WO2013038540A1 - Electrode for photoelectric conversion devices, and photoelectric conversion device using same - Google Patents

Abstract

An electrode for photoelectric conversion devices is configured of: an insulating substrate (11) that has a plurality of through holes (11a) arranged in a pattern; one electrode (12) that is formed by filling a through hole (11a) of the substrate (11) with a conductive material so as to be exposed on the surface of the substrate (11); and another electrode (13) that is formed on the surface of the substrate (11) so as to have a space from the one electrode (12). A photoelectric conversion device is configured using this electrode for photoelectric conversion devices together with an organic semiconductor (14) of a p-layer, which is provided on the electrode (12), an organic semiconductor (15) of an n-layer, which is provided on the electrode (13), and a protection layer (16), which is provided so as to cover the organic semiconductor (14) of a p-layer and the organic semiconductor (15) of an n-layer.

Description

Electrode for photoelectric conversion device and photoelectric conversion device using the same

The present invention relates to an electrode for a photoelectric conversion device used for a photoelectric conversion device and a photoelectric conversion device using the same.

A photoelectric conversion device is a device that converts light into electrical energy and a device that converts electrical energy into light. Examples of the former include solar cells, and examples of the latter include light emitting diodes.

Today, the need for solar power supply as a clean energy is recognized again. There are various types of solar cells such as Si solar cells, compound solar cells, and organic semiconductor thin film solar cells.

The Si solar cell will be described by taking a single crystal Si solar cell as an example. A pn junction is formed by using a surface layer of the wafer as an n-type semiconductor by vapor phase diffusion or implantation of n-type impurity ions into a p-type single crystal wafer. A solar cell having a sandwich structure is manufactured by forming a front electrode and a back electrode.

There are various types of compound solar cells, but they have the advantages of high energy conversion efficiency, low light degradation due to secular change, excellent radiation resistance, wide light absorption wavelength range, and large light absorption coefficient. A chalcopyrite solar cell will be described as an example. This is a solar cell provided with a CIGS layer made of a chalcopyrite compound (Cu (In + Ga) Se ₂ ) containing Group I, Group III and Group VI elements as a p-type light absorption layer (for example, Patent Documents) 1).

This solar cell with a CIGS layer generally prevents a back electrode layer, which is a positive electrode made of a Mo metal layer, on a glass substrate such as a soda lime glass (SLG) substrate, and Na unevenness caused by the SLG substrate. For forming a multilayer structure including a Na dip layer, a CIGS light absorption layer, an n-type buffer layer, and an outermost surface layer formed of a transparent electrode layer as a negative electrode. Here, the n-type buffer layer is made of CdS, ZnO, InS or the like, and the transparent electrode layer is made of ZnOAl or the like.

In this multilayer laminated structure, when irradiation light enters from the light receiving portion on the surface, a pair of electrons and holes are excited in the vicinity of the pn junction of the multilayer laminated structure by the irradiation light having energy greater than the band gap. Occurs. The excited electrons and holes reach the pn junction by diffusion, and the electrons are collected in the n region and the holes are separated in the p region due to the internal electric field of the junction. As a result, the n region is negatively charged, the p region is positively charged, and a potential difference is generated between the electrodes provided in each region. Using this potential difference as an electromotive force, a photocurrent is obtained when the electrodes are connected by a conductive wire.

The CIGS light absorbing layer is obtained by the following process. That is, the substrate itself provided with the In layer and the Cu—Ga layer as a precursor is accommodated in the annealing chamber and preheated. Thereafter, the precursor is converted into a CIGS layer by raising the temperature of the chamber to a temperature range of 500 to 520 ° C. while introducing H ₂ Se gas through a gas introducing tube inserted into the annealing chamber.

On the other hand, organic semiconductor thin film solar cells are attracting attention as solar cells suitable for mass production because they can be formed by a coating method. The organic solar cell has a so-called bulk heterojunction structure in which an organic donor material and an organic acceptor material are mixed. Among them, an organic thin-film solar cell capable of forming a cathode on a flexible substrate by coating and a low-temperature process has been developed (for example, Patent Document 2).

According to Patent Document 2, an organic semiconductor thin film solar cell has a structure in which an anode, a photoelectric conversion layer having a bulk heterojunction structure, and a cathode are sequentially laminated on one surface of a substrate, and is composed of silver oxide and a reducing agent. By adopting a structure in which a cathode and an electron transport layer doped with an organic metal are coated and laminated in the vicinity of the cathode, not only the cathode is formed at a low temperature, but also the bonding between the organic metal doped layer and the cathode is improved. .

