JP2006114350A - Manufacturing method of photoelectric conversion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a photoelectric conversion device enhanced in a short circuit current value and conversion efficiency. <P>SOLUTION: In the manufacturing method of the photoelectric conversion device formed by successively stacking an n-type charge transport layer comprising an oxide semiconductor 11, a light absorbing layer 14, and a p-type charge transport layer 15 on a conductive transparent electrode formed on a transparent substrate, a process for forming the n-type charge transport layer comprising the oxide semiconductor 11 contains a process for setting an inorganic porous material, a process for imbedding the oxide semiconductor material in the inorganic porous material by using a solution deposition method, and a process for dissolving the inorganic porous material. The process for imbedding the oxide semiconductor material in the inorganic porous materia by using the solution deposition method is preferably conducted by applying potential. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a photoelectric conversion device.

In Patent Document 1 and Non-Patent Document 1,

(Hereinafter referred to as “Gratzel”) and others have reported that the performance equivalent to that of Si solar cells was obtained by improving the dye and the semiconductor electrode (Patent Document 1 and Non-Patent Document 1). Here, a ruthenium dye is used as the dye, and anatase type porous titanium oxide (TiO ₂ ) fine particles are used as the n-type charge transfer layer. In order for such a Gratzel type cell using fine particles for a semiconductor electrode to replace a silicon solar cell, higher energy conversion efficiency than before is required. Therefore, an attempt has been made not only to apply and sinter the fine particle dispersion as it is, but also to produce a new structure in which pores and oxide semiconductors are controlled on a nanoscale.

For example, in Patent Document 2, porous metal oxides are prepared by depositing metal oxide fine particles by a chemical solution deposition method using a porous material having a nanoscale (50 to 400 nm) pore size made of a composite organic material as a template, and then firing. It has been reported to produce a thin semiconductor film. Further, Non-Patent Document 2 reports a method of producing titania nanowires by putting titania sol into a template using an electrophoresis method and gelling.
US Pat. No. 5,350,644 Japanese Patent Application No. 2002-111305 “J. Am. Chem. Soc.” 115, p. 6382, 1993 “Nano Letter”, 7, p. 717, 2002

However, in order to further improve the conversion efficiency, there has been a demand for a method capable of speedily controlling oxide semiconductors and vacancies in a finer region (nanoscale) than the prior art.
The present invention has been made in view of such background art, and the short-circuit current value and the conversion efficiency using the oxide semiconductor layer in which the charge transfer efficiency of the n layer and the p layer is improved and the contact area is improved. The manufacturing method of the photoelectric conversion apparatus which improved is provided.

As a result of intensive studies, the present inventors have found a new method for manufacturing a photoelectric conversion device and have reached the present invention.
That is, the present invention is a method for manufacturing a photoelectric conversion device in which an n-type charge transport layer, a light absorption layer, and a p-type charge transport layer are sequentially laminated on a conductive transparent electrode formed on a transparent substrate. The step of forming the n-type charge transport layer includes the step of installing an inorganic porous material, the step of embedding an oxide semiconductor material in the inorganic porous material using a solution deposition method, and the dissolution of the inorganic porous material. It is a manufacturing method of the photoelectric conversion apparatus characterized by including a process.

The step of embedding the oxide semiconductor material in the inorganic porous material using a solution deposition method is preferably performed by applying a potential.
The pore size of the inorganic porous material is preferably 40 nm or less.

The oxide semiconductor material is preferably titanium oxide.
The inorganic porous material is preferably a structure mainly composed of silicon.
The inorganic porous material is preferably a structure mainly composed of aluminum.

  According to the present invention, the manufacturing cost is low, the flexibility is possible, and the advantages of being able to reduce the weight are maintained, and the charge transfer efficiency of the n layer and the p layer is improved more easily than the conventional example. An improved oxide semiconductor layer can be created, and as a result, a method for manufacturing a photoelectric conversion device with improved short-circuit current value and conversion efficiency can be provided.

