JP5914139B2 - Method and apparatus for manufacturing porous semiconductor electrode - Google Patents

Description

The present invention is a method and apparatus for manufacturing a multi-porous semiconductor electrodes that form a thin film on the porous metal surface of the substrate having pores penetrating the front and back, for example, photoelectric dye-sensitized The present invention relates to the manufacture of chemical cells, photocatalytic films, and the like.

Conventionally, the use of solar cells or photovoltaic power generation systems has been promoted as part of the use of natural energy. In a solar battery system, a solar battery cell (photoelectrochemical cell) is used to convert sunlight into electric energy.
Research and development of the photoelectrochemical cell has been promoted for improving the photoelectric conversion efficiency, and in recent years, dye-sensitized photoelectrochemical cells have been known (see Patent Document 1 and Patent Document 2).

9, a dye-sensitized photoelectrochemical cell 90 of Patent Document 1 has a light-receiving side electrode 93 in which a thin film 92 made of a porous semiconductor with a dye is formed on the surface of a substrate 91 made of a porous metal. On the back surface of the light-receiving side electrode 93, a counter electrode 95 is installed in parallel at a predetermined interval via a spacer 94. The space between the spacers 94 is filled with an electrolyte 96 and the outer periphery thereof is covered with a transparent light transmissive film 97.
In such a dye-sensitized photoelectrochemical cell 90, an electromotive force is generated between the light receiving side electrode 93 and the counter electrode 95 facing each other with the electrolyte 96 interposed therebetween by the light received by the light receiving side electrode 93. The electromotive force can be taken out by a conductive wire 98 connected to the electrodes 93 and 95.

Here, in the conventional photoelectrochemical cell, the structure which formed the transparent electrode film made from a metal oxide on the surface of the electrode substrate by conductive glass etc. was used as the light-receiving side electrode 93.
On the other hand, in the dye-sensitized photoelectrochemical cell 90 of Patent Document 1, a thin film made of a porous semiconductor with a dye is formed on the surface of a porous metal substrate to receive a light-receiving side electrode made of porous semiconductor. 93 is formed.
In such a light-receiving side electrode of Patent Document 1, as compared with a conventional electrode using a glass substrate and a transparent electrode film, the manufacturing cost as a photoelectrochemical cell is reduced, the electrical resistance is reduced, the weight is reduced, and the flexibility is increased. Can be secured.

In the dye-sensitized photoelectrochemical cell 90 of Patent Document 1, when the light-receiving side electrode 93 is manufactured, in order to form a porous semiconductor thin film 92 with a dye on the surface of the porous metal substrate 91, A porous semiconductor to be the thin film 92 is applied in the form of a slurry to the surface of the substrate 91.
In FIG. 8, the light-receiving side electrode 93 is configured by applying a porous semiconductor thin film 92 on the surface of a porous metal substrate 91.
The substrate 91 is a porous conductive self-supporting substrate obtained by forming metal particles 91A into a plate shape by sintering or the like. A gap is formed between the particles 91A, and part of the substrate 91 penetrates the front and back of the substrate 91. The pores are 91B.
The thin film 92 is formed into a thin film by applying a porous semiconductor having a pigment to the substrate 91. Specifically, a porous semiconductor thin film is formed by applying slurry-like porous semiconductor particles (for example, a solution or paste containing a precursor of a porous semiconductor) to the surface of a porous metal substrate and then heating it. Then, the above-described thin film 92 is formed by adding a dye to the porous semiconductor thin film.

As described above, in Patent Document 1, a slurry of porous semiconductor particles to be the thin film 92 is applied to a porous metal substrate 91 in manufacturing the light-receiving side electrode 93.
Here, when the slurry of the porous semiconductor particles is applied to the substrate 91, the slurry of the porous semiconductor particles may spread on the surface of the substrate 91, and a part of the slurry particles 92A may be porous. May penetrate into the pores 91B.
In Patent Document 1, when a slurry of porous semiconductor particles (the above-described solution or paste) is applied to the surface of the substrate 91, it is spread or formed during the application of the slurry of porous semiconductor particles. It has been shown that the viscosity of a solution or paste is adjusted in order to adjust the film thickness, the degree of penetration into pores, and the like.

