JP2002222970A - Photoelectric converter and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoelectric converter capable of being easily manufactured with a high quality at a low cost and a method for manufacturing the same and to provide a photoelectric converter capable of being formed in any shape with flexibility like a film or the like and having a light weight, excellent portability and a method for manufacturing the same. SOLUTION: The photoelectric converter comprises a photoelectric conversion layer 30 having a dispersing film for dispersing at least n-type semiconductor fine grains and organic p-type semiconductor fine grains, and a pair of electrodes 20 and 30 oppositely disposed through the layer 30. In this case, the pair of electrodes 20 and 30 have different work functions from each other. At least one of the electrodes 20 and 30 is translucent. The method for manufacturing the same is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion element that generates an electromotive force by light irradiation and a method for manufacturing the same.
The photoelectric conversion element of the present invention is used for, for example, a solar cell, an optical sensor, an optical operation element, and the like.

[0002]

2. Description of the Related Art In recent years, global warming due to the burning of fossil fuels and an increase in energy demand due to an increase in population have become major issues relating to the survival of humanity. Needless to say, sunlight has nurtured the environment of the earth since ancient times and has been an energy source for all living things, including humans. Therefore, recently, use of sunlight as an infinite and clean energy source that does not generate harmful substances has been studied. Above all, a photoelectric conversion element that converts light energy into electric energy, that is, a so-called solar cell, has attracted attention as a promising technical means.

As photovoltaic materials for solar cells, monocrystalline, polycrystalline, amorphous silicon, CuInSe,
An inorganic semiconductor made of a compound such as GaAs or CdS is used. Solar cells using these inorganic semiconductors exhibit relatively high energy conversion efficiencies of 10% to 20%, and are therefore widely used as power supplies for remote locations and as auxiliary power supplies for portable small electronic devices. However, in light of the purpose of suppressing the consumption of fossil fuels and preventing the deterioration of the global environment as described at the beginning, it is difficult to say that a solar cell using an inorganic semiconductor has been sufficiently effective at present. This is because solar cells using these inorganic semiconductors are manufactured by a plasma CVD method or a high-temperature crystal growth process, and require a lot of energy to manufacture devices. In addition, it contains components that may have a detrimental effect on the environment, such as Cd, As, and Se, and there is a concern about environmental destruction due to disposal of the element.

As a photovoltaic material that can improve this point,
Organic solar cells using organic semiconductors have been proposed. Organic semiconductors are excellent in that they have a variety, low toxicity, good processability and productivity, cost reduction by mass production is possible, and flexibility makes it easy to be flexible. It has features. As a result, organic solar cells have been actively studied for practical use.

[0005]

The above-mentioned organic solar cells are classified into two types, a Schottky type and a pn junction type, depending on the mechanism of dissociating the photo-generated charge pairs.
The Schottky type utilizes an internal electric field due to a Schottky barrier induced at a junction surface between an organic semiconductor and a metal. Such a Schottky type solar cell has a feature that a relatively large open-circuit voltage (Voc) can be obtained, but has a problem that the photoelectric conversion efficiency tends to decrease as the irradiation light amount increases. Furthermore, since a Schottky solar cell needs to form a thin film of an organic semiconductor by various vapor deposition methods,
It was not easy to manufacture.

On the other hand, a pn junction type utilizes an internal electric field generated at a junction surface between a p-type semiconductor and an n-type semiconductor. An organic / organic pn junction type using an organic material for both semiconductors is used. There is an organic / inorganic pn junction type using an inorganic substance. Here, organic / organic pn junction type and organic / organic pn junction type
Both of the inorganic pn junction type are generally called an organic pn junction type. Such an organic pn junction type solar cell is known to exhibit a relatively high conversion efficiency, but in many cases, like the Schottky type, needs to be formed by a vapor deposition method, which hinders improvement in productivity. Had become.

Further, organic pigments useful for solar cells have different photoelectric characteristics (electromotive characteristics) depending on the crystal form, and organic pigments are known to exhibit excellent photoelectric characteristics only in specific crystal forms. ing. However, since it is difficult to select a crystal form in a film forming process by a vapor deposition method, there is also a problem that it is difficult to obtain a semiconductor layer made of a pigment of a desired crystal form having high photoelectric characteristics.

Accordingly, the present invention has been made to solve the above-mentioned problems, and has as its object to provide a low-cost, high-quality photoelectric conversion element which can be easily manufactured, and a method of manufacturing the same. And Another object of the present invention is to provide a photoelectric conversion element which has flexibility like a film, can be formed into any shape, is lightweight and has excellent portability, and a method for manufacturing the same. I do.

[0009]

Means for Solving the Problems To achieve the above object, a photoelectric conversion element of the present invention comprises: a photoelectric conversion layer comprising at least a dispersion film in which n-type semiconductor fine particles and organic p-type semiconductor fine particles are dispersed; A photoelectric conversion element including a pair of electrodes opposed to each other with the photoelectric conversion layer interposed therebetween, wherein the pair of electrodes have different work functions from each other, and at least one of the electrodes has light transmittance. I do. According to such a photoelectric conversion element, the photoelectric conversion layer may be a dispersion film in which desired semiconductor fine particles are dispersed, and the method for forming the photoelectric conversion layer is not limited. Thereby, since the photoelectric conversion element of the present invention can manufacture the photoelectric conversion layer by a simple method such as a coating method, the manufacturing cost is reduced, and
It will be of high quality.

