JP2000077691A - Photoelectric cell - Google Patents

Abstract

(57) [Problem] To provide a photoelectric cell having excellent photoelectric conversion efficiency. An electrode layer (1) is provided on a surface, and the electrode layer (1) is provided.
Metal oxide semiconductor layer with spectral sensitizing dye adsorbed on its surface (2)
And an insulating substrate having an electrode layer (3) on the surface, the electrode layers (1) and (3) are arranged so as to face each other, a metal oxide semiconductor layer In the photoelectric cell in which the electrolyte is sealed between (2) and the electrode layer (3), the conductive layer has a conductive protrusion (4) projecting from the surface of the electrode layer (1),
And the metal oxide semiconductor layer has a conductive protrusion and an electrode layer.
(1) A photovoltaic cell formed so as to cover (1), wherein at least one of the insulating substrate and the electrode layer has transparency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal oxide semiconductor layer having a high adsorption and carrying amount of a spectral sensitizing dye, a high binding force between the metal oxide semiconductor layer and the spectral sensitizing dye, and a high photoelectric conversion efficiency. An improved photoelectric cell.

[0002]

BACKGROUND OF THE INVENTION A photoelectric conversion material is a material that can continuously take out light energy as electric energy, and is a material that converts light energy into electric energy by utilizing an electrochemical reaction between electrodes. When such a photoelectric conversion material is irradiated with light, electrons are generated on one electrode side, move to the counter electrode, and the electrons moved to the counter electrode move as ions in the electrolyte and return to the one electrode. Since this energy conversion is continuous, it is used for, for example, solar cells.

In a general solar cell, first, a film of a semiconductor for a photoelectric conversion material is formed on a support such as a glass plate coated with a transparent conductive film to form an electrode, and then another transparent electrode is formed as a counter electrode. A support such as a glass plate coated with a conductive film is provided, and an electrolyte is sealed between these electrodes.

When the spectral sensitizing dye adsorbed on the semiconductor for a photoelectric conversion material is irradiated with sunlight, the spectral sensitizing dye absorbs and excites light in the visible region. The electrons generated by this excitation move to the semiconductor, then to the transparent conductive glass electrode, move to the counter electrode through the conductor connecting the two electrodes, and the electrons transferred to the counter electrode are oxidized in the electrolyte. Reduce the reduction system. On the other hand, the spectral sensitizing dye that has transferred electrons to the semiconductor is in an oxidized state, which is reduced by a redox system in the electrolyte and returns to the original state. In this way, electrons flow continuously, and the photoelectric conversion material functions as a solar cell.

As this photoelectric conversion material, a material in which a spectral sensitizing dye having absorption in a visible light region is adsorbed on a semiconductor surface is used. For example, Japanese Patent Application Laid-Open No. Hei.
Japanese Patent Laid-Open Publication No. HEI 9-176566 describes a solar cell having a spectral sensitizing dye layer made of a transition metal complex such as a ruthenium complex on the surface of a metal oxide semiconductor. In addition, Tokuhyo Hei 5-5040
No. 23 describes a solar cell having a spectral sensitizing dye layer made of a transition metal complex such as a ruthenium complex on the surface of a titanium oxide semiconductor layer doped with metal ions.

[0006] In the above-mentioned solar cell, it is important to improve the light conversion efficiency that electrons are rapidly transferred from the spectral sensitizing dye layer, which has absorbed and excited light, to the titania film. If the reaction is not performed, recombination of the ruthenium complex and the electrons occurs again, and there is a problem that the light conversion efficiency is reduced.

For this reason, studies have been made to increase the amount of adsorption between the surface of the titania film and the spectral sensitizing dye or to improve the mobility of electrons in the titania film. For example, when forming a titanium oxide semiconductor film, a process of applying titania sol on an electrode substrate, drying, and then firing is repeated to form a porous thick film, and the surface of the semiconductor film is made porous. It has been proposed to increase the amount of the Ru complex supported on. It has also been proposed that the titania fine particles be fired at a temperature of 400 ° C. or higher to improve the conductivity. Furthermore, Tokuhyo Hei 6-51111
In order to increase the effective surface, No. 3 proposes immersing in an aqueous solution of titanium chloride or electrochemically depositing it on a titania film using a hydrolysis solution of titanium chloride.

However, in these methods, the titanium oxide semiconductor film is fired in order to improve the electron mobility. Therefore, the porosity (effective surface) is reduced by sintering of the particles, and the spectral sensitizing dye is reduced. There is a problem such as a decrease in the amount of adsorbed, and the photoelectric conversion efficiency is not always sufficient, the use is limited, and further improvement has been desired.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photoelectric cell having a high adsorption amount of a spectral sensitizing dye into a semiconductor layer and having improved photoelectric conversion efficiency.