In the dye-sensitized photoelectrochemical cell 90 of Patent Document 1 described above, porous semiconductor particles to be the thin film 92 are applied in a slurry form to the substrate 91.
On the other hand, Patent Document 2 describes a method in which a slurry is not used when forming a thin film on a substrate.
Patent Document 2 discloses a cold spray method in which powdered titanium dioxide particles are sprayed onto a substrate with a pressurized gas in order to form a titanium dioxide catalyst film on a substrate, and the particles are deposited on the substrate surface. ing. In such a cold spray method, titanium dioxide particles that form a thin film are sprayed in a dry powder state, so that it is not necessary to use a slurry (including a liquid component).

JP 2010-21091 A JP 2008-297184 A

  By the way, in the light-receiving side electrode 93 in the dye-sensitized photoelectrochemical cell 90 of Patent Document 1 described above, the particles 92A enter the pores 91B of the porous metal substrate 91, whereby the porous semiconductor thin film 92 is obtained. Will vary in thickness. That is, the thickness of the thin film 92 is larger in the portion where the pore 91B is present than in the other portion by the amount of the particle 92A entering the pore 91B. When the thickness of the thin film 92 varies as described above, it is difficult for electrons to be diffused particularly in a thick portion, and the photoelectric conversion efficiency may be lowered.

  In order to avoid such penetration into the pores 91B, it is conceivable to increase the viscosity of the slurry of porous semiconductor particles applied to form the thin film 92. As a method other than the viscosity adjustment, it is conceivable to apply a slurry of porous semiconductor particles from the lower surface side of the substrate 91 made of porous metal. Therefore, it is inevitable that the slurry enters the pores 91B, and it can be said that the viscosity adjustment is the most realistic countermeasure.

However, when the viscosity of the slurry is increased in order to avoid the penetration into the pores 91B, not only the penetration into the pores 91B is suppressed, but also the diffusibility on the surface of the substrate 91 is lowered, and the coating is applied as a whole. The film may be thick, and there is a problem that it is difficult to adjust the viscosity so that these performances are comprehensively satisfied.
Further, it is difficult to keep the viscosity of the slurry of the porous semiconductor particles constant at the time of application, and it is difficult to avoid the entry of the slurry into the pores 91B, and the thickness of the thin film 92 may fluctuate.
Furthermore, in order to increase the viscosity, a high-boiling polymer compound may be added to the slurry. In such a case, the polymer compound is formed on the surface of the porous semiconductor after forming the porous semiconductor thin film. It is considered that the carbon residue such as the residue thereof or a decomposition product thereof may adhere, and, for example, may cause a decrease in performance when a dye-sensitized solar cell is obtained.

On the other hand, if the cold spray method as described in Patent Document 2 is used for forming a thin film on the substrate of the dye-sensitized solar cell, it is not necessary to form particles as a thin film into a slurry and apply it to the substrate surface. Intrusion into the pores of the slurry may be avoided.
However, based on the cold spray method, when the process of spraying the porous semiconductor particles onto the substrate with pressurized gas is experimentally performed, the penetration of the porous semiconductor particles into the substrate pores can be suppressed as expected, There was a problem that the substrate which received the spray was often damaged.

An object of the present invention is to provide a method and apparatus for manufacturing a porous semiconductor electrodes to the porous semiconductor thin film having a constant thickness is obtained.

As a result of earnest research, the inventors of the present invention have found that when the cold spray method is used, the pressurized gas wraps around the back surface through the pores of the substrate and floats the substrate, causing damage. It finds and proposes a unique configuration to solve this.
As shown in FIG. 7, a substrate 81 is held on the surface (mounting surface) of a mounting table 87 of an apparatus for cold spraying, and porous semiconductor particles and pressurized gas are applied to the surface of the substrate 81 using a spray device 88. Is sprayed.
By this spraying, a porous semiconductor thin film 82 is formed on the surface of the substrate 81. The porous semiconductor particles forming the thin film 82 are deposited on the substrate 81 in the form of powder rather than as a slurry, and the penetration of the substrate 81 into the pores 81B is suppressed.

