method for forming the transparent conductive layer 2b include a thermal CVD method, a spray pyrolysis method, a sputtering method, a vacuum deposition method, an ion plating method, a dip coating method, a solution growth method, and a sol-gel method.

  The thickness of the transparent conductive layer 2b is 0.001 to 10 μm, preferably 0.05 to 2.0 μm.

  Further, the transparent conductive layer 2b may be an extremely thin metal film such as Au, Pd, or Al formed by a vacuum deposition method or a sputtering method. Further, these metal films may be laminated and used in various combinations. For example, as the transparent conductive layer 2b, a Ti layer, an ITO layer, and a Ti layer may be sequentially laminated, and a laminated film with improved adhesion and corrosion resistance is obtained.

  Further, the substrate 2a of the conductive substrate 2 may be non-translucent when light is incident from the opposite direction (upper side in FIG. 1), a thin metal sheet made of titanium, stainless steel, nickel or the like, or carbon A titanium sheet, a stainless steel layer, a conductive metal oxide layer for preventing corrosion due to electrolyte contained in the porous oxide semiconductor layers 3 and 4 and the permeation layer 7 on the surface of a thin sheet made of, or an insulating substrate Etc. may be coated.

  In the present invention, the porous oxide semiconductor layers 3, 4 and 5 are fired (firing temperature 400 ° C. to 550 ° C.), so that the porous oxide semiconductor layers 3, 4, 5 are directly applied to a resin substrate having low heat resistance. Cannot be formed. In such a case, the porous oxide semiconductor layers 3, 4, 5 are first formed and fired on a heat-resistant support substrate (a metal sheet such as aluminum), and then the transparent conductive layer 2 b is formed or the transparent conductive layer 2 b is formed. The porous oxide semiconductor films 3, 4 and 5 may be transferred and bonded onto the substrate 2a made of the coated resin, and then the supporting substrate may be peeled off.

  The material of the substrate 2a made of resin is preferably a material such as polycarbonate (PC), acrylic resin, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, or the like. With the transfer type manufacturing method as described above, the low-cost substrate 2a can be used, and flexibility (flexibility) can be imparted to the substrate 2a. Considering the substrate 2a made of resin, the thickness of the conductive substrate 2 is 0.005 to 5 mm, preferably 0.01 to 2 mm in terms of mechanical strength.

<Porous oxide semiconductor layer>
As the porous oxide semiconductor layers 3, 4 and 5, a porous n-type oxide semiconductor layer made of titanium dioxide or the like is preferable. As shown in FIGS. 1 and 2, porous oxide semiconductor layers 3 and 4 or porous oxide semiconductor layers 3 to 5 are sequentially formed on a conductive substrate 2.

As the material and composition of the porous oxide semiconductor layers 3 to 5, titanium oxide (TiO ₂ ) is optimal, and as other materials, titanium (Ti), zinc (Zn), tin (Sn), niobium ( Nb), indium (In), yttrium (Y), lanthanum (La), zirconium (Zr), tantalum (Ta), hafnium (Hf), strontium (Sr), barium (Ba), calcium (Ca), vanadium ( V), at least one metal oxide semiconductor of a metal element such as tungsten (W) is preferable, and nitrogen (N), carbon (C), fluorine (F), sulfur (S), chlorine (Cl), You may contain 1 or more types of nonmetallic elements, such as phosphorus (P). Titanium oxide or the like is preferable because it has an electron energy band gap in the range of 2 to 5 eV, which is larger than the energy of visible light. The porous oxide semiconductor layers 3 to 5 are preferably n-type semiconductors whose conduction band is lower than the conduction band of the dye in the electron energy level.

  The porous oxide semiconductor layers 3 to 5 are all composed of oxide semiconductor fine particles having the same primary particles, and the average particle size of the primary particles is preferably 1 to 40 nm, and more preferably 5 to 30 nm. Here, if the lower limit value 1 nm of the average particle diameter is less than this, the material cannot be refined, and if the upper limit value 40 nm is exceeded, the junction area is reduced and the photocurrent is significantly reduced.

  The porous oxide semiconductor layers 3 to 5 of the present invention are prepared by using a fine primary oxide semiconductor fine particle as a dispersion phase, and preparing a paste using an aqueous or non-aqueous solution as a dispersion medium. Are sequentially applied and fired on the conductive substrate 2. In this way, by forming the porous oxide semiconductor layers 3 to 5 with a fine oxide semiconductor and making them porous, the surface area of all the porous oxide semiconductor layers 3 to 5 as the photoactive electrode layer is increased. Therefore, light absorption, photoelectric conversion, and electron conduction can be performed efficiently.

  The porous oxide semiconductor layer 3 on the light incident side preferably has an arithmetic average roughness Ra of 0.01 to 0.06 μm, more preferably 0.015 to 0.05 μm, on the surface after firing or the surface of the fracture surface. It may be 0.055 μm. The porous oxide semiconductor layer 3 should be transparent when viewed under visible light. Since the porous oxide semiconductor layer 3 on the light incident side has a small arithmetic average roughness Ra after sintering, it scatters and confines short wavelength light (400 to 600 nm) well, but long wavelength light (600 to 900 nm). Can be formed thick because long wavelength light is easily transmitted. Therefore, short-wavelength light is well absorbed by the dye adsorbed on the porous oxide semiconductor layer 3, and the amount of dye adsorbed is large, so that the photocurrent from the dye can be increased.

In order to form the porous oxide semiconductor layer 3 on the light incident side, first, a liquid paste is prepared. The liquid paste is prepared, for example, by adding acetylacetone to TiO ₂ anatase powder, kneading with deionized water, and preparing a titanium oxide paste stabilized with a surfactant. Before applying the prepared paste, centrifugal defoaming and vacuum degassing are performed to obtain a liquid paste that does not contain bubbles, and then this liquid paste is gently dropped on the conductive substrate 2, and the doctor blade method and bar coating method. Alternatively, it may be applied uniformly and gently at a constant speed by a spinner coater method or the like.