Hereinafter, the present invention will be described in more detail.
The method for manufacturing a photoelectric conversion device according to the present invention includes a photoelectric conversion device in which an n-type charge transport layer, a light absorption layer, and a p-type charge transport layer are sequentially stacked on a conductive transparent electrode formed on a transparent substrate. The step of forming the n-type charge transport layer includes a step of installing an inorganic porous material, a step of embedding an oxide semiconductor material in the inorganic porous material using a solution deposition method, and an inorganic material. And a step of dissolving the porous material.

  As a manufacturing method of the oxide semiconductor of the n-type charge transport layer, the step of installing an inorganic porous material, the step of solution deposition and electrodeposition, the step of dissolving the inorganic porous material, and the manufactured oxide semiconductor It demonstrates in order of the process of using and assembling a photoelectric conversion apparatus.

(About the process of installing inorganic porous material)
As an inorganic porous material for manufacturing the oxide semiconductor of the present invention, alumina nanoholes obtained by anodizing aluminum, a mesoporous structure in which an alkoxide such as silica is made porous by a sol-gel method, aluminum and silicon are simultaneously sputtered. Silicon nanoholes produced by doing so are preferably used, but are not limited thereto. At this time, the pore size and interval of the inorganic porous material, and the total area of the walls around the pores are reflected in the amount of the dye adsorbed on the oxide semiconductor as they are, which is important. Therefore, the pore diameter is preferably 40 nm or less, and more preferably 10 nm or less.

Here, an example in which silicon nanoholes are installed as an inorganic porous material is shown.
A substrate in which a transparent conductive film was formed on glass was used.
FIG. 2 is a schematic diagram for explaining a production process of silicon nanoholes.
2A and 2B correspond to the process A and the process B, respectively. Reference numeral 21 is a substrate, 22 is aluminum, 23 is silicon, and 24 is a hole.

(Process A)
As shown in FIG. 3, a film having the above structure can be formed on a substrate by performing sputtering with an appropriate amount of a silicon wafer 33 placed on an aluminum target 32 placed on a backing plate 31. .
The film formation has been described by taking sputtering as an example, but any film forming method capable of forming a similar structure can be applied to a method for producing silicon nanoholes.

(Process B)
Crystalline columnar aluminum formed in an amorphous silicon member can be etched with phosphoric acid or sulfuric acid to remove only aluminum and form holes 24 without changing the shape of silicon. Is possible.

  The silicon nanohole is a structure including aluminum and silicon, the columnar member including aluminum is surrounded by a region including the silicon, and the structure includes It is desirable that the silicon is contained in a ratio of 20 atomic% to 70 atomic% with respect to the total amount of the aluminum and silicon.

  The ratio is the ratio of the silicon to the total amount of the aluminum and silicon constituting the structure, and is preferably 25 atomic% or more and 65 atomic% or less, more preferably 30 atomic% or more and 60 atomic% or less.

  The diameter of aluminum (the diameter when the planar shape is a circle) can be controlled mainly in accordance with the composition of the structure (that is, the ratio of the silicon), and the average diameter is 0.5 nm or more and 50 nm or less, Preferably they are 0.5 nm or more and 20 nm or less. The diameter of the aluminum is substantially equal to the diameter of the hole 24 in the filling material region.

The structure can be manufactured using a method of forming a film in a non-equilibrium state. As the film forming method, a sputtering method is preferable, but a film forming method for forming a substance in any non-equilibrium state such as resistance heating vapor deposition, electron beam vapor deposition (EB vapor deposition), or ion plating method can be applied. is there. When the sputtering method is used, magnetron sputtering, RF sputtering, ECR sputtering, or DC sputtering can be used. When the sputtering method is used, the film is formed in an argon gas atmosphere at a pressure in the reactor of about 0.2 to 1 Pa. At the time of sputtering, the aluminum and silicon may be separately prepared as target raw materials, but a target material in which aluminum and silicon are baked at a desired ratio in advance may be used.
The structure formed on the substrate is preferably formed at a substrate temperature of 20 ° C. or higher and 300 ° C. or lower, preferably 20 ° C. or higher and 200 ° C. or lower.

