JP2010238507A - Electrode for dye-sensitized solar cell and dye-sensitized solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode capable of manufacturing a dye-sensitized solar cell excellent in a conversion efficiency and a dye-sensitized solar cell. <P>SOLUTION: The electrode for a dye-sensitized solar cell has a nonwoven cloth composed of a tin oxide containing fiber which is formed by using a spinnable sol solution containing a tin compound, and the porosity of the nonwoven cloth is 60-90%. Specifically, the tin oxide containing fiber composing the nonwoven cloth is preferred to be oriented in on direction. The dye-sensitized solar cell is provided with the above electrode. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a dye-sensitized solar cell electrode and a dye-sensitized solar cell.

Dye-sensitized solar cells have attracted attention in recent years because they can be produced at low cost without using silicon semiconductors. As shown in the schematic cross-sectional view of FIG. 1, this dye-sensitized solar cell has a positive electrode 11 having a transparent conductive film 11b and a platinum 11c in this order on a base material 11a, and a negative electrode having a transparent conductive film 10b on the base material 10a. 10, a porous titanium oxide particle layer 12 that adsorbs a pigment existing adjacent to the negative electrode 10, and an iodine solution as the electrolytic solution 13. When light is applied from the negative electrode side of such a dye-sensitized solar cell, the dye absorbs light and emits electrons, and the dye oxidizes iodine ions (3I ⁻ ) that are the electrolyte solution 13, thereby forming triiodine. It is referred to as a compound ion (I ₃ ⁻ ). The emitted electrons conduct through the porous titanium oxide particle layer 12 and reach the transparent conductive film 10b, and then reach the positive electrode 11 through an external circuit. Then, the electrons that have reached the positive electrode 11 reduce triiodide ions (I ₃ ⁻ ) to iodine ions (3I ⁻ ). Electricity can be generated by such a cycle.

  As an electrode of such a dye-sensitized solar cell, “a plastic film having a transparent conductive layer and a porous metal oxide layer laminated on the transparent conductive layer, and the porous metal oxide layer is electrospun. A dye-sensitized solar cell electrode characterized in that it is made of a metal oxide nonwoven fabric made of a fibrous metal oxide having an average fiber diameter of 50 to 1000 nm obtained by a method has been proposed (Patent Document 1). ). Such a metal oxide nonwoven fabric is obtained by collecting a solution comprising a mixture of a metal oxide precursor and a compound that forms a complex with the precursor, a solvent, and a high aspect-forming solute by an electrospinning method. It is disclosed that a metal oxide nonwoven fabric can be obtained by discharging and accumulating and firing on a substrate ", and in fact," titanium tetranormal butoxide (manufactured by Wako Pure Chemical Industries, Ltd., first grade) " To 1 part by weight, 1.3 parts by weight of acetic acid (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was added to obtain a uniform solution, and 1 part by weight of ion-exchanged water was added to this solution while stirring. The gel was dissociated by further stirring to prepare a transparent solution, and polyethylene glycol (Wako Pure Chemical Industries, Ltd. Preparation of a spinning solution by mixing 0.016 parts by weight of primary and average molecular weight 300,000 to 500,000), and using this spinning solution, accumulation and firing are performed by an electrospinning method to obtain a metal oxide nonwoven fabric made of titanium dioxide. It is disclosed that it was manufactured. However, since the metal oxide nonwoven fabric produced by such a method is formed using metal oxide particles, it has many grain boundaries, is not dense, has poor conductivity, and has poor current collection efficiency. Was low.

  As a method for producing a similar dye-sensitized metal oxide semiconductor electrode, “a method for producing a dye-sensitized metal oxide semiconductor electrode having a step of forming a titanium oxide semiconductor film on a transparent conductive film formed on a substrate” In forming the titanium oxide semiconductor film, the titanium oxide precursor-containing raw material liquid is sprayed toward the transparent conductive film by an electrospinning method, whereby the nanofibers containing the titanium oxide precursor on the transparent conductive film are formed. A method for producing a dye-sensitized metal oxide semiconductor electrode, characterized in that a deposited layer is formed and then the deposited layer is fired, is proposed. This “titanium oxide precursor-containing raw material liquid” is used as a titanium oxide precursor. It discloses that it is a solution containing 5 to 60% by weight of a body and 1 to 30% by weight of a polymer compound (Patent Document 2). In the examples, 0.5 g of polyvinyl acetate, 4.5 g of N, N-DMF, 2.0 g of titanium tetra-i-propoxide, and 0.5 g of acetic acid are used as the titanium oxide precursor-containing raw material liquid. It discloses that after forming a fiber deposition layer, it was fired at 500 ° C. for 1 hour. However, the nanofiber deposited layer manufactured by such a method has many grain boundaries, is not dense, is not conductive, has poor conductivity, and has low current collection efficiency as in Patent Document 1, resulting in low conversion efficiency. there were.

JP 2007-48659 A (Claim 1, Claim 2, Claim 4, Paragraph No. 0012, Paragraph Nos. 0081 to 0082, etc.) International Publication Number WO2006 / 041092 Pamphlet (Claims, Examples, etc.)

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an electrode that can produce a dye-sensitized solar cell with excellent conversion efficiency, and a dye-sensitized solar cell.

  The invention according to claim 1 of the present invention is an electrode for a dye-sensitized solar cell having a nonwoven fabric composed of tin oxide-containing fibers formed using a spinnable sol solution containing a tin compound, and the voids of the nonwoven fabric An electrode for a dye-sensitized solar cell, wherein the rate is 60 to 90%. "

  The invention according to claim 2 of the present invention is “the electrode for a dye-sensitized solar cell according to claim 1, wherein the tin oxide-containing fibers constituting the nonwoven fabric are oriented in one direction.” It is.

  The invention according to claim 3 of the present invention is “a dye-sensitized solar cell including the dye-sensitized solar cell electrode according to claim 1 or 2”.

  In the invention according to claim 1 of the present invention, tin oxide-containing fibers formed by using a spinnable sol solution containing a tin compound are dense fibers with few grain boundaries and high internal density. Dye-sensitized solar with a porosity of 60-90%, which has sufficient contact between tin oxide-containing fibers and can be sufficiently filled with titanium oxide particles. It is an electrode capable of producing a battery.

  In the invention according to claim 2 of the present invention, since the tin oxide-containing fibers are oriented in one direction, the electron extraction efficiency in the fiber orientation direction is high. It is an electrode which can manufacture a high dye-sensitized solar cell.