[0010]

The photoelectric cell according to the present invention has an electrode layer (1) on the surface and a metal oxide semiconductor layer (2) having a spectral sensitizing dye adsorbed on the surface of the electrode layer (1). An insulating substrate formed and an insulating substrate having an electrode layer (3) on the surface are arranged so that the electrode layers (1) and (3) face each other,
In a photoelectric cell in which an electrolyte is sealed between the metal oxide semiconductor layer (2) and the electrode layer (3), the conductive layer has a conductive protrusion (4) projecting from the surface of the electrode layer (1), And the metal oxide semiconductor layer is formed so as to cover the conductive projecting portion (4) and the electrode layer (1), and at least one of the insulating substrate and the electrode layer has transparency. And

[0011] The metal oxide semiconductor layer may include a conductive protruding portion.
Preferably, it is formed so as to conform to the shape of (4). Further, the metal oxide semiconductor layer is formed of at least one or two or more metal oxides selected from titanium oxide, lanthanum oxide, zirconium oxide, niobium oxide, tungsten oxide, strontium oxide, zinc oxide, tin oxide, and indium oxide. It is preferable to include spherical particles of

The average particle diameter of the spherical particles is 5 to 600.
It is preferably in the range of nm. Such spherical particles are preferably made of anatase type titanium oxide.
Moreover, the spherical particles may be spherical particles having a core-shell structure in which a shell portion made of a metal oxide is formed on the surface of metal oxide core particles having an average particle diameter of 0.1 to 500 nm. In such a spherical particle having a core-shell structure, it is particularly preferable that the shell part is anatase type titanium oxide.

It is preferable that the anatase type titanium oxide is obtained by heating and aging peroxotitanic acid. In addition, the metal oxide semiconductor layer may include a titanium oxide binder together with the metal oxide spherical particles.

Further, the metal oxide semiconductor layer is
It is preferably annealed after implanting ions of at least one gas selected from O ₂ , N ₂ , H ₂ and an inert gas of Group 0 of the periodic table.

In the photovoltaic cell according to the present invention, the pore volume of the formed metal oxide semiconductor layer is 0.05 to 0.8 ml.
/ G, and the average pore diameter is preferably in the range of 2 to 250 nm.

[0016]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be specifically described. [Photoelectric cell] The photoelectric cell of the present invention has an electrode layer on the surface.
An insulating substrate having (1), and a metal oxide semiconductor layer (2) having a spectral sensitizing dye adsorbed on the surface thereof, and an electrode layer (3) on the surface. An insulating substrate and the electrode layers (1) and (3) are arranged so as to face each other, and an electrolyte is sealed between the metal oxide semiconductor layer (2) and the electrode layer (3). In the photoelectric cell, the electrode layer (1) has a conductive protrusion (4) projecting from the surface, and a metal oxide semiconductor layer is formed so as to cover the conductive protrusion (4), At least one of the insulating substrate and the electrode layer has transparency.

FIG. 1 shows an example of such a photoelectric cell. FIG. 1 is a schematic cross-sectional view showing one embodiment of the photoelectric cell according to the present invention. And a transparent electrode layer 3 on the surface of a transparent insulating substrate 7 having a metal oxide semiconductor layer 2 having a spectral sensitizing dye adsorbed thereon and formed so as to cover the conductive protrusions 4. The transparent insulating substrate is disposed so that the electrode layers 1 and 3 face each other, and an electrolyte 5 is sealed between the metal oxide semiconductor layer 2 and the transparent electrode layer 3.

The insulating substrate 6 is not particularly limited as long as it has insulating properties, and can be used. Further, as the transparent insulating substrate 7, a transparent and insulating substrate such as a glass substrate or a polymer substrate such as PET can be used.

The material for forming the electrode layer 1 formed on the surface of the insulating substrate 6 and the conductive projecting portion 4 protruding from the surface of the electrode layer 1 is tin oxide, tin oxide doped with Sb, F or P. , Indium oxide, Sn and / or F
Doped indium oxide, antimony oxide,
A conventionally known conductive material such as a noble metal such as platinum can be used. The electrode layer 1 and the conductive protrusions 4 may be formed from the same conductive material or different conductive materials.

The shape of the conductive protruding portion is not limited to the rectangular parallelepiped shape as shown in FIG.
It may be mesh-like. Electrode layer 1 and conductive protrusion 4
Is electrically conducting. The method for forming the electrode layer 1 and the conductive protrusions 4 is not particularly limited. For example, the electrode film is formed on an insulating substrate by a thermal decomposition method, a CVD method, or the like.
After forming by a method, a vapor deposition method, or the like, a method of applying a resist on the film surface, patterning the conductive projecting portion 4, and etching the resist is used.

After the electrode layer 1 is formed by a CVD method, a vapor deposition method, or the like, a coating solution containing conductive particles made of the above-described conductive material is applied to form a conductive particle layer. 4 may be formed (FIG. 2). After applying a coating solution containing conductive particles made of the above-mentioned conductive material to form a conductive particle layer so as to be a fine packing, a layer surface is coated with a resist, and the conductive protrusions 4 are patterned. Then, the conductive protrusions 4 can be formed by etching the resist (FIG. 3).

It is preferable that the conductive protrusions 4 are located at a distance of at least twice the average thickness of the metal oxide semiconductor layer 2. In addition, the height of the conductive projecting portion 4 is
Is preferably in the range of 20% to 98% of the thickness of the metal oxide semiconductor layer, including In such a range, the electrons in the metal oxide semiconductor layer move quickly to the electrode layer 1 without recombining with the spectral sensitizing dye, so that the photoelectric conversion efficiency of the photoelectric cell increases. If it is less than 20%, the effect of improving the electron transfer speed to the electrode layer 1 is insufficient, and if it exceeds 98%, conduction with the electrolyte may occur.

The transparent electrode layer 3 formed on the surface of the transparent insulating substrate 7 includes tin oxide, tin oxide doped with Sb, F or P, indium oxide, Sn and / or tin.
Alternatively, a transparent electrode such as indium oxide or antimony oxide doped with F can be used. As a method for forming the transparent electrode layer 3, a known method such as a thermal decomposition method, a CVD method, and an evaporation method can be adopted.

