JP4176200B2 - Photoelectric cell - Google Patents

Description

【図面の簡単な説明】
【図１】 本発明に係るに光電気セルの一実施例を示す概略断面図である。
【図２】 本発明に係るに光電気セルの導電性突設部の１例を示す拡大断面図である。
【図３】 本発明に係るに光電気セルの導電性突設部の１例を示す拡大断面図である。
【図４】 本発明に係るに光電気セルの一実施例を示す概略断面図である。
【図５】 層厚の定義を表す模式図。
【符号の説明】
１・・・・・電極層
２・・・・・金属酸化物半導体層
３・・・・・透明電極層
４・・・・・導電性突設部
５・・・・・電解質
６・・・・・絶縁性基板
７・・・・・透明絶縁性基板[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a photoelectric cell having a high adsorption / loading amount of a spectral sensitizing dye to a metal oxide semiconductor layer, a high bonding force between the metal oxide semiconductor layer and the spectral sensitizing dye, and an improved photoelectric conversion efficiency. .
[0002]
TECHNICAL BACKGROUND OF THE INVENTION
The photoelectric conversion material is a material that can continuously extract light energy as electric energy, and is a material that converts light energy into electric energy using 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 example, for solar cells.
[0003]
In general solar cells, first a semiconductor film for photoelectric conversion material is formed on a support such as a glass plate coated with a transparent conductive film as an electrode, and then another transparent conductive film is used as a counter electrode. A support such as a coated glass plate is provided, and an electrolyte is sealed between these electrodes.
[0004]
When the spectral sensitizing dye adsorbed on the photoelectric conversion material semiconductor is irradiated with sunlight, the spectral sensitizing dye absorbs light in the visible region and is excited. The electrons generated by this excitation move to the semiconductor, then move to the transparent conductive glass electrode, move to the counter electrode through the conducting wire 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 having electrons transferred to the semiconductor is in an oxidant state, but this oxidant is reduced by the redox system in the electrolyte and returns to its original state. In this way, electrons flow continuously, and the photoelectric conversion material functions as a solar cell.
[0005]
As this photoelectric conversion material, a material obtained by adsorbing a spectral sensitizing dye having absorption in the visible light region on the semiconductor surface is used. For example, Japanese Patent Laid-Open No. 1-220380 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. JP-T-5-504023 discloses 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 solar cell as described above, it is important for improving the light conversion efficiency that the electron transfer from the spectral sensitizing dye layer excited by absorbing light to the titania film is important, and the electron transfer is performed quickly. Otherwise, there is a problem that the recombination of the ruthenium complex and the electrons occurs again and the light conversion efficiency is lowered.
[0007]
For this reason, it has been studied to increase the amount of adsorption between the titania film surface 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 titania sol is applied on an electrode substrate, dried, and then fired repeatedly to form a porous thick film, and the semiconductor film is made porous. It has been proposed to increase the amount of Ru complex supported on the surface. It has also been proposed to improve conductivity by firing between titania fine particles at a temperature of 400 ° C. or higher. Further, Japanese Patent Publication No. 6-511113 proposes to immerse in an aqueous solution of titanium chloride or electrochemically deposit it on a titania film using a hydrolyzed solution of titanium chloride in order to increase the effective surface. .
[0008]
However, in these methods, the titanium oxide semiconductor film is baked in order to improve the electron mobility. For this reason, the porosity (effective surface) is lowered by the sintering of the particles, and the adsorption amount of the spectral sensitizing dye is decreased. However, the photoelectric conversion efficiency is not always sufficient, the use is limited, and further improvement has been desired.
[0009]
OBJECT OF THE INVENTION
An object of the present invention is to provide a photoelectric cell in which the amount of spectral sensitizing dye adsorbed in a semiconductor layer is high and the photoelectric conversion efficiency is improved.
[0010]
SUMMARY OF THE INVENTION
The photovoltaic cell according to the present invention comprises:
An insulating substrate having 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 having an electrode layer (3) on the surface,
The electrode layers (1) and (3) are arranged so as to face each other,
In the photoelectric cell in which an electrolyte is sealed between the metal oxide semiconductor layer (2) and the electrode layer (3),
The electrode layer (1) has a conductive protrusion (4) protruding on the surface, and the metal oxide semiconductor layer is formed to cover the conductive protrusion (4) and the electrode layer (1). ,
It is characterized in that at least one of the insulating substrate and the electrode layer has transparency.
[0011]
The metal oxide semiconductor layer is preferably formed so as to follow the shape of the conductive protruding portion (4).
The metal oxide semiconductor layer may include at least one 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 that spherical particles are included.
[0012]
The average particle diameter of the spherical particles is preferably in the range of 5 to 600 nm. Such spherical particles are preferably made of anatase-type titanium oxide. 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 a metal oxide core particle having an average particle diameter of 0.1 to 500 nm. In the spherical particles having such a core-shell structure, the shell portion is particularly preferably anatase type titanium oxide.
