JP2011023173A - Dye-sensitized photoelectric conversion element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric conversion element which improves its photoelectric conversion efficiency and reduces its weight in the dye-sensitized photoelectric conversion element having an action pole with a metal mesh structure wherein a plurality of metal wires are knitted at a mesh. <P>SOLUTION: In the dye-sensitized photoelectric conversion element 1 having conductivity and having the action pole 5 made from a range where a plurality of linear first base materials 8 and a plurality of linear second base materials 9 are knitted at a mesh, an opening rate of the mesh at the range knitted in the mesh is 0.4-80%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion element used for a dye-sensitized solar cell or the like. More specifically, the present invention relates to a dye-sensitized photoelectric conversion element having a structure excellent in photoelectric conversion efficiency.

The dye-sensitized solar cell has been proposed by a group such as Gretzel et al. In Switzerland, and has attracted attention as a photoelectric conversion element that can obtain high conversion efficiency (for example, see Non-Patent Document 1).
Dye-sensitized solar cells can be significantly reduced in price compared to silicon-based conventional solar cells, but the price of conductive substrates used in power generation units is an obstacle to lower prices It has become. In a dye-sensitized solar cell having a conventional structure, the electrode (window electrode) on which light enters is particularly required to have visible light transmission and high conductivity. A substrate coated with a transparent conductive metal oxide such as indium oxide or fluorine-doped tin oxide has been used. However, there is a problem that the manufacturing cost is relatively high. Therefore, research and development of a dye-sensitized solar cell having a new structure that does not use such an expensive transparent conductive substrate is underway.

  For example, a dye-sensitized solar cell module using a metal wire as an electrode instead of a transparent conductive substrate is disclosed (see Patent Documents 1 to 5). However, metal wires such as copper (Cu) and silver (Ag) having excellent conductivity are inferior in corrosion resistance, and metal wires such as titanium (Ti) and tungsten (W) having excellent corrosion resistance are inferior in conductivity. If a metal wire with poor corrosion resistance is used, corrosion by the electrolyte may occur and the function of the solar cell may be impaired. If a metal wire with poor conductivity is used, the internal resistance of the solar cell will increase. The photoelectric conversion efficiency is lowered. Further, a dye-sensitized solar cell module having a structure in which a Cu metal wire coated with Ti is used and wound around a counter electrode is disclosed (see Patent Document 6). However, in order to increase the light receiving surface, it is necessary to lengthen the metal wire, resulting in a problem that the internal resistance increases. For this reason, a dye-sensitized solar cell module in which a working electrode is formed by knitting a plurality of relatively short metal wires in a mesh shape has also been proposed (see Patent Documents 7 to 10).

Japanese Patent Application No. 2007-012545 Japanese Patent Application No. 2007-012544 JP 2005-196982 A JP 2005-516370 gazette JP 2008-108508 A Japanese Patent Application No. 2008-147262 JP 2001-283944 A JP 2001-283945 A JP 2006-521700 A JP 2006-523369 A

O'Regan B., Graetzel M., Alow cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films, Nature, 1991, 353, 737-739

However, in the conventional mesh-like working electrode, the electrical resistance at the contact point between the metal wires intersecting each other increases due to the influence of titanium oxide applied to the metal wire and the electrolyte solution interposed between the working electrode and the counter electrode. There is a problem that power generation efficiency is lowered. In addition, today, solar cells tend to have a large area, and reduction in weight is desired.
The present invention has been made in view of the above circumstances, and in a dye-sensitized photoelectric conversion element having a working electrode having a network structure in which a plurality of metal wires are knitted in a network shape, the photoelectric conversion efficiency is improved. In addition, a photoelectric conversion element whose weight is reduced is provided.

