JP2014130932A - Manufacturing method of organic thin film solar cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an organic thin film solar cell which improves coating properties of an organic layer and prevents defects of the solar cell in the manufacturing of the organic thin film solar cell.SOLUTION: A manufacturing method of an organic thin film solar cell having at least a pair of electrodes and an organic layer 37 on a substrate includes a processing step where remote type atmospheric pressure plasma treatment is performed on the organic layer 37.

Description

  The present invention relates to a method for producing an organic thin film solar cell.

Studies on organic thin-film solar cells using organic semiconductor layers are being conducted.
In the production of organic thin-film solar cells, it has been proposed to reduce the production cost by forming each layer by a wet process by coating (Patent Document 1).

  On the other hand, the organic semiconductor layer included in the organic thin film solar cell has a property of being easily deteriorated in the atmosphere. Deterioration due to humidity is particularly likely to occur. Therefore, when the organic semiconductor layer is formed in the atmosphere, the organic semiconductor layer may be deteriorated in the organic semiconductor layer forming process. In contrast, Non-Patent Document 1 describes that when an organic thin film solar cell is manufactured, it is necessary to form a film in an inert gas atmosphere such as nitrogen.

JP 2011-35258 A

The Forefront of Effective Use of Solar Energy (issued by NTS Corporation, 2008) Chapter 4-Organic Thin Film Solar Cell Manufacturing Equipment

In the manufacture of an organic thin film solar cell, the present inventors have examined the formation of another layer on the organic layer by a wet process, and it has been extremely difficult to form the film on the organic layer. Therefore, when an attempt was made to improve the coatability by surface treatment, a new problem was found that defects were generated in the solar cell when a known method such as corona treatment or UV treatment was applied to the organic layer.
The present invention solves such problems, and in manufacturing an organic thin film solar cell, improves the coating property of the organic layer and does not cause defects in the solar cell, and a method for manufacturing the organic thin film solar cell Is to provide.

The present inventors have studied to solve the above problems, and have found that defects generated in the solar cell are caused by damage to the organic layer due to the surface treatment. The surface treatment with less damage to the organic layer is repeatedly studied, and the remote atmospheric pressure plasma treatment is applied to the organic layer, so that the organic layer is not damaged and the surface modification is sufficient. The present invention has been completed.
The present invention is a method for producing an organic thin film solar cell having at least a pair of electrodes and an organic layer on a substrate,
And a processing step of performing a remote atmospheric pressure plasma treatment on the organic layer.

  Further, it is preferable that the processing gas used for the remote atmospheric pressure plasma processing in the processing step has an oxygen concentration of 3000 ppm or less.

Moreover, it is preferable that the said process process is performed within a dry room, and it is preferable that the said dry room is an atmosphere with a dew point of -10 degrees C or less.
Moreover, it is preferable that it is a roll-to-roll type manufacturing method.

  According to the present invention, it is possible to provide a method for producing an organic thin-film solar cell, which performs appropriate surface modification on the organic layer surface and does not damage the organic layer.

It is a schematic diagram which shows an example of the remote type atmospheric pressure plasma processing apparatus used by this embodiment. It is a schematic diagram showing the layer structure of an organic thin film solar cell element. It is a schematic diagram showing the layer structure of an organic thin film solar cell. It is a schematic diagram showing the layer structure of an organic thin film solar cell.

Hereinafter, the present invention will be described in detail while showing specific embodiments, but it is needless to say that the present invention is not limited to the illustrated specific embodiments.
A method of manufacturing an organic thin film solar cell according to an embodiment of the present invention includes a processing step of performing a remote atmospheric pressure plasma treatment on an organic layer of an organic thin film solar cell having at least a pair of electrodes and an organic layer on a substrate. Including.