  Next, the porous oxide semiconductor layer 3 is formed by heat treatment in the atmosphere at 300 to 600 ° C., preferably 400 to 500 ° C., for 10 to 60 minutes, preferably 20 to 40 minutes. The thickness of the porous oxide semiconductor layer 3 on the light incident side is preferably 3 to 25 μm, and more preferably 6 to 18 μm.

  The porous oxide semiconductor layer 4 on the light emitting side may have an arithmetic average roughness Ra of 0.03 to 0.2 μm, more preferably 0.04 to 0.2 μm, on the surface after firing or the surface of the fracture surface. It is good that it is 0.15 μm. The porous oxide semiconductor layer 4 should appear opaque when viewed under visible light. Due to such surface roughness after sintering, the porous oxide semiconductor layer 4 on the light emitting side scatters and confines long-wavelength light inside thereof and can be formed thin, so that the conductive path Resistance can be reduced. Therefore, the long-wavelength light is well absorbed by the dye adsorbed by the porous oxide semiconductor layer 4 on the light emitting side, and the photocurrent from the dye is increased, and the current from the dye can be efficiently extracted with low resistance. .

  In order to form the porous oxide semiconductor layer 4, a liquid paste preparation method and a coating film formation method are used, and the following three methods are particularly preferable.

  In the first method, a liquid paste is first prepared in the same manner as in the case of the porous oxide semiconductor layer 3. This liquid paste is centrifugally defoamed to obtain a liquid paste containing no bubbles. Next, using a spray coating method or the like on the conductive substrate 2, it is dropped onto the conductive substrate 2 as a liquid paste containing bubbles and applied uniformly. Alternatively, the liquid paste is stirred to include bubbles, and the liquid paste is dropped on the conductive substrate 2 and uniformly applied by a doctor blade method, a bar coat method, a spinner coater method, or the like.

  In the second method, when a liquid paste is first prepared in the same manner as described above, organic resin fine particles are mixed and kneaded, and the prepared paste is centrifugally defoamed to obtain a liquid paste containing no bubbles. Next, this liquid paste is dropped onto the conductive substrate 2 and uniformly and uniformly applied by a doctor blade method, a bar coat method, a spinner coater method or the like.

  In the third method, a liquid paste is produced in the same manner as the second method. Next, this liquid paste is dropped onto the conductive substrate 2 as a liquid paste containing bubbles using a spray coating method or the like, and uniformly applied.

  As the organic resin fine particles used in the second and third methods, spherical fine particles of acrylic resin (methacrylic ester copolymer) are particularly good, and PEG (polyethylene glycol) flakes may be used.

  Thus, the coating film obtained by any one of the first to third methods is 300 to 600 ° C., preferably 400 to 500 ° C. in the atmosphere, and 10 to 60 minutes, preferably 20 to 40 in the atmosphere. By performing the partial heat treatment, the porous oxide semiconductor layer 4 is obtained. The porous oxide semiconductor layer 4 should be opaque by visual observation under visible light.

  Here, in the first method, the dispersed bubbles give the porous oxide semiconductor layer 4 a desired surface roughness, and in the second method, the dispersed organic resin fine particles are vaporized by firing to form a porous oxide semiconductor. In the third method, a desired surface roughness is given to the layer 4, and dispersed bubbles give part of the desired surface roughness to the porous oxide semiconductor layer 4, and fine particles of the dispersed organic resin are removed by firing. To give part of the desired surface roughness.

  The thickness of the porous oxide semiconductor layer 4 is preferably 1 to 12 μm, more preferably 2 to 10 μm, and can be formed thinner than the porous oxide semiconductor film 3.

  The porous oxide semiconductor layer 5 is provided between the light incident side and light emitting side porous oxide semiconductor layers 3 and 4, and the arithmetic average roughness of the surface after firing or the surface of the fracture surface Ra should be 0.02-0.12 μm, more preferably 0.03-0.1 μm. The intermediate porous oxide semiconductor layer 5 should look translucent when viewed under visible light. The method for producing the porous oxide semiconductor layer 5 may be performed in the same manner as in the first to third methods, and the paste viscosity is adjusted to a lower value or the amount of organic resin fine particles mixed is reduced. Thus, the surface roughness Ra after firing can be set to an intermediate size.

  The intermediate wavelength light (550 to 650 nm) of short wavelength light and long wavelength light is scattered by setting the arithmetic average roughness of the surface of the porous oxide semiconductor layer 5 or the surface of the fractured surface to an intermediate size after sintering. Thus, the intermediate wavelength light is well absorbed by the dye adsorbed on the porous oxide semiconductor layer 5, and the photocurrent from the dye can be increased.

  The film thickness of the porous oxide semiconductor layer 5 is preferably 1 to 10 μm, more preferably 3 to 8 μm, which is thinner than the porous oxide semiconductor film 3 and thicker than the porous oxide semiconductor film 4.

The graph of FIG. 3 shows the relationship between the surface roughness Ra of the porous oxide semiconductor layer made of TiO ₂ thus obtained and the absorption wavelength. Here, arithmetic average roughness Ra was evaluated based on JIS standard B0601-1994 with a surf test apparatus (product name “SJ-400” manufactured by Mitutoyo Corporation). The absorption wavelength was evaluated by determining the absorption peak wavelength of the light spectrum absorbed by the porous oxide semiconductor layer from the difference in light transmittance before and after forming the porous oxide semiconductor layer on the conductive substrate 2.

  FIG. 3 shows that the absorption wavelength is substantially proportional to Ra of the porous oxide semiconductor layer. Therefore, the absorption wavelength can be controlled by adjusting Ra of the porous oxide semiconductor layer as in the present invention.

Further, when the surface of the porous oxide semiconductor layers 3 to 5 is treated with TiCl ₄ , that is, immersed in a TiCl ₄ solution for about 10 hours, washed with water, and baked at 450 ° C. for 30 minutes, the electronic conductivity is increased. Improves the conversion efficiency.