The higher the visible light transmittance of the insulating substrate 6 and the electrode layer 3 is, the more preferable it is, specifically, 50% or more.
Particularly preferably, it is 90% or more. Visible light transmittance is 50
% Is not preferable because the photoelectric conversion efficiency is low.

In the photovoltaic cell according to the present invention, one of the pair of the insulating substrate and the electrode layer may be at least transparent. For this reason, the present invention is not limited to the photoelectric cell shown in FIG. 1. For example, the insulating substrate 6, the electrode layer 1, and the conductive protrusions 4 may be transparent. All of the layers 1 and 3 and the conductive protrusion 4 may be transparent.

The electrode layers 1 and 3 and the conductive protrusion 4
Is usually 50Ω / cm ^TwoTo be
preferable. The resistance value of the electrode layer is 50Ω / cm^TwoBeyond high
In such a case, the photoelectric conversion efficiency may be similarly reduced.

In the photovoltaic cell according to the present invention, the metal oxide semiconductor layer 2 is formed so as to cover the electrode layer 1 and the conductive protrusion 4. The metal oxide semiconductor layer 2 may embed the conductive protrusion 4 or may be formed so as to follow the shape formed by the electrode layer 1 and the conductive protrusion 4.

In particular, as shown in FIG. 4, it is desirable that the metal oxide semiconductor layer is formed so as to follow the shape composed of the electrode layer 1 and the conductive protrusion 4. When formed in this manner, the electrolyte penetrates into the metal oxide semiconductor layer, the contact area between the metal oxide semiconductor layer and the electrolyte increases, the amount of received light increases, and the amount of spectral sensitizing dye adsorption increases. The photoelectric conversion efficiency is improved by the increase.

The thickness of the metal oxide semiconductor layer including the conductive protrusion 4 is preferably in the range of 0.1 μm to 500 μm, and is formed on the conductive protrusion or on the surface of the electrode layer. The thickness of the metal oxide semiconductor layer is 0.1 to 50.
It is preferably in the range of μm.

Note that, as shown in FIG. 5, the average thickness of the metal oxide semiconductor layer refers to the average value of the thickness of the metal oxide semiconductor layer including the conductive protrusion. The thickness of the layer is the thickness of the oxide semiconductor layer provided on the surfaces of the electrode layer 1 and the conductive protrusion 4. Further, the depth at which the electrolyte penetrates into the metal oxide semiconductor layer (the depth of the electrolyte penetration portion) is 20% to 90% of the thickness of the metal oxide semiconductor layer.
Is preferably within the range. If the depth of the electrolyte penetration part is less than 20%, the effect of increasing the amount of received light is not sufficient, and
%, The strength of the metal oxide semiconductor layer may be insufficient.

As such a metal oxide semiconductor layer,
A metal oxide semiconductor layer composed of spherical particles of a metal oxide such as titanium oxide, lanthanum oxide, zirconium oxide, niobium oxide, tungsten oxide, strontium oxide, zinc oxide, tin oxide, and indium oxide is preferable.

Such metal oxide spherical particles preferably have an average particle diameter in the range of 5 to 600 nm. In the case of spherical particles, when the particles are densely packed, a uniform pore structure based on the particle diameter is formed. Furthermore, if the particles are spherical, a uniform surface state can be obtained. Therefore, the electron transfer from the spectral sensitizing dye to the metal oxide semiconductor layer is performed efficiently, and as a result, the electron mobility is improved. The particle size of the metal oxide particles can be measured with a laser Doppler particle size analyzer (Microtrack manufactured by Nikkiso Co., Ltd.). The average particle diameter of the metal oxide particles is 5 nm
When the number is less than 1, cracks are easily generated in the formed metal oxide semiconductor layer, and it is difficult to form the metal oxide semiconductor layer in a small number of times and without cracks. The pore diameter and pore volume of the oxide semiconductor layer may decrease, and the amount of the spectral sensitizing dye adsorbed may decrease. The average particle diameter of the metal oxide particles is 60
When it is larger than 0 nm, the strength of the metal oxide semiconductor layer may be insufficient.

As such metal oxide spherical particles,
Spherical particles composed of anatase type titanium oxide are preferred.
The anatase type titanium oxide particles can be obtained by adding alkali, preferably ammonia and / or amine, to peroxotitanic acid to make it alkaline, followed by heating and aging in a temperature range of 80 to 350 ° C.
Further, after adding peroxotitanic acid with the obtained anatase type titanium colloid particles as seed particles, it is also possible to repeat the above-mentioned process. This is preferable since colloidal particles of anatase type titanium having a high particle size can be obtained. In addition,
"Peroxotitanic acid" is prepared by adding hydrogen peroxide to a titanium compound such as titanium hydride, titanium alkoxide, titanic acid, or a hydrous titanic acid gel or sol, and heating as necessary.

The sol or gel of hydrated titanium oxide is obtained by adding an acid or alkali to an aqueous solution of a titanium compound, hydrolyzing the resultant, and washing, heating and aging as necessary. The titanium compound used is not particularly limited, but titanium halides, titanium salts such as titanyl sulfate,
A titanium alkoxide such as tetraalkoxytitanium or a titanium compound such as titanium hydride can be used.

In the present invention, the metal oxide spherical particles have a core-shell structure having cells made of the metal oxide on the surface of metal oxide core particles having an average particle diameter in the range of 0.1 to 500 nm. Spherical particles are also preferably used. In the case of spherical particles having a core shell structure,
The core particles are not particularly limited as long as they are spherical particles, but silica particles or the like from which true spherical particles are easily obtained are preferably used. In the metal oxide particles having such a core-shell structure, the shell portion is made of the above-described metal oxide, and the shell portion is preferably made of titanium oxide, particularly preferably anatase type titanium oxide.

