JP2013102055A - Transparent electrode substrate and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent electrode substrate suitable for use in an organic thin-film solar cell, and a method for manufacturing a transparent electrode substrate, which is inexpensive and facilitates area enlargement.SOLUTION: A transparent electrode substrate 1 comprises a plate-like transparent substrate 2, a transparent resin layer 3 formed on one side of the transparent substrate 2, a pattern electrode 4 embedded in an opposite surface of the transparent resin layer 3 to the transparent substrate 2, and a transparent collector electrode 5 formed directly on the transparent resin layer 3 and the pattern electrode 4. A surface 15 of the collector electrode 5 is flat.

Description

  The present invention relates to a transparent electrode substrate that can be used in organic thin-film solar cells, dye-sensitized solar cells, organic EL elements, and the like.

  Transparent electrodes are used on the light-receiving surface side of photoelectric conversion elements such as organic thin-film solar cells (OPV) and dye-sensitized solar cells (DSC), and on the light-emitting surface side of light-emitting elements such as organic EL elements (OLED).

  An example of the structure of OPV is shown in FIG. The OPV 31 has a structure in which functional layers such as a hole transport layer 35, an active layer 36, and an electron transport layer 37 are sandwiched between a transparent electrode 33 formed on the transparent substrate 2 ′ and an aluminum electrode 38, The surface of the transparent substrate 2 ′ is a light receiving surface 11 ′. Indium tin oxide (ITO) is often used for the transparent electrode 33. However, in order to obtain a sufficiently low resistance, it is necessary to form a ITO film with a thickness of 300 to 400 nm, resulting in poor productivity and cost. There was a problem that it took. Further, even when a flexible material made of resin or the like is used for the transparent substrate 2 ′, there is a problem that the flexibility of the OPV is impaired because the ITO layer is hard.

  On the other hand, an electrode that combines an ITO layer in contact with the entire surface of the functional layer and a grid-like metal electrode (hereinafter simply referred to as “grid electrode”) has been developed. Thereby, since the film thickness of ITO can be made thin, maintaining the resistance value of the whole electrode, productivity can be improved more and cost can be reduced. Moreover, when this uses the transparent base material which has flexibility, it can maintain without impairing the flexibility of OPV.

  At this time, if a grid electrode is simply formed on a transparent substrate and an ITO layer is formed thereon, the ITO film may be interrupted at the step between the transparent substrate and the grid electrode, and a continuous film may not be formed. . This is because the thickness of the grid electrode is typically several to several tens of μm, whereas the thickness of the ITO film is typically several tens of nm. Therefore, a method has been developed in which the opening of the grid electrode is filled with resin to reduce the step.

  In Patent Document 1, as a transparent electrode substrate for DSC, a metal film having an opening is provided on a transparent base material, and a transparent resin film is provided in the opening so as to have substantially the same thickness as the metal film. A configuration in which a transparent conductive film is provided on a metal film and a transparent resin film is described.

  Patent Document 2 describes an electrode substrate for DSC in which a transparent electrode and a porous semiconductor electrode are sequentially formed on one side of a transparent base material. The transparent electrode includes a metal first conductive layer having a large number of openings, a planarized transparent layer embedded in the openings, and a metal formed on the first conductive layer and the planarized transparent layer. And a second conductive layer made of an oxide.

JP 2005-332705 A JP 2005-158737 A

  However, in the transparent electrode substrate described in Patent Documents 1 and 2, a step of about several μm may inevitably remain between the metal electrode surface and the transparent resin layer or planarized transparent layer of the opening. I understood. This is because the transparent resin layer is cured with the surface exposed after the transparent resin layer is applied to the metal electrode opening. For example, in a method in which a photosensitive resin is used for exposure from the transparent substrate side and the unexposed resin portion on the metal electrode is washed, it is inevitable that the resin layer at the metal electrode opening becomes thick. Further, even if the excess resin is removed with a squeegee before curing, the surface does not become completely flat, and the influence of shrinkage of the resin accompanying the curing remains.

  If there is a step between the surface of the metal electrode and the surface of the resin layer in the opening, the step is reproduced as it is on the surface of the ITO or other transparent electrode formed on the both. This is because the film thickness of ITO or the like is orders of magnitude smaller than the step. Patent Documents 1 and 2 assume DSC applications, and it is sufficient that a transparent conductive film such as ITO can be formed without interruption, so this level difference may not be a problem. However, in the OPV application, since the thickness of the functional layer is as thin as about 100 to 200 nm, this step can be a problem. Further, even in an OLED application having an element structure almost the same as OPV, this step can be a problem.

