JPH04109682A - Organic solar battery - Google Patents

Abstract

PURPOSE:To realize high energy conversion efficiency and stabilize performance by providing, between a transparent electrode and an opposed electrode, a first layer consisting of perylene pigment, a second layer consisting of phthalocyanine pigment and a third layer consisting of quinacridone pigment from the transparent electrode side. CONSTITUTION:A multilayered film in which a first layer is formed of perylene pigment, a second layer consisting of phthalocyanine pigment and a third layer consisting of quinacridone pigment are build up on the first layer is provided between electrodes. Thereby, a uniform film having no pinhole can be formed, electrodes are not short-cirucitted and total performance can be stabilized. Since the second layer consisting of phthalocyanine pigment is provided to generate a high electromotive force, high energy conversion efficiency can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an organic solar cell, and more particularly to an organic solar cell in which a layer mainly composed of an organic compound is provided between a transparent electrode and a counter electrode.

(Conventional technology) Organic solar cells that use organic compounds as solar cell materials are superior to solar cells that use inorganic semiconductors in terms of cost, large area, and ease of manufacturing process, and are more cost effective than conventional solar cells. Organic solar cells of various configurations using organic compounds as solar cell materials have been proposed.

For example, an organic solar cell using a laminated film of copper phthalocyanine and perylene dye has been proposed, and the energy conversion efficiency of this organic solar cell is reported to be about 1% (C, W, Tang, Applied Phys.
ics Letters, Vol. 48. p. 183)
+1 However, in the solar cell described above, in order to obtain high energy conversion efficiency, the thickness of the dye layer, which is a semiconductor layer, must be thin. As a result, pinholes are likely to form in the film, resulting in short circuits between the electrodes.

On the other hand, a Schottky type solar cell using a quinacridone dye is called CHEMISTRY LETT.
ER5 (1984) P, 1305, Proceedings of the Society of Polymer Science, Vol. 34 (1985), p. 2001, JP-A-61-5978
It is described in Publication No. 4. In these solar cells, a method is used to form a Schottky junction by laminating a metal with a low work function such as indium or aluminum on the dye layer, and these metal films are formed using methods such as vapor deposition or sputtering. However, it has the drawback that oxygen in the air tends to form an oxide film on the bonding interface, deteriorating the bond and reducing performance. Furthermore, since light must be incident from the side of a metal electrode such as indium or aluminum, there is a drawback that the low light transmittance of the metal leads to a decrease in energy conversion efficiency.

(Problems to be Solved by the Invention) The present invention has been made in order to solve the above-mentioned drawbacks, and its purpose is to provide an organic solar cell with high energy conversion efficiency and stable performance with few electrode short circuits. The goal is to provide batteries.

(Means for Solving the Problem) The transparent electrode used in the present invention is formed using a known electrode material that can transmit visible light, and is usually formed by vacuum evaporation, sputtering, ionization, etc. on the surface of a transparent substrate. Provided by brating or the like.

The above electrode material is not particularly limited as long as it has a small effect on the characteristics of the organic solar cell, for example,
Examples include semiconductors and metals such as tin-doped indium oxide (hereinafter referred to as ITO), tin oxide, and indium oxide. In order to inject light particularly efficiently,
ITO, which has low absorption of visible light, is preferably used.

Examples of the transparent substrate include glass and polymers such as acrylic, vinyl, polyolefin, polyester, polyamide, and polycarbonate.

The counter electrode used in the present invention is formed by vacuum evaporation, sputtering, ion blating, etc. using a known electrode material.

Examples of the electrode material include metals with a large work function such as gold, silver, and platinum.

The perylene dye used in the first layer of the present invention includes:
Examples include bisbenzimidazur perylenetetracarboxylate, N,N'-dimethylperylenetetracarboxylic acid diimide, N,N'-diphenylperylenetetracarboxylic acid diimide, etc. These may be used alone or in combination of two or more. be done.

An example of a method for forming the first layer is a vacuum evaporation method in which perylene dye is sublimated by resistance heating in a vacuum container.

The film thickness of the first layer is not particularly limited, but as it becomes thinner, pinholes are more likely to occur, and as it becomes thicker, energy conversion efficiency decreases due to a decrease in light transmittance and an increase in the electrical resistance of the film. Therefore, 500 to 3000 people is preferable.

Examples of the phthalocyanine dye used in the twenty-first aspect of the present invention include metal-free phthalocyanine, metal phthalocyanine, and derivatives thereof.

Examples of the metal phthalocyanine include copper, magnesium, zinc, aluminum, tin, chromium, manganese, iron, cobalt, rhodium, palladium,
Examples include metal phthalocyanine compounds formed from metals such as platinum, halides of metals having a valence of 3 or more.

Examples of the above derivatives include derivatives in which a hydrogen atom in a phthalocyanine molecule is substituted with a sulfone group, a nitro group, a cyano group, a carboxyl group, a halogen atom, or the like.

As a method for forming the second layer, for example, as in the case of the first eyebrow, a vacuum evaporation method can be mentioned.