The spherical particles having such a core-shell structure can be obtained by heating the dispersion of the core particles having the above-mentioned particle diameter, if necessary, and gradually adding peroxotitanic acid. it can.

When the particles are anatase type titanium oxide or the shell part is anatase type titanium oxide, the adsorption amount of the spectral sensitizing dye is higher than other metal oxide particles, It has excellent characteristics such as high electron mobility from the metal oxide semiconductor to the metal oxide semiconductor and electron mobility in the metal oxide semiconductor layer, and furthermore, stability, safety and easy film formation.

The preferable range of the crystallite diameter of such anatase type titanium oxide is 5 to 50 nm, and the more preferable range is 7 to 30 nm. The crystallite diameter of anatase-type titanium oxide is determined by measuring the half-width of the (1.0.1) plane peak by X-ray analysis and calculating by the Debye-Scherrer equation. When the crystallite diameter of the anatase type titanium oxide particles is less than 5 nm, the electron mobility in the particles decreases, and when it exceeds 50 nm, the adsorption amount of the spectral sensitizing dye decreases and the photoelectric conversion efficiency decreases. Sometimes.

The metal oxide semiconductor layer may contain a binder component together with the metal oxide spherical particles.
Examples of such a binder component include amorphous titanium oxide obtained by a sol-gel method, peroxotitanic acid obtained by dissolving particles obtained by a sol-gel method with hydrogen peroxide, and further hydrolyzing / condensing this peroxotitanic acid. Examples include amorphous titanium oxide obtained by polymerization. Among these, amorphous titanium oxide obtained by hydrolyzing and polycondensing peroxotitanic acid is particularly preferable. When spherical particles having a core-shell structure in which an anatase-type titanium oxide particle or a shell portion is formed from anatase-type titanium oxide are used as the spherical particles, such a hydrolyzed / condensed polymer of peroxotitanic acid is Forming a dense and uniform adsorption layer on the surface of the anatase type titanium oxide particles. Thus, the obtained metal oxide semiconductor layer can increase the adhesion to the electrode. Furthermore, when such peroxotitanic acid is used as a binder component, the contact between the anatase-type titanium oxide particles changes from point contact to surface contact, and the electron mobility can be improved.

The ratio of amorphous titanium oxide to metal oxide spherical particles in the metal oxide semiconductor layer is 0.05 as a weight ratio in terms of oxide (amorphous titanium oxide / metal oxide spherical particles).
0.7, preferably 0.1０．１0.5. If the weight ratio is less than 0.05, the strength of the metal oxide semiconductor layer may be insufficient, or the adhesion between the electrode and the metal oxide semiconductor layer may be insufficient.
When the weight ratio is higher than 0.7, since the pore diameter of the pores to be generated is too small, the exchange of electrons between the electrolyte and the spectral sensitizing dye tends to be suppressed. May not improve.

The metal oxide semiconductor layer has a pore volume of 0.0
It is preferable that the concentration is 5 to 0.8 ml / g and the average pore diameter is in the range of 2 to 250 nm. Pore volume is 0.05ml / g
If it is smaller, the amount of the spectral sensitizing dye adsorbed will be low, and if it is more than 0.8 ml / g, the electron mobility in the layer will be reduced and the photoelectric conversion efficiency may be reduced. Further, when the average pore diameter is less than 2 nm, the adsorption amount of the spectral sensitizing dye decreases, and when it exceeds 250 nm, the electron mobility decreases and the photoelectric conversion efficiency may decrease.

Such a metal oxide semiconductor layer is coated with a coating liquid for forming a metal oxide semiconductor layer for a photoelectric cell containing metal oxide spherical particles, a dispersion medium, and, if necessary, a binder, and then dried. Can be formed.

The dispersion medium is not particularly limited as long as it can disperse the metal oxide particles and the binder component and can be removed when dried. Alcohols are particularly preferable.

The coating solution may contain a forming aid as required. Examples of the forming aid include polyethylene glycol, polyvinylpyrrolidone, hydroxypropylcellulose, polyacrylic acid, and polyvinyl alcohol.

When such a forming aid is contained in the coating solution, the viscosity of the coating solution increases, whereby a uniformly dried layer is obtained, and the anatase type titanium oxide particles are densely packed. Thus, a metal oxide semiconductor layer having high adhesion to an electrode can be obtained.

The coating solution is preferably applied so that the finally formed metal oxide semiconductor layer has a thickness of 0.1 to 50 μm. As a method of applying the coating liquid,
It can be applied by a conventionally known method such as a dipping method, a spinner method, a spray method, a roll coater method, flexographic printing, and a transfer method.

The drying temperature may be any temperature at which the dispersion medium can be removed. After drying, if necessary, ultraviolet rays may be further irradiated to cure the peroxotitanic acid contained as a binder component. The irradiation amount of the ultraviolet ray varies depending on the content of the peroxotitanic acid and the like, but the irradiation may be performed in an amount necessary to decompose and cure the peroxotitanic acid. If a molding aid is included, after curing,
The formation aid may be decomposed by heat treatment.

