JP3441361B2 - Photoelectric conversion element - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a photoelectric conversion element such as a solar cell.

[0002]

2. Description of the Related Art In recent years, photoelectrochemical cells called Grazel cells have been expected as inexpensive and highly efficient solar cells. As shown in FIG. 5, the Grazel cell generally includes a transparent electrode 42 formed on a light-transmissive substrate 41 such as glass and a titanium dioxide carrying a sensitizing dye formed on the transparent electrode 42. Metal oxide semiconductor layer 43
And an electrolyte layer 46 formed between a rear wall which is a counter electrode 45 formed on the light transmissive substrate 44, and has a laminated structure.

In such a Grazel cell, light 48 such as sunlight is incident from the side of the light transmissive substrate 41, passes through the transparent electrode 42, reaches the semiconductor layer 43, and generates electricity by photoelectrochemical reaction. Therefore, in such a cell structure, the transparent electrode 42 having high light transmittance is indispensable in order to obtain good incident light intensity to the semiconductor layer 43, but a general transparent electrode made of a metal oxide. Has insufficient conductivity as compared with an electrode made of metal or carbon. Therefore, in the cell using the transparent electrode, the internal resistance was increased, and the output current and the photoelectric conversion efficiency could not be sufficiently increased.

Further, in order to increase the light utilization efficiency, it is necessary to increase the layer thickness of the semiconductor layer 43 which is a light absorption layer to increase the optical path length in the film. However, if the optical path length in the film is increased. At the same time, the distance between the transparent electrode 42 and the counter electrode 45 is increased. Therefore, there is a problem in that the photoelectric conversion efficiency is reduced as in the case described above.

In many cases, a paste in which semiconductor particles are dispersed is squeegee printed on the surface of the transparent substrate 41 on which the transparent electrode 42 is formed, and then the paste is baked to sinter the semiconductor particles to form a semiconductor layer. 43 is formed. At this time, it has to be sintered at a certain high temperature, for example,
In the case of titanium dioxide, sintering is performed at about 450 ° C. Therefore, the light transmissive substrate 41 needs to have heat resistance and, for example, an inexpensive resin light transmissive substrate or the like cannot be used.

In addition, in the case of the conventional parallel plate electrode, it is difficult to keep the inter-electrode spacing between the transparent electrode 42 and the counter electrode 45 constant, especially when the area is increased, and the variation of the inter-electrode spacing in the plane. Caused a decrease in efficiency.

[0007]

As described above, in the conventional laminated structure type Grazel cell, the internal resistance is high because the transparent electrode which does not have sufficient conductivity is used.
The photoelectric conversion efficiency and output current could not be increased. Further, since the inter-electrode distance between the anode and the cathode is increased, the optical path length of the incident light in the semiconductor layer cannot be increased and the light utilization efficiency is poor. Further, since the light transmissive substrate needs to have heat resistance, an inexpensive resin substrate having insufficient heat resistance cannot be used. Further, it is difficult to keep the distance between the electrodes in the plane constant, which is one of the causes for lowering the photoelectric conversion efficiency.

[0008] The conventional photoelectric conversion device having the laminated structure has many problems as described above, and at present, no device capable of avoiding all of these problems has been obtained. Therefore, the present invention secures a sufficient incident light intensity to the semiconductor layer without using a transparent electrode that increases the internal resistance of the cell, and does not increase the inter-electrode spacing between the anode and the cathode. An object is to provide a high-efficiency photoelectric conversion element in which an optical path length of incident light in the inside can be increased, an inexpensive resin substrate can be used as a light-transmitting substrate, and an interval between electrodes is constant. And

[0009]

In order to solve the above-mentioned problems, the present invention provides a substrate having at least one surface which is insulative, and an electrode having a first polarity formed on the insulative surface of the substrate. A pair of electrodes composed of electrodes of a second polarity, a semiconductor layer carrying a dye formed on the electrodes of the first polarity in contact with the electrodes of the first polarity, and the electrodes of the second polarity; There is provided a photoelectric conversion device comprising a charge transport layer formed between the semiconductor layer and an ion conductive material or a hole conductive material.

Further, according to the present invention, a substrate having at least one surface which is insulative, a first polarity electrode formed on the insulative surface of the substrate, and an electrode formed on the first polarity electrode And a charge transport layer containing an ion conductive substance or a hole conductive substance, and a porous semiconductor layer formed on the charge transport layer and having a second polar electrode in the form of a porous sheet embedded therein. The photoelectric conversion element is characterized in that the porous sheet-shaped second polarity electrode includes continuous pores having openings on the front surface and the back surface, and the porous semiconductor layer carries a dye. .

The present invention will be described in detail below. In Figure 1,
FIG. 2 is a sectional view schematically showing an example of the first photoelectric conversion element of the present invention. As shown in the figure, in the first photoelectric conversion element 10 of the present invention, a pair of electrodes consisting of an electrode 12a of the first polarity and an electrode 12b of the second polarity is formed on the substrate 11, and A semiconductor layer 13 having p-type or n-type conductivity is formed on the top. Here, the surface of the substrate 11 on which the pair of electrodes is formed is insulative.
The semiconductor layer 13 is provided only in contact with the first polarity electrode 12a of the pair of electrodes.
The conductivity type of the semiconductor layer 13 is determined according to the polarity of 2a. On the other hand, a charge transport layer 14 containing an ion conductive material or a hole conductive material is formed between the second polarity electrode 12b and the semiconductor layer 13.