The second rI can generate a sufficient electromotive force even in a very thin film, and the same effect can be achieved even if the film has pinholes or is discontinuous. do. The thickness of the film is not particularly limited, but if it becomes thin, it will not be able to generate sufficient electromotive force.
The number of people is preferably 20 to 100, since the thicker the layer, the greater the absorption of light and the lower the energy conversion efficiency.

Examples of the quinacridone dye used in the third layer of the present invention include unsubstituted quinacridone, 2.9-dimethylquinacridone, 2.9-dichloroquinacridone, 3. IO
-dimethylquinacridone, 3,1O-dichloroquinacridone, 4,11-dimethylquinacridone, etc.
These may be used alone or in combination of two or more.

As a method for forming the third layer, for example, a vacuum evaporation method may be used as in the case of the above-described third layer.

The thickness of the third layer is not particularly limited, but as it becomes thinner, pinholes are more likely to occur, and as it becomes thicker, the electrical resistance of the film increases and the energy conversion efficiency decreases. People are preferred.

(Example) Hereinafter, the present invention will be explained by examples.

The transparent conductive glass substrate on which ITO was deposited was placed in a vacuum container of a vacuum evaporation device, and the pressure was reduced to 1 × 10-horr.
, N'-dimethylperylenetetracarboxylic acid diimide was resistively heated and deposited to a thickness of 1500 nm on the ITO film.

Next, on this film, metal-free phthalocyanine and 2,9-dimethylquinacridone were sequentially added for 30 minutes in the same manner as N,N'-dimethylperylenetetracarboxylic acid diimide.
A vacuum jacket with a thickness of 1,500 people was worn.

Finally, lXl0-'Tor
Gold was vacuum deposited under a reduced pressure of r, and the thickness of 3
An organic solar cell was obtained by forming a counter electrode with a thickness of 0.00 mm.

The photoelectric conversion characteristics of the obtained organic solar cell were as follows: under irradiation with AM2 light (75 mW/c+11) from the IT○ transparent electrode side, the energy conversion efficiency was 0.15%, and the open circuit voltage was 0.3.
The voltage was 8V, the current density was 0, 56 mA/c+1, and the fill factor was 0.51.

In addition, in Example 1, except that chloro(phthalocyanine) aluminum was used instead of metal-free phthalocyanine,
An organic solar cell was obtained in the same manner as in Example 1.

The photoelectric conversion characteristics of the obtained organic solar cell were as follows: under irradiation with AM2 light (75 mW/c4) from the ITO transparent electrode side, the energy conversion efficiency was 0.18%, and the open circuit voltage was 0.40.
V, current density was 0, 91 mA/cffl, and fill factor was 0.37.

An organic solar cell was obtained in the same manner as in Example 1, except that unsubstituted quinacridone was used instead of 2,9-dimethylquinacridone.

The photoelectric conversion characteristics of the obtained organic solar cell were as follows: under the irradiation of AM2 light (75 mW/cJ) on the ITO transparent side electrode side, the energy conversion efficiency was 0.19%, the open circuit voltage was 0.42 V,
Current density 0.80a+A/cm, fill factor 0.
It was 40.

An organic solar cell was obtained in the same manner as in Example 1 except that the metal-free phthalocyanine layer was removed.

The photoelectric conversion characteristics of the obtained organic solar cell were ITOi! !
Under irradiation with AM2 light (75 mlj/d) from the bright electrode side, energy conversion efficiency was 0.06% and open circuit voltage was 0.35.
V, current density was 0, 21 mA/cd, and fill factor was 0.56.

Comparison ±1 In Example 3, an organic solar cell was obtained in the same manner as in Example 1, except that the metal-free phthalocyanine layer was removed.

The photoelectric conversion characteristics of the obtained organic solar cell were determined under the irradiation of AM2 light (75a+W/cm) from the IT0 transparent electrode side.
Energy conversion efficiency 0.08%, open end voltage 0.48V
, the flow density was 0, 30 mA/c (and the fill factor was 0.41).

(Effects of the Invention) In the organic solar cell of the present invention, the first layer is formed of a perylene dye, and the second layer made of a phthalocyanine dye and the third layer made of a quinacridone dye are sequentially formed on the first JIO. Since the laminated material is provided between the electrodes, it is possible to form a uniform film with fewer pinholes compared to conventional organic solar cells in which only dye is provided between the electrodes. It becomes possible to produce organic solar cells with stable performance and no short circuits. Furthermore, by providing a second layer made of a phthalocyanine dye that can generate a high electromotive force between the first perylene dye layer and the 3N quinacridone dye layer, the conventional two-layer structure is improved. Compared to solar cells, higher energy conversion efficiency can be obtained.

Claims (1)

[Claims] 1. A first layer made of a perylene dye, a second layer made of a phthalocyanine dye, and a third layer made of a quinacridone dye are sequentially provided from the transparent electrode side between the transparent electrode and the counter electrode. organic solar cells