JPH05326994A - Photovoltaic element - Google Patents

Abstract

PURPOSE:To provide a photovoltaic element that has a wide range of a spectral sensitivity and affords a high conversion efficiency as an organic photovoltaic element. CONSTITUTION:A photovoltaic element contains two electrodes in which the electrode on a light incident side is at least translucent, and a double layer part consisting of an electron accepting organic substance layer and an electron donative organic substance layer which are successively arranged in that order at least from the light incident side. In this photovoltaic element, a perylene tetracarboxylic acid dialkyl imido pigment layer is sandwiched between the translucent electrode on the light entrance side and the electron accepting organic substance layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photovoltaic element useful as an optical sensor and the like.

[0002]

2. Description of the Related Art A lot of research has been conducted on photovoltaic devices using organic materials as active materials. The purpose is to develop an inexpensive and non-toxic photovoltaic element, which is difficult to achieve with single crystal, polycrystal, and amorphous Si.

Since a photovoltaic element is an element that converts light energy into electric energy (voltage × current), its conversion efficiency is a main evaluation target. The generation of photocurrent requires the presence of an internal electric field, but several device configurations are known as methods for generating an internal electric field. When organic substances are used as the active material, the best data of conversion efficiency in each known constitution are as follows.

1) Schottky junction or MIS type junction One that utilizes an internal electric field generated in a metal / semiconductor junction. As organic semiconductor materials, merocyanine dyes, phthalocyanine pigments, etc. have been reported. Conversion efficiency of 0.7% (V _OC = 1.2 V, J _SC = 1.8 mA / c) when white light of 78 mW / cm ² was irradiated to the Al / merocyanine / Ag element.
m ² , ff = 0.25) has been reported. [A. K.
Ghosh et al. Appl. Phys. 49,5982
(1978)]. Among the organic semiconductors used in this type of device, those having high conversion efficiency are limited to p-type. Therefore, an electrode material having a low work function such as Al, In, or Mg is used. These are easily oxidized.

2) Hetero pn junction using n-type inorganic semiconductor / p-type organic semiconductor junction A method utilizing an internal electric field generated when n-type inorganic semiconductor / p-type organic semiconductor is joined. CdS, Z as n-type material
nO or the like is used. Merocyanine dyes and phthalocyanines have been reported as p-type organic semiconductor materials. IT
O / electrodeposited CdS / chlorinated aluminum chlorophthalocyanine / Au device irradiated with 75 mW / cm ² of AM-2 light had a conversion efficiency of 0.22% (V _OC = 0.69 V, J _SC =
0.89 mA / cm ² , ff =. 029) is the best [A. Hor et al. Appl. Phys. Lett. , 4
2, 15 (1983)].

3) Utilizing organic / organic hetero pn junction A technique utilizing an electric field generated when an electron-accepting organic substance and an electron-donating organic substance are bonded.

Malachite green as the former organic matter,
Dyes such as methyl violet and pyrylium, and condensed polycyclic aromatic compounds such as flavanthuron and perylene pigments have been reported, and examples of the latter include phthalocyanine pigments and merocyanine dyes.

[0008] ITO / CuPc / perylene pigment / Ag 75 mW / cm conversion efficiency 0.95% at ² AM-2 light irradiation to the device _{(V OC = 0.45V, J SC} = 2.
3 mA / cm ² , ff = 0.65) has been reported [C. Tang appl. Phys. Lett. , 4
8, 183 (1986)]. This value is the highest in a photovoltaic device using an organic material. Further, Japanese Patent Publication No. 62-4871 by the same inventor shows that a conversion efficiency of 1% (V _OC = 0.44 V,
J _SC = 3.0 mA / cm ² , ff = 0.6) has been reported.