Part of the pressurized gas sprayed with the porous semiconductor particles passes from the front surface side of the substrate 81 to the back surface side through the pores 81B of the substrate 81, and the back surface of the substrate 81 and the mounting surface (the surface of the mounting table 87). The cavity 86 is formed between the back surface of the substrate 81 and the mounting surface due to the gas accumulation.
Due to the formation of such a cavity 86, the substrate 81 is lifted from the mounting surface and deformed, and depending on the conditions, the substrate 81 vibrates like a film, and as a result, the substrate 81 is considered to be broken.
The present invention employs the following configuration in order to eliminate the cavity 86 caused by the pressurized gas that causes such destruction.

The method for producing a porous semiconductor electrode of the present invention is a method for producing a porous semiconductor electrode formed by forming a porous semiconductor thin film on the surface of a porous metal substrate having pores penetrating the front and back surfaces. there are a mounting surface for mounting the substrate, is formed on the mounting surface it has a gas capable of discharging to the outside degassing recess facing said mounting surface, said venting recess is The mounting surface is a plurality of grooves formed on the mounting surface, the substrate is mounted on the mounting surface, and the back surface of the substrate and the mounting surface are brought into close contact with each other. The porous semiconductor particles to be the thin film are sprayed with a pressurized gas on the surface of the substrate placed on the substrate, and the pressurized gas that has escaped to the back side through the pores of the substrate is discharged by the degassing recess. It is characterized by that.

In the present invention, by spraying the powdered porous semiconductor particles together with the pressurized gas on the surface of the substrate placed on the placing surface, and depositing the porous semiconductor particles thinly on the surface of the substrate, A substrate having a porous semiconductor thin film formed on the surface can be obtained.
At this time, among the porous semiconductor particles and the pressurized gas sprayed on the substrate, the porous semiconductor particles are deposited on the substrate surface as a thin film, but the pressurized gas is partially diffused around the substrate, The other part escapes to the back side of the substrate through the pores of the substrate.
Here, a concave portion for venting gas is formed on the mounting surface, and the pressurized gas that has escaped to the back side of the substrate through the pores is discharged by the concave portion for venting gas, and between the substrate and the mounting surface. There is no formation of cavities.
Therefore, the substrate placed on the placement surface can be taken out in a state in which a porous semiconductor thin film is formed on the surface without being destroyed.

Further, in the present invention, the venting recess is Ru are a number of groove line formed on the mounting surface.
In Rukoto using such a large number of groove line, wrapped around it pressurized gas to the back surface of the substrate, along the mounting surface by the grooves, the substrate mounting surface is adhesion area placement of surface It is discharged to the area without the substrate. For this reason, a cavity does not arise between a board | substrate and a mounting surface.

In the present invention, the concave portion for venting has sufficient exhaust capacity so as not to cause a cavity between the substrate and the mounting surface in consideration of the flow of pressurized gas to be sprayed and the penetration amount from the pores of the substrate. May be set as appropriate to obtain the above.
In addition, when spraying powdered porous semiconductor particles with a pressurized gas, the pressure, flow rate, temperature, etc. of the pressurized gas are the strength of the substrate, the amount of porous semiconductor particles to be a thin film, the thickness of the thin film, etc. What is necessary is just to set suitably according to.

The porous semiconductor electrode manufacturing apparatus of the present invention is a porous semiconductor electrode manufacturing apparatus configured by forming a porous semiconductor thin film on the surface of a porous metal substrate having pores penetrating the front and back surfaces. there are a mounting surface for mounting the substrate, is formed on the mounting surface it has a gas capable of discharging to the outside degassing recess facing said mounting surface, said venting recess is A mounting table that is a plurality of grooves formed on the mounting surface, and a spray device that sprays the porous semiconductor particles to be the thin film on the surface of the substrate mounted on the mounting surface with a pressurized gas It is characterized by having.
In the present invention, a porous semiconductor thin film is formed on the surface of a porous metal substrate having pores penetrating the front and back, based on the method for producing a porous semiconductor electrode of the present invention described above. Can do.