<1. Configuration of organic thin film solar cell>
The organic thin film solar cell according to this embodiment has at least a pair of electrodes and an organic layer on a substrate. The organic thin film solar cell includes an organic thin film solar cell element, and the organic thin film solar cell element generally has a configuration in which a lower electrode, an organic layer (including a buffer layer and an active layer), and an upper electrode are sequentially stacked on a substrate. The detail of the layer which comprises these organic thin film solar cell elements is mentioned later.
In this embodiment, the organic layer such as the buffer layer and the active layer is subjected to a remote atmospheric pressure plasma treatment, which will be described later, on the organic layer, as a problem that the coating is difficult when the film is formed by coating. It is solved by this.

<2. Plasma treatment process>
The plasma processing step according to this embodiment is characterized by performing a remote atmospheric pressure plasma processing on the organic layer.
In response to the above-described problem that it is difficult to form a film by coating on the organic layer, the present inventors tried surface treatment on the organic layer. However, when a known surface treatment such as corona treatment or UV treatment is applied, a new problem has been found that defects occur in solar cells.
The present inventors further examined the defects of the solar cell due to the application of the surface treatment. As a result of the surface treatment, the energy of the strength at which active species can be generated extends into the organic layer, and the polymer in the organic layer acts. It was considered that defects such as a bond breakage and a decrease in photoelectric conversion efficiency may occur.
As a result of examining the surface treatment method based on the above consideration, the surface of the type in which the object to be treated is directly arranged between the electrodes as in the corona treatment or the type in which the UV lamp and the object to be treated are opposed as in the UV treatment. Rather than a treatment, a processing method with low energy applied to the object to be treated, that is, a remote type atmospheric pressure plasma treatment, which is a surface treatment in which the object to be treated is disposed outside the electrode and the plasma generated from the electrode is sprayed. It has been found that the above-mentioned problems can be solved by adopting it.

<2-1. Remote atmospheric pressure plasma treatment>
Remote atmospheric pressure plasma treatment is a type of surface treatment in which an object to be treated is placed outside the electrode and plasma generated from the electrode is sprayed, and the object to be treated is placed directly between the electrodes for plasma treatment. This is different from the surface treatment. Therefore, the present invention can be applied even if the object to be processed is not a flat surface, and is particularly suitable for surface treatment of an object to be processed having a curved surface structure or a three-dimensional structure.
As an apparatus for performing remote atmospheric pressure plasma processing, for example, an apparatus disclosed in Japanese Patent Laid-Open No. 11-260597 and an apparatus disclosed in Japanese Patent Laid-Open No. 2004-207145 are exemplified. Is briefly explained.

FIG. 1 is a schematic diagram showing an example of a remote atmospheric pressure plasma processing apparatus used in this embodiment.
The remote atmospheric pressure plasma processing apparatus 40 includes a pair of electrodes 35 and a reaction tube 32 in a frame 30. The frame 30 is preferably formed of an insulating material from the viewpoint of stabilization of plasma discharge, and specifically, glassy materials such as quartz, alumina, and yttria partially stabilized zirconium, ceramic materials, and the like are mentioned. It is done. Examples of the material of the electrode 35 include metals such as iron, copper, and aluminum.
In order to stabilize the plasma discharge, the electrode 35 is preferably not in direct contact with the gas material for discharge treatment, and the electrode surface is preferably coated with a coating of an insulating material. Examples of the insulating material used for the coating include glassy materials such as quartz, alumina, and yttria partially stabilized zirconium, and ceramic materials. Furthermore, a dielectric material such as titania, SiO ₂ , AlN, Si ₃ N, SiC, diamond-like carbon film, barium titanate, lead zirconate titanate, or the like can be used. However, when a dielectric material is used, the dielectric constant is preferably 2000 or less.
In coating the surface of the electrode 35, a frame 30 is formed of an insulating material, and the electrode 35 is inserted and adhered inside the frame 30, and powder such as alumina, barium titanate, lead zirconate titanate or the like is used. Plasma spraying method in which it is dispersed in plasma and sprayed on the surface of the electrode 35, inorganic powder such as silica, tin oxide, titania, zirconia and alumina is dispersed with a solvent and sprayed on the surface of the electrode 35 with a spray or the like. A so-called soot coating method in which, after coating, melting at a temperature of 600 ° C. or higher, a method for forming a glassy film by a sol-gel method. Etc. can be adopted. Furthermore, the surface of the electrode 35 can be coated with an insulating material by vapor deposition (CVD) or physical vapor deposition (PVD). By adopting these methods, the insulation is extremely dense and smooth with poor adsorptivity. The surface of the electrode 35 can be coated with a coating of a conductive material, and the stabilization of discharge can be further promoted.
The distance between the pair of electrodes is appropriately determined in consideration of the magnitude of the applied voltage, etc., but is usually 0.1 mm or more, preferably 0.5 mm or more, usually 5 mm or less, preferably 3 mm or less. is there.

