JPS62102569A - Organic solar battery - Google Patents

Abstract

PURPOSE:To inexpensively and simply form a battery by surface-modifying or coating a hydrocarbon plasma polymerization film with phthalocyanine material powder of a photoelectric conversion layer. CONSTITUTION:Styrene is used as monomer gas, and a coating layer of approx. 50Angstrom thick is formed by plasma polymerization with alpha-type copper phthalocyanine powder. Then, a charge transport agent and a binder resin are mixed with it, and liquefied. A gold layer 2 is coated in a thin film state with the solution. Then, the mixture of magnetic powder and phthalocyanine material powder 14 is contained at the topside on an electrode 13 in a vacuum tank. A surface-modified layer or a coating layer by the plasma polymerization is formed on the surface of the powder 14 by a glow discharge for the prescribed time. Thus, the photoelectric conversion layer is formed by coating. Since phthalocyanine material is coated with a polymerization film, an ageing change can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an organic solar cell using a phthalocyanine material.

(Prior Art) Organic pigments, such as phthalocyanine materials, have photovoltaic power and are being studied as materials for solar cells. FIG. 6 shows an example of a solar cell using nickel phthalocyanine. A vacuum-deposited film 32 of nickel phthalocyanine is formed on the gold electrode layer 3■, and an ultra-thin polyethylene film 3
3 (approximately 100 layers thick) to form an aluminum electrode layer 34. The conversion efficiency of this solar cell is about 1%.

(Problems to be Solved by the Invention) Phthalocyanine solar cells have conventionally been manufactured using a vacuum evaporation method, but in order to reduce costs, it is desirable to be able to manufacture them even more easily.

In addition, the electrical properties of phthalocyanine solar cells change significantly over time, especially in the early stages.

An object of the present invention is to provide a phthalocyanine solar cell that is easy to produce and inexpensive.

(Means for Solving the Problems) The organic solar cell according to the present invention includes a photoelectric conversion layer made of a mixture of phthalocyanine material powder, a charge transport agent, and a binder resin, and electrode layers laminated on both sides of the photoelectric conversion layer. and a translucent electrode layer, and is characterized in that the above phthalocyanine material powder is surface-modified or coated with carbide.

(Function) A phthalocyanine material powder having photoelectric conversion properties is mixed with a charge transport agent and a binder resin to form a photoelectric conversion layer. Therefore, the photoelectric conversion layer can be formed by coating. Furthermore, since the surface of the phthalocyanine material is modified or coated with a plasma-polymerized hydrocarbon film, deterioration over time can be prevented and environmental resistance (particularly adsorbed gas barrier properties) can be improved.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 schematically show cross sections of solar cells according to the present invention. In FIG. 1, a gold layer 2 is deposited on an aluminum substrate l. Next, a phthalocyanine material coated with a coating material to be described later (for example,
Applying a coating liquid in which powder 3a of α-type copper phthalocyanine shown in No. 166355 is dispersed in binder resin 3b,
The photoelectric conversion layer 3 is formed by firing. (The thickness of the surface modification or coating with the coating material is 20 to 200 mm.
number of people, preferably 20 to 80 people. In order to prevent carrier recombination, the film thickness is preferably 0.1 μm below the buttock.
The shoulder should be 1 to 0.5μ. ) A semi-transparent electrode layer 4 of aluminum is deposited thereon.

Then, a lead wire 5.5 is connected to both electrode layers 1.4. The photoelectric conversion layer 3 and the gold layer 2 form an ohmic junction, and the photoelectric conversion layer 3 and the semi-transparent layer 4 form a Schottky barrier. When light is irradiated from the semi-transparent layer 4 side, photovoltaic force can be extracted from the extraction line 5.5.

In the solar cell shown in FIG. 2, an ultra-thin transparent barrier layer 6 made of coating material ζ is formed between the photoelectric conversion layer 3 and the semi-transparent electrode layer 4 by plasma polymerization.

In the solar cell shown in FIG. 3, an ultra-thin transparent barrier 11f7 is formed between the gold layer 2 and the photoelectric conversion layer 3 by plasma polymerization. Note that in the solar cells shown in FIGS. 2 and 3, the direction of the current may be reversed. In addition, in FIGS. 2 and 3, the transparent barrier layer 6.7 is provided to allow light to efficiently reach the photoelectric conversion layer.
This is to change the Schottky barrier at the interface with the photoelectric conversion layer, improve carrier injection efficiency, and improve conversion efficiency as a result.

Next, the formation of the photoelectric conversion layer 3 in the solar cell shown in FIG. 1 will be further explained. As the phthalocyanine material, α-type copper phthalocyanine powder disclosed in the above-mentioned Japanese Patent Application Laid-open No. 166355/1988 is used. Approximately 50%
Forms a coating layer for storage. Next, 40 parts by weight of N-ethylcarbazole-3-aldehydemethylphenylhydrazone (MPH) as a charge transport agent and polyethylene resin as a binder resin were added to the thus prepared Kochite powder (20 parts by weight in terms of solid content). 40 parts by weight and dissolved in a solvent such as xylene at 60°C to form a coating liquid.