  On the other hand, with regard to the manufacturing method, in the conventional technique, a grid electrode can be produced using processes such as photolithography, silver halide development, and laser exposure, or the produced grid can be grown thickly by a method such as plating. Has been done. However, these are not cheap processes and are not suitable for increasing the product area.

  The present invention has been made in consideration of these points, and an object thereof is to provide a transparent electrode substrate suitable for use in OPV and OLED. In addition, an object of the present invention is to provide a method for producing a transparent electrode substrate that is inexpensive and can easily increase the product area.

  The transparent electrode substrate of the present invention is embedded in a plate-like transparent substrate, a transparent resin layer formed on one side of the transparent substrate, and a surface of the transparent resin layer opposite to the transparent substrate. And the transparent resin layer and the transparent current collecting electrode formed immediately above the pattern electrode, and the surface of the current collecting electrode is flat. By this structure, it can be set as the transparent electrode base material suitable also for use to OPV and OLED.

Preferably, the pattern electrode has a saddle shape in cross section.
Preferably, the pattern electrode includes conductive particles.
Preferably, the pattern electrode is mainly composed of silver.

Preferably, a step between a portion formed on the pattern electrode and a portion formed on the transparent resin layer on the surface of the collecting electrode is a portion on the pattern electrode on the surface of the collecting electrode. The surface roughness Rz is less than or equal to or less than the surface roughness Rz of the portion of the collector electrode surface on the transparent resin layer.
Preferably, the surface roughness Rz of the portion on the transparent resin layer on the surface of the current collecting electrode is 100 nm or less.
Further, the surface roughness Rz of the portion formed on the pattern electrode on the surface of the current collecting electrode is equal to or greater than the surface roughness Rz of the portion formed on the transparent resin layer.
Here, the surface roughness Rz refers to the maximum height Rz of the contour curve defined in JIS B0601-2001 (the same content as ISO4287-1997). Rz is meant.

  The method for producing a transparent electrode substrate of the present invention is a method for producing any one of the above transparent electrode substrates, the step of printing a pattern electrode on the surface of the release film, and the surface of the release film and the pattern electrode A step of forming a transparent resin layer, a step of laminating a transparent substrate on the transparent resin layer, a step of peeling the release film, a pattern electrode embedded in the transparent resin layer and the surface thereof And a step of forming a transparent current collecting electrode on the surface.

  Another transparent electrode substrate manufacturing method of the present invention includes a step of printing a pattern electrode on the surface of a release film, a step of forming a transparent resin layer on the transparent substrate, and a surface of the transparent resin layer. The step of laminating the release film with the pattern electrode side inward, the step of curing the transparent resin layer, the step of peeling the release film, the pattern embedded in the transparent resin layer and the surface thereof Forming a transparent current collecting electrode on the surface of the electrode.

  Another transparent electrode substrate manufacturing method of the present invention includes a step of forming a transparent collector electrode on the surface of a release film, a step of printing a pattern electrode on the surface of the collector electrode, the release film, The method includes a step of forming a transparent resin layer on the surface of the pattern electrode, a step of laminating a transparent substrate on the transparent resin layer, and a step of peeling the release film.

Preferably, in any of the above manufacturing methods, the step of printing the pattern electrode is a step of screen printing a paste containing conductive particles.
Preferably, in any of the above manufacturing methods, the release film has a surface roughness Rz of 50 nm or less.

  Since the transparent electrode substrate of the present invention has sufficient flatness, it is suitable for use in OPV and OLED. Moreover, according to the manufacturing method of the transparent electrode base material of this invention, a product of a large area can be manufactured cheaply.

It is a figure which shows the structure of the transparent electrode base material which is embodiment. It is a figure which shows the structural example of an organic thin film solar cell (OPV). It is a figure which shows the cross-sectional shape of a pattern electrode. It is a figure which shows the opening part shape of a pattern electrode. It is a conceptual diagram explaining the roughness and level | step difference of a transparent resin layer interface and a pattern electrode interface. It is a figure which shows the process of the transparent electrode base material manufacturing method which is one Embodiment. It is a figure which shows the process of the transparent electrode base material manufacturing method which is other embodiment. It is a figure which shows the process of the transparent electrode base material manufacturing method which is other embodiment. It is a figure which shows the process of the transparent electrode base material manufacturing method which is other embodiment. 2 is a cross-sectional SEM photograph of the transparent electrode substrate of Example 1. 2 is a cross-sectional SEM photograph of the transparent electrode substrate of Example 1. .