  The invention according to claim 3 of the present invention is a dye-sensitized solar cell with high conversion efficiency because it includes the dye-sensitized solar cell electrode.

Schematic cross-sectional view of a conventional dye-sensitized solar cell Schematic sectional view of the dye-sensitized solar cell of the present invention Typical sectional drawing of the manufacturing apparatus which can manufacture the nonwoven fabric of this invention The figure which shows the measuring method of the resistivity of the nonwoven fabric Plan view showing a state in which a silver paste is applied to a composite of a negative electrode and a porous titanium oxide particle layer

  The nonwoven fabric constituting the dye-sensitized solar cell electrode of the present invention (hereinafter sometimes simply referred to as “electrode”) is a tin oxide-containing fiber formed using a spinnable sol solution containing a tin compound. Become. Since spinning is performed using a spinnable sol solution, the reaction proceeds after spinning, a Sn-O-Sn network is formed, and fibers with fewer grain boundaries are obtained than those made from particles. In addition, because it is a dense fiber with high internal density, it has excellent conductivity.

  The tin oxide-containing fibers constituting the nonwoven fabric of the present invention are preferably bonded to each other. This is because electrons can be conducted not only through the length direction of the fibers but also through the adhesion points between the fibers, and further excellent in conductivity. This adhesion is preferably in a sintered state in which the adhesion is performed without using an adhesive so as to facilitate electrical conduction.

As a result, the nonwoven fabric preferably has a resistivity of 45 Ω · cm or less. More preferably, the resistivity is 30 Ω · cm or less. The smaller the resistivity, the better the conductivity, so the lower limit of the resistivity is not particularly limited. “Resistivity” means a value obtained by the following procedure.
(1) A 5 mm × 10 mm square sample S is collected from the nonwoven fabric, and the thickness (d: unit = μm) of the sample S is measured. In this measurement, an electron micrograph (magnification: 10,000 times) of the cross section of the sample S is taken, the thicknesses at five randomly selected points in the electron micrograph are measured, and the arithmetic average value is calculated as the thickness of the sample S. To do.
(2) After the sample S is placed on the glass plate G via the silver paste P, the sample S is dried at a temperature of 60 ° C. for 1 hour and adhered with the silver paste P. Note that the adhesion with the silver paste P is performed on a region 2.5 mm from each end in the longitudinal direction of the sample S, and the region of the sample S alone is a 5 mm × 5 mm square (see FIG. 4).
(3) After connecting a terminal to the silver paste P at both ends, the resistance value (R: unit = Ω) is measured with an ohmmeter.
(4) From this resistance value (R) and thickness (d), the resistivity (ρ: unit = Ω · cm) is calculated by the following equation.
ρ = R / (1 × 10 ⁴ / d)
(5) The resistivity is calculated for each of the three samples S, and the arithmetic average value is defined as “resistivity”.

  In addition, it is preferable that the average fiber diameter of the tin oxide containing fiber which comprises a nonwoven fabric is 1 micrometer or less. This is because such an average fiber diameter has a large surface area, increases the number of contact points with the porous titanium oxide particles, and is excellent in current collecting performance. The smaller the average fiber diameter, the more contact points with the porous titanium oxide particles and the higher the current collecting performance. Therefore, the average fiber diameter is more preferably 0.5 μm or less, and 0.4 μm or less. More preferably. On the other hand, the lower limit of the average fiber diameter is not particularly limited, but is preferably 50 nm or more so as to be excellent in the handleability of the nonwoven fabric. This "average fiber diameter" refers to the arithmetic average value of the fiber diameters at 40 points of the fiber. "Fiber diameter" is a value calculated based on this photograph taken by taking a micrograph of the nonwoven fabric surface magnified 1 to 50,000 times. When the fiber cross-sectional shape is not circular, the diameter of a circle having the same cross-sectional area is defined as the fiber diameter.

  Moreover, it is preferable that the aspect ratio of the tin oxide containing fiber which comprises a nonwoven fabric is 1000 or more. An aspect ratio of 1000 or more means that the fiber has a long fiber length. If the fiber has a long fiber length, it can conduct in the length direction of the fiber and has excellent current collecting performance. In other words, when the aspect ratio is small, electrons flow through the interface between fibers, the interface between fibers and particles, and / or the interface between particles, and these interfaces become resistance and increase internal resistance. This is because the conversion efficiency is lowered, but when the aspect ratio is 1000 or more, these interfaces are few and the resistance is small, and as a result, the conversion efficiency is easily increased. The higher the aspect ratio, the better the conductivity, so the upper limit of the aspect ratio is not particularly limited. Preferably, the fiber length is substantially continuous and the aspect ratio is infinite. The aspect ratio is a quotient obtained by dividing the average fiber length (unit: μm) by the average fiber diameter (unit: μm). This "average fiber length" refers to the arithmetic average value of the fiber lengths of 40 fibers, and "fiber length" is a value calculated based on this photograph taken by taking a micrograph of the nonwoven fabric surface magnified 500 to 50,000 times. Means.

  Since the nonwoven fabric of the present invention is formed using a spinnable sol solution containing a tin compound, the nonwoven fabric is composed of tin oxide-containing fibers. However, other substances can be included as long as the conductivity and transparency of the tin oxide-containing fiber are not impaired. For example, carbon nanotubes can be included. In the case of carbon nanotubes, it can be contained in an amount of 1 mass% or less.

The nonwoven fabric of the present invention has a porosity of 60 to 90%. When the porosity is less than 60%, there are few voids in which titanium oxide particles can exist, the amount of emitted electrons itself is reduced, and power generation efficiency tends to be lowered. Therefore, the preferred porosity is 65% or more. . On the other hand, when the porosity exceeds 90%, the voids increase, resulting in a decrease in the number of contacts between the tin oxide-containing fibers, and a decrease in conductivity through the contacts. The porosity is 85% or less. The porosity can be calculated from the following equation.
P = {1-W / (t × SG)} × 100
Here, P is the porosity (unit:%), W is the basis weight (unit: g ^{/ m} 2), t is the thickness (unit: μm), SG is the tin oxide-containing fiber density (unit: g / cm ³ In the case of 100% tin oxide, it represents 4.6 g / cm ³ ).