In the photoelectric conversion element of the first invention, the first
The substrate 11 on which a pair of electrodes composed of an electrode having the above polarity and an electrode having the second polarity is formed is not particularly limited as long as the surface on which the electrodes are formed has a good insulating property. Absent. For example, the entire substrate may be made of an insulating material. In this case, specifically, a glass substrate; F
Examples thereof include organic polymer substrates such as RP; ceramic substrates such as alumina and aluminum nitride; silicon substrates.

Even when the material is not a non-conductive material, it can be used as a substrate in the photoelectric conversion element of the present invention by coating the surface on which the electrode is formed with an insulating material such as polymer, glass, or ceramic. .
By applying such a coating, a metal substrate such as stainless steel, aluminum, and titanium, a carbon substrate, or the like can be used.

When the substrate is light-transmissive, the back surface of the substrate is
A coating for reflecting transmitted light may be formed. For example, an aluminum thin film or the like is deposited by a vapor deposition method or a sputtering method in a range of 0.05-1
By using a film thickness of about μm, it is possible to improve the light utilization efficiency. Alternatively, a reflective film of such a metal may be formed on the upper surface of the substrate, and a transparent insulating film may be formed thereon.

Any material can be used as the material of the electrode formed on the substrate as long as it is a conductive substance. The materials forming the first polarity electrode and the second polarity electrode may be the same or different. However, when the charge transport layer formed on the second polarity electrode is the electrolyte layer, it is preferable to use a material that is electrochemically stable as the electrode. Specifically, platinum, gold, It is desirable to use carbon and the like. When other conductive materials such as aluminum, copper, iron, stainless steel, titanium, silver, doped polyaniline, polypyrrole, and polythiophene are used as electrodes, only the surface in contact with the electrolyte layer is platinum or gold. By covering with carbon or the like, the same stability as described above can be obtained. Such coating is performed, for example, by forming electrodes in a desired pattern and then coating platinum, gold, or the like by electrolytic or electroless plating. The surface of the electrode is preferably in a state where the surface area is increased by the fine structure. For example, it is desirable that platinum is in a platinum black state and carbon is in a porous state. The platinum black state can be formed by a method such as anodic oxidation of platinum, and the porous carbon can be formed by a method such as sintering of carbon fine particles or firing of an organic polymer.

In particular, titanium can form titanium dioxide capable of forming a semiconductor layer by anodic oxidation. Therefore, in the case of porous titanium having a titanium dioxide layer formed on the surface as described above, platinum is formed on the outermost surface. It is not necessary to form an electrochemically stable layer such as a membrane.

In the first photoelectric conversion element of the present invention having the above-mentioned structure, the pattern shapes of the first polarity electrode 12a and the second polarity electrode 12b are not particularly limited. Here, an example of the pattern shape of the electrodes is shown in FIG. In FIG. 2, lead wires connected to the first polarity electrode 12a and the second polarity electrode 12b are not shown.

For example, stripe type (FIG. 2A), comb type (FIG. 2B), concentric type (FIG. 2C), spiral type (FIG. 2D), and spot type (FIG. 2 (e), (f))
Are used well. Among these pattern shapes, in particular, in the case of forming a pattern in which units each including a plurality of comb-shaped electrodes are connected in series, a photoelectric conversion panel capable of outputting a high voltage can be easily manufactured.

Adjacent first polarity electrode 12a and second electrode
If the inter-electrode distance between the polar electrodes 12b (for example, the distance indicated by d in the figure) is large, the internal resistance of the photoelectric conversion element increases. Therefore, since it is necessary to form the semiconductor layer,
The distance d between the electrodes is preferably 2 μm or more. The distance between the electrodes is more preferably 10 to 200 μm, and most preferably 20 to 50 μm.

In the first polarity electrode 12a and the second polarity electrode 12b, it is preferable that the ratio of the height of the electrode to the width of the electrode (height / width, hereinafter referred to as aspect ratio) is large. When an electrode having a large aspect ratio is used, it is possible to increase the optical path length of incident light in the semiconductor layer without increasing the distance between the electrodes. The aspect ratio of the electrodes in the photoelectric conversion element of the present invention is preferably 0.5 or more. The aspect ratio of the electrode is more preferably 2 or more, and most preferably 3 or more.

Such an electrode group can be formed by using a microlithography technique such as etching using a resist (including a dry film) as a mask. Alternatively, it may be formed by screen printing or the like. Further, the aspect ratio of the electrodes may be increased by further plating on the conductive pattern thus formed. Electroplating using a resist pattern during plating makes it easy to obtain an electrode shape with a high aspect ratio.

The lead wire portion (current collecting portion) connected to the first polarity electrode and the second polarity electrode, that is, the pattern electrode group consisting of the anode electrode and the cathode electrode, has an anode electrode and a collector electrode like a comb pattern. It may be formed integrally with the cathode electrode in the same plane. Alternatively,
As shown in FIG. 3, the lead wire portion 18 may be formed on the back surface of the insulating substrate 1 by being connected to the anode 12 a and the like via the conductive through hole 19. In general, the lead wire portion does not have a photoelectric conversion function, or even if it has a photoelectric conversion function, it is very weak. Therefore, it is desired that only the anode and the cathode are present on the incident light irradiation surface. The multilayer wiring structure using the through holes 19 as shown in FIG. 3 is preferable because the photoelectric conversion region formed by the pattern of the anode and the cathode can be widened.

