JP2016178117A - Transparent electrode for solar cell and electrode laminate for solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent electrode for a solar cell, which is excellent in conductivity and has high light permeability.SOLUTION: A transparent electrode 3 for a solar cell which is used for a solar cell module and has light permeability includes: a conducting layer 4 having light permeability; and metal wiring 5 at least a part of which is placed inside the conducting layer 4. The metal wiring 5 has higher conductivity than the conducting layer 4, and in the surface direction of the conducting layer 4, the metal wiring 5 is partially placed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transparent electrode for a solar cell that is used in a solar cell module and has light transmittance. Moreover, this invention relates to the transparent electrode laminated body for solar cells provided with the said transparent electrode for solar cells.

In recent years, transparent electrodes having high conductivity and high transmittance in the visible light region have been used for solar cells, liquid crystal display elements, and other various light receiving elements. As such a transparent electrode, a thin film made of a conductive oxide such as tin oxide (SnO ₂ ), zinc oxide (ZnO), or indium oxide (In ₂ O ₃ ), metal wiring, and the like are known. Yes.

  For example, in the following Patent Document 1, an auxiliary metal wiring having a plurality of openings, an auxiliary electrode layer having a transparent resin filled in the openings, and a conductive resin layer formed on the auxiliary electrode layer, A transparent electrode is disclosed. Patent Document 1 describes that the transparent resin is a resin having low affinity with at least the surface of the auxiliary metal wiring.

JP 2013-16671 A

  In the electrode used for a solar cell module, in order to improve photoelectric conversion efficiency compared with the electrode used for another use, the electrode which can make resistance low considerably is desired.

  In solar cell applications, organic materials are used for the support and the photoelectric conversion layer. Therefore, when forming a transparent electrode in the solar cell member which has a support body and a photoelectric converting layer, it is necessary to form a transparent electrode at low temperature so that an organic material may not deteriorate. However, when a transparent electrode material such as a conductive oxide is formed at a low temperature, there is a problem that the crystallinity is deteriorated and the resistance of the electrode is increased.

  Moreover, when the metal wiring is used as the electrode material of the solar cell as in Patent Document 1, the resistance of the electrode can be reduced. However, in Patent Document 1, the opening of the metal wiring is filled with a resin having low affinity with the metal wiring. For this reason, the resin filled in the opening of the metal wiring may not sufficiently reduce the resistance of the electrode.

  An object of the present invention is to provide a transparent electrode for a solar cell that is excellent in conductivity and has high light transmittance, and a transparent electrode laminate for a solar cell using the transparent electrode for a solar cell. That is.

  According to a wide aspect of the present invention, a transparent electrode that is used in a solar cell module and has light transmissivity, the electroconductive layer having light transmissivity, and at least a part thereof is disposed inside the electroconductive layer. Provided is a transparent electrode for a solar cell, comprising a metal wiring, wherein the metal wiring has higher conductivity than the conductive layer, and the metal wiring is partially disposed in a surface direction of the conductive layer Is done.

  On the specific situation with the transparent electrode for solar cells which concerns on this invention, the said metal wiring is arrange | positioned inside the said conductive layer so that it may not protrude from the surface of the said conductive layer.

  On the specific situation with the transparent electrode for solar cells which concerns on this invention, the said metal wiring and the said conductive layer are integrated.

  On the specific situation with the transparent electrode for solar cells which concerns on this invention, the planar shape of the said metal wiring is line shape or mesh shape.

  In a specific aspect of the transparent electrode for a solar cell according to the present invention, an area occupied by a portion where the metal wiring is disposed in an area of 100% of the conductive layer when viewed in plan is 0.1% or more. 5% or less.

  On the specific situation with the transparent electrode for solar cells which concerns on this invention, the said transparent electrode for solar cells is used for the module for solar cells in the state in which the said metal wiring is not exposed. Preferably, the metal wiring is disposed inside the conductive layer so as not to be exposed, or the transparent electrode for solar cell is in a state in which a base film is laminated so that the metal wiring is not exposed. Used in solar cell modules.