[0009]

The conversion efficiency of a photovoltaic element using an organic substance is lower than that using an inorganic semiconductor. The largest cause of this is low short circuit photocurrent (J _SC ). 75 mW / cm ^{2 for} a device with a conversion efficiency of 5%
Of at least 10 mA / cm ² for white light irradiation of
_SC is required. The aforementioned J _SC is much lower than that. The cause is low quantum efficiency and narrow spectral sensitivity wavelength range. The spectral sensitivity wavelength is preferably extended from 400 nm to as long a wavelength as possible, but many conventional examples are limited to a specific wavelength range.

In many cases, ff is small. It is said that one of the causes of the low ff is that the quantum efficiency exhibited by the organic semiconductor sharply decreases in a low electric field. Therefore, a configuration in which a strong internal electric field is generated so as not to cause such a decrease is preferable for improving ff. Furthermore, an element configuration in which the generated electric field can smoothly reach the electrode without an energy barrier increases ff. Although _VOC can be improved by achieving these, in the past, in many cases, sufficient consideration was not made in these points.

In addition, many of the reported organic photovoltaic devices also have a problem in terms of chemical stability of electrode materials.

The above-mentioned prior art is viewed from the above viewpoints.

1) Schottky junction or MIS type junction V _OC can be large, but since the metal material is used for the electrode, the light transmittance of the electrode is low. The actual light transmittance is at most 30%, usually around 10%. Also, these materials have poor oxidation resistance. Therefore, it is not possible to expect high conversion efficiency and stable characteristics with this element form.

2) Inorganic semiconductor / organic semiconductor hetero pn junction Since charge generation is mainly performed in the organic layer, the spectral sensitivity is limited. This is because the organic layer is usually formed of a single material, but there is currently no organic semiconductor having strong light absorption from 400 to 800 nm, for example. Therefore, with this element structure, although the problems of the light transmittance of the light incident electrode and the stability of the electrode can be solved, a high conversion efficiency cannot be expected because the spectral sensitivity region is narrow.

3) Organic / organic hetero pn junction Compared with the above two types of structures, it is the most desirable one at present. Light can be emitted from the transparent electrode, and since photocharges can be generated with two kinds of materials, the spectral sensitivity can be expanded. In fact, it was 45 in the Tang report above.
At 0 to 550 nm, perylene pigment, 550 to 700 n
It can be seen that electric charge is generated by copper phthalocyanine at m. Also, the fact that ff is larger than other element configurations means that
It is estimated that the generated internal electric field is large. But,
Tang's technology has the following drawbacks:

First, because the organic layer is thin (300
~ 500Å is desirable in the patent),
The probability of pinholes is high. In our experiment,
A relatively high probability of a short circuit between the two electrodes, possibly due to a pinhole, is observed. The electrode area in Tang's paper is 0.1 cm ² , which is the area (1 cm ²
If the above is required), the improvement of yield becomes a big problem.

The second problem is the electrode material. In his invention, the electrodes need to make ohmic contact with each organic layer. In the above-mentioned paper, it is written that V _OC decreases in a device structure in which the organic layer is inverted. This is presumably because the ohmic contact was damaged. However, the stability of the metal material becomes a problem in the structure in which ohmic contact is achieved. This is because a metal that can make contact with an electron-accepting organic substance needs to have a low work function. In fact
In, Ag, Sn, and Al are exemplified in the patent.
All of these are easily oxidized.

The object of the present invention is to use an electrode having a high light-transmitting property on the incident side, and to use an electrode material having a high stability. Further, as an organic photovoltaic element, the spectral sensitivity range is wide and It is to provide an element which gives high conversion efficiency.

[0019]

In order to achieve the above object, as a result of intensive studies, as a result, an electron-accepting organic material layer and an electron donor are provided between at least two incident light-side electrodes between two electrodes having at least light-transmitting side. In a photovoltaic device including a portion of two continuous organic organic material layers, by providing a perylenetetracarboxylic acid dialkylimide pigment layer between the incident light side transparent electrode and the electron-accepting organic material layer, It was found that an organic photovoltaic element having a wide spectral sensitivity range can provide high conversion characteristics, and the present invention has been completed.