The dye-sensitized photoelectric conversion element according to claim 1 of the present invention has an action including a region in which a plurality of first and second base materials that are conductive and have a linear shape are knitted in a mesh shape. A dye-sensitized photoelectric conversion element provided with a pole, wherein the aperture ratio of the mesh in the region is 0.4% or more and 80% or less.
The dye-sensitized photoelectric conversion element according to claim 2 of the present invention is a copper wire in which any one or both of the first base material and the second base material are titanium-coated in claim 1, The titanium-coated copper wire has a diameter of 15 μm or more and 150 μm or less.
The dye-sensitized photoelectric conversion element according to claim 3 of the present invention is the dye-sensitized photoelectric conversion element according to claim 1 or 2, wherein at least one of the first base material and the second base material is removed from the region. It has a current collecting wiring composed of a portion extending in the longitudinal direction of the base material, and a current collecting portion electrically connected together by collecting the end portions of the current collecting wiring. And

According to the dye-sensitized photoelectric conversion element of the present invention, the working electrode has an aperture ratio of 0.4% or more and 80% or less than the conventional dye-sensitized photoelectric conversion element by setting the mesh area of the working electrode to 0.4% or more and 80% or less. This reduces the area occupied by the base material per unit area. At this time, since the internal resistance can be kept low by reducing the number of overlapping portions where the first base material and the second base material intersect and contact each other per unit area, the photoelectric conversion efficiency can be improved. . Furthermore, at this time, the weight per unit area can be reduced, and the cost required for the base material per unit area can be reduced.
Further, by setting the aperture ratio of the mesh of the working electrode to 0.4% or more and 80% or less, the electrolyte interposing the working electrode and the counter electrode passes through the opening of the working electrode and increases the diffusion efficiency of the electrolyte. Therefore, the photoelectric conversion efficiency can be improved.
In the dye-sensitized photoelectric conversion device of the present invention, the first base material and the second base material are Ti-coated Cu wires (hereinafter referred to as Ti-coated Cu wires), and the diameter of the Ti-coated Cu wires. Is 15 μm or more and 150 μm or less, it is possible to improve the flexibility of the region knitted in the mesh shape.
In the dye-sensitized photoelectric conversion element of the present invention, at least one of the first base material and the second base material extends in a longitudinal direction of the base material from a region formed by knitting the mesh. In the case of having a current collector wiring composed of an extended portion and a current collector electrically connected together by collecting the end portions of the current collector wiring, the base having the current collector is provided. Since current can be collected directly from the material, the photoelectric conversion efficiency can be further improved.

It is a schematic block diagram of an example of the dye-sensitized photoelectric conversion element which concerns on this invention. It is sectional drawing of an example of the dye-sensitized photoelectric conversion element which concerns on this invention. It is a disassembled perspective view of an example of the dye-sensitized photoelectric conversion element which concerns on this invention.

  Hereinafter, an example of the dye-sensitized photoelectric conversion element according to the present invention will be described in detail with reference to the drawings.

As shown in FIGS. 1 to 3, the dye-sensitized photoelectric conversion device 1 according to the present invention includes a power generation unit 2 having a rectangular shape in plan view and a current collection unit 3 provided outside the power generation unit 2. In this configuration, the electrons generated in the power generation unit 2 are collected in the current collection unit 3 via the current collection wiring unit 4 extending from one side of the power generation unit 2.
The power generation unit 2 is configured such that a working electrode 5 having a mesh structure having a rectangular shape in plan view and a plate-like counter electrode 6 having a rectangular shape in plan view are overlapped via a separator 10. The working electrode 5 having a network structure is provided with a plurality of first base materials 8 and a plurality of second base materials 9 having conductivity, and are arranged around the first base material 8 and the second base material 9 so as to be a sensitizing dye. The porous oxide semiconductor layer 13 is impregnated with the electrolyte 18 together with the sensitizing dye.
Both the first base material 8 and the second base material 9 are linear, and the first base material 8 and the second base material 9 are knitted to form a region having a rectangular mesh structure. An enlarged view of this network structure is shown in FIG.