  The solar cell transparent electrode laminate according to the present invention comprises a solar cell transparent electrode constituted according to the present invention and a light-transmitting base film, on the surface of the solar cell transparent electrode, A substrate film is disposed.

  The transparent electrode for solar cells according to the present invention includes a light-transmitting conductive layer and a metal wiring at least partially disposed inside the conductive layer. Further, the metal wiring has higher conductivity than the conductive layer, and the metal wiring is partially disposed in the surface direction of the conductive layer. Therefore, the transparent electrode for solar cell of the present invention is excellent in conductivity and has high light transmittance.

Fig.1 (a) is a typical top view of the transparent electrode laminated body for solar cells which concerns on the 1st Embodiment of this invention, FIG.1 (b) is the AA 'line | wire of Fig.1 (a). It is typical front sectional drawing in alignment with. FIG. 2 is a schematic front sectional view showing a first modification of the transparent electrode laminate for solar cells according to the first embodiment of the present invention. FIG. 3 is a schematic front cross-sectional view showing a second modification of the solar cell transparent electrode laminate according to the first embodiment of the present invention. FIG. 4A is a schematic plan view of a transparent electrode laminate for a solar cell according to a second embodiment of the present invention, and FIG. 4B is along the line BB ′ in FIG. It is typical front sectional drawing.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

(First embodiment)
Fig.1 (a) is a typical top view of the transparent electrode laminated body for solar cells which concerns on the 1st Embodiment of this invention, FIG.1 (b) is the AA 'line | wire of Fig.1 (a). It is typical front sectional drawing in alignment with. In FIG. 1, the length, width, thickness, and shape of each layer and metal wiring are appropriately changed from the actual size and shape for convenience of illustration.

  The transparent electrode laminated body 1 for solar cells shown to Fig.1 (a) and (b) is equipped with the base film 2 and the transparent electrode 3 for solar cells. The transparent electrode 3 for solar cells is an electrode used for a solar cell module.

  The base film 2 has high light transmittance. After the transparent electrode laminated body 1 for solar cells is mounted in a solar cell module, the base film 2 may be used as it is as a part of the solar cell module, or may be separated from the solar cell module and separated. Good. The base film 2 may not be formed of a conductive material.

  The transparent electrode 3 for solar cells has high light transmittance. The solar cell transparent electrode 3 includes a conductive layer 4 and a metal wiring 5.

  The conductive layer 4 has a first main surface 4a (surface) and a second main surface 4b (surface). The first main surface 4a and the second main surface 4b face each other. The first main surface 4 a is in contact with the base film 2. The first main surface 4a is a surface on which the base film 2 is disposed. The 2nd main surface 4b is a mounting surface mounted in a solar cell module. The conductive layer 4 is made of a material having high conductivity and high light transmittance.

  The metal wiring 5 is partially disposed in the surface direction of the conductive layer 4. When viewed from above, the solar cell transparent electrode 3 has a portion where the metal wiring 5 is disposed and a portion where the metal wiring 5 is not disposed.

  At least a part of the metal wiring 5 is disposed inside the conductive layer 4. Specifically, in the present embodiment, all of the metal wiring 5 is disposed inside the conductive layer 4. The metal wiring 5 is provided so as to be embedded in the conductive layer 4 and integrated with the conductive layer 4. Further, the metal wiring 5 is disposed inside the conductive layer 4 so as not to protrude from the first main surface 4 a of the conductive layer 4. The metal wiring 5 does not have a protruding portion protruding from the first main surface 4 a of the conductive layer 4. On one surface of the solar cell transparent electrode 3, the surface of the metal wiring 5 and the first main surface 4 a of the conductive layer 4 are connected. In this case, it is assumed that all of the metal wiring 5 is disposed inside the conductive layer 4. When the surface of the metal wiring is continuous with the surface of the conductive layer, or when the surface of the metal wiring is located inside the surface of the conductive layer, all of the metal wiring is disposed inside the conductive layer. Suppose that