  In addition, an extremely thin dense layer of an n-type oxide semiconductor may be inserted between the porous oxide semiconductor layer 3 and the conductive substrate 2, and the reverse current can be suppressed, so that the conversion efficiency is increased.

<Dye>
Examples of the sensitizing dye include a ruthenium-tris, ruthenium-bis, osmium-tris, osmium-bis transition metal complex, a polynuclear complex, or a ruthenium-cis-diaqua-bipyridyl complex, or a phthalocyanine or porphyrin. Xanthene dyes such as polycyclic aromatic compounds and rhodamine B are preferred.

  In order to adsorb the dye to the porous oxide semiconductor layers 3 to 5, the dye has at least one carboxyl group, sulfonyl group, hydroxamic acid group, alkoxy group, aryl group, phosphoryl group as a substituent. It is valid. Here, the substituent can strongly chemisorb the dye itself to the porous oxide semiconductor layers 3 to 5 and can easily transfer charges from the excited state dye to the porous oxide semiconductor layers 3 to 5. I just need it.

Examples of the method of adsorbing the dye on the porous oxide semiconductor layers 3 to 5 include a method of immersing the porous oxide semiconductor layers 3 to 5 formed on the conductive substrate 2 in a solution in which the dye is dissolved. It is done. Examples of the solvent of the solution for dissolving the dye include a mixture of one or more alcohols such as ethanol, ketones such as acetone, ethers such as diethyl ether, nitrogen compounds such as acetonitrile, and the like. The dye concentration in the solution is preferably about 5 × 10 ⁻⁵ to 2 × 10 ⁻³ mol / l (l (liter): 1000 cm ³ ).

  When the conductive substrate 2 on which the porous oxide semiconductor layers 3 to 5 are formed is immersed in the solution in which the dye is dissolved, the temperature conditions of the solution and the atmosphere are not particularly limited, and for example, under atmospheric pressure or vacuum Among these, room temperature or conditions for heating the conductive substrate 2 may be mentioned. The immersion time can be appropriately adjusted depending on the type of the dye and the solution, the concentration of the solution, and the like. Thereby, a pigment | dye can be made to adsorb | suck to the porous oxide semiconductor layers 3-5.

<Penetration layer>
The permeation layer 7 is, for example, a thin film made of a porous body in which fine particles such as aluminum oxide are sintered and the electrolyte solution can permeate by capillary action and the solution is held, for example, by surface tension. There should be. As shown in FIGS. 1 and 2, a permeation layer 7 is formed on the porous oxide semiconductor layer 4. The state in which the electrolyte solution is held in the osmotic layer 7 by, for example, surface tension is a state in which the electrolyte solution that has once penetrated and absorbed the osmotic layer 7 does not leak to the outside. It can be easily distinguished by observation.

  The arithmetic average roughness of the surface or fractured surface of the permeation layer 7 is preferably larger than the arithmetic average roughness of the surface of the porous oxide semiconductor layers 3, 4, 5 or the surface of the fractured surface. The average particle size of the fine particles constituting the same is larger than the average particle size of the porous oxide semiconductor layers 3, 4, 5. As a result, since the pores in the permeation layer 7 are increased, more electrolyte can be present in the permeation layer 7 adjacent to the counter electrode layer 8, and the electric resistance due to the electrolyte contained in the permeation layer 7 is reduced. , Conversion efficiency can be increased.

  Further, the osmotic layer 7 can keep the gap between the porous oxide semiconductor layer 4 and the counter electrode layer 8 narrow and constant. Therefore, the thickness of the osmotic layer 7 is uniform and as thin as possible. It should be porous so that the solution can penetrate. The thinner the permeation layer 7 is, that is, the shorter the redox reaction distance or the hole transport distance, the higher the conversion efficiency. The more uniform the permeation layer 7 is, the higher the reliability and A conversion device can be realized.

  The thickness of the osmotic layer 7 is preferably 0.01 to 300 μm, and more preferably 0.05 to 50 μm. If the thickness is less than 0.01 μm, the electrolyte solution retained in the permeation layer 7 is reduced, so that the electrical resistance of the electrolyte increases and the conversion efficiency tends to decrease. If it exceeds 300 μm, the gap between the porous oxide semiconductor layer 4 and the counter electrode layer 8 becomes large, so that the electrical resistance due to the electrolyte becomes large and the conversion efficiency tends to decrease.

When the permeation layer 7 is made of insulator particles, the material is preferably Al ₂ O ₃ , SiO ₂ , ZrO ₂ , CaO, SrTiO ₃ , BaTiO ₃ or the like. Among these, Al ₂ O ₃ is particularly excellent in terms of insulation, mechanical strength (hardness) and the like that prevent short circuit between the counter electrode layer 8 and the porous oxide semiconductor layer 4 and is white. It is preferable because it does not absorb light of a specific color and can prevent a decrease in conversion efficiency.

Also, if the permeation layer 7 is formed of an oxide semiconductor particles, as the material _{thereof, TiO 2, SnO 2, ZnO} , CoO, NiO, FeO, Nb 2 O 5, Bi 2 O 3, MoO 2, MoS 2, Cr ₂ O ₃ , SrCu ₂ O ₂ , WO ₃ , La ₂ O ₃ , Ta ₂ O ₅ , CaO—Al ₂ O ₃ , In ₂ O ₃ , Cu ₂ O, CuAlO, CuAlO ₂ , CuGaO _{2 and the} like are preferable. Among these, in particular, TiO ₂ adsorbs the dye, so that it can contribute to the improvement of conversion efficiency, and since it is a semiconductor, a short circuit between the counter electrode layer 8 and the porous oxide semiconductor layer 4 can be suppressed.

  When the osmotic layer 7 is a porous body made up of granular materials, needle-like bodies, columnar bodies, etc. of these materials, it can contain an electrolyte solution (not shown), Conversion efficiency can be increased. Moreover, the average particle diameter or average line diameter of the granular material, needle-like body, columnar body, and the like constituting the permeation layer 7 may be 5 to 800 nm, and more preferably 10 to 400 nm. Here, if the lower limit of the average particle diameter or the average wire diameter of 5 to 800 nm is less than this, the material cannot be refined, and if the upper limit is exceeded, the sintering temperature is increased.