In FIG. 1B, the plurality of first base materials 8 form a horizontal line, and the plurality of second base materials 9 form a vertical line. Here, the wire diameter of the first base material 8 is expressed as α1, the gap width between the adjacent first base materials 8 is expressed as α2, the wire diameter of the second base material 9 is expressed as β1, and the adjacent second base The gap width between the materials 9 is represented as β2. At this time, the mesh opening ratio U of the working electrode 5 of the mesh structure is obtained as follows.
The vertical and horizontal lengths of the mesh-like region of the working electrode 5 are respectively expressed as X and Y, the number of the first base materials 8 in the region is p, and the number of the second base materials 9 in the region is q. The vertical opening width L is obtained by the equation L = X−α1 × p, the horizontal opening width W is obtained by the equation W = Y−β1 × q, and the aperture ratio U is U = (L XW) / (X * Y) * 100%. That is, the aperture ratio U is an area ratio of a portion not occupied by the first base material 8 and the second base material 9 in the unit area of the mesh region of the working electrode 5. The opening ratio U is 0% when the gap width α2 or the gap width β2 is 0 and the product of the vertical opening width L and the horizontal opening width W is 0.
The dye-sensitized photoelectric conversion element 1 according to the present invention is characterized in that an opening ratio U of a mesh woven region is 0.4% or more and 80% or less.

Next, as shown in FIGS. 1 to 3, the counter electrode 6 is a plate-like conductive base material, and is overlapped with the working electrode 5 with the separator 10 interposed therebetween. The counter electrode 6 has a connection portion 6 a that is paired with the current collector 3, and the connection portion 6 a extends to the outside of the power generation unit 2.
The working electrode 5 and the counter electrode 6 and the separator 10 inserted between them are sandwiched between two upper layers 14, and the inside of the two upper layers 14 is filled with an electrolyte 18. The power generation unit 2 is sealed on four sides by the thermocompression bonding unit 12, whereby the electrolyte 18 is enclosed in the upper covering 14.

  In addition, all of the plurality of first base materials 8 constituting the working electrode 5 are extended outward from the working electrode 5 to become the current collecting wiring portion 4, and the end portions thereof are gathered outside. The current collector 3 is electrically connected.

Hereinafter, each component will be described in detail.
In the dye-sensitized photoelectric conversion element 1 illustrated in FIG. 1, a wire made of Cu wire coated with Ti is used as the first base material 8 and the second base material 9. By covering the center line made of highly conductive Cu wire with Ti having high corrosion resistance, the internal resistance of the working electrode 5 composed of the wire is suppressed, and at the same time, the corrosion of the wire by the electrolytic solution is suppressed. Can do.
The working electrode 5 has a region in which a predetermined number of first base materials 8 and second base materials 9 are knitted in a mesh shape. The first base material 8 and the second base material 9 are knitted so that they are in contact with each other at the overlapping portion, and have a rectangular network structure. At this time, the gap width α2 between the adjacent first base materials 8 and the gap width β2 between the adjacent second base materials 9 so that the opening ratio U of the mesh in the region is 0.4% or more and 80% or less. Is adjusted to the desired width.

The aperture ratio U is preferably 0.5% or more and 70% or less, more preferably 25% or more and 70% or less, and further preferably 40% or more and 70% or less from the viewpoint of further increasing the photoelectric conversion efficiency. By increasing the aperture ratio U, the diffusion efficiency of the electrolyte 18 such as iodine ions contained in the electrolytic solution interposing the working electrode 5 and the counter electrode 6 is increased, and the photoelectric conversion efficiency can be increased. Further, by increasing the aperture ratio U, the number of overlapping portions between the first base material 8 and the second base material 9 in the region knitted in the mesh shape is reduced, and the internal resistance of the region is suppressed to reduce photoelectricity. Conversion efficiency can be increased.
Further, the aperture ratio U is preferably 25% or more and 80% or less, more preferably 40% or more and 80% or less, and further preferably 60% or more and 80% or less, from the viewpoint of improving the lightness of the photoelectric conversion element. By increasing the aperture ratio U, it is possible to reduce the number of base materials per unit area of the region knitted in the mesh shape, to increase the lightness of the region, and to reduce its manufacturing cost. can do.