(Solution deposition method and electrodeposition process)
By immersing the substrate on which the inorganic porous material is placed in a chemical deposition solution, an oxide semiconductor such as titanium oxide or zinc oxide can be deposited in the pores. For example, when titanium oxide is precipitated, a salt that can be dissolved in a solvent such as titanyl sulfate or ammonium tetrafluorotitanate is used as a salt containing titanium. At this time, it is allowed to stand for several minutes to 24 hours in a solution adjusted to pH 1.5 to 4.0 with ammonium chloride or the like. The immersion time can be appropriately set depending on the pore diameter and the growth rate of the oxide semiconductor. Moreover, although it is preferable to use pure water as a solvent, it is not restricted to this.

The case where ammonium tetrafluorotitanate is used as the salt containing titanium will be described in more detail.
First, a substrate is prepared in which silicon nanoholes having a hole diameter of 10 nm are placed as inorganic porous materials on a substrate with electrodes. This substrate was immersed in a solution prepared by dissolving 0.1 to 0.3 mol / L ammonium tetrafluorotitanate and 0.1 to 0.3 mol / L boric acid and adjusting the pH to 3.5 to 4.0. To do. At this time, the temperature of the solution is from room temperature to 40 ° C., but is not limited to this temperature range. For example, in the case of a solution in which titanyl sulfate is adjusted to about pH 2, 50 to 70 ° C. is preferable, and optimum depending on the solute and pH. Temperature exists. However, generally from room temperature to 100 ° C. is preferable, and further from 30 ° C. to 70 ° C. is preferable for generating in the pores. By immersing in the prepared solution for 15 minutes to 2 hours, titanium oxide can be generated in the pores.

  In addition, applying a potential when performing this step is preferable as a method for improving the growth rate. More specifically, the generation rate is improved by immersing the inorganic porous material in the chemical deposition solution and applying a potential in this state to stack the fine particles present in the solution in the pores. The method for applying a potential in the present invention uses a three-electrode or two-electrode method. Here, the configuration of three electrodes is shown in FIG. Reference numeral 51 is a reference electrode, 52 is a counter electrode, 53 is a sample (working electrode), 54 is a beaker, 55 is an electrolytic solution, and 56 is a mantle heater.

  At this time, the applied potential is preferably −0.1 to −1000 V, more preferably −0.1 to −100 V. The pH of the chemical deposition solution is preferably lower than the isoelectric point of the oxide semiconductor. For example, since the isoelectric point of titanium oxide is pH 4-6, when the pH is 4 or less, the lamination of fine particles at the potential proceeds more smoothly.

(Process of dissolving inorganic porous material)
Metals, metal oxides, alloys using them, and the like exist as inorganic porous materials. It is necessary to appropriately determine an etching method in which only this inorganic porous material is dissolved and the oxide semiconductor filled in the holes is not dissolved. As an etching method, a method of dissolving the inorganic porous material by dipping in an acid or alkali solution is preferable, but the method is not limited thereto.

  Specifically, in the case of silicon nanoholes filled with titanium oxide in the holes, only the titanium oxide in the holes is placed on the substrate by immersing in a sodium hydroxide solution that dissolves only the silicon nanoholes for several minutes to one hour. Can be left. When alumina nanoholes are used as the inorganic porous material, for example, the alumina nanoholes are dissolved by immersing them in a 5 wt% phosphoric acid solution for about 30 minutes to 2 hours.

(Configuration of photoelectric conversion device and assembly process)
A structure of a photoelectric conversion device using the oxide semiconductor of the present invention is described.
First, a conventional Gratzel type photoelectric conversion device will be described.

FIG. 4 is a schematic cross-sectional view showing a schematic configuration of a conventional photochemical battery using a Gratzel type dye-sensitized semiconductor electrode.
In FIG. 4, 44 is a glass substrate, 45 is a transparent electrode formed on the surface, and 41 is an anatase-type TiO ₂ fine particle layer, which is made of a porous joined body in which titanium oxide fine particles are joined together. Further, 42 is a dye bonded to the surface of the titanium oxide fine particles and functions as a light absorption layer.