In the photoelectric conversion device of the present invention, when the electrode of the first polarity is the anode electrode, the conductivity type of the semiconductor layer directly formed thereon is n-type. In this case n
The type semiconductor may be any of a metal oxide semiconductor and a metal compound semiconductor. The absorption region of the sensitizing dye carried is preferably transparent or nearly transparent. For example, as a metal oxide semiconductor, a transition metal or a group 4 or 5
Elements of group 3 or 6 sub-group, especially titanium, zirconium, hafnium, strontium, zinc, indium,
Examples thereof include oxides such as yttrium, lanthanum, vanadium, niobium, tantalum, chromium, molybdenum, and tungsten, and perovskites. These semiconductors may be used in any state of amorphous, polycrystal, or single crystal. However, in order to increase the amount of dye supported, the semiconductor layer used in the present invention is desired to be porous and have a large surface area.

The dye to be supported on the n-type semiconductor may be any dye as long as it has absorption in the visible light region and can inject an electron into the semiconductor layer by a photoexcitation reaction, and a transition metal complex or the like is used. Specific examples thereof include metal complexes such as ruthenium, osmium, and iron. In particular, when the ligand is a bidentate, tridentate or whole-dentate polypyridyl compound and has a substituent capable of binding to a hydroxyl group on the surface of titanium dioxide such as a carboxyl group, the amount of dye carried can be increased. It is preferable because the efficiency of electron transfer from the dye to the semiconductor layer can be improved.

On the other hand, when the electrode of the first polarity is the cathode, the conductivity type of the semiconductor layer formed directly thereon is p.
Use as a mold. In this case, the p-type semiconductor is not particularly limited, but it is preferably transparent or nearly transparent in the absorption region of the sensitizing dye to be carried. Specifically, for example, CuAlO ₂
A transparent transition metal composite oxide such as is preferably used.

As the dye to be carried on the p-type semiconductor layer,
Any substance having absorption in the visible light region and capable of injecting holes into the semiconductor layer by a photoexcitation reaction may be used, and various transition metal complexes, metal phthalocyanines, polycyclic aromatics, charge transfer complexes, etc. may be used. Used. Specific examples include porphyrins, perylenes, coronene, fullerenes, and tetracyanoquinodimethanes. In particular, a dye in which a bonding group with a semiconductor such as a carboxyl group or a hydroxyl group is introduced into these dyes is preferable from the viewpoint that the amount supported on the semiconductor can be increased and the injection of holes can proceed smoothly.

From the viewpoint of durability and cost, titanium oxide which is an n-type semiconductor is preferable. In addition, it is preferable that both the n-type and the p-type are porous bodies having continuous pores of the order of several tens of nanometers because the amount of dye carried is large and the charge transport is smoothly performed.

As described above, a semiconductor layer of a predetermined conductivity type is formed on a pair of electrodes so as to come into contact with the first polarity electrode. In the photoelectric conversion element of the present invention, this semiconductor layer A charge transport layer is formed between the second polarity electrode and the second polarity electrode.

The charge transport layer contains an ion conductive material or a hole conductive material. An electrolyte solution containing a reversible redox couple such as iodide, bromide, and hydroquinone as the ion conductive material; a polymer gel electrolyte impregnated with an electrolyte solution using a crosslinked polyacrylic resin derivative or a crosslinked polyacrylonitrile derivative as a matrix; Polymer electrolytes obtained by dissolving an electrolyte in polyalkylene oxides, silicone resins and the like; molten salt electrolytes such as polymer ammonium salts.

In the case of the electrolyte solution, an inorganic porous material such as porous silica, alumina, rutile phase titanium dioxide having a sufficient porosity, or a porous material of an organic substance such as poly (vinylidene fluoride). It may be used in a state of being impregnated with.

As the hole conductive material, for example,
Amorphous materials such as triallylamines; Polymeric hole-transporting materials such as polyvinylcarbazole; Conjugated polymers such as polyphenylene, polyphenylenevinylene, polythiophene, polypyrrole, polyaniline, polysilole, polysilane: or their derivatives are used. .

Since the photoelectric conversion element of the present invention may be deteriorated when moisture or oxygen penetrates into the inside, it is preferable that the photoelectric conversion element is well sealed. Therefore, as shown in FIG. 1, it is necessary to cover the semiconductor layer 13 with a light-transmissive substrate 15 such as a glass plate or a resin plate, and to seal the end face with a sealant 16 made of epoxy resin, silicon resin or the like. Is desired.

The light-transmitting substrate is not particularly limited in its material as long as it has light-transmitting properties and a barrier ability against moisture and oxygen, and for example, a resin film can be used. . Further, instead of sticking the film, a coating liquid such as a resin may be applied onto the semiconductor layer for sealing. Alternatively, the entire cell may be integrally molded and sealed by using a molding method using resin or the like, an injection molding method, or the like, similarly to the case of sealing the semiconductor chip with the sealing resin. Furthermore, the cell can be sandwiched between two resin films from above and below for lamination. In this case, the resin films above and below the end faces may be fused and sealed.

As the resin substrate and the resin film, those whose surface is coated with silica to suppress the permeation of moisture and oxygen are preferable. From the viewpoint of improving the sealing in this way, it is preferable to use, as the substrate on which the electrodes are formed, a substrate excellent in the moisture and oxygen shielding property. The charge transport layer and the semiconductor layer formed on the substrate may significantly deteriorate in performance due to contamination such as trace impurities eluted from the substrate. Therefore, in order to avoid such a decrease in performance, a ceramic substrate having excellent moisture and oxygen shielding properties and less elution of impurities is excellent. For substrates such as sodium glass substrates and metal substrates where metal ions and other impurities are likely to elute, a passivation film such as a ceramic coating or silica coating is formed on the surface to prevent elution of impurities. Can be used for.

