JPH1051049A - Method of controlling moving direction of electrons in photoenergy conversion system using coloring matter, and photoenergy convertor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with the surface processing of an electrode, etc., and besides, control the moving direction of electrons by coloring matter alone. SOLUTION: Coloring matter S which absorbs photoenergy and discharges and absorbs electrons is fixed to a substrate 10 which performs the transfer of the coloring matter S and electrons, and the coloring matter is irradiated with photoenergy to induce the motion of electrons in desired direction. In this case, the moving direction of the electrons is controlled by changing the number of carbons of an alkyl group 20 to be coupled with the coloring matter S.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the moving direction of electrons in a light energy conversion system using a dye such as a porphyrin derivative, and a light energy conversion device using the same.

[0002]

2. Description of the Related Art Conventionally, many studies have been made on a light energy conversion system that performs photoelectric conversion by immobilizing a dye on an electrode surface. In such a light energy conversion system, when the dye that has absorbed light injects electrons into the electrode,
When an anodic current is generated and, on the contrary, the dye that has absorbed light robbs electrons from the electrode, a cathodic current is generated.

As a method for controlling the direction of the generated photocurrent, as shown in FIG. 7, a dye S which absorbs light energy and emits electrons is combined with an electron mediator M which plays a role of receiving the electrons. A method of controlling the direction of photocurrent by controlling the direction of the molecule on the electrode surface by using a compound that has been made to react (M. Fujihira et. Al. Thin Soli) is known.
d Films, 132 (1985) 77).

[0004] Since the electron transfer from the dye S to the electron mediator M becomes a driving force to generate a current, the direction of the photocurrent flows from the electron mediator M to the dye S. That is, when the dye S is in contact with the surface of the electrode substrate 1, a cathode current (FIG. 7A) flows, and when the electron mediator M is in contact with the surface of the electrode substrate 1, An anode current (FIG. 7B) flows. As a method of controlling the orientation of the molecule in this case,
Generally, the LB method is used.

However, it is difficult to orient the molecules in the intended direction only by the LB method. The reason is the influence of the environment on the electrode surface. For example, in the case where the electrode surface is hydrophilic, it is difficult to orient the molecules having high hydrophobicity to be accumulated toward the electrode surface side by using the LB method. In this case, it is necessary to perform a hydrophobic treatment on the electrode surface to make the electrode surface hydrophobic.

As described above, when trying to control the direction of the photocurrent (the moving direction of the electrons), it was necessary to combine the LB method with the treatment of the electrode surface. Further, a molecule in which a dye and an electron mediator are bonded must be used, and the direction of the photocurrent cannot be controlled by the dye alone.

[0007]

As described above, in the prior art, when the direction of movement of electrons (direction of photocurrent) in a light energy conversion system using a dye is controlled, the LB method and the electrode are used. It had to be combined with a surface treatment, and a molecule in which a dye and an electron mediator were combined had to be used.

The present invention has been made in view of such a conventional situation, and does not require a surface treatment of an electrode or the like, and uses a dye capable of controlling a moving direction of electrons by a dye alone. It is an object of the present invention to provide a method for controlling the moving direction of electrons in a conversion system and a light energy conversion device using the method.

[0009]

According to the first aspect of the present invention, a dye that absorbs light energy to emit and absorb electrons is provided.
The dye is immobilized on a substrate that exchanges electrons with the dye, and when the dye is irradiated with light energy to cause the electron to move in a desired moving direction, the electron moving direction is changed to an alkyl group to be bonded to the dye. It is characterized in that it is controlled by changing the number of carbon atoms.

According to a second aspect of the present invention, a dye that absorbs light energy and emits and absorbs electrons is fixed to a substrate in a predetermined direction, and the dye is irradiated with light energy to emit electrons in a desired moving direction. In producing the transfer, the direction in which the dye is immobilized on the substrate is controlled by changing the carbon number of the alkyl group bonded to the dye.

The invention according to claim 3 is characterized in that any one of a porphyrin derivative, a ruthenium bipyridine complex derivative, a pyrene derivative, a phthalocyanine derivative, merocyanine, methylene blue, and thionin is used as the dye.

The invention of claim 4 is characterized in that an alkyl porphyrin is used as the dye.

The invention according to claim 5 is characterized in that the dye is immobilized on the substrate by an LB method.

According to a sixth aspect of the present invention, the base is a conductive substrate or platinum, ruthenium dioxide, gold, tin oxide,
It is characterized by including at least a catalyst made of palladium.

According to a seventh aspect of the present invention, a dye that absorbs light energy and emits and absorbs electrons is fixed to a substrate in a predetermined direction, and the dye is irradiated with light energy to emit electrons in a desired moving direction. A light energy conversion device that causes the movement of the dye, wherein the direction in which the dye is fixed to the substrate is controlled by changing the number of carbon atoms of the alkyl group bonded to the dye.

The invention according to claim 8 is characterized in that the substrate is a conductive substrate, and the dye is irradiated with light energy to cause electrons to move in a desired moving direction to generate a current.