[0013]
The anatase-type titanium oxide is preferably obtained by heating and aging peroxotitanic acid.
Further, the metal oxide semiconductor layer may contain a titanium oxide binder together with the metal oxide spherical particles.
[0014]
Furthermore, the metal oxide semiconductor layer is made of O₂, N₂, H₂In addition, it is preferable that the gas is annealed after implanting ions of at least one gas selected from an inert gas belonging to Group 0 of the periodic table.
[0015]
In the photoelectric cell according to the present invention, the formed metal oxide semiconductor layer preferably has a pore volume of 0.05 to 0.8 ml / g and an average pore diameter 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 (1) on the surface, and an insulating property formed by forming a metal oxide semiconductor layer (2) adsorbing a spectral sensitizing dye on the surface of the electrode layer (1) A substrate,
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,
In the photoelectric cell in which an electrolyte is sealed between the metal oxide semiconductor layer (2) and the electrode layer (3),
The electrode layer (1) has a conductive protrusion (4) protruding on the surface, and the metal oxide semiconductor layer is formed so as to cover the conductive protrusion (4).
It is characterized in that at least one of the insulating substrate and the electrode layer has transparency.
[0017]
An example of such a photoelectric cell is shown in FIG.
FIG. 1 is a schematic cross-sectional view showing an embodiment of a photovoltaic cell according to the present invention, which has an electrode layer 1 on the surface of an insulating substrate 6 and a conductive protruding portion protruding on the surface of the electrode layer 1. 4 and an insulating substrate formed by covering the conductive protrusion 4 with the metal oxide semiconductor layer 2 having adsorbed the spectral sensitizing dye,
A transparent insulating substrate having the transparent electrode layer 3 on the surface of the transparent insulating substrate 7;
The electrode layers 1 and 3 are arranged so as to face each other,
Further, an electrolyte 5 is sealed between the metal oxide semiconductor layer 2 and the transparent electrode layer 3.
[0018]
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.
[0019]
Examples of the material constituting the electrode layer 1 formed on the surface of the insulating substrate 6 and the conductive protrusion 4 protruding from the surface of the electrode layer 1 include tin oxide, tin oxide doped with Sb, F or P, and indium oxide. Conventionally known conductive materials such as noble metals such as indium oxide, antimony oxide and platinum doped with Sn and / or F can be used. The electrode layer 1 and the conductive protrusion 4 may be formed from the same conductive material or different conductive materials.
[0020]
The shape of the conductive projecting portion is not limited to a rectangular parallelepiped shape as shown in FIG. 1, and may be a belt shape, a mesh shape, or the like.
The electrode layer 1 and the conductive protrusion 4 are electrically connected. The formation method of such an electrode layer 1 and the conductive protrusion 4 is not particularly limited. For example, after forming an electrode film on an insulating substrate by a thermal decomposition method, a CVD method, a vapor deposition method, etc., the film A method of etching the resist by applying a resist on the surface, patterning the conductive protrusions 4 and the like can be mentioned.
[0021]
Moreover, after forming the electrode layer 1 by CVD method, vapor deposition method, etc., the coating liquid containing the conductive particles made of the conductive material is applied to form the conductive particle layer, thereby forming the conductive protrusion 4. You may do it (FIG. 2). After applying a coating liquid containing conductive particles made of the above conductive material and forming a conductive particle layer so as to be densely packed, a resist is applied to the surface of the layer, and patterning of the conductive protrusion 4 is performed. Then, the conductive protrusion 4 can be formed by etching the resist (FIG. 3).
[0022]
It is preferable that the conductive protrusions 4 are located apart from each other by at least twice the average thickness of the metal oxide semiconductor layer 2. Moreover, it is desirable that the height of the conductive protrusion 4 is in the range of 20% to 98% of the thickness of the metal oxide semiconductor layer including the conductive protrusion 4. Within such a range, the electrons in the metal oxide semiconductor layer quickly move 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 rate to the electrode layer 1 is insufficient, and if it exceeds 98%, it may be electrically connected to the electrolyte.
[0023]
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, indium oxide doped with Sn and / or F, oxide A transparent electrode such as antimony 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, or a vapor deposition method can be employed.
[0024]
The visible light transmittance of the insulating substrate 6 and the electrode layer 3 is preferably as high as possible, specifically 50% or more, particularly preferably 90% or more. When the visible light transmittance is less than 50%, the photoelectric conversion efficiency is low, which is not preferable.
[0025]
In the photoelectric cell according to the present invention, it is only necessary that at least one of the insulating substrate and the electrode layer is transparent. For this reason, it is not limited to the photoelectric cell as shown in FIG. 1, and for example, the insulating substrate 6, the electrode layer 1 and the conductive protrusion 4 may be transparent, and the insulating substrates 6 and 7, the electrodes The layers 1 and 3 and the conductive protruding portion 4 may all be transparent.