  The weaving method of the region knitted in a mesh shape is not limited to the plain weave illustrated in FIG. 1, and a method similar to a general cloth weaving method such as twill weave or satin weave can be applied. In the plain weaving, a plurality of vertical lines made of the second base material 9 are alternately divided one above the other on the loom, and the first base material 8 is made between the plurality of vertical lines divided up and down. The process in which the weft is passed and driven with a scissors is one cycle. In the next cycle, the top and bottom of a plurality of vertical lines are replaced with the previous cycle, and the lines are alternately separated one by one again. When weaving in this way, the gap width α2 and the gap width β2 are set to desired widths by appropriately adjusting the interval between the vertical lines during weaving, the tension between the vertical lines and the horizontal lines, and the driving condition of the wrinkles. The desired aperture ratio U can be given to the area knitted in the mesh shape.

  It is preferable that the 1st base material 8 and the 2nd base material 9 are knitted so that it may mutually orthogonally cross in the area | region where they are knitted. By being knitted perpendicularly to each other, the overlapping area (the area where the first base material 8 and the second base material 9 are in contact) at the overlapping portion of the first base material 8 and the second base material 9 is minimized, and this action is performed. The internal resistance of the pole 5 can be suppressed.

  Further, the region knitted in a mesh shape is formed by knitting a plurality of first base materials 8 and a plurality of second base materials 9 so that the first base material 8 and the second base material 9 are knitted. It is superior in flexibility and structural strength than the one constructed without any modification.

The material of the center line of the first base material 8 and the second base material 9 is not limited to pure Cu, for example, a light metal such as magnesium (Mg), a highly conductive metal such as Ag, or these An alloy of metal and Cu is preferable. Furthermore, a metal wire coated with the metal can be used as the center line. For example, an aluminum (Al) wire coated with pure Cu may be used as the center line.
The material for covering the center line is not limited to Ti, and a metal having high corrosion resistance such as W or platinum (Pt), or an alloy of these metals may be used. By using a metal having high corrosion resistance, corrosion of the first base material 8 and the second base material 9 by the electrolyte 18 can be suppressed. Although these materials can also be used as the material for the center line, those exemplified as the material for the center line are more preferable from the viewpoint of enhancing conductivity.

As a method for producing a Ti-coated Cu wire, a known method can be used. For example, Ti is formed into a pipe shape by extrusion molding or the like, and Cu is formed into a linear shape by extrusion molding or the like, and the Cu wire is inserted into the Ti pipe while running these Ti pipe and Cu wire simultaneously, By squeezing them and bringing them into close contact, a Ti-coated Cu wire can be obtained.
A Ti-coated Cu wire produced by such a wire drawing method has better adhesion of the coating layer than that produced by a sputtering method, a plating method or the like, and the production cost can be kept low.

The wire diameters (diameters) of the first base material 8 and the second base material 9 may be any thickness as long as the region formed by the mesh can be formed. It can be appropriately adjusted depending on the strength, and may be, for example, from 10 μm to 200 μm.
When the substrate is a Ti-coated Cu wire, the wire diameter (diameter) is preferably 15 μm or more and 150 μm or less, more preferably 20 μm or more and 100 μm or less, further preferably 30 μm or more and 70 μm or less, and particularly preferably 30 μm or more and 50 μm or less. preferable. By setting it to be equal to or higher than the lower limit of the above range, kinking of the base material in the weaving can be suppressed, and therefore, the manufacture of the region knitted in the mesh shape becomes easy. Moreover, by setting it to the upper limit value or less of the above range, the flexibility, flexibility, and flexibility of the region knitted in the mesh shape can be further enhanced.

In the power generation unit 2 shown in FIG. 1, of the surrounding four sides, the sides located on the sides are the first side 20 and the second side 21, respectively, and the sides located above and below are the third side 22 and the fourth side, respectively. 23, each second base material 9 extends from the third side 22 to the fourth side 23, and a plurality of second base materials 9 are provided from the first side 20 to the second side 21. There are several lines.
A plurality of first base materials 8 are arranged in a predetermined number from the third side 22 to the fourth side 23 and extend from the first side 20 to the current collector 3. That is, all of the first base materials 8 among the base materials constituting the working electrode 5 are drawn out so as to be extended from the power generation section 2 from one side of the power generation section 2 having a rectangular shape. Of the first base material 8, the portion between the second side 21 and the current collector 3 becomes the current collector wiring 4, and the electrons generated at the working electrode 5 pass through this current collector wiring 4. To the current collector.
The extended first base material 8 is subjected to connection processing so as to form a current collecting structure outside the power generation unit 2. The means for connecting is not particularly limited, and for example, all the first base materials 8 may be soldered on a conductive plate material.