  An electric field such as a high frequency, a pulse wave, or a microwave is applied to the pair of electrodes to generate plasma. It is preferable to apply a pulse electric field, and in particular, a pulse electric field having a rise time and / or a fall time of 10 μs or less is preferable. More preferably, it is 50 ns to 5 μs. The rise time here refers to the time during which the voltage (absolute value) increases continuously, and the fall time refers to the time during which the voltage (absolute value) decreases continuously.

The electric field strength of the pulse electric field is usually 1 kV / cm or more, preferably 20 kV / cm or more, and usually 1000 kV / cm or less, preferably 300 kV / cm or less. The frequency of the pulse electric field is preferably 0.5 kHz or more. By setting the frequency to 0.5 kHz or more, the processing time can be shortened. The upper limit is not particularly limited, but it may be a high frequency band such as 13.56 MHz that is commonly used and 500 MHz that is used experimentally. In consideration of ease of matching with the load and handling, 500 kHz or less is preferable. By applying such a pulse electric field, the processing speed can be controlled.
The power applied to the electrode is usually 40 W / cm or less for stable discharge, and 30 W
/ Cm or less is preferable.

The reaction tube 32 is supplied with a discharge treatment gas from a gas inlet 31. The introduced gas generates plasma by applying an electric field. The generated plasma 33 is ejected from the plasma ejection port 34 toward the organic layer 37 that is the object to be treated, and the surface treatment of the organic layer 37 is performed.
In the present embodiment, the surface treatment is performed so that the coating film can be formed on the organic layer, and the hydrophilicity (wetting property) of the surface of the organic layer 37 may be improved. Specifically, the surface treatment is preferably performed so that the contact angle of pure water on the surface of the organic layer 37 is 65 degrees or less, preferably 55 degrees or less, more preferably 45 degrees or less. In addition, the contact angle in this invention is a contact angle measured based on JIS2396.

Examples of the gas material for discharge treatment that enables such surface treatment include oxygen-containing compounds such as air, nitrogen element-containing compounds such as nitrogen and ammonia, and the like. Specifically, nitrogen or a gas containing a small amount of oxygen or clean dry air (CDA) based on nitrogen is preferably used. A small amount of rare gas may be added for the purpose of facilitating discharge.
In this embodiment, since the organic layer which is a to-be-processed object is easily damaged by active species such as plasma, it is preferable to reduce the concentration of the processing gas material used as the active species source in the processing gas. For example, when the processing gas raw material is O ₂ , the O ₂ concentration in the processing gas is preferably 3000 ppm or less.

A gas for discharge treatment is introduced from the gas inlet 31 and an electric field is applied to generate plasma 33, which is ejected from the plasma outlet 34 toward the organic layer 37.
The distance 36 between the plasma jet 34 and the organic layer 37 is usually 2 mm or more, preferably 3 mm or more from the viewpoint of not damaging the organic layer 37 excessively. The upper limit only needs to allow surface treatment, and is usually 50 mm or less, and preferably 20 mm or less.