[0010] The photoelectric conversion element may further include a p-type semiconductor layer between the electrode having a larger work function than the other of the pair of electrodes and the photoelectric conversion layer. The p-type semiconductor layer is composed of a dispersion film in which the p-type semiconductor is dispersed or a thin film of the p-type semiconductor.

Further, the photoelectric conversion element further includes an n-type semiconductor layer between the electrode having a smaller work function than the other of the pair of electrodes and the photoelectric conversion layer. The n-type semiconductor layer is formed of a dispersion film in which an n-type semiconductor is dispersed or a thin film of an n-type semiconductor.

In addition, the photoelectric conversion layer further includes an electron transporting material and / or a hole transporting material.

In order to achieve the above object, a method of manufacturing a photoelectric conversion element according to the present invention comprises a step of applying and curing a dispersion obtained by dispersing n-type semiconductor fine particles and organic p-type semiconductor fine particles on at least the surface of a support having electrodes. And a counter electrode forming step of forming an electrode having a work function different from that of the electrode on the photoelectric conversion layer. According to such a method for manufacturing a photoelectric conversion element, a high-quality photoelectric conversion element can be easily manufactured by a low-cost coating method.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Here, FIG. 1 is an enlarged cross-sectional view for explaining a photoelectric conversion element as a first embodiment of the present invention. As shown in FIG. 1, the photoelectric conversion element includes a support 10, an electrode p20, a photoelectric conversion layer 30.
, An electrode n40, and a coating layer 50 are sequentially laminated. In this embodiment, the electrode p20 is used as an electrode having a large work function, and the electrode n40 is used as an electrode having a small work function. The photoelectric conversion element needs to reach the photoelectric conversion layer 30 from at least one of the arrows A and B shown in FIG. For example, in order for the irradiation light to reach the photoelectric conversion layer 30 from the arrow A, the support 10 and the electrode p20 are formed of a light transmissive material. Similarly, in order for the irradiation light to reach the photoelectric conversion layer 30 from the arrow B, the electrode n40 and the coating layer 50 are formed of a light transmissive material. Further, arrow A and arrow B
In order for the irradiation light to reach the photoelectric conversion layer 30 from both sides of the element 10, the elements 10, 20, 40 and 50 are formed of a light-transmitting material.

The material and thickness of the support 10 are not limited as long as the electrode p20 can be stably held on the surface. Therefore, the shape of the support 10 may be a plate shape or a film shape. For the support 10, for example, metals such as aluminum and stainless steel, alloys, plastics such as polycarbonate and polyester, wood, paper, cloth, and the like are used. When the irradiation light is incident from the arrow A side in FIG. 1, the support 10 must be made of a light-transmitting substance (material), and transparent glass, transparent plastic, or the like can be used. Here, transparency refers to a property of transmitting light in a predetermined wavelength region used in the photoelectric conversion element, for example, a visible light region at a high rate. The photoelectric conversion element of the present invention is desirably formed on the surface of the support 10, but when the electrode p20 itself has a certain degree of hardness and is self-supporting, the electrode p20 also serves as a support. In this case, the support 10 may be omitted.

As described above, the electrode p2 having a large work function
0, preferably work in order to enable forming a junction close to the organic p-type semiconductor fine particles P _p ohmic included in the photoelectric conversion layer 30 to be described later function is not less than 4.5 eV, is not less than 5.0eV Is more preferable. On the other hand, the electrode n40 having a small work function is composed of the n-type semiconductor fine particles P
_The work function is preferably 4.5 eV or less so that a junction close to ohmic with _n can be formed. Note that, in the present invention, the work functions of the pair of electrodes arranged to face each other may have a relative magnitude relationship with each other (that is, have different work functions). Therefore, also in the present embodiment, the work function of the electrode p20 is equal to that of the electrode n40.
It suffices if it is relatively large. In this case, both electrodes 2
The difference between the preferable work functions of 0 and 40 is preferably 0.5 eV or more.

As the electrode p20, metals such as gold and platinum, and zinc oxide, indium oxide and tin oxide (NES)
A), metal oxides such as tin-doped indium oxide (ITO) and fluorine-doped tin oxide (FTO) can be used. On the other hand, as the electrode n40, a metal such as aluminum, magnesium, indium, lead, and zinc, and an alloy such as silver-magnesium can be used. The electrode p20 and the electrode n40 may be formed by a vapor deposition method or a sputtering method, or may be formed by firing by a known sol-gel method or the like.

When the irradiation light is incident from the arrow A side in FIG. 1, the electrode p20 needs to be formed of a light-transmitting substance (material) together with the support 10. Similarly, when the irradiation light is incident from the arrow B side, the electrode n40 needs to be formed of a light-transmitting substance (material) together with a coating layer 50 described later. The electrode p20 is connected to the support 1 as described above.
A configuration that also serves as 0 may be used. At this time, an electrode having a certain degree of hardness and autonomy is used as the electrode p20.