That is, in the present invention, a portion composed of two continuous layers of at least an electron-accepting organic substance layer and an electron-donating organic substance layer from at least the incident light side between two electrodes having at least light transmitting properties on the incident light side. In a photovoltaic element including
A gist of a photovoltaic element is that a perylenetetracarboxylic acid dialkylimide pigment layer is provided between an incident light side transparent electrode and an electron-accepting organic material layer.

Examples of the structure of the photovoltaic element of the present invention are shown in FIGS.
Shown in.

Here, the support may be on the back electrode side.

As an embodiment in which the translucent n-type inorganic semiconductor layer of the present invention is inserted, there is one shown in FIGS.

The element structure of the present invention is characterized in that, between two electrodes having at least a light-transmitting property on the incident light side, at least two layers of an electron-accepting organic material layer and an electron-donating organic material layer are provided from the incident light side. In the photovoltaic device including the portion, a perylene tetracarboxylic acid dialkylimide pigment layer is provided between the incident light side translucent electrode and the electron accepting organic material layer. It was found that with this configuration, the spectral sensitivity range is expanded and a high conversion characteristic is obtained as compared with simply stacking an electron-accepting organic material layer and an electron-donating organic material layer. The conversion efficiency (n) of the photovoltaic element is represented by the following equation.

[0025]

[Equation 1]

In the above equation, V _OC is the voltage when open, J _SC
Is a current at the time of short circuit, and ff is a value showing a factor of a voltage-current curve at the time of light irradiation called a fill factor. Pin
Is the incident light energy.

In this device, J _SC is particularly improved among the factors of the conversion efficiency. Generally, in a photovoltaic device in which an electron-accepting organic compound layer and an electron-donating organic compound layer are laminated,
The quantum efficiency at each wavelength depends on the light absorption and photoconductivity of each layer, and the integrated value of this quantum efficiency and the incident light spectrum appears as J _SC . Therefore, how much light in a wide wavelength range is breathed at the interface between the electron-accepting organic material layer and the electron-donating organic material layer, and the photoconductive performance of each layer are particularly important. In the device of the present invention, at least the translucent electrode / perylenetetracarboxylic acid dialkylimide pigment layer / electron-accepting organic material layer / electron-donating organic material layer is laminated from at least the incident light side, and the perylenetetracarboxylic acid dialkylimide pigment layer is laminated. A photocurrent is generated due to the absorbed light, the quantum efficiency of 400 to 600 nm is increased, the spectral sensitivity region is widened, and J _SC is improved.

The reason why the photocurrent accompanied by the light absorbed by the above-mentioned perylenetetracarboxylic acid dialkylimide pigment layer is not yet known, but it is expected to be due to the following factors, for example. ..

(A) The light absorbed by the perylenetetracarboxylic acid dialkylimide pigment layer transferred energy to the electron-accepting organic material layer or the electron-donating organic material layer, and contributed to the generation of charges.

(B) Due to the light absorbed by the perylenetetracarboxylic acid dialkylimide pigment layer, excitons generated therein move to the junction interface between the electron-accepting organic material layer and the electron-donating organic material layer, and an electric charge is generated.

(C) A bond can be formed between the perylenetetracarboxylic acid dialkylimide pigment layer and the electron-accepting organic compound layer, so that a high internal electric field is generated at the interface, and as a result, the perylenetetracarboxylic acid dialkylimide pigment layer /
Charges are now generated at both the electron-accepting organic material layer / electron-donating organic material layer interface.

The perylenetetracarboxylic acid dialkylimide pigment layer used in the present invention includes perylenetetracarboxylic acid dimethylimide pigment, perylenetetracarboxylic acid diethylimide pigment, perylenetetracarboxylic acid dipropylimide pigment, and perylenetetracarboxylic acid dibutylimide. Examples include pigments.