  When the base film 2 is not laminated on the solar cell transparent electrode 3, the metal wiring 5 is disposed inside the conductive layer 4 so as to be exposed. When the base film 2 is not laminated on the solar cell transparent electrode 3, the surface of the metal wiring 5 is exposed. In this embodiment, since the base film 2 is laminated | stacked on the transparent electrode 3 for solar cells, the surface of the metal wiring 5 is not exposed. The solar cell transparent electrode 3 is preferably used in a solar cell module in a state where the metal wiring 5 is not exposed. It is preferable that the transparent electrode 3 for solar cells is used for the module for solar cells in the state by which the base film 2 was laminated | stacked so that the metal wiring 5 might not be exposed. In these cases, corrosion of the metal wiring 5 can be suppressed, and a solar cell module that can maintain high photoelectric conversion efficiency over a long period of time is obtained.

  1A, the metal wiring 5 includes a plurality of metal wirings extending in the x direction (first direction) and a plurality of metal wirings extending in the y direction (second direction). Have. The metal wiring 5 extends in a plurality of directions. The y direction is a direction orthogonal to the x direction. In the transparent electrode 1 for solar cells, a plurality of metal wires extending in the x direction and a plurality of metal wires extending in the y direction are integrally formed, and a metal wire 5 having a mesh shape in plan view is formed. . In this embodiment, the mesh-like metal wiring 5 has a lattice shape.

  The metal wiring 5 is formed of a material having a light transmittance lower than that of the conductive layer 4. However, since the metal wiring 4 has an opening because the planar shape is a mesh, light is not blocked in the opening. For this reason, the transparent electrode laminated body 1 for solar cells and the transparent electrode 3 for solar cells have light transmittance as a whole. Therefore, in the solar cell transparent electrode 3, light can be sufficiently guided into the solar cell module despite the use of the metal wiring 5 having light transmittance lower than that of the conductive layer 4.

  The metal wiring 5 is formed of a material having higher conductivity than the conductive layer 4. Therefore, the metal wiring 5 has higher conductivity than the conductive layer 4. In the transparent electrode 3 for solar cells, it forms by integrating the metal wiring 5 and the conductive layer 4 which have high electroconductivity. Therefore, high electroconductivity is expressed in the whole transparent electrode 3 for solar cells. Therefore, in the transparent electrode 3 for solar cells, it is possible to achieve both high conductivity and high light transmittance at a high level.

  FIG. 2 is a schematic front sectional view showing a first modification of the transparent electrode laminate for solar cells according to the first embodiment of the present invention. As shown in FIG. 2, in the solar cell transparent electrode laminate 1 </ b> A and the solar cell transparent electrode 3 </ b> A of the first modified example, the metal wiring 5 is disposed inside the conductive layer 4 </ b> A so as not to be exposed. The metal wiring 5 is embedded in the conductive layer 4A so that the metal wiring 5 is not exposed. Even when the base film 2 is not laminated on the solar cell transparent electrode 3A, the metal wiring 5 is disposed inside the conductive layer 4A so as not to be exposed.

  The metal wiring 5 is provided in the central portion in the thickness direction of the conductive layer 4A inside the conductive layer 4A. Accordingly, the metal wiring 5 is not exposed on either the first or second main surface 4a, 4b side of the conductive layer 4A. The metal wiring 5 may be provided in the central portion in the thickness direction inside the conductive layer 4A, may be provided on the first main surface 4a side in the thickness direction, or the second in the thickness direction. The main surface 4b may be provided.

  FIG. 3 is a schematic front cross-sectional view showing a second modification of the solar cell transparent electrode laminate according to the first embodiment of the present invention. As shown in FIG. 3, in the transparent electrode laminated body 1B for solar cells and the transparent electrode 3B for solar cells of a 2nd modification, it arrange | positions so that a part of metal wiring 5 may be embedded inside the conductive layer 4B. Yes. When the base film 2 is not laminated on the solar cell transparent electrode 3B, the metal wiring 5 is disposed inside the conductive layer 4B so as to be exposed. In the solar cell transparent electrode 3B, the metal wiring 5 is provided inside the conductive layer 4B in a state where a part thereof is exposed and a part thereof is not exposed.