[0019] The photoelectric conversion layer 30 is configured as a dispersion film obtained by dispersing at least the n-type semiconductor fine particles P _n and the organic p-type semiconductor fine particles P _P. In the photoelectric conversion layer within 30, pn between the n-type semiconductor fine particles P _n and the organic p-type semiconductor fine particles P _P
A junction is formed and charge separation occurs. At the electrode interface, the n-type semiconductor fine particles _Pn form a near ohmic junction with the electrode n40 having a smaller work function.
The organic p-type semiconductor fine particles P _p forms a junction close to the larger electrode p20 ohmic work function. Therefore, p
Electrons generated at the n-junction move between the n-type semiconductor fine particles P _n and are injected into the electrode n40, and holes generated at the pn junction move between the organic p-type semiconductor fine particles P _p to form the electrode p20.
, A potential difference is generated between the two electrodes 20 and 40. Therefore, it is expected that the photoelectric conversion element of the present invention shown in FIG. 1 can take out current outside.

The n-type semiconductor fine particles _Pn may use either an organic material or an inorganic material. The n-type semiconductor may be any one that exhibits stable n-type semiconductor properties even when fine particles are dispersed, and as an organic substance, a perylene pigment,
Perinone-based pigments, polycyclic quinone-based pigments, azo-based pigments, and the like, and inorganic substances such as zinc oxide, titanium oxide, and cadmium sulfide can be used.

The organic p-type semiconductor fine particles P _p need only be p-type semiconductors that exhibit stable p-type semiconductor characteristics even when dispersed in fine particles, and include phthalocyanine pigments, indigo or thioindigo pigments, and quinacridone pigments. No. As described above, when an organic pigment is used, the crystal form of the pigment is important, and it is necessary to make the crystal form exhibit high photoelectric characteristics. For example, in the case of chlorogallium phthalocyanine microparticles is an organic p-type semiconductor fine particles P _p, Cu
In the X-ray diffraction spectrum using Kα as a source, the Bragg angles (2θ ± 0.2 °) are 7.4 °, 16.6 °, 2
Crystal forms having strong diffraction peaks at 5.5 ° and 28.3 °, Bragg angles (2θ ± 0.2 °) of 6.8 °, 1
A crystal form having strong diffraction peaks at 7.3 °, 23.6 ° and 26.9 °, or a Bragg angle (2θ ± 0.2
°) is 8.7 to 9.2 °, 17.6 °, 24.0 °, 2
Crystal forms having strong diffraction peaks at 7.4 ° and 28.8 ° are preferred.

[0022] When using the hydroxygallium phthalocyanine as organic p-type semiconductor fine particles P _P, the X-ray diffraction spectrum as a radiation source a CuKa, Bragg angle (2θ ± 0.2 °) is 7.5 °, 9.9 ° , 12.5
°, 16.3 °, 18.6 °, 25.1 ° and 28.3
Crystal forms having a strong diffraction peak at ° are preferred.

[0023] When using the oxytitanium phthalocyanine as organic p-type semiconductor P _P, the X-ray diffraction spectrum as a radiation source a CuKa, Bragg angle (2 [Theta] ±
0.2 °) is 9.3 °, 10.6 °, 13.2 °, 1
5.1 °, 15.7 °, 16.1 °, 20.8 °, 2
Crystal forms with strong diffraction peaks at 3.3 ° and 26.3 °, 7.6 °, 10.2 °, 12.6 °, 13.2 °,
15.1 °, 16.3 °, 17.3 °, 18.3 °, 2
Crystal forms with strong diffraction peaks at 2.5 °, 24.2 °, 25.3 ° and 28.6 °, or 9.7 °, 11.
It is preferable to use crystal forms having strong diffraction peaks at 7 °, 15.0 °, 23.5 ° and 27.3 °.

As the dispersion medium (solvent) used for dispersing the semiconductor fine particles P _n and P _p , water, methanol, ethanol,
alcohols such as n-propanol, i-propanol, n-butanol, benzyl alcohol, acetone,
Ketones such as methyl ethyl ketone and cyclohexanone,
Amides such as dimethylformamide and dimethylacetamide, sulfoxides such as dimethylsulfoxide, cyclic or chain-like ethers such as tetrahydrofuran, dioxane, dimethylether, methylcellosolve and ethylcellosolve, methyl acetate, ethyl acetate, n-butyl acetate and the like Esters, methylene chloride, chloroform, carbon tetrachloride, aliphatic halogenated hydrocarbons such as dichloroethylene, trichloroethylene, etc., mineral oils such as ligroin, aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene, dichlorobenzene, etc. Aromatic halogenated hydrocarbons or the like can be used alone or in combination of two or more.

The n-type semiconductor fine particles P _n and the organic p-type semiconductor fine particles P _P The mass ratio of 100: 1 to 1: preferably in a 100 range of 100: 5 to 5: more be 100 preferable. Mass ratio of the n-type semiconductor fine particles P _n and the organic p-type semiconductor fine particles P _P of the photoelectric conversion layer 30 depends on the transmittance of the absorption coefficient of the semiconductor fine particles P _n and P _P the use illumination light. For example, in the case of using a phthalocyanine pigment having a strong absorption coefficient at a wavelength of 600~800nm organic p-type semiconductor fine particles P _P, 600 to during the irradiation light
Light having a wavelength of 800 nm is absorbed by the phthalocyanine-based pigment and is prevented from reaching the entire photoelectric conversion layer 30. Therefore, the use of phthalocyanine pigment, said wavelength as n-type semiconductor fine particles P _n (600 to 800 nm)
By using more zinc oxide or cadmium sulfide having high transmittance in the above, it is possible to reach the entire photoelectric conversion layer 30 without absorbing the irradiation light. As a result, the photoelectric conversion layer 30 can absorb the irradiation light in the entire layer, and may increase the conversion efficiency.