Of the first base material 8 and the second base material 9, a porous oxide semiconductor layer 13 is disposed on the surface of a portion having a network structure, and at least part of the surface is a sensitizing dye. And the electrolyte 18 is supported. Of the first substrate 8, the porous oxide semiconductor layer 13 is not disposed on the current collecting wiring portion 4. The semiconductor forming the porous oxide semiconductor layer 13 is titanium oxide (TiO ₂ ). is there. The thickness of the titanium oxide is about 5 μm, but is not particularly limited, and may be, for example, 1 μm to 50 μm.
The semiconductor that forms the porous oxide semiconductor layer 13 is not limited to titanium oxide, and is generally zinc oxide (ZnO), tin oxide (SnO ₂ ), oxidation, as long as it is used for dye-sensitized solar cells. Various semiconductor electrodes such as zinc (ZnO), niobium oxide (Nb ₂ O ₅ ), and tungsten oxide (WO ₃ ) can be used without limitation.

  Examples of the sensitizing dye include ruthenium complexes such as N719, N3, and black dye, metal-containing complexes such as porphyrin and phthalocyanine, and organic dyes such as eosin, rhodamine, and merocyanine. From the above, it is only necessary to appropriately select one having an excitation behavior suitable for the application and the semiconductor used.

  The porous oxide semiconductor layer 13 is impregnated with an electrolytic solution, and this electrolytic solution also constitutes a part of the electrolyte 18. In this case, the electrolyte 18 in the porous oxide semiconductor layer 13 is formed by impregnating the porous oxide semiconductor layer 13 with an electrolytic solution, or impregnating the porous oxide semiconductor layer 13 with an electrolytic solution. Then, the electrolyte solution is gelled (pseudo-solidified) using an appropriate gelling agent and formed integrally with the porous oxide semiconductor layer 13 or based on an ionic liquid Further, a gel electrolyte containing oxide semiconductor particles and conductive particles is used.

As said electrolyte solution, what melt | dissolved electrolyte components, such as an iodine, iodide ion, and tertiary butyl pyridine, in organic solvents and ionic liquids, such as ethylene carbonate and methoxyacetonitrile, is used.
Examples of the gelling agent used for gelling the electrolytic solution include polyvinylidene fluoride, a polyethylene oxide derivative, and an amino acid derivative.
Moreover, if it replaces with volatile electrolyte solution and it is generally used for a dye-sensitized solar cell, not only what a solvent is an ionic liquid or the gelatinized thing but p-type inorganic semiconductor and an organic hole transport layer Even solids such as these can be used without limitation.

Although it does not specifically limit as said ionic liquid, It is a liquid at room temperature, For example, the normal temperature molten salt which used the compound which has the quaternized nitrogen atom as a cation is mentioned.
Examples of the cation of the room temperature molten salt include quaternized imidazolium derivatives, quaternized pyridinium derivatives, and quaternized ammonium derivatives.
Examples of the anion of the room temperature molten salt include BF ₄ ⁻ , PF ₆ ⁻ , (HF) _n ⁻ , bistrifluoromethylsulfonylimide [N (CF ₃ SO ₂ ) ₂ ⁻ ], and iodide ions.
Specific examples of the ionic liquid include salts composed of quaternized imidazolium-based cations and iodide ions or bistrifluoromethylsulfonylimide ions.