In addition, although the fabric weight of a nonwoven fabric is not specifically limited, It is preferable that it is 0.5-20 g / m < ² > from the point of handleability and productivity, and it is more preferable that it is 0.5-10 g / m < ² >. . Moreover, although thickness is not specifically limited, It is preferable that it is 1-100 micrometers, and it is still more preferable that it is 1-50 micrometers. This “weight” is a value calculated from the weight per 1 m ² of the nonwoven fabric, and the “thickness” is an electron micrograph (magnification: 10,000 times) of the cross section of the nonwoven fabric, which is randomly selected in the electron micrograph 5 The value obtained by measuring the thickness at a point and arithmetically averaging it.

  The nonwoven fabric of the present invention is composed of tin oxide-containing fibers formed using a spinnable sol solution containing a tin compound. Whether it is a “spinnable sol solution” can be determined by the following procedure. That is, a solution (solid content concentration: 20 to 50 wt%) for judging the spinnability is extruded from a metal nozzle (inner diameter: 0.4 mm) arranged in a horizontal direction against a grounded aluminum plate (extrusion amount: 0.5). -1.0 g / hr) and a voltage applied to the nozzle (electric field strength: 1 to 3 kV / cm, polarity: positive application or negative application) for 1 minute or more without causing solidification of the solution at the nozzle tip, Spinning continuously, fibers are accumulated on an aluminum plate to form a nonwoven fabric. Electron micrographs of the accumulated fibers are taken and observed, and there are conditions under which there can be produced a non-woven fabric having no droplets, an average fiber diameter of 40 fibers (arithmetic average value of 40 points) and an aspect ratio of 1000 or more. In some cases, the solution is judged to be “threadable”. On the other hand, if the conditions (that is, the solid content concentration, the extrusion amount, the electric field strength, and / or the polarity) are changed and they are combined in any way, when there are droplets, when the oil form is not a constant fiber form, the average When the fiber diameter exceeds 5 μm, or when the aspect ratio is less than 1000 (for example, in the form of particles) and there is no condition for producing a nonwoven fabric, the solution is judged to be “no spinnability”.

The spinnable sol solution containing such a tin compound has, for example, a general formula SnX _a · bH ₂ O (where X is a Cl atom, a Br atom, an I atom, an F atom, an OH group, a SO ₄ group, a NO ₃ group, or It can be prepared by dissolving a tin compound represented by CH ₃ COO group, wherein a represents an integer of 1 to 4 and b represents an integer of 0 to 6 in a solvent capable of dissolving the tin compound. More specifically, examples of tin compounds include SnCl ₂ , SnCl ₂ .2H ₂ O, SnBr ₂ , SnI ₂ , SnF ₂ , SnSO ₄ , Sn (CH ₃ COO) ₂ , Sn (NO ₃ ) _{2 and the} like. Among these, SnCl ₂ .2H ₂ O, SnCl ₂ , and SnBr ₂ can be preferably used from the viewpoint of reactivity and solubility. Incidentally, it is possible to use even those chemically modified with an organic compound such as _{Sn (CH 3) 2 Cl 2} .

Further, as the spinnable sol solution, for example, an alkoxide represented by the general formula Sn (OR) ₂ or Sn (OR) ₄ (R = methyl group, ethyl group, propyl group, butyl group, etc.) can be used. .

  The spinnable sol solution may contain a fluorine-based compound in order to improve conductivity. As this fluorine-based compound, those usually used as a dopant can be used, and for example, ammonium fluoride, hydrogen fluoride, and the like can be used.

  The solvent capable of dissolving the tin compound is not particularly limited as long as it can dissolve the tin compound, and alcohol can be used. More specifically, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, octyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, ethylene glycol, 1-methoxy-2-propyl alcohol, methoxyethoxyethanol, 2-phenyl Use ethyl alcohol, benzyl alcohol, allyl alcohol, 2-methyl-2-propen-1-ol, 3-methyl-3-buten-1-ol, phenol, methoxyphenol, ethoxyphenol, cresol, ethylphenol, etc. Can do.

  The viscosity of the spinnable sol solution is preferably 50 to 1000 cP (centipoise), and more preferably 70 to 700 cP (centipoise). This is because if the viscosity is less than 50 cP, there is a tendency not to be spinnable, and if the viscosity exceeds 1000 cP, the fiber diameter tends to increase. In order to make the spinnable sol solution have such a viscosity, the tin compound solution may be heated.

  If the sol solution is spinnable and does not adversely affect the conductivity of the nonwoven fabric, it can contain solids such as carbon nanotubes. In this case, it can be prepared by preparing a spinnable sol solution and then adding a solid.

  The nonwoven fabric of the present invention is formed using the spinnable sol solution. For example, it can be produced by collecting gel fibers spun by an electrostatic spinning method or a dry method without winding them. Among these, the electrospinning method is preferable because the average fiber diameter is 1 μm or less and / or the aspect ratio is 1000 or more (particularly continuous fiber).

  The electrospinning method that is suitable will be described. The spinnable sol solution is supplied to the spinning space, and the supplied spinnable sol solution is fiberized by applying an electric field to form a tin compound gel fiber. . More specifically, the spinnable sol solution is supplied to the spinning space by supply means such as a nozzle, a wire, and a brush. For example, when a nozzle is used, a tin compound gel-like fiber having an average fiber diameter of 1 μm or less can be easily produced by using a nozzle having an inner diameter of 0.1 to 3 mm. In addition, when a supply means is metal, it can be used as one electrode.

  The electric field applied to the spinnable sol solution varies depending on the fiber diameter of the tin compound gel fiber, the distance between the supply means and the support, the solvent of the spinnable sol solution, the viscosity of the spinnable sol solution, and the like. Therefore, although not particularly limited, it is preferably 0.5 to 5 kV / cm. If it exceeds 5 kV / cm, air breakdown tends to occur, and if it is less than 0.5 kV / cm, it is difficult to form a fiber shape. By applying an electric field in this way, an electrostatic charge is accumulated in the spinnable sol solution, which is electrically pulled by the electrode on the support side, and stretched to be fiberized. Since the fibers are electrically stretched, the speed of the fibers is accelerated and the diameter is reduced as the fibers approach the support. In addition, it is thought that it becomes thinner by evaporation of the solvent, the electrostatic density in the spinnable sol increases, and it is split by the electric repulsive force and further thinned.

  Such an electric field can be applied, for example, by providing a potential difference between the supply means (for example, a nozzle) and the support. For example, a potential difference can be provided by applying a voltage to the supply means and grounding the support, and conversely, a potential difference can be provided by applying a voltage to the support and grounding the supply means.