  One embodiment of the transparent electrode substrate of the present invention will be described with reference to FIG.

  In the transparent electrode substrate 1 according to this embodiment, a transparent resin layer 3 is formed on a transparent substrate 2, and a pattern electrode 4 is embedded on the upper surface of the transparent resin layer 3. A transparent collector electrode 5 is provided immediately above the electrode 4. The surface 15 of the current collecting electrode 5 is flat. The collector electrode-transparent resin layer interface 13 and the collector electrode-pattern electrode interface 14 are also flat, and there is no step between the interfaces 13 and 14. When the transparent electrode substrate 1 is used for OPV, a functional layer is formed on the surface 15 of the collector electrode 5 and light enters from the light receiving surface 11 side.

  In the transparent electrode substrate, the transmittance is an important characteristic. In the transparent electrode substrate 1 of the present embodiment, the total light transmittance of light perpendicularly incident on the light receiving surface 11 is preferably 80% or more, and more preferably 85% or more. In this specification, the total light transmittance refers to a value measured according to the standard of JISK7105-1981.

  In the transparent electrode substrate, the resistance value is also an important characteristic. This is because if the resistance value is too high, the internal resistance of the device, which is a product, increases, and the power generation efficiency of OVP deteriorates. In the transparent electrode substrate 1 of the present embodiment, the sheet resistance value is preferably 50Ω / □ or less, and more preferably 5Ω / □ or less. The sheet resistance value can be measured by a four-probe method according to the standard of JISK 7194-1994. In the measurement, at least one electrode wire of the pattern electrode is included between the two central probes (voltage measurement probes).

  Various glass substrates and resin films can be used for the transparent substrate 2. Among these, a flexible resin film is preferable in that a flexible product can be manufactured. As the resin film, a single-layer or multilayer film made of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), cyclic polyolefin (COP), polycarbonate (PC), acrylic resin such as PMMA, and other various resins can be used. . The thickness of the transparent substrate 2 is not particularly limited, but a resin film having a thickness of 50 to 350 μm can be suitably used.

  Further, an abrasion resistant layer (hard coat) or an antireflection layer may be formed on the surface of the transparent substrate 2. This improves the wear resistance and the total light transmittance of the transparent electrode substrate. Further, the transparent substrate 2, the wear-resistant layer, and the antireflection layer may contain an ultraviolet (UV) absorber. Thereby, degradation of the transparent electrode base material 1 resulting from UV, yellowing, etc. can be suppressed during the use period of the product using the transparent electrode base material 1. Even when the transparent resin layer 3 made of a UV curable resin is used as will be described later, if the intensity of UV to be irradiated is appropriately selected, UV irradiation is performed through the transparent base material 2 containing the UV absorber. The transparent resin layer 3 can be cured.

  The transparent resin layer 3 is formed on one side of the transparent substrate 2. The transparent resin layer may be directly formed on the surface of the transparent substrate, or may be formed on the transparent substrate via an appropriate adhesive layer. For the transparent resin layer 3, acrylic, ester, silicone, epoxy, and other various transparent resins can be used. Especially, it is preferable to use active energy ray curable resin, and it is more preferable to use UV curable resin from the point which a hardening process becomes easy in the manufacturing process mentioned later. The transparent resin layer 3 may be a single layer or may be composed of a plurality of layers.

  The pattern electrode 4 is embedded in the surface of the transparent resin layer 3 opposite to the transparent substrate 2. That is, in FIG. 1, the entire side surface and bottom surface of the pattern electrode 4 except the top surface (planar portion) are in contact with the transparent resin layer 3. With this structure, even when a product such as OPV is bent, the stress due to deformation is relieved in the transparent resin layer, and the stress is not concentrated at the interface between the pattern electrode and the transparent resin layer. Can be prevented. Moreover, since the entire side surface and bottom surface of the pattern electrode 4 are covered with the transparent resin layer 3, the pattern electrode 4 is not in contact with the transparent substrate 2. When the pattern electrode includes conductive fine particles, if the pattern electrode and the transparent substrate are in contact with each other, the conductive fine particles easily fall off during deformation of the product, but this structure can prevent the conductive fine particles from falling off.

  In order to realize a structure in which the pattern electrode 4 is embedded in the transparent resin layer 3, the thickness of the transparent resin layer 3 needs to be larger than the thickness of the pattern electrode 4. Further, if the transparent resin layer in contact with the bottom of the pattern electrode 4 is too thin, the stress relaxation effect at the time of product deformation is reduced, so the thickness of the transparent resin layer 3 is equal to or greater than the thickness of the pattern electrode 4 and is 1.5 times The above is preferable.