The operation principle of this Gratzel type cell will be described. Light is incident from the left side of FIG. Then, the electrons in the dye constituting the light absorption layer 42 are excited by incident light and move to the conduction band of titanium oxide. The dye that has lost electrons and is in an oxidized state quickly receives electrons from the p-type charge transport layer 43, for example, iodine ions of the electrolyte, and is reduced to return to the original state. Electrons injected into the anatase TiO ₂ fine particle layer 41 move between the titanium oxide fine particles by a mechanism such as hopping conduction and reach the anode 45. In addition, iodine ions that are in an oxidized state (I ₃ ⁻ ) by supplying electrons to the dye receive electrons from the cathode 46 and are reduced to return to the original state (I ⁻ ).

As can be inferred from the above operating principle, in order for the electrons and holes generated in the dye to be efficiently separated and moved, the energy level of the excited electron of the dye must be higher than the conduction band of TiO _2. The energy level of the hole must be lower than the redox level.

  In the dye-sensitized cells such as the above-described Gratzel-type cell, since the light absorption rate of the dye 1 layer is not sufficient, the surface area is increased to increase the substantial light absorption amount. The present invention is not limited to dye sensitization, and can be widely used for general photoelectric conversion devices having a configuration in which the surface area is increased because the light absorption rate is not sufficient. This method of enlarging the surface has a problem that the charge transfer is not sufficiently efficient although the method of dispersing and bonding the fine particles as in the Gratzel type cell is simple. For example, the p-type charge transport layer does not sufficiently permeate into the fine particle layer, so that the junction area is reduced, and since the pores of the fine particle layer are narrow, the diffusion of ions such as iodine becomes rate limiting, and the current is increased. There is a problem that electric charges cannot be transported sufficiently. Even when the p-type charge transport layer is solidified, it is difficult to sufficiently fill the space between the fine particles with the p-type charge transport layer.

  A schematic diagram of a photoelectric conversion device manufactured using the oxide semiconductor of the present invention is shown in FIG. The oxide semiconductor 11 of the present invention is preferably an n-type wide gap semiconductor. Specifically, titanium oxide, zinc oxide, tin oxide, or the like is preferably used.

  In the photoelectric conversion device according to the present invention, since the oxide semiconductor 11 is an n-type wide gap semiconductor, an electrolyte including a p-type wide gap semiconductor or a redox pair with a light absorption layer 14 such as a dye interposed therebetween, A p-type charge transport layer 15 such as a polymer conductor is required.

  In the photoelectric conversion device of the present invention, since the voids can be controlled by an inorganic porous material, it is convenient when filling an electrolyte functioning as the p-type charge transport layer 15 or a p-type semiconductor. That is, in the case of an electrolyte, the diffusion of iodine ions and the like is fast, and soaking is quick during the production. Also, when the p-type charge transporting layer is a solid such as CuI, it is convenient that the porous n-type layer can be filled quickly and the contact can be improved.

  In FIG. 1, the substrate is made of a substrate 12 made of glass, for example, sequentially provided with a conductive material 13 which is a transparent electrode, and an oxide semiconductor 11 as an n-type charge transport layer and a light absorption layer formed on the surface thereof. 14 and. The light absorption layer 14 is provided between the oxide semiconductor 11 and the p-type charge transport layer 15.

  The light irradiation surface is determined by the surface on which the transparent electrode is used. As shown in FIG. 1, either the n-type charge transport layer side or the p-type charge transport layer side may be configured as long as there is little absorption or reflection of irradiation light to the light absorption layer. Also, it can be used by light irradiation from both sides. These configurations depend on the manufacturing method and composition of the charge transport layer to be combined.

  Although not shown, an n-type charge transport thin film and a p-type charge transport thin film are provided between the conductive material 13 and the oxide semiconductor 11 or between the catalyst layer 18 and the p-type charge transport layer in order to prevent leakage. Is preferably installed as appropriate.