[0026]
The resistance values of the electrode layers 1 and 3 and the conductive protrusion 4 are usually 50 Ω / cm, respectively.²The following is preferable. The resistance value of the electrode layer is 50 Ω / cm²Similarly, the photoelectric conversion efficiency may be lowered when the value is higher than the above value.
[0027]
In the photoelectric 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 have the conductive projecting portion 4 embedded therein or may be formed so as to follow the shape formed of the electrode layer 1 and the conductive projecting portion 4.
[0028]
In particular, as shown in FIG. 4, it is desirable that the metal oxide semiconductor layer is formed so as to follow a shape including the electrode layer 1 and the conductive protrusion 4. When formed in this manner, the electrolyte intrudes into the metal oxide semiconductor layer, increasing the contact area between the metal oxide semiconductor layer and the electrolyte, increasing the amount of received light, and the amount of spectral sensitizing dye adsorption. The photoelectric conversion efficiency is increased due to an increase.
[0029]
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 the metal oxide formed on the conductive protrusion or on the electrode layer surface The thickness of the semiconductor layer is preferably in the range of 0.1 to 50 μm.
[0030]
Note that, as shown in FIG. 5, the average thickness of the metal oxide semiconductor layer means an average value of the thickness of the metal oxide semiconductor layer including the conductive protrusions, and is a film of the metal oxide semiconductor layer. The thickness is the thickness of the oxide semiconductor layer provided on the surface of the electrode layer 1 and the conductive protrusion 4. Moreover, it is preferable that the depth (the depth of the electrolyte penetration portion) where the electrolyte enters the metal oxide semiconductor layer is within a range of 20% to 90% of the thickness of the metal oxide semiconductor layer. If the depth of the electrolyte intrusion is less than 20%, the effect of increasing the amount of received light is not sufficient, and if it exceeds 90%, the strength of the metal oxide semiconductor layer may be insufficient.
[0031]
Examples of such metal oxide semiconductor layers include metal oxides composed of spherical particles of metal oxides such as titanium oxide, lanthanum oxide, zirconium oxide, niobium oxide, tungsten oxide, strontium oxide, zinc oxide, tin oxide, and indium oxide. A semiconductor layer is preferred.
[0032]
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, a uniform surface state can be obtained with spherical particles. For this reason, electron transfer from the spectral sensitizing dye to the metal oxide semiconductor layer is efficiently performed, and as a result, electron mobility is improved. The particle diameter of the metal oxide particles can be measured with a laser Doppler particle size measuring instrument (manufactured by Nikkiso Co., Ltd .: Microtrac). When the average particle diameter of the metal oxide particles is less than 5 nm, the formed metal oxide semiconductor layer is likely to crack, and the metal oxide semiconductor layer is formed in a small number of times without cracks. In some cases, the pore diameter and pore volume of the metal oxide semiconductor layer are lowered, and the amount of adsorption of the spectral sensitizing dye may be lowered. In addition, when the average particle diameter of the metal oxide particles is larger than 600 nm, the strength of the metal oxide semiconductor layer may be insufficient.
[0033]
As such metal oxide spherical particles, spherical particles made of anatase-type titanium oxide are preferable.
Anatase-type titanium oxide particles can be obtained by adding alkali to peroxotitanic acid, preferably ammonia and / or amine to make it alkaline, and then heating and aging in a temperature range of 80 to 350 ° C. In addition, after adding peroxotitanic acid using the obtained anatase-type titanium colloidal particles as seed particles, it is possible to repeat the above-mentioned process, and the method of growing seed particles in this way is crystalline by X-ray diffraction. This is preferable because colloidal particles of high anatase type titanium can be obtained. “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.
[0034]
The hydrated titanium oxide sol or gel is obtained by adding an acid or alkali to an aqueous solution of a titanium compound to hydrolyze it, and washing, heating and aging as necessary. Although there is no restriction | limiting in particular as a titanium compound used, Titanium compounds, such as titanium halides, such as a halogenated titanium and a titanyl sulfate, titanium alkoxides, such as tetraalkoxy titanium, and a titanium hydride can be used.
[0035]
Further, in the present invention, as the metal oxide spherical particles, there are also spherical particles having a core-shell structure having cells made of the metal oxide on the surface of the metal oxide core particles having an average particle diameter in the range of 0.1 to 500 nm. Preferably used. In the case of a spherical particle having a core-shell structure, the core particle is not particularly limited as long as it is a spherical particle, but a silica particle or the like from which a true spherical particle can be easily obtained is 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, and particularly preferably anatase type titanium oxide.
[0036]
The spherical particles having such a core-shell structure can be obtained by gradually adding peroxotitanic acid to a dispersion of core particles in the particle diameter range, if necessary, by heating.
[0037]
If 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, and the metal oxidization from the spectral sensitizing dye It has excellent characteristics such as high electron mobility to a physical semiconductor and high electron mobility in a metal oxide semiconductor layer, and further stability, safety, and film formation.