A suitable thickness of this layer is 50 to 3000 liters, and it is formed by a method such as vapor deposition, spin coating and dipping. Among these, vapor deposition is preferable for thinning and uniforming.

Further, due to the presence of the n-type inorganic semiconductor layer,
The improvement of V _OC , J _SC , and ff achieves the improvement of conversion efficiency and the reduction of short circuit. Although the reason why such an effect occurs is not exactly known, the following can be considered.

1) Improvement of conversion efficiency a) A material having a low Fermi level such as ITO is usually used for the transparent electrode. Therefore, when there is no n-type inorganic semiconductor layer, a Schottky junction is formed between the electron-accepting organic compound layer and the transparent electrode. This junction acts as an energy barrier when electrons move from the electron-accepting organic material layer to the transparent electrode. When the n-type inorganic semiconductor layer is present,
The contact of the transparent electrode / n-type inorganic semiconductor layer and the contact of the n-type inorganic semiconductor layer / electron-accepting organic material layer each achieve ohmic contact, so that the electron transfer is smooth.

B) Since the probability of short circuit can be reduced, the thinning of the organic layer is achieved and the quantum efficiency is improved.

C) Electrons are supplied from the n-type inorganic semiconductor layer to the electron-accepting organic compound layer in the dark, and the internal electric field strength generated at the interface between the electron-accepting organic compound layer and the electron-donating organic compound layer is enhanced.

2) Reduction of short circuit a) Step difference at the edge portion of the transparent electrode layer (1 when ITO is used)
However, the presence of the n-type inorganic semiconductor layer becomes gradual, and the probability of short circuit between both electrodes at this portion is reduced.

B) For example, even if a pinhole is present in the electron-accepting organic compound layer, the electron-donating organic compound layer in contact with the pinhole is n
A pn junction is formed with the type inorganic semiconductor layer to eliminate the effect of pinholes in the electron-accepting organic material layer. Similar effects occur between the back electrode and the electron-accepting organic material layer when pinholes are present in the electron-donating organic material layer. Therefore, it becomes difficult to observe a short circuit.

Next, various materials, film thicknesses and the like used in the photovoltaic element of the present invention will be described.

As the transparent insulating support used in the present invention, glass, plastic film or the like is used.

As the transparent electrode used in the present invention, indium tin oxide (ITO), tin oxide, indium oxide or the like is used. Preferred thickness is 100-10
It is 000Å.

The translucent n-type inorganic semiconductor layer used in the present invention comprises zinc oxide, zinc oxide doped with a trivalent metal, Cds, titanium oxide, amorphous silicon doped with phosphorus, etc., and zinc oxide, Cds. Etc. are preferred. The layer thickness is preferably 10 to 10000Å.

The electron-accepting organic material layer used in the present invention includes the above-mentioned perylenetetracarboxylic acid diphenylimide pigment and perylenetetracarboxylic acid bis (3,5-
Perylenetetracarboxylic acid diarylimide pigments such as dimethylphenyl) imide pigments and perylenetetracarboxylic acid bis (3-chlorophenyl) imide pigments Perylenetetracarboxylic acid diimidazole pigments flavanthron such as perylenetetracarboxylic acid diphenylimidazole pigments
Bromanthanthrone and other polycyclic quinone pigments, anthraquinone acridone pigments, naphthalene tetracarboxylic acid diimidazole pigments, crystal violet, methyl violet, malachite green dyes 2, 4, 7-
Trinitrofluorenone, tetracyanoquinodimethane,
Acceptors such as tetracyanoethylene and diphenoquinone These are deposited by vapor deposition, spin coating or dipping. Vapor deposition is preferred for thinning and uniforming.

The film thickness of the electron-accepting organic compound layer (I) of the present invention is preferably 50 to 3000 Å.