In the photoelectric conversion element 10 shown in FIG. 1, at the interface between the semiconductor layer 13 and the light transmissive substrate 15,
A transparent electrode layer or a light-transmissive sheet-shaped conductive layer such as a conductive polymer film, a metal mesh, or a metal stripe may be provided as an auxiliary electrode of the anode.

As described above, in the first photoelectric conversion element of the present invention, since the pattern electrode of the first polarity and the pattern electrode of the second polarity are formed on the same substrate,
It is possible to increase the optical path length of incident light in the semiconductor layer without increasing the inter-electrode spacing, which is a cause of efficiency reduction. For this reason, the utilization efficiency of incident light is increased, and the photoelectric conversion efficiency can be improved. Furthermore, since it is not necessary to use a transparent conductive film having a relatively high sheet resistance value, the internal resistance of the photoelectric conversion element is reduced, and even when the area is increased or the incident light intensity is high, photoelectric conversion by charge-up is performed. It is possible to prevent a decrease in efficiency and increase a current value that can be taken out.

Moreover, since an inexpensive light-transmissive substrate made of resin or the like can be used and the inter-electrode spacing is kept constant by the electrode pattern such as a comb shape, the substrate can be made different from the conventional parallel plate type cell. All of the inconveniences caused by the bending and the like are eliminated. That is, the deflection of the substrate does not cause non-uniformity of the inter-electrode spacing, which does not reduce the photoelectric conversion efficiency. In addition, multiple comb-shaped anodes /
By forming an electrode pattern in which units each composed of a pair of cathodes are connected in series, a high-efficiency photoelectric conversion element capable of easily outputting a high voltage can be provided.

FIG. 4 is a sectional view schematically showing an example of the second photoelectric conversion element of the present invention. As shown,
In the second photoelectric conversion element 30 of the present invention, the substrate 31
An electrode 32 of the first polarity and a charge transport layer 33 are sequentially formed on the top. The charge transport layer 33 here contains an ion conductive material or a hole conductive material.
Further, on the charge transport layer 33, a porous semiconductor layer 35 in which a porous sheet-shaped second polarity electrode 34 is embedded is provided. The porous sheet-shaped second polarity electrode 34 includes continuous pores having openings on both the front surface and the back surface, and the dye is carried in the porous semiconductor layer 35. The conductivity type of the semiconductor layer 35 is determined according to the polarity of the electrode 34.

In the second photoelectric conversion element 30 of the present invention, the substrate 31 on which the electrode 32 of the first polarity is formed is particularly limited as long as the surface on which the electrode is formed has a good insulating property. Not a thing. For example, the entire substrate may be made of an insulating material, and in this case, specifically, a glass substrate; an organic polymer substrate such as FRP; a ceramic substrate such as alumina and aluminum nitride; a silicon substrate and the like. .

Even if it is not a non-conductive material, it can be used as a substrate in the photoelectric conversion element of the present invention by coating the surface on which the electrode is formed with an insulating material such as polymer, glass or ceramics. .
By applying such a coating, a metal substrate such as stainless steel, aluminum, and titanium, a carbon substrate, or the like can be used.

The material of the first polarity electrode formed on such a substrate is not particularly limited, and any material can be used as long as it is a conductive substance. Further, various conductive materials as described in the photoelectric conversion element of the first invention may be used.

The charge transport layer 33 formed on the first polarity electrode 32 can be formed using the material as described in the photoelectric conversion element of the first invention.
In the second photoelectric conversion element of the present invention, the porous semiconductor layer 3 in which the porous sheet-shaped second polarity electrode 34 is embedded
5 is formed on the charge transport layer 33.

The term "porous sheet" means that it has continuous pores having openings on the front and back surfaces, and preferably has a porosity of 50% or more, more preferably 80% or more. It means that it has voids of several tens nm or more capable of filling the semiconductor layer, and the porous semiconductor layer means that it has continuous pores of at least several tens nm. The porosity is preferably 10% or more.

The porous sheet-shaped second polarity electrode 34 is
It can be formed from a porous body of carbon or metal. As such a porous material, for example, a material obtained by processing a solid metal plate or the like by a method such as etching is used. Alternatively, a cloth or non-woven fabric formed from carbon or metal fine fibers may be used. Also, for example, a thin film of metal or carbon is electrolytically plated on the surface of a porous body made of resin or ceramics,
Formed by methods such as electroless plating, electrodeposition, vapor deposition,
It is also possible to use a porous sheet-shaped second polarity electrode.

The outermost surface of such a porous body is desired to be electrochemically stable, and platinum, gold, etc. are preferably used. That is, the portion other than the surface, which is the base, is not particularly limited as long as it is a conductive material, aluminum, copper,
Various metals such as iron and stainless steel, and conductive polymers such as doped polypyrrole, polythiophene, polyaniline, etc. can also be used. As long as the outermost surface is an electrochemically conductive material, it is the part that is the base Does not need to be particularly conductive.

Since titanium can form titanium dioxide capable of forming a semiconductor layer by anodic oxidation, in the case of porous titanium having a titanium dioxide layer formed on the surface as described above, a platinum film is formed on the outermost surface. The formation of an electrochemically stable layer such as is not particularly necessary.

The above-mentioned porous sheet-shaped second-polarity electrode 34
As the semiconductor layer 35 formed on the surface of, the same one as that used in the first photoelectric conversion element of the present invention described above can be used.