  Moreover, by making the osmotic layer 7 a porous body, the surface of the osmotic layer 7 and the porous oxide semiconductor layer 4 and their interfaces become uneven, thereby providing a light confinement effect and further improving the conversion efficiency. Can do.

  As the low temperature growth method of the osmotic layer 7, an electrodeposition method, an electrophoretic electrodeposition method, a hydrothermal synthesis method, or the like is preferable.

  The penetrating layer 7 may have an arithmetic average roughness (Ra) of 0.1 μm or more, more preferably 0.1 to 1 μm, and even more preferably 0. It is good that it is 1-0.3 micrometer. When Ra on the surface of the permeation layer 7 or the surface of the fracture surface is less than 0.1 μm, the dye solution or the electrolyte solution is difficult to permeate. Moreover, when Ra of the surface of the osmosis | permeation layer 7 or the surface of a torn surface exceeds 1 micrometer, the adhesiveness of the osmosis | permeation layer 7 and the porous oxide semiconductor layer 4 will deteriorate easily. Further, when Ra exceeds 1 μm, it is difficult to form the penetration layer 7 in the first place. Here, the definition of Ra follows the provisions of JIS-B-0601 and ISO-4287.

  The Ra of the surface of the permeation layer 7 or the surface of the fractured surface is substantially equivalent to the size of the pores inside the permeation layer 7, and if Ra is 0.1 μm, the size of the pores is also substantially 0. .1 μm.

  The Ra on the surface of the permeation layer 7 may be measured, for example, as follows. The surface of the permeation layer 7 is measured using a stylus type surface roughness measuring machine, for example, a surf test (SJ-400) manufactured by Mitutoyo Corporation. The measurement method and procedure may follow the surface shape evaluation method and procedure defined in JIS-B-0633 and ISO-4288. Measurement points should avoid surface defects such as scratches. When the surface of the osmotic layer 7 is isotropic, the measurement direction may be set arbitrarily. What is necessary is just to set a measurement distance, ie, evaluation length, appropriately according to the value of Ra. As a specific example, for example, when Ra is larger than 0.02 μm and smaller than or equal to 0.1 μm, the evaluation length may be 1.25 mm. In this case, the cut-off value for the roughness curve may be 0.25 mm. Further, the arithmetic mean roughness Ra of the surface of the fracture surface of the permeation layer 7 may be measured in the same manner as the surface of the permeation layer 7.

  Moreover, what is necessary is just to fracture | rupture the osmosis | permeation layer 7, for example as follows. First, the surface of the translucent substrate 2 opposite to the transparent conductive layer is scratched using a diamond cutter. The force applied at this time may be so strong that scratches can be visually confirmed and weak enough that no glass powder is produced. Next, the laminated body is sandwiched using pliers, and the laminated body including the osmotic layer 7 is broken along the scratches attached to the light-transmitting substrate 2.

  Further, the breakage after scratching the translucent substrate 2 may be as follows. First, a laminated body is placed on a block-like table with the translucent substrate 2 facing upward. At this time, the edge of the block-shaped base and the scratch attached to the translucent substrate 2 are made parallel, and the scratch attached to the translucent board 2 is held in the air at a distance of about 1 mm from the edge of the block-shaped base. Then, the laminate is fixed. Next, a plate-shaped jig having a width longer than that of the laminated body, for example, a stainless plate or the like is placed on both sides of the scratch attached to the translucent substrate 2. Next, while fixing the jig placed on the part of the laminated body on the block-like base, pressing the jig placed on the part held in the air of the laminated body downward, the permeation layer The laminate including 7 is broken. When the permeation layer 7 is broken, the fracture surface may be easily observed by making the fracture surface linear.

  The permeation layer 7 is preferably a porous body having a porosity of preferably 20 to 80%, and more preferably 40 to 60%. If it is less than 20%, it is difficult for the dye solution or the electrolyte solution to permeate, and if it exceeds 80%, the adhesion between the permeation layer 7 and the porous oxide semiconductor layer 4 tends to deteriorate.

  For the porosity of the permeation layer 7, the isothermal adsorption curve of the sample is obtained by a nitrogen gas adsorption method using a gas adsorption measuring device, the void volume is obtained by the BJH method, CI method, DH method, etc. Can be obtained from the particle density.

Further, when the porosity of the permeation layer 7 is increased within the above range, the penetration of the dye solution can be accelerated, and the dye can be reliably adsorbed to the porous oxide semiconductor layers 3, 4, 5. The resistance of the electrolyte is reduced, and the conversion efficiency can be further increased. As a specific example of forming the permeation layer 7 having a large porosity, for example, a paste in which aluminum oxide (Al ₂ O ₃ ) fine particles (average particle size 31 nm) and polyethylene glycol (molecular weight of about 20,000) are mixed is fired. That's fine. In this case, 70 wt.% Of aluminum oxide fine particles (average particle size 31 nm) are mixed with 30 wt% of titanium oxide (TiO ₂ ) fine particles (average particle size 180 nm) having a larger average particle size. May be. By adjusting these weight ratios, average particle diameters, and materials, a larger porosity can be obtained.

  The electrolyte solution that has permeated into the permeation layer 7 is held in the permeation layer 7 by, for example, surface tension. In order to hold the electrolyte solution in the permeation layer 7, the pore size of the permeation layer 7 is set to an appropriate value according to the surface tension and density of the electrolyte solution and the contact angle between the electrolyte solution and the permeation layer 7. That's fine. As a specific example, for example, an electrolyte solution prepared by mixing tetrapropylammonium iodide, lithium iodide, iodine, or the like with ethylene carbonate, acetonitrile, methoxypropionitrile, or the like is used, and aluminum oxide or titanium oxide is used. When the permeation layer 7 is formed, the electrolyte solution can be held in the permeation layer 7 if the pore diameter of the permeation layer 7 is 1 μm or less.