  The oxide semiconductor particles are not particularly limited in terms of the type and particle size of the substance, but are excellent in miscibility with an electrolyte mainly composed of an ionic liquid and gel the electrolyte. Is used. In addition, the oxide semiconductor particles are required to have excellent chemical stability against other coexisting components contained in the electrolyte 18 without reducing the semiconductivity of the electrolyte 18. In particular, even when the electrolyte 18 includes a redox pair such as iodine / iodide ions or bromine / bromide ions, the oxide semiconductor particles are preferably those that do not deteriorate due to an oxidation reaction.

Examples of such oxide semiconductor particles include TiO ₂ , SnO ₂ , SiO ₂ , ZnO, Nb ₂ O ₅ , In ₂ O ₃ , ZrO ₂ , Al ₂ O ₃ , WO ₃ , SrTiO ₃ , Ta ₂ O ₅ , One or a mixture of two or more selected from the group consisting of La ₂ O ₃ , Y ₂ O ₃ , Ho ₂ O ₃ , Bi ₂ O ₃ , CeO ₂ is preferable, and the average particle size is about 2 nm to 1000 nm. preferable.

As the conductive fine particles, conductive particles such as a conductor and a semiconductor are used.
Further, the type and particle size of the conductive particles are not particularly limited, and those that are excellent in miscibility with an electrolytic solution mainly composed of an ionic liquid and that gel the electrolytic solution are used. Furthermore, it is necessary to be excellent in chemical stability against other coexisting components contained in the electrolyte 18.
In particular, even when the electrolyte 18 contains an oxidation-reduction pair such as iodine / iodide ions or bromine / bromide ions, an electrolyte that does not deteriorate due to an oxidation reaction is preferable.

  Examples of such conductive fine particles include those composed mainly of carbon, and specific examples include particles such as carbon nanotubes, carbon fibers, and carbon black. All methods for producing these substances are known, and commercially available products can also be used.

The counter electrode 6 is formed of a Ti plate having a conductive plate shape whose surface is nonconductive. The counter electrode 6 has a catalyst film (not shown) made of Pt on the surface.
The configuration of the counter electrode 6 is not limited to the Pt-coated Ti plate as described above, and may be a Pt plate or a metal plate coated with Pt. Alternatively, it may be a carbon plate or a metal plate coated with carbon.
The thickness of the counter electrode 6 may be 40 μm, for example, and the thickness of the coating may be 30 nm, for example, and is not particularly limited.

  A separator 10 made of a nonconductive material is inserted between the working electrode 5 and the counter electrode 6 in order to prevent a short circuit between the working electrode 5 and the counter electrode 6. The material of the separator 10 is polyolefin such as polyethylene, and the thickness is preferably 20 μm or less. However, the material is not limited as long as it can withstand the electrolytic solution and insulate the working electrode 5 and the counter electrode 6.

Further, the working electrode 5, the counter electrode 6, and the separator 10 are configured to be sandwiched between two upper layers 14, thereby sealing the electrolyte 18.
The upper layer 14 has a rectangular shape substantially the same shape as the network structure portion of the working electrode 5 and the counter electrode 6, and the thermocompression bonding parts 12 are formed on the four sides thereof.
The material of the upper layer 14 is not particularly limited as long as it has a high gas barrier property, has chemical resistance to the electrolyte 18, and has optical transparency. Examples of such a material include a high gas barrier film having a resin such as PET as a substrate, a glass plate, and an alkali-free glass plate. Since the high gas barrier film has high flexibility and flexibility, it is suitable for providing the electrode part 2 with flexibility. Moreover, since the said glass plate and an alkali free glass plate are excellent in gas barrier property, chemical resistance, and light transmittance, the durability of the electrode part 2 can be improved. Of the two upper coverings 14, the upper covering 14 on the counter electrode 6 side may not have optical transparency.

When the dye-sensitized photoelectric conversion element 1 having the above-described configuration is connected to the current collector 3 via a connection conductor such as an electric device, light such as sunlight is incident through the translucent upper covering 14. And since it becomes possible to take out all the electrons which generate | occur | produced in the 1st base material 8 among the electrons which generate | occur | produced in the electric power generation part 2, a photoelectric conversion efficiency improves remarkably.
Further, since the power generation unit 2 is a combination of a working electrode 5 having a mesh structure, a thin plate-like counter electrode 6 and an upper cover 14 made of an alkali-free glass plate, it is possible to manufacture a photoelectric conversion element having excellent durability. Become.

