JPS59197831A - Photoelectric converting element - Google Patents

Abstract

PURPOSE:To obtain a photoelectric converting element which generates photovoltaic power and is usable as various photodetecting elements by mixing a visible photosensitizing agent which can be reduced by photooxidation-with a medium which provides electrical conductivity and holding tightly the mixture composed thereof between prescribe elements in tight contact therewith. CONSTITUTION:A light layer 3 contg. a visible photosensitizing agent and a supporting electrolyte is held between an electrode 2 having light transmissivity and semiconductor characteristic and a counter electrode 4 thereof in tight contact therewith. More specifically, the soln. contg. the visible photosensitizing agent, the supporting electrolyte and an org. high polymer is directly coated on, for example, the one electrode than the electrode contrasting therewith is superposed on the coated layer, by which the element is formed. The visible photosensitizing agent may be any photosensitizing agent that has a function as a photosensitizing catalyst involving photooxidation reduction- like electron movement using the boundary with a semiconductor as an electric charge separating material. The supporting electrolyte of the case in which the visible photosensitizing agent is used by being mixed with a high polymer mterial is enumerated by tetrabutyl ammonium perchlorate, lithium perchlorate, tetraethyl ammonium perchlorate, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoelectric conversion element. More specifically, the invention is a photoelectric conversion element composed of three layers: (a) a semiconductor electrode, (b) a visible light sensitizer with photoredox properties, a medium imparting electrical conductivity, and (C) a counter electrode. The present invention relates to photoelectric conversion elements useful as various photodetection elements such as organic solar cells and detection elements responsive to flash light.

Conventionally, when producing photoactive electrodes such as photoelectric conversion elements, a thin layer of a photo-redox sensitizer such as a dye is applied to a light-transmitting electrode such as a thin metal film or a thin metal oxide film. Various forming methods have been proposed. Specifically, methods have been used in which porous electrodes are impregnated with it, or it is formed into a monomolecular film, which is then coated or steamed.
However, the drawbacks of such methods are (1) What about impregnation and adsorption methods? 1f, the electrode must be porous and it is difficult to apply it to electrodes that cannot be made porous (2
) The method of forming a monomolecular film and applying it requires the separate synthesis of a sensitizing compound that can be formed into a monomolecular film, and (3) The vapor deposition method requires long-term vacuum heating. There are constraints such as complexity and time required.

The invention of wood was made in consideration of several such problems.

Thus, the present invention [, 1: According to the present invention, a layer consisting of a visible light sensitizer having photo-oxidation-reduction properties and a medium imparting electrical conductivity is directly held in close contact between a pair of opposing electrodes. Provided is a photoelectric conversion element characterized in that, of the pair of electrodes, the electrode located on the light irradiation side is light-transmissive and has semiconductor characteristics.

The invention lies in the discovery that a photovoltaic force can be generated simply by mixing a photo-redox visible light sensitizer with a medium that imparts electrical conductivity and directly holding the mixture between predetermined electrodes. The medium that imparts electrical conductivity may itself be electrically conductive, or may be a medium that promotes the electrical conductivity of the sensitizer. It may be a single material such as graphite or a conductive polymer, or it may be a mixture such as a solution of a general polymeric material in an organic solvent and a supporting electrolyte as described in the Examples. Since adhesion with the electrode is required, the mixture of the photoredox visible light sensitizer and the medium imparting electrical conductivity may be dissolved in a solvent (which may be volatile or nonvolatile) if necessary. It is best to use it in liquid form. The solvent may be volatilized or may be allowed to exist between the electrodes in a liquid state.

In the production of the photoactive electrode of the photoelectric conversion device of the invention, in particular when using a polymer solution layer containing a photoredox visible light sensitizer and a supporting electrolyte, optionally, for example, a phototransparent semiconductor may be used. It can be easily formed by directly coating on the electrode, and the strength of bonding to the electrode can be adjusted by selecting the polymer. Furthermore, since it basically consists of three layers, no complicated process is required. Therefore, it is extremely advantageous compared to conventional photoelectric conversion elements, which require complicated and time-consuming manufacturing processes.

Visible f in this invention, %4%! Any material that functions as a photosensitizing catalyst through photoredox electron transfer to Jt may be used, and so-called organic dyes are used.

For example, tetra(4-N-alkylpyridine)povolphyrin and its zinc complex, organometallic complexes such as 4-sulfophenylporphyrin zinc complex, xanthine dyes such as uranine, eosin, erythrosine, fluorescein, rose bengal, and rhodamine B, methylene blue, Thiazine color E such as thionine, 4,4'-cyanine, quinoline blue, binachrome, ethyl V-tude, pseudocyanine, binaperdol, orthofrom, phthalocyanine,
Cyanine dyes such as merocyanine, dienylboriene dyes such as 1 + 2-diphenylethylene, proflavin 2,7.9-trimethyl-3,6-diamitacridine, 2゜7-cymethoxy 8.6- These include acridine dyes such as diamitacridine, triphenylmethane dyes such as malachite green, and fast aromatic hydrocarbons such as tetracene.

When a visible light sensitizer is used in combination with a polymeric material and a supporting electrolyte, examples of the supporting electrolyte include tetrabutylammonium perchlorate, lithium perchlorate, tetraethylammonium perchlorate, tetrabutylammonium bromide, etc. Can be mentioned. In addition to these, various electrolytes that can be dissolved in the stone solvent as described later can be applied.

Furthermore, when using the same phase, it is preferable to add a substance that exhibits conductivity even in a solid state, such as copper iodide.

Further, the polymer material used is preferably a low-resistance material that allows smooth electron transfer, but is not limited thereto.

Usually, for example, hydroxyl group, ester group, organic acid group, cyan group,
Polymers containing amino groups or the like in their hydrocarbon chains or ionic polymers can be used.