The thickness of the photoelectric conversion layer 30 is 0.05 to 5 μm.
And more preferably 0.05 to 3 μm. If the film thickness is too small, leakage between the electrodes may easily occur. On the other hand, if the film thickness is too large, the generated charges may not reach the electrodes.

A binder resin may be added to improve the film forming property of the photoelectric conversion layer 30. Examples of the binder resin include polyvinyl butyral resin, polyvinyl formal resin, polyvinyl acetal resins such as partially acetalized polyvinyl butyral resin in which a part of butyral is modified with formal or acetoacetal, and polyarylate resins (bisphenol A and phthalic acid). And polycondensates with polyether), polycarbonate resin, polyester resin, modified ether type polyester resin, phenoxy resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyvinyl acetate resin, polystyrene resin, acrylic resin, methacrylic resin, polyacrylamide resin , Polyamide resin, polyvinyl pyridine resin, cellulosic resin, polyurethane resin, epoxy resin, silicone resin, polyvinyl alcohol resin, polyvinyl pyrrolidone resin, casein and salt Vinyl - vinyl acetate copolymer, hydroxyl-modified vinyl chloride - vinyl acetate copolymer, carboxyl-modified vinyl chloride - vinyl acetate copolymer, vinyl chloride - vinyl acetate -
Vinyl chloride-vinyl acetate copolymers such as maleic anhydride copolymers, styrene-butadiene copolymers, vinylidene chloride-acrylonitrile copolymers, styrene-alkyd resins, silicone-alkyd resins, phenol-formaldehyde resins, etc. Can be used. Also,
The binder resin can also be selected from organic photoconductive polymers such as poly-N-vinyl carbazole, polyvinyl anthracene, polyvinyl pyrene, and polysilane.

The photoelectric conversion layer 30 has electrons as a charge transport agent.
Transport material and / or hole transport material can also be added
You. Thereby, the charge generated at the pn junction becomes more efficient
In some cases, it is possible to reach the electrode well. example
For example, the n-type semiconductor fine particles P of the photoelectric conversion layer_nAnd organic p-type semiconductor
Body particles P_pAnd the mass ratio to P_n: P_P= 10: 1
When biased, a charge transport agent that has less charge (here
In some cases, the addition of a hole transport material) may be effective.
That is, in the case of the above example, the n-type semiconductor fine particles P _nAppendage
The electrons generated due to the large addition amount are n-type semiconductor fine particles P_n
Organic p-type semiconductor particles
P_pHole transfer efficiency is low due to the low abundance ratio of
Would. Therefore, by adding a hole transport material,
Holes can be efficiently moved to the electrode.
It is considered to be.

As the electron transporting material, for example, 2, 4, 7
Electron accepting substances such as -trinitrofluorenone, 2,4,5,7-tetranitrofluorenone, and tetracyanoquinodimethane; and those obtained by polymerizing these electron accepting substances. As the hole transport material, 2,5-bis-
Oxadiazole derivatives such as (p-diethylaminophenyl) -1,3,4-oxadiazole, 1,3,5-
Triphenylpyrazoline, 1- [pyridyl- (2)]-
Pyrazoline derivatives such as 3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, aromatic tertiary monoamino compounds such as triphenylamine and benzylaniline, N, N′-diphenyl-N,
Aromatic tertiary diamino compounds such as N'-bis- (m-tolyl) benzidine, 3- (p-diethylaminophenyl) -5,6-di- (p-methoxyphenyl) -1,
1,2,4-triazine derivatives such as 2,4-triazine; hydrazone derivatives such as 4-diethylaminobenzaldehyde-2,2-diphenylhydrazone; hydrazone derivatives such as 2-phenyl-4-styrylquinazoline;
Quinazoline derivatives such as -phenyl-4-styrylquinazoline, benzofuran derivatives such as 6-hydroxy-2,3-di- (p-methoxyphenyl) benzofuran, p-
Examples thereof include α-stilbene derivatives such as (2,2-diphenylvinyl) -N, N-diphenylaniline, triphenylmethane derivatives, and polymers having a group consisting of these compounds in the main chain or side chain.

To the photoelectric conversion layer 30, various known surfactants and / or leveling agents can be further added to improve the dispersibility of the semiconductor fine particles and the film formability of the coating film. In addition, known antioxidants, UV absorbers, and the like can be added for the purpose of improving durability.

In the photoelectric conversion layer 30, the semiconductor fine particles P
the binder resin to be added in addition to _n and P _P, a charge-transporting substance, various additives, the addition amount of the combined or the like, the photoelectric conversion layer 3
It is preferably at most 25% by mass, more preferably at most 15% by mass. These substances may be added before or after the dispersion step.

In the photoelectric conversion device of the present invention, as shown in FIG. 1, it is preferable to form a coating layer 50 on the surface opposite to the support 10. This corresponds to electrode n20, electrode p
This is to prevent the oxidative deterioration and mechanical damage of the photoelectric conversion layer 40 and the photoelectric conversion layer 30. As the coating layer 50, for example, a curable resin is used. Examples of such a curable resin include known curable resins such as a curable epoxy resin, a curable acrylic resin, a curable silicone resin, and a curable phenol resin. Further, a curable substance such as an oligomer or an inorganic curing agent such as a silicon hard coat agent can be used instead of the curable resin. Further, the coating layer 50 can be formed by fusing glass, plastic, or the like with the heat-sealing sheet interposed therebetween. When the irradiation light is incident from the arrow B side in FIG.
It is also necessary to have light transmittance.