  As the material of the pattern electrode 4, various conductive materials such as various metals such as silver, copper, gold, nickel, aluminum, tin, or alloys thereof, or a mixture of these and carbon can be used. Among these, the pattern electrode 4 preferably contains conductive fine particles, and more preferably contains silver fine particles. When the pattern electrode includes conductive fine particles, the so-called anchor effect improves the adhesion between the pattern electrode and the current collecting electrode, resulting in an effect of reducing the electrical resistance at the current collecting electrode-pattern electrode interface 14. This anchor effect is particularly effective when the metal fine particles are silver fine particles and the current collecting electrode is made of ITO because both materials are not “familiar”. Furthermore, when the pattern electrode includes metal fine particles, it is preferable to simultaneously include an organic substance that functions as a binder.

  The cross-sectional shape of the pattern electrode 4 is preferably a bowl shape as shown in FIG. That is, in the cross-sectional shape, the collector electrode-pattern electrode interface 14 portion is a straight line, and the width parallel to the interface 14 is maximum near the interface 14 and gradually decreases as the distance from the interface 14 increases. It is preferable that the interface between 4 and the transparent resin layer 3 does not have a sharp portion. Further explanation based on FIG. 3, the cross-sectional shape is typically as shown in FIG. 3A, but the portion corresponding to the bottom of the ridge may have a substantially linear portion (FIG. 3B) The electrode thickness need not be maximized at the center (FIG. 3C). In the present specification, the saddle shape includes not only FIG. 3A but also shapes such as FIG. 3B and FIG. 3C. When the pattern electrode has such a cross-sectional shape, stress concentration when the product such as OPV is bent can be avoided, and peeling of the interface and damage to the transparent resin layer 3 and the pattern electrode 4 can be prevented.

  The cross-sectional dimension of the pattern electrode 4 can be designed according to the conductivity of the material constituting the electrode, but the maximum width is preferably 10 to 100 μm and the thickness is 1 to 50 μm. preferable. This is because if the cross section is too small, the possibility of disconnection increases, and if the cross section is too large, the light transmittance decreases.

  The shape (pattern) of the pattern electrode 4 is not particularly limited, but a shape such as a rectangle, a rhombus, and a turtle shell can be suitably used. When the pattern electrode has a lattice shape, each opening has a shape such as a rectangle or a rhombus. At this time, it is preferable that the corner of each opening is not sharp. Referring to FIG. 4 as an example, the opening 16 of the pattern electrode 4 is square, and the corner 17 (vertex of the square) of the opening 16 is not sharp. The radius of curvature of the corner 17 of the opening is preferably 1 μm or more. Since the corner 17 of the opening is not sharp, stress concentration when a product such as OPV is bent can be avoided, and peeling of the interface between the transparent resin layer 3 and the pattern electrode 4 can be prevented.

  The aperture ratio of the pattern electrode 4 is preferably 95% or more, and more preferably 97% or more, in order to increase the total light transmittance.

  The collecting electrode 5 is formed so as to cover the transparent resin layer 3 and the pattern electrode 4. Thereby, the current collecting electrode is electrically connected to the pattern electrode 4. Examples of the material constituting the collecting electrode 5 include oxides such as indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and zinc oxide, and poly (3,4-ethylenedioxy) doped with polystyrene sulfonic acid. Various transparent conductive materials such as a conductive polymer such as thiophene (PEDOT / PSS) can be used. The collecting electrode 5 may be a single layer or may be composed of a plurality of layers. If the thickness of the current collecting electrode 5 is too thin, the resistance increases, and if it is too thick, the productivity is poor, the cost is increased, and the flexibility of the product is impaired. Therefore, the thickness of the collecting electrode 5 is preferably 10 to 150 nm, and more preferably 10 to 30 nm.

  The surface 15 of the current collecting electrode 5 is flat. The total thickness of the OPV functional layers (35, 36, and 37 in FIG. 2) is 100 to 200 nm, and the thickness of the hole transport layer (35) is 30 to 100 nm. Therefore, when these functional layers are laminated on the surface 15 of the current collecting electrode 5, the surface 15 of the current collecting electrode 5 needs to be sufficiently flat so that the function is not impaired.