The permeation layer 7 made of aluminum oxide is formed as follows. First, acetylacetone is added to Al ₂ O ₃ fine powder, then kneaded with deionized water, stabilized with a surfactant, and then polyethylene glycol is added to prepare an aluminum oxide paste. This paste is applied onto the porous oxide semiconductor layer 4 at a constant speed by a doctor blade method, a bar coating method, or the like, and is 300 to 600 ° C., preferably 400 to 500 ° C., preferably 10 to 60 minutes in the atmosphere. Then, the permeation layer 7 is formed by heat treatment for 20 to 40 minutes.

<Counter electrode layer>
As the counter electrode layer 8, a very thin film of platinum, carbon or the like having a catalytic function is preferable. In addition, an electrodeposited ultrathin film of gold (Au), palladium (Pd), aluminum (Al) or the like is preferable. Moreover, the thin film which consists of an electroconductive organic material is mentioned. Further, a porous film made of fine particles of these materials, for example, a porous film of carbon fine particles, etc. is good, the surface area of the counter electrode layer 8 is increased, and the electrolyte component of the electrolyte solution can be contained in the pores. Efficiency can be increased. It is possible to form the counter electrode layer 8 only with a thin film and integrate it on the conductive substrate 2 side, or to increase the thickness of the counter electrode layer 8 so that the counter electrode substrate as a support is not used.

  Moreover, you may use the counter electrode board | substrate which provided the counter electrode layer (catalyst layer) 8 which consists of Pt etc. in the surface at the side of the osmosis | permeation layer 7. FIG. In this case, the counter electrode layer 8 is provided on the permeation layer 7 together with the counter electrode substrate. When the counter electrode substrate is used, there is an advantage that sealing becomes easy.

When the counter electrode layer 8 is composed of a catalyst layer and a counter electrode substrate (not shown), the same substrate as the conductive substrate 2 can be used as the counter electrode substrate. For example, the counter electrode substrate is preferably made of a metal having low electrical resistance and excellent corrosion resistance, and for example, a metal sheet such as titanium or stainless steel is preferable. Alternatively, a resin substrate coated with a conductive layer may be used. Such a resin substrate is preferably a sheet of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide, polycarbonate or the like, and a metal thin film such as titanium or stainless steel is preferable as the conductive layer. Furthermore, a conductive metal oxide layer (ITO film, SnO ₂ : F film, ZnO: Al film, etc.) is provided between the metal sheet or the resin sheet with a conductive layer and the catalyst layer to prevent corrosion. If provided, reliability is increased. The thickness of these counter electrode substrates is 0.01 to 5 mm, preferably 0.1 to 3 mm in terms of mechanical strength.

<Sealing part>
1 and 2, the sealing portion 9 constituting the side walls of the photoelectric conversion devices 1 and 1 ′ provides mechanical strength capable of preventing the electrolyte component of the electrolyte solution from leaking to the outside, and externally. Provided in direct contact with the environment to protect the inside of the photoelectric conversion device 1 and prevent deterioration of the photoelectric conversion function.

  The material of the sealing portion 9 is preferably a material having a moisture absorption preventing function and sufficient adhesive strength, such as ethylene vinyl acetate copolymer resin (EVA), polyvinyl butyral (PVB), ethylene-ethyl acrylate copolymer ( EEA), fluorine resin, epoxy resin, acrylic resin, saturated polyester resin, amino resin, phenol resin, polyamideimide resin, UV curable resin, silicone resin, fluorine resin, urethane resin, coating resin used for metal roof, etc. are good .

  The thickness of the sealing part 9 is 0.01 μm to 6 mm, preferably 1 μm to 4 mm. In addition, antiglare, heat shield, heat resistance, low contamination, antibacterial, antifungal, design, high workability, rust and abrasion resistance, snow sliding, antistatic, far infrared radiation, acid resistance By providing the sealing part 9 with properties, corrosion resistance, environmental compatibility, and the like, reliability and merchantability can be further improved.

<Electrolyte>
Examples of the electrolyte include electrolyte solutions, gel electrolytes, ion conductive electrolytes such as solid electrolytes, and organic hole transport agents.

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

  Gel electrolytes are roughly classified into chemical gels and physical gels. A chemical gel is a gel formed by a chemical bond by a cross-linking reaction or the like, and a physical gel is gelled near room temperature by a physical interaction. The gel electrolyte is a gel obtained by mixing a host polymer such as polyethylene oxide, polyacrylonitrile, polyvinylidene fluoride, polyvinyl alcohol, polyacrylic acid, or polyacrylamide into acetonitrile, ethylene carbonate, propylene carbonate, or a mixture thereof. An electrolyte is preferred. When using a gel electrolyte or a solid electrolyte, a low-viscosity precursor is contained in the porous oxide semiconductor layers 3 to 5, and two-dimensional or three-dimensional crosslinking is performed by means such as heating, ultraviolet irradiation, or electron beam irradiation. It can be gelled or solidified by reacting.

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

  Examples of the molten salt of iodide include 1,1-dimethylimidazolium iodide, 1, methyl-3-ethylimidazolium iodide, 1-methyl-3-pentylimidazolium iodide, 1-methyl- 3-isopentylimidazolium iodide, 1-methyl-3-hexylimidazolium iodide, 1-methyl-3-ethylimidazolium iodide, 1,2-dimethyl-3-propylimidazole iodide, 1-ethyl- Examples thereof include 3-isopropylimidazolium iodide and pyrrolidinium iodide.

  The photoelectric conversion device 1 or 1 ′ can be used as a power generation unit, and a photovoltaic power generation device configured to supply generated power from the power generation unit to a load can be obtained. That is, when one or a plurality of the photoelectric conversion devices 1 and 1 'are used, a generator connected in series, parallel or series-parallel is used as a power generation means, and the generated power is directly supplied from this power generation means to a DC load. You may make it do. In addition, after the power generation means converts the generated power to appropriate AC power via power conversion means such as an inverter, it is possible to supply this AC power to an AC load such as a commercial power system or various electric devices. It is good also as a simple photovoltaic device. Furthermore, it is possible to use such a photovoltaic power generation device as a photovoltaic power generation device such as a photovoltaic power generation system in various aspects by installing it in a building with good sunlight, which enables high conversion efficiency and durability. A photovoltaic device can be provided.