The schematic diagram which shows the manufacturing apparatus of the porous semiconductor electrode of the reference example used as the premise of embodiment of this invention. The schematic diagram which shows the mounting surface material of the said reference example . The schematic diagram which shows the spray operation | movement in the said reference example . The schematic diagram which shows the porous semiconductor electrode manufactured by the said reference example . Schematic diagram showing an apparatus for manufacturing a porous semiconductor electrode implementation of the invention. Schematic view showing the mounting surface material before you facilities embodiment. The schematic diagram for demonstrating the subject which this invention solves. The schematic diagram which shows the conventional dye-sensitized photoelectrochemical cell. The schematic diagram which shows the conventional porous semiconductor electrode.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[ Reference example ]
1 to 4 show a reference example which is a premise of the embodiment of the present invention.
4, in this reference example , a porous metal substrate made of a titanium sintered body is used as the substrate 11, a titanium dioxide porous semiconductor thin film is formed as the thin film 12 on the surface, and the thin film 12 is provided on the surface of the substrate 11. The porous semiconductor electrode 13 is manufactured.
Therefore, in this reference example , as shown in FIG. 1, a manufacturing apparatus 20 for forming a thin film 12 on the surface of the substrate 11 by a cold spray method is used to add powdered porous semiconductor particles 12A to be the thin film 12. Spray onto the surface of the substrate 11 with the pressurized gas G.

The manufacturing apparatus 20 has a mounting table 21 fixed on a foundation. On the upper surface side of the mounting table 21, a mounting surface material 22 on which the substrate 11 is mounted is supported horizontally.
The surface of the mounting surface material 22 is a mounting surface 23, and the back surface of the substrate 11 mounted on the mounting surface 23 is in close contact with the mounting surface 23.
As shown in FIG. 2, the mounting surface material 22 of the present reference example has a large number of through holes that penetrate from the surface that is the mounting surface 23 to the back surface of the mounting surface material 22 as the gas vent recesses of the mounting surface 23. A hole 26 is provided. Each of the through holes 26 has a circular cross section with a predetermined inner diameter, and the same object is two-dimensionally arranged on the mounting surface 23.

The cross-section of the through hole 26 is not particularly limited, such as a rectangle, an ellipse, or a honeycomb structure. The cross-sectional dimensions of the through holes 26 do not have to be the same, and through holes having different dimensions may be arranged. Further, the through hole 26 may be a through hole having a different cross-sectional shape.
Returning to FIG. 1, a clamp 24 for holding the edge of the substrate 11 placed on the placement surface 23 is installed on the outer peripheral portion of the placement surface 23.

A spray device 25 that can move along the placement surface 23 is installed above the placement surface 23.
The spray device 25 includes an external pressurized gas source (not shown) that supplies the pressurized gas G and a quantitative supply device (not shown) that supplies porous semiconductor particles.
In such a spray device 25, the porous semiconductor particles 12 </ b> A are dispersed by the pressurized gas G, ejected from the nozzle 25 </ b> B, and sprayed toward the surface of the substrate 11 placed on the placement surface 23. The thin film 12 can be formed on the surface of the substrate 11.
In addition, the quantitative supply device may be anything that can stably supply the necessary amount of porous semiconductor particles, such as a screw type, a coil type, a vibration type, a circle type, a table type, a wire net type, a saddle type, and a combination thereof. There are no particular restrictions such as positive displacement or loss-in-eight.

In this reference example , the porous semiconductor electrode 13 is manufactured by the following procedure.
As shown in FIG. 3, the board | substrate 11 is mounted in the mounting surface 23, and it fixes with the clamp 24 (refer FIG. 1). Subsequently, spraying is performed by the spray device 25, and the pressurized gas G in which the powdery porous semiconductor particles 12 </ b> A are dispersed is sprayed on the surface of the substrate 11.
By this spraying, porous semiconductor particles 12A are deposited on the surface of the substrate 11 to form the thin film 12.