  The flatness of the collector electrode surface 15 strongly depends on the method of manufacturing the transparent electrode substrate 1. When the current collecting electrode 5 is formed on the surface of the transparent resin layer 3 and the pattern electrode 4, the shape of the current collecting electrode surface 15 is the surface of the transparent resin layer 3 and the pattern electrode 4 before forming the current collecting electrode. Almost the same as the shape. This is because the thickness of the collecting electrode 5 is as small as several tens to several hundreds nm. In the case where the collecting electrode 5 is formed by a method such as vapor deposition or sputtering, this tendency is particularly remarkable because the uniformity of the film thickness is high. FIG. 5 schematically shows the cross-sectional shape of the current collecting electrode in this case. In FIG. 5, the surface roughness Rz of the current collecting electrode is the surface roughness 23 of the portion formed on the transparent resin layer, and the surface roughness 23 'of the transparent resin layer that is the base is formed on the pattern electrode. The surface roughness 24 of the portion is substantially equal to the surface roughness 24 ′ of the pattern electrode serving as the base. In addition, if there is a step 25 ′ between the transparent resin layer surface 13 and the pattern electrode surface 14 as a base, the surface formed on the pattern electrode and the portion formed on the transparent resin layer also on the surface of the collecting electrode The step 25 is reproduced.

  If the step 25 is smaller than the surface roughness 23 of the portion formed on the transparent resin layer or the surface roughness 24 of the portion formed on the pattern electrode on the current collecting electrode surface 15, the step 25 is Since it will be buried in the unevenness | corrugation of the electrode surface, the influence of the level | step difference 25 will become small. Therefore, the level difference 25 on the surface of the collecting electrode 15 is less than the surface roughness Rz24 of the portion on the pattern electrode on the surface of the collecting electrode, or less than the surface roughness Rz23 on the portion of the surface of the collecting electrode on the transparent resin layer. Preferably there is.

  Further, if the surface roughness 23 itself of the portion on the transparent resin layer that occupies most of the surface of the current collecting electrode is large, the flatness of the surface of the current collecting electrode is also impaired. Therefore, the surface roughness 23 of the portion on the transparent resin layer on the surface of the current collecting electrode is preferably 100 nm or less, and more preferably 50 nm or less. Furthermore, the step is preferably 20 nm or less, and more preferably 10 nm or less.

  The configuration of the transparent electrode substrate of the present invention is not limited to the above embodiment. For example, an adhesive layer may be provided between the transparent substrate 2 and the transparent resin layer 3. As will be described later, if the transparent substrate 2 is laminated before the transparent resin layer 3 is cured, the transparent substrate and the transparent resin layer can be bonded together without providing a separate adhesive layer. However, depending on the manufacturing method, after the transparent resin layer 3 is cured, the transparent substrate 2 can be bonded through an adhesive layer. Also in this case, it is necessary that the entire side surface and bottom surface of the pattern electrode 4 are in contact with the transparent resin layer 3 and the pattern electrode 4 is not in contact with the adhesive layer.

  Next, an embodiment of the transparent electrode substrate manufacturing method of the present invention will be described with reference to FIGS.

  The process flow of one Embodiment of a transparent electrode base material manufacturing method is shown in FIG. The pattern electrode 4 is printed on the surface of the release film 6 (FIG. 6A), the transparent resin layer 3 is formed on the release film 6 and the pattern electrode 4 (FIG. 6B), and the hard coat layer is formed on one side of the resin film 7 8. Laminated transparent substrate 2 with antireflection layer 9 sequentially formed with resin film 7 side inside (FIG. 6C), and in this state, UV is irradiated from light receiving surface 11 side to cure transparent resin layer 3 (FIG. 6D), the release film 6 is removed (FIG. 6E), and the collector electrode 5 is formed on the surfaces of the transparent resin layer 3 and the pattern electrode 4 (FIG. 6F).

  FIG. 7 shows a process flow of another embodiment of the transparent electrode substrate manufacturing method. The pattern electrode 4 is printed on the surface of the release film 6 (FIG. 7A). A transparent resin layer 3 is formed on the side opposite to the antireflection layer of the transparent substrate 2 in which the hard coat layer 8 and the antireflection layer 9 are sequentially formed on one side of the resin film 7 (FIG. 7B). The transparent substrate 2 is laminated with the pattern electrode 4 side and the transparent resin layer 3 side inside, respectively (FIG. 7C). In this state, the transparent resin layer 3 is cured by irradiating UV from the light receiving surface 11 side (FIG. 7D), the release film 6 is removed (FIG. 7E), and the collecting electrode 5 is formed on the surfaces of the transparent resin layer 3 and the pattern electrode 4 (FIG. 7F).