Hereinafter, with reference to FIG. 2 and FIG. 3, photoelectric conversion elements according to second and third embodiments of the present invention will be described in detail. Here, FIG. 2 is an enlarged cross-sectional view for explaining a photoelectric conversion element as a second embodiment of the present invention, and FIG. 3 is a view for explaining a photoelectric conversion element as a third embodiment of the present invention. It is an expanded sectional view of. Note that FIG.
In FIG. 3 and FIG. 3, the components of the photoelectric conversion element denoted by the same reference numerals as those in FIG. 1 indicate the elements having the same functions as those in FIG. 1, and the details are omitted.

The photoelectric conversion element of the second embodiment shown in FIG. 2 has a p-type semiconductor characteristic between the electrode p20 and the photoelectric conversion layer 30 in addition to the components of the first embodiment shown in FIG. The p-type semiconductor layer 60 is further provided. The photoelectric conversion element according to the third embodiment shown in FIG. 3 includes an electrode n40 and a photoelectric conversion layer 30 in addition to the components of the first embodiment shown in FIG.
Further has an n-type semiconductor layer 70 having n-type semiconductor characteristics. It is expected that the p-type semiconductor layer 60 and the n-type semiconductor layer 70 have an effect of increasing the injection efficiency of electrons or holes due to effects such as prevention of charge recombination at the electrode interface. Therefore, the p-type semiconductor layer 60 and the n-type semiconductor layer 70 may improve the photoelectric characteristics of the photoelectric conversion element in some cases.

The p-type semiconductor layer 60 shown in FIG. 2 can be formed by dispersing p-type semiconductor fine particles in a binder resin or by sintering or vapor-depositing them. it may be different even if the same as the organic p-type semiconductor fine particles P _p being dispersed in.
On the other hand, the n-type semiconductor layer 70 shown in FIG. 3 can be formed by dispersing n-type semiconductor fine particles in a binder resin or by sintering or vapor-depositing them. -Type semiconductor fine particles P _n dispersed in
May be the same or different. The layer thickness of the p-type semiconductor layer 60 and the n-type semiconductor layer 70 is
It is preferable to make it thinner.

As described above, in the photoelectric conversion element of the present invention, the photoelectric conversion layer 30 is formed as a dispersion film of the organic p-type semiconductor fine particles _Pp and the n-type semiconductor fine particles _Pn . Thereby, regardless of the properties (work function) of the electrodes, there is no influence on the movement of the charges, so that there is no difference in the generated electromotive force. Therefore, the positions of the electrode p20 and the electrode n40 may be opposite to those of the structure shown in FIG.

Hereinafter, a method for manufacturing the photoelectric conversion element of the present invention will be described by way of example with reference to FIG. First, the first
As a step, the electrode p20 is formed on the surface of the support 10 having a predetermined size (support forming step with electrodes). At this time,
The electrode p20 may be formed by a vacuum evaporation method, a sputtering method, an ion plating method, or the like, or may be formed by firing by a known sol-gel method or the like. The electrode p
If 20 itself has a certain degree of hardness and autonomy,
A structure in which the electrode p20 also serves as the support 10 may be used. At that time, the first step is omitted.

Next, as a second step, a thin film of the photoelectric conversion layer 30 is formed on the electrode p20 by a coating method (photoelectric conversion layer forming step). The more detailed second step will be described below. First, using the selected dispersion medium, the organic p-type semiconductor fine particles _Pp and the n-type semiconductor fine particles _Pn , and various substances such as a binder resin to be added as necessary are well dispersed or dissolved to prepare a dispersion liquid. I do. As the dispersion method, known methods such as ball mill dispersion, attritor dispersion, and sand mill dispersion can be used. It may be simultaneously dispersed semiconductor particles P _n and P _p in the dispersion step may be mixed after separately dispersed. Further, preferably to 0.5μm or less as a particle diameter of semiconductor particles P _n and P _p,
More preferably, the thickness is 0.01 μm or more and 0.1 μm or less. Therefore, after the dispersion step is completed, coarse particles may be removed using a membrane filter, a cotton filter, or the like having an appropriate size. Then, the prepared dispersion is applied onto the electrode n20 by various application methods such as spin coating, dipping, wire bar coating, and blade coating, and then cured by a thermosetting method, a light (ultraviolet) curing method, or the like. Thus, a thin film of the photoelectric conversion layer 30 is formed on the electrode n20.

Thereafter, as a third step, the photoelectric conversion layer 3
The electrode p40 is formed on the substrate 0 (a counter electrode forming step). Similarly to the electrode p20, the electrode n40 may be formed by firing by a vapor deposition method, a sputtering method, a known sol-gel method, or the like. Further, if necessary, the electrode p
The coating layer 50 is formed on the coating 40 (coating layer forming step). As a method for forming the coating layer 50, there is a method in which a coating solution or the like in which a curable resin is dissolved in an appropriate solvent is applied by a spin coating method or the like and then cured. As the curing method, any of a thermal curing method and a light (ultraviolet) curing method can be used. In addition, the coating layer 50 can be formed by a method in which a heat-fused resin sheet is pressed while being heated, a method in which a glass paste is applied and then heated, or the like.