  Subsequently, the said tin compound gel-like fiber is integrated | stacked on a support body. At this time, it is preferable to heat the support at 300 to 750 ° C. (preferably 350 to 700 ° C., more preferably 400 to 650 ° C., still more preferably 450 to 600 ° C.). When the support is heated in this manner, not only the tin compound gel-like fibers are accumulated, but also the tin compound gel-like fibers can be fired, the crystallization of the tin oxide compound proceeds, and the tin-containing fibers adhere to each other ( Sintering) increases the conductivity. Also, organic components such as solvents are removed. Furthermore, the nonwoven fabric can be manufactured without suppressing the shrinkage of the fiber and causing cracks.

  When the support is heated in this manner, the support is not particularly limited as long as it can be used even if it is maintained at a temperature at which the tin compound gel fiber can be fired. Carbon rolls or conveyors can be used. In addition, when it is not conductive like ceramics, a conductive material such as metal is separately provided as an electrode. For example, the conductive material is installed on the side opposite to the supply means (for example, nozzle) side of the conveyor, in contact with or away from the conveyor. The support may be porous or non-porous. The temperature of the support can be set, for example, by setting a heater inside or outside the support and heating it. In addition, the heating and firing time of the tin compound gel fiber by the support is preferably 10 seconds or longer so that the crystallization of the tin compound gel fiber proceeds and the tin-containing fiber having excellent conductivity is obtained. When accumulating and firing the tin compound gel fibers at the same time, it is preferably performed in the presence of oxygen, particularly in an air atmosphere so that a tin oxide compound can be efficiently formed.

  As mentioned above, it is a manufacturing method in which compound gel-like fibers are accumulated and fired at the same time on the support, but tin oxide is also oxidized by a method in which tin compound gel-like fibers are accumulated on the support to form a fiber web and then fired. A nonwoven fabric composed of the contained fibers can be produced. The firing conditions in this case can be carried out under the same conditions as in the case of simultaneous firing described above.

  The non-woven fabric of the present invention has a porosity of 60 to 90%, so that it is easy to achieve such a porosity, even if the support is heated or not heated, the tin compound gel 200 m / min. It is preferable to move at the above speed. By moving the support at such a speed, the tin compound gel-like fibers are easily oriented in one direction, and are continuously adhered in the length direction of the fibers, resulting in an increase in the filling rate of the fibers, resulting in a void ratio. This is because it tends to be low. A more preferable support moving speed is 300 m / min. Thus, a more preferable support moving speed is 400 m / min. That's it. The upper limit of the moving speed of the support is not particularly limited, but is 1200 m / min. It is preferable that:

  The non-woven fabric produced in this way is suitable because the tin oxide-containing fibers are oriented in one direction, so that electrons easily flow in the fiber orientation direction and are excellent in conductivity and current collecting performance.

  In the present invention, “oriented in one direction” means that the standard deviation value of fiber orientation is 30 or less. The smaller the standard deviation value of this fiber orientation, the smaller the tin oxide-containing fibers are oriented in one direction, and the better the electrical conductivity and current collection performance, so the preferred standard deviation value of fiber orientation. Is 28 or less. In addition, the minimum of the standard deviation value of fiber orientation is 0 in which all the tin oxide-containing fibers are oriented in the same direction.

This “standard deviation value of fiber orientation” is the angle (measured in the same rotational direction) formed by the tin oxide-containing fiber and the straight line formed when a straight line is drawn on the electron micrograph of the nonwoven fabric surface. A standard deviation value of an angle obtained by measuring a point and obtaining the measurement result. In addition, it is preferable to use what was image | photographed by 1000 time as the electron micrograph of the nonwoven fabric surface. The straight line can be drawn in any direction and is not particularly limited. In addition, when the angle of 100 points cannot be ensured with one straight line, the angle is measured by drawing a straight line parallel to the first straight line. The standard deviation value of the angle is a value obtained from the following equation.
Standard deviation value = {(nΣA ² − (ΣA) ² ) / n (n−1)} ^1/2
Here, A means each angle (°), and n means 100, which is the number of measurement points.

In order to adjust the porosity of the nonwoven fabric to 60 to 90%, it is preferable to pressurize after accumulating the tin compound gel-like fibers and before heating and baking, during or after heating and baking. This is because the porosity can be controlled by increasing the fiber filling rate and reducing the porosity by pressurization. The pressurization is not particularly limited because it changes depending on the moving speed when the support is moved by a nonwoven fabric forming method, particularly by an electrostatic spinning method, but 1 g is used so that the porosity can be 90% or less. / Cm ² or more is preferable, 5 g / cm ² or more is more preferable, and 10 g / cm ² or more is still more preferable. On the other hand, as the porosity is not less than 60%, preferably at 50 g / cm ² or less. In addition, after accumulating a tin compound gel-like fiber and before heat-firing, or when pressurizing after heat-firing, it can also heat simultaneously. In this case, it is preferable to heat to 100 to 450 ° C.

  The nonwoven fabric of the present invention can be produced by the method as described above, but the tin oxide-containing fibers having an average fiber diameter of 1 μm or less are supplied with the supply amount of the spinnable sol solution by the supply means, the electric field strength, It can be obtained by adjusting the concentration and / or the viscosity of the sol solution.

  The manufacturing method of the nonwoven fabric of this invention is demonstrated easily based on FIG. 3 which is an example of typical sectional drawing of a manufacturing apparatus.

First, the metering pump or the like spinnable sol solution prepared as described above from the sol solution storage part 1, it is supplied to the nozzle group 2 ₁ to 2 _11, extruded from the nozzle groups 2 ₁ to 2 ₁₁ to the spinning space It is. On the other hand, since a voltage is applied to the metal supply pipe 3 that supplies the spinnable sol solution from the sol solution storage unit 1 to the nozzle groups 2 ₁ to 2 ₁₁ , and the support 4 is grounded, the spinnability is increased. An electric field acts on the sol solution, and the extruded spinnable sol solution becomes a fiber, becomes a tin compound gel fiber, and flies toward the support 4. The nozzle groups 2 _{1 to} 2 ₁₁ may be swung (in particular, swung in the width direction of the support 4) in order to improve the texture of the nonwoven fabric. The tin compound gel fibers reach the support 4 and accumulate to form a nonwoven fabric. However, since the support 4 is heated and maintained at 300 to 750 ° C. by the heater 5, the tin compound gel fibers are fired. And becomes tin oxide-containing fibers. That is, it becomes a nonwoven fabric made of tin oxide-containing fibers. In addition, the support body 4 is a conveyor, and by adjusting the surface speed thereof, the tin compound gel-like fibers are oriented in one direction, and are continuously adhered in the length direction of the fibers, whereby the porosity is low. A nonwoven fabric can be formed.