  In the dye-sensitized photoelectric conversion element 1 described above, one end of the first substrate 8 extends to form the current collector 3, but a plurality of the current collectors 3 can be provided. For example, the both ends of the first base material 8 may be extended so that the two current collectors 3 sandwich the power generation unit 2, and one end or both ends of the second base material 9 may be extended to similarly A current collector 3 may be provided. By providing the plurality of current collectors 3, the efficiency of extracting electrons generated in the first base material 8 and the second base material 9 can be increased, and the photoelectric conversion efficiency of the photoelectric conversion element 1 can be increased.

[Examples 1-7, Comparative Examples 1-3]
A photoelectric conversion element having the structure shown in FIGS. 1 to 3 was produced as follows.
First, a Ti-coated Cu wire having a wire diameter shown in Table 1 is woven into a mesh shape by a loom so that vertical lines and horizontal lines are orthogonal to each other, and from a region formed by knitting into a mesh shape having an aperture ratio shown in Table 1. Ten types of rectangular (5 cm × 5 cm) working electrodes were produced. It should be noted that one end of the horizontal wire of the Ti-coated Cu wire woven vertically and horizontally was woven so as to be sufficiently long with respect to the other end so as to be drawn outward with respect to the power generation unit in order to form a current collector. The weaving properties of these working electrodes were evaluated according to the following criteria, and the results are also shown in Table 1.
(Evaluation criteria for weaving)
Visual inspection of the mesh structure of the working electrode after weaving showed no bending or breakage: ○
Visual inspection of the mesh structure of the working electrode after weaving showed that it was bent or damaged: ×

Subsequently, the region of the working electrode of each example knitted in the mesh shape is immersed in TiO ₂ paste (manufactured by Solaronix; Ti Nanoxide-T), then pulled up, dried, and immersed again. The process was repeated 3 times. Subsequently, the region woven in the mesh shape coated with TiO ₂ was sintered in an electric furnace at 500 ° C. for 1 hour to obtain the region knitted in the mesh shape with a porous TiO ₂ film. It was. The TiO ₂ film thickness was approximately 10 μm. The TiO2 film sintered on the working electrode in each example was the same amount.

Next, the working electrode of each example was knitted into a network with a TiO ₂ film, and a ruthenium dye (Solaronix, RutheAlum535-bisTBA, generally called N719) 0.3 mM, acetonitrile / tert- It was immersed in a butanol = 1: 1 solution and allowed to stand at room temperature for 24 hours to carry the dye on the TiO ₂ surface. After pulling up from the dye solution, it was washed with the above mixed solvent and used as a working electrode.

  On the other hand, a counter electrode was formed by forming a Pt film on one side of a rolled Ti plate having a thickness of 200 μm by physical vapor deposition. This counter electrode is placed on alkali-free glass, a PET film with a thickness of 1 mm is placed on the counter electrode as a separator, the working electrode is placed on the separator, and the alkali-free glass is placed on the working electrode. did. Thus, three side surfaces were sealed with the thermocompression-bonding agent among the four side surfaces of the cell covered up and down by alkali-free glass.

Next, from one side of the cell that is not sealed, a volatile electrolyte containing methoxyacetonitrile as a solvent is injected to fill the inside of the cell, and then the side is sealed with a thermocompression bonding agent to complete the cell. Sealed.
When sealing the side surface of the cell, one end side of the long horizontal line out of the Ti-coated Cu wire constituting the working electrode was drawn out of the cell, and then the cell was sealed. A plurality of horizontal lines drawn out were soldered to a copper plate to form a current collector. In addition, an ionomer resin was bonded in advance to the thermocompression bonding portions of the working electrode and the counter electrode so as to prevent leakage of the electrolytic solution after sealing.