The electron-donating organic compound layers (I) and (II) used in the present invention include phthalocyanine pigments (having a central metal of Cu, Zn, Co, Ni, Pb, Pt, Fe, M).
trivalent metal phthalocyanine, chlorinated copper phthalocyanine, and chlorinated zinc phthalocyanine, to which a halogen atom is coordinated, such as divalent compounds such as g, metal-free phthalocyanine, aluminum chlorophthalocyanine, indium chlorophthalocyanine, indium bromophthalocyanine, gallium chlorophthalocyanine, etc. , Other, oxygen-coordinated phthalocyanines such as vanadyl phthalocyanine, titanyl phthalocyanine, rare earth diphthalocyanines, naphthalocyanines, indigo, thioindigo pigments (PigmentBlue)
66, Pigment Violet 36, etc.), quinacridone-based pigment (Pigment Violet 1)
9, Pigment Red 122), dyes such as merocyanine compounds, cyanine compounds, and squarylium compounds, and charge transfer agents used in organic electrophotographic photoreceptors (hydrazone compounds, pyrazirine compounds, triphenylmethane compounds, triphenylamine compounds, etc.), Conjugated conductive polymers such as polypyrrole, polyaniline, and polythiophene are used. These layers are formed by a method such as vapor deposition, spin coating and dipping. Vapor deposition is preferred for thinning and uniforming. The electron donating organic material layer (I) has an appropriate film thickness of 30 to 300 Å. If it exceeds 300 Å, J _SC does not increase, and if it is less than 30 Å, the light absorption efficiency of the layer itself decreases, and J _SC
Is reduced. A suitable film thickness of the electron donating organic compound layer (II) is 50 to 3000 Å.

As the back electrode used in the present invention, a metal having a high work function such as Au, Pt, Ni, Pd, Cu, Cr or Ag is used, and Au is particularly preferable because it is stable. The film thickness of this metal is preferably 50 to 3000 Å.

[0048]

The present invention will be described in more detail with reference to the following examples.

Example 1 Well-cleaned ITO glass (Matsuzaki Vacuum, 30Ω / □)
When the substrate temperature is about 250 ° C., argon is used as an introduction gas, and the zinc oxide is about 1 by RF magnetron sputtering.
It was provided with a thickness of 500Å. Then, a perylene tetracarboxylic acid dimethylimide pigment (exemplary structural formula No. A-1) was formed in a thickness of about 390Å by a vacuum deposition method, and then flavanthrone represented by the following structural formula (1) as an electron accepting substance. Was provided with a thickness of about 140Å, and then aluminum chlorophthalocyanine (AlClPc) was provided with a thickness of about 410Å, on which gold was vacuum-deposited. The area formed by ITO and gold was 0.25 cm ² . Lead wires were attached to the two electrodes with silver paste.

On the ITO side of this device, 75 mW / cm ²
The conversion efficiency was measured by applying a voltage swept at 6 mV / s while irradiating the white light of V _oc = 0.39.
V, J _SC = 1.40 mA / cm ² , ff = 0.40, and a conversion efficiency of 0.288% was obtained. This value is large for an organic photovoltaic element.

[0051]

[Chemical 1]

Example 2 The perylenetetracarboxylic acid dimethylimide pigment of Example 1 was applied at a thickness of about 390Å and then the electron-accepting substance (II).
Flavanthlon with a thickness of about 140Å, then A
A device was prepared in the same manner as in Example 1 except that the lClPc layer was set to 190Å and then 440Å of 2,7-dimethylquinacridone (QA-ME) was provided, and the conversion efficiency was measured. As a result, V _OC = 0.47 V, J _SC = 1.92 mA / cm
² , ff = 0.48, and a conversion efficiency of 0.581% was obtained. This value is large for an organic photovoltaic element.

Comparative Example 1 A device was prepared in the same manner as in Example 1 except that the perylenetetracarboxylic acid dimethylimide pigment layer of Example 1 was not provided, flavanthrone was formed to a thickness of about 310 Å, and then an AlClPc layer was provided to 390 Å. It was prepared and the conversion efficiency was measured. As a result, V _OC = 0.43 V, J _SC = 0.842 mA / cm
² , ff = 0.44, and the conversion efficiency was 0.213%, which was clearly lower than those in Examples 1 and 2.

