JP5326731B2 - Organic thin film solar cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic thin film solar cell which hardly short-circuits between electrodes and has excellent photoelectric conversion efficiency even when having large area. <P>SOLUTION: The organic thin film solar cell includes a transparent substrate, an inside auxiliary electrode formed in a pattern shape on one surface of the transparent substrate, a transparent electrode formed on the inside auxiliary electrode, a photoelectric conversion layer formed on the transparent electrode, a counter electrode formed on the photoelectric conversion layer, an outside auxiliary electrode formed in a pattern shape on the other surface of the transparent substrate and having a smaller resistance value than the transparent electrode, a connecting conduction portion penetrating the transparent electrode to electrically connect the outside auxiliary electrode and inside auxiliary electrode to each other, and an optical member formed on the outside auxiliary electrode to guide light made incident on a light shield region where the outside auxiliary electrode and inside auxiliary electrode are provided to the photoelectric conversion layer. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an organic thin film solar cell capable of increasing the area.

  An organic thin film solar cell is a solar cell in which an organic thin film having an electron donating function and an electron accepting function is disposed between two different electrodes, and a manufacturing process compared to an inorganic solar cell typified by silicon or the like. Is easy, and has the advantage that the area can be increased at low cost.

  In the solar cell, the electrode on the light receiving side is a transparent electrode. Conventionally, metal oxides such as ITO have been used for this transparent electrode, and ITO is mainly used because of its high conductivity and transparency and high work function. However, since the ITO electrode used in the organic thin film solar cell is as thin as about 150 nm and the sheet resistance is as large as about 20 Ω / □, the generated current is consumed when passing through the ITO electrode, and the power generation efficiency is lowered. There is a problem. This phenomenon becomes more prominent as the area of the organic thin film solar cell increases.

  In recent years, in order to improve the electroconductivity of an electrode, it is proposed to laminate | stack a metal mesh on a transparent electrode in a silicon solar cell or a dye-sensitized solar cell (for example, refer patent documents 1-3). However, since the metal mesh blocks light, there is a problem that the amount of incident light is reduced by laminating the metal mesh on the transparent electrode, resulting in a decrease in power generation efficiency. Therefore, it has been proposed to arrange light guide means such as a convex lens on the light receiving surface side of the transparent substrate (see Patent Document 4).

Japanese Patent Laid-Open No. 2000-243998 JP 2000-243990 A JP 2007-78909 A JP 2003-346927 A

In an organic thin film solar cell, it is conceivable to laminate a metal mesh on a transparent electrode in order to improve power generation efficiency.
However, the thickness of the metal mesh used for a silicon solar cell or a dye-sensitized solar cell is as very thick as about 2 micrometers-20 micrometers. On the other hand, in an organic thin film solar cell, the thickness of an organic layer such as a photoelectric conversion layer is very thin, 100 nm to 200 nm. Therefore, when the metal mesh used for silicon solar cells and dye-sensitized solar cells is applied as it is to organic thin-film solar cells, the thickness of the organic layers such as the photoelectric conversion layer is thin. There is a problem that it is difficult to uniformly coat, and as a result, a short circuit occurs between the electrodes.

  The present invention has been made in view of the above problems, and it is a main object of the present invention to provide an organic thin-film solar cell that is less likely to be short-circuited between electrodes and that has good photoelectric conversion efficiency even in a large area. .

  To achieve the above object, the present invention provides a transparent substrate, an inner auxiliary electrode formed in a pattern on one surface of the transparent substrate, a transparent electrode formed on the inner auxiliary electrode, and the transparent A photoelectric conversion layer formed on the electrode; a counter electrode formed on the photoelectric conversion layer; an outer auxiliary electrode formed in a pattern on the other surface of the transparent substrate and having a lower resistance than the transparent electrode; A conductive connecting portion that penetrates the transparent substrate and electrically connects the outer auxiliary electrode and the inner auxiliary electrode; and is formed on the outer auxiliary electrode, and the outer auxiliary electrode and the inner auxiliary electrode are provided. An organic thin-film solar cell comprising: an optical member that guides light incident on a light shielding region to the photoelectric conversion layer.

  According to the present invention, since the outer auxiliary electrode, the inner auxiliary electrode, and the transparent electrode are electrically connected by the connection conductive portion, even if the sheet resistance of the transparent electrode is relatively high, the resistance value of the outer auxiliary electrode is If it is sufficiently low, the resistance of the entire electrode can be made sufficiently low. Therefore, even if the organic thin-film solar cell of this invention is a large area, it becomes possible to collect the generated electric power efficiently. According to the present invention, since the thickness of the outer auxiliary electrode does not affect the short circuit between the electrodes, the thickness can be made relatively thick, the line width can be made relatively small, and the opening area can be made large. Thus, it is possible to obtain a solar cell having excellent daylighting performance and a high current collecting function without causing a short circuit. Furthermore, according to the present invention, since the optical member is formed on the light receiving surface side of the transparent substrate, the light can be efficiently incident on the photoelectric conversion layer by the action of light convergence, divergence, refraction, and the like of the optical member. it can. Therefore, in the present invention, high power generation efficiency can be obtained.

  The present invention also includes a transparent substrate, a transparent electrode formed on one surface of the transparent substrate, a photoelectric conversion layer formed on the transparent electrode, and a counter electrode formed on the photoelectric conversion layer. The outer auxiliary electrode having a pattern formed on the other surface of the transparent substrate and having a resistance value lower than that of the transparent electrode and the connection penetrating the transparent substrate and electrically connecting the outer auxiliary electrode and the transparent electrode An organic thin-film solar cell comprising: a conductive portion; and an optical member that is formed on the outer auxiliary electrode and guides light incident on a light shielding region provided with the outer auxiliary electrode to the photoelectric conversion layer. provide.

  According to the present invention, since the outer auxiliary electrode and the transparent electrode are electrically connected by the connection conductive portion, even if the sheet resistance of the transparent electrode is relatively high, if the resistance value of the outer auxiliary electrode is sufficiently low The resistance of the entire electrode can be made sufficiently low. Therefore, even if the organic thin-film solar cell of this invention is a large area, it becomes possible to collect the generated electric power efficiently. Further, according to the present invention, since the thickness of the outer auxiliary electrode does not affect the short circuit between the electrodes, the thickness can be made relatively thick, the line width can be made relatively small, and the opening area can be made large, and In addition, since a patterned auxiliary electrode is not formed between the transparent substrate and the photoelectric conversion layer, a short circuit between the electrodes does not occur, and it is possible to obtain a solar cell with excellent daylighting and a high current collecting function. It is. Furthermore, according to the present invention, since the optical member is formed on the light receiving surface side of the transparent substrate, the light can be efficiently incident on the photoelectric conversion layer by the action of light convergence, divergence, refraction, and the like of the optical member. it can. Therefore, in the present invention, high power generation efficiency can be obtained.

  Furthermore, the present invention provides a transparent substrate, a transparent electrode and a patterned inner auxiliary electrode laminated in random order on one surface of the transparent substrate, and a photoelectric conversion layer formed on the transparent electrode and the inner auxiliary electrode. A counter electrode formed on the photoelectric conversion layer, and an optical member that is formed on the other surface of the transparent substrate and guides the light incident on the light shielding region provided with the inner auxiliary electrode to the photoelectric conversion layer And the inner auxiliary electrode has a thickness that does not cause a short circuit between the transparent electrode, the inner auxiliary electrode, and the counter electrode.

  According to the present invention, the anode side electrode is formed by laminating the inner auxiliary electrode and the transparent electrode. Therefore, even if the sheet resistance of the transparent electrode is relatively high, the resistance value of the inner auxiliary electrode is sufficiently low. The sheet resistance of the whole anode can be sufficiently lowered. Therefore, even if the organic thin film solar cell of the present invention has a large area, the generated power can be collected efficiently. Moreover, according to this invention, since the thickness of an inner side auxiliary electrode is a thickness which does not produce a short circuit between an inner side auxiliary electrode and a transparent electrode, and a counter electrode, the short circuit between electrodes can be prevented. Furthermore, according to the present invention, since the optical member is formed on the light receiving surface side of the transparent substrate, the light can be efficiently incident on the photoelectric conversion layer by the action of light convergence, divergence, refraction, and the like of the optical member. it can. Therefore, in the present invention, high power generation efficiency can be obtained.

  In the above-described invention, the optical member is preferably a lens member. When a convex lens is used as the optical member, it is possible to collect a large amount of light at the opening of the patterned auxiliary electrode, which is the power generation unit, and the amount of power generation in the portion that is blocked by the patterned auxiliary electrode and cannot contribute to power generation Can be compensated by condensing. As a result, the amount of power generated by the solar cell can be assured as that of a solar cell that does not have a pattern-shaped auxiliary electrode, or equal to or greater than that. In addition, when a concave lens is used as an optical member, the surface area of the light incident surface can be made larger than that of a flat transparent substrate, and a pattern that becomes a light-shielding region by optimally designing the thickness of the transparent substrate and the concave lens. It becomes possible to irradiate light on the lower side of the auxiliary electrode. As a result, the amount of power generated by the solar cell can be assured as that of a solar cell that does not have a pattern-like auxiliary electrode, or equal to or greater than that.

  In the present invention, the pattern shape of the auxiliary electrode is preferably a mesh shape. This is because the resistance value of the auxiliary electrode can be further reduced.

  Furthermore, in the said invention, it is preferable that the thickness of the said inner side auxiliary electrode exists in the range of 10 nm-1000 nm. This is because if the inner auxiliary electrode is too thick, a short circuit may occur between the electrodes.

  In this case, it is preferable that the inner auxiliary electrode and the transparent electrode are sequentially laminated on the transparent substrate. This is because the larger the contact area between the transparent electrode and the photoelectric conversion layer, the hole extraction layer, or the like, the better the interface bondability.

  Further, the transparent electrode and the inner auxiliary electrode may be laminated in this order on the transparent substrate.

  In the present invention, it is possible to prevent the occurrence of a short circuit between the electrodes, and even if an auxiliary electrode is formed, it is possible to suppress a significant decrease in the amount of light incident on the photoelectric conversion layer. Even if the area is increased, there is an effect that high power generation efficiency can be obtained.

It is a schematic sectional drawing which shows an example of the organic thin film solar cell of this invention. It is a schematic sectional drawing which shows the other example of the organic thin film solar cell of this invention. It is a schematic sectional drawing which shows the other example of the organic thin film solar cell of this invention. It is a schematic sectional drawing which shows the other example of the organic thin film solar cell of this invention. It is a schematic sectional drawing which shows the other example of the organic thin film solar cell of this invention. It is a schematic sectional drawing which shows the other example of the organic thin film solar cell of this invention. It is a schematic diagram which shows an example of the outer side auxiliary electrode and inner side auxiliary electrode in the organic thin-film solar cell of this invention. It is a schematic diagram which shows the other example of the outer side auxiliary electrode and inner side auxiliary electrode in the organic thin-film solar cell of this invention. It is process drawing which shows an example of the manufacturing method of the organic thin film solar cell of this invention. It is process drawing which shows the other example of the manufacturing method of the organic thin film solar cell of this invention. It is process drawing which shows the other example of the manufacturing method of the organic thin film solar cell of this invention. It is process drawing which shows the other example of the manufacturing method of the organic thin film solar cell of this invention. It is a schematic sectional drawing which shows the other example of the organic thin film solar cell of this invention. It is process drawing which shows the other example of the manufacturing method of the organic thin film solar cell of this invention. It is process drawing which shows the other example of the manufacturing method of the organic thin film solar cell of this invention. It is process drawing which shows the other example of the manufacturing method of the organic thin film solar cell of this invention. It is process drawing which shows the other example of the manufacturing method of the organic thin film solar cell of this invention. It is a schematic sectional drawing which shows the other example of the organic thin film solar cell of this invention. It is a schematic sectional drawing which shows the other example of the organic thin film solar cell of this invention.

Hereinafter, the organic thin film solar cell of the present invention will be described in detail.
The organic thin film solar cell of the present invention can be divided into three embodiments according to the configuration of the auxiliary electrode. In the following, each embodiment will be described separately.

I. First Embodiment A first embodiment of the organic thin-film solar cell of the present invention is formed on a transparent substrate, an inner auxiliary electrode formed in a pattern on one surface of the transparent substrate, and the inner auxiliary electrode. A transparent electrode, a photoelectric conversion layer formed on the transparent electrode, a counter electrode formed on the photoelectric conversion layer, and formed in a pattern on the other surface of the transparent substrate, and has a resistance value higher than that of the transparent electrode. A low outer auxiliary electrode, a connection conductive portion that penetrates the transparent substrate and electrically connects the outer auxiliary electrode and the inner auxiliary electrode, and is formed on the outer auxiliary electrode, and the outer auxiliary electrode and the inner auxiliary electrode are formed on the outer auxiliary electrode. And an optical member for guiding light incident on the light shielding region provided with the auxiliary electrode to the photoelectric conversion layer.