Japanese Patent Laid-Open No. 2006-196771 JP 2011-124468 A

However, in the conventional structure, it is necessary to provide a pair of electrodes across a region that becomes a pn junction. For this reason, the light irradiation side electrode is required to have good light transmittance and low electrical resistance. For this reason, the light irradiation side electrode needs to be formed by vapor deposition or plating of an expensive rare metal. In addition, the process steps are complicated accordingly.

Therefore, an object of the present invention is to provide an electrode structure for a photoelectric conversion device that does not require light transmittance as an electrode material and a photoelectric conversion device using the same.

In order to achieve the above object, an electrode for a photoelectric conversion device according to the present invention is formed on an insulating base material having a plurality of through holes according to a pattern and a surface of the base material while filling the through holes of the base material with a conductive material. One electrode formed so as to be exposed, and the other electrode provided so as to have a gap between the one electrode on the surface of the substrate.

In the above configuration, one electrode is connected to each other by a conductive film formed on the back surface of the base material.

In the above configuration, one of the electrodes has a protrusion protruding from the surface of the substrate.

In the above configuration, one electrode and the other electrode are formed of either Cu or Al.

In order to achieve the above object, the photoelectric conversion device of the present invention is provided with a p-layer organic semiconductor made of a hole transport material on one of the electrodes for the optoelectronic device of the present invention, and the other An n-layer organic semiconductor made of an electron transport material is provided on the electrode, and a p-layer organic semiconductor and an n-layer organic semiconductor are alternately formed on the same surface.

In order to achieve the above object, the photoelectric conversion device of the present invention is provided with an n-layer organic semiconductor made of an electron transport material on one of the electrodes for the optoelectronic device of the present invention, and the other A p-layer organic semiconductor made of a hole transport material is provided on the electrode, and the p-layer organic semiconductor and the n-layer organic semiconductor are alternately formed on the same surface.

In the above configuration, the p-layer organic semiconductor and the n-layer organic semiconductor are covered with a transparent protective layer.

Conventionally, a p-layer organic semiconductor is laminated on one electrode and an n-layer organic semiconductor is laminated thereon to form a pn junction, and a transparent electrode is formed on the n-layer organic semiconductor as the other electrode. Although the photoelectric conversion device is configured by sequentially stacking, according to the present invention, one electrode functioning as a p-type electrode and the other electrode functioning as an n-type electrode are formed on the same surface. Therefore, the transparent electrode material conventionally required as the electrode material becomes unnecessary. This alternating array of planar electrode structures can be fabricated on a non-flexible or flexible substrate. Since an organic semiconductor can be provided on the electrode by coating, the manufacturing process is not complicated, and the electrode can be manufactured at a low cost.

It is sectional drawing of the photoelectric conversion device which concerns on embodiment of this invention. It is a top view of the electrode for photoelectric conversion devices shown in FIG. It is an enlarged view of the area | region of the code | symbol A shown in FIG. It is a top view which shows the modification of the electrode for photoelectric conversion devices.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In particular, the photoelectric conversion device will be described assuming that a solar cell converts light into electric energy. However, the present invention can also be applied to a device that converts electric energy into light energy.

FIG. 1 is a cross-sectional view of a photoelectric conversion device according to an embodiment of the present invention.
As shown in FIG. 1, the photoelectric conversion device 1 according to the embodiment of the present invention fills an insulating base material 11 having a plurality of through holes 11 a according to a pattern and the through holes 11 a of the base material 11 with a conductive material 17. However, one electrode 12 formed so as to be exposed on the surface of the base material 11 and the other electrode 13 provided so as to have, for example, a gap 18 so as not to contact the one electrode 12 on the surface of the base material 11 The p-layer organic semiconductor 14 provided on one electrode 12, the n-layer organic semiconductor 15 provided on the other electrode 13, and the p-layer organic semiconductor 14 and the n-layer organic semiconductor 15 are covered. And a protective layer 16 provided as described above.

The p-layer organic semiconductor 14 and the n-layer organic semiconductor 15 are arranged so as to be alternately arranged in the direction in which the upper surface of the substrate 11 spreads. Overlaid on top. In addition, in the same manner as the p-layer organic semiconductor 14 and the n-layer organic semiconductor 15, the one electrode 12 and the other electrode 13 constituting the electrode for the photoelectric conversion device also spread in the surface on the upper surface side of the substrate 11. It is formed so as to be arranged alternately. Therefore, the surface on which light is incident can be made the protective layer 16 without providing an electrode as in Patent Document 2, and as a result, a rare metal for a transparent electrode provided on the light irradiation side as in Patent Document 2. Need not be used as a material. Therefore, as will be described later, Cu, Al, or the like can be used for the electrode for the photoelectric conversion device. Further, in this embodiment, not only the one electrode 12 and the other electrode 13 are arranged on the same surface, but also the extraction of the wiring can be arranged on each of the opposing surfaces of the substrate, so that the structure of the extraction wiring is not complicated. .