As the light absorption layer 14 of the photoelectric conversion device of the present invention, various semiconductors and pigments can be used. As the semiconductor, an amorphous semiconductor having a large i-type light absorption coefficient or a direct transition type semiconductor is preferable. As the dye, organic dyes such as metal complex dyes and / or polymethine dyes, perylene dyes, rose bengal, eosin Y, mercurochrome, Santalin dyes, cyanine dyes, and natural dyes are preferable. The dye preferably has a suitable linking group for the surface of the charge transfer layer. Preferred linking groups include COOH groups, cyano groups, PO ₃ H ₂ groups, or chelating groups having π conductivity such as oximes, dioximes, hydroxyquinolines, salicylates and α-ketoenolates. Among these, a COOH group and a PO ₃ H ₂ group are particularly preferable. When the dye used in the present invention is a metal complex dye, a ruthenium complex dye {Ru (dcbpy) ₂ (SCN) ₂ , (dcbpy = 2,2-bipyridine-4,4′-dicarcoxylic acid, etc.)} can be used. It is important that the oxidized / reduced substance is stable. The material of these light absorption layers is selected such that the electrochemical reaction of photoelectric conversion proceeds without delay.

  A redox system can be used for the p-type charge transport layer as well as a wet solar cell. Even when redox is used, not only a simple solution system but also a method of using carbon powder as a holding material or gelling an electrolyte. There is also a method using a molten salt or an ion conductive polymer. Furthermore, as a method for transporting electrons (holes), an electropolymerized organic polymer or a p-type semiconductor such as CuI, CuSCN, or NiO can be used. Since the transport layer needs to enter between the oxide semiconductors, an infiltration method that can be used for liquids or polymers, an electrodeposition method that can be used for a solid transport layer, a CVD method, or the like is suitable.

  A conductive material 17 is provided adjacent to the p-type charge transport layer 15. The conductive substance 17 may be provided on the entire outer surface of these layers or a part thereof. When the p-type charge transport layer is not solid, it is better to provide the conductive material 17 on the entire surface of the substrate 16 from the viewpoint of holding the charge transport layer. A catalyst layer 18 such as Pt or C is preferably provided on the surface of the conductive material 17 adjacent to the p-type charge transport layer 15 in order to efficiently reduce the redox couple, for example. The film thickness of the catalyst layer 18 may be such that light is not transmitted when light irradiation is performed only from the oxide semiconductor side in FIG. 1, but light irradiation is performed from the p-type charge transport layer side. It is preferable to set the film thickness according to the balance between the catalytic function and the transmitted light.

  Note that a substrate separate from the conductive material 17 may not be provided by causing the conductive material 17 described above to function as a base. In particular, when the p-type charge transport layer 15 is solid, it is preferable to directly place a conductive substance 17 such as Au or Ag on the top thereof.

  Although not shown, it is preferable from the viewpoint of improving the weather resistance that the wet type of the photoelectric conversion device of the present invention is sealed at least a portion other than the substrate. An adhesive or a resin can be used as the sealing material. Note that when the light incident side is sealed, the sealing material is preferably translucent.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited to these Examples.
Example 1
In this example, silicon nanoholes are formed on a conductive substrate, titanium oxide is deposited in the pores using a solution deposition method, and then a titanium oxide film in which silicon nanoholes are dissolved is used as an n-layer charge transport layer. It is an example regarding the manufacturing method of the photoelectric conversion apparatus.

First, conductive glass (F-doped SnO ₂ , 10Ω / cm ² ) was prepared as a substrate, and a 200 nm aluminum-silicon mixed film was formed on the ITO substrate.
FIG. 3 is a schematic view of the sputtering target used in the examples of the present invention.

  As shown in the figure, six 15 mm square silicon chips 33 are placed on a 101.6 mm (4 inch) aluminum target 32 on a backing plate 31. Sputtering was performed using an RF power source under the conditions of Ar flow rate: 50 sccm, discharge pressure: 0.7 Pa, and input power: 300 W. The substrate temperature was room temperature.