<2-2. Processing atmosphere>
This embodiment is a method for manufacturing an organic thin film solar cell, and it is preferable that the organic thin film solar cell be performed in an atmosphere with as low humidity as possible in the manufacturing process because there is concern about deterioration due to water. For this reason, the plasma treatment process according to this embodiment is preferably performed in a dry room.

  The dry room only needs to have a dry environment. For example, the dry room itself may be provided with an air conditioning adjusting means for reducing moisture in the room, or a moisture adsorbing means and a moisture removing means may be brought into the room. Examples of the air conditioning adjustment means include an apparatus that can remove moisture from the room by connecting an air conditioner, a compressor, and the like to the duct. Examples of the moisture adsorbing means and the moisture removing means include moisture adsorbing substances such as silica gel, alumina and activated carbon.

  The dry room does not need to be completely sealed as long as the atmosphere can be a dry environment. Therefore, it is possible to easily carry out the organic thin film solar cell after manufacture, carry in the material, and the like.

This embodiment is preferably applied when manufacturing an organic thin film solar cell industrially. Therefore, it is preferable that the dry room has a size capable of mass-producing organic thin-film solar cells. Moreover, it is preferable that the size is compatible with a roll-to-roll type manufacturing apparatus, and it is preferable that a space for storing a roll of an intermediate product or a roll of a finished product is secured. Moreover, it is preferable that it is a magnitude | size which can respond even when manufacturing the organic thin-film solar cell whose length of a roll exceeds 100 m.
From such a viewpoint, in the case of a substantially rectangular parallelepiped, the size of the dry room is preferably 3 m or more, more preferably 5 m or more, and preferably the room area has a size of 500 m ² or more, more preferably 750 m ² or more.

The atmosphere of the dry room may be any environment that has a lower moisture environment than the atmosphere, but usually has a dew point of −10 ° C. or lower, preferably a dew point of −20 ° C. or lower, more preferably a dew point of −30 ° C. or lower, and particularly preferable. Is an atmosphere of −38 ° C. or lower, more preferably −40 ° C. or lower. By setting it as such an atmosphere, deterioration of the organic layer of an organic thin-film solar cell can be prevented. The atmosphere in the dry room is adjusted by measuring with a moisture sensor or the like and removing water as necessary.
The cleanliness in the dry room is preferably class 1000 or less. If the degree of cleanness is poor, environmental foreign substances adhere to the film formation surface, and defects are likely to occur on the film formation surface. Specifically, when the environmental foreign substance is a conductive substance, a short circuit or the like occurs, and when it is not a conductive substance, insulation or the like occurs. The cleanliness is determined based on JIS B9920.

  As described above, since the organic thin film solar cell is liable to be deteriorated by water, the plasma treatment process according to this embodiment is preferably performed in a dry room. However, when the present inventors examined the plasma treatment in the dry room, it was found that the damage to the organic layer due to the surface treatment in the dry room was larger than that under normal humidity such as 40% Rh. did. This is because, under normal humidity, some of the generated active species such as plasma react with the moisture in the atmosphere and disappear, but in the dry room, the moisture in the atmosphere is extremely small, and the active species The present inventors consider that damage to the organic layer is high because it hardly disappears.

  For this reason, the present inventors have found that it is preferable that the remote atmospheric pressure plasma treatment be performed under milder conditions in the dry room. Thus, by performing the remote atmospheric pressure plasma treatment in a dry room under milder conditions, damage to the solar cell can be minimized in the manufacture of the organic thin film solar cell.

In the treatment process according to this embodiment, it is preferable to further reduce the concentration of the active species in the process gas material in the dry room. For example, when the active species raw material is O ₂ , the O ₂ concentration in the processing gas is preferably 500 ppm or less, more preferably 300 ppm or less, further preferably 250 ppm or less, and 200 ppm or less. It is particularly preferred.
Further, it is preferable to increase the distance between the plasma injection port and the organic layer. The distance between the plasma injection port and the organic layer is preferably 3 mm or more, more preferably 5 mm or more. In addition, it is preferable to reduce the discharge power as long as stable discharge is possible. In order to reduce the discharge power, means such as lowering the voltage, lowering the frequency of the pulse electric field, and shortening the rise and fall times of the pulse electric field can be cited. In addition, it is also preferable to intentionally mix a small amount of molecules that shorten the active species lifetime. An example of a molecule that shortens the active species lifetime is water.
When performing a treatment process in a dry room, it is preferable to employ at least one of the above-described means, and it is more preferable to employ a plurality of types.