In the manufacturing apparatus of FIG. 3, the gas supply device 6 is located upstream of the nozzle groups 2 ₁ to 2 ₁₁ so that the uniform flight of the tin compound gel fibers is not disturbed by the air flow generated by the heated support 4. And a flow of gas (particularly air) from the nozzle groups 2 ₁ to 2 ₁₁ toward the support 4 is formed. At the same time, an exhaust device 7 is arranged downstream of the support 4 to exhaust the supplied gas. Further, in the manufacturing apparatus of FIG. 3, in order to further reduce the influence of the air flow generated by the heated support 4, the support 4 is arranged vertically, and the nozzle is perpendicular to the support 4. Groups 2 _{1 to} 2 ₁₁ are arranged. The same effect can be obtained if the nozzle groups 2 ₁ to 2 ₁₁ are not arranged above the gravity direction of the support 4. Further, in the manufacturing apparatus of FIG. 3, the nozzle groups 2 ₁ to 2 ₁₁ , the support 4 and the like are accommodated in the container 8 so that the solvent of the volatilized spinnable sol solution is not dispersed.

In addition to the nonwoven fabric as described above, the electrode of the present invention includes a transparent conductive film so that electrons can be collected and supplied to an external circuit, and the nonwoven fabric and the transparent conductive film are in contact with each other. preferable. This transparent conductive film is transparent so that light can be transmitted to the porous titanium oxide particle layer without blocking light, and the light transmittance in the visible light region (about 400 to 700 nm) is 80% or more. It is preferable that it is transparent to some extent. Moreover, it is preferable that the resistivity is as low as 1 × 10 ⁻³ Ω · cm or less so that electrons can be collected and supplied to an external circuit. Examples of such transparent conductive films include tin oxide (fluorine-doped tin oxide; FTO), indium oxide (indium oxide and tin; ITO), and zinc oxide (aluminum-doped zinc oxide; AZO, gallium-doped). And zinc oxide (GZO).

  The nonwoven fabric in the electrode of the present invention is preferably in contact with the transparent conductive film. However, when in contact with the nonwoven fabric, electrons collected in the nonwoven fabric can be quickly conducted to the transparent conductive film. This contact state may be in a state where the non-woven fabric and the transparent conductive film are adhered or in a state where they are not adhered, but from the viewpoint of conductivity, it is preferably in an adhered state. Even in this bonded state, the transparent conductive film and the non-woven fabric are not oxidized because blocking the light transmission or blocking the conductivity leads to a decrease in conversion efficiency. It is preferable that they are bonded by a compound or a photocatalytic action such as titanium oxide or other transparent conductive materials (such as zinc oxide). Such a bonded state is, for example, a sintered state. The sintering of the transparent conductive film and the nonwoven fabric is performed by applying an adhesive such as a sol solution containing a tin compound to the transparent conductive film and / or the nonwoven fabric, drying them in a laminated state, and subsequently adhesiveness. And by sintering to increase conductivity. This sintering can usually be performed by heat treatment. However, according to the method of exposing to low-temperature plasma in a high-frequency electric field as disclosed in Table 2003-031673, aggressive heat treatment is performed. Since it can sinter at low temperature without performing, it can sinter the transparent conductive film and nonwoven fabric on a low melting-point base material like a plastic base material.

  When a sol solution containing a tin compound is used for sintering, the sol solution is preferably a spinnable sol solution similar to that described above. This is because grain boundaries are hardly formed when sintered and are excellent in conductivity. Moreover, it is preferable that the solid content concentration of a sol solution is 0.5-10 mass%. This is because the transparent conductive film and the nonwoven fabric can be sintered, and the tin oxide-containing fibers constituting the nonwoven fabric can be sintered. If the concentration is less than 0.5 mass%, the sintering tends to be insufficient, and if it exceeds 10 mass%, cracking tends to occur due to shrinkage during sintering, and the conductivity tends to deteriorate. is there. Moreover, when sintering a transparent conductive film and a nonwoven fabric, it considers the heat-resistant temperature of a transparent conductive film, and sinters. For example, when the transparent conductive film is made of a fluorine-doped tin oxide film (FTO film), the sintering temperature is preferably 300 to 450 ° C.

  The electrode of the present invention preferably has a non-woven fabric and a transparent conductive film as described above, but can further have a substrate for supporting the transparent conductive film. Although this base material is not specifically limited, For example, it can comprise from transparent materials, such as glass and a plastic film.

  The dye-sensitized solar cell of the present invention (hereinafter sometimes simply referred to as “solar cell”) will be described with reference to FIG. 2 which is a schematic cross-sectional view. The solar cell of the present invention comprises a negative electrode 20 of the present invention comprising a positive electrode 21, a base material 20a, a transparent conductive film 20b and a nonwoven fabric 20c, a layer 22 of porous titanium oxide particles adsorbed with a pigment filled in the negative electrode nonwoven fabric 20c, And an electrolyte solution 23. In the solar cell of the present invention, the electrode of the present invention is the negative electrode 20, and the electrode of the present invention is provided with a nonwoven fabric 20 c, and a layer 22 filled with porous titanium oxide particles adsorbing a dye in the nonwoven fabric 20 c. Therefore, the dye absorbs light, and the emitted electrons are efficiently conducted from the porous titanium oxide particles to the tin oxide-containing fibers, and quickly reach the transparent conductive film 20b. Therefore, it is a solar cell with high conversion efficiency. That is, when the nonwoven fabric is not provided as in the conventional negative electrode, electrons are conducted through the porous titanium oxide particles, but the electron moving distance in the porous titanium oxide was said to be 10 to 15 μm, and thus can be taken out. Although the amount of electrons was small and conversion efficiency was poor, in the present invention, the porous titanium oxide particles can be in contact with the tin-containing fibers, so that the electrons travel through the porous titanium oxide particles. Since it is quickly collected by the nonwoven fabric 20c made of tin oxide-containing fibers, it is a solar cell with high conversion efficiency.