  As shown in FIGS. 1-3, in this invention, at least one part of the metal wiring 5 should just be arrange | positioned inside the conductive layers 4, 4A, 4B. Thereby, both high conductivity and high light transmittance can be achieved at a high level. Moreover, peeling between the conductive layers 4, 4 </ b> A, 4 </ b> B and the metal wiring 5 hardly occurs, and the reliability of the solar cell module can be improved.

  From the viewpoint of preventing oxidation of the metal wiring 5, as shown in the first modification, in the transparent electrode for solar cell 3A, the metal wiring 5 is not exposed inside the conductive layer 4A. It is preferable that it is embedded in.

  Further, as in the second modification, when a part of the metal wiring 5 is exposed, the transparent electrode 3B for the solar cell is laminated with the base film 2 so that the metal wiring 5 is not exposed. In a state, it is preferably used for a solar cell module. It is preferable that the base film 2 is laminated | stacked on the exposed part of the metal wiring 5 in the transparent electrode 3B for solar cells. In this case, even if the metal wiring 5 is not completely embedded in the conductive layer 4, corrosion of the metal wiring 5 can be prevented.

  The transparent electrode for solar cell is arranged inside the conductive layer so that the metal wiring is not exposed, or the base film is laminated so that the metal wiring is not exposed for the transparent electrode for solar cell. In such a state, it is preferably used for a solar cell module.

(Second Embodiment)
FIG. 4A is a schematic plan view of a transparent electrode laminate for a solar cell according to a second embodiment of the present invention, and FIG. 4B is along the line BB ′ in FIG. It is typical front sectional drawing. In FIG. 4, the length, width, thickness, and shape of each layer and metal wiring are appropriately changed from the actual size and shape for convenience of illustration.

  As shown in FIGS. 4A and 4B, the solar cell transparent electrode laminate 21 includes a base film 2 and a solar cell transparent electrode 23. The solar cell transparent electrode 23 includes a conductive layer 24 and a metal wiring 25. The conductive layer 24 has a first main surface 24a (surface) and a second main surface 24b (surface).

  In the solar cell transparent electrode 23, the metal wiring 25 is formed by only a plurality of metal wirings extending in the y direction, and a plurality of metal wirings extending in the x direction are not provided. That is, in the solar cell transparent electrode 23, the metal wiring 25 having a line shape in a planar shape is formed by the plurality of metal wirings extending in the y direction. The shape of the conductive layer 24 is also different from the shape of the conductive layer 4 due to the difference in shape between the metal wiring 25 and the metal wiring 5. Other points are the same as in the first embodiment.

  In the second embodiment, since the planar shape of the metal wiring 25 is a line, light is not easily blocked by the metal wiring 25. Therefore, in the solar cell transparent electrode 23, light can be sufficiently guided into the solar cell despite using the metal wiring 25 having lower light transmittance than the conductive layer 24.

  Also in the second embodiment, since the transparent electrode 23 for solar cells is formed by integrating the metal wiring 25 having high conductivity and the conductive layer 24, the transparent electrode 23 for solar cells is formed. Overall, high conductivity can be expressed.

  Since the transparent electrode laminate for solar cells according to the present invention, such as the transparent electrode laminate 1 for solar cells and the transparent electrode laminate 21 for solar cells, has the above-described configuration, it has high conductivity and high light transmission. Both of sex can be achieved at a high level. Therefore, the transparent electrode laminated body for solar cells according to the present invention can be suitably used for solar cell applications.

(Base film)
The base film preferably has high light transmittance. Accordingly, the material of the base film is not particularly limited. For example, polyolefin, polyethersulfone, polysulfone, polycarbonate, cycloolefin polymer, cycloolefin copolymer, polyarylate, polyamide, polyimide, polymethyl methacrylate, polyethylene terephthalate, Examples include polybutylene terephthalate, polyethylene naphthalate, triacetyl cellulose, and cellulose nanofiber. The base film is preferably formed of a resin. These may be used alone or in combination.