The organic thin film solar cell of this embodiment will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of an organic thin film solar cell of this embodiment. In the example shown in FIG. 1, the organic thin film solar cell 1 includes a transparent substrate 2, an inner auxiliary electrode 3 formed in a mesh shape on one surface of the transparent substrate 2, and a transparent electrode formed on the inner auxiliary electrode 3. 4, a hole extraction layer 5 formed on the transparent electrode 4, a photoelectric conversion layer 6 formed on the hole extraction layer 5, a counter electrode 7 formed on the photoelectric conversion layer 6, and a transparent substrate 2 is formed in a mesh shape on the other surface, and has a lower resistance value than the transparent electrode 4 and a connection that penetrates the transparent substrate 2 and electrically connects the outer auxiliary electrode 8 and the inner auxiliary electrode 3. It has a conductive portion 9 and a convex lens 11 a that is formed on the outer auxiliary electrode 8 and guides light incident on the light shielding region 10 provided with the outer auxiliary electrode 8 and the inner auxiliary electrode 3 to the photoelectric conversion layer 6. .

The inner auxiliary electrode and the transparent electrode are formed on one surface of the transparent substrate, and the outer auxiliary electrode is formed on the other surface of the transparent substrate. The inner auxiliary electrode and the transparent electrode of the transparent substrate are formed. It means that the outer auxiliary electrode is formed on the surface opposite to the surface on which it is present.
Further, the light shielding region refers to a region where the outer auxiliary electrode and the inner auxiliary electrode are provided.

  In the organic thin-film solar cell 1 illustrated in FIG. 1, first, incident light L is incident on the convex lens 11 a and is condensed by the light converging action of the convex lens 11, and the transparent substrate 2, the transparent electrode 4, and the hole extraction layer 5. And enters the photoelectric conversion layer 6. At this time, the light L incident on the convex lens 11 a in the light shielding region 10 is collected by the converging action of the light of the convex lens, so that it is efficiently applied to the photoelectric conversion layer 6 without being blocked by the outer auxiliary electrode 8 and the inner auxiliary electrode 3. Can be incident. Then, charges (holes and electrons) are generated in the photoelectric conversion layer 6 by the incident light L. Next, the generated charges (holes) move in the film thickness direction of the photoelectric conversion layer 6 and are extracted to the hole extraction layer 5, and the transparent electrode 4 is contacted at the contact interface between the hole extraction layer 5 and the transparent electrode 4. It is taken out. On the other hand, the generated charges (electrons) move in the film thickness direction of the photoelectric conversion layer 6 and are taken out to the counter electrode 7 at the contact interface between the photoelectric conversion layer 6 and the counter electrode 7.

FIG. 2 is a schematic cross-sectional view showing another example of the organic thin film solar cell of this embodiment. An organic thin film solar cell 1 shown in FIG. 2 is obtained by forming a concave lens 11b in place of the convex lens 11a in the organic thin film solar cell 1 shown in FIG.
In the organic thin film solar cell 1 illustrated in FIG. 2, first, the incident light L is incident on the concave lens 11 b and is diffused by the diverging action of the light of the concave lens to form the transparent substrate 2, the transparent electrode 4, and the hole extraction layer 5. The light passes through and enters the photoelectric conversion layer 6. At this time, the light L incident on the concave lens 11b in the light shielding region 10 is diffused by the diverging action of the light of the concave lens, so that the photoelectric conversion layer 6 is efficiently blocked without being blocked by the outer auxiliary electrode 8 and the inner auxiliary electrode 3. Can be incident.

FIG. 3 is a schematic cross-sectional view showing another example of the organic thin film solar cell of this embodiment. The organic thin film solar cell 1 shown in FIG. 3 is obtained by forming a prism 11c in place of the convex lens 11a in the organic thin film solar cell 1 shown in FIG.
In the organic thin film solar cell 1 illustrated in FIG. 3, first, incident light L is incident on the prism 11 c, and the light traveling direction is bent by the light dispersion and refraction action of the prism, so that the transparent substrate 2 and the transparent electrode 4. Then, the light passes through the hole extraction layer 5 and enters the photoelectric conversion layer 6. At this time, the light L incident on the prism 11 c in the light shielding region 10 is bent in the traveling direction by the light dispersion / refractive action of the prism, so that the photoelectric conversion is not interrupted by the outer auxiliary electrode 8 and the inner auxiliary electrode 3. It can efficiently enter the layer 6.

  As described above, according to this embodiment, since the optical member that guides the light incident on the light shielding region such as the convex lens, the concave lens, and the prism to the photoelectric conversion layer is formed, the outer auxiliary electrode and the inner auxiliary electrode are formed. However, efficient power generation is possible without significantly reducing the amount of incident light.

  Further, according to this embodiment, the outer auxiliary electrode and the inner auxiliary electrode are electrically connected by the connection conductive portion, and the anode side electrode is composed of the outer auxiliary electrode, the inner auxiliary electrode, and the transparent electrode. Even when the sheet resistance of the transparent electrode is relatively high, the resistance of the whole anode can be reduced. That is, the generated power can be efficiently collected by the outer auxiliary electrode. Therefore, even if the organic thin-film solar cell is increased in area, it is possible to maintain high power generation efficiency.

  Furthermore, according to this embodiment, since the outer auxiliary electrode is formed on the light receiving surface side of the transparent substrate, the thickness of the outer auxiliary electrode does not affect the short circuit between the electrodes. Therefore, the outer auxiliary electrode can be made relatively thick. Therefore, by adjusting the aperture ratio and thickness of the outer auxiliary electrode, it is possible to control the resistance of the anode as a whole while ensuring a large aperture ratio.

Moreover, since the inner auxiliary electrode and the transparent electrode are laminated on the transparent substrate, it is possible to improve the bonding at the interface between the connection conductive portion, the inner auxiliary electrode, and the transparent electrode.
Hereinafter, each structure in the organic thin-film solar cell of this embodiment is demonstrated.

1. Optical member The optical member used in this embodiment is formed on the outer auxiliary electrode, and guides the light incident on the light shielding region where the outer auxiliary electrode and the inner auxiliary electrode are provided to the photoelectric conversion layer.

  The optical member is not particularly limited as long as it can guide the light incident on the light shielding region to the photoelectric conversion layer. For example, a convex lens, a concave lens, a prism, an antireflection film, or the like can be used. Among these, lens members such as a convex lens and a concave lens are preferable. This is because the control of irradiating sunlight, which is parallel light, to an appropriate location is the easiest by designing the lens member appropriately. For example, when a convex lens is provided, it is possible to collect a large amount of light at the openings of the patterned outer auxiliary electrode and inner auxiliary electrode, which are power generation units, and the light is blocked by the patterned outer auxiliary electrode and inner auxiliary electrode. Therefore, the amount of power generation that cannot contribute to power generation can be supplemented by condensing light. As a result, the amount of power generated by the solar cell can be assured as that of a solar cell that does not have a pattern-shaped auxiliary electrode, or equal to or greater than that. In addition, when a concave lens is provided, the surface area of the light incident surface can be increased compared to a flat transparent substrate, and the thickness of the transparent substrate and the concave lens can be optimally designed so that the inner side of the pattern that becomes the light shielding region Light can be irradiated to the lower side of the auxiliary electrode. As a result, the amount of power generated by the solar cell can be assured as that of a solar cell that does not have the patterned outer auxiliary electrode and the inner auxiliary electrode, or equal to or higher than that.

  In particular, the optical member is preferably capable of guiding light to the photoelectric conversion layer in the light shielding region. Here, the photoelectric conversion layer is an insulator when light is not irradiated, and becomes a conductor when light is irradiated. Therefore, when there are a portion irradiated with light and a portion not irradiated with light, the portion irradiated with light becomes a conductor, and the portion not irradiated with light remains an insulator. Therefore, in order to improve power generation efficiency, it is preferable that the number of portions not irradiated with light is as small as possible. When the optical member is not provided, it becomes difficult for light to enter the photoelectric conversion layer in the light shielding region. Therefore, an optical member that can guide light to the photoelectric conversion layer in the light shielding region is preferable.

  As such an optical member, a convex lens and a concave lens are preferable, and among them, a concave lens is preferably used. When the light is collected by the convex lens and the incident light per unit area is amplified, the solar cell element is heated by sunlight and the temperature of the solar cell element is greatly increased, which may cause damage to the solar cell element. Therefore, it is preferable to diffract light with a concave lens.

  The arrangement of the optical member only needs to be able to guide the light incident on the light shielding region to the photoelectric conversion layer, and is appropriately selected according to the type of the optical member and the pattern shape of the outer auxiliary electrode and the inner auxiliary electrode.

For example, when the optical member is a convex lens or a concave lens, the convex lens and the concave lens are disposed so that the ends of the convex lens 11a and the concave lens 11b are positioned in the light shielding region 10 as illustrated in FIGS. preferable. This is because light incident on the convex lens and the concave lens in the light shielding region can be efficiently guided to the photoelectric conversion layer.
Further, when the optical member is a convex lens or a concave lens, and the pattern shape of the outer auxiliary electrode and the inner auxiliary electrode is a hexagonal lattice shape (honeycomb shape), the optical member is a convex lens and a concave lens having a honeycomb shape. It is preferable that the lens array is arranged in the same manner. This is because with such a lens array, the end portions of the convex lens and the concave lens can be positioned in the light shielding region 10.
When the optical member is a convex lens or a concave lens, and the pattern shape of the outer auxiliary electrode and the inner auxiliary electrode is a square lattice shape, for example, the lens shape should be circumscribed to the rectangular opening. Can do.

  On the other hand, for example, when the optical member is a prism, it is preferable that the prism 11c is arranged only in the light shielding region 10 as illustrated in FIG. This is because light incident on the light shielding region can be efficiently guided to the photoelectric conversion layer.

  The diameter, pitch, curvature and the like of the convex lens and the concave lens are appropriately adjusted according to the diameter and pitch of the openings of the outer auxiliary electrode and the inner auxiliary electrode, the line widths of the outer auxiliary electrode and the inner auxiliary electrode, and the like. In addition, the width, height, and the like of the prism are appropriately adjusted according to the line widths of the outer auxiliary electrode and the inner auxiliary electrode.

  As a material constituting the convex lens, concave lens, prism and the like, a resin is usually used. As resin, what is generally used as a forming material of a convex lens, a concave lens, and a prism is employable.

  Examples of a method for forming a convex lens, a concave lens, a prism, and the like include a method using a mold.

2. Connection conductive part The connection conductive part used in this embodiment penetrates the transparent substrate and electrically connects the outer auxiliary electrode and the inner auxiliary electrode.

  A metal is usually used as a material for forming the connection conductive portion. Examples of the metal used for the connection conductive portion include aluminum (Al), gold (Au), silver (Ag), cobalt (Co), nickel (Ni), platinum (Pt), copper (Cu), and aluminum alloy. Can be mentioned.

The shape of the connection conductive portion is not particularly limited as long as it is a shape that penetrates the transparent substrate, and may be, for example, a columnar shape or a conical shape.
When the connection conductive part is derived from a conductive bump (projection) formed on the metal foil, the shape of the connection conductive part changes in diameter in the thickness direction depending on the process of forming the conductive bump. It becomes a conical shape. In this case, as illustrated in FIG. 4, the shape of the connection conductive portion 9 is preferably a conical shape having a small diameter on the inner auxiliary electrode 3 side and a larger diameter on the outer auxiliary electrode 8 side. This is because the outer auxiliary electrode can be formed by patterning the metal foil on which the conductive bumps are formed.

The connection conductive part 9 may be formed so as to fill all the through holes provided in the transparent substrate 2 as illustrated in FIGS. 1 to 4, and is provided in the transparent substrate 2 as illustrated in FIG. 5. It may be formed so as to cover the wall surface of the through hole.
As illustrated in FIG. 5, when the connection conductive portion 9 is formed so as to cover the wall surface of the through hole provided in the transparent substrate 2, the portion other than the wall surface of the through hole is filled with, for example, resin 12 or the like. Preferably it is. When forming a metal thin film on the entire surface of the transparent substrate by a vapor deposition method such as sputtering to form the inner auxiliary electrode, if the resin is not filled, the metal thin film forming material will pass through the holes. This is because it becomes difficult to form a metal thin film on the entire surface of the transparent substrate.
Especially, it is preferable that the connection electroconductive part is formed so that all the through-holes provided in the transparent substrate may be filled. This is because the conductivity can be increased.

  The connecting conductive portion may be formed so that the outer auxiliary electrode and the inner auxiliary electrode are electrically connected by the connecting conductive portion. Among them, the connection conductive part, the outer auxiliary electrode and the inner auxiliary electrode themselves basically do not transmit light, and light enters the photoelectric conversion layer from the openings of the outer auxiliary electrode and the inner auxiliary electrode. In order to secure a sufficient amount of light, it is preferable that the connection conductive portion is disposed in a region where the outer auxiliary electrode and the inner auxiliary electrode are provided.

  Moreover, since the connection conductive part should just electrically connect the outer auxiliary electrode and the inner auxiliary electrode, the density of the connection conductive part is usually smaller than the density of the outer auxiliary electrode and the inner auxiliary electrode. The density of the connection conductive portion is appropriately selected according to a desired resistance value, the diameter of the connection conductive portion, and the like.

  The diameter of the connection conductive portion is appropriately set according to the line widths of the outer auxiliary electrode and the inner auxiliary electrode in order to ensure a sufficient amount of light incident on the photoelectric conversion layer.