  The solar cell of the present invention can have the same configuration as the conventional solar cell except that the electrode of the present invention is used. For example, the positive electrode 21 is composed of an electrode having a transparent conductive film 21b such as indium tin oxide (ITO) and platinum 21c in this order on a base material 21a such as glass. This positive electrode is available because it is commercially available.

The layer 22 of porous titanium oxide particles adsorbing the pigment filled in the nonwoven fabric 20c of the negative electrode 20 is prepared, for example, by preparing a paste containing titanium oxide, applying this paste to the nonwoven fabric, and baking it, and then adsorbing the pigment Can be formed. Alternatively, it can also be formed by depositing titanium oxide particles on the surface of the nonwoven fabric by a liquid phase deposition method and then adsorbing a dye to the deposited titanium oxide particles. The liquid phase precipitation method is a thin film synthesis method using hydrolysis of a metal fluoro complex, and the reaction mechanism is as follows.
^{_{MF x (x-2n) -}} + nH 2 O = MO n + nF - + 2nH +
H ₃ BO ₃ + 4H ⁺ + 4F ⁻ = HBF ₄ + 3H ₂ O

Thus, in the liquid phase precipitation method, a metal oxide is precipitated in a solution by a hydrolysis reaction of a metal fluoro complex (MF _x ^{(x-2n) −} ), and boric acid (H that easily reacts with fluoride ions (H By adding ₃ BO ₃ ), a more stable hydrofluoric acid (HBF ₄ ) can be formed, and the metal oxide can be efficiently precipitated. As described above, since the metal oxide can be precipitated in the liquid, even in the case of a nonwoven fabric having a low porosity as in the present invention, titanium oxide particles can be precipitated and sufficiently filled in the voids of the nonwoven fabric. it can.

  Since the iodine solution as the electrolytic solution 23 is commercially available as a reagent, it can be obtained. A gap is formed between such a positive electrode 21 and the negative electrode 20 provided with the nonwoven fabric layer 20c filled with porous titanium oxide particles adsorbed with a dye, and an electrolyte solution 23 is poured into the gap. Thus, the solar cell of the present invention can be manufactured.

  Examples of the present invention will be described below, but the present invention is not limited to the following examples.

Example 1
(1) Production of nonwoven fabric;
(1) -1 preparation of spinnable sol;
10 g of first tin chloride (SnCl ₂ ) and 100 ml of methanol were added to a 100 ml reaction vessel, and dissolved by stirring. The opening of the reaction vessel was left in an oven set at a temperature of 40 ° C. for one day with the lid covered with a hole pierced for solvent evaporation. Thereafter, this solution was concentrated by an evaporator to obtain a spinnable sol solution (concentration: 47%) having a viscosity of 120 cP.

(1) -2 Production of nonwoven fabric;
2 ml of the prepared spinnable sol solution is put into a plastic syringe equipped with a metal nozzle (inner diameter: 0.4 mm), extruded from the metal nozzle at a rate of 0.3 g / hour of extrusion, and a voltage of 12 kV is applied to the metal nozzle. Then, they were accumulated on a metal drum (earth) 6 cm away from the tip of the metal nozzle to form a fiber web of tin compound gel fibers. When the fibers were accumulated, the drum was rotated at a high speed (drum surface speed: 750 m / min.).

Subsequently, this fiber web was put into an electric furnace and from room temperature to 10 ° C./min. The non-woven fabric (average fiber diameter: 0.1 μm, basis weight: 5.7 g) fired by maintaining the temperature at 450 ° C. at a rate of 450 ° C. and maintaining for 30 minutes at a temperature of 450 ° C. / M ² , thickness: 15 μm, porosity: 90%, apparent density: 0.38 g / cm ³ , resistivity: 25 Ω · cm). When this nonwoven fabric was observed with an electron microscope, it was composed of substantially continuous fibers having an aspect ratio of 1000 or more.

(2) Production of solar cell;
(2) -1 Production of negative electrode;
Prepare 15mm square fluorine-doped tin oxide film-covered glass (FTO glass, manufactured by Asahi Glass Fabrictech Co., Ltd., TCO glass, type DU A-110U80), and surface the transparent conductive film (fluorine-doped tin oxide film) with ethanol and acetone. After washing, the substrate was further washed by irradiating with ultraviolet rays for 5 minutes.

The spinnable sol solution prepared in (1) -1 was diluted to 1 wt% with 1-butanol. After applying this diluted solution to the fluorine-doped tin oxide film of FTO glass, the non-woven fabric (5 mm square) produced in the above (1) -2 and the tetrafluoroethylene resin sheet were placed in this order, and added at 10 g / cm ² . While pressing, it was heated at a temperature of 80 ° C. for 5 minutes to bond the nonwoven fabric and the FTO glass. After bonding, the temperature is lowered from room temperature to 20 ° C./min. The anode was heated to 450 ° C. at a rate of 450 ° C. and maintained at 450 ° C. for 30 minutes, and the nonwoven fabric was sintered with a transparent conductive film (fluorine-doped tin oxide film) of FTO glass and a tin oxide compound. did.

(2) -2 Composite of negative electrode and porous titanium oxide particles;
After masking the area where the non-woven fabric of the negative electrode does not exist, it is immersed in a mixed solution of (NH ₄ ) ₂ TiF ₆ -0.1M and H ₃ BO ₃ -0.2M to deposit titanium oxide particles on the surface of the non-woven fabric. It was. After drying at a temperature of 100 ° C. for 30 minutes, 1 ° C./min. The temperature was raised to a temperature of 450 ° C. at a rate of 450 ° C. and maintained at 450 ° C. for 30 minutes.

  Next, the negative electrode mixed with the porous titanium oxide particles was immersed in a dye solution prepared by dissolving the dye N719 (0.05984 g) in 50 ml of t-butanol and 50 ml of acetonitrile at room temperature for one day. After the dye was adsorbed on the substrate, it was washed with dehydrated acetonitrile to produce a negative electrode in which porous titanium oxide particles adsorbed with the dye were mixed in the nonwoven fabric.

(2) -3 Preparation of electrolyte solution;
In a light-shielding bottle, 3-methoxypropiononitrile (10 ml), LiI (0.13358 g), I ₂ (0.1269 g), 4TBP (4-tert-butylpyridine (0.67605 g)), DMPr2-I (1,2 -Dimethyl-3-n-propylimidazoliumiodide (1.3572 g) was added and dissolved by stirring to prepare an electrolytic solution.