<3. Organic thin film solar cell element>
An organic thin film solar cell is manufactured by sealing an organic thin film solar cell element.
The organic thin-film solar cell element usually has at least a pair of electrodes, an organic active layer existing between the electrodes, and an electron extraction layer existing between the organic active layer and one of the electrodes. FIG. 2 shows a general layer structure of the organic thin film solar cell element. An organic thin film solar cell element 107 shown in FIG. 2 includes a solar cell element substrate 106, a lower electrode 101 as a cathode, an electron extraction layer 102, an active layer 103 (a layer containing a p-type semiconductor compound and an n-type semiconductor material), It has a layer structure in which a hole extraction layer 104 and an upper electrode 105 as an anode are sequentially formed. In FIG. 1, the lower electrode 101 exists above the upper electrode 105. In this specification, the upper electrode and the lower electrode refer to the upper electrode and the lower electrode when the solar cell element substrate 106 is the bottom. The electrode laminated on the solar cell element substrate is referred to as a lower electrode. Further, among the electron extraction layer 102, the active layer 103, and the hole extraction layer 104, a layer containing an organic component may be collectively referred to as an organic layer, and the electron extraction layer 102 and the hole extraction layer 104 are collectively referred to as a buffer layer. May be called.

<3-1. Solar cell element substrate>
The organic thin film solar cell element has a solar cell element substrate (hereinafter also simply referred to as an element substrate) serving as a support. That is, an electrode and an active layer are formed on the element substrate.
The material for the element substrate is not particularly limited as long as the effects of the present invention are not significantly impaired. Suitable examples of the element substrate material include inorganic materials such as quartz, glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, Fluoropolymer film, polyolefin such as vinyl chloride or polyethylene; organic material such as cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate, polynorbornene or epoxy resin; paper material such as paper or synthetic paper; stainless steel Examples thereof include composite materials such as those obtained by coating or laminating a surface of a metal such as titanium or aluminum to impart insulation.
In particular, when manufacturing solar cell elements in a roll-to-roll format, materials other than inorganic materials such as quartz, glass, sapphire or titania (organic materials, paper materials, composite materials, etc.) can be mentioned, especially resin materials Is preferred.

  There is no restriction | limiting in the shape of an element substrate, For example, things, such as plate shape, a film form, or a sheet form, can be used. Moreover, although there is no restriction | limiting in the film thickness of an element board | substrate, it is 5 micrometers or more normally, Preferably it is 20 micrometers or more, on the other hand, it is 200 micrometers or less normally, Preferably it is 100 micrometers or less. It is preferable that the thickness of the substrate is 5 μm or more because the possibility that the strength of the organic thin-film solar cell element is insufficient is reduced. It is preferable that the thickness of the element substrate is 200 μm or less because the cost is suppressed and the weight does not increase.

<3-2. Electrode>
The electrode has a function of collecting holes and electrons generated by light absorption. Therefore, the pair of electrodes includes an electrode suitable for collecting holes (hereinafter also referred to as an anode) and an electrode suitable for collecting electrons (hereinafter also referred to as a cathode). Is preferably used. Any one of the pair of electrodes may be translucent, and both may be translucent. Translucency means that sunlight passes through 40% or more. Moreover, it is preferable that the sunlight transmittance of the transparent electrode is 70% or more in order to allow light to reach the active layer 103 through the transparent electrode. The light transmittance can be measured with a normal spectrophotometer.

  The anode is an electrode generally made of a conductive material having a work function higher than that of the cathode and having a function of smoothly extracting holes generated in the active layer.