[0038]
The preferable range of the crystallite size of such anatase type titanium oxide is 5 to 50 nm, and the more preferable range is 7 to 30 nm. The crystallite size of anatase-type titanium oxide is obtained by measuring the full width at half maximum of the (1.0.1) plane peak by X-ray diffraction and calculating the Debye-Scherrer equation. When the crystallite size of the anatase-type titanium oxide particle is less than 5 nm, the electron mobility in the particle is lowered, and when it is larger than 50 nm, the adsorption amount of the spectral sensitizing dye is lowered and the photoelectric conversion efficiency is lowered. Sometimes.
[0039]
The metal oxide semiconductor layer may contain a binder component together with the spherical particles of the metal oxide.
Examples of such binder components include amorphous titanium oxide obtained by the sol-gel method, peroxotitanic acid obtained by dissolving particles obtained by the sol-gel method with hydrogen peroxide, and hydrolyzing / condensing this peroxotitanic acid. Examples thereof include amorphous titanium oxide obtained by polymerization. Of these, amorphous titanium oxide obtained by hydrolysis / condensation polymerization of the peroxotitanic acid is particularly preferable. When spherical particles having an anatase-type titanium oxide particle or a core-shell structure in which the shell portion is formed of anatase-type titanium acid are used as the spherical particles, such hydrolyzed / condensed polymer of peroxotitanic acid is A dense and uniform adsorption layer is formed on the surface of the anatase-type titanium oxide particles. For this reason, the metal oxide semiconductor layer obtained can improve adhesiveness with an electrode. Furthermore, when such peroxotitanic acid is used as a binder component, contact between anatase-type titanium oxide particles is changed from point contact to surface contact, and electron mobility can be improved.
[0040]
The ratio of amorphous titanium oxide to metal oxide spherical particles in the metal oxide semiconductor layer is 0.05 to 0.7, preferably by weight ratio in terms of oxide (amorphous titanium oxide / metal oxide spherical particles), preferably It is preferable to be in the range of 0.1 to 0.5. When 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, the pore diameter of the generated pores is too small, so that the transfer of electrons between the electrolyte and the spectral sensitizing dye tends to be suppressed. May not improve.
[0041]
The metal oxide semiconductor layer preferably has a pore volume of 0.05 to 0.8 ml / g and an average pore diameter of 2 to 250 nm. When the pore volume is smaller than 0.05 ml / g, the spectral sensitizing dye adsorption amount is low, and when it is higher than 0.8 ml / g, the electron mobility in the layer is lowered and the photoelectric conversion efficiency is reduced. May decrease. 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 may decrease and the photoelectric conversion efficiency may decrease.
[0042]
Such a metal oxide semiconductor layer is formed by applying a coating liquid for forming a metal oxide semiconductor layer for photoelectric cells containing metal oxide spherical particles, a dispersion medium, and, if necessary, a binder, and then drying. Can be formed.
[0043]
The dispersion medium can be used without particular limitation as long as it can disperse the metal oxide particles and the binder component and can be removed when dried, but alcohols are particularly preferable.
[0044]
Further, this coating solution may contain a forming aid as required. Examples of the forming aid include polyethylene glycol, polyvinyl pyrrolidone, hydroxypropyl cellulose, polyacrylic acid, and polyvinyl alcohol.
[0045]
When such a forming aid is contained in the coating solution, the viscosity of the coating solution becomes high, whereby a uniformly dried layer is obtained, and the anatase-type titanium oxide particles are densely packed, and the electrode It is possible to obtain a metal oxide semiconductor layer having high adhesiveness.
[0046]
The coating solution is preferably applied such that the finally formed metal oxide semiconductor layer has a thickness of 0.1 to 50 μm. As a coating method of the coating solution, 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, or a transfer method.
[0047]
The drying temperature may be any temperature that can remove the dispersion medium. After drying, if necessary, ultraviolet rays may be further irradiated to cure peroxotitanic acid contained as a binder component. Although the irradiation amount of ultraviolet rays varies depending on the content of peroxotitanic acid and the like, it is sufficient to irradiate the amount necessary to decompose and cure peroxotitanic acid. In addition, when the shaping | molding adjuvant is contained, you may decompose | disassemble a formation adjuvant by heat-processing after hardening.
[0048]
In addition, the formed metal oxide semiconductor layer includes O₂, N₂, H₂It is preferable to implant ions of at least one gas selected from an inert gas of Group 0 of the periodic table such as neon, argon, krypton, and then anneal. As an ion implantation method, a known method can be employed as a method of implanting B or P into a silicon wafer at a certain amount and a certain depth when manufacturing an IC or LSI.
[0049]
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. Depending on 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, and the crystallinity after annealing is improved and Bonding is promoted, which increases the binding force with the spectral sensitizing dye and increases the amount of adsorption. In the case of titanium oxide particles, the crystal mobility is improved and the electron mobility is improved by promoting the bonding of the particles. Since photoelectric conversion efficiency improves, it is preferable.