  At this time, among the porous semiconductor particles 12A and the pressurized gas G sprayed on the substrate 11, the porous semiconductor particles 12A are deposited on the surface of the substrate 11 as the thin film 12, but the pressurized gas G is partially While diffusing around the substrate 11, another part passes through the pores 11 </ b> B of the substrate 11 to the back side of the substrate. A through hole 26 is formed in the mounting surface 23 as a degassing recess, and the pressurized gas G that has escaped to the back surface side of the substrate 11 through the pores 11 </ b> B passes through the through hole 26. It is discharged to the back surface side, and the cavity 86 (see FIG. 7) is not generated between the substrate 11 and the placement surface 23.

Accordingly, the porous semiconductor in which the powdery porous semiconductor particles 12A are thinly deposited on the surface of the substrate 11 placed on the placement surface 23, and the thin film 12 made of porous semiconductor is formed on the surface of the substrate 11. The electrode 13 can be manufactured.
And since the through-hole 26 as a degassing recessed part is formed in the mounting surface 23, destruction of the board | substrate 11 by the pressurized gas G used for spraying can be prevented beforehand, and it manufactures in this reference example. The porous semiconductor electrode 13 can be obtained reliably.

As shown in FIG. 4, the porous semiconductor electrode 13 manufactured in this way in this reference example has a large number of pores 11 </ b> B between the metal material particles 11 </ b> A constituting the substrate 11. However, by spraying the powdery porous semiconductor particles 12A by the cold spray method, the porous semiconductor particles 12A can be thinly deposited on the surface of the substrate 11, and the porous semiconductor particles 12A enter the pores 11B. There is nothing.
For this reason, the thin film 12 of the porous semiconductor particle 12A of titanium dioxide can obtain a stable film thickness at the thickness T.
Moreover, since it is a cold spray method, heating drying like slurry application is unnecessary, and it can manufacture efficiently in a short time.

[Implementation Embodiment
5 and 6, there is shown implementation of the invention.
As shown in FIG. 5, this embodiment, as in the reference example, which forms a thin film 12 on the surface of the substrate 11 to produce a porous semiconductor electrode 13, the reference example and similar cold spray A manufacturing apparatus 20A based on the law is used.

In the manufacturing apparatus 20A, each component configuration is the same as that of the reference example, and the same configuration is denoted by the same reference numeral, and redundant description is omitted. However, the mounting surface material 22A of the present embodiment is configured differently from the reference example .
As shown in FIG. 6, the mounting surface material 22 </ b> A of the present embodiment includes a large number of grooves 27 arranged in parallel to the surface that is the mounting surface 23 as a degassing recess of the mounting surface 23. Yes. The grooves 27 each have a rectangular cross section having a predetermined depth and a groove width, and are arranged in parallel along one side of the mounting surface 23.
The cross-sectional shape of the groove 27 is not particularly limited, such as a circle or an ellipse. Moreover, the cross-sectional dimension of the groove 27 does not need to be the same, You may arrange | position the groove shape of a different dimension. Further, the grooves 27 may be grooves having different cross-sectional shapes.

Also in this embodiment, the porous semiconductor electrode 13 in which the thin film 12 is formed on the surface of the substrate 11 can be manufactured based on the cold spray method by the same procedure as the reference example described above.
At this time, in the mounting surface material 22A of the present embodiment, the groove 27 is used as the gas vent recess of the mounting surface 23, and the pressurized gas G contained in the spray is discharged by the groove 27.
As shown in FIG. 5, the pressurized gas G passes through the pores 11 </ b> B of the substrate 11 to the back surface, and enters the nearest groove 27. The pressurized gas G collected in the grooves 27 is dissipated into the atmosphere in the region of the mounting surface 23 where the substrate 11 is not mounted. A part of the pressurized gas G collected in the groove 27 may be discharged to the surface side of the substrate 11 through the pores 11B in a region where the substrate 11 is not sprayed.