The coating solution obtained in this way is applied onto the gold layer 2 by a spraying method, a dipping method (when applying to a large area or irregularly shaped object), or a spinner two-speed switching method (when applying to a flat plate). Apply a thin film below. Here, sheet samples were prepared by wrapping and spraying a gold-deposited aluminum sheet around a drum. However, in the case of the spray method, for example, a thin aluminum film or Mylar sheet with Af2 vapor-deposited is wound around a drum, and the drum is A thin film can be obtained by spraying while rotating at high speed, or by chucking a plate-shaped substrate with a spinner and spraying from above while rotating at high speed. Next, the thin film was fired to form a photoelectric conversion layer 3.

In this way, large-area solar cells can be manufactured easily and inexpensively using coating means. When the thickness of the photoelectric conversion layer was measured, it was approximately 5,000 people. AQ was deposited as a semi-transparent film on this sample to serve as an upper electrode and a light introduction window. Here, A.M.
! When irradiated with light, a conversion efficiency of around 1% was obtained.

Next, coating by plasma polymerization method will be explained. In the plasma polymerization apparatus schematically shown in FIG. 4, a first electrode 12 connected to a high frequency power source 11 and a second electrode 13 made of a non-magnetic metal and grounded are provided in a vacuum chamber (not shown). The second electrode 13 has a dish shape, and accommodates a mixture of magnetic powder and phthalocyanine material powder 14 on the upper side. A rotatable magnet plate 15 immediately below the second electrode 13
is provided. During plasma polymerization, monomer gas is introduced, and while the magnet plate 15 is rotated, a high frequency electric field from the high frequency power source 11 is applied between the electrodes 12 and 13 to generate a glow discharge. The mixed powder moves as the magnet plate 15 rotates. By performing glow discharge for a predetermined period of time, a surface modification layer or a coating layer is uniformly formed on the surface of the phthalocyanine powder 14 by plasma polymerization.

In another plasma polymerization apparatus shown in FIG. 5, a first electrode 2 connected to a high frequency power source 21 is placed in a vacuum chamber (not shown).
2 and a second electrode 23 that is grounded. Both electrodes 22
．． A container 25 provided with a plurality of concave portions for accommodating phthalocyanine material powder is placed between the containers 23 and 23 .

This container 25 is placed on the tips of a plurality of rods. A part of the rod is fixed by a fixture, but the other part can be vibrated by a vibrator consisting of a permanent magnet 26 and an electromagnet 27. When the electromagnet 27 is driven by a frequency variable AC power source (not shown), the container 25 vibrates. When the frequency is changed to match the vibrations of the powder 24, the powder 24 causes convection (arrows indicate the direction of convection).
.

In this state, a plasma polymerized film is formed on the surface of the powder 24 by glow discharge of the monomer gas.

Electrical aging changes, especially initial efficiency changes, which are a problem in solar cells using phthalocyanine materials, can be solved by plasma polymerized films, especially carbide films using monomer gases [a] to [ii] (see Table 1). I was able to reduce it. The plasma polymerized coating material contains 8% tetrafluoroethylene.
Those coated by about 0 people had good results in terms of aging, moisture resistance, and repeated tests.

The phthalocyanine material used for the photoelectric conversion layer 3 is α-type hydrogen phthalocyanine, metal phthalocyanine, or a derivative thereof (crystal structure is α-type, β-type
type, γ type, σ type, ε type, τ type.

χ type or their intermediates, that is, amorphous) can be used. Specifically, the central metal atom of metal phthalocyanine is copper, silver, sodium, lithium, beryllium, magnesium, carunium, gallium, zinc, cadmium, barium, mercury, aluminum, indium, lanthanum, neodymium, samarium, europium, and gadolinium. , dysprosium, holmium, ytterbium, lutetium, titanium, tin, hafnium, lead,
These include thorium, vanadium, antimony, chromium, molybdenum, uranium, manganese, iron, cobalt, rhodium, palladium, osmium and platinum. Furthermore, the central nucleus of the phthalocyanine may be a metal halide having a valence of 3 or more, instead of a metal atom. Further, metal-free phthalocyanine derivatives such as copper-4-aminophthalocyanine, iron polyhalophthalocyanine, cobalt hexaphenylphthalocyanine, tetraazophthalocyanine, tetramethylphthalocyanine, and dialkylaminophthalocyanine can be used. These can be used alone or in combination.

A phthalocyanine derivative in which the hydrogen atom of the benzene nucleus in the phthalocyanine molecule is substituted with at least one electron-withdrawing group selected from the group consisting of a nitro group, a cyano group, a halogen atom, a sulfone group, and a carbosyl group, and a phthalocyanine and the phthalocyanine. A phthalocyanine-based photoconductive material composition obtained by mixing at least one unsubstituted phthalocyanine compound selected from the compounds with an inorganic acid capable of forming a salt with them and precipitating the mixture with water or a basic substance is used. You can also do that. In this case, the electron-withdrawing group-substituted phthalocyanine derivative is -
Any number of substituents in the molecule from 1 to 16 can be used, or the composition ratio of the electron-withdrawing group-substituted phthalocyanine derivative and other unsubstituted phthalocyanine compounds is such that the number of substituents in the former is the same. Unit phthalonanine in the composition 1
0.001 to 2 per molecule, preferably 0.002
It is preferable to set the number to 1. Inorganic acids that can form salts with the phthalocyanine compound used in producing the phthalocyanine-based photoconductive material composition include sulfuric acid, orthophosphoric acid, chlorosulfonic acid, hydrochloric acid, hydroiodic acid, hydrofluoric acid, Examples include hydrobromic acid.