  After the transparent electrode laminate for solar cells is mounted on the solar cell module as described above, the base film may be used as a part of the solar cell module as it is, or peeled off and separated from the solar cell module. May be.

  Although the thickness of a base film is not specifically limited, It is preferable that it is 5 micrometers or more, It is more preferable that it is 20 micrometers or more, It is preferable that it is 1000 micrometers or less, It is more preferable that it is 250 micrometers or less. When the thickness of the base film is not more than the above upper limit and not less than the above lower limit, the light transmittance of the solar cell transparent electrode laminate can be further increased, and the thickness can be further reduced.

  Moreover, as for the light transmittance of a base film, it is preferable that the average transmittance | permeability in the visible light region with a wavelength of 380-780 nm is 85% or more, and it is more preferable that it is 90% or more.

  Further, the base film may contain various stabilizers, ultraviolet absorbers, plasticizers, lubricants, or colorants.

(Conductive layer)
The conductive layer is made of a light-transmitting conductive material. The material of the conductive layer is appropriately selected so that the metal wiring has higher conductivity than the conductive layer. The level of conductivity can be evaluated by a four-terminal method using a surface resistance meter (trade name: Loresta-EP, manufactured by MITSUBISHI CHEMICAL ANALYTECH).

As the conductive material is not particularly limited, for example, IZO (indium zinc oxide) or, In-based oxides such as ITO (indium tin _oxide), Sn, such as SnO 2, FTO (fluorine-doped tin oxide) Oxide, AZO (aluminum zinc oxide), Zn oxide such as GZO (gallium zinc oxide), sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum - lithium alloy, Al / _Al 2 _{O 3} mixture, Al / LiF mixture, a metal such as gold, CuI, Ag nanowire (AgNW), such as carbon nanotubes (CNT) or conductive transparent polymers. These may be used alone or in combination.

From the viewpoint of further increasing the conductivity and further increasing the light transmittance, the conductive material is selected from In-based oxides such as IZO (indium zinc oxide) and ITO (indium tin oxide), SnO ₂ , FTO. Sn-based oxides such as (fluorine-doped tin oxide), Zn-based oxides such as AZO (aluminum zinc oxide) and GZO (gallium zinc oxide) are preferable, and ITO (indium tin oxide) is preferable. Is more preferable.

  The thickness of the conductive layer is not particularly limited, but is preferably 15 nm or more, more preferably 20 nm or more, preferably 200 nm or less, and more preferably 100 nm or less.

  When the thickness of a conductive layer is more than the said minimum, the electroconductivity of the transparent electrode for solar cells can be improved further. When the thickness of a conductive layer is below the said upper limit, the light transmittance of the transparent electrode for solar cells can be improved further, and thickness reduction can be achieved further.

  Further, the light transmittance of the conductive layer is preferably 85% or more, more preferably 90% or more, in the visible light region.

(Metal wiring)
The material for the metal wiring is not particularly limited as long as it is a conductive material. However, the material of the metal wiring is appropriately selected so that the metal wiring has higher conductivity than the conductive layer.

  Examples of the conductive material for the metal wiring include gold, platinum, iron, copper, silver, aluminum, chromium, cobalt, stainless steel, and alloys thereof, among others, such as copper, silver, aluminum, and gold. Low resistance metals are preferred. As the conductive material constituting the metal wiring, silver or copper is more preferable, and copper is more preferable because manufacturing cost and material cost are low and oxidation is difficult.

  The planar shape of the metal wiring is not particularly limited, and examples thereof include a mesh shape having a plurality of openings such as a line shape, a square shape, a rectangular shape, and a rhombus shape, a honeycomb, and a curve. Good. From the viewpoint of further improving the electrical conductivity and light transmittance, the planar shape of the metal wiring is preferably a mesh having a plurality of openings such as squares, rectangles, and rhombuses. The lattice shape is included in the mesh shape.