[0050]
In the photoelectric 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 the visible light region and / or infrared light region. For example, an organic dye or a metal complex can be used.
[0051]
As the organic dye, a conventionally known organic dye having a functional group such as a carboxyl group, a hydroxyalkyl group, a hydroxyl group, a sulfone group, or a carboxyalkyl group in the molecule can be used. Specific examples include metal-free phthalocyanines, cyanine dyes, methocyanine dyes, triphenylmethane dyes, and xanthene dyes such as uranin, eosin, rose bengal, rhodamine B, and dibromofluorescein. These organic dyes have the property that the adsorption rate to the metal oxide semiconductor is fast.
[0052]
Examples of the metal complex include metal phthalocyanines such as copper phthalocyanine and titanyl phthalocyanine described in JP-A-1-220380 and JP-A-5-504023, chlorophyll, hemin, ruthenium-tris (2,2 ′ -Bispyridyl-4,4'-dicarboxylate), ruthenium-cis-diaqua-bis (2,2'-bipyridyl-4,4'-dicarboxylate), which ruthenium-cis-diaqua-bipyridyl complex, zinc-tetra Examples include porphyrins such as (4-carboxyphenyl) porphine, and ruthenium, osmium, iron, zinc and the like complexes such as iron-hexocyanide complexes. These metal complexes are excellent in the effect of spectral sensitization and durability.
[0053]
The above organic dyes and metal complexes may be used singly or in combination of two or more, and organic dyes and metal complexes may be used in combination.
Such a method for adsorbing spectral sensitizing dyes is not particularly limited, and a general method such as absorption of a solution obtained by dissolving spectral sensitizing dyes in a solvent into a metal oxide semiconductor layer and then drying can be employed. Furthermore, you may repeat the said process as needed. Further, the spectral sensitizing dye solution can be adsorbed by being brought into contact with the substrate while being heated and refluxed.
[0054]
Any solvent may be used as long as it can dissolve spectral sensitizing dyes. Specifically, water, alcohols, toluene, dimethylformamide, chloroform, ethyl cellosolve, N-methylpyrrolidone, tetrahydrofuran, and the like can be used. .
[0055]
The amount of spectral sensitizing dye adsorbed on the metal oxide semiconductor layer is 1 cm of the specific surface area of the metal oxide semiconductor layer.²It is preferably 100 μg or more per unit. When the amount of the spectral sensitizing dye is less than 100 μg, the photoelectric conversion efficiency may be insufficient.
[0056]
The photoelectric cell according to the present invention is formed by disposing 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 enclosing an electrolyte between the electrodes. As the electrolyte 5, a mixture with at least one compound that forms a redox system with an electrochemically active salt is used.
[0057]
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, and potassium bromide.
[0058]
Moreover, in this invention, it can be set as electrolyte solution using a solvent for the said electrolyte 5 as needed. The solvent used at this time is preferably a solvent having a low solubility of the spectral sensitizing dye to such an extent that the spectral sensitizing dye adsorbed on the metal oxide semiconductor layer is not desorbed and dissolved. Specific examples of solvents include water, alcohols, oligoethers, carbonates such as propion carbonate, phosphate esters, dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, N-vinylpyrrolidone, sulfolane 66, sulfur compounds, and carbonic acid. Examples include ethylene and acetonitrile.
[0059]
In such a photoelectric cell of the present invention, since the specific conductive protrusion is provided on the electrode surface, the generated electrons can quickly move to the electrode. Also, the electrons do not recombine with the spectral sensitizing dye. Furthermore, the photoelectric cell according to the present invention has a high adsorption amount of the spectral sensitizing dye, and the generated electrons can move smoothly. For this reason, the photoelectric cell according to the present invention is excellent in photoelectric conversion efficiency.
【The invention's effect】
According to the present invention, a photoelectric cell having high photoelectric conversion efficiency and useful for various photoelectric conversion applications such as a solar battery can be obtained.
[0060]
【Example】
Hereinafter, although an example explains, the present invention is not limited by these examples.
[0061]
[Example 1]
Preparation of coating solution
Suspend 5 g of titanium hydride in 1 liter of pure water, add 400 g of hydrogen peroxide solution with a concentration of 5% by weight over 30 minutes, and then dissolve by heating to 80 ° C. to prepare a solution of peroxotitanic acid did. 90% by volume was taken from the total amount of this solution, adjusted to pH 9 by adding concentrated aqueous ammonia, placed in an autoclave, hydrothermally treated at 250 ° C. for 5 hours under saturated vapor pressure, and titania colloidal particles (A) Was prepared. The obtained titania colloidal particles were anatase type titanium oxide having high crystallinity by X-ray diffraction. Table 1 shows the average particle diameter of the anatase-type titanium oxide particles.