In the formed metal oxide semiconductor layer,
It is preferable to implant ions of O ₂ , N ₂ , H ₂ and at least one gas selected from inert gases of Group 0 of the periodic table, such as neon, argon, and krypton, followed by annealing. As a method of ion implantation, a known method such as a method of implanting B and P into a silicon wafer at a constant amount and a constant depth when manufacturing an IC or LSI can be adopted.

Annealing is performed by heating at a temperature of 200 ° C. to 500 ° C., preferably 250 ° C. to 400 ° C., for 10 minutes to 20 hours. As the ions to be irradiated, ions having no reactivity with the metal oxide described above are preferable. By the ion implantation of these gases, these ions do not remain in the metal oxide semiconductor layer, and many defects are generated on the surface of the metal oxide particles. Bonding is promoted, thereby increasing the bonding strength with the spectral sensitizing dye and increasing the amount of adsorption.In the case of titanium oxide particles, the electron mobility is improved by improving the crystallinity and promoting the bonding of the particles. It is preferable because the photoelectric conversion efficiency is improved.

In the photovoltaic cell according to the present invention, the metal oxide semiconductor layer adsorbs the spectral sensitizing dye. The spectral sensitizing dye is not particularly limited as long as it absorbs and excites light in a visible light region and / or an infrared light region. For example, an organic dye or a metal complex can be used.

As the organic dye, conventionally known organic dyes having a functional group such as a carboxyl group, a hydroxyalkyl group, a hydroxyl group, a sulfone group, and a carboxyalkyl group in the molecule can be used. Specific examples thereof include metal-free phthalocyanine, cyanine-based dyes, metalocyanine-based dyes, triphenylmethane-based dyes, and xanthene-based dyes such as uranine, eosin, rose bengal, rhodamine B, and dibromofluorescein. These organic dyes have a characteristic that the adsorption speed to a metal oxide semiconductor is high.

As the metal complex, JP-A No. 1-22
Metal phthalocyanines such as copper phthalocyanine and titanyl phthalocyanine described in JP-A-3380 and JP-A-5-504033, chlorophyll, hemin, ruthenium-tris (2,2′-bispyridyl-4,4′-dicarboxylate) ), Ruthenium-cis-diaqua-bis (2,2'-bipyridyl-4,4'-dicarboxylate)
-Diaqua-bipyridyl complexes, porphyrins such as zinc-tetra (4-carboxyphenyl) porphine, and complexes of ruthenium, osmium, iron, zinc and the like such as iron-hexacyanide complex. These metal complexes are excellent in the effect of spectral sensitization and durability.

The above-mentioned organic dyes and metal complexes may be used alone, or two or more kinds may be used in combination, and the organic dyes and metal complexes may be used in combination. The method of adsorbing such a spectral sensitizing dye is not particularly limited, and a general method of absorbing a solution of the spectral sensitizing dye in a solvent into a metal oxide semiconductor layer and then drying the solution can be employed. Further, the above steps may be repeated as necessary. Alternatively, the spectral sensitizing dye solution may be brought into contact with and adsorbed to the substrate while being heated under reflux.

Any solvent may be used as long as it can dissolve the spectral sensitizing dye, and specifically, water, alcohols, toluene, dimethylformamide, chloroform, ethylcellosolve, N-methylpyrrolidone, tetrahydrofuran and the like are used. be able to.

The amount of the spectral sensitizing dye adsorbed on the metal oxide semiconductor layer is preferably at least 100 μg per 1 cm ² of the specific surface area of the metal oxide semiconductor layer. When the amount of the spectral sensitizing dye is less than 100 μg, the photoelectric conversion efficiency may be insufficient.

The photoelectric cell according to the present invention is formed by arranging the metal oxide semiconductor layer 2 and the transparent electrode layer 3 so as to face each other, sealing the side surfaces with a resin or the like, and sealing the electrolyte between the electrodes. . As the electrolyte 5, a mixture with at least one compound forming an oxidation-reduction system together with an electrochemically active salt is used.

Examples of the electrochemically active salt include quaternary ammonium salts such as tetrapropylammonium iodide. Examples of the compound forming the redox system include quinone, hydroquinone, iodine, potassium iodide, bromine, potassium bromide and the like.

In the present invention, an electrolyte can be prepared by using a solvent for the electrolyte 5 as necessary. The solvent used at this time desirably has a low solubility of the spectral sensitizing dye to such an extent that the spectral sensitizing dye adsorbed on the metal oxide semiconductor layer does not desorb and dissolve. As the solvent, specifically, water, alcohols, oligoethers, carbonates such as propion carbonate, phosphates, dimethylformamide, dimethylsulfoxide, N-methylpyrrolidone, N-vinylpyrrolidone, a sulfur compound of sulfolane 66, carbonic acid Examples include ethylene and acetonitrile.

In such a photoelectric cell of the present invention, since a specific conductive protrusion is provided on the surface of the electrode, the generated electrons can quickly move to the electrode. Also, electrons do not recombine with the spectral sensitizing dye. Further, the photoelectric cell according to the present invention has a high adsorption amount of the spectral sensitizing dye, and the generated electrons move smoothly. Therefore, the photoelectric cell according to the present invention has excellent photoelectric conversion efficiency.

According to the present invention, the photoelectric conversion efficiency is high,
Photoelectric cells useful for various photoelectric conversion applications such as solar cells can be obtained.