  In addition, the photovoltaic device of the present invention uses the photoelectric conversion device 1, 1 ′ of the present invention as a power generation means and supplies the generated power of the power generation means to a load. There are effects that conversion efficiency is increased, reliability is increased, applications are expanded, manufacturing is facilitated, and cost can be reduced. In addition, the photoelectric conversion devices 1 and 1 ′ of the present invention are not limited to solar cells, but can be applied as long as they have a photoelectric conversion function, and can be applied to various light receiving elements and optical sensors. It is.

  Example 1 of the photoelectric conversion device of the present invention will be described below. A photoelectric conversion device 1 having the configuration shown in FIG. 1 was produced as follows.

First, a glass substrate (3 cm long × 2 cm wide) with a transparent conductive layer made of fluorine-doped tin oxide was used as the conductive substrate 2. On the conductive substrate 2, a light incident side porous oxide semiconductor layer 3 made of titanium dioxide was formed. This porous oxide semiconductor layer 3 was formed as follows. First, acetylacetone was added to TiO ₂ anatase powder, and then kneaded with deionized water to prepare a liquid paste of titanium oxide stabilized with a surfactant. Next, bubbles of the liquid paste were eliminated with a centrifugal defoaming device and a vacuum device. This liquid paste was gently dropped onto the conductive substrate 2, applied by a bar coating method, and baked at 450 ° C. for 30 minutes in the air to form a porous oxide semiconductor layer 3 having a thickness of about 7 μm. When the surface of the porous oxide semiconductor layer 3 was measured for the arithmetic average roughness Ra of the surface of the porous oxide semiconductor layer 3 with a surf test apparatus, Ra = 0.018 μm, which was transparent by visual observation under visible light. Met.

Next, the light emitting side porous oxide semiconductor layer 4 made of titanium dioxide was formed on the porous oxide semiconductor layer 3. This porous oxide semiconductor layer 4 was formed as follows. First, acetylacetone was added to TiO ₂ anatase powder, and then kneaded with deionized water to prepare a liquid paste of titanium oxide stabilized with a surfactant. Next, bubbles of the liquid paste were eliminated with a centrifugal defoamer. This liquid paste was uniformly coated on the porous oxide semiconductor layer 3 as a liquid paste containing bubbles by spray coating. Next, the porous oxide semiconductor layer 4 having a thickness of about 4 μm was formed by firing at 450 ° C. for 30 minutes in the air. When the surface of the surface of the porous oxide semiconductor layer 4 was measured with a surf test apparatus, the surface of the porous oxide semiconductor layer 4 was Ra = 0.084 μm, and it was opaque when viewed under visible light.

Next, a permeation layer 7 made of aluminum oxide was formed on the porous oxide semiconductor layer 4. This permeation layer 7 was formed as follows. First, acetylacetone was added to Al ₂ O ₃ powder (average particle size 31 nm), and then kneaded with deionized water to prepare an aluminum oxide paste stabilized with a surfactant. The prepared paste was applied onto the porous oxide semiconductor layer 4 at a constant speed by a doctor blade method, and baked at 450 ° C. for 30 minutes in the air to form the permeation layer 7. The arithmetic average roughness of the surface of the permeation layer 7 was 0.276 μm.

  A counter electrode layer 8 was formed on the permeation layer 7 as follows. Using a sputtering device, a platinum (Pt) target was used to deposit a platinum film with a thickness of about 200 nm so that the sheet resistance would be 0.6Ω / □ (square).

  A part of the laminated body composed of the porous oxide semiconductor layers 3 and 4, the osmotic layer 7 and the counter electrode layer 8 is mechanically removed to expose the side surface of the osmotic layer 7, and then exposed to the dye solution for 38 hours. It was immersed, and the dye was adsorbed to the porous oxide semiconductor layers 3 and 4 through the permeation layer 7. The dye solution (the dye content is 0.3 mmol / l) was prepared by dissolving the dye ("N719" manufactured by Solaronics SA) in the solvent acetonitrile and t-butanol (1: 1 by volume). .

  Next, the transparent conductive layer 2b made of fluorine-doped tin oxide on the conductive substrate 2 was soldered using ultrasonic waves to form an extraction electrode. Further, an Ag paste was applied to a part of the platinum film constituting the counter electrode layer 8 and heated to form an extraction electrode.

Next, the electrolyte solution was infiltrated into the porous oxide semiconductor layers 3 and 4 through the infiltration layer 7. In Example 1, an electrolyte solution prepared by using iodine (I ₂ ), lithium iodide (LiI), and acetonitrile as liquid electrolytes was used. Next, a sealing material sheet made of an olefin resin was placed on the counter electrode layer 8 and heated to form the sealing portion 9.

When the photoelectric conversion characteristics of the photoelectric conversion device thus obtained were evaluated, the conversion efficiency was 5.4% at AM 1.5 and 100 mW / cm ² .

  As described above, in Example 1, it was confirmed that the photoelectric conversion device of the present invention can be easily produced with a small amount of material and that good conversion efficiency can be obtained.

  Example 2 of the photoelectric conversion device of the present invention will be described below. A photoelectric conversion device 1 having the configuration shown in FIG. 1 was produced as follows.

  First, a glass substrate (3 cm long × 2 cm wide) with a transparent conductive layer made of fluorine-doped tin oxide was used as the conductive substrate 2. A light incident side porous oxide semiconductor layer 3 made of titanium dioxide was formed on the conductive substrate 2. The porous oxide semiconductor layer 3 was formed in the same manner as in Example 1, and the porous oxide semiconductor layer 3 having a thickness of about 7 μm was formed. When the surface of the porous oxide semiconductor layer 3 was measured with a surf test apparatus, Ra of the porous oxide semiconductor layer 3 was Ra = 0.02 μm, and was transparent by visual observation under visible light.