(2) -4 Production of positive electrode;
A 15 mm square tin-doped indium oxide (ITO) film-coated Nesa glass (manufactured by Furuuchi Chemical Co., Ltd.) was prepared, and the ITO film surface was washed with ethanol and acetone, and then further washed by irradiating with ultraviolet rays for 5 minutes.

  Next, using a sputtering apparatus (JEOL JFC-1600), vapor deposition was performed twice for 2 minutes at a current of 40 mA (target value of platinum thickness: 60 nm), and platinum was deposited on the surface of the ITO film to produce a positive electrode. .

(2) -5 assembly of solar cell;
Silver paste P (manufactured by Fujikura Kasei, Dotite D-500) was applied to each of the negative electrode and positive electrode glass (FG) in an L shape, and terminals were taken (see FIG. 5, where C is a non-woven fabric).

  Next, using a spacer (manufactured by Tamapoly, HM-52, thickness: 30 μm), the negative electrode and the positive electrode are combined, the electrolytic solution prepared in (2) -3 is enclosed, fixed with a clip, and dye-sensitized. A solar cell was assembled.

(Example 2)
A non-woven fabric was produced by the following method, and a dye-sensitized solar cell was assembled in the same manner as in Example 1 except that the non-woven fabric was used.

(1) -2 Production of nonwoven fabric;
A fiber web produced in the same manner as in Example 1 was placed in an electric furnace and pressurized at 10 g / cm ² to 10 ° C./min. The non-woven fabric (average fiber diameter: 0.1 μm, basis weight: 12.2 g) sintered at a temperature of 450 ° C. and sintered for 30 minutes at a temperature of 450 ° C. / ^{m 2,} thickness: 14 [mu] m, porosity 77%, apparent density: 0.87 g / cm ^3, the resistivity: 25Ω · cm) were prepared. When this nonwoven fabric was observed with an electron microscope, it was composed of substantially continuous fibers having an aspect ratio of 1000 or more.

Example 3
A non-woven fabric was produced by the following method, and a dye-sensitized solar cell was assembled in the same manner as in Example 1 except that the non-woven fabric was used.

(1) -2 Production of nonwoven fabric;
A fiber web produced in the same manner as in Example 1 was placed in an electric furnace and pressurized at 20 g / cm ² to 10 ° C./min. The non-woven fabric (average fiber diameter: 0.1 μm, basis weight: 15.1 g) sintered at a temperature of 450 ° C. and sintered for 30 minutes at a temperature of 450 ° C. / M ² , thickness: 16 μm, porosity: 75%, apparent density: 0.94 g / cm ³ , resistivity: 25 Ω · cm). When this nonwoven fabric was observed with an electron microscope, it was composed of substantially continuous fibers having an aspect ratio of 1000 or more.

Example 4
A non-woven fabric was produced by the following method, and a dye-sensitized solar cell was assembled in the same manner as in Example 1 except that the non-woven fabric was used.

(1) -2 Production of nonwoven fabric;
2 ml of the spinnable sol solution prepared in the same manner as in Example 1 was put into a plastic syringe equipped with a metal nozzle (inner diameter: 0.4 mm) and extruded from the metal nozzle at a rate of 0.3 g / hour of extrusion. A voltage of 12 kV was applied to the nozzle, and it was accumulated on a metal drum (earth) 6 cm away from the tip of the metal nozzle to form a fiber web of tin compound gel fibers. When the fibers were accumulated, the drum was rotated at a high speed (drum surface speed: 1000 m / min.).

Next, this fiber web was put in an electric furnace and pressurized from 10 g / cm ² to 10 ° C./min. The non-woven fabric (average fiber diameter: 0.1 μm, basis weight: 21.3 g) sintered at a temperature of 450 ° C. and sintered for 30 minutes at a temperature of 450 ° C. / M ² , thickness: 14 μm, porosity: 60%, apparent density: 1.52 g / cm ³ , resistivity: 25 Ω · cm). When this nonwoven fabric was observed with an electron microscope, it was composed of substantially continuous fibers having an aspect ratio of 1000 or more.

(Comparative Example 1)
(Preparation of spinning solution)
2.875 g of polyvinyl acetate (PVAc) was added to 22.125 g of N, N-dimethylformamide (DMF) and dissolved, and a solution in which 5 g of titanium tetraisopropoxide (TTip) was mixed with 2.5 g of acetic acid was added. A spinning solution was obtained.

(Manufacture of non-woven fabric)
2 ml of the prepared spinning solution is put into a plastic syringe equipped with a metal nozzle (inner diameter: 0.4 mm), extruded from the metal nozzle at a rate of extrusion amount of 0.3 g / hour, and a voltage of 12 kV is applied to the metal nozzle. It accumulated on the metal drum (earth | ground) 6 cm away from the front-end | tip of a nozzle, and formed the fiber web of the PVAc / TTiP mixed fiber. When collecting the fibers, the drum was rotated at 0.5 m / min. Then, it heat-processed for 30 minutes at the temperature of 120 degreeC, the containing solvent was removed, and it was set as the nonwoven fabric.

(Preparation of negative electrode)
Prepare 15mm square fluorine-doped tin oxide film-covered glass (FTO glass, manufactured by Asahi Glass Fabrictech Co., Ltd., TCO glass, type DU A-110U80), and surface the transparent conductive film (fluorine-doped tin oxide film) with ethanol and acetone. After washing, the substrate was further washed by irradiating with ultraviolet rays for 5 minutes.

Next, after placing the non-woven fabric (5 mm square) and the tetrafluoroethylene resin sheet in order on the fluorine-doped tin oxide film of FTO glass, heating was performed at a temperature of 120 ° C. for 10 minutes under a pressure of 1 kg / cm ^2. Then, the nonwoven fabric and the FTO glass were bonded. After bonding, the temperature is increased from room temperature to 10 ° C./min. The temperature is raised to 450 ° C. at a rate of 450 ° C. and maintained at 450 ° C. for 30 minutes to remove impurities by baking, and the nonwoven fabric made of titanium oxide fibers is baked into a transparent conductive film (fluorine-doped tin oxide film) of FTO glass. A bonded negative electrode was prepared. The titanium oxide fiber is a substantially continuous porous fiber having an aspect ratio of 1000 or more, and the physical properties of the nonwoven fabric are an average fiber diameter of 0.1 μm, a basis weight of 14.0 g / m ² , and a thickness of 16 μm. The porosity was 75% and the apparent density was 0.88 g / cm ³ .