As described above, also in the present embodiment, the powdery porous semiconductor particles 12A are thinly deposited on the surface of the substrate 11 placed on the placement surface 23, and the porous semiconductor thin film 12 is deposited on the surface of the substrate 11. The porous semiconductor electrode 13 in which is formed can be manufactured.
And since the groove | channel 27 as a degassing recessed part is formed in the mounting surface 23, destruction of the board | substrate 11 by the pressurized gas G used for spraying can be prevented beforehand, and it manufactures by this embodiment. The porous semiconductor electrode 13 can be obtained reliably.

[Modification]
The present invention is not limited to the above-described embodiments, and modifications and the like within a scope that can achieve the object of the present invention are included in the present invention.
For example, the pressurized gas G used in the cold spray method may generally use air, but nitrogen gas or other inert gas may be used.

In each of the above embodiments, a porous metal substrate made of a titanium sintered body is used as the substrate 11 and the titanium dioxide porous semiconductor thin film 12 is formed on the surface thereof. However, other materials may be used for the substrate 11 and the thin film 12. The material may be selected as appropriate.
Furthermore, the structure for supporting the mounting surface materials 22 and 22A in the mounting table 21 may be designed as appropriate, and the specific structure of the spray device 25 and the structure for moving the spray device 25 and the mounting table 21 relative to each other are also necessary. What is necessary is just to design suitably so that an appropriate function may be acquired.

Wherein the through-hole 26 used as a reference example the recess for venting, but before the you facilities form with the grooves 27 as recesses for venting, the further mounting surface material to a bottom surface of the groove line 27 in combination You may form the through-hole 26 which goes out to a back side.
Furthermore, the gas venting recesses of the above embodiment are those in which grooves 27 are formed vertically and horizontally so as to draw a lattice shape (the substrate 11 is supported by protrusions formed in the lattice cage). May be.
Further, in the implementation form, between the mounting surface 23 and the substrate 11, it may be inserted spacer. As the spacer, those having pores having the same structure as that of the metal mesh or the porous metal substrate 11 can be used.

DESCRIPTION OF SYMBOLS 11 ... Board | substrate 11A ... Titanium sintered compact particle 11B ... Fine pore 12 ... Thin film 12A ... Porous semiconductor particle 13 ... Porous semiconductor electrode 20, 20A ... Manufacturing apparatus 21 ... Mounting stand 22, 22A ... Mounting surface material 23 ... Mounting Placement surface 24 ... Clamp 25 ... Spray device 25B ... Nozzle 26 ... Through hole 27 which is a recess for gas venting ... Groove G which is a recess for gas venting ... Pressure gas

Claims (2)

A method for producing a porous semiconductor electrode configured by forming a porous semiconductor thin film on the surface of a porous metal substrate having pores penetrating the front and back,
A mounting surface for mounting the substrate, is formed on the mounting surface have a gas exhaust possible venting recess to the outside facing the mounting surface, said venting recess, the front, wherein Using a mounting table that is a large number of grooves formed on the mounting surface ,
The substrate is placed on the mounting surface, the back surface of the substrate and the mounting surface are brought into close contact with each other, and porous semiconductor particles to be the thin film are added to the surface of the substrate placed on the mounting surface. A method for producing a porous semiconductor electrode, characterized in that the pressurized gas sprayed by pressurized gas and discharged to the back side through the pores of the substrate is discharged by the recess for degassing. A porous semiconductor electrode manufacturing apparatus configured by forming a porous semiconductor thin film on the surface of a porous metal substrate having pores penetrating the front and back,
A mounting surface for mounting the substrate, is formed on the mounting surface have a gas exhaust possible venting recess to the outside facing the mounting surface, said venting recess, the front, wherein A mounting table which is a large number of grooves formed on the mounting surface ;
An apparatus for producing a porous semiconductor electrode, comprising: a spray device that sprays the porous semiconductor particles to be the thin film with a pressurized gas on the surface of the substrate placed on the placement surface.

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