  The aluminum-silicon mixed film produced as described above was observed with a field emission scanning electron microscope (FE-SEM). It was confirmed that an aluminum-silicon structure thin film containing crystalline columnar aluminum having an interval surrounded by amorphous silicon of 10 nm, a diameter of 5 nm, and a height L of 1 μm was confirmed.

  The aluminum silicon mixed film thus produced was immersed in a 5 wt% phosphoric acid solution for 24 hours, and only aluminum columnar structure portions were selectively etched to form pores. As a result, a porous silicon oxide thin film composed of a member mainly composed of silicon oxide was produced.

  Next, the porous silicon oxide thin film etched with phosphoric acid (porous film composed of a member mainly composed of silicon oxide) was observed with an FE-SEM (field emission scanning electron microscope). The shape of the columnar hole viewed from the cross-sectional direction of the substrate was such that the pores surrounded by the silicon member penetrated almost vertically to the base substrate.

  Titanium oxide was produced from a titanyl sulfate aqueous solution using the silicon nanoholes thus produced. First, a 0.01 mol / L aqueous solution of titanyl sulfate was prepared using an aqueous HCl solution adjusted to pH 1. After stirring this solution for 1 hour, 2 mol / L urea was added and further stirred for 1 hour. Thereafter, the solution was held at 70 ° C. for 2 hours, and after confirming the precipitation of titanium oxide, the produced substrate with mold was immersed for 1 hour. Next, the substrate was taken out from the solution, and immersed in a 0.2 M aqueous sodium hydroxide solution for 30 minutes to dissolve the template, thereby producing titanium oxide grown from the substrate. As a result of observing the etched film with FE-SEM, it was confirmed that the film was a columnar film having an average diameter of about 5 nm reflecting the mold.

The dye used was Ru ((dcbpy) (COOH) ₂ ) ₂ (SCN) ₂ which is a Ru complex. The dye was dissolved in distilled ethanol, and the titanium oxide columnar membrane electrode was immersed in this for 24 hours to adsorb the dye to the electrode, and then taken out and dried at 80 ° C. Further, a counter electrode in which platinum was sputtered to a thickness of 10 nm on conductive glass (F-doped SnO ₂ , 10 Ω / cm ² ) was used, and I ⁻ / I ₃ ⁻ was used as the redox pair. The solute is tetrapropylammonium iodide (0.46 mol / L) and iodine (0.06 mol / L), and the solvent is a mixed solution of ethylene carbonate (80 vol%) and acetonitrile (20 vol%). Was used. This mixed solution was dropped on the titanium oxide columnar film and sandwiched between counter electrodes to form a cell.

For comparison, an n-type charge transport layer was prepared using titanium oxide fine particles having an average diameter of 20 nm, and a cell was similarly assembled using the n-type charge transport layer.
Then, a 500 W xenon lamp light equipped with an ultraviolet cut filter was irradiated from the n-type charge transport layer side. When this measurement result was compared with the titanium oxide fine particle film, the cell of the present invention had both a short circuit current value and a photoelectric conversion efficiency of about 10% larger. This is considered to be due to the fact that the charge transfer efficiency of the n layer and the p layer is improved and the contact area is improved.

Example 2
In this example, alumina nanoholes are formed on a conductive substrate, titanium oxide is deposited using a solution deposition method while applying a potential in the pores, and then the titanium oxide film in which the alumina nanoholes are dissolved is used as an n-layer charge. It is an example regarding the manufacturing method of the photoelectric conversion apparatus used as a transport layer.

First, conductive glass (F-doped SnO ₂ , 10Ω / cm ² ) was prepared as a substrate, and an Al film having a thickness of 2 μm was formed on the transparent conductive film. At this time, the gas was Ar, the gas pressure was 30 mTorr, and the DC power was 1000 W.

  The substrate was anodized using an anodizing apparatus. A 0.3M oxalic acid aqueous solution was used as the electrolyte, and the electrolyte was held at 17 ° C. by a constant temperature water bath. Here, the anodic oxidation voltage was DC 40 V, and the current value was displayed on the monitor, and it was confirmed that the current layer was penetrated into the underlayer when the current value became small.