In the second photoelectric conversion element of the present invention, when the second polarity electrode is used as the anode electrode, the conductivity type of the semiconductor layer in which the porous sheet-shaped second polarity electrode is embedded is N-type. In this case, as the n-type semiconductor and the dye carried therein, those described above can be used.

The semiconductor layer in which the porous sheet-shaped anode electrode is embedded can be obtained, for example, by forming a semiconductor layer on the surface of the porous sheet-shaped anode electrode. Alternatively, a method of forming a mixture of conductive fine particles and semiconductor fine particles may be used. For example, first, a paste prepared by dispersing a mixture containing conductive fine particles such as fluorine-doped tin oxide and semiconductor fine particles such as titanium oxide is applied onto a light-transmissive substrate by a squeegee printing method, Bake the coating. Instead of the light-transmissive substrate, it may be applied on a charge transport layer or a porous layer serving as a spacer layer that can be impregnated with a charge transport material, and then baked. Then, the conductive fine particles and the semiconductor fine particles each cause a percolation to form a bicontinuous structure (co-continuous structure) including a continuous conductive phase and a semiconductor phase. Such a continuous conductive phase can be favorably used as the porous sheet-shaped anode electrode in the photoelectric conversion device of the second invention. In this case, even if a transparent conductive material such as tin oxide having a relatively high resistance is used, it is possible to increase the substantial film thickness of the conductive layer as compared with the sputtering film, etc. The conductivity of can be secured.

In the second photoelectric conversion element of the present invention, when the second polarity electrode is used as the cathode, the conductivity type of the semiconductor layer in which the porous sheet-shaped second polarity electrode is embedded is p.
Use as a mold. In this case, as the p-type semiconductor and the dye carried therein, those described above can be used.

As shown in FIG. 4, in the second photoelectric conversion element 30 of the present invention, the surface on the light incident side (semiconductor layer upper surface) is covered with the light transmissive substrate 36 and sealed. Is preferred. By providing the light transmissive substrate 36 in this manner, it is possible to prevent the evaporation of the electrolyte solvent and the invasion of moisture, oxygen and the like into the cell. As the light transmissive substrate, any material can be used as long as it can satisfactorily transmit the light absorption wavelength of the sensitizing dye supported on the porous semiconductor and can suppress the permeation of gases such as moisture, oxygen, and solvent vapor. For example, a glass plate, a transparent resin film or the like can be used.

The light transmissive substrate can be formed by the method as described for the first photoelectric conversion element. As described above, in the second photoelectric conversion element of the present invention, a carbon or metal electrode having good conductivity can be used as an electrode such as an anode, and a transparent conductive film having a relatively high sheet resistance can be used. No need to use. Therefore, as in the case of the first photoelectric conversion element described above, the internal resistance of the photoelectric conversion element is reduced, and even when the area is increased or the incident light intensity is high, the decrease in photoelectric conversion efficiency due to charge-up is prevented. can do.

In the conventional parallel plate electrode type cell structure, since it is necessary to form the semiconductor layer at a high temperature on the transparent electrode layer formed on the light transmissive substrate, it is inexpensive but heat resistant. It was not possible to use a resin substrate or a resin film that does not have it as a light transmissive substrate.

On the other hand, in the second photoelectric conversion device of the present invention, for example, as described above, the porous layer which is the charge transport layer or the porous layer which becomes the spacer layer which can be impregnated with the charge transport material is provided with the porous first layer. Since the semiconductor layer in which the bipolar electrode is embedded can be formed and then baked, the light transmissive substrate does not necessarily have to be heat resistant. Therefore, the present invention makes it possible for the first time to use an inexpensive resin substrate or resin film as the substrate.

[0055]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in more detail below by showing Examples and Comparative Examples of the present invention, but the present invention is not limited to these Examples. (Example 1) First, on the surface of a glass substrate having a thickness of 1 mm,
A silica coating having a thickness of about 0.1 μm was applied by a dip coating method using a sol-gel solution.

An electrode width of 40 μm was formed in a region of 10 × 10 cm on the glass substrate on which the silica coating was thus formed.
m, the electrode spacing was 40 μm, the electrode length was 10 cm, and the film thickness was 1 μm, and a comb-shaped metal electrode pattern was formed by a screen printing method. Further, copper plating with a film thickness of 20 μm and platinum plating with a film thickness of 1 μm were sequentially applied on this electrode pattern to form a comb-shaped electrode composed of an anode and a cathode.

Next, the glass substrate on which the comb-shaped electrode was formed was dipped in a suspension in which silica particles (average particle diameter 1 μm) were suspended, and the cathode was electrified to have a thickness of 5 μm on the cathode. The silica particle layer was electrodeposited. This silica particle layer is impregnated with an electrolyte solution in a later step to form a charge transport layer.

After electrodeposition and deposition, a titanium dioxide paste containing titanium dioxide fine particles (average particle diameter 20 nm) was applied to the entire surface of the glass substrate having electrodes so that the film thickness on the anode was 10 μm, and 450 The titanium dioxide layer was formed by firing at ℃. After calcination, (cis-di (thiocyanato) -N, N-bis (2,2'-dipyridyl-4,
4′-dicarboxylic acid) -ruthenium (II) dihydrate) in ⁴ × 3 × 10 ⁻⁴ M dry ethanol solution (temperature about 80 ° C.)
Soak for hours. After that, the ruthenium complex was supported on the titanium dioxide layer by pulling it up under an argon stream to form a semiconductor layer.