  When the conductive substrate 2 on which the porous oxide semiconductor layer 3 was formed was broken and AFM measurement of the fracture surface of the porous oxide semiconductor layer 3 was performed in the range of 5 μm, Ra = 0.022 μm. A value almost the same as the value measured with the surf test apparatus (Ra = 0.02 μm) was obtained.

Next, the light emitting side porous oxide semiconductor layer 4 made of titanium dioxide was formed on the porous oxide semiconductor layer 3. This porous oxide semiconductor layer 4 was formed as follows. First, 10% by weight of spherical fine particles (average particle size 0.15 μm) of acrylic resin (methacrylic acid ester copolymer) was added to TiO ₂ anatase powder, and then kneaded with deionized water to prepare a liquid paste of titanium oxide. Produced. Next, bubbles of the liquid paste were eliminated with a centrifugal defoamer. This liquid paste is gently dropped onto the porous oxide semiconductor layer 3 and applied by a bar coating method, followed by baking at 450 ° C. for 30 minutes in the air to form a porous oxide semiconductor layer 4 having a thickness of about 5 μm. Formed. When the surface of the porous oxide semiconductor layer 4 was measured for Ra of the porous oxide semiconductor layer 4 with a surf test apparatus, Ra was 0.062 μm, and it was opaque by visual observation under visible light.

  Next, after forming the permeation layer 7 and the counter electrode layer 8 in the same manner as in Example 1 above, the conductive substrate 2 on which the porous oxide semiconductor layers 3 and 4 are formed is formed on the porous oxide semiconductor layers 3 and 4. The photoelectric conversion device 1 was manufactured by adsorbing the dye, forming an extraction electrode, injecting an electrolyte solution, and forming the sealing portion 9.

When the photoelectric conversion characteristics of the photoelectric conversion device 1 thus obtained were evaluated, the conversion efficiency was 5.7% at AM 1.5 and 100 mW / cm ² .

  As described above, in Example 2, the photoelectric conversion device 1 of the present invention can be easily manufactured with a small amount of material, and high conversion efficiency can be realized.

  Example 3 of the photoelectric conversion device of the present invention will be described below. The photoelectric conversion device 1 having the configuration shown in FIG. 2 was produced as follows.

  First, a glass substrate (3 cm long × 2 cm wide) with a transparent conductive layer made of fluorine-doped tin oxide was used as the conductive substrate 2. A light incident side porous oxide semiconductor layer 3 made of titanium dioxide was formed on the conductive substrate 2. The porous oxide semiconductor layer 3 was formed in the same manner as in Example 1, and the porous oxide semiconductor layer 3 having a thickness of about 7 μm was formed. When the surface of the porous oxide semiconductor layer 3 was measured for the surface of the porous oxide semiconductor layer 3 with a surf test apparatus, Ra was 0.021 μm and it was transparent by visual observation under visible light.

Next, an intermediate porous oxide semiconductor layer 5 made of titanium dioxide was formed on the porous oxide semiconductor layer 3. This porous oxide semiconductor layer 5 was formed as follows. First, 5 wt% of acrylic resin (methacrylic acid ester copolymer) spherical fine particles (average particle size 0.15 μm) were added to TiO ₂ anatase powder, and then kneaded with deionized water to prepare a titanium dioxide liquid paste. Produced. Next, bubbles of the liquid paste were eliminated with a centrifugal defoamer. This liquid paste was gently dropped onto the porous oxide semiconductor layer 3 and applied by a bar coating method. Next, the porous oxide semiconductor layer 5 having a thickness of about 4 μm was obtained by baking at 450 ° C. for 30 minutes in the air. When the surface of the porous oxide semiconductor layer 5 was measured for the surface of the porous oxide semiconductor layer 5 with a surf test apparatus, Ra was 0.048 μm, and it was translucent when viewed under visible light.

Next, a light emitting side porous oxide semiconductor layer 4 made of titanium dioxide was formed on the porous oxide semiconductor layer 5. This porous oxide semiconductor layer 4 was formed as follows. First, 10% by weight of spherical fine particles (average particle size: 1.5 μm) of acrylic resin (methacrylic ester copolymer) was added to TiO ₂ anatase powder, and then kneaded with deionized water to prepare a liquid paste of titanium oxide. Produced. Next, bubbles of the liquid paste were eliminated with a centrifugal defoamer. This liquid paste was uniformly applied on the porous oxide semiconductor layer 5 as a liquid paste containing bubbles by spray coating. Next, the porous oxide semiconductor layer 4 having a thickness of about 2 μm was formed by baking at 450 ° C. for 30 minutes in the air. When the surface of the porous oxide semiconductor layer 4 was measured for Ra of the porous oxide semiconductor layer 4 with a surf test apparatus, it was Ra = 0.11 μm, and it was opaque by visual observation under visible light.

  After forming the permeation layer 7 and the counter electrode layer 8 in the same manner as in Example 1 above, the conductive substrate 2 on which the porous oxide semiconductor layers 3 to 5 are formed is dyed on the porous oxide semiconductor layers 3, 4, and 5. Was adsorbed, an extraction electrode was formed, an electrolyte solution was injected, and then a sealing portion 9 was formed to produce a photoelectric conversion device 1 ′.

When the photoelectric conversion characteristics of the photoelectric conversion device 1 ′ thus obtained were evaluated, the conversion efficiency was 6.0% at AM 1.5 and 100 mW / cm ² .

  As described above, in Example 3, the photoelectric conversion device 1 ′ of the present invention can be easily manufactured with a small amount of material, and high conversion efficiency can be realized.

It is sectional drawing which shows an example of embodiment about the photoelectric conversion apparatus of this invention. It is sectional drawing which shows the other example of embodiment about the photoelectric conversion apparatus of this invention. It is a graph which shows the relationship between the arithmetic mean roughness of the surface of a porous oxide semiconductor layer, and the absorption wavelength of the light absorbed by a porous oxide semiconductor layer.