  As a method for forming the connection conductive part, for example, a method of forming a connection conductive part penetrating the transparent substrate by forming a through hole in the transparent substrate and filling the through hole with a conductive paste, and conducting on the metal foil A method is used in which a conductive bump is formed, a transparent substrate is laminated on the surface of the metal foil on which the conductive bump is formed, the conductive bump is passed through the transparent substrate, and a connection conductive portion that penetrates the transparent substrate is formed. be able to. In addition, since the formation method of a connection conductive part is described in detail in the section of “12. Manufacturing method of organic thin film solar cell” described later, description thereof is omitted here.

3. Outer Auxiliary Electrode The outer auxiliary electrode used in the present embodiment is formed in a pattern on the other surface of the transparent substrate, and has a lower resistance value than the transparent electrode.

  A metal is usually used as a material for forming the outer auxiliary electrode. Examples of the metal used for the outer auxiliary electrode include aluminum (Al), gold (Au), silver (Ag), cobalt (Co), nickel (Ni), platinum (Pt), copper (Cu), an aluminum alloy, Examples thereof include conductive metals such as stainless steel, iron (Fe), and iron-nickel alloy. Among these conductive metals, those having a relatively low electrical resistance value are preferable. Examples of such a conductive metal include Al, Au, Ag, and Cu.

  A preferable metal may be selected according to the work function of the material for forming the counter electrode. For example, when considering the work function of the material for forming the counter electrode, the transparent electrode is a hole extraction electrode, and therefore, the metal used for the outer auxiliary electrode preferably has a high work function. Specifically, Al is preferably used.

  The outer auxiliary electrode may be a single layer or may be composed of a plurality of layers. For example, when conductive bumps (projections) that form connection conductive parts are formed on a metal foil, the conductive bumps are pressed against a transparent substrate to penetrate, and the metal foil on which the conductive bumps are formed is patterned. The outer auxiliary electrode is a single layer derived from the metal foil. Further, for example, when the conductive pattern is plated after the metal thin film is patterned, the outer auxiliary electrode is composed of the conductive pattern and the plating layer.

  When the outer auxiliary electrode is composed of the outer auxiliary electrode conductive pattern and the plating layer, the outer auxiliary electrode conductive pattern may be a single layer made of the above-described conductive metal, and has an adhesion strength to the transparent substrate. In order to ensure, a contact layer may be laminated on the transparent substrate side of the conductive metal layer. Examples of the metal used for the contact layer include nickel (Ni), chromium (Cr), titanium (Ti), and tantalum (Ta).

  The pattern shape of the outer auxiliary electrode is not particularly limited as long as it is a pattern having an opening, and is appropriately selected depending on desired conductivity, permeability, strength, and the like. For example, a mesh shape such as a polygonal shape or a circular lattice shape, a stripe shape, a comb tooth shape, and the like can be given. Among these, a mesh shape is preferable. This is because the resistance value of the outer auxiliary electrode can be further reduced.

  The outer auxiliary electrode and the inner auxiliary electrode itself basically do not transmit light, and light enters the photoelectric conversion layer from the openings of the outer auxiliary electrode and the inner auxiliary electrode. In order to ensure a sufficient amount of light incident on the layer, the outer auxiliary electrode is preferably disposed in a region where the inner auxiliary electrode is provided.

  The thickness of the outer auxiliary electrode does not affect the short circuit between the electrodes and can be made relatively thick. On the other hand, the thickness of the inner auxiliary electrode affects the short circuit between the electrodes and is preferably relatively thin. Therefore, when the outer auxiliary electrode is disposed in a region where the inner auxiliary electrode is provided, the density of the outer auxiliary electrode may be smaller than the density of the inner auxiliary electrode. That is, as illustrated in FIG. 6, the outer auxiliary electrode 8 may be disposed in a region where the inner auxiliary electrode 3 is provided, and may be formed more coarsely than the inner auxiliary electrode 3. In this case, for example, as shown in FIGS. 7A and 7B, when the inner auxiliary electrode 3 has a hexagonal lattice shape (honeycomb shape), the outer auxiliary electrode 8 has a shape shown in FIG. ) Or a lattice shape as shown in FIG. 7B. Further, for example, as shown in FIGS. 8A and 8B, when the shape of the inner auxiliary electrode 3 is a square lattice, the shape of the outer auxiliary electrode 8 is a stripe shape as shown in FIG. A lattice shape as shown in FIG.

  As described above, since the outer auxiliary electrode itself basically does not transmit light, light enters the photoelectric conversion layer from the opening of the outer auxiliary electrode. Therefore, it is preferable that the opening of the outer auxiliary electrode is relatively large. Specifically, the ratio of the openings of the outer auxiliary electrode is preferably about 50% to 95%, more preferably 70% to 95%. This is because if the ratio of the openings is less than the above range, light cannot be sufficiently transmitted. Further, when the ratio of the openings exceeds the above range, it is necessary to increase the thickness of the outer auxiliary electrode in order to give a desired resistance value to the outer auxiliary electrode, and the production efficiency is lowered.

  The pitch of the opening of the outer auxiliary electrode and the line width of the outer auxiliary electrode are preferably set so that the outer auxiliary electrode is disposed in a region where the inner auxiliary electrode is provided, such as the area of the entire outer auxiliary electrode, etc. It is appropriately selected depending on.

  The thickness of the outer auxiliary electrode is not particularly limited, but is preferably in the range of 0.5 μm to 10 μm, and more preferably in the range of 1 μm to 7 μm, particularly in the range of 3 μm to 5 μm. preferable. This is because if the thickness of the outer auxiliary electrode is too thin, the effect of reducing the resistance of the entire anode may not be sufficiently obtained. Moreover, it is because formation may become difficult when the thickness of an outer side auxiliary electrode is too thick.

The sheet resistance of the outer auxiliary electrode may be lower than the sheet resistance of the transparent electrode, but is preferably lower than the sheet resistance of the inner auxiliary electrode. Specifically, the sheet resistance of the outer auxiliary electrode is preferably 1Ω / □ or less, more preferably 0.5Ω / □ or less, and particularly preferably 0.1Ω / □ or less. This is because if the sheet resistance of the outer auxiliary electrode is larger than the above range, desired power generation efficiency may not be obtained.
The sheet resistance is measured based on JIS R1637 (low-efficiency test method for fine ceramic thin film: 4-probe method) using a surface resistance meter (Loresta MCP: 4-terminal probe) manufactured by Mitsubishi Chemical Corporation. It is the value.

  In addition, since the formation method of an outer side auxiliary electrode is described in detail in the section of “12. Manufacturing method of organic thin film solar cell” described later, description thereof is omitted here.

4). Inner auxiliary electrode The inner auxiliary electrode used in the present embodiment is formed in a pattern on one surface of the transparent substrate.

A metal is usually used as a material for forming the inner auxiliary electrode.
The metal used for the inner auxiliary electrode is the same as the metal used for the outer auxiliary electrode, and the description thereof is omitted here.

  The inner auxiliary electrode may be a single layer made of the above-described conductive metal, or a laminate of a conductive metal layer and a contact layer to ensure adhesion strength with the transparent substrate or the transparent electrode. May be. Examples of the material for forming the contact layer include nickel (Ni), chromium (Cr), titanium (Ti), and tantalum (Ta). The contact layer is laminated on the conductive metal layer in order to ensure adhesion strength, and may be laminated on either side of the conductive metal layer, or on both sides of the conductive metal layer. May be.

  The pattern shape of the inner auxiliary electrode is not particularly limited as long as it is a pattern having an opening, and is appropriately selected depending on desired conductivity, permeability, strength, and the like. For example, a mesh shape such as a polygonal shape or a circular lattice shape, a stripe shape, a comb tooth shape, and the like can be given. Among these, a mesh shape is preferable. This is because the resistance value of the inner auxiliary electrode can be further reduced.

  Since the inner auxiliary electrode itself basically does not transmit light, light enters the photoelectric conversion layer from the opening of the inner auxiliary electrode. For this reason, the opening of the inner auxiliary electrode is preferably relatively large. Specifically, the ratio of the openings of the inner auxiliary electrode is preferably about 50% to 95%, more preferably 70% to 95%. This is because if the ratio of the openings is less than the above range, light cannot be sufficiently transmitted. In addition, if the ratio of the openings exceeds the above range, the area of the inner auxiliary electrode becomes small, and the charge transfer efficiency at the inner auxiliary electrode may be reduced.

  The pitch of the opening of the inner auxiliary electrode and the line width of the inner auxiliary electrode are preferably set so that the outer auxiliary electrode is arranged in a region where the inner auxiliary electrode is provided, and the area of the entire inner auxiliary electrode, etc. It is appropriately selected depending on.

  The thickness of the inner auxiliary electrode is not particularly limited as long as it does not cause a short circuit between the transparent electrode and the counter electrode, and is appropriately determined depending on the thickness of the photoelectric conversion layer, the hole extraction layer, the electron extraction layer, and the like. Selected. Specifically, when the total thickness of layers formed between the transparent electrode and the counter electrode, such as a photoelectric conversion layer, a hole extraction layer, and an electron extraction layer, is 1, the thickness of the inner auxiliary electrode is 1 or less. Preferably, it is 0.5 or less, more preferably 0.3 or less. It is because there exists a possibility that a short circuit may arise between electrodes when the thickness of an inner side auxiliary electrode is thicker than the said range. More specifically, the thickness of the inner auxiliary electrode is preferably 500 nm or less, more preferably 300 nm or less, and particularly preferably 100 nm or less. It is because there exists a possibility that a short circuit may arise between electrodes when the thickness of an inner side auxiliary electrode is thicker than the said range. On the other hand, the lower limit of the thickness of the inner auxiliary electrode is preferably 30 nm. This is because when the film thickness is less than 30 nm, the metal thin film is not a continuous film, and the resistance value may become very large.

  The method for forming the inner auxiliary electrode is not particularly limited, and examples thereof include a method of forming a metal thin film on the entire surface and then patterning it into a mesh shape, a method of directly forming a mesh-like conductor, and the like. These methods are appropriately selected according to the material and thickness of the inner auxiliary electrode.

The method for forming the metal thin film is preferably a vacuum film forming method such as a vacuum deposition method, a sputtering method, or an ion plating method. That is, the inner auxiliary electrode is preferably a metal thin film formed by a vacuum film forming method. This is because the metal species formed by the vacuum film formation method has less inclusions than the plating film and can reduce the specific resistance, and the specific resistance can also be reduced compared to those formed using Ag paste or the like. A vacuum film-forming method is also suitable as a method for forming a metal thin film having a thickness of 1000 nm or less with good control and uniform thickness.
The method for patterning the metal thin film is not particularly limited as long as it can be accurately formed into a desired pattern, and examples thereof include a photoetching method.

5. Transparent electrode The transparent electrode used in this embodiment is formed on the inner auxiliary electrode. In the present invention, since the outer auxiliary electrode side serves as a light receiving surface, the transparent electrode is usually an electrode for extracting holes generated in the photoelectric conversion layer (hole extracting electrode).

  The constituent material of the transparent electrode is not particularly limited as long as it has conductivity and transparency. In—Zn—O (IZO), In—Sn—O (ITO), ZnO—Al, Zn—Sn— O etc. can be mentioned. Among them, it is preferable to select appropriately considering the work function of the constituent material of the counter electrode described later. For example, when the material constituting the counter electrode is a material having a low work function, the material constituting the transparent electrode is preferably a material having a high work function. ITO is preferably used as a material having conductivity and transparency and a high work function.

The total light transmittance of the transparent electrode is preferably 85% or more, more preferably 90% or more, and particularly preferably 92% or more. This is because when the total light transmittance of the transparent electrode is within the above range, light can be sufficiently transmitted through the transparent electrode and light can be efficiently absorbed by the photoelectric conversion layer.
The total light transmittance is a value measured using an SM color computer (model number: SM-C) manufactured by Suga Test Instruments Co., Ltd. in the visible light region.

The sheet resistance of the transparent electrode is preferably 20Ω / □ or less, more preferably 10Ω / □ or less, and particularly preferably 5Ω / □ or less. This is because if the sheet resistance is larger than the above range, the generated charge may not be sufficiently transmitted to the external circuit.
The sheet resistance is measured based on JIS R1637 (low-efficiency test method for fine ceramic thin film: 4-probe method) using a surface resistance meter (Loresta MCP: 4-terminal probe) manufactured by Mitsubishi Chemical Corporation. It is the value.

The transparent electrode may be a single layer or may be laminated using materials having different work functions.
As the film thickness of this transparent electrode, the film thickness is preferably in the range of 0.1 nm to 500 nm in the case of a single layer, and the total film thickness is preferably in the range of 0.1 nm to 500 nm. It is preferable to be within the range. If the film thickness is less than the above range, the sheet resistance of the transparent electrode becomes too large, and the generated charge may not be sufficiently transmitted to the external circuit. On the other hand, if the film thickness is thicker than the above range, the total light transmittance This is because there is a possibility that the photoelectric conversion efficiency is lowered.

  The transparent electrode may be formed on the entire surface of the substrate, or may be formed in a pattern.

  As a method for forming the transparent electrode, a general electrode forming method can be used.

6). Photoelectric Conversion Layer The photoelectric conversion layer used in this embodiment is formed between the transparent electrode and the counter electrode. The “photoelectric conversion layer” refers to a member that contributes to charge separation of the organic thin film solar cell and has a function of transporting generated electrons and holes toward electrodes in opposite directions.