Furthermore, the configuration of the photoelectric conversion device 1 will be specifically described.

The base material 11 can be applied to various materials such as a ceramic substrate such as a glass substrate, a resin substrate, and a printed circuit board. When a resin substrate or the like is used as the base material 11, the mounting surface of the photoelectric conversion device 1 may be a curved surface instead of a flat surface.

One electrode 12 will be described. As shown in FIG. 1, with respect to one electrode 12, the conductive material 17 is filled in the through hole 11 a of the base material 11 and one end thereof is exposed at least on the surface of the base material 11. Part 12a.

FIG. 2 is a plan view of the photoelectric conversion device electrode shown in FIG. 1, and FIG. 3 is an enlarged view of a portion A in FIG. As shown in FIG. 3, dot-shaped electrode main body portions 12 a are arranged on the surface of the base material 11 at intervals in the row direction, and they are also arranged at intervals in the column direction. In the embodiment shown in FIGS. 2 and 3, the electrode main body portions 12a are formed at intervals in each row, and the odd-numbered electrode main body portions 12a and the even-numbered electrode main body portions 12a are in the row direction. It is staggered and is provided alternately. That is, they are not aligned in the column direction. The electrode main body portions 12a may be aligned in the row direction and the column direction, and may be arranged in a matrix at intervals.

As shown in FIG. 1, each electrode main body 12 a preferably has its tip projecting from the surface of the substrate 11. An organic semiconductor dot is formed on the protruding portion by coating, but the connection between the organic conductor and the electrode body 12a is ensured because the electrode body 12a projects from the surface of the substrate 11. It is.

Each electrode 12 extends from the electrode body portion 12 a protruding from the surface of the base material 11 to the back surface of the base material 11 by a filling portion 12 b in which the through hole 11 a of the base material 11 is filled with the conductive material 17. The filling portions 12b are electrically connected by a wiring electrode portion 12c formed on the back surface of the base material 11. An end portion of the wiring electrode portion 12c becomes the external connection portion 12d. Here, by making the wiring electrode portion 12c have a predetermined planar shape, the filling portions 12b can be electrically connected according to the planar shape.

The other electrode 13 will be described. Corresponding to each electrode body 12a of one electrode 12 being arranged in a dot shape on the surface of the substrate 11, the other electrode 13 is not in contact with each electrode body 12a. Further, a conductive material 17 layer is formed on the surface of the substrate 11 so as to surround each electrode main body 12a. That is, the other electrode 13 is formed so as to surround each electrode main body 12 a on the same surface as the surface of the base 11 on which the electrode main body 12 a of one electrode 12 is provided on the surface of the base 11. The peripheral portion of the other electrode 13 functions as a connection portion 13d with an external wiring.

Organic semiconductors 14 and 15 are provided on one electrode 12 and the other electrode 13 formed in such an electrode structure. In the embodiment shown in FIG. 1, a p-layer organic semiconductor 14 is formed on the electrode body 12 a of one electrode 12, and an n-layer organic semiconductor 15 is formed on the other electrode 13. . Therefore, the electrode body 12a of one electrode 12 functions as a p-type electrode, and the portion covered with the n-type organic semiconductor 15 of the other electrode 13 functions as an n-type electrode.

Contrary to the configuration shown in FIG. 1, although not shown, an n-layer organic semiconductor is formed on the electrode body 12 a of one electrode 12, and a p-layer organic semiconductor is formed on the other electrode 13. It may be formed. In this embodiment, the electrode body 12a of one electrode 12 functions as an n-type electrode, and the portion of the other electrode 13 covered with the p-type organic semiconductor functions as a p-type electrode.

The p-layer organic semiconductor 15 is formed of a hole transport material. As a hole transport material, in addition to triphenylamine (TAPC) represented by the chemical formula (1), TPD and other aromatic amines which are dimers of triphenylamine represented by the chemical formula (2), the chemical formula (3) Α-NPD represented by formula (4), (DTP) DPPD represented by formula (4), m-MTDATA represented by formula (5), HTM1 represented by formula (6), 2-TNATA represented by formula (7), TPTE1 represented by the chemical formula (8), TCTA represented by the chemical formula (9), NTPA represented by the chemical formula (10), spiro TAD represented by the chemical formula (11), TFREL represented by the chemical formula (12), and the like are used.

The n-layer organic semiconductor 14 is formed of an electron transport material. Examples of the electron transport material include Alq ₃ represented by the chemical formula (13), BCP represented by the chemical formula (14), an oxadiazole derivative represented by the chemical formula (15), and an oxadiazole dimer represented by the chemical formula (16). And Starbust Oxadiazole represented by Chemical Formula (17), Triazole Derivative represented by Chemical Formula (18), Phenylxoxaline Derivative represented by Chemical Formula (19), Silole Derivative represented by Chemical Formula (20), and the like.