Explanation of symbols

1: Photoelectric conversion device 2: Conductive substrate 2a: Substrate 2b: Transparent conductive layer 3: Light incident side porous oxide semiconductor layer 4: Light emitting side porous oxide semiconductor layer 5: Intermediate porous oxide Semiconductor layer 7: Penetration layer 8: Counter electrode layer 9: Sealing portion

Claims (10)

  A porous oxide semiconductor layer that adsorbs a dye and contains an electrolyte, and a permeation layer and a counter electrode layer in which the electrolyte solution permeates and holds the permeated solution are sequentially formed on the conductive substrate, The porous oxide semiconductor layer is formed by laminating a plurality of layers, and the arithmetic average roughness of the surface of the porous oxide semiconductor layer on the light incident side or the surface of the fracture surface is the porous oxide on the light emitting side. It is smaller than the arithmetic mean roughness of the surface of the semiconductor layer or the surface of the fracture surface, and the thickness of the porous oxide semiconductor layer on the light incident side is thicker than the thickness of the porous oxide semiconductor layer on the light emission side A photoelectric conversion device.   2. The photoelectric conversion device according to claim 1, wherein the arithmetic average roughness of the surface of the permeation layer or the surface of the fractured surface is larger than the arithmetic average roughness of the surface of the porous oxide semiconductor layer or the surface of the fractured surface. .   The photoelectric conversion device according to claim 1, wherein the permeation layer is made of a fired body obtained by firing at least one of insulator particles and oxide semiconductor particles.   4. The photoelectric conversion device according to claim 3, wherein the permeation layer is made of a fired body obtained by firing at least one of aluminum oxide particles and titanium oxide particles.   A sealing member for sealing the electrolyte is formed on the conductive substrate so as to cover an upper surface and a side surface of a laminate in which the porous oxide semiconductor layer, the permeation layer, and the counter electrode layer are sequentially formed. The photoelectric conversion device according to claim 1, wherein:   The porous oxide semiconductor layer formed by laminating a plurality of layers is composed of a sintered body of oxide semiconductor fine particles, and an average of the sintered particles of the oxide semiconductor fine particles forming the porous oxide semiconductor layer on the light emission side. 6. The photoelectric conversion according to claim 1, wherein a particle diameter is larger than an average particle diameter of sintered particles of the oxide semiconductor fine particles forming the porous oxide semiconductor layer on the light incident side. apparatus.   A porous oxide semiconductor layer composed of a sintered body of oxide semiconductor fine particles formed by adsorbing a pigment and containing an electrolyte and laminating a plurality of layers on a conductive substrate, the electrolyte solution penetrating and penetrating A method for manufacturing a dye-sensitized photoelectric conversion device in which a permeation layer for holding a solution and a counter electrode layer are sequentially formed, and oxidation of each porous oxide semiconductor layer formed by stacking a plurality of layers The average particle diameter of the primary particles before sintering of the semiconductor fine particles is the same, the porous oxide semiconductor layer on the light incident side is dispersed, the dispersed phase is the primary particles of the oxide semiconductor fine particles, and the dispersion medium is liquid. The colloidal liquid paste is applied and baked to form the porous oxide semiconductor layer on the light emitting side by applying and baking an aerosol obtained by adding a gas as a dispersion medium to the liquid paste. To the above After the permeation layer is formed on the porous oxide semiconductor layer, the electrolyte solution is passed through the permeation layer of the laminate formed by forming the porous oxide semiconductor layer and the permeation layer on the conductive substrate. A method for producing a photoelectric conversion device, characterized in that it is permeated.   A porous oxide semiconductor layer composed of a sintered body of oxide semiconductor fine particles formed by adsorbing a pigment and containing an electrolyte and laminating a plurality of layers on a conductive substrate, the electrolyte solution penetrating and penetrating A method for manufacturing a dye-sensitized photoelectric conversion device in which a permeation layer for holding a solution and a counter electrode layer are sequentially formed, and oxidation of each porous oxide semiconductor layer formed by stacking a plurality of layers The average particle diameter of the primary particles before sintering of the semiconductor fine particles is the same, the porous oxide semiconductor layer on the light incident side is dispersed, the dispersed phase is the primary particles of the oxide semiconductor fine particles, and the dispersion medium is liquid. The colloidal liquid paste is applied and baked, and the porous oxide semiconductor layer on the light emitting side is applied and baked by applying a liquid paste in which fine particles of organic resin are added as a dispersed phase to the liquid paste. form Then, after the penetration layer is formed on the porous oxide semiconductor layer, the porous oxide semiconductor layer and the penetration layer are formed on the conductive substrate. A method for manufacturing a photoelectric conversion device, wherein the electrolyte solution is infiltrated.   A porous oxide semiconductor layer composed of a sintered body of oxide semiconductor fine particles formed by adsorbing a pigment and containing an electrolyte and laminating a plurality of layers on a conductive substrate, the electrolyte solution penetrating and penetrating A method for manufacturing a dye-sensitized photoelectric conversion device in which a permeation layer for holding a solution and a counter electrode layer are sequentially formed, and oxidation of each porous oxide semiconductor layer formed by stacking a plurality of layers The average particle diameter of the primary particles before sintering of the semiconductor fine particles is the same, the porous oxide semiconductor layer on the light incident side is dispersed, the dispersed phase is the primary particles of the oxide semiconductor fine particles, and the dispersion medium is liquid. The colloidal liquid paste is applied and baked to form the porous oxide semiconductor layer on the light emitting side, and fine particles of organic resin are added to the liquid paste as a dispersed phase and gas is added as a dispersion medium. An aerosol is applied and fired, and then the permeation layer is formed on the porous oxide semiconductor layer, and then the porous oxide semiconductor layer and the permeation layer are formed on the conductive substrate. A method for manufacturing a photoelectric conversion device, wherein the electrolyte solution is permeated through the permeation layer of the laminate. 7. A photovoltaic power generation apparatus characterized in that the photoelectric conversion device according to claim 1 is used as a power generation means, and the power generated by the power generation means is supplied to a load.

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