  The photoelectric conversion layer may be a single layer having both an electron-accepting function and an electron-donating function (first aspect), or an electron-accepting layer having an electron-accepting function and an electron-donating function. A layer in which an electron donating layer having n is laminated may be used (second embodiment). Hereinafter, the description will be made separately for each aspect.

(1) 1st aspect The 1st aspect of the photoelectric converting layer in this embodiment is a single layer which has both an electron-accepting property and an electron-donating function, and contains an electron-donating material and an electron-accepting material. Is. In this photoelectric conversion layer, since charge separation occurs using a pn junction formed in the photoelectric conversion layer, it functions as a photoelectric conversion layer alone.

The electron donating material is not particularly limited as long as it has a function as an electron donor, but it is preferable that the material can be formed by a wet coating method. A polymer material is preferred.
The conductive polymer is a so-called π-conjugated polymer, which is composed of a π-conjugated system in which double bonds or triple bonds containing carbon-carbon or hetero atoms are alternately linked to single bonds, and exhibits semiconducting properties. It is. In the conductive polymer material, π conjugation is developed in the polymer main chain, so that charge transport in the main chain direction is basically advantageous. In addition, since the electron transfer mechanism of the conductive polymer is mainly hopping conduction between molecules by π stacking, it is advantageous not only for the main chain direction of the polymer but also for the charge transport in the film thickness direction of the photoelectric conversion layer. is there. Furthermore, since the conductive polymer material can be easily formed by a wet coating method using a coating solution in which the conductive polymer material is dissolved or dispersed in a solvent, a large-area organic thin film solar cell Can be manufactured at low cost without requiring expensive equipment.

  Examples of the electron-donating conductive polymer material include polyphenylene, polyphenylene vinylene, polysilane, polythiophene, polycarbazole, polyvinyl carbazole, porphyrin, polyacetylene, polypyrrole, polyaniline, polyfluorene, polyvinyl pyrene, polyvinyl anthracene, and derivatives thereof. And copolymers thereof, or phthalocyanine-containing polymers, carbazole-containing polymers, organometallic polymers, and the like.

Among the above, thiophene-fluorene copolymer, polyalkylthiophene, phenylene ethynylene-phenylene vinylene copolymer, phenylene ethynylene-thiophene copolymer, phenylene ethynylene-fluorene copolymer, fluorene-phenylene vinylene copolymer A thiophene-phenylene vinylene copolymer is preferably used. This is because the energy level difference is appropriate for many electron-accepting materials.
For example, a phenylene ethynylene-phenylene vinylene copolymer (Poly [1,4-phenyleneethynylene-1,4- (2,5-dioctadodecyloxyphenylene) -1,4-phenyleneethene-1,2-diyl-1,4- ( 2,5-dioctadodecyloxyphenylene) ethene-1,2-diyl]) is described in detail in Macromolecules, 35, 3825 (2002) and Micromol. Chem. Phys., 202, 2712 (2001).

  Further, the electron-accepting material is not particularly limited as long as it has a function as an electron acceptor, but it is preferable that the material can be formed by a wet coating method. A conductive polymer material is preferable. This is because the conductive polymer material has the advantages as described above.

Examples of the electron-accepting conductive polymer material include polyphenylene vinylene, polyfluorene, and derivatives thereof, and copolymers thereof, or carbon nanotubes, fullerene derivatives, CN group or CF ₃ group-containing polymers, and the like. -CF ₃ substituted polymer, and the like. Specific examples of the polyphenylene vinylene derivative include CN-PPV (Poly [2-Methoxy-5- (2′-ethylhexyloxy) -1,4- (1-cyanovinylene) phenylene]), MEH-CN-PPV (Poly [2 -Methoxy-5- (2′-ethylhexyloxy) -1,4- (1-cyanovinylene) phenylene]) and the like.

  Further, an electron accepting material doped with an electron donating compound, an electron donating material doped with an electron accepting compound, or the like can also be used. Among these, a conductive polymer material doped with an electron donating compound or an electron accepting compound is preferably used. Conductive polymer materials are basically advantageous in charge transport in the direction of the main chain because of the development of π conjugation in the polymer main chain, and are doped with electron-donating compounds and electron-accepting compounds. This is because electric charges are generated in the π-conjugated main chain, and the electrical conductivity can be greatly increased.

Examples of the electron-accepting conductive polymer material doped with the electron-donating compound include the above-described electron-accepting conductive polymer material. As the electron-donating compound to be doped, for example, a Lewis base such as an alkali metal such as Li, K, Ca, or Cs or an alkaline earth metal can be used. The Lewis base acts as an electron donor.
Examples of the electron-donating conductive polymer material doped with the electron-accepting compound include the above-described electron-donating conductive polymer material. As the electron-accepting compound to be doped, for example, a Lewis acid such as FeCl ₃ (III), AlCl ₃ , AlBr ₃ , AsF ₆ or a halogen compound can be used. In addition, Lewis acid acts as an electron acceptor.

  As the film thickness of the photoelectric conversion layer, the film thickness generally employed in bulk heterojunction organic thin film solar cells can be employed. Specifically, it can be set within a range of 0.2 nm to 3000 nm, and preferably within a range of 1 nm to 600 nm. This is because when the film thickness is thicker than the above range, the volume resistance in the photoelectric conversion layer may increase. On the other hand, if the film thickness is thinner than the above range, light may not be sufficiently absorbed.

  The mixing ratio of the electron-donating material and the electron-accepting material is appropriately adjusted to an optimal mixing ratio depending on the type of material used.

  The method for forming the photoelectric conversion layer is not particularly limited as long as it can be uniformly formed in a predetermined film thickness, but a wet coating method is preferably used. This is because if the wet coating method is used, the photoelectric conversion layer can be formed in the air, and the cost can be reduced and the area can be easily increased.

  The method for applying the photoelectric conversion layer coating solution is not particularly limited as long as it can uniformly apply the photoelectric conversion layer coating solution. For example, a die coating method, a spin coating method, a dip coating method, and the like. Examples thereof include a coating method, a roll coating method, a bead coating method, a spray coating method, a bar coating method, a gravure coating method, an ink jet method, a screen printing method, and an offset printing method.

After application of the coating liquid for photoelectric conversion layer, a drying treatment for drying the formed coating film may be performed. It is because productivity can be improved by removing the solvent etc. which are contained in the coating liquid for photoelectric conversion layers at an early stage.
As a method for the drying treatment, for example, a general method such as heat drying, air drying, or vacuum drying can be used.

(2) Second Aspect In the second aspect of the photoelectric conversion layer in this embodiment, an electron accepting layer having an electron accepting function and an electron donating layer having an electron donating function are laminated. . Hereinafter, the electron-accepting layer and the electron-donating layer will be described.

(Electron-accepting layer)
The electron-accepting layer used in this embodiment has an electron-accepting function and contains an electron-accepting material.

  The electron-accepting material is not particularly limited as long as it has a function as an electron acceptor, but is preferably a material that can be formed into a film by a wet coating method. A polymer material is preferred. This is because the conductive polymer material has the advantages as described above. Specific examples include the same electron-accepting conductive polymer materials used for the photoelectric conversion layer of the first aspect.

  As the film thickness of the electron-accepting layer, a film thickness generally employed in a bilayer type organic thin film solar cell can be employed. Specifically, it can be set within a range of 0.1 nm to 1500 nm, and preferably within a range of 1 nm to 300 nm. This is because if the film thickness is larger than the above range, the volume resistance in the electron-accepting layer may be increased. On the other hand, if the film thickness is thinner than the above range, light may not be sufficiently absorbed.

  The method for forming the electron-accepting layer can be the same as the method for forming the photoelectric conversion layer of the first aspect.

(Electron donating layer)
The electron donating layer used in this embodiment has an electron donating function and contains an electron donating material.

  The electron donating material is not particularly limited as long as it has a function as an electron donor, but it is preferable that the material can be formed by a wet coating method. A polymer material is preferred. This is because the conductive polymer material has the advantages as described above. Specific examples include the same electron donating conductive polymer materials used for the photoelectric conversion layer of the first aspect.

  As a film thickness of the electron donating layer, a film thickness generally employed in a bilayer type organic thin film solar cell can be employed. Specifically, it can be set within a range of 0.1 nm to 1500 nm, and preferably within a range of 1 nm to 300 nm. This is because if the film thickness is larger than the above range, the volume resistance in the electron donating layer may be increased. On the other hand, if the film thickness is thinner than the above range, light may not be sufficiently absorbed.

  The method for forming the electron donating layer can be the same as the method for forming the photoelectric conversion layer of the first aspect.

7. Counter electrode The counter electrode used in this embodiment is an electrode facing the transparent electrode. Usually, the counter electrode is an electrode for extracting electrons generated in the photoelectric conversion layer (electron extraction electrode). In this embodiment, since the outer auxiliary electrode side is the light receiving surface, the counter electrode does not have to be transparent.

  The material for forming the counter electrode is not particularly limited as long as it has conductivity. However, since the counter electrode is an electron extraction electrode, it preferably has a low work function. Specific examples of the material having a low work function include Li, In, Al, Ca, Mg, Sm, Tb, Yb, Zr, and LiF.

The counter electrode may be a single layer or may be stacked using materials having different work functions.
When the counter electrode is a single layer, the thickness of the counter electrode is within a range of 0.1 nm to 500 nm, particularly 1 nm to 300 nm. It is preferable to be within. If the film thickness is smaller than the above range, the sheet resistance of the counter electrode may be too large, and the generated charge may not be sufficiently transmitted to the external circuit. This is because the transmittance is lowered and the photoelectric conversion efficiency may be lowered.

  The counter electrode may be formed on the entire surface of the photoelectric conversion layer, or may be formed in a pattern.

  As a method for forming the counter electrode, a general electrode forming method can be used. For example, a vacuum evaporation method or a pattern evaporation method using a metal mask can be used.

8). Transparent substrate The transparent substrate used in the present embodiment is not particularly limited. For example, a transparent rigid material having no flexibility such as quartz glass, Pyrex (registered trademark), or a synthetic quartz plate, or a transparent resin film. And a transparent flexible material having flexibility, such as an optical resin plate.

  Among the above, the transparent substrate is preferably a flexible material such as a transparent resin film. Transparent resin films are excellent in processability, and are useful in the realization of organic thin-film solar cells that reduce manufacturing costs, reduce weight, and are difficult to break, and expand the applicability to various applications such as application to curved surfaces. is there.

9. Hole Extraction Layer In this embodiment, it is preferable that the hole extraction layer 5 is formed between the photoelectric conversion layer 6 and the transparent electrode 4 (hole extraction electrode) as illustrated in FIG. The hole extraction layer is a layer provided so that holes can be easily extracted from the photoelectric conversion layer to the hole extraction electrode. Thereby, since the hole extraction efficiency from the photoelectric conversion layer to the hole extraction electrode is increased, the photoelectric conversion efficiency can be improved.

The material used for the hole extraction layer is not particularly limited as long as it is a material that stabilizes the extraction of holes from the photoelectric conversion layer to the hole extraction electrode. Specifically, conductive organic compounds such as doped polyaniline, polyphenylene vinylene, polythiophene, polypyrrole, polyparaphenylene, polyacetylene, triphenyldiamine (TPD), or electron donation such as tetrathiofulvalene, tetramethylphenylenediamine, etc. An organic material that forms a charge transfer complex composed of an organic compound and an electron-accepting compound such as tetracyanoquinodimethane and tetracyanoethylene. Also, a thin film of metal such as Au, In, Ag, Pd, etc. can be used. Furthermore, a thin film of metal or the like may be formed alone or in combination with the above organic material.
Among these, polyethylenedioxythiophene (PEDOT) and triphenyldiamine (TPD) are particularly preferably used.

  The film thickness of the hole extraction layer is preferably in the range of 10 nm to 200 nm when the organic material is used, and in the range of 0.1 nm to 5 nm in the case of the metal thin film. Is preferred.

10. Electron Extraction Layer In this embodiment, an electron extraction layer may be formed between the photoelectric conversion layer and the counter electrode (electron extraction electrode). The electron extraction layer is a layer provided so that electrons can be easily extracted from the photoelectric conversion layer to the electron extraction electrode. Thereby, since the electron extraction efficiency from the photoelectric conversion layer to the electron extraction electrode is increased, the photoelectric conversion efficiency can be improved.

  The material used for the electron extraction layer is not particularly limited as long as it is a material that stabilizes the extraction of electrons from the photoelectric conversion layer to the electron extraction electrode. Specifically, doped polyaniline, polyphenylene vinylene, polythiophene, polypyrrole, polyparaphenylene, polyacetylene, conductive organic compounds such as triphenyldiamine (TPD), or electron donation such as tetrathiofulvalene, tetramethylphenylenediamine, etc. An organic material that forms a charge transfer complex composed of an organic compound and an electron-accepting compound such as tetracyanoquinodimethane and tetracyanoethylene. Moreover, the metal dope layer with an alkali metal or alkaline-earth metal is mentioned. Suitable materials include bathocuproin (BCP) or bathophenantrone (Bphen) and metal doped layers such as Li, Cs, Ba, Sr.

11. Other Configurations The organic thin film solar cell of this embodiment exhibits good power generation efficiency even in a large area. The area of the organic thin film solar cell is not particularly limited, but is preferably 50 mm □ or more.