[0062]
Next, the titania colloidal particles (A) obtained above are concentrated to a concentration of 10% by weight, the peroxotitanic acid solution is mixed, and the titanium in the mixture is converted to TiO2.₂Converted to TiO₂Hydroxypropyl cellulose was added as a forming aid so as to be 30% by weight of the weight to prepare a coating solution for forming a metal oxide semiconductor layer.
[0063]
Electrode formation
The photoelectric cell shown in FIG. 1 was formed.
Using a magnet sputtering device (manufactured by Shimadzu Corporation: HSR-521A) on one side of the transparent glass substrate 5, with fluorine-doped tin oxide as a target, RF Power: 500 W, Ar gas (10 sccm), 0.04 torr, A fluorine-doped tin oxide film having a thickness of 5 μm was formed under the conditions of 200 min and a substrate temperature of 250 ° C. Next, a resist (manufactured by Tokyo Ohka Co., Ltd .: OFPR-800) was applied on this film, and then patterning of Line & Space with a pitch of 2 μm was performed. Next, using a reactive ion etching RIE system (Anelva DEM451T), RF Power: 500W, BCl_Three (40 sccm) and Ar (10 sccm) gas 10 Pa is etched, and then the resist is removed by ashing to form an electrode layer 1 having a thickness of 0.5 μm and a conductive protrusion 4 having a height of 4.5 μm. Formed.
[0064]
On one side of another transparent glass substrate 6, using a magnet sputtering device (manufactured by Shimadzu Corporation: HSR-521A), with fluorine-doped tin oxide as a target, RF Power: 500 W, Ar gas (10 sccm), 0.04 Under the conditions of torr and 20 min, a fluorine-doped tin oxide layer having a thickness of 0.5 μm was formed, and platinum was supported thereon to form the electrode layer 3.
[0065]
Next, the prepared coating liquid for forming a metal oxide semiconductor layer is applied onto the electrode layer 1 made of fluorine-doped tin oxide and the conductive projecting portion 4, dried naturally, and subsequently 6000 mJ using a low-pressure mercury lamp. /cm²The ultraviolet rays were irradiated to decompose the peroxoacid and the layer was cured. Furthermore, it decomposed | disassembled and annealed by heating for 30 minutes at 300 degreeC, and the titanium oxide semiconductor layer (A) whose metal oxide semiconductor layer surface is flat was formed.
[0066]
Table 1 shows the layer thickness of the obtained titanium oxide semiconductor layer (A) and the pore volume and average pore diameter determined by the nitrogen adsorption method.
Spectral sensitizing dye adsorption
Next, as a spectral sensitizing dye, cis- (SCN^-) -Bis (2,2'-bipyridyl-4,4'-dicarboxylate) ruthenium (II)^-FourA mol / liter ethanol solution 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 of the obtained titanium oxide semiconductor layer (A) is 1 cm in specific surface area of the titanium oxide semiconductor layer (A).²The adsorption amount per unit is shown in the table.
[0067]
First, tetrapropylammonium iodide and iodine are mixed in a solvent in which acetonitrile and ethylene carbonate are mixed at a volume ratio of 1: 4, and the respective concentrations are 0.46 mol / liter and 0.06 mol / liter. The electrolyte solution was prepared by dissolving so as to be.
[0068]
The electrode layer 1 prepared as described above and the transparent glass substrate 5 on which the conductive protrusions 4 are formed are used as one electrode, the transparent glass substrate 6 on which the electrode layer 2 is formed are arranged as the other electrode, and the side surfaces are arranged. The electrode was sealed with resin, the electrolyte solution 2 was sealed between the electrodes, and the electrodes were connected with lead wires to prepare a light electric cell (A).
[0069]
Photoelectric cell (A) is a solar simulator, 100 W / m²Is irradiated with light of the intensity V_oc(Open circuit voltage), J_oc(Density of current flowing when the circuit is short-circuited), FF (curve factor) and η (conversion efficiency) were measured, and the results are shown in Table 1.
[0070]
[Example 2]
The concentration of the coating solution for forming a metal oxide semiconductor layer prepared in Example 1 was diluted with water so that the concentration would be 1/3 to prepare a coating solution for forming a metal oxide semiconductor layer (titania colloidal particles ( A) concentration 3_.3% by weight, hydroxypropylcellulose is titanium in the liquid TiO₂Converted to TiO₂10% by weight of the weight).
[0071]
After applying the prepared coating liquid for forming a metal oxide semiconductor layer on the electrode layer 1 made of fluorine-doped tin oxide and the conductive projecting portion 4 as in Example 1, using this coating liquid, The operation of rapid drying was carried out in six steps, and a titanium oxide semiconductor layer was formed so as to have an electrolyte part that had penetrated into the same metal oxide semiconductor layer as in Example 1.
[0072]
Next, using a low-pressure mercury lamp, 6000 mJ / cm²Was irradiated with UV light to decompose the peroxo acid, and the titanium oxide semiconductor layer was cured. Furthermore, the titanium oxide semiconductor layer (B) having a flat metal oxide semiconductor layer surface was formed by heating and heating at 300 ° C. for 30 minutes to decompose and anneal hydroxypropylcellulose.
