Dye sensitized solar cell and dye-sensitized solar cell module

Abstract

A dye-sensitized solar cell formed by layering a conductive layer; a photoelectric conversion layer in which a dye is adsorbed in a porous semiconductor layer and the layer is filled with a carrier transporting material; and a counter electrode including only a counter electrode conductive layer or including a catalyst layer and a counter electrode conductive layer on a support made of a light transmitting material,in which the photoelectric conversion layer is brought into contact with the counter electrode; the porous semiconductor layer forming the photoelectric conversion layer has two or more layers with different light scattering properties; and the two or more porous semiconductor layers are layered in an order of from a layer with lower light scattering property to a layer with higher light scattering property from a light receiving face side of the dye-sensitized solar cell.

Description

TECHNICAL FIELD[0001]The present invention relates to a dye-sensitized solar cell and a dye-sensitized solar cell module.BACKGROUND ART[0002]As an energy source in place of fossil fuel, solar cells capable of converting sun light to electric power have drawn attention. Presently, some of solar cells using crystalline silicon substrates and thin film silicon solar cells have been used practically. However, the former has a problem of a high production cost of the silicon substrates and the latter has a problem that the production cost is increased since various kinds of gases for semiconductor production and complicated production facilities are required. Therefore, in both solar cells, it has been tried to lower the cost per electric power output by increasing the efficiency of photoelectric conversion; however, the above-mentioned problems still remain while being unsolved.[0003]As a new type solar cell, there has been proposed a wet type solar cell based on photo-induced electron ...

AI Technical Summary

Benefits of technology

[0034]According to the present invention, it is possible to provide a high performance dye-sensitized solar cell having an improved FF and an enhanced short-circuit current and a dye-sensitized solar cell module using the cell at low cost.

[0035]In the present invention, since at least two porous semiconductor layers with different light scattering properties are layered in an order of from a layer with lower light scattering property to a layer with higher light scattering property from a light receiving face side of the dye-sensitized solar cell, incident light can efficiently be utilized for photoelectric conversion and a particle diameter of semiconductor particles forming the porous semiconductor layer on an opposite side of the light receiving face is increased. Since the amount of the dye adsorbed in such a porous semiconductor layer is small, the incident light is only absorbed and reflected by the semiconductor particles. In the case where the porous semiconductor layer contains titanium oxide particles, the light absorption region is about 400 nm or shorter and the incident light is absorbed by a carrier transporting material, in which redox seeds such as the titanium oxide particles of the porous semiconductor layer in the light receiving face side and iodine are dissolved, and scarcely reaches the porous semiconductor layer on the opposite side of the light receiving face.

[0036]Accordingly, in the above-mentioned configuration, due to difference of the basic energy levels, no leakage occurs and photoelectric conversion is not dominantly caused in the interface of the photoelectric conversion layer and the catalyst layer, where the leakage is expected to occur, and therefore a porous insulating layer may not be formed. However, in the case of a dye-sensitized solar cell module, the dye-sensitized solar cell of the present invention having no porous insulating layer and a conventional dye-sensitized solar cell having a porous insulating layer may be combined.

Problems solved by technology

However, the former has a problem of a high production cost of the silicon substrates and the latter has a problem that the production cost is increased since various kinds of gases for semiconductor production and complicated production facilities are required.

Therefore, in both solar cells, it has been tried to lower the cost per electric power output by increasing the efficiency of photoelectric conversion; however, the above-mentioned problems still remain while being unsolved.

However, since a basic structure of the dye-sensitized solar cell described in Patent Document 1 is a structure that the electrolytic solution is injected between the opposed transparent conductive film-bearing glass substrates, it is possible to produce a trial solar cell with a small surface area, but it is difficult to practically produce a solar cell with a large surface area such as 1 m square.

As a result, FF (fill-factor) and a short circuit current at the time of the photoelectric conversion are lowered, resulting in a problem of decrease of the photoelectric conversion efficiency.

Further, since the dye-sensitized solar cell module is produced by forming elements between the opposed transparent conductive film-bearing glass substrates, the module has problems that the production cost is increased and the weight is increased.

However, the dye-sensitized solar cell modules described in Patent Document 2 and Non-Patent Document 1 have a configuration that a basic structure of each dye-sensitized solar cell is formed by injecting the electrolytic solution between the opposed transparent conductive film-bearing glass substrates, and therefore the problems of the production cost and weight still remain while being unsolved.

Therefore, the processing steps are increased and the transportation resistance of a carrier transporting material is increased due to the formation of the porous insulating layer, resulting in a problem of deterioration of the performance of the solar cell.

However, if the porous semiconductor layer and the catalyst layer are formed using fine particles, the physical values (energy levels and Schottky barrier between two type materials) of the respective materials cannot often be applied as they are.

Images