The organic thin-film solar cell of this embodiment may have the structural member mentioned later as needed other than the structural member mentioned above. For example, the organic thin film solar cell of this embodiment has functions such as a protective sheet, a filler layer, a barrier layer, a protective hard coat layer, a strength support layer, an antifouling layer, a high light reflection layer, a light containment layer, and a sealing material layer. It may have a layer. In addition, an adhesive layer may be formed between the functional layers depending on the layer configuration.
These functional layers can be the same as those described in JP-A-2007-73717.

12 2. Manufacturing method of organic thin-film solar cell The manufacturing method of the organic thin-film solar cell of this embodiment has two preferable aspects by the formation process of a connection electroconductive part. Hereinafter, the description will be made separately for each aspect.

(1) 1st aspect of the manufacturing method of an organic thin film solar cell The 1st aspect of the manufacturing method of the organic thin film solar cell of this embodiment forms a through-hole in a transparent substrate, and fills the said through-hole with electrically conductive paste. A connection conductive part forming step of forming a connection conductive part penetrating the transparent substrate, and forming a metal thin film for the inner auxiliary electrode on one surface of the transparent substrate on which the connection conductive part is formed, and the connection conductive part is A metal foil film for the outer auxiliary electrode is formed on the other surface of the formed transparent substrate, a resist is disposed on the metal thin film for the outer auxiliary electrode and the metal thin film for the inner auxiliary electrode, and the outer auxiliary electrode is formed by a photoetching method. The metal thin film for the inner auxiliary electrode and the metal thin film for the inner auxiliary electrode are patterned to form a conductive pattern for the inner auxiliary electrode so as to be in contact with the connection conductive portion on one surface of the transparent substrate, and the conductive connection is formed on the other surface of the transparent substrate. A pattern forming step of forming a conductive pattern for the outer auxiliary electrode so as to be in contact with the portion, and a plating step of placing a protective layer on the conductive pattern for the inner auxiliary electrode and plating on the conductive pattern for the outer auxiliary electrode An auxiliary electrode forming step of forming an inner auxiliary electrode on one surface of the transparent substrate and forming an outer auxiliary electrode on the other surface of the transparent substrate; and on the inner auxiliary electrode after the auxiliary electrode forming step. And a transparent electrode forming step of forming a transparent electrode.

9 and 10 are process diagrams showing an example of a method for producing the organic thin-film solar battery of this embodiment.
First, the through-hole 21 is formed in the transparent substrate 2 with a laser (FIGS. 9A and 9B). Next, the through hole 21 is filled with the conductive paste 9a by screen printing to form the connection conductive portion 9 that penetrates the transparent substrate (FIG. 9C).
Next, the inner auxiliary electrode metal thin film 3a is formed on one surface of the transparent substrate 2 provided with the connection conductive portion 9, and the outer auxiliary electrode metal thin film 8a is formed on the other surface of the transparent substrate 2 (FIG. 9 (d)). Next, resists 22a and 23a are respectively disposed on the outer auxiliary electrode metal thin film 8a and the inner auxiliary electrode metal thin film 3a (FIG. 9E), and exposure and development are performed to form resist images 22b and 23b. (FIG. 9 (f)). Subsequently, the outer auxiliary electrode metal thin film 8a and the inner auxiliary electrode metal thin film 3a exposed using the resist images 22b and 23b as a mask are etched (FIG. 9G), and the resist images 22b and 23b are removed. The mesh-shaped inner auxiliary electrode conductive pattern 3b is formed on one surface of the transparent substrate 2 so as to contact the connection conductive portion 9, and the mesh-shaped auxiliary pattern 9b is formed on the other surface of the transparent substrate 2 so as to contact the connection conductive portion 9. An outer auxiliary electrode conductive pattern 8b is formed (FIG. 10A). Thereby, the inner auxiliary electrode 3 composed of the inner auxiliary electrode conductive pattern 3b is obtained.
Next, a protective layer 25 is disposed on the inner auxiliary electrode 3 formed on the other surface of the transparent substrate 2 (FIG. 10B), and the outer auxiliary electrode conductive material formed on one surface of the transparent substrate 2 is disposed. Electrolytic plating is performed on the pattern 8b to form a plating layer 8c, and the outer auxiliary electrode 8 composed of the outer auxiliary electrode conductive pattern 8b and the plating layer 8c is obtained (FIG. 10C). Subsequently, the protective layer 25 is removed (FIG. 10D).
Next, the transparent electrode 4 is formed on the inner auxiliary electrode 3 (FIG. 10E).

  Thereafter, although not shown, a hole extraction layer and a photoelectric conversion layer are formed on the transparent electrode, a counter electrode is formed on the photoelectric conversion layer, and an optical member is formed on the outer auxiliary electrode. If necessary, an electron extraction layer may be formed on the photoelectric conversion layer, and a counter electrode may be formed on the electron extraction layer.

In the example shown in FIGS. 9D to 9G, the outer auxiliary electrode metal thin film and the inner auxiliary electrode metal thin film are patterned in the same shape, but the present invention is not limited to this. The metal thin film for the inner auxiliary electrode and the metal thin film for the inner auxiliary electrode may be patterned into different shapes.
Hereinafter, each process in the manufacturing method of the organic thin-film solar cell of this aspect is demonstrated.

(I) Connection conductive part formation process The connection conductive part formation process in this aspect forms a through-hole in a transparent substrate, fills the through-hole with a conductive paste, and forms a connection conductive part that penetrates the transparent substrate. It is a process.

As a method for forming the through hole in the transparent substrate, a general method for forming a through hole can be applied, and the method is appropriately selected according to the type of the transparent substrate. In the case where the transparent substrate is a transparent flexible material such as a transparent resin film, a method of forming a through hole includes a method using a laser. On the other hand, when the transparent substrate is a transparent rigid material such as quartz glass, a method of forming a through hole includes a method using a drill, a sand blast method, and the like.
As the laser, a short wavelength laser such as an excimer laser or a YAG laser can be used.

  The diameter of the through hole is appropriately set according to the desired diameter of the connection conductive portion.

  The conductive paste is obtained by dispersing metal fine particles in a resin. As the metal fine particles, the metal used for the connection conductive portion can be used.

  As a method of filling the through holes with the conductive paste, any method that can fill all the through holes with the conductive paste may be used, and examples thereof include a screen printing method.

  In the connection conductive part forming step, instead of filling the through hole with a conductive paste to form the connection conductive part, a method of filling the through hole by plating (via filling) or a method of covering the wall surface of the through hole by plating It is also possible to apply a method (through-hole plating) for forming a connection conductive portion.

(Ii) Auxiliary electrode forming step In the auxiliary electrode forming step in this embodiment, the inner auxiliary electrode metal thin film is formed on one surface of the transparent substrate on which the connection conductive portion is formed, and the connection conductive portion is formed on the transparent substrate. An outer auxiliary electrode metal foil film is formed on the other surface of the substrate, a resist is disposed on the outer auxiliary electrode metal thin film and the inner auxiliary electrode metal thin film, and the outer auxiliary electrode metal thin film and The inner auxiliary electrode metal thin film is patterned to form an inner auxiliary electrode conductive pattern on one surface of the transparent substrate so as to be in contact with the connection conductive portion, and to be in contact with the connection conductive portion on the other surface of the transparent substrate. Forming the outer auxiliary electrode conductive pattern on the inner auxiliary electrode conductive pattern, placing a protective layer on the inner auxiliary electrode conductive pattern, and plating on the outer auxiliary electrode conductive pattern. Has a to plating step, the transparent inner auxiliary electrode formed on one surface of the substrate, a step of forming the outer auxiliary electrode on the other surface of the transparent substrate.
Hereinafter, each process in the auxiliary electrode forming process will be described.

(Pattern formation process)
In the pattern forming step in this aspect, the inner auxiliary electrode metal thin film is formed on one surface of the transparent substrate on which the connection conductive portion is formed, and the outer auxiliary electrode is formed on the other surface of the transparent substrate on which the connection conductive portion is formed. An electrode metal foil film is formed, a resist is disposed on the outer auxiliary electrode metal thin film and the inner auxiliary electrode metal thin film, and the outer auxiliary electrode metal thin film and the inner auxiliary electrode metal thin film are patterned by a photoetching method. Then, an inner auxiliary electrode conductive pattern is formed on one surface of the transparent substrate so as to be in contact with the connection conductive portion, and an outer auxiliary electrode conductive pattern is formed on the other surface of the transparent substrate so as to be in contact with the connection conductive portion. It is a process of forming.

  Examples of the method for forming the metal thin film for the outer auxiliary electrode and the metal thin film for the inner auxiliary electrode include a vacuum deposition method, a sputtering method, and an ion plating method.

As the resist, a general resist used for forming electrodes can be used.
As a method of disposing a resist on the outer auxiliary electrode metal thin film and the inner auxiliary electrode metal thin film, for example, a resist material may be applied on the outer auxiliary electrode metal thin film and the inner auxiliary electrode metal thin film. A dry resist film may be laminated on the outer auxiliary electrode metal thin film and the inner auxiliary electrode metal thin film.
As a resist exposure method and development method, general methods can be applied.

  After the exposure and development of the resist, the exposed outer auxiliary electrode metal thin film and inner auxiliary electrode metal thin film are removed by etching.

  After the etching of the outer auxiliary electrode metal thin film and the inner auxiliary electrode metal thin film, the resist is removed. A general method can be applied as a method for removing the resist.

(Plating process)
The plating step in this aspect is a step of disposing a protective layer on the inner auxiliary electrode and plating on the outer auxiliary electrode conductive pattern.

  The resist can be used as a protective layer disposed on the other surface of the transparent substrate.

  The plating method is not particularly limited as long as it can be applied to the conductive pattern for the outer auxiliary electrode, and electrolytic plating is usually used.

  The conditions for electrolytic plating are not particularly limited as long as a plating layer having a desired thickness can be formed, and can be general conditions.

  Although it does not specifically limit as thickness of plating, It is preferable to exist in the range of 0.5 micrometer-20 micrometers, Especially, it exists in the range of 0.5 micrometer-5 micrometers, especially the range of 0.7 micrometer-2 micrometers. It is preferable. This is because if the thickness of the plating is too thin, the effect of reducing the resistance of the entire electrode may not be sufficiently obtained. Moreover, it is because formation may become difficult when the thickness of plating is too thick.

(Iii) Transparent electrode formation process The transparent electrode formation process in this aspect is a process of forming a transparent electrode on the inner auxiliary electrode after the auxiliary electrode formation process.
In addition, since it described in the item of the said transparent electrode about the formation method of a transparent electrode, description here is abbreviate | omitted.

(2) 2nd aspect of the manufacturing method of an organic thin film solar cell The 2nd aspect of the manufacturing method of the organic thin film solar cell of this embodiment forms a conductive bump on metal foil, The said conductive bump of the said metal foil A connecting conductive part forming step of forming a connecting conductive part penetrating through the transparent substrate by laminating a transparent substrate on the surface on which the transparent bump is formed, and a metal foil of the transparent substrate A metal thin film for the inner auxiliary electrode is formed on the surface opposite to the surface on which the metal foil is provided, a resist is disposed on the metal foil and the metal thin film for the inner auxiliary electrode, and the metal foil and the inner auxiliary electrode are formed by a photoetching method. By patterning the electrode metal thin film, an inner auxiliary electrode is formed on one surface of the transparent substrate so as to be in contact with the connection conductive portion, and an outer auxiliary electrode is formed on the other surface of the transparent substrate so as to be in contact with the connection conductive portion. Shape electrode An auxiliary electrode forming step to be formed, and a transparent electrode forming step of forming a transparent electrode on the inner auxiliary electrode.

11 and 12 are process diagrams showing an example of a method for producing the organic thin-film solar cell of this embodiment.
First, the conductive bump 9b is formed on the metal foil 8d by screen printing using a conductive paste (FIG. 11A). Next, the transparent substrate 2 is laminated on the surface of the metal foil 8d on which the conductive bumps 9b are formed and pressed, and the conductive bumps 9b penetrate the transparent substrate 2 so that the tops of the conductive bumps 9b are exposed ( FIG. 11B). Subsequently, the top portion of the conductive bump 9b is polished, the surface of the transparent substrate 2 is flattened, and the connection conductive portion 9 is formed (FIG. 11C).
Next, the inner auxiliary electrode metal thin film 3a is formed on the surface of the transparent substrate 2 opposite to the surface on which the metal foil 8d is formed (FIG. 11D). Next, resists 22a and 23a are respectively disposed on the metal foil 8d and the inner auxiliary electrode metal thin film 3a (FIG. 11E), and pattern exposure and development are performed to form resist images 22b and 23b (FIG. 12). (A)). Subsequently, the exposed metal foil 8d and the inner auxiliary electrode metal thin film 3a are etched using the resist images 22b and 23b as a mask (FIG. 12B), the resist images 22b and 23b are removed, and the transparent substrate 2 is removed. A mesh-like inner auxiliary electrode 3 is formed on one surface of the transparent substrate 2 so as to be in contact with the connection conductive portion 9, and a mesh-shaped outer auxiliary electrode 8 is formed on the other surface of the transparent substrate 2 so as to be in contact with the connection conductive portion 9. (FIG. 12 (c)).
Next, the transparent electrode 4 is formed on the inner auxiliary electrode 3 (FIG. 12D).