The light amount of each wavelength was adjusted from the ITO side to the devices of Examples 1 and 2 and Comparative Example 1 so that the number of photons after passing through the electrode was 10 ¹⁴ , and monochromatic light was made incident. The quantum efficiency was calculated from the photocurrent at. This spectral sensitivity spectrum is shown in FIG. Examples 1 and 2 have almost no absorption of flavanthrone and AlClPc as compared with Comparative Example 54.
The quantum efficiency is remarkably increased around 0 to 580 nm, and the spectral sensitivity is flat. This is because the light absorbed by the perylene tetracarboxylic acid dimethylimide pigment layer was extracted as a photocurrent in some form.

Example 3 The perylene tetracarboxylic acid dimethylimide pigment of Example 1 was used in a thickness of about 460 Å, and then the perylene tetracarboxylic acid diphenyl imidazole pigment [the following structural formula (2)] was used as an electron accepting substance in an amount of about 150 Å. By thickness, then A
A device was prepared in the same manner as in Example 1 except that the lClPc layer was provided at 430Å, and the conversion efficiency was measured. As a result, V _OC =
0.47 V, J _SC = 1.80 mA / cm ² , ff = 0.
43, and a conversion efficiency of 0.480% was obtained. This value is large for an organic photovoltaic element. Comparative example 2
Compared with the two-layer structure of _J.sub.2 , the conversion efficiency was clearly higher, and in particular, the quantum efficiency of 500 to 600 nm was increased by the absorption of the perylenetetracarboxylic acid dimethylimide pigment.

[0056]

[Chemical 2]

(Mixture of trans isomer and cis isomer) Comparative Example 2 Without providing the perylenetetracarboxylic acid dimethylimide pigment layer of Example 3, the perylenetetracarboxylic acid diphenylimidazole pigment was applied at a thickness of about 350 Å and then AlC.
A device was prepared in the same manner as in Example 1 except that the 1Pc layer was provided at 380Å, and the conversion efficiency was measured. As a result, V _OC =
0.37 V, J _SC = 1.21 mA / cm ² , ff = 0.
The conversion efficiency was 33 and the conversion efficiency was 0.196%.

Example 4 The perylenetetracarboxylic acid dimethylimide pigment of Example 1 was used in a thickness of about 380Å, and then the anthraquinone acridone pigment (the following structural formula (3)) was used as an electron acceptor in a thickness of about 150Å. , Then AlClPc layer 140Å
A device was manufactured in the same manner as in Example 1 except that the device was provided with the thickness of QA-ME0440A, and the conversion efficiency was measured. As a result, V _OC = 0.36 V, J _SC = 1.21 m
A / cm ² , ff = 0.42 and conversion efficiency 0.240
%was gotten. This value is large for an organic photovoltaic element. Compared with the two-layer structure of Comparative Example 3, the J _SC and the conversion efficiency were obviously higher, and in particular, the quantum efficiency of 500 to 600 nm was increased due to the absorption of the perylenetetracarboxylic acid dimethylimide pigment.

[0059]

[Chemical 3]

Comparative Example 3 About 3 parts of the anthraquinone acridone pigment was prepared without providing the perylenetetracarboxylic acid dimethylimide pigment layer of Example 4.
A device was prepared in the same manner as in Example 1 except that an AlClPc layer was provided at a thickness of 70Å, then an AlClPc layer was provided at a thickness of 410Å, and QA-ME was not provided, and the conversion efficiency was measured. As a result, Vo
c = 0.24 V, Jsc = 0.730 mA / cm ² , f
f = 0.39 and the conversion efficiency was 0.090%.