  FIG. 8 shows a process flow of another embodiment of the transparent electrode substrate manufacturing method. The pattern electrode 4 is printed on the surface of the release film 6 (FIG. 8A), and after forming the transparent resin layer 3 on the release film 6 and the pattern electrode 4 (FIG. 8B), the transparent resin layer 3 is cured ( FIG. 8C). A transparent substrate 2 having a hard coat layer 8 and an antireflection layer 9 sequentially formed on one side of the resin film 7 is laminated on the surface of the transparent resin layer 3 with an adhesive layer 10 (FIG. 8D). It removes (FIG. 8E) and forms the current collection electrode 5 on the surface of the transparent resin layer 3 and the pattern electrode 4 (FIG. 8F).

  FIG. 9 shows a process flow of another embodiment of the transparent electrode substrate manufacturing method. The collector electrode 5 is formed on the surface of the release film 6 (FIG. 9A), the pattern electrode 4 is printed on the surface (FIG. 9B), and the transparent resin layer 3 is formed on the collector electrode 5 and the pattern electrode 4 (FIG. 9C) and laminating the transparent base material 2 in which the hard coat layer 8 and the antireflection layer 9 are sequentially formed on one side of the resin film 7 with the resin film 7 side inward (FIG. 9D). The transparent resin layer 3 is cured by irradiating UV from the light receiving surface 11 side (FIG. 9E), and the release film 6 is removed (FIG. 9F).

  According to the method shown in FIGS. 6 to 8, the transparent resin layer 3 is cured in a state where the pattern electrode 4 and the transparent resin layer 3 are in contact with the surface of the release film 6, so that the release film-pattern electrode interface And no step at the release film-transparent resin layer interface, and is less susceptible to shrinkage and the like when the transparent resin layer is cured. Therefore, in the stage before forming the current collecting electrode (FIGS. 6E, 7E, and 8E), there is hardly any step between the transparent resin layer surface and the pattern electrode surface. As a result, on the surface of the transparent electrode 5, a step is hardly generated between a portion formed on the transparent resin layer and a portion formed on the pattern electrode. Moreover, in the method shown in FIG. 9, since the current collection electrode 5 is formed on the surface of the release film 9, a level | step difference does not arise in the surface of a current collection electrode.

  6 to 8, the surface roughness of the transparent resin layer 3 and the pattern electrode 4 before the formation of the collecting electrode 5 (FIGS. 6E, 7E, and 8E) is the surface roughness of the release film 6. Strongly influenced by. As a result, the surface roughness of the collecting electrode is strongly influenced by the surface roughness of the release film. In the method shown in FIG. 9, the surface roughness of the current collecting electrode is directly affected by the surface roughness of the release film. Therefore, it is preferable that the release film has a smaller surface roughness Rz. The surface roughness Rz of the release film is preferably 50 nm or less, and more preferably 20 nm or less.

  In the above method, the method for printing the pattern electrode 4 is not particularly limited, but screen printing is preferable. By using the screen printing method, the cross-sectional shape of the pattern electrode can be easily formed into a bowl shape. Moreover, the pattern electrode containing the metal fine particle and the binder used as a binder can be easily formed by screen-printing the paste containing the conductive fine particle. Further, by using the screen printing method, the product area can be easily increased.

  Moreover, when forming the pattern electrode 4, it is preferable to form so that there may be no pointed part in the opening shape of a pattern electrode. The effect that bubbles remain at the interfaces of the release film 6, the pattern electrode 4, and the transparent resin layer 3 due to the fact that the corners of the opening of the pattern electrode are not sharp and the cross-sectional shape of the pattern electrode is saddle-shaped. Is obtained.

  In order to laminate the release film 6 and the transparent substrate 2, various pressing methods can be used. At that time, since the entire side surface and bottom surface of the pattern electrode 4 excluding the plane portion on the release film side are covered with the transparent resin layer 3, even when the pattern electrode has conductive fine particles, It is difficult for the conductive fine particles to fall off.

  Further, according to the method shown in FIG. 8, in order to cure the transparent resin layer with one surface of the transparent resin layer 3 exposed to the atmosphere (FIG. 8C), when a resin other than the active energy ray curable resin is used. Can be cured quickly. Thereby, the range of selection of the material used for a transparent resin layer spreads. As the adhesive layer 10, for example, a commercially available highly transparent adhesive tape having a thickness of about 25 μm using an acrylic adhesive or the like can be used.

  Next, the above embodiment will be described in more detail based on examples.

Example 1
Example 1 is based on the method shown in FIG.