According to a ninth aspect of the present invention, the substrate is a substrate on which a catalyst or a catalyst layer is formed, and the dye is irradiated with light energy to cause movement of electrons in a desired moving direction, thereby causing a chemical reaction. It is characterized by making it.

The invention according to claim 10 is characterized in that the catalyst or the catalyst layer is made of any of platinum, ruthenium dioxide, gold, tin oxide and palladium.

[0019] The invention of claim 11 is a method for producing a porphyrin derivative, a ruthenium bipyridine complex derivative,
Pyrene derivatives, phthalocyanine derivatives, merocyanines,
It is characterized by using either methylene blue or thionine.

A twelfth aspect of the present invention is characterized in that an alkylporphyrin is used as the dye.

[0021] The invention of claim 13 is characterized in that the dye is immobilized on the substrate by an LB method.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

The present inventors have been intensively studying a light energy conversion system using a dye, and in the light energy conversion system using such a dye, an alkyl group is bonded to the dye, It was found that the direction of electron transfer (current direction) can be controlled by changing the carbon number of the group.

The present invention is based on this finding, and controls the direction of electron transfer by changing the number of carbon atoms of an alkyl group bonded to a dye. FIG. 1 schematically shows the principle of the present invention. In FIG. 1, S represents a dye, 10 represents a substrate as a substrate, and 20 represents an alkyl group. In the present invention, the alkyl group 2 bonded to the dye S
By changing the number of carbon atoms of 0, the dye S is immobilized on the substrate 10 so that the dye S side faces (FIG. 1A), or immobilized on the substrate 10 so that the alkyl group 20 side faces (FIG. 1). (B)) is controlled.

When the substrate 10 is a conductive substrate (electrode) as shown in FIG. 2, by performing the above control, electrons are transferred from the substrate 10 to the dye S side as shown by arrows in FIG. A moving system (FIG. 2A) and a system in which electrons move from the dye S side to the substrate 10 side (FIG. 2B) are configured.

As the above dyes, for example, porphyrin derivatives, ruthenium bipyridine complex derivatives, pyrene derivatives, phthalocyanine derivatives, merocyanine, methylene blue, thionin, acridine yellow, proflavine, and the like can be suitably used.

As the dye, for example, the following formula (1)
When an alkyl porphyrin as shown in (1) is used, a product in which alkyl groups having various numbers of carbon chains (for example, 1 to 18) are bonded can be synthesized.

[0028]

Embedded image As a substrate for immobilizing the dye, for example, when performing photoelectric conversion, a conductive substrate, for example, gold, silver,
Gold, silver, copper, platinum, iron, aluminum on a conductive substrate made of copper, platinum, iron, aluminum, tin oxide, indium tin oxide, or a non-conductive substrate such as a transparent glass substrate or silica substrate A transparent metal substrate on which tin oxide or indium tin oxide is deposited or sputtered on a transparent glass substrate can be suitably used.

As a method for immobilizing a dye on the surface of the above-mentioned substrate (substrate), the Langmuir-Projet (LB) method can be suitably used. As a result, an LB film of the dye is formed on the surface of the substrate.

FIG. 3 schematically shows a main structure of a photovoltaic cell in which a dye-modified electrode having a dye S monomolecular film formed on the conductive substrate 10 by the LB method is used as a working electrode. In the case of this example, by changing the number of carbon atoms of the alkyl group 20, the direction of the current indicated by the arrow in the drawing can be changed to the anode current (the direction in which electrons enter the electrode from the dye S) or the cathode current (the electron moves from the electrode to the dye S). Direction).

When a chemical reaction (photochemical reaction) involving electron transfer such as photodecomposition of an organic substance or water is caused by using a catalyst, as a substrate, platinum, as shown in FIG.
FIG. 5 shows a substrate 31 on which a catalyst layer 30 made of a catalyst such as ruthenium dioxide, gold, tin oxide, or palladium is formed.
As shown in FIG. 6, the conductive substrate 10 and the catalyst 40, or as shown in FIG. 6, the catalyst particles 50 themselves can be used.

As the organic substance, an organic acid (for example,
Formic acid, acetic acid, propionic acid, lactic acid, ascorbic acid, butyric acid, etc.) compounds, amine compounds (eg, ethylenediamine tetraacetate, ethylenediamine, ethylenediamine-2-propionate, ethylenediamine hydrochloride, triethanolamine, triethylamine, etc.), sulfur compounds (Hydrogen sulfide, 2-mercaptoethanol, mercaptosuccinic acid,
Mercaptobutyric acid) can be used.

[0033]

Embodiments of the present invention will be described below.

Example 1 An alkylporphyrin represented by the above formula (1) was synthesized. The porphyrins having an alkyl group having 1, 4, 8, 12, or 18 carbon atoms were synthesized.

Each porphyrin monolayer was formed by a LB method on a conductive substrate having indium tin oxide deposited on a glass substrate surface. A three-electrode photovoltaic cell was prepared using this LB film-modified substrate as a working electrode, a platinum electrode as a counter electrode, a silver electrode as a reference electrode, and a 0.1 M aqueous sodium perchlorate solution as an aqueous electrolyte solution. When the working electrode of this photovoltaic cell was irradiated with light, when the carbon number of the alkyl group of the alkylporphyrin was 1, 4, or 8, a cathode current was generated.