  The area of the metal wiring is not particularly limited, but when viewed in plan, the area occupied by the portion where the metal wiring is disposed in the area of 100% of the conductive layer may be 0.1% or more. Preferably, it is 0.2% or more, more preferably 5% or less, and even more preferably 1% or less. When the area of the metal wiring is not less than the above lower limit, the conductivity can be further increased. When the area of the metal wiring is not more than the above upper limit, the high light transmittance can be further increased. The area of the conductive layer 100% indicates the total of the portion where the metal wiring is arranged and the portion where the metal wiring is not arranged. When the metal wiring is arranged inside the conductive layer so as not to be exposed, the portion where the metal wiring is arranged is recognized through the conductive layer in plan view.

  Although it does not specifically limit as a width | variety of metal wiring, It is preferable that it is 0.1 micrometer or more, It is more preferable that it is 0.5 micrometer or more, It is preferable that it is 50 micrometers or less, It is more preferable that it is 10 micrometers or less.

  When the width | variety of metal wiring is more than the said minimum, the electroconductivity of the transparent electrode for solar cells can be improved further. When the width of the metal wiring is less than or equal to the above upper limit, the light transmittance can be further enhanced.

  Although it does not specifically limit as thickness of metal wiring, It is preferable that it is 5 nm or more, It is more preferable that it is 10 nm or more, It is preferable that it is 200 nm or less, It is more preferable that it is 100 nm or less.

  When the thickness of metal wiring is more than the said minimum, the electroconductivity of the transparent electrode for solar cells can be improved further. When the thickness of the metal wiring is not more than the above upper limit, the thickness can be further reduced.

  When the metal wiring is in the form of a line or a lattice, the interval between adjacent metal wirings is preferably 1 mm or more, preferably 5 mm or more, more preferably 8 mm or more, and 50 mm or less. It is preferable that it is 20 mm or less.

(Production method)
The manufacturing method of the transparent electrode laminated body for solar cells is not specifically limited. As a manufacturing method of the transparent electrode laminated body for solar cells, the following methods are mentioned, for example.

  First, metal wiring is formed on a base film. The method for forming the metal wiring is not particularly limited. For example, a method of etching a metal film formed by vapor deposition or sputtering, various printing methods such as screen printing or inkjet printing, and a known patterning method such as a photolithography method using a resist can be used. By such a patterning method, a metal wiring having a planar shape such as a line shape or a mesh shape can be formed.

  Next, a conductive layer is formed so as to bury at least a part of the obtained metal wiring. Thereby, the transparent electrode for solar cells in which the metal wiring and the conductive layer are integrated is obtained. The conductive layer is formed of a material having lower conductivity than the metal wiring, and preferably formed of a material having higher light transmittance than the metal wiring.

  The method for forming the conductive layer is not particularly limited, and examples thereof include sputtering, vapor deposition, ion plating, CVD, ALD, spray CVD, mist CVD, PLD, and the like. Alternatively, a vapor deposition method is preferable, and a sputtering method is more preferable.

  When forming a conductive layer on a metal wiring by a vapor deposition method or a sputtering method, the metal wiring and the conductive layer can be integrated, and the conductivity of the obtained transparent electrode for solar cell can be further enhanced.

  When the thickness of a conductive layer is more than the said minimum, the electroconductivity of the transparent electrode for solar cells can be improved further. When the thickness of a conductive layer is below the said upper limit, the light transmittance of the transparent electrode for solar cells can be improved further.

  Hereinafter, the present invention will be specifically described with reference to examples. The present invention is not limited only to the following examples.