[0060]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0061]

Example 1 Preparation of coating solution 5 g of titanium hydride was suspended in 1 liter of pure water, 400 g of a hydrogen peroxide solution having a concentration of 5% by weight was added over 30 minutes, and then heated to 80 ° C. for dissolution. Then, a solution of peroxotitanic acid was prepared. 90% by volume was collected from the total amount of this solution, adjusted to pH 9 by adding concentrated aqueous ammonia, placed in an autoclave, and subjected to hydrothermal treatment at 250 ° C. for 5 hours under saturated vapor pressure to obtain titania colloid particles (A). Was prepared. The obtained titania colloid particles were anatase-type titanium oxide having high crystallinity by X-ray diffraction. Table 1 shows the average particle size of the anatase type titanium oxide particles.

Next, the titania colloid particles (A) obtained above were concentrated to a concentration of 10% by weight, and the peroxotitanic acid solution was mixed.
Hydroxypropylcellulose was added as a forming aid so as to be 30% by weight of TiO ₂ in terms of TiO ₂ to prepare a coating solution for forming a metal oxide semiconductor layer.

Formation of Electrodes The photoelectric cell shown in FIG. 1 was formed. On one side of the transparent glass substrate 5, a magnet sputtering apparatus (Shimadzu Corporation)
RF Power: 500 W, Ar gas (10 sccc) using fluorine-doped tin oxide as a target using HSR-521A
m), 0.04 torr, 200 min, substrate temperature 250 ° C., a 5 μm thick fluorine-doped tin oxide film was formed. Next, a resist (Tokyo Ohka Co., Ltd .: OFPR-800) is formed on this film.
After coating, patterning of Line & Space having a pitch of 2 μm was performed. Next, using a reactive ion etching RIE apparatus (DEM451T, manufactured by Anelva), RF Power: 500
Etching is performed under the conditions of W, BCl ₃ (40 sccm) and Ar (10 sccm) gas of 10 Pa, and then the resist is removed by ashing, and the electrode layer 1 having a thickness of 0.5 μm and the height of 4.5 μm.
m conductive protruding portions 4 were formed.

On one surface of another transparent glass substrate 6, a magnet sputtering device (HSR-52, manufactured by Shimadzu Corporation) is used.
1A), using fluorine-doped tin oxide as a target, RF Power: 500 W, Ar gas (10 sccm), 0.04 torr, 20 m
Under the conditions of “in”, a 0.5 μm-thick fluorine-doped tin oxide layer was formed, and platinum was supported on the layer to form an electrode layer 3.

Next, the prepared coating solution for forming a metal oxide semiconductor layer is applied onto the electrode layer 1 made of fluorine-doped tin oxide and the conductive protrusions 4, and is naturally dried.
Subsequently, the layer was cured by irradiating ultraviolet rays of 6000 mJ / cm ² using a low-pressure mercury lamp to decompose peroxoacid. Further, the substrate was heated at 300 ° C. for 30 minutes to decompose and anneal hydroxypropyl cellulose, thereby forming a titanium oxide semiconductor layer (A) having a flat metal oxide semiconductor layer surface.

Table 1 shows the thickness of the obtained titanium oxide semiconductor layer (A), the pore volume and the average pore diameter determined by the nitrogen adsorption method. Adsorption of spectral sensitizing dyes Next, cis as spectral sensitizing dyes - (SCN ^-) - bis (2,2'-bipyridyl-4,4'-dicarboxylate) ruthenium complex represented by the ruthenium (II) An ethanol solution having a concentration of 3 × 10 ⁻⁴ mol / liter was prepared. This spectral sensitizing dye solution was applied onto the titanium oxide semiconductor layer (A) using an rpm 100 spinner and dried. This coating and drying process was performed five times. The adsorption amount of the spectral sensitizing dye on the obtained titanium oxide semiconductor layer (A) is shown in the table as the adsorption amount per 1 cm ² of the specific surface area of the titanium oxide semiconductor layer (A).

First, tetrapropylammonium iodide and iodine were added to a solvent in which acetonitrile and ethylene carbonate were mixed at a volume ratio of 1: 4 as a solvent, and the respective concentrations were 0.46 mol / l and 0.06 mol / l. The electrolyte solution was prepared by dissolving so as to be mol / liter.

The electrode layer 1 prepared above and the conductive protrusions 4
The transparent glass substrate 5 with the electrode layer 2 formed thereon is used as one electrode, and the transparent glass substrate 6 with the electrode layer 2 formed thereon is disposed as the other electrode so as to face each other. Was sealed, and the electrodes were connected to each other with a lead wire to produce a light-emitting electric cell (A).

The photoelectric cell (A) is irradiated with light having an intensity of 100 W / m ^{2 by} a solar simulator, and V _oc (voltage in an open circuit state) and J _oc (density of a current flowing when the circuit is short-circuited). ), FF (fill factor) and η (conversion efficiency) were measured, and the results are shown in Table 1.

[0070]

Example 2 A coating solution for forming a metal oxide semiconductor layer was prepared by diluting the concentration of the coating solution for forming a metal oxide semiconductor layer prepared in Example 1 with water so that the concentration became ３. (concentration 3 titania colloidal particles _(a). 3% by weight, hydroxypropyl cellulose in terms of titanium in the liquid to TiO _2, are contained in a concentration of 10 wt% of TiO ₂ by weight).

Using this coating liquid, the coating liquid for forming a metal oxide semiconductor layer prepared as described above was coated on the electrode layer 1 made of fluorine-doped tin oxide and the conductive protrusion 4 as in Example 1. After that, a rapid drying operation was performed six times, and a titanium oxide semiconductor layer was formed so as to have an electrolyte portion penetrating into the same metal oxide semiconductor layer layer as in Example 1.