<Evaluation of photoelectric conversion efficiency>
The solar simulator (AM1.5, 100 mW / cm ² ) was used for light for each of the dye-sensitized photoelectric conversion element cells of Examples 1 to 7 and Comparative Examples 1 to 3 manufactured as described above. Was measured, the current-potential curve was measured, and the photoelectric conversion efficiency was determined. The results are also shown in Table 1.

From the above results, the dye-sensitized photoelectric conversion elements of Examples 1 to 7 according to the present invention are all excellent in photoelectric conversion efficiency as compared with the dye-sensitized photoelectric conversion elements of Comparative Examples 1 to 3. it is obvious.
Moreover, since the aperture ratio of the working electrode of the dye-sensitized photoelectric conversion elements of Examples 1 to 7 according to the present invention is higher than the aperture ratio of the working electrode of the dye-sensitized photoelectric conversion elements of Comparative Examples 1 to 3. As for the weight of the working electrode per unit area, it is clear that the example is lighter than the comparative example. Therefore, it is clear that the dye-sensitized photoelectric conversion elements of Examples 1 to 7 according to the present invention are all superior in light weight as compared with the dye-sensitized photoelectric conversion elements of Comparative Examples 1 to 3.

<Evaluation of flexibility>
Similarly to the above, 10 types of working electrodes of Examples 1-7 and Comparative Examples 1-3 were produced. However, in order to conform to the standard of the MIT testing machine, the size of the region knitted in a mesh shape was changed to 10 mm × 185 mm. The weaving property of this working electrode was evaluated according to the following criteria.
(Evaluation criteria for weaving)
Visual inspection of the mesh structure of the working electrode after weaving showed no bending or breakage: ○
Visual inspection of the mesh structure of the working electrode after weaving showed that it was bent or damaged: ×

Furthermore, the MIT bending test was performed on the working electrode under the following conditions, and the flexibility of each working electrode was evaluated according to the following criteria. The results are also shown in Table 1.
(MIT flex test conditions)
The bending angle was 270 °, the number of bendings was 30,000, the bending speed was 175 times per minute, the tension was 500 gf, and the radius of curvature was 1 mm.
(Evaluation criteria for flexibility)
Visual inspection of the network structure of the working electrode after the test showed no bending or breakage: ○
After the test, the network structure of the working electrode was visually inspected, and there was bending or breakage: ×

  From the above results, it is clear that among the dye-sensitized photoelectric conversion elements of Examples 1 to 7 according to the present invention, the working electrodes of Examples 1 to 6 have excellent flexibility. Therefore, when the alkali-free glass used in the production of the dye-sensitized photoelectric conversion element of the example is replaced with a high gas barrier film having, for example, PET as a substrate, the dye-sensitized photoelectric of the example is used. It is clear that the conversion element has excellent flexibility.

  The present invention is widely applicable to photoelectric conversion elements using metal wires as electrodes.

DESCRIPTION OF SYMBOLS 1 ... Dye-sensitized photoelectric conversion element, 2 ... Power generation part, 3 ... Current collection part, 4 ... Current collection wiring part, 5 ... Working electrode, 6 ... Counter electrode, 8 ... 1st base material, 9 ... 2nd group Materials: 10 ... Separator, 12 ... Thermocompression bonding part, 13 ... Porous oxide semiconductor layer, 14 ... Overlay, 15 ... Network structure part, 18 ... Electrolyte.

Claims (3)

A dye-sensitized photoelectric conversion element comprising a working electrode composed of a region in which a plurality of first base materials and second base materials that are conductive and linear are knitted in a mesh shape,
The dye-sensitized photoelectric conversion element, wherein an opening ratio of the mesh in the region is 0.4% or more and 80% or less.   One or both of the first substrate and the second substrate are titanium-coated copper wires, and the titanium-coated copper wire has a diameter of 15 μm or more and 150 μm or less. 1. The dye-sensitized photoelectric conversion element according to 1. Among the first base material and the second base material, at least one base material is a current collecting wiring composed of a portion extending from the region in the longitudinal direction of the base material;
3. The dye-sensitized photoelectric conversion element according to claim 1, further comprising: a current collecting portion in which end portions of the current collecting wiring are collectively connected.

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