(Composite of negative electrode and porous titanium oxide particles)
After masking the negative electrode where the non-woven fabric is not present, the negative electrode is immersed in a mixed solution of (NH ₄ ) ₂ TiF ₆ -0.1M and H ₃ BO ₃ -0.2M to deposit titanium oxide particles on the non-woven fabric surface. I let you. After drying at a temperature of 100 ° C. for 30 minutes, 1 ° C./min. The temperature was raised to a temperature of 450 ° C. at a rate of 450 ° C. and maintained at 450 ° C. for 30 minutes.

  Next, the negative electrode mixed with the porous titanium oxide particles was immersed in a dye solution prepared by dissolving the dye N719 (0.05984 g) in 50 ml of t-butanol and 50 ml of acetonitrile at room temperature for one day. After the dye was adsorbed on the substrate, it was washed with dehydrated acetonitrile to produce a negative electrode in which porous titanium oxide particles adsorbed with the dye were mixed in the nonwoven fabric.

  Thereafter, dye-sensitized solar cells were prepared in the same manner as in (2) -3 (preparation of electrolytic solution), (2) -4 (preparation of positive electrode), and (2) -5 (assembly of solar cells) in Example 1. I assembled the battery.

(Comparative Example 2)
A non-woven fabric was produced by the following method, and a dye-sensitized solar cell was assembled in the same manner as in Example 1 except that the non-woven fabric was used.

(1) -2 Production of nonwoven fabric;
2 ml of the spinnable sol solution prepared in the same manner as in Example 1 was put into a plastic syringe equipped with a metal nozzle (inner diameter: 0.4 mm) and extruded from the metal nozzle at a rate of 0.3 g / hour of extrusion. A voltage of 12 kV was applied to the nozzle, and it was accumulated on a metal drum (earth) 6 cm away from the tip of the metal nozzle to form a fiber web of tin compound gel fibers. When collecting the fibers, the drum was set at 0.5 m / min. It was rotated with.

Subsequently, this fiber web was put into an electric furnace and from room temperature to 10 ° C./min. The non-woven fabric (average fiber diameter: 0.1 μm, basis weight: 3.4 g) fired by heating at 450 ° C. at a rate of 450 ° C. and maintained for 30 minutes at a temperature of 450 ° C. / M ² , thickness: 15 μm, porosity: 94%, apparent density: 0.23 g / cm ³ , resistivity: 25 Ω · cm). When this nonwoven fabric was observed with an electron microscope, it was composed of substantially continuous fibers having an aspect ratio of 1000 or more.

(Comparative Example 3)
A non-woven fabric was produced by the following method, and a dye-sensitized solar cell was assembled in the same manner as in Example 1 except that the non-woven fabric was used.

(1) -2 Production of nonwoven fabric;
2 ml of the spinnable sol solution prepared in the same manner as in Example 1 was put into a plastic syringe equipped with a metal nozzle (inner diameter: 0.4 mm) and extruded from the metal nozzle at a rate of 0.3 g / hour of extrusion. A voltage of 12 kV was applied to the nozzle, and it was accumulated on a metal drum (earth) 6 cm away from the tip of the metal nozzle to form a fiber web of tin compound gel fibers. When collecting the fibers, the drum was set at 1000 m / min. It was rotated with.

The fiber web was then placed in an electric furnace and pressurized from 20 g / cm ² to 10 ° C./min. The non-woven fabric (average fiber diameter: 0.1 μm, basis weight: 23.6 g) sintered at a temperature of 450 ° C. and sintered for 30 minutes at a temperature of 450 ° C. / M ² , thickness: 13 μm, porosity: 55%, apparent density: 1.82 g / cm ³ , resistivity: 25 Ω · cm). When this nonwoven fabric was observed with an electron microscope, it was composed of substantially continuous fibers having an aspect ratio of 1000 or more.

(Evaluation of solar cells)
(1) Light quantity calibration;
In advance, the amount of light of simulated sunlight (simulated sunlight irradiation device: manufactured by Celic, SXL-500V2 type) was calibrated.

  Subsequently, simulated sunlight was irradiated for 10 minutes, and the light source of the simulated sunlight irradiation apparatus was warmed up.

Next, simulated sunlight was irradiated to a photodiode (manufactured by Spectrometer Co., Ltd., silicon photodiode, BS-520), and the height of the sample stage was adjusted so that the output current value was 0.606 mA. Thus, it was assumed that AM1.5 (100 mW / cm ² ) sunlight could be irradiated to the sample.

(2) Measurement of conversion efficiency;
The conversion efficiency of each solar cell (electrode area: 0.25 cm ² ) was measured using a Keithley 2400 source meter. That is, the measurement of current-voltage characteristics was performed by changing the voltage in the range of −0.1 to +0.8 V, reading the voltage value and the current value, and estimating the conversion efficiency. The results are shown in Table 2. Table 1 summarizes the state of the spinning solution and the surface speed of the drum and the applied pressure that particularly affect the porosity in producing the nonwoven fabric.

  From the results shown in Tables 1 and 2, it was found that the conversion efficiency is increased by using a spinnable spinning solution and the non-woven fabric having a porosity of 60 to 90%.

  The electrode for dye-sensitized solar cells of the present invention can be used as a negative electrode for dye-sensitized solar cells.

DESCRIPTION OF SYMBOLS 1 Sol solution storage part 2 _1-2 2 ₁₁ nozzle group 3 Supply pipe 4 Support body 5 Heater 6 Gas supply apparatus 7 Exhaust apparatus 8 Container 10, 20 Negative electrode 10a, 20a Base material 10b, 20b Transparent conductive film 20c Nonwoven fabric 11, 21 Positive electrode 11a, 21a Base material 11b, 21b Transparent conductive film 11c, 21c Platinum 12, 22 Porous titanium oxide particle layer 13, 23 Electrolyte G Glass plate S Sample P Silver paste FG Glass C Nonwoven fabric

Claims (3)

A dye-sensitized solar cell electrode having a nonwoven fabric composed of tin oxide-containing fibers formed using a spinnable sol solution containing a tin compound, characterized in that the porosity of the nonwoven fabric is 60 to 90% An electrode for a dye-sensitized solar cell. The dye-sensitized solar cell electrode according to claim 1, wherein tin oxide-containing fibers constituting the nonwoven fabric are oriented in one direction. A dye-sensitized solar cell comprising the dye-sensitized solar cell electrode according to claim 1.

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