After drying with ethanol, a glass plate cover as a light-transmissive substrate was covered on the semiconductor layer, and the periphery was sealed with an epoxy resin, leaving an electrolyte injection port. From the inlet, (tetrapropylammonium iodide) = 0.5M, (potassium iodide) = 0.02M, [I ₂ ] = 0.03M acetonitrile / ethylene carbonate mixed solvent (volume ratio 10/9
0) The solution was injected under reduced pressure, and the above silica particle layer was impregnated with this solution to form a charge transport layer.

Finally, the injection port was sealed with an epoxy resin to prepare the photoelectric conversion element of Example 1 (element 1). For comparison, on a conductive glass substrate (fluorine-doped SnO ₂ overcoating, visible light transmittance 85%, sheet resistance 80Ω) having the same size as the glass substrate used above,
The same titanium dioxide paste as described above was applied so that the film thickness on the anode was 10 μm, and the paste was baked at 450 ° C. to form a titanium dioxide layer.

This was treated with (cis-di (thiocyanato) -N,
It was immersed in a 3 × 10 ⁻⁴ M dry ethanol solution of N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) dihydrate (temperature: about 80 ° C.) for 4 hours. Then, the ruthenium complex was supported on the titanium dioxide layer by pulling it up in an argon stream to form a semiconductor layer.

Next, silica particles (average particle diameter 1 μm)
The paste in which was suspended was applied onto the semiconductor layer to form a porous silica particle layer having a thickness of 2 μm. On the other hand, a platinum film was formed on a separately prepared glass substrate by a sputtering method to prepare a cathode plate, and after covering it on the silica particle layer described above, the periphery was sealed with epoxy resin leaving an electrolyte solution inlet. did. From the inlet, (tetrapropylammonium iodide) = 0.5M, (potassium iodide) = 0.02M,
A [I ₂ ] = 0.03 M acetonitrile / ethylene carbonate mixed solvent (volume ratio 10/90) solution was injected, and this solution was impregnated into the silica particle layer to form a charge transport layer.

Finally, the injection port was sealed with an epoxy resin to prepare a photoelectric conversion element (element 2) of Comparative Example 1. Regarding the element 1 and the element 2 obtained as described above,
The photoelectric conversion efficiency was measured using AM1.5 pseudo sunlight (intensity 100 mW) as a light source.

As a result, in element 1, it was 11.3%,
The element 2 has 7.1%, which is higher than that of the laminated photoelectric conversion element 2 using the conventional transparent conductive electrode, and the element 1 using the comb-shaped electrode of the present invention has high photoelectric conversion efficiency. Was given.

Example 2 Example 1 was repeated except that an aluminum vapor-deposited film for reflecting transmitted light was formed on the back surface of the glass substrate on which the comb-shaped electrode was formed, and the platinum electrode surface was made into a platinum black state by the anodic oxidation method. Element 1 and element 2 were produced in the same manner as in.

Regarding the elements 1 and 2 obtained as described above, AM1.5 pseudo sunlight (intensity 100 m
The photoelectric conversion efficiency was measured using W) as a light source.
As a result, element 1: 11.9% and element 2: 5.2% were obtained, which is an element using the comb-shaped electrode of the present invention as compared with the conventional laminated photoelectric conversion element 2 using a transparent conductive electrode. 1 is
High photoelectric conversion efficiency was obtained.

In the case of the element 1 of the present invention, the incident light transmitted through the element is reflected by the aluminum reflection film and again enters the element from the back surface of the substrate, so that the light utilization efficiency is improved. On the other hand, in the element 2, since the back surface of the substrate is light-absorbing platinum black, such an effect cannot be expected, and it is considered that the above-mentioned result is obtained. (Example 3) A photoresist pattern film was formed by a photolithography method, and a comb-shaped electrode (electrode width 10 μm, electrode interval 10 μm, copper plating film thickness 20 μm, platinum plating) was formed by electroforming using this resist pattern film. A photoelectric conversion element was produced by the same method as that of the element 1 of Example 1 except that the film thickness was 1 μm).

The photoelectric conversion efficiency of the obtained photoelectric conversion element is
When AM1.5 pseudo sunlight (intensity 100 mW) was measured as a light source, the efficiency was very high at 12.7%. Example 4 Using a dry film having a thickness of 40 μm,
A photoresist pattern is formed by the photolithography method, and a comb-shaped electrode (electrode width 20 μm, interelectrode gap 20 μm) is formed by electroforming using this resist pattern film.
m, thickness of copper plating 40 μm, thickness of platinum plating 0.1
A photoelectric conversion element was manufactured by the same method as that of the element of Example 1 described above except that (.mu.m) was formed.

The photoelectric conversion efficiency of the obtained photoelectric conversion element is
When AM1.5 pseudo sunlight (intensity 100 mW) was measured as a light source, the efficiency was very high at 13.4%. (Example 5) As a substrate for forming a comb-shaped electrode, SUS304 having a silica coating on the surface and having a thickness of 0.1 mm.
A photoelectric conversion element was produced in the same manner as in Example 1 except that the substrate was used instead of the glass substrate.

The obtained photoelectric conversion element showed high photoelectric conversion efficiency equivalent to that of Example 1. Example 6 As a substrate for forming a comb-shaped electrode, the above-described Example 1 was used except that an aluminum foil having a surface coated with silica and having a thickness of 50 μm was used instead of the glass substrate.
A photoelectric conversion element was produced by the same method as in.

The obtained photoelectric conversion element showed high photoelectric conversion efficiency equivalent to that of Example 1. (Example 7) The same method as in Example 1 except that a polypropylene film having a thickness of 1 mm and having a silica coating on the surface was used as a light-transmissive substrate instead of the glass plate cover that covers the upper surface of the titanium oxide semiconductor layer. Then, a photoelectric conversion element was produced.