The device of the present invention is formed by directly applying a solution containing such a visible light sensitizer, supporting electrolyte, and organic polymer to one electrode, and then overlaying the corresponding electrode on this applied layer. As the solvent in this case, it is appropriate to use a solvent that can dissolve the above-mentioned organic polymer, supporting electrolyte, and visible light sensitizer, and usually dimethylformamide (
Various organic solvents can be used, such as DMF), dimethyl sulfoxide (DMSO), and tetrahydrofuran. Note that, in practice, it is preferable to seal the periphery of the liquid layer that is held in close contact with an adhesive or the like, but there is no particular need for sealing when it is dried to form a solid phase.

As mentioned above, the layer between the two electrodes may be in a liquid or solid state, and its thickness is not particularly limited.It goes without saying that it does not need to be thin, and it can be made thick, but it is possible to When constructed from a flexible material, it is preferable to maintain flexibility as a whole by setting d l to about 1 m in order to take advantage of its characteristics. The concentration of visible light sensitizer is 0-01 mM/
Approximately 1 to 100 mM71 is suitable, but there is no particular restriction.

When using the above visible light sensitizer, supporting electrolyte, and polymeric material, it is usually convenient to use them as a mixture; Contained in the form of a polymeric material containing a chain), a mixture of a polymeric material containing a visible light sensitizer as a molecular structure and an electrolyte, or a mixture of a polymeric material containing an electrolyte as a molecular structure and a visible light sensitizer. may have been done.

On the other hand, the electrode located on the light irradiation side of the pair of electrodes in the present invention is required to be an electrode that is transparent to light and has semiconductor properties. When a light-transmitting electrode such as a metal thin film is used on the light irradiation side, the photoelectric conversion effect is low and it is not suitable. ′
This is considered to be due to the unique photoelectron transfer caused by the combination of the intermediate layer and electrode of the present invention. Examples of such electrodes include metal oxide thin films, more specifically tin oxide, indium oxide, tin oxide-indium thin films, or zinc oxide deposited on the surface of a glass substrate or polymer film. The thin film opens and rubs. Usually steamed onto a polymer film! What you did is nice.

In addition, as an electrode opposite to the above-mentioned electrode, various nl: electrodes may be mentioned, and a metal thin film electrode may be used, or a semiconductor electrode may be used. It is also appropriate to use these in the form of vapor deposition on the surface of a glass substrate or polymer film.

By light irradiation, an open circuit photovoltaic voltage is generated between the two poles of the photoelectric conversion element, and a photocurrent is obtained by applying a load between the two poles and short-circuiting them externally.

The following appendix together with the first page describes an embodiment of the invention.

Examples 1 to 3 FIG. 1 is a sectional view showing an example of the photoelectric conversion element of the present invention. In the figure, a visible light sensitizer, tetra(4-N-methylpyridine)porphyrin zinc complex (hereinafter abbreviated as ZnTMP7P), is placed between an electrode (2) that is transparent and has semiconductor properties and its counter electrode (4). Tetrabutylammonium barchlorate (hereinafter referred to as TBA) as a supporting electrolyte
A DMF solution layer (3) of polyacrylonitrile containing polyacrylonitrile (abbreviated as P) is held in close contact.

On the other hand, a vapor-deposited film of indium-tin oxide (hereinafter abbreviated as TO) is used on the polyester film (1) as the light-transmissive semiconductor electrode (2), and a semiconductor (for example, TO) or metal is used as the counter electrode (4). (For example, gold) was deposited on a polyester film (one film was used).CELFiO (trade name of Daicel Chemical Industries, Ltd.) was used as the deposited film.

In addition, the liquid layer (3) was formed by applying a DMF solution containing a visible light sensitizer, a supporting electrolyte, and an organic polymer onto the electrode (2), and then stacking the electrode (4) on top of it to maintain close contact (
Layer thickness g, 13 m, light receiving surface 20 x 30 Mr II).

Table 1 shows the intensity of photocurrent due to these semiconductor power outages and the combinations of poles and counter electrodes.

Example 2 is the same as Example 1, using rose bengal instead of ZnTMPyP, and Example 8 is the same as using methylene blue.

The results are also listed in Table 1.

In such an invention, ZnTMPyP produces a photoresponse by exhibiting a function as a visible light sensitizer through oxidative electron transfer using the ITO interface as a charge separation field. In addition, when the light irradiation fine electrode is made of a metal vapor-deposited film, the light current 'i1' decreases significantly even if To is used as the counter electrode. When both electrodes were made of metal and when an organometallic complex was added, the light weight per current was 0. These are also listed in Table 1 as reference examples.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of the photoelectric conversion element of the present invention. (1) (1') - Polyester film, (2)
Electrode that is optically transparent and has semiconductor properties, (3)...-liquid layer, (4)...counter electrode. Figure 1

Claims (1)

[Claims] 1. A layer consisting of a visible light sensitizer having photooxidation-reduction properties and a medium imparting electrical conductivity is directly and closely held between a pair of opposing electrodes; A photoelectric conversion element characterized in that among the electrodes, the electrode positioned on the side facing the light is transparent and has semiconductor properties. 2. The photoelectric conversion element according to claim 1, wherein the light-transmitting electrode having semiconductor properties is indium-tin oxide. 3. The photoelectric conversion element according to claim 1, wherein the visible light sensitizer having photoredox properties is an organometallic complex. 4. The photoelectric conversion device according to claim 3, wherein the organometallic complex is a tetra(4-N-alkylpyridine)porphyrin zinc complex. 5. The photoelectric conversion element according to claim 1, wherein the pair of opposing electrodes are each formed on a plastic film by vapor deposition.