[0073]
Table 1 shows the layer thickness of the obtained titanium oxide semiconductor layer (B) and the pore volume and average pore diameter determined by the nitrogen adsorption method.
Spectral sensitizing dye adsorption
In the same manner as in Example 1, the spectral sensitizing dye was adsorbed on the titanium oxide layer.
[0074]
The adsorption amount of the spectral sensitizing dye is shown in Table 1.
Photoelectric cell creation
A photoelectric cell (B) was prepared in the same manner as in Example 1, and V_oc, J_oc, FF and η were measured and the results are shown in Table 1.
[0075]
[Comparative Example 1]
Using a magnet sputtering device (manufactured by Shimadzu Corp .: HSR-521A) on one side of the transparent glass substrate 5, with fluorine-doped tin oxide as a target, RF Power: 500 W, Ar gas (10 sccm) 0.04 torr, 20 min Under the conditions, an electrode layer 1 of fluorine-doped tin oxide having a thickness of 0.5 μm was formed.
[0076]
On one side of another transparent glass substrate 6, RF power: 500 W, Ar gas (10 sccm) using a magnet sputtering apparatus (manufactured by Shimadzu Corporation: HSR-521A) and targeting fluorine-doped tin oxide. Under the conditions of 04 torr and 20 min, a 0.5 μm-thick fluorine-doped tin oxide layer was formed, and platinum was supported thereon to form an electrode layer 3.
[0077]
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.
Table 1 shows the layer thickness of the obtained titanium oxide semiconductor layer (C) and the pore volume and average pore diameter determined by the nitrogen adsorption method.
[0078]
Spectral sensitizing dye adsorption
In the same manner as in Example 1, the spectral sensitizing dye was adsorbed on the titanium oxide layer (C).
The adsorption amount of the spectral sensitizing dye is shown in Table 1.
[0079]
Photoelectric cell creation
A light electric cell (C) is prepared in the same manner as in Example 1, and V_oc, J_oc, FF and η were measured and the results are shown in Table 1.
[0080]
[Example 3]
Preparation of particles having a core-shell structure
Dispersion of spherical silica particles having an average particle size of 0.2 μm by adding a mixed solution of 7.6 g of tetraethoxysilane and 100 g of ethanol to a mixed solution of 200 g of ethanol, 25 g of pure water and 60 g of ammonia water having a concentration of 29% by weight. A liquid was prepared. The obtained dispersion liquid was then used to obtain a silica particle dispersion liquid (core particles) concentrated to a silica concentration of 10% by weight using a rotary evaporator.
[0081]
5_.Suspend 5 g of titanium hydride in 1 liter of pure water, add 400 g of hydrogen peroxide solution with a concentration of 5% by weight over 30 minutes, and then dissolve by heating to 80 ° C. to prepare a solution of peroxotitanic acid did.
[0082]
The previously prepared silica particle dispersion is heated to 90 ° C., and a solution of peroxotitanic acid is added to this in 100 hours to disperse the metal oxide particles (D) in which the core is silica and the shell is titanium oxide. Was prepared. As for the obtained metal oxide particle (D), the titanium oxide of the shell part was anatase type titanium oxide by X-ray diffraction. In addition, Table 1 shows the average particle diameter of the metal oxide particles (D).
[0083]
Photoelectric cell formation
Using a magnet sputtering device (manufactured by Shimadzu Corporation: HSR-521A) on one side of the transparent glass substrate 5, with a fluorine-doped tin oxide target, RF Power: 500 W, Ar gas (10 sccm) 0.04 torr, The electrode layer 1 of fluorine-doped tin oxide having a thickness of 0.5 μm was formed under the condition of 20 min.
[0084]
On one side of another transparent glass substrate, RF power: 500 W, Ar gas (10 sccm) 0.04 torr using a magnet sputtering device (manufactured by Shimadzu Corporation: HSR-521A) and targeting fluorine-doped tin oxide Then, a fluorine-doped tin oxide layer having a thickness of 0.5 μm was formed under the condition of 20 min, and platinum was supported on this layer to form the electrode layer 3.
[0085]
A negative photoresist (manufactured by Tokyo Ohka Kogyo Co., Ltd .: OMR-83) was spin-coated at 500 rpm on the electrode layer 1 to form a resist film having a thickness of 6 μm. Subsequently, development was performed after exposure with an aligner, and patterning of Line & Space with a pitch of 6 μm was performed.