Although the preferred embodiment of the present invention has been described above, the present invention can be variously modified and changed within the scope of the invention. The photoelectric conversion element of the present invention can be used for, for example, a solar cell, an optical sensor, an optical operation element, and the like.

[0041]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 In Example 1, the photoelectric conversion element shown in FIG. 4 was manufactured. Here, FIG.
FIG. 4A is a plan view of the photoelectric conversion element, and FIG. 4B is a cross-sectional view taken along line LL ′ in FIG. 4A. In addition, as shown in FIG. 4B, the photoelectric conversion element of Example 1 is a glass substrate (support).
110, a platinum electrode 120, a photoelectric conversion layer 130, a magnesium silver electrode 140, and a coating layer 150. Hereinafter, the manufacturing method will be described step by step.

<Step of forming support with electrodes> 15 mm × 15
In the center of the surface of the glass substrate 110 mm × 1.1 mm,
Platinum was formed to a thickness of 10 nm by sputtering and formed into a strip having a width of 5 mm using masking.
0 was set.

The Bragg angle in X-ray diffraction spectrum with a <photoelectric conversion layer forming step> The source of CuKα as an organic p-type semiconductor fine particles _{P p} (2θ ± 0.2 °) of 7.4
9 parts by mass of chlorogallium phthalocyanine having strong diffraction peaks at 0 °, 16.6 °, 25.5 ° and 28.3 °, 1 part by mass of polyvinyl butyral (Eslek BM-S, Sekisui Chemical) and n-butyl acetate 100 parts After mixing with glass parts and treating with glass beads for 1 hour using a paint shaker, coarse particles were removed with a 10 μm membrane filter to obtain _a chlorogallium phthalocyanine dispersion liquid La. Also, 9 parts by mass of dibromoanthanthrone as n-type semiconductor fine particles _Pn were mixed with 1 part by mass of polyvinyl butyral (ESLEC BM-S, Sekisui Chemical) and 100 parts by mass of n-butyl acetate, and the mixture was mixed with glass beads using a paint shaker. After processing for 1 hour and dispersing,
Remove coarse particles with a 10 μm membrane filter,
It was obtained dibromoanthoanthrone dispersion L _b. Chlorogallium phthalocyanine dispersion L _a and dibromo anthanthrone dispersion L _b and the weight ratio of _{L a: L b = 2:} 8 to become so mixed things as a coating solution, the glass substrate 1
Spin coating was performed on the surface on which the ten platinum electrodes 120 were formed. After wiping leaving only the central area of 7 mm × 7 mm, the layer was heated and dried at 120 ° C. for 60 minutes, and the photoelectric conversion layer 130 was dried.
Was formed. The thickness of the photoelectric conversion layer 130 was 150 nm.

<Step of Forming Counter Electrode> A magnesium silver electrode 140 having a width of 5 mm and a thickness of 20 nm was vapor-deposited thereon so as to be orthogonal to the platinum electrode 120.

<Coating Layer Forming Step> Further, a coating solution of 1 part by mass of bisphenol Z polycarbonate (Iupilon Z400, Mitsubishi Gas Chemical) dissolved in 9 parts by mass of chlorobenzene is spin-coated thereon, and a platinum electrode 120 and magnesium silver After wiping off a part of the electrode 140 so as to appear, it was heated and dried at 120 ° C. for 90 minutes to form a coating layer 150 having a thickness of 2 μm, whereby the photoelectric conversion element of Example 1 was manufactured.

Comparative Example 1 A photoelectric conversion element of Comparative Example 1 was produced in the same manner as in Example 1, except that the formation of the photoelectric conversion layer was changed to the following steps.

<Photoelectric Conversion Layer Forming Step> Glass Substrate 110
On the surface on which the platinum electrode 120 was formed, a vacuum deposited film having a thickness of 100 nm was formed using the same chlorogallium phthalocyanine as in Example 1 as a deposition source. In addition,
Film thickness 1 using dibromoanthanthrone as a deposition source
A vacuum deposited film having a thickness of 00 nm was formed, and a stacked photoelectric conversion layer was formed. At this time, the photoelectric conversion layer is 7 mm × 7 mm at the center.
Is wiped off, leaving only the area of With respect to the photoelectric conversion elements of Example 1 and Comparative Example 1, a fluorescent lamp (1
500 lux), open circuit voltage Voc, short circuit current I
sc, and the cell conversion efficiency η of the photoelectric conversion element (solar cell)
Was measured. Table 1 shows the results.

[0049]

[Table 1] As shown in Table 1, the photoelectric conversion element of Example 1 showed good results despite being manufactured by a coating method from a liquid in which organic semiconductor fine particles were dispersed. On the other hand, in Comparative Example 1 in which two thin films were stacked by the vapor deposition method, the conversion efficiency was low. This is considered to be because the crystal form of chlorogallium phthalocyanine formed by the vapor deposition method is different from the crystal form having high photoelectric characteristics in Example 1.

As described above, as the photoelectric conversion element of the present invention, an organic semiconductor fine particle having a high photoelectric characteristic as a crystal form can be used as it is, and therefore, excellent characteristics can be exhibited even by a coating method.