The protective layer 16 is formed of a resin or the like, for example, as long as it is a material that transmits irradiation light such as sunlight.

A method for producing the photoelectric conversion device 1 shown in FIG. First, a plurality of through holes 11a are formed in a predetermined pattern in the base material.

Next, after the whole surface of the base material is plated by electroless plating on the base material with the through holes 11a, the metal on the part where one electrode and the other electrode are not formed is removed by etching or the like, and one electrode and the other A seed electrode is formed as a source of the electrode.

Then, if necessary, an electroplating process is performed by covering the mask, and the conductive material 17 is filled in the through hole 11a to form one electrode 12 and the other electrode 13. Note that one electrode and the other electrode may be formed by a printing method without using the plating process.

Thereafter, a hole transport material to be the p-layer organic semiconductor 14 is applied to a predetermined portion, for example, one electrode 12. For the application, for example, a printing method using an inkjet printer can be applied.

Next, an electron transport material to be the n-layer organic semiconductor 15 is applied between the p layer and the p layer, for example, the other electrode 13. As in the case of the p-layer organic semiconductor 14, a printing technique using an inkjet printer may be used for coating.

Thus, a pn junction is formed by the p-layer organic semiconductor 14 and the n-layer organic semiconductor 15. The n-layer organic semiconductor 15 may be applied, and then the p-layer organic semiconductor 14 may be applied.

Thereafter, the photoelectric conversion device 1 is manufactured by forming the protective layer 16 by painting or the like. Note that the method is not limited to the above-described method as long as the photoelectric conversion device 1 illustrated in FIG. 1 is manufactured.

The embodiment of the present invention may be appropriately changed depending on device performance, design, and the like.
For example, the pattern of the one electrode 12 and the other electrode 13 in plan view is not limited to that shown in FIG. 3 and can be changed as appropriate. In FIG. 3, the electrode body 12a of one electrode 12 is rectangular in plan view, but may be a triangle, polygon, circle, ellipse, or other geometric pattern.

FIG. 4 is a plan view showing a modification of the photoelectric conversion device electrode. In the base material 11, the through holes 11a are formed in a rhombus shape in plan view, the electrode main body portion 12a of one electrode 12 is formed in a rhombus shape, and the other electrode is formed as a pattern in which rhombus shapes similar to the electrode main body portion 12a are arranged in a matrix. May be. In this case, as in the above configuration example, it is a matter of course that one electrode 12 and the other electrode are separated from each other. In this way, the area of each electrode may be a geometric pattern that is uniform between the p-type electrode and the n-type electrode.

1: Photoelectric conversion device 11: Substrate 11a: Substrate through-hole 12: One electrode 12a: Electrode body (dot electrode)
12b: filling portion 12c: wiring electrode portion 12d: external connection portion 13: other electrode 13d: connection portion with external wiring 14: p-layer organic semiconductor 15: n-layer organic semiconductor 16: protective layer 17: conductive material 18 : Gap

Claims (7)

An insulating substrate having a plurality of through holes according to a pattern;
One electrode formed so as to be exposed on the surface of the base material while filling the through hole of the base material with a conductive material;
The other electrode provided so as to have a gap between the one electrode and the surface of the substrate;
An electrode for a photoelectric conversion device. The electrode for a photoelectric conversion device according to claim 1, wherein the one electrode is connected to each other by a conductive film formed on a back surface of the base material. The electrode for a photoelectric conversion device according to claim 1, wherein the one electrode has a protruding portion protruding from the surface of the base material. The electrode for a photoelectric conversion device according to claim 1, wherein the one electrode and the other electrode are formed of Cu or Al. 5. The optoelectronic device electrode according to claim 1, wherein a p-layer organic semiconductor made of a hole transport material is provided on the one electrode, and an electron is provided on the other electrode. An n-layer organic semiconductor made of a transport material is provided, and the p-layer organic semiconductor and the n-layer organic semiconductor are alternately formed on the same surface. 5. The optoelectronic device electrode according to claim 1, wherein an n-layer organic semiconductor made of an electron transport material is provided on the one electrode, and a hole is formed on the other electrode. A photoelectric conversion device comprising a p-layer organic semiconductor made of a transport material, wherein the p-layer organic semiconductor and the n-layer organic semiconductor are alternately formed on the same surface. The photoelectric conversion device according to claim 5 or 6, wherein the organic semiconductor of the p layer and the organic semiconductor of the n layer are covered with a transparent protective layer.

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