Then, using a low-pressure mercury lamp, 6000
The peroxoacid was decomposed by irradiating ultraviolet rays of mJ / cm ² , and the titanium oxide semiconductor layer was cured. Further, at 300 ° C., 3
By heating for 0 minutes to decompose and anneal the hydroxypropylcellulose, a titanium oxide semiconductor layer (B) having a flat metal oxide semiconductor layer surface was formed.

Table 1 shows the thickness of the obtained titanium oxide semiconductor layer (B), the pore volume and the average pore diameter determined by the nitrogen adsorption method. Adsorption of spectral sensitizing dye In the same manner as in Example 1 , adsorption of the spectral sensitizing dye was performed on the titanium oxide layer.

Table 1 shows the adsorption amount of the spectral sensitizing dye. Preparation of photoelectric cell A photoelectric cell (B) was prepared in the same manner as in Example 1,
V _oc , J _oc , FF and η were measured and the results are shown in Table 1.

[0075]

[Comparative Example 1] RF Pow was applied on one side of a transparent glass substrate 5 using a magnet sputtering apparatus (HSR-521A, manufactured by Shimadzu Corporation) with fluorine-doped tin oxide as a target.
er: 500 W, Ar gas (10 sccm) 0.04 torr, 20 min, the electrode layer 1 of 0.5 μm thick fluorine-doped tin oxide was formed.

On one surface of another transparent glass substrate 6, using a magnet sputtering apparatus (HSR-521A, manufactured by Shimadzu Corporation), using a fluorine-doped tin oxide as a target, RF
Power: 500W, Ar gas (10sccm) 0.04torr,
Under a condition of 20 min, a 0.5 μm-thick fluorine-doped tin oxide layer was formed, and platinum was supported on the layer to form an electrode layer 3.

Using the transparent glass substrate on which the electrode layer 1 was formed, a titanium oxide semiconductor layer (C) was formed in the same manner as in Example 1.
Was formed. Table 1 shows the thickness of the obtained titanium oxide semiconductor layer (C), and the pore volume and average pore diameter determined by a nitrogen adsorption method.

Adsorption of spectral sensitizing dye In the same manner as in Example 1 , adsorption of the spectral sensitizing dye was performed on the titanium oxide layer (C). Table 1 shows the adsorption amount of the spectral sensitizing dye.

Preparation of Photoelectric Cell A photoelectric cell (C) was prepared in the same manner as in Example 1, and V
_oc , _Joc , FF and η were measured, and the results are shown in Table 1.

[0080]

Example 3 Preparation of Particles Having a Core-Shell Structure 200 g of ethanol, 25 g of pure water and a concentration of 29% by weight
A mixed solution of 7.6 g of tetraethoxysilane and 100 g of ethanol was added to a mixed solution of 60 g of aqueous ammonia at a time to prepare a spherical silica particle dispersion having an average particle size of 0.2 μm. The obtained dispersion was then concentrated by a rotary evaporator to a silica concentration of 10% by weight to obtain a silica particle dispersion (core particles).

[0081] _5. Titanium hydride of 5g was suspended in pure water 1 liter, 3 of hydrogen peroxide solution 400g of 5 wt%
It was added over 0 minutes and then heated to 80 ° C. for dissolution to prepare a solution of peroxotitanic acid.

The previously prepared dispersion of silica particles was heated to 90 ° C., and a solution of peroxotitanic acid was added thereto for 100 hours to obtain metal oxide particles (D) having a silica core and a titanium shell shell. Was prepared. In the obtained metal oxide particles (D), the titanium oxide in the shell portion was an anatase type titanium oxide by X-ray diffraction. Table 1 shows the average particle size of the metal oxide particles (D).

Formation of Photoelectric Cell On one side of the transparent glass substrate 5, using a magnet sputter device (HSR-521A, manufactured by Shimadzu Corporation), targeting fluorine-doped tin oxide, RF Power: 500 W, A
r gas (10 sccm) Under conditions of 0.04 torr and 20 min, electrode layer 1 of fluorine-doped tin oxide having a thickness of 0.5 μm
Was formed.

On one surface of another transparent glass substrate, a magnet sputtering apparatus (HSR-521A, manufactured by Shimadzu Corporation) was used to target the RF P
ower: 500 W, Ar gas (10 sccm) 0.04 torr, 2
Under a condition of 0 min, a 0.5 μm-thick fluorine-doped tin oxide layer was formed, and platinum was carried on the layer to form an electrode layer 3.

A negative photoresist (OMR-83, manufactured by Tokyo Ohka Co., Ltd.) was spin-coated at 500 rpm on the electrode layer 1 to form a 6 μm-thick resist film. Then, after exposure and development with an aligner, a 6 μm pitch Line & Space
Was patterned.

Next, the transparent glass substrate on which the patterned electrode layer 1 was formed was immersed in a dispersion of metal oxide particles (D), and a positive voltage was applied to the transparent glass substrate using a platinum electrode as a counter electrode. Metal oxide particles (D) were laminated between the resists. Thereafter, the weight ratio of the separately prepared peroxotitanic acid as an oxide to the metal oxide particles (D) was 0.1%.
The composition was spin-coated on the metal oxide particle (D) layer so that the particle size became 15, air-dried, and subsequently using a low-pressure mercury lamp.
The metal oxide semiconductor layer was cured by irradiating ultraviolet rays of 6000 mJ / cm ² to decompose the peroxoacid. After curing, O ₂ -As
The resist was removed by hing. Next, a dispersion liquid of indium colloid particles (manufactured by Catalyst Chemicals Ltd .: ARS-22A, particle diameter 0.07
(μm, concentration 2.5% by weight) was spin-coated to remove the resist, and indium colloid particles were filled up to the same height as the metal oxide particles (D) layer to form conductive protrusions 4.