Thereafter, although not shown, a hole extraction layer and a photoelectric conversion layer are formed on the transparent electrode, a counter electrode is formed on the photoelectric conversion layer, and an optical member is formed on the outer auxiliary electrode. If necessary, an electron extraction layer may be formed on the photoelectric conversion layer, and a counter electrode may be formed on the electron extraction layer.
Hereinafter, each process in the manufacturing method of the organic thin-film solar cell of this aspect is demonstrated.

(I) Connection conductive part formation process The connection conductive part formation process in this aspect forms a conductive bump on the metal foil, laminates a transparent substrate on the surface of the metal foil on which the conductive bump is formed, In this step, the conductive bump is penetrated through the transparent substrate to form a connection conductive portion penetrating the transparent substrate.

  As a metal which comprises metal foil, what is necessary is just to be able to form a conductive bump, and the metal used for the said outside auxiliary electrode can be mentioned.

Examples of the method for forming the conductive bump include a screen printing method using a conductive paste.
As the conductive paste, the one described in the first embodiment can be used.

  When passing the conductive bumps through the transparent substrate, the transparent substrate is laminated on the surface of the metal foil on which the conductive bumps are formed, and heated and pressed to expose the top of the conductive bumps. preferable. Furthermore, after passing the conductive bumps through the transparent substrate, it is preferable to polish the exposed top portions of the conductive bumps to flatten the surface of the transparent substrate.

  The transparent substrate is not particularly limited as long as the conductive bumps can be penetrated, and a transparent flexible material having flexibility such as a transparent resin film and an optical resin plate is preferably used.

(Ii) Auxiliary electrode forming step In the auxiliary electrode forming step in this embodiment, an inner auxiliary electrode metal thin film is formed on the surface of the transparent substrate opposite to the surface on which the metal foil is provided. A resist is disposed on the auxiliary electrode metal thin film, the metal foil and the inner auxiliary electrode metal thin film are patterned by a photoetching method, and the inner auxiliary electrode is in contact with the connection conductive portion on one surface of the transparent substrate. And forming an outer auxiliary electrode on the other surface of the transparent substrate so as to be in contact with the connection conductive portion.

  The resist, the resist arrangement method, the resist exposure method, the resist development method, the metal foil etching method, the resist removal method, and the like are the same as those described in the first embodiment.

(Iii) Transparent electrode formation process The transparent electrode formation process in this aspect is a process of forming a transparent electrode on the said inner side auxiliary electrode.
In addition, since it described in the item of the said transparent electrode about the formation method of a transparent electrode, description here is abbreviate | omitted.

II. Second Embodiment A second embodiment of the organic thin-film solar cell of the present invention includes a transparent substrate, a transparent electrode formed on one surface of the transparent substrate, a photoelectric conversion layer formed on the transparent electrode, The counter electrode formed on the photoelectric conversion layer, the outer auxiliary electrode formed in a pattern on the other surface of the transparent substrate, having a lower resistance value than the transparent electrode, the transparent substrate, and the outer auxiliary electrode A connecting conductive portion that electrically connects the electrode and the transparent electrode; and an optical member that is formed on the outer auxiliary electrode and guides light incident on the light shielding region provided with the outer auxiliary electrode to the photoelectric conversion layer; It is characterized by having.

The organic thin film solar cell of this embodiment will be described with reference to the drawings.
FIG. 13 is a schematic cross-sectional view showing an example of the organic thin film solar cell of this embodiment. In the example shown in FIG. 13, the organic thin-film solar cell 1 includes a transparent substrate 2, a transparent electrode 4 formed on one surface of the transparent substrate 2, a hole extraction layer 5 formed on the transparent electrode 4, The photoelectric conversion layer 6 formed on the hole extraction layer 5, the counter electrode 7 formed on the photoelectric conversion layer 6, and formed on the other surface of the transparent substrate 2 in a mesh shape, more resistant than the transparent electrode 4. The outer auxiliary electrode 8 having a low value, the connection conductive portion 9 that penetrates the transparent substrate 2 and electrically connects the outer auxiliary electrode 8 and the transparent electrode 4, and the outer auxiliary electrode 8 are formed on the outer auxiliary electrode 8. A convex lens 11 a that guides light incident on the light shielding region 10 provided to the photoelectric conversion layer 6 is provided.

The transparent electrode is formed on one surface of the transparent substrate and the outer auxiliary electrode is formed on the other surface of the transparent substrate. The surface opposite to the surface of the transparent substrate on which the transparent electrode is formed It means that an outer auxiliary electrode is formed on the surface.
The light shielding region is a region where the outer auxiliary electrode is provided.

  In the organic thin film solar cell 1 illustrated in FIG. 13, first, the incident light L is incident on the convex lens 11 a and is condensed by the light converging action of the convex lens 11, and the transparent substrate 2, the transparent electrode 4 and the hole extraction layer 5. And enters the photoelectric conversion layer 6. At this time, since the light L incident on the convex lens 11a in the light shielding region 10 is collected by the light converging action of the convex lens, it can be efficiently incident on the photoelectric conversion layer 6 without being blocked by the outer auxiliary electrode 8. it can. Then, charges (holes and electrons) are generated in the photoelectric conversion layer 6 by the incident light L. Next, the generated charges (holes) move in the film thickness direction of the photoelectric conversion layer 6 and are extracted to the hole extraction layer 5, and the transparent electrode 4 is contacted at the contact interface between the hole extraction layer 5 and the transparent electrode 4. It is taken out. On the other hand, the generated charges (electrons) move in the film thickness direction of the photoelectric conversion layer 6 and are taken out to the counter electrode 7 at the contact interface between the photoelectric conversion layer 6 and the counter electrode 7.

  As described above, according to this embodiment, since the optical member that guides the light incident on the light shielding region such as the convex lens to the photoelectric conversion layer is formed, the amount of incident light is greatly reduced even if the outer auxiliary electrode is formed. Efficient power generation is possible without causing it to occur.

  Further, according to this embodiment, the outer auxiliary electrode and the transparent electrode are electrically connected by the connection conductive portion, and the anode side electrode is composed of the outer auxiliary electrode and the transparent electrode. Even when the resistance is relatively high, the resistance of the whole anode can be reduced. That is, the generated power can be efficiently collected by the outer auxiliary electrode. Therefore, even if the organic thin-film solar cell is increased in area, it is possible to maintain high power generation efficiency.

  Furthermore, according to this embodiment, since the outer auxiliary electrode is formed on the light receiving surface side of the transparent substrate, the thickness of the outer auxiliary electrode does not affect the short circuit between the electrodes. Therefore, the outer auxiliary electrode can be made relatively thick. Therefore, even when the opening area of the outer auxiliary electrode is increased, it is possible to easily obtain a desired resistance value by increasing the thickness of the outer auxiliary electrode. The resistance of the whole anode can be controlled by adjusting the thickness of the outer auxiliary electrode.

  The transparent substrate, the transparent electrode, the photoelectric conversion layer, the counter electrode, the optical member, the hole extraction layer, the electron extraction layer, and the like are the same as those in the first embodiment, and a description thereof is omitted here. Hereinafter, the other structure in the organic thin-film solar cell of this embodiment is demonstrated.

1. Connection conductive part The connection conductive part used in this embodiment penetrates the transparent substrate and electrically connects the outer auxiliary electrode and the transparent electrode.

  Note that the forming material, shape, forming position, diameter, forming method, and the like of the connection conductive portion are the same as those described in the first embodiment, and thus the description thereof is omitted here.

  Since the connection conductive part only needs to electrically connect the outer auxiliary electrode and the transparent electrode, the density of the connection conductive part is usually smaller than the density of the outer auxiliary electrode. The density of the connection conductive portion is appropriately selected according to a desired resistance value, the diameter of the connection conductive portion, and the like.

2. Outer Auxiliary Electrode The outer auxiliary electrode used in the present embodiment is formed in a pattern on the other surface of the transparent substrate, and has a lower resistance value than the transparent electrode.

  The forming material, configuration, pattern shape, opening ratio, thickness, sheet resistance, forming method, and the like of the outer auxiliary electrode are the same as those described in the first embodiment, and therefore are described here. Is omitted.

  The pitch of the openings of the outer auxiliary electrode and the line width of the outer auxiliary electrode are appropriately selected according to the area of the entire outer auxiliary electrode and the like.

3. 2. Manufacturing method of organic thin-film solar cell The manufacturing method of the organic thin-film solar cell of this embodiment has two preferable aspects by the formation process of a connection electroconductive part.

  First, in the first aspect, a connection conductive part forming step for forming a connection conductive part penetrating the transparent substrate by forming a through hole in the transparent substrate and filling the through hole with a conductive paste, and the connection An outer auxiliary electrode metal thin film is formed on one surface of the transparent substrate on which the conductive portion is formed, a resist is disposed on the outer auxiliary electrode metal thin film, and the outer auxiliary electrode metal thin film is patterned by a photoetching method. And forming a conductive pattern on one surface of the transparent substrate so as to be in contact with the connection conductive portion, and disposing a protective layer on the other surface of the transparent substrate, An auxiliary electrode forming step of forming an outer auxiliary electrode on one surface of the transparent substrate; and a transparent surface on the other surface of the transparent substrate after the auxiliary electrode forming step. Those having a transparent electrode forming step of forming an electrode.

14 and 15 are process diagrams showing an example of a method for manufacturing the organic thin-film solar cell of the above embodiment.
First, the through-hole 21 is formed in the transparent substrate 2 with a laser (FIGS. 14A and 14B). Next, the through hole 21 is filled with the conductive paste 9a by screen printing to form the connection conductive portion 9 that penetrates the transparent substrate (FIG. 14C).
Next, the outer auxiliary electrode metal thin film 8a is formed on one surface of the transparent substrate 2 provided with the connection conductive portion 9 (FIG. 14D). Next, a resist 22a is disposed on the outer auxiliary electrode metal thin film 8a, a protective layer 24 is disposed on the other surface of the transparent substrate 2 (FIG. 14E), and pattern exposure and development are performed on the resist 22a. Then, a resist image 22b is formed (FIG. 14F). Subsequently, the outer auxiliary electrode metal thin film 8a exposed using the resist image 22b as a mask is etched (FIG. 14G), the resist image 22b and the protective layer 24 are removed, and one surface of the transparent substrate 2 is removed. A mesh-shaped outer auxiliary electrode conductive pattern 8b is formed so as to be in contact with the connection conductive portion 9 (FIG. 15A).
Next, the protective layer 25 is disposed again on the other surface of the transparent substrate 2 (FIG. 15B), and electroplating is performed on the outer auxiliary electrode conductive pattern 8b to form a plating layer 8c. The outer auxiliary electrode 8 composed of the conductive pattern 8b and the plating layer 8c is obtained (FIG. 15C). Subsequently, the protective layer 25 is removed (FIG. 15D).
Next, the transparent electrode 4 is formed on the other surface of the transparent substrate 2 (FIG. 15E).

  Thereafter, although not shown, a hole extraction layer and a photoelectric conversion layer are formed on the transparent electrode, a counter electrode is formed on the photoelectric conversion layer, and an optical member is formed on the outer auxiliary electrode. If necessary, an electron extraction layer may be formed on the photoelectric conversion layer, and a counter electrode may be formed on the electron extraction layer.

  In addition, about each process in the 1st aspect, since it can be made to be the same as that of the 1st aspect of the manufacturing method of the organic thin film solar cell of the said 1st embodiment, description here is abbreviate | omitted.

  Next, in the second aspect, a conductive bump is formed on the metal foil, a transparent substrate is laminated on the surface of the metal foil on which the conductive bump is formed, and the conductive bump is attached to the transparent substrate. A connecting conductive part forming step of forming a connecting conductive part penetrating through the transparent substrate, placing a resist on the metal foil, patterning the metal foil by a photoetching method, and forming one of the transparent substrates An auxiliary electrode forming step of forming an outer auxiliary electrode so as to be in contact with the connection conductive portion on the surface, and a transparent electrode forming step of forming a transparent electrode on the other surface of the transparent substrate.

16 and 17 are process diagrams showing an example of a method for producing the organic thin-film solar battery of the above aspect.
First, the conductive bumps 9b are formed on the metal foil 8d by screen printing using a conductive paste (FIG. 16A). Next, the transparent substrate 2 is laminated on the surface of the metal foil 8d on which the conductive bumps 9b are formed and pressed, and the conductive bumps 9b penetrate the transparent substrate 2 so that the tops of the conductive bumps 9b are exposed ( FIG. 16 (b)). Subsequently, the top portion of the conductive bump 9b is polished, the surface of the transparent substrate 2 is flattened, and the connection conductive portion 9 is formed (FIG. 16C).
Next, a resist 22a is disposed on the metal foil 8d, a protective layer 24 is disposed on the other surface of the transparent substrate 2 (FIG. 16D), and the resist 22a is exposed and developed to form a resist image 22b. Is formed (FIG. 16E). Subsequently, the exposed metal foil 8d is etched using the resist image 22b as a mask (FIG. 17A), the resist image 22b and the protective layer 24 are removed, and the connection conductive portion is formed on one surface of the transparent substrate 2. A mesh-like outer auxiliary electrode 8 is formed so as to be in contact with 9 (FIG. 17B).
Next, the transparent electrode 4 is formed on the other surface of the transparent substrate 2 (FIG. 17C).