Example 2 In Example 1, a step of forming a p-type semiconductor layer (the following p-type semiconductor forming step) was added between the step of forming a support with electrodes and the step of forming a photoelectric conversion layer. Other than that, the photoelectric conversion element of Example 2 was produced like Example 1.

<P-type Semiconductor Layer Forming Step> In the X-ray diffraction spectrum using CuKα as a radiation source, the Bragg angle (2θ
9 parts by mass of chlorogallium phthalocyanine having strong diffraction peaks at 7.4 °, 16.6 °, 25.5 ° and 28.3 ° were added to polyvinyl butyral (Eslec BM-S, Sekisui Chemical). ) 1 part by mass and 100 parts by mass of n-butyl acetate were mixed and treated with glass beads for 1 hour using a paint shaker, and then coarse particles were removed with a 10 μm membrane filter to obtain a chlorogallium phthalocyanine dispersion. . This dispersion was spin-coated on the surface of the glass substrate 110 on which the platinum electrode 120 was formed, and dried by heating at 120 ° C. for 60 minutes to form a film having a thickness of 80 n.
m p-type semiconductor layers were formed.

[Example 3] In Example 1, a step of forming an n-type semiconductor layer (n-type semiconductor forming step described below) was added between the photoelectric conversion layer forming step and the counter electrode forming step. Then, a photoelectric conversion element of Example 2 was manufactured in the same manner as in Example 1.

<Step of Forming n-Type Semiconductor Layer> 9 parts by mass of dibromoanthanthrone is mixed with 1 part by mass of polyvinyl butyral (Eslec BM-S, Sekisui Chemical) and 100 parts by mass of n-butyl acetate, and a glass shaker and a paint shaker are mixed. , And dispersed for 1 hour, and coarse particles were removed with a 10 µm membrane filter to obtain a dibromoanthanthrone dispersion. The dispersion is applied to the photoelectric conversion layer 1
30 and spin-dried at 120 ° C. for 60 minutes to form an n-type semiconductor layer having a thickness of 80 nm.

Example 4 In Example 4, the photoelectric conversion element shown in FIG. 4 was manufactured. However, in Example 4, in addition to the components of the photoelectric conversion element of Example 1, the photoelectric conversion layer 1
30 has a p-type semiconductor layer and an n-type semiconductor layer on both surfaces. In Example 4, cadmium sulfide was used for the n-type semiconductor fine particles P _n and the n-type semiconductor layer.

<Step of forming support with electrodes> 15 mm × 15
In the center of the surface of the glass substrate 110 mm × 1.1 mm,
Platinum was formed to a thickness of 10 nm by sputtering and formed into a strip having a width of 5 mm using masking.
0 was set.

<Step of Forming Semiconductor Layer and Photoelectric Conversion Layer> Cu
In the X-ray diffraction spectrum using Kα as a source, the Bragg angles (2θ ± 0.2 °) are 7.4 °, 16.6 °, 2
9 parts by mass of chlorogallium phthalocyanine having strong diffraction peaks at 5.5 ° and 28.3 ° were mixed with 1 part by mass of polyvinyl butyral (Eslec BM-S, Sekisui Chemical) and 100 parts by mass of n-butyl acetate, and mixed with glass. was dispersed for 1 hour in a paint shaker with beads, coarse particles were removed with 10μm membrane filter to obtain a chlorogallium phthalocyanine dispersion L _c.
Further, 9 parts by mass of cadmium sulfide was mixed with 1 part by mass of polyvinyl butyral (Eslec BM-S, Sekisui Chemical) and 100 parts by mass of n-butyl acetate, and treated and dispersed with glass beads for 8 hours using a paint shaker. 1
The coarse particles were removed with a membrane filter having a 0 .mu.m, to obtain a cadmium sulfide dispersion L _d.

<< P-Type Semiconductor Layer Forming Step >> The obtained chlorogallium phthalocyanine dispersion _Lc is spin-coated on the surface of the glass substrate 110 on which the platinum electrode 120 is formed, and dried by heating at 120 ° C. for 60 minutes. A p-type semiconductor layer having a thickness of 80 nm was formed.

[0059] The weight ratio of "the photoelectric conversion layer forming step" and the resulting chlorogallium phthalocyanine dispersion L _c and cadmium sulfide dispersion L _d is L _c: a mixture such that the 8: L _d = 2 As a coating liquid, spin-coated on the p-type semiconductor layer, and dried by heating at 120 ° C. for 60 minutes.
A photoelectric conversion layer 130 having a thickness of 0 nm was formed.

<< Step of Forming N-Type Semiconductor Layer >> Further, the obtained cadmium sulfide dispersion liquid L _{d is} formed on the photoelectric conversion layer 130.
Was spin-coated and dried by heating at 120 ° C. for 60 minutes to form an n-type semiconductor layer having a thickness of 80 nm.

Here, the p-type semiconductor layer, the photoelectric conversion layer 1
After spin coating, each of the 30 and n-type semiconductor layers is formed by wiping except for a central 7 mm × 7 mm area of the glass substrate 110.

<Counter electrode forming step> On this, a magnesium silver electrode 140 having a width of 5 mm and a thickness of 20 nm was deposited so as to be orthogonal to the platinum electrode 120.