On the other hand, when the alkyl group of the alkylporphyrin has 12 or 18 carbon atoms, an anodic current is generated. Thus, the direction of the generated current could be controlled only by changing the carbon number of the alkyl group.

Example 2 An alkylporphyrin represented by the above formula (1) was synthesized. The porphyrins having an alkyl group having 1, 4, 8, 12, or 18 carbon atoms were synthesized. Each porphyrin monomolecular film was formed by the LB method on a substrate obtained by sputtering a platinum catalyst on the surface of a glass substrate. This LB film-modified platinum catalyst substrate was
M was immersed in an aqueous solution of ethylenediaminetetraacetic acid / sodium and irradiated with light.

As a result, when the number of carbon atoms of the alkyl group of the alkylporphyrin was 1, 4, or 8, no hydrogen was generated. On the other hand, when the alkyl group of the alkylporphyrin has 12 or 18 carbon atoms, hydrogen is generated. Thus, only by changing the carbon number of the alkyl group, the direction in which electrons flow to the catalyst could be controlled.

[0039]

As described above, according to the present invention,
A method for controlling the direction of electron transfer in a light energy conversion system using a dye that does not require surface treatment of electrodes and the like, and that can control the direction of electron transfer with the dye alone, and a light energy conversion device using the same. Can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating the principle of the present invention.

FIG. 2 is a diagram schematically illustrating the principle of the present invention.

FIG. 3 is a diagram schematically illustrating an embodiment of the present invention.

FIG. 4 is a diagram schematically illustrating an embodiment of the present invention.

FIG. 5 is a diagram schematically illustrating an embodiment of the present invention.

FIG. 6 is a diagram schematically showing an embodiment of the present invention.

FIG. 7 is a diagram schematically showing a conventional technique.

[Explanation of symbols]

 S: dye 10: substrate 20: alkyl group

Claims (13)

[Claims] 1. A dye that absorbs light energy and emits and absorbs electrons is immobilized on a substrate that exchanges electrons with the dye, and the dye is irradiated with light energy to move electrons in a desired moving direction. The method of controlling the moving direction of electrons in a light energy conversion system using a dye, wherein the moving direction of electrons is controlled by changing the number of carbon atoms of an alkyl group bonded to the dye. . 2. A dye that absorbs light energy and emits and absorbs electrons is fixed to a substrate in a predetermined direction,
When irradiating the dye with light energy to cause electron transfer in a desired movement direction, by changing the number of carbon atoms of an alkyl group bonded to the dye, the direction in which the dye is fixed to the substrate is changed. A method for controlling a moving direction of electrons in a light energy conversion system using a dye, characterized by controlling. 3. A porphyrin derivative as the dye,
The method according to claim 1 or 2, wherein any one of a ruthenium bipyridine complex derivative, a pyrene derivative, a phthalocyanine derivative, merocyanine, methylene blue, and thionin is used. 4. The method for controlling the direction of electron transfer in a light energy conversion system using a dye according to claim 1, wherein an alkyl porphyrin is used as the dye. 5. The method according to claim 1, wherein the dye is fixed to the substrate by an LB method. 6. The dye according to claim 1, wherein the substrate comprises at least a conductive substrate or a catalyst comprising at least one of platinum, ruthenium dioxide, gold, tin oxide, and palladium. A method for controlling the moving direction of electrons in the light energy conversion system used. 7. A dye that absorbs light energy and emits and absorbs electrons is aligned in a predetermined direction and immobilized on a substrate.
A light energy conversion device that irradiates light energy to the dye to cause movement of electrons in a desired moving direction, wherein a carbon number of an alkyl group bonded to the dye is changed to provide the dye to the base. A light energy conversion device characterized in that the direction in which it is fixed is controlled. 8. The light according to claim 7, wherein the substrate is a conductive substrate, and the dye is irradiated with light energy to cause electrons to move in a desired moving direction to generate a current. Energy conversion device. 9. The method according to claim 1, wherein the substrate is a substrate on which a catalyst or a catalyst layer is formed, and the dye is irradiated with light energy to cause movement of electrons in a desired movement direction, thereby causing a chemical reaction. The light energy conversion device according to claim 7, wherein 10. The light energy conversion device according to claim 9, wherein the catalyst or the catalyst layer is made of one of platinum, ruthenium dioxide, gold, tin oxide, and palladium. 11. The pigment includes a porphyrin derivative, a ruthenium bipyridine complex derivative, a pyrene derivative,
The light energy conversion device according to claim 7, wherein any one of a phthalocyanine derivative, merocyanine, methylene blue, and thionin is used. 12. The light energy conversion device according to claim 7, wherein an alkylporphyrin is used as the dye. 13. The light energy conversion device according to claim 7, wherein the dye is fixed to the substrate by an LB method.