Thereafter, although not shown, a hole extraction layer and a photoelectric conversion layer are formed on the transparent electrode, a counter electrode is formed on the photoelectric conversion layer, and an optical member is formed on the outer auxiliary electrode. If necessary, an electron extraction layer may be formed on the photoelectric conversion layer, and a counter electrode may be formed on the electron extraction layer.
In the above aspect, the transparent electrode forming step may be performed after the auxiliary electrode forming step, or the transparent electrode forming step may be performed after the connecting conductive portion forming step and before the auxiliary electrode forming step.

  In addition, about each process in the 2nd aspect, since it can be made to be the same as that of each process in the 2nd aspect of the manufacturing method of the organic thin-film solar cell of the said 1st embodiment, description here is abbreviate | omitted.

III. Third Embodiment A third embodiment of the organic thin film solar cell of the present invention includes a transparent substrate, a transparent electrode and a patterned inner auxiliary electrode laminated in random order on one surface of the transparent substrate, the transparent electrode, A photoelectric conversion layer formed on the inner auxiliary electrode, a counter electrode formed on the photoelectric conversion layer, and a light shielding region formed on the other surface of the transparent substrate and provided with the inner auxiliary electrode. An optical member that guides incident light to the photoelectric conversion layer, and the inner auxiliary electrode has a thickness that does not cause a short circuit between the transparent electrode, the inner auxiliary electrode, and the counter electrode. It is what.

The organic thin film solar cell of this embodiment will be described with reference to the drawings.
FIG. 18 is a schematic cross-sectional view showing an example of the organic thin film solar cell of this embodiment. In the example shown in FIG. 18, the organic thin film solar cell 1 includes a transparent substrate 2, an inner auxiliary electrode 3 formed in a mesh shape on one surface of the transparent substrate 2, and a transparent electrode formed on the inner auxiliary electrode 3. 4, a hole extraction layer 5 formed on the transparent electrode 4, a photoelectric conversion layer 6 formed on the hole extraction layer 5, a counter electrode 7 formed on the photoelectric conversion layer 6, and a transparent substrate 2 and a convex lens 11 a that guides light incident on the light shielding region 10 provided with the inner auxiliary electrode 3 to the photoelectric conversion layer 6. The inner auxiliary electrode 3 has a thickness such that no short circuit occurs between the inner auxiliary electrode 3 and the transparent electrode 4 and the counter electrode 8.

The transparent electrode and the inner auxiliary electrode are formed on one surface of the transparent substrate, and the optical member is formed on the other surface of the transparent substrate. The transparent electrode and the inner auxiliary electrode of the transparent substrate are formed. It means that an optical member is formed on the surface opposite to the surface.
The light shielding region is a region where the inner auxiliary electrode is provided.

  In the organic thin-film solar cell 1 illustrated in FIG. 18, first, the incident light L is incident on the convex lens 11 a and is condensed by the light converging action of the convex lens, and the transparent substrate 2, the transparent electrode 4, and the hole extraction layer 5. And enters the photoelectric conversion layer 6. At this time, since the light L incident on the convex lens 11a in the light shielding region 10 is collected by the converging action of the light of the convex lens, it can be efficiently incident on the photoelectric conversion layer 6 without being blocked by the inner auxiliary electrode 3. it can. Then, charges (holes and electrons) are generated in the photoelectric conversion layer 6 by the incident light L. Next, the generated charges (holes) move in the film thickness direction of the photoelectric conversion layer 6 and are extracted to the hole extraction layer 5, and the transparent electrode 4 is contacted at the contact interface between the hole extraction layer 5 and the transparent electrode 4. It is taken out. On the other hand, the generated charges (electrons) move in the film thickness direction of the photoelectric conversion layer 6 and are taken out to the counter electrode 7 at the contact interface between the photoelectric conversion layer 6 and the counter electrode 7.

  As described above, according to this embodiment, since the optical member that guides the light incident on the light shielding region such as the convex lens to the photoelectric conversion layer is formed, the amount of incident light is greatly reduced even if the inner auxiliary electrode is formed. Efficient power generation is possible without causing it to occur.

  Further, according to this embodiment, since the anode side electrode is a laminate of the inner auxiliary electrode and the transparent electrode, even if the sheet resistance of the transparent electrode is relatively high, the sheet of the inner auxiliary electrode By making the resistance sufficiently low, the sheet resistance of the whole anode can be reduced. Therefore, even if the organic thin-film solar cell is increased in area, the generated power can be collected efficiently, and high power generation efficiency can be maintained.

  Furthermore, according to this embodiment, since the thickness of the inner auxiliary electrode is such that no short circuit occurs between the inner auxiliary electrode and the transparent electrode and the counter electrode, the organic thin film solar cell has the inner auxiliary electrode. However, it is possible to prevent a short circuit from occurring between the electrodes.

  The transparent substrate, the transparent electrode, the photoelectric conversion layer, the counter electrode, the optical member, the hole extraction layer, the electron extraction layer, and the like are the same as those in the first embodiment, and a description thereof is omitted here. Hereinafter, the other structure in the organic thin-film solar cell of this embodiment is demonstrated.

(Inner auxiliary electrode)
The inner auxiliary electrode used in this embodiment is a patterned electrode, and the inner auxiliary electrode has a thickness that does not cause a short circuit between the inner auxiliary electrode and the transparent electrode and the counter electrode.

  The thickness of the inner auxiliary electrode is not particularly limited as long as it does not cause a short circuit between the inner auxiliary electrode and the transparent electrode and the counter electrode. Photoelectric conversion layer, hole extraction layer, electron extraction layer, etc. It is appropriately selected according to the thickness. Specifically, assuming that the total thickness of the layers formed between the inner auxiliary electrode and the transparent electrode and the counter electrode, such as the photoelectric conversion layer, the hole extraction layer, and the electron extraction layer, is 1, The thickness is preferably 5 or less, more preferably 3 or less, and still more preferably 1.5 or less. It is because there exists a possibility that a short circuit may arise between electrodes when the thickness of an inner side auxiliary electrode is thicker than the said range. More specifically, the thickness of the inner auxiliary electrode is preferably in the range of 10 nm to 1000 nm, in the range of 100 nm to 1000 nm, in particular in the range of 200 nm to 800 nm, in particular in the range of 300 nm to 500 nm. Is preferred. This is because if the thickness of the inner auxiliary electrode is thinner than the above range, the sheet resistance of the inner auxiliary electrode may become too large. Moreover, it is because there exists a possibility that a short circuit may arise between electrodes when the thickness of an inner side auxiliary electrode is thicker than the said range.

A metal is usually used as a material for forming the inner auxiliary electrode. Examples of the metal used for the inner auxiliary electrode include aluminum (Al), gold (Au), silver (Ag), cobalt (Co), nickel (Ni), platinum (Pt), copper (Cu), aluminum alloy, and the like. The conductive metal can be mentioned. Among the conductive metals described above, those having a relatively low electrical resistance value are preferred. Examples of such a conductive metal include Al, Au, Ag, and Cu.
In addition, the inner auxiliary electrode may be a single layer made of the conductive metal as described above, and a conductive metal layer and a contact layer are appropriately laminated in order to improve adhesion to the transparent substrate or the transparent electrode. It may be what you did. Examples of the material for forming the contact layer include nickel (Ni), chromium (Cr), titanium (Ti), and tantalum (Ta). The contact layer is laminated on the conductive metal layer in order to obtain adhesion between the desired inner auxiliary electrode and the transparent substrate or transparent electrode, and may be laminated only on one side of the conductive metal layer. You may laminate | stack on both sides of a metal layer.

  A preferable metal may be selected according to the work function of the material for forming the counter electrode. For example, when considering the work function of the material for forming the counter electrode, the inner auxiliary electrode is a hole extraction electrode, and therefore the metal preferably has a high work function. Specifically, Al is preferably used.

  The pattern shape of the inner auxiliary electrode is not particularly limited as long as it is a pattern having an opening, and is appropriately selected depending on desired conductivity, permeability, strength, and the like. For example, a mesh shape such as a polygonal shape or a circular lattice shape, a stripe shape, a comb tooth shape, and the like can be given. Among these, a mesh shape is preferable. This is because the resistance value of the inner auxiliary electrode can be further reduced.

  Since the inner auxiliary electrode itself basically does not transmit light, light enters the photoelectric conversion layer from the opening of the inner auxiliary electrode. For this reason, the opening of the inner auxiliary electrode is preferably relatively large. Specifically, the ratio of the openings of the inner auxiliary electrode is preferably about 50% to 95%, more preferably 70% to 95%. This is because if the ratio of the openings is less than the above range, light cannot be sufficiently transmitted. In addition, if the ratio of the openings exceeds the above range, the area of the inner auxiliary electrode becomes small, and the charge transfer efficiency at the inner auxiliary electrode may be reduced.

  The pitch of the openings of the inner auxiliary electrode and the line width of the inner auxiliary electrode are appropriately selected according to the area of the entire inner auxiliary electrode and the like.

The sheet resistance of the inner auxiliary electrode is preferably 5Ω / □ or less, more preferably 3Ω / □ or less, and particularly preferably 1Ω / □ or less. This is because if the sheet resistance of the inner auxiliary electrode is larger than the above range, desired power generation efficiency may not be obtained.
The sheet resistance is measured based on JIS R1637 (low-efficiency test method for fine ceramic thin film: 4-probe method) using a surface resistance meter (Loresta MCP: 4-terminal probe) manufactured by Mitsubishi Chemical Corporation. It is the value.

  As for the formation position of the inner auxiliary electrode, the inner auxiliary electrode 3 and the transparent electrode 4 may be laminated in this order on the transparent substrate 2 as illustrated in FIG. 18, and on the transparent substrate 2 as illustrated in FIG. The transparent electrode 4 and the inner auxiliary electrode 3 may be laminated in this order. Especially, it is preferable to laminate | stack in order of an inner side auxiliary electrode and a transparent electrode on the transparent substrate. This is because the larger the contact area between the transparent electrode, the photoelectric conversion layer, the hole extraction layer, and the like, the better the interface bondability and the higher the hole transfer efficiency.

  The method for forming the inner auxiliary electrode is not particularly limited, and examples thereof include a method of patterning after forming a metal thin film on the entire surface, and a method of directly forming a patterned conductor. These methods are appropriately selected according to the forming material and configuration of the inner auxiliary electrode.

The method for forming the metal thin film is preferably a vacuum film forming method such as a vacuum deposition method, a sputtering method, or an ion plating method. That is, the inner auxiliary electrode is preferably a metal thin film formed by a vacuum film forming method. The metal species formed by the vacuum film formation method has less inclusions than the plating film and can reduce the specific resistance. In addition, the specific resistance of the metal thin film formed by the vacuum film formation method can be reduced as compared with that formed using an Ag paste or the like. A vacuum film forming method is also suitable as a method for forming a metal thin film having a thickness of 1 μm or less to a uniform thickness by precisely controlling the film thickness.
The method for patterning the metal thin film is not particularly limited as long as it can be accurately formed into a desired pattern, and examples thereof include a photoetching method.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

Hereinafter, the present invention will be specifically described with reference to examples.
[Example 1]
Using a PEN substrate having an outer size of 60 mm □, a through hole having a diameter of 100 μm was formed at a desired position by laser irradiation. The through-hole was filled with Ag paste by screen printing to form a connection conductive portion. Thereafter, Ni / Cu / Ni is formed on both sides of the substrate at a thickness of 20 nm / 300 nm / 20 nm by sputtering (film forming pressure: 0.1 Pa, film forming power: 180 W, time: 3 minutes / 12 minutes / 3 minutes). Lamination was performed, and etching was performed so that the pattern was at the same position on the front and back of the substrate, and a mesh-shaped auxiliary electrode was formed. Further, at that time, the through hole was shaped such that the upper and lower surfaces of the connection conductive portion were in contact with the mesh-like auxiliary electrode formed on both sides of the substrate.

  Next, a transparent UV curable resin was applied to the entire surface of one mesh auxiliary electrode of the PEN substrate with a desired film thickness. A mold prepared so that a convex lens shape can be formed is arranged so that a convex lens is formed at a desired position of the opening of the mesh auxiliary electrode, pressed against the UV curable resin, and further UV-irradiated by UV irradiation. And a convex lens shape was formed on the light receiving surface side of the PEN substrate.

  Subsequently, a reactive ion plating method using a pressure gradient plasma gun (power: 3.7 kW, oxygen partial pressure: 73%, film-forming pressure: 0 is formed on the upper surface of the other mesh auxiliary electrode of the PEN substrate. An ITO film (film thickness: 150 nm, sheet resistance: 20Ω / □), which is a transparent electrode, was formed at a rate of 3 Pa, a film forming rate: 150 nm / min, and a substrate temperature: 20 ° C. Next, the substrate on which the ITO film was formed was cleaned using acetone, a substrate cleaning solution, and IPA. As a result, the apparent sheet resistance of the ITO electrode (sheet resistance as a laminate of the ITO electrode and the mesh auxiliary electrode) was reduced to 0.1Ω / □.