[0086]
Next, the transparent glass substrate on which the patterned electrode layer 1 is formed is immersed in a dispersion of metal oxide particles (D), a platinum electrode is used as a counter electrode, a positive voltage is applied to the transparent glass substrate, and Metal oxide particles (D) were laminated. Then, spin-coating peroxotitanic acid prepared separately on the metal oxide particle (D) layer so that the weight ratio as an oxide with respect to the metal oxide particle (D) is 0.15, and naturally drying, Continue using a low-pressure mercury lamp to 6000mJ / cm²Was irradiated with UV light to decompose the peroxo acid, and the metal oxide semiconductor layer was cured. After curing, O₂-Ashing to remove the resist. Next, an indium colloidal particle dispersion (catalyst conversion: ARS-22A, particle size 0.07 μm, concentration 2.5 wt%) is spin coated and removed at the same height as the metal oxide particle (D) layer. The conductive protrusion 4 was formed by filling indium colloidal particles.
[0087]
Next, in the dispersion of the metal oxide particles (D) having a concentration of 10% obtained in the same manner as described above, the weight ratio of the peroxotitanic acid solution to the metal oxide particles (D) as an oxide is 0.00. 15 is mixed, and hydroxypropyl cellulose is added as a forming aid so as to be 30% by weight with respect to the weight of the metal oxide in the mixed solution to prepare a coating solution for forming a metal oxide semiconductor layer. Then, this is applied onto the conductive protrusion 4 made of the metal oxide particle (D) layer and the indium colloidal particles, dried again naturally, and subsequently 6000 mJ / cm using a low-pressure mercury lamp.²The titanium oxide semiconductor layer (the surface of the metal oxide semiconductor layer having a flat surface is obtained by decomposing and curing the peroxo acid by irradiation with ultraviolet rays of, and further heating and heating at 300 ° C. for 30 minutes to decompose and anneal the hydroxypropyl cellulose. D) was formed.
[0088]
Table 1 shows the thickness of the obtained titanium oxide semiconductor layer (D) and the pore volume and average pore diameter determined by the nitrogen adsorption method.
Spectral sensitizing dye adsorption
In the same manner as in Example 1, the spectral sensitizing dye was adsorbed on the metal oxide semiconductor layer (D).
[0089]
The adsorption amount of the spectral sensitizing dye is shown in Table 1.
Photoelectric cell creation
A photoelectric cell (D) was prepared in the same manner as in Example 1, and 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 an embodiment of a photoelectric cell according to the present invention.
FIG. 2 is an enlarged cross-sectional view showing an example of a conductive projecting portion of a photoelectric cell according to the present invention.
FIG. 3 is an enlarged cross-sectional view showing an example of a conductive projecting portion of a photoelectric cell according to the present invention.
FIG. 4 is a schematic cross-sectional view showing an embodiment of a photoelectric cell according to the present invention.
FIG. 5 is a schematic diagram showing the definition of layer thickness.
[Explanation of symbols]
1 ... Electrode layer
2 ... Metal oxide semiconductor layer
3. Transparent electrode layer
4 ... Conductive protrusion
5 ... Electrolyte
6. Insulating substrate
7: Transparent insulating substrate

Claims (12)

An insulating substrate having 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), and an electrode layer ( 3) is disposed such that the electrode layers (1) and (3) face each other, and an electrolyte is provided between the metal oxide semiconductor layer (2) and the electrode layer (3). In an encapsulated photoelectric cell,
Electrode layer (1) electrically conductive projecting portion (4) is formed to protrude on the surface, the conductive projecting portion (4)
The height is in the range of 20% to 98% of the thickness of the metal oxide semiconductor layer including the conductive protrusions 4;
And the metal oxide semiconductor layer is formed so as to cover the conductive protrusion and the electrode layer (1),
A photovoltaic cell, wherein at least one of the insulating substrate and the electrode layer has transparency. The photoelectric cell according to claim 1, wherein the metal oxide semiconductor layer is formed so as to follow the shape of the conductive protrusion (4).   The metal oxide semiconductor layer is a sphere 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. Photoelectric cell according to claim 1 or 2, characterized in that it comprises particles.   The photoelectric cell according to claim 3, wherein the spherical particles have an average particle diameter in the range of 5 to 600 nm.   The photoelectric cell according to claim 4, wherein the spherical particles are made of anatase-type titanium oxide.   5. The photoelectric device according to claim 4, wherein the spherical particles are spherical particles having a core-shell structure in which a shell portion is formed on a surface of a core particle having an average particle diameter of 0.1 to 500 nm. cell.   The photoelectric cell according to claim 6, wherein the shell part of the spherical particles having the core-shell structure is made of anatase type titanium oxide.   The photoelectric cell according to claim 5, wherein the anatase-type titanium oxide is obtained by heating and aging peroxotitanic acid.   The photoelectric cell according to claim 3, wherein the metal oxide semiconductor layer includes a titanium oxide binder together with metal oxide spherical particles. The metal oxide semiconductor layer is 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. The photoelectric cell according to claim 3, wherein:   The photoelectricity according to any one of claims 1 to 10, wherein 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 nm. cell.   12. The photoelectric cell according to claim 1, wherein the insulating substrate is a transparent glass substrate.

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