Example 1
A Cu layer was deposited to a thickness of 10 nm on a 50 μm PET film by vapor deposition to obtain a Cu-PET film. A dry film resist was attached to the obtained Cu-PET film, and exposure and development were performed so as to form a lattice shape having a line width of 10 μm and a line interval of 20 mm. Subsequently, etching, peeling, washing, and drying steps were performed in this order to obtain a film having Cu wiring (metal wiring) in a grid pattern with a wiring thickness of 10 μm and a wiring interval of 20 mm. On the obtained film, an ITO (SnO ₂ content 7%) layer (transparent conductive layer) of 20 nm was laminated by a DC sputtering method to obtain a transparent electrode for a solar cell of the present invention.

(Examples 2 to 4)
A transparent electrode for a solar cell was obtained in the same manner as in Example 1 except that the wiring interval was changed as shown in Table 1 below.

(Examples 5-6)
A transparent electrode for a solar cell was obtained in the same manner as in Example 1 except that the thickness of the transparent conductive layer was changed as shown in Table 1 below.

(Example 7)
A transparent electrode for a solar cell was obtained in the same manner as in Example 1 except that the material of the metal wiring was changed to Ag.

(Example 8)
A transparent electrode for a solar cell was obtained in the same manner as in Example 1 except that the transparent conductive layer was made of AZO (Al ₂ O ₃ content 5%).

<Evaluation>
The following evaluation was performed about the transparent electrode for solar cells obtained in Examples 1-8. The results are shown in Table 1 below.

(1) Evaluation of transparency (measurement of total light transmittance)
About the obtained transparent electrode for solar cells, the total light transmittance (%) was measured using the haze meter (Murakami Color Research Laboratory company make, product number: HM-150). In addition, the measurement was performed using the test piece which cut out the transparent electrode into the magnitude | size of 50 mm length and 50 mm width according to JISK7361-1. Three test pieces were used. The total light transmittance was determined from the average of the three measurements.

(2) Conductivity evaluation (measurement of surface resistance)
About the obtained transparent electrode for solar cells, surface resistance (Ω / sq) was measured by a four-probe method using a resistivity meter (manufactured by Mitsubishi Chemical Analytech Co., Ltd., product number: Loresta AX MCP-T370).

  As is clear from Table 1, in Examples 1 to 8, it was confirmed that a transparent electrode for a solar cell having a low resistance value and a high total light transmittance was obtained.

DESCRIPTION OF SYMBOLS 1,1A, 1B, 21 ... Transparent electrode laminated body for solar cells 2 ... Base film 3, 3A, 3B, 23 ... Transparent electrode for solar cells 4, 4A, 4B, 24 ... Conductive layer 4a ... 1st main surface 4b ... 2nd main surface 5,25 ... Metal wiring

Claims (8)

A transparent electrode used in a solar cell module and having light transparency,
A conductive layer having optical transparency, and a metal wiring at least partially disposed inside the conductive layer,
The metal wiring has higher conductivity than the conductive layer;
The transparent electrode for solar cells, wherein the metal wiring is partially disposed in the surface direction of the conductive layer.   The transparent electrode for solar cells according to claim 1, wherein the metal wiring is disposed inside the conductive layer so as not to protrude from the surface of the conductive layer.   The transparent electrode for solar cells according to claim 1 or 2, wherein the metal wiring and the conductive layer are integrated.   The transparent electrode for solar cells according to any one of claims 1 to 3, wherein a planar shape of the metal wiring is a line shape or a mesh shape.   5. The area occupied by a portion where the metal wiring is arranged in 100% of the area of the conductive layer when viewed in a plane is 0.1% or more and 5% or less. The transparent electrode for solar cells according to item.   The transparent electrode for solar cells of any one of Claims 1-5 used for the module for solar cells in the state in which the said metal wiring is not exposed.   The metal wiring is disposed inside the conductive layer so as not to be exposed, or the transparent electrode for solar cell is a solar cell in a state where a base film is laminated so that the metal wiring is not exposed. The transparent electrode for solar cells of Claim 6 used for a module for solar cells. The transparent electrode for solar cells according to any one of claims 1 to 7, and a base film having optical transparency,
The transparent electrode laminated body for solar cells by which the said base film is arrange | positioned on the surface of the said transparent electrode for solar cells.

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