<Coating Layer Forming Step> Further, a coating solution obtained by dissolving 1 part by mass of bisphenol Z polycarbonate (Iupilon Z400, Mitsubishi Gas Chemical Co., Ltd.) in 9 parts by mass of chlorobenzene was spin-coated thereon. After wiping off a part of the electrode 140 so as to appear, it was heated and dried at 120 ° C. for 90 minutes to form a coating layer 150 having a thickness of 2 μm, whereby a photoelectric conversion element of Example 4 was manufactured.

Fifth Embodiment The photoelectric conversion of the fifth embodiment is performed in exactly the same manner as in the fourth embodiment except that a cadmium sulfide deposition film (50 nm in thickness) is formed as the n-type semiconductor layer. The device was manufactured.

Example 6 In Example 5, the obtained chlorogallium phthalocyanine dispersion, cadmium sulfide dispersion and a charge represented by the following structural formula were used as a coating solution for forming the photoelectric conversion layer 130. The photoelectric conversion of Example 6 was carried out in exactly the same manner as in Example 5, except that the mass ratio with the transport substance e was adjusted to be L _c : L _d : e = 8: 2: 0.4. An element was manufactured.

[0066]

Embedded image

[0067] In Example 7 Example 4 is instead of chlorogallium phthalocyanine as organic p-type semiconductor fine particles P _p and p-type semiconductor layer, a radiation source a CuKa X
Bragg angle (2θ ± 0.2) in X-ray diffraction spectrum
°) is 7.5 °, 9.9 °, 12.5 °, 16.3 °,
A photoelectric conversion element of Example 7 was produced in exactly the same manner as in Example 4, except that hydroxygallium phthalocyanine having strong diffraction peaks at 18.6 °, 25.1 ° and 28.3 ° was used.

[0068] In Example 8 Example 4, instead of chlorogallium phthalocyanine as organic p-type semiconductor fine particles P _p and p-type semiconductor layer, a radiation source a CuKa X
Bragg angle (2θ ± 0.2) in X-ray diffraction spectrum
°) is 9.7 °, 11.7 °, 15.0 °, 23.5 °
A photoelectric conversion element of Example 8 was produced in exactly the same manner as in Example 4, except that oxytitanium phthalocyanine having a strong diffraction peak at 27.3 ° was used.

Table 2 shows the results of performing the same evaluations as in Example 1 on the photoelectric conversion elements of Examples 2 to 8.

[0070]

[Table 2] As shown in Table 2, it can be seen that all of the photoelectric conversion elements of Examples 2 to 8 exhibited the same or better characteristics as those of Example 1.

[0071]

According to the present invention, the manufacturing cost using only the vapor deposition method can be obtained from a liquid in which n-type semiconductor fine particles and organic p-type semiconductor fine particles are dispersed by a simple method of coating. It is possible to provide a photoelectric conversion element exhibiting performance equal to or higher than that of an organic photoelectric conversion element having a higher value. Further, since it can be formed on a lightweight and flexible base material such as a PET film, a solar cell which is inexpensive and excellent in portability can be realized.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view illustrating a photoelectric conversion element according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view illustrating a photoelectric conversion element according to a second embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view illustrating a photoelectric conversion element according to a third embodiment of the present invention.

4A and 4B are schematic diagrams of the photoelectric conversion element of Example 1, FIG. 4A is a plan view of the photoelectric conversion element, and FIG. 4B is a cross-sectional view taken along line LL ′ in FIG. It is.

[Explanation of symbols]

 Reference Signs List 10 support 20 electrode p 30, 130 photoelectric conversion layer 40 electrode n 50, 150 coating layer 110 glass substrate (support) 120 platinum electrode 140 aluminum silver electrode

Claims (7)

[Claims] 1. A photoelectric conversion layer comprising at least a dispersion film in which n-type semiconductor fine particles and organic p-type semiconductor fine particles are dispersed, and a pair of electrodes opposed to each other via the photoelectric conversion layer. A photoelectric conversion element, wherein the pair of electrodes have different work functions from each other, and at least one of the electrodes has optical transparency. 2. The photoelectric conversion device according to claim 1, further comprising a p-type semiconductor layer between the electrode having a larger work function than the other of the pair of electrodes and the photoelectric conversion layer. element. 3. The photoelectric device according to claim 1, wherein the p-type semiconductor layer is composed of a dispersion film in which a p-type semiconductor is dispersed, or a thin film of the p-type semiconductor. Conversion element. 4. The semiconductor device according to claim 1, further comprising an n-type semiconductor layer between the electrode having a smaller work function than the other of the pair of electrodes and the photoelectric conversion layer. 3. The photoelectric conversion element according to item 1. 5. The photoelectric conversion element according to claim 4, wherein the n-type semiconductor layer is composed of a dispersion film in which the n-type semiconductor is dispersed or a thin film of the n-type semiconductor. 6. The photoelectric conversion device according to claim 1, wherein the photoelectric conversion layer further contains an electron transporting material and / or a hole transporting material. 7. A photoelectric conversion layer forming step of applying and curing a dispersion in which n-type semiconductor fine particles and organic p-type semiconductor fine particles are dispersed on at least the surface of a support having electrodes to form a photoelectric conversion layer; A method for manufacturing a photoelectric conversion element, comprising a counter electrode forming step of forming an electrode having a work function different from that of the electrode on a photoelectric conversion layer.