After anodizing treatment, washing with pure and isopropyl alcohol was performed.
Then, the pore wide process immersed in 5 wt% phosphoric acid solution was performed for 40 minutes, and the wall 14 of the nanostructure was produced by performing surface polishing.

  The substrate was immersed in a solution in which 0.1 mol / L ammonium tetrafluorotitanate and 0.3 mol / L boric acid were dissolved and adjusted to pH 3.5 to 4.0, and a potential was applied. A potential of −1 V was applied at room temperature for 5 minutes in a three-electrode method using a silver-silver chloride electrode as a reference electrode, a platinum mesh electrode as a counter electrode, and a conductive substrate having alumina nanoholes as a working electrode. Thereafter, the alumina nanoholes are dissolved by immersing in 5 wt% phosphoric acid for 1 hour, washed with water and dried, and then heated to about 350 to 500 ° C. in a furnace to obtain a columnar film formed on the substrate. It was.

The dye used was Ru ((dcbpy) (COOH) ₂ ) ₂ (SCN) ₂ which is a Ru complex. The dye was dissolved in distilled ethanol, and the zinc oxide needle crystal electrode was immersed in this for 24 hours to adsorb the dye to the electrode, and then taken out and dried at 80 ° C. Further, a counter electrode in which platinum was sputtered to a thickness of 10 nm on conductive glass (F-doped SnO ₂ , 10 Ω / cm ² ) was used, and I ⁻ / I ₃ ⁻ was used as the redox pair. The solute is tetrapropylammonium iodide (0.46 mol / L) and iodine (0.06 mol / L), and the solvent is a mixed solution of ethylene carbonate (80 vol%) and acetonitrile (20 vol%). Was used. This mixed solution was dropped on the titanium oxide columnar film and sandwiched between counter electrodes to form a cell.

For comparison, an n-type charge transport layer was prepared using titanium oxide fine particles having an average diameter of 20 nm, and a cell was similarly assembled using the n-type charge transport layer.
Then, a 500 W xenon lamp light equipped with an ultraviolet cut filter was irradiated from the n-type charge transport layer side. When this measurement result was compared with the titanium oxide fine particle film, the cell of the present invention had both a short circuit current value and a photoelectric conversion efficiency of about 10% larger. This is considered to be due to the fact that the charge transfer efficiency of the n layer and the p layer is improved and the contact area is improved.

Example 3
In this example, silica nanoholes are formed on a conductive substrate, titanium oxide is deposited using a solution deposition method while applying a potential to the pores, and then the titanium oxide film in which the silica nanoholes are dissolved is used as an n-layer charge. It is an example regarding the manufacturing method of the photoelectric conversion apparatus used as a transport layer.

Nitrogen 0.7 mol, water 12 mol, ethanol 15 mol, n-hexadecyltrimethylammonium chloride 0.2 with respect to 1 mol of tetraethylorthosilicate (TEOS) as a raw material for preparing a reaction liquid for producing silica nanoholes Mole. This solution was added onto conductive glass (F-doped SnO ₂ , 10Ω / cm ² ) and spin-coated under the condition of 3000 rpm. Then, the silica nanohole was produced by performing heat processing at 400 degreeC in air | atmosphere.

  In this way, silica nanoholes were filled with titanium oxide in the same manner as in Example 1. Next, the substrate was taken out from the solution, and immersed in a 0.2 M aqueous sodium hydroxide solution for 30 minutes to dissolve the template, thereby producing titanium oxide grown from the substrate. As a result of observing the etched film with FE-SEM, it was confirmed that the film had a dendritic structure with an average pore diameter of about 5 nm reflecting the template.