Example 5 The perylene tetracarboxylic acid dimethylimide pigment of Example 1 was used in a thickness of about 340 Å, and then naphthalene tetracarboxylic acid diphenyl imidazole pigment [the following structural formula (4)] was used as an electron accepting substance in an amount of about 150 Å. A device was prepared in the same manner as in Example 1 except that an AlClPc layer having a thickness of 480 Å was provided next, and the conversion efficiency was measured. As a result, V _OC
= 0.48 V, J _SC = 1.25 mA / cm ² , ff =
The conversion efficiency was 0.39, and the conversion efficiency was 0.313%. This value is large for an organic photovoltaic element. Compared with the two-layer structure of Comparative Example 4, J _SC , the conversion efficiency is obviously higher,
In particular, the quantum efficiency of 500 to 600 nm was increased due to the absorption of the perylenetetracarboxylic acid dimethylimide pigment.

[0062]

[Chemical 4]

Comparative Example 4 The naphthalenetetracarboxylic acid diphenylimidazole pigment of Example 5 was formed without providing the perylenetetracarboxylic acid dimethylimide pigment layer of Example 5 and then Al
A device was prepared in the same manner as in Example 1 except that the ClPc layer was provided at 480Å, and the conversion efficiency was measured. As a result, V _OC =
0.43 V, J _SC = 0.849 mA / cm ² , ff =
The conversion efficiency was 0.32 and the conversion efficiency was 0.155%.

Example 6 The perylenetetracarboxylic acid dimethylimide pigment of Example 1 was used in a thickness of about 370Å, and then Bromanthanthrone (the following structural formula (5)) as an electron accepting substance was used in an amount of about 11
A device was prepared in the same manner as in Example 1 except that an AlClPc layer having a thickness of 0Å and then 440Å was provided, and the conversion efficiency was measured. As a result, V _OC = 0.44 V, J _SC = 1.55 m
A / cm ² , ff = 0.41 and conversion efficiency 0.368
%was gotten. This value is large for an organic photovoltaic element. Compared with the two-layer structure of Comparative Example 5, J _SC and conversion efficiency were obviously higher, and the spectral sensitivity at 500 to 600 nm was increased due to absorption of the perylenetetracarboxylic acid dimethylimide pigment.

[0065]

[Chemical 5]

Comparative Example 5 Bromanthanthrone of about 220 Å was prepared without providing the perylenetetracarboxylic acid dimethylimide pigment layer of Example 6.
A device was prepared in the same manner as in Example 1 except that an AlClPc layer of 430 Å was provided next, and the conversion efficiency was measured. As a result, V _OC = 0.26 V, J _SC = 0.850 m
A / cm ² , ff = 0.36 and conversion efficiency 0.109
%Met.

[0067]

The effects of the photovoltaic device of the present invention are summarized as follows.

Photovoltaic device including a portion composed of two continuous layers of an electron-accepting organic material layer and an electron-donating organic material layer from at least the incident light side between two electrodes having at least the light transmitting side on the incident light side. In the above, by providing a perylene tetracarboxylic acid dialkylimide pigment layer between the incident light side translucent electrode and the electron-accepting organic material layer, high conversion characteristics are realized as an organic photovoltaic element with a particularly wide spectral sensitivity range. can do.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a layer structure of a photovoltaic element of the present invention.

FIG. 2 is an explanatory diagram of another layer structure.

FIG. 3 is an explanatory diagram of still another layer configuration.

FIG. 4 is an explanatory diagram of still another layer configuration.

5 is a graph showing the relationship between quantum efficiency and wavelength in Examples 1 and 2 and Comparative Example 1. FIG.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Issei Nagai 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd.

Claims (1)

[Claims] 1. A photovoltaic device comprising a portion composed of two continuous layers of at least an electron-accepting organic compound layer and an electron-donating organic compound layer from at least the incident light side between two electrodes having at least a light transmitting property on the incident light side. In the power element, a photovoltaic element characterized in that a perylene tetracarboxylic acid dialkylimide pigment layer is provided between the incident light side transparent electrode and the electron-accepting organic material layer.