Next, the concentration of 10 obtained in the same manner as above.
% Of the metal oxide particles (D) is mixed with a peroxotitanic acid solution so that the weight ratio as an oxide to the metal oxide particles (D) is 0.15. Hydroxypropylcellulose was added as a forming aid so as to be 30% by weight based on the weight of the metal oxide to prepare a coating solution for forming a metal oxide semiconductor layer, and this was coated with the metal oxide particle (D) layer and It is applied on the conductive protrusions 4 made of indium colloid particles, air-dried again, and subsequently irradiated with 6000 mJ / cm ² ultraviolet rays using a low-pressure mercury lamp to decompose and harden peroxoic acid.
By heating at 0 ° C. for 30 minutes to decompose and anneal the hydroxypropylcellulose, a titanium oxide semiconductor layer (D) having a flat metal oxide semiconductor layer surface was formed.

Table 1 shows the thickness of the obtained titanium oxide semiconductor layer (D), the pore volume and the average pore diameter determined by the nitrogen adsorption method. Adsorption of spectral sensitizing dye In the same manner as in Example 1 , adsorption of the spectral sensitizing dye was performed on the metal oxide semiconductor layer (D).

Table 1 shows the adsorption amount of the spectral sensitizing dye. Preparation of photoelectric cell A photoelectric cell (D) was prepared in the same manner as in Example 1,
V _oc , J _oc , FF and η were measured and the results are shown in Table 1.

[0090]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a photoelectric cell according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing one example of a conductive projecting portion of the photoelectric cell according to the present invention.

FIG. 3 is an enlarged cross-sectional view showing one example of a conductive projecting portion of the photoelectric cell according to the present invention.

FIG. 4 is a schematic sectional view showing one embodiment of a photoelectric cell according to the present invention.

FIG. 5 is a schematic diagram showing a definition of a layer thickness.

[Explanation of symbols]

 1 ... Electrode layer 2 ... Metal oxide semiconductor layer 3 ... Transparent electrode layer 4 ... Electrical protrusion 5 ... Electrolyte 6 ... ..Insulating substrate 7 ... Transparent insulating substrate

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hirokazu Tanaka 13-2 Kitaminato-cho, Wakamatsu-ku, Kitakyushu-shi, Fukuoka Prefecture Inside the Wakamatsu Plant of Catalysts and Chemicals Co., Ltd. (72) Inventor Katsuhiro Jono Kitakyushu-shi, Fukuoka 13-2 Kitaminato-cho, Wakamatsu-ku Contact Fushiki Kasei Kogyo Co., Ltd. Wakamatsu Plant F-term (reference) 5F051 AA14 FA02 GA03

Claims (11)

[Claims] An electrode layer (1) is provided on the surface, and said electrode layer (1)
Metal oxide semiconductor layer with spectral sensitizing dye adsorbed on its surface (2)
And an insulating substrate having an electrode layer (3) on its surface, wherein the electrode layers (1) and (3) are arranged so as to face each other, and a metal oxide semiconductor layer An opto-electric cell in which an electrolyte is sealed between (2) and an electrode layer (3), comprising a conductive projection (4) projecting from the surface of the electrode layer (1), and a metal oxide semiconductor. A photovoltaic cell, wherein the layer is formed so as to cover the conductive projecting portion and the electrode layer (1), and at least one of the insulating substrate and the electrode layer has transparency. 2. The photovoltaic cell according to claim 1, wherein the metal oxide semiconductor layer is formed so as to conform to the shape of the conductive protrusion (4). 3. The method according to claim 1, wherein the metal oxide semiconductor layer comprises titanium oxide,
2. A spherical particle of at least one or two or more metal oxides selected from lanthanum oxide, zirconium oxide, niobium oxide, tungsten oxide, strontium oxide, zinc oxide, tin oxide, and indium oxide. Or the opto-electric cell according to 2. 4. The spherical particles have an average particle diameter of 5 to 600.
The opto-electric cell according to claim 3, characterized in the range of nm. 5. The photovoltaic cell according to claim 4, wherein said spherical particles are made of anatase type titanium oxide. 6. The spherical particles having an average particle size of 0.1 to 5
The photoelectric cell according to claim 4, wherein the particle is a spherical particle having a core-shell structure in which a shell part is formed on the surface of a core particle of 00 nm. 7. The photovoltaic cell according to claim 6, wherein the shell of the spherical particles having the core-shell structure is made of anatase type titanium oxide. 8. The photovoltaic cell according to claim 5, wherein said anatase type titanium oxide is obtained by heating and aging peroxotitanic acid. 9. The photovoltaic cell according to claim 3, wherein said metal oxide semiconductor layer contains a titanium oxide binder together with metal oxide spherical particles. 10. The method according to claim 10, wherein the metal oxide semiconductor layer is formed of O ₂ , N ₂ ,
After implanting at least one ion selected from gases H ₂ and Periodic Table Group 0 inert gas, according to claim, characterized in that it is an annealed 3-9
The photoelectric cell according to any one of the above. 11. The metal oxide semiconductor layer has a pore volume of 0.05 to 0.8 ml / g and an average pore diameter of 2 to 250 n.
The photoelectric cell according to any one of claims 1 to 10, wherein m is in the range of m.