The dye used was Ru ((dcbpy) (COOH) ₂ ) ₂ (SCN) ₂ which is a Ru complex. The dye was dissolved in distilled ethanol, and the zinc oxide needle crystal electrode was immersed in this for 24 hours to adsorb the dye to the electrode, and then taken out and dried at 80 ° C. Further, a counter electrode in which platinum was sputtered to a thickness of 10 nm on conductive glass (F-doped SnO ₂ , 10 Ω / cm ² ) was used, and I ⁻ / I ₃ ⁻ was used as the redox pair. The solute is tetrapropylammonium iodide (0.46 mol / L) and iodine (0.06 mol / L), and the solvent is a mixed solution of ethylene carbonate (80 vol%) and acetonitrile (20 vol%). Was used. This mixed solution was dropped on a titanium oxide dendritic membrane and sandwiched between counter electrodes to form a cell.

For comparison, an n-type charge transport layer was prepared using titanium oxide fine particles having an average diameter of 20 nm, and a cell was similarly assembled using the n-type charge transport layer.
Then, a 500 W xenon lamp light equipped with an ultraviolet cut filter was irradiated from the n-type charge transport layer side. When this measurement result was compared with the titanium oxide fine particle film, the cell of the present invention had both a short circuit current value and a photoelectric conversion efficiency of about 10% larger. This is considered to be due to the fact that the charge transfer efficiency of the n layer and the p layer is improved and the contact area is improved.

  The manufacturing method of the photoelectric conversion device of the present invention is low in manufacturing cost, can improve the charge transfer efficiency of the n layer and the p layer, and can create an oxide semiconductor layer having an improved contact area. Since a photoelectric conversion device with improved conversion efficiency can be provided, it can be used for photovoltaic elements, optical sensors, photodiodes, and the like.

It is a schematic diagram which shows the structure of the photoelectric conversion apparatus of this invention. It is a schematic diagram which shows the process of producing an inorganic porous material in the manufacture process of the photoelectric conversion apparatus of this invention. It is a schematic diagram which shows arrangement | positioning of the raw material which produces an inorganic porous material in the manufacture process of the photoelectric conversion apparatus of this invention. It is the schematic diagram which showed the structure of the conventional Gratzel cell. In the manufacturing process of the photoelectric conversion device of the present invention, it is a schematic view of a device for manufacturing an oxide semiconductor by applying a potential.

Explanation of symbols

11 Oxide Semiconductor 12 Substrate 13 Conductive Material (Anode)
14 light absorption layer 15 p-type charge transport layer 16 substrate 17 conductive material (cathode)
18 catalyst layer 21 substrate 22 aluminum 23 silicon 24 hole 31 backing plate 32 aluminum target 33 silicon wafer 41 anatase TiO ₂ fine particle layer 42 light absorption layer 43 p-type charge transport layer 44 glass 45 transparent electrode layer (anode)
46 Transparent electrode layer (cathode)
51 Reference electrode 52 Counter electrode 53 Sample (working electrode)
54 Beaker 55 Electrolyte 56 Mantle heater

Claims (6)

  A method of manufacturing a photoelectric conversion device in which an n-type charge transport layer, a light absorption layer, and a p-type charge transport layer are sequentially laminated on a conductive transparent electrode formed on a transparent substrate, the method comprising: The step of forming the charge transport layer includes a step of installing an inorganic porous material, a step of embedding an oxide semiconductor material in the inorganic porous material using a solution deposition method, and a step of dissolving the inorganic porous material. A method for manufacturing a photoelectric conversion device.   The method for manufacturing a photoelectric conversion device according to claim 1, wherein the step of embedding the oxide semiconductor material in the inorganic porous material using a solution deposition method is performed by applying a potential.   The method for manufacturing a photoelectric conversion device according to claim 1 or 2, wherein the pore size of the inorganic porous material is 40 nm or less.   The method for manufacturing a photoelectric conversion device according to claim 1, wherein the oxide semiconductor material is titanium oxide.   The method for manufacturing a photoelectric conversion device according to claim 1, wherein the inorganic porous material is a structure mainly composed of silicon.   The method for manufacturing a photoelectric conversion device according to any one of claims 1 to 4, wherein the inorganic porous material is a structure mainly composed of aluminum.

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