The monomer gas for coating the surface of the powder of the phthalocyanine material described above by plasma polymerization includes [ico: methane type, ethylene type.

Acetylenic hydrocarbon, aromatic hydrocarbon, [B]: Halogen-containing hydrocarbon, [Box: Nitrogen-containing hydrocarbon, [2]: Oxygen-containing hydrocarbon, [E]: Boron-containing gas (B2
[A], [F] Niline-containing gas (P) mixed with H2, etc.)
H3) mixed [A], [To: silicon-containing gas (
[A], [S] mixed with germanium-containing gas (GeH, etc.): [A], [S] mixed with germanium-containing gas (GeH,): mixed with metal-containing gas (alcolades, organic metals, chelate rings, etc.) [A] or a mixture of at least two of the above monomer gases is used. The modified film thickness is 20 to 200, preferably 20 to 200.
There are 80 people. The effect of coating these is
It will look like Table 1. That is, in the coating film, the solvent resistance, heat resistance, gas permeability, and dispersibility of the phthalocyanine material are improved, and the electrical resistance is increased. It also has good light transmittance and prevents reflection. Furthermore, depending on the coating film, water repellency may be improved or the interfacial barrier may be reduced (without reducing efficiency with continuous use).

Electrical aging changes, especially initial efficiency changes, which are a problem in solar cells using phthalocyanine materials, can be solved by plasma polymerized films, especially carbide films using monomer gases [a] to [ii] (see Table 1). I was able to reduce it. In particular, ethylene hydrocarbons can also be used as antireflection films.

As charge transport agents, those shown in Table 2 were effective. In particular, MPH, DEH and 2-benzyloxy-4
-Diedylaminobenzaldehyde diphenylhydrazone was the best.

As the binder resin used for the blank photoelectric conversion layer 3 below, polyamide resin is the most efficient, but other examples include saturated polyester resin, polyamide resin, acrylic resin, ethylene-vinyl acetate polymer, and ionically crosslinked olefin copolymer. Thermoplastic binders such as polymers (ionomers), styrene-butadiene block copolymers, polycarbonates, vinyl chloride-vinyl acetate copolymers, cellulose esters, polyimides; epoxy resins, urethane resins, silicone resins, phenolic resins, melamine Resin, thermosetting binder such as xylene resin, alkyd resin, thermosetting acrylic resin; photocuring resin; photoconductive resin such as poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, etc. Hole.

In addition, instead of the phthalocyanine-based material, the photoelectric conversion powder may be a-Si: H, a-Ge: H, or a mixture of both powders, or one controlled by P and N types by doping with B and P. , respectively monomer gas [to] in Table 1
, [e] can also be used. Furthermore, it is fully predicted that it can be used as an electrophotographic photoreceptor in other fields.

(Effects of the Invention) A large-area solar cell can be easily produced at low cost using a coating method. Since it has a high dark resistance, it is easy to make it into an integrated module.

It can be applied to easily bendable Mylar sheets, aluminum sheets, etc., giving you more flexibility in how you use it.

Since the bandgap is considerably larger than that of Si single crystal,
It has good light absorption efficiency (particularly large absorption peaks in the long wavelength side of visible light and in the heat ray region).

Since it is a dispersion system of coachite powder, it is efficiently absorbed into the bulk by diffuse reflection of incident light.

Although the strong electric field region at the junction is utilized due to the Schottky barrier formed by metal-semiconductor contact, further efficiency can be achieved by providing a barrier with a metal-insulating ultra-thin film-semiconductor structure and utilizing tunneling charge injection.

Phthalocyanine materials have large electrical changes over time and initial efficiency changes, but this can be reduced by coating with a plasma polymerized film.

[Brief explanation of drawings]

1 to 3 are schematic cross-sectional views of solar cells, respectively. 4 and 5 are schematic cross-sectional views of the coating apparatus, respectively. FIG. 6 is a schematic cross-sectional view of a conventional solar cell. 2... Gold layer, 3... Photoelectric conversion layer,
3a...Kochite powder, 3b...Binder resin, 4...Semi-transparent layer. Patent applicant Minolta Camera Co., Ltd. Representative
People Patent Attorneys Aobai Ao and 2 others Figure 2 Figure 3 Figure 6

Claims (1)

[Claims] (1) It consists of a photoelectric conversion layer made by mixing phthalocyanine material powder, a charge transport agent, and a binder resin, and an electrode layer and a semitransparent electrode layer laminated on both sides of the photoelectric conversion layer, and the above phthalocyanine material powder is An organic solar cell characterized in that its surface is modified or coated with a hydrocarbon plasma polymerized film.