  A silver paste was printed in a grid shape on the surface of a release film 6 made of a cyclic polyolefin having a thickness of 50 μm by screen printing, and dried at 120 ° C. for 30 minutes to form a pattern electrode 4 (FIG. 6A). The surface roughness Rz of the release film 6 was 18 nm. The printing plate used for printing was a stainless steel 500 mesh. The silver paste contained silver fine particles having an average particle diameter of 1 μm. The formed pattern electrode has a square cross section, a silver grid line width of 46 μm, a thickness of 3 μm, and a pattern (grid) shape of a square lattice with a pitch of 2.0 mm. The curvature radius was 50-60 μm.

Next, an acrylic ultraviolet (UV) curable resin is applied on the release film 6 and the pattern electrode 4 to form a transparent resin layer 3 (FIG. 6B), and hardened on one side of a 125 μm thick PET film 7. The transparent base material 2 on which the coating layer 8 and the antireflection layer 9 were sequentially formed was laminated with the PET film 7 side inside (FIG. 6C). In this state, the transparent resin layer 3 was cured by irradiating UV from the light receiving surface 11 side (FIG. 6D). UV irradiation was performed using a high-pressure mercury lamp, and the integrated irradiation light amount calculated based on the measurement value of a UV photometer (Nihon Batteries Co., Ltd., UV-350N) was 500 mJ / cm ² . The film thickness of the transparent resin layer 3 after UV curing was 8 μm.

  Next, after removing the release film 6 (FIG. 6E), an ITO thin film was formed as a collecting electrode 5 on the surfaces of the transparent resin layer 3 and the pattern electrode 4 (FIG. 6F). The ITO thin film was formed by sputtering in an Ar / O2 atmosphere using an ITO target, and the thickness was 30 nm. The transparent electrode base material 1 was obtained by the above process.

(Example 2)
In Example 2, a transparent electrode substrate was produced by the same method and conditions as Example 1 except that the width of the grid line of the pattern electrode was 95 μm and the grid shape was a pitch of 5.3 mm.

(Example 3)
Example 3 is based on the method shown in FIG. However, a transparent substrate having no hard coat layer and antireflection film was used.

  On the surface of the release film 6 made of cyclic polyolefin, a silver paste was printed in a grid shape by screen printing and dried to form a pattern electrode 4 (FIG. 7A). The materials used, printing and firing conditions, and the shape of the pattern electrode are all the same as in Example 1.

  Next, a PET film 7 having a thickness of 125 μm (the hard coat layer 8 and the antireflection layer 9 are not provided) is used as the transparent base material 2, and the same UV curable resin as in Example 1 is applied to the surface (FIG. 7B). A transparent substrate 2 was laminated thereon with the pattern electrode side inside (FIG. 7C). In this state, the transparent resin layer 3 was cured by irradiating UV from the light receiving surface 11 side (FIG. 7D). The UV irradiation conditions and the thickness of the transparent resin layer 3 after UV curing were the same as in Example 1.

  Next, after removing the release film 6 (FIG. 7E), an ITO thin film was formed as a collecting electrode 5 on the surfaces of the transparent resin layer 3 and the pattern electrode 4 (FIG. 7F). The ITO film formation conditions and film thickness were the same as in Example 1.

Example 4
Example 4 is based on the method shown in FIG. A transparent electrode substrate was prepared by the same method and conditions as in Example 1 except that an acrylic urethane-based UV curable resin was used for the transparent resin layer and the thickness of the transparent resin layer after UV curing was 15 μm. Produced.

  Table 1 shows the production conditions of Examples 1 to 4 and the characteristics of the obtained transparent electrode substrate. The total light transmittance was measured by the above-mentioned method using a haze meter (Nippon Denshoku Industries Co., Ltd., NDH2000). The surface resistance was measured by the above-described method using a resistivity meter (Mitsubishi Chemical Analytech Co., Ltd., Loresta GP / MCP-T610). The surface roughness Rz in the table is divided into a portion formed on the transparent resin layer and a portion formed on the pattern electrode on the surface of the current collecting electrode. Further, the step means a step between a portion formed on the pattern electrode and a portion formed on the transparent resin layer on the surface of the collecting electrode. The surface roughness Rz of the current collecting electrode and the level difference were measured using a level difference / surface roughness / fine shape measuring apparatus (KLA-Tencor Corporation, P-6). The definition of Rz is in accordance with JISB0601-2001, and the level difference is obtained from a wavy curve in the same standard.

  As can be seen from Table 1, in any of Examples 1 to 4, a transparent electrode substrate having a high total light transmittance, a low surface resistance, and a flat collector electrode surface was obtained.