Next, a conductive polymer paste (poly- (3,4-ethylenedioxythiophene) dispersion) is formed on the substrate on which the ITO film is formed by spin coating, and then at 150 ° C. for 30 minutes. It was made to dry and the hole extraction layer (film thickness: 100 nm) was formed.
Next, polythiophene (P3HT: poly (3-hexylthiophene-2,5-diyl)) and C60PCBM ([6,6] -phenyl-C61-butyric acid mettric ester) are dissolved in bromobenzene to obtain a solid content concentration of 1. A 4 wt% photoelectric conversion layer coating solution was prepared. Next, the photoelectric conversion layer coating solution was applied on the hole extraction layer by a spin coating method at a rotation speed of 600 rpm to form a photoelectric conversion layer. Thereafter, the substrate on which the photoelectric conversion layer was formed was exposed to the atmosphere.

Next, Ca / Al (thickness: 60 nm / 200 nm) was formed on the photoelectric conversion layer by a vacuum deposition method to obtain a metal electrode.
Next, the substrate on which the photoelectric conversion layer and the like were formed on a hot plate at a temperature of 150 ° C. was dried by heating. Finally, it was sealed from above the metal electrode with a sealing glass material and an adhesive sealing material to obtain an organic thin film solar cell.

[Comparative Example 1]
An organic thin film solar cell was produced in the same manner as in Example 1 except that the convex lens shape was not formed.

[Comparative Example 2]
An organic thin film solar cell was produced in the same manner as in Example 1 except that the convex lens shape was not formed and the mesh auxiliary electrode was not formed on both sides of the PEN substrate.

[Evaluation]
The organic thin film solar cell of 50 mm □ size of Example 1 and Comparative Example 1 (apparent sheet resistance of ITO electrode: 0.1Ω / □) and the organic thin film solar cell of 50 mm □ size of Comparative Example 2 (sheet resistance of ITO electrode) : 20Ω / □) was evaluated for power generation. As an evaluation method, A. M1.5 and simulated sunlight (100 mW / cm ² ) were used as an irradiation light source, and current-voltage characteristics were evaluated by applying voltage with a source measure unit (HP 4100, manufactured by HP).
While the power generation efficiency of the organic thin film solar cell of Comparative Example 2 was 0.05%, the power generation efficiency of the organic thin film solar cell of Comparative Example 1 was improved to 1.5%. Furthermore, in the organic thin film solar cell of Example 1, the power generation efficiency was improved to 1.8%. By placing the mesh-like auxiliary electrode on the ITO electrode, the light transmission is reduced, but the power loss due to the reduction in the apparent resistance value of the ITO electrode is reduced, and as a result, the conversion efficiency is improved. It was done. Furthermore, it is confirmed that the power generation efficiency is further improved by arranging a convex lens on the light-receiving surface side and efficiently irradiating incident light not on the mesh-shaped auxiliary electrode serving as a light shielding area but on the opening of the mesh-shaped auxiliary electrode. It was done. In Example 1, since the mesh-shaped auxiliary electrode which becomes a light shielding area | region is formed in both surfaces of a transparent substrate, a convex lens is arrange | positioned on the light-receiving surface of a transparent substrate, and it injects into the light-shielding area | region in which the mesh-shaped auxiliary electrode was provided. The incident light quantity could be secured by condensing the light at the opening of the mesh auxiliary electrode.

[Example 2]
Using a PEN substrate having an outer size of 50 mm □, a through hole having a diameter of 100 μm was formed at a desired position by laser irradiation. The through-hole was filled with Ag paste by screen printing to form a connection conductive portion. After that, Ni / Cu / Ni is deposited to a thickness of 20 nm / 300 nm / only on the light receiving surface side of the substrate by sputtering (film forming pressure: 0.1 Pa, film forming power: 180 W, time: 3 minutes / 12 minutes / 3 minutes). Lamination was performed at 20 nm, and etching was performed to obtain a desired shape, thereby forming a mesh-like auxiliary electrode. Further, a reactive ion plating method using a pressure gradient plasma gun (power: 3.7 kW, oxygen partial pressure: 73%, film forming pressure: on the surface opposite to the mesh auxiliary electrode forming surface of the substrate. An ITO film (film thickness: 150 nm, sheet resistance: 20Ω / □), which is a transparent electrode, was formed at a rate of 0.3 Pa, a film formation rate: 150 nm / min, and a substrate temperature: 20 ° C. A substrate in which the mesh-shaped auxiliary electrode and the ITO electrode were connected via the connection conductive portion was obtained.

  Next, a transparent UV curable resin was applied to the entire surface of the mesh auxiliary electrode with a desired film thickness. A mold made so that a concave lens shape can be formed is arranged so that a concave lens is formed at a desired position of the opening of the mesh auxiliary electrode, pressed against the UV curable resin, and further UV-irradiated by UV irradiation. And a concave lens shape was formed on the light receiving surface side of the PEN substrate.

  Then, it carried out similarly to Example 1, and produced the organic thin film solar cell.

[Comparative Example 3]
An organic thin film solar cell was produced in the same manner as in Example 2 except that the concave lens shape was not formed.

[Comparative Example 4]
An organic thin film solar cell was produced in the same manner as in Example 2 except that the concave lens shape was not formed and the mesh auxiliary electrode was not formed on the light receiving surface side of the PEN substrate.

[Evaluation]
50 mm □ organic thin film solar cells of Example 2 and Comparative Example 3 (apparent sheet resistance of ITO electrode: 0.1Ω / □) and 50 mm □ organic thin film solar cells of Comparative Example 4 (sheet resistance of ITO electrode) : 20Ω / □) was evaluated for power generation. As an evaluation method, A. M1.5 and simulated sunlight (100 mW / cm ² ) were used as an irradiation light source, and current-voltage characteristics were evaluated by applying voltage with a source measure unit (HP 4100, manufactured by HP).
While the power generation efficiency of the organic thin film solar cell of Comparative Example 4 was 0.05%, the power generation efficiency of the organic thin film solar cell of Comparative Example 3 was improved to 1.2%. Furthermore, in the organic thin film solar cell of Example 2, the power generation efficiency was improved to 1.6%. By placing the mesh-like auxiliary electrode on the ITO electrode, the light transmission is reduced, but the power loss due to the reduction in the apparent resistance value of the ITO electrode is reduced, and as a result, the conversion efficiency is improved. It was done. Furthermore, it was confirmed that the power generation efficiency is further improved by disposing a concave lens on the light receiving surface side and introducing incident light below the mesh auxiliary electrode serving as a light shielding region. In Example 2, since the mesh-like auxiliary electrode serving as a light-shielding region is formed on the light-receiving surface side of the transparent substrate, a concave lens is disposed on the light-receiving surface of the transparent substrate, and the light-shielding region where the mesh-like auxiliary electrode is provided. By introducing incident light to the lower side of the mesh-shaped auxiliary electrode, it was possible to secure the amount of incident light.

[Example 3]
Using a PEN base material with an outer size of 50 mm □, the sputtering method (film forming pressure: 0.1 Pa, film forming power: 180 W, time: 3 minutes / 12 minutes / 3 minutes) on the opposite side of the light receiving surface of the PEN base material Then, Ni / Cu / Ni was formed into a film with a thickness of 20 nm / 300 nm / 20 nm, and was etched so as to have a desired mesh shape, thereby forming a mesh-shaped auxiliary electrode. On the upper surface of the mesh auxiliary electrode, a reactive ion plating method using a pressure gradient plasma gun (power: 3.7 kW, oxygen partial pressure: 73%, film forming pressure: 0.3 Pa, film forming rate: 150 nm / An ITO film (film thickness: 150 nm, sheet resistance: 20 Ω / □), which is a transparent electrode, was formed by min, substrate temperature: 20 ° C.). A transparent substrate on which a mesh auxiliary electrode and ITO electrode were formed was obtained.
Thereafter, a transparent UV curable resin was applied to the entire surface of the PEN substrate opposite to the mesh auxiliary electrode forming surface with a desired film thickness. A mold prepared so that a convex lens can be formed is arranged so that a convex lens is formed at a predetermined position of the opening of the mesh auxiliary electrode, pressed against the UV curable resin, and further UV-irradiated with UV curable resin. The convex lens shape was formed in the light-receiving surface side of the PEN substrate.

  Then, it carried out similarly to Example 1, and produced the organic thin film solar cell.

[Comparative Example 5]
An organic thin-film solar cell was produced in the same manner as in Example 3 except that the convex lens shape was not formed.

[Comparative Example 6]
An organic thin film solar cell was produced in the same manner as in Example 3 except that the convex lens shape was not formed and the mesh auxiliary electrode was not formed on the opposite side of the light receiving surface of the PEN substrate.

[Evaluation]
50 mm □ organic thin film solar cells of Example 3 and Comparative Example 5 (apparent sheet resistance of ITO electrode: 0.1Ω / □) and 50 mm □ organic thin film solar cells of Comparative Example 6 (ITO electrode sheet resistance) : 20Ω / □) was evaluated for power generation. As an evaluation method, A. M1.5 and simulated sunlight (100 mW / cm ² ) were used as an irradiation light source, and current-voltage characteristics were evaluated by applying voltage with a source measure unit (HP 4100, manufactured by HP).
While the power generation efficiency of the organic thin film solar cell of Comparative Example 6 was 0.05%, the power generation efficiency of the organic thin film solar cell of Comparative Example 5 was improved to 1.6%. Furthermore, in the organic thin film solar cell of Example 3, the power generation efficiency was improved to 1.9%. By placing the mesh-like auxiliary electrode on the ITO electrode, the light transmission is reduced, but the power loss due to the reduction in the apparent resistance value of the ITO electrode is reduced, and as a result, the conversion efficiency is improved. It was done. Furthermore, it is confirmed that the power generation efficiency is further improved by arranging a convex lens on the light-receiving surface side and efficiently irradiating incident light not on the mesh-shaped auxiliary electrode serving as a light shielding area but on the opening of the mesh-shaped auxiliary electrode. It was done. In Example 3, since the mesh-like auxiliary electrode serving as a light-shielding region is formed on the opposite side of the light-receiving surface of the transparent substrate, a light-shielding light provided with a mesh-like auxiliary electrode by arranging a convex lens on the light-receiving surface of the transparent substrate. The amount of incident light was able to be secured by condensing the light incident on the region at the opening of the mesh auxiliary electrode.

DESCRIPTION OF SYMBOLS 1 ... Organic thin film solar cell 2 ... Board | substrate 3 ... Inner auxiliary electrode 4 ... Transparent electrode 5 ... Hole extraction layer 6 ... Photoelectric conversion layer 7 ... Opposite electrode 8 ... Outer auxiliary electrode 9 ... Connection electroconductive part 10 ... Light-shielding area | region 11a ... Convex lens (Optical member)
11b: Concave lens (optical member)
11c Prism (optical member)
L ... Incident light

Claims (6)

A transparent substrate;
An inner auxiliary electrode formed in a pattern on one surface of the transparent substrate;
A transparent electrode formed on the inner auxiliary electrode;
A photoelectric conversion layer formed on the transparent electrode;
A counter electrode formed on the photoelectric conversion layer;
An outer auxiliary electrode formed in a pattern on the other surface of the transparent substrate and having a lower resistance than the transparent electrode;
A connection conductive portion that penetrates the transparent substrate and electrically connects the outer auxiliary electrode and the inner auxiliary electrode;
An optical member that is formed on the outer auxiliary electrode and guides light incident on a light shielding region provided with the outer auxiliary electrode and the inner auxiliary electrode to the photoelectric conversion layer ;
The organic thin-film solar cell , wherein the optical member guides light to the photoelectric conversion layer in the light shielding region . A transparent substrate;
A transparent electrode formed on one surface of the transparent substrate;
A photoelectric conversion layer formed on the transparent electrode;
A counter electrode formed on the photoelectric conversion layer;
An outer auxiliary electrode formed in a pattern on the other surface of the transparent substrate and having a lower resistance than the transparent electrode;
A connection conductive portion that penetrates the transparent substrate and electrically connects the outer auxiliary electrode and the transparent electrode;
An optical member that is formed on the outer auxiliary electrode and guides light incident on a light shielding region provided with the outer auxiliary electrode to the photoelectric conversion layer ;
The organic thin-film solar cell , wherein the optical member guides light to the photoelectric conversion layer in the light shielding region . A transparent substrate;
A transparent electrode and a patterned inner auxiliary electrode laminated in random order on one surface of the transparent substrate;
A photoelectric conversion layer formed on the transparent electrode and the inner auxiliary electrode;
A counter electrode formed on the photoelectric conversion layer;
An optical member that is formed on the other surface of the transparent substrate and guides light incident on a light shielding region where the inner auxiliary electrode is provided to the photoelectric conversion layer;
The thickness of the inner auxiliary electrode is a thickness that does not cause a short circuit between the transparent electrode and the inner auxiliary electrode and the counter electrode,
The organic thin-film solar cell , wherein the optical member guides light to the photoelectric conversion layer in the light shielding region .   The optical member is a convex lens or a concave lens;
  The organic thin-film solar cell according to any one of claims 1 to 3, wherein an end of the convex lens or the concave lens is located in the light shielding region.   The optical member is a convex lens;
  The organic thin-film solar cell according to any one of claims 1 to 4, wherein a focal point of the convex lens is located in the transparent substrate.   The optical member is a prism;
  The organic thin-film solar cell according to any one of claims 1 to 5, wherein the prism is disposed only in the light shielding region.

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