The obtained photoelectric conversion element showed a high photoelectric conversion efficiency equivalent to that of Example 1. (Example 8) Ruthenium 620 as a ruthenium complex
(SOLARONIX) and a device similar to the above-described Example 1 except that a thiocyanate of the ruthenium complex used in Example 1 was converted into a chloride ion, a bromide ion, and a cyanide ion, respectively. 1
And element 2 were produced.

Regarding the obtained elements 1 and 2, A
M1.5 pseudo sunlight (intensity 100mW) as a light source,
The photoelectric conversion efficiency was measured for each. As a result, even when any of the ruthenium complexes is used, the device 1 using the comb-shaped electrode of the present invention has a higher photoelectric conversion efficiency as compared with the laminated photoelectric conversion device 2 using the conventional transparent conductive electrode. Was obtained. (Example 9) Instead of the electrolytic solution, polyvinylidene fluoride-
Polyhexafluoropropylene copolymer (copolymerization ratio vinylidene fluoride: hexafluoropropylene = (86:
14) and an electrolytic solution were used, and the electrolytic solution was injected under heating conditions, followed by cooling to room temperature, and the same procedure as in Example 1 except that the charge transport layer was a gel electrolyte. And the element 2 was produced.

Regarding the elements 1 and 2 obtained as described above, AM1.5 pseudo sunlight (intensity 100 m
The photoelectric conversion efficiency was measured using W) as a light source.
As a result, the element 1 had better photoelectric conversion efficiency than the element 2. Example 10 First, a surface of a SUS304 substrate having a thickness of 0.1 mm was coated with silica having a thickness of about 0.1 μm by a dip coating method using a sol-gel solution.

A 10 × 10 cm region of the SUS33043 substrate on which the silica coating was formed was electroformed using a photoresist pattern film, and the electrode width was 20 μm, the interelectrode distance was 20 μm, the electrode length was 10 cm, and the film thickness was 20 μm. A platinum electrode pattern was formed.

Next, SUS30 having a comb-shaped electrode is formed.
The 4 substrates were immersed in a suspension in which silica particles (average particle size 0.1 μm) were suspended, and the cathode was electrified to deposit a 2 μm thick silica particle layer on the cathode by electrodeposition. This silica particle layer is impregnated with an electrolyte solution in a later step to form a charge transport layer.

After electrodeposition, a titanium dioxide paste containing titanium dioxide fine particles (average particle diameter 20 nm) was applied to the entire surface of the substrate on which the electrode was formed so that the film thickness on the anode was 10 μm, and the temperature was set at 450 ° C. The titanium dioxide layer was formed by firing. After firing, (cis-di (thiocyanato)-
3 × 10 ^{−4 of} N, N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) dihydrate)
It was immersed in an M dry ethanol solution (temperature of about 80 ° C.) for 4 hours. After that, by pulling up under an argon stream,
A ruthenium complex was supported on the titanium dioxide layer to form a semiconductor layer.

After drying with ethanol, a glass plate cover as a light-transmissive substrate was covered on the semiconductor layer, and the periphery was sealed with an epoxy resin leaving an electrolyte solution injection port. From the inlet, (tetrapropylammonium iodide) = 0.5M, (potassium iodide) = 0.02M, [I ₂ ] = 0.03M acetonitrile / ethylene carbonate mixed solvent (volume ratio 10/9
0) A solution was injected, and the above-mentioned silica particle layer was impregnated with this solution to form a charge transport layer.

Finally, the injection port was sealed with an epoxy resin to form the photoelectric conversion element of Example 1 (element 1). The obtained photoelectric conversion element showed high photoelectric conversion efficiency equivalent to that of Example 1. (Example 11) Instead of titanium dioxide particles, CuAlO ₂ particles having an average particle diameter of 20 μm were used, and instead of a ruthenium complex, perylene diimide (P
Devices 1 and 2 were produced in the same manner as in Example 1 except that DI-1) was used, the electrode corresponding to the anode of Example 1 was used as the cathode, and the electrode corresponding to the cathode was used as the anode.

Regarding the elements 1 and 2 obtained as described above, AM1.5 pseudo sunlight (intensity 100 m
The photoelectric conversion efficiency was measured using W) as a light source.
As a result, in comparison with the stacked photoelectric conversion element 2 using the conventional transparent conductive electrode, the element 1 using the comb-shaped electrode of the present invention has the same high photoelectric conversion efficiency as that of the example 1. .

[0081]

[Chemical 1] Example 12 A 10 cm × 10 cm porous aluminum plate having a thickness of 100 μm, a porosity of 90% and an average pore diameter of 50 μm was subjected to platinum plating to form a platinum layer having a thickness of about 50 nm on the surface.

This porous aluminum plate was immersed in a titanium dioxide paste containing titanium dioxide fine particles (average particle size 20 nm) similar to that used in Example 1 and dried,
By firing at 450 ° C, the surface has a thickness of 10 μm
The above titanium dioxide layer was formed. This was dried at 3 × 10 ⁻⁴ M of (cis-di (thiocyanato) -N, N-bis (2,2′-dipyridyl-4,4′-dicarboxylic acid) -ruthenium (II) dihydrate). Ethanol solution (Temperature about 80
C.) for 4 hours. After that, the ruthenium complex was supported on the titanium dioxide layer by pulling it up under an argon stream to form a semiconductor layer.