  10 and 11 show a scanning electron microscope (SEM) photograph of a cross section of the transparent electrode substrate of Example 1. FIG. FIG. 11 is an enlarged view of a part of FIG. Since the current collecting electrode layer 5 is thin, it cannot be confirmed by an SEM photograph. As can be seen from FIG. 10, the pattern electrode 4 has a saddle-shaped cross section. In FIG. 10, the boundary between the transparent base material 2 and the transparent resin layer 3 appears to wave, but this is due to the end of the transparent base material 2 being turned up during sample preparation. From FIG. 11, it can be confirmed that the pattern electrode 4 contains particulate silver. Further, in FIG. 11, a slightly white portion is seen along the outline of the silver fine particles, which is a portion where the organic matter remains.

DESCRIPTION OF SYMBOLS 1 Transparent resin substrate 2, 2 'transparent base material 3 Transparent resin layer 4 Pattern electrode 5 Current collecting electrode 6 Release film 7 Resin film 8 Hard coat layer 9 Antireflection layer 10 Adhesive layer 11, 11' Light-receiving surface 13 Current collecting electrode -Transparent resin layer interface 14 Current collecting electrode-Pattern electrode interface 15 Current collecting electrode surface 16 Pattern electrode opening 17 Corner angle of pattern electrode opening 23 Average roughness of transparent resin layer interface (10-point average roughness Rz)
24 Average roughness of pattern electrode interface (10-point average roughness Rz)
25 Step between transparent resin layer and pattern electrode at electrode interface 31 Organic thin film solar cell (OPV)
33 Transparent electrode 35 Hole transport layer 36 Active layer 37 Electron transport layer 38 Aluminum electrode

Claims (12)

A plate-shaped transparent substrate;
A transparent resin layer formed on one side of the transparent substrate;
A pattern electrode embedded in a surface of the transparent resin layer opposite to the transparent substrate;
A transparent current collecting electrode formed directly on the transparent resin layer and the pattern electrode;
The surface of the said current collection electrode is flat, The transparent electrode base material characterized by the above-mentioned. The transparent electrode substrate according to claim 1, wherein a cross-sectional shape of the pattern electrode is a bowl shape. The transparent electrode substrate according to claim 1, wherein the pattern electrode includes metal particles. The said pattern electrode has silver as a main component, The transparent electrode base material as described in any one of Claims 1-3 characterized by the above-mentioned. On the surface of the current collecting electrode, the level difference between the portion formed on the pattern electrode and the portion formed on the transparent resin layer is the surface roughness Rz of the surface on the current collecting electrode on the pattern electrode. The transparent electrode substrate according to any one of claims 1 to 4, wherein the transparent electrode substrate has a surface roughness Rz or less of a portion on the transparent resin layer on the surface of the collecting electrode. The surface roughness Rz of the part on the said transparent resin layer of the said collector electrode surface is 100 nm or less, The transparent electrode base material as described in any one of Claims 1-5 characterized by the above-mentioned. In the surface of the current collecting electrode, the surface roughness Rz of the portion where the current collecting electrode is formed on the pattern electrode is equal to or greater than the surface roughness Rz of the portion formed on the transparent resin layer. The transparent electrode base material as described in any one of Claims 1-6. Printing the pattern electrode on the surface of the release film;
Forming a transparent resin layer on the surface of the release film and the pattern electrode;
Laminating a transparent substrate on the transparent resin layer;
Peeling the release film;
The method of manufacturing the transparent electrode base material as described in any one of Claims 1-7 which has a process of forming a transparent current collection electrode in the surface of the said transparent resin layer and the pattern electrode embedded in the surface. Printing the pattern electrode on the surface of the release film;
Forming a transparent resin layer on the transparent substrate;
Laminating the release film on the surface of the transparent resin layer with the pattern electrode side inside;
Curing the transparent resin layer;
Peeling the release film;
The method of manufacturing the transparent electrode base material as described in any one of Claims 1-7 which has a process of forming a transparent current collection electrode in the surface of the said transparent resin layer and the pattern electrode embedded in the surface. Forming a transparent current collecting electrode on the surface of the release film;
Printing a pattern electrode on the surface of the current collecting electrode;
Forming a transparent resin layer on the surface of the release film and the pattern electrode;
Laminating a transparent substrate on the transparent resin layer;
The method of manufacturing the transparent electrode base material as described in any one of Claims 1-7 which has the process of peeling the said release film. The method for producing a transparent electrode substrate according to any one of claims 8 to 10, wherein the step of printing the pattern electrode is a step of screen printing a paste containing metal particles. The surface roughness Rz of the said release film is 50 nm or less, The transparent electrode base material manufacturing method as described in any one of Claims 8-11 characterized by the above-mentioned.