On the other hand, a platinum thin film was formed on a separately prepared glass substrate by a sputtering method to form a cathode electrode. A paste in which silica particles (average particle diameter 1 μm) similar to those used in Example 1 were suspended was applied on this cathode electrode to form a porous silica particle layer having a thickness of 5 μm. On this silica particle layer, the porous aluminum plate on which the above-mentioned semiconductor layer was formed was placed, and a glass plate for a cover was further placed thereon, and the periphery was sealed with an epoxy resin leaving an electrolyte solution inlet. . From the inlet (tetrapropylammonium iodide) = 0.5M, (potassium iodide) = 0.0
A solution of acetonitrile / ethylene carbonate mixed solvent (volume ratio 10/90) of 2M, [I ₂ ] = 0.03M was injected, and this solution was impregnated into the silica particle layer to form a charge transport layer.

Finally, the injection port was sealed with an epoxy resin to form the photoelectric conversion element 3. Also, for comparison,
A photoelectric conversion element 4 was produced in the same manner as the element 2 of Example 1 except that the thickness of the porous silica particle layer was 5 μm.

Regarding the elements 3 and 4 obtained as described above, AM1.5 pseudo sunlight (intensity 100 m
The photoelectric conversion efficiency was measured using W) as a light source.
As a result, the element was 3: 10.1% and the element was 4: 9.2%, which is an element 3 using the mesh electrode of the present invention as compared with the conventional laminated photoelectric conversion element 4 using a transparent conductive electrode. Obtained a high photoelectric conversion efficiency. (Example 13) CuAlO ₂ fine particles having an average particle diameter of 20 μm were used in place of the titanium dioxide fine particles, and perylene diimide (P) represented by the above chemical formula was used in place of the ruthenium complex.
Using DI-1), elements 3 and 4 were produced in the same manner as in Example 12 except that the electrode corresponding to the anode of Example 12 was used as the cathode and the electrode corresponding to the cathode was used as the anode.

For the obtained elements 3 and 4, AM
The photoelectric conversion efficiency was measured using 1.5 pseudo sunlight (intensity 100 mW) as a light source. As a result, in comparison with the stacked photoelectric conversion element 4 using the conventional transparent conductive electrode,
The device 3 using the comb-shaped electrode of the present invention had the same high photoelectric conversion efficiency as in Example 12.

[0087]

As described above, according to the present invention,
A sufficient incident light intensity to the semiconductor layer is secured without using a transparent electrode that raises the internal resistance of the cell, and the incident light in the semiconductor layer is prevented from increasing without increasing the interelectrode distance between the anode and the cathode. A high-efficiency photoelectric conversion element having a long optical path length, an inexpensive resin substrate that can be used as a light-transmissive substrate, and a constant photoelectric conversion efficiency is provided. INDUSTRIAL APPLICABILITY The photoelectric conversion element of the present invention can avoid all the problems of the conventional laminated photoelectric conversion element, and its industrial value is enormous.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a photoelectric conversion element of the present invention.

FIG. 2 is a schematic diagram showing an example of an electrode pattern in the photoelectric conversion element of the present invention.

FIG. 3 is an enlarged view showing a connection state of lead wire portions in the photoelectric conversion element of the present invention.

FIG. 4 is a cross-sectional view showing another example of the photoelectric conversion element of the present invention.

FIG. 5 is a sectional view schematically showing a conventional photoelectric conversion element.

[Explanation of symbols]

10 ... Photoelectric conversion element 11 ... Substrate 12a ... First polarity electrode 12b ... electrode of the second polarity 13 ... Semiconductor layer 14 ... Charge transport layer 15 ... Light transmissive substrate 16 ... Sealant 18 ... Lead wire part 19 ... Conductive through hole 30 ... Photoelectric conversion element 31 ... Substrate 32 ... First polarity electrode 33 ... Charge transport layer 34 ... Porous sheet-shaped second polarity electrode 35 ... Porous semiconductor layer 36 ... Light transmissive substrate 40 ... Grazel cell 41 ... Light transmissive substrate 42 ... Transparent electrode 43 ... Metal oxide semiconductor layer 44 ... Light-transmissive substrate 45 ... Counter electrode 46 ... Electrolyte layer 48 ... light

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-104463 (JP, A) JP-A-11-260427 (JP, A) JP-A-10-112337 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01L 31/04-31/078 H01M 14/00

Claims (5)

(57) [Claims] 1. A substrate having at least one surface having an insulating property, a pair of electrodes formed on the insulating surface of the substrate, the electrode having a first polarity and an electrode having a second polarity, the first polarity A dye-carrying semiconductor layer formed on the first polarity electrode in contact with the second polarity electrode and an ion conductive material or holes formed between the second polarity electrode and the semiconductor layer. A photoelectric conversion element comprising a charge transport layer containing a conductive substance. 2. The photoelectric conversion element according to claim 1, wherein the first-polarity electrode and the second-polarity electrode are comb-shaped electrodes. 3. The aspect ratio of the first polarity electrode and the second polarity electrode is 0.5 or more.
The photoelectric conversion element described in 1. 4. The light-transmitting resin layer is provided on the semiconductor layer carrying the dye.
The photoelectric conversion element according to item. 5. A substrate, at least one surface of which is insulative, a first polarity electrode formed on the insulative surface of the substrate, and an ion conductive layer formed on the first polarity electrode. A porous semiconductor layer having a charge transport layer containing a conductive substance or a hole conductive substance, and a porous sheet-shaped second polarity electrode embedded on the charge transport layer, the porous sheet The electrode of the second polarity has a continuous pore having openings on the front surface and the back surface, and the porous semiconductor layer carries a dye, and the photoelectric conversion element is characterized in that.