Examples of anode materials include conductive metal oxides such as nickel oxide, tin oxide, indium oxide, indium tin oxide (ITO), indium-zirconium oxide (IZO), titanium oxide, indium oxide, and zinc oxide; Examples thereof include metals such as gold, platinum, silver, chromium and cobalt, or alloys thereof. These materials are preferable because they have a high work function, and further, PE in which a polythiophene derivative is doped with polystyrene sulfonic acid.
Since a conductive polymer material represented by DOT: PSS can be laminated, it is preferable. When laminating such a conductive polymer, the work function of this conductive polymer material is high, so even if it is not a material with a high work function as described above, it is suitable for cathodes such as Al and Mg. Metals can also be widely used. PEDOT: PSS in which a polythiophene derivative is doped with polystyrene sulfonic acid, or a conductive polymer material in which polypyrrole, polyaniline, or the like is doped with iodine or the like can also be used as an anode material. When the anode is a transparent electrode, it is preferable to use a light-transmitting conductive metal oxide such as ITO, zinc oxide or tin oxide, and ITO is particularly preferable.

  The film thickness of the anode is not particularly limited, but is usually 10 nm or more, preferably 20 nm or more, and more preferably 50 nm or more. On the other hand, it is usually 10 μm or less, preferably 1 μm or less, more preferably 500 nm or less. When the thickness of the anode is 10 nm or more, the sheet resistance is suppressed, and when the thickness of the anode is 10 μm or less, light can be efficiently converted into electricity without decreasing the light transmittance. When the anode is a transparent electrode, it is necessary to select a film thickness that can achieve both light transmittance and sheet resistance.

  The sheet resistance of the anode is not particularly limited, but is usually 1Ω / □ or more, on the other hand, 1000Ω / □ or less, preferably 500Ω / □ or less, more preferably 100Ω / □ or less.

  Examples of the anode forming method include a vacuum film forming method such as a vapor deposition method or a sputtering method, or a wet coating method in which an ink containing nanoparticles or a precursor is applied to form a film.

  The cathode is generally an electrode made of a conductive material having a low work function and having a function of smoothly extracting electrons generated in the active layer. The cathode is adjacent to the electron extraction layer.

  Examples of cathode materials include platinum, gold, silver, copper, iron, tin, zinc, aluminum, indium, chromium, lithium, sodium, potassium, cesium, calcium, and magnesium, and alloys thereof; lithium fluoride And inorganic salts such as cesium fluoride and metal oxides such as nickel oxide, aluminum oxide, lithium oxide, and cesium oxide. These materials are preferable because they are materials having a low work function. Similarly to the anode, a material having a high work function can be used for the cathode by using an n-type semiconductor such as titania having conductivity as the electron extraction layer. From the viewpoint of electrode protection, the cathode material is preferably a metal such as platinum, gold, silver, copper, iron, tin, aluminum, calcium or indium, or an alloy using these metals such as indium tin oxide.

  The film thickness of the cathode is not particularly limited, but is usually 10 nm or more, preferably 20 nm or more, more preferably 50 nm or more. On the other hand, it is usually 10 μm or less, preferably 1 μm or less, more preferably 500 nm or less. When the film thickness of the cathode is 10 nm or more, the sheet resistance is suppressed, and when the film thickness of the cathode is 10 μm or less, light can be efficiently converted into electricity without decreasing the light transmittance. When the cathode is a transparent electrode, it is necessary to select a film thickness that achieves both light transmittance and sheet resistance.

  The sheet resistance of the cathode is not particularly limited, but is usually 1000Ω / □ or less, preferably 500Ω / □ or less, and more preferably 100Ω / □ or less. Although there is no restriction on the lower limit, it is usually 1Ω / □ or more.

  As a method for forming the cathode, there are a vacuum film formation method such as a vapor deposition method or a sputtering method, or a wet coating method in which an ink containing nanoparticles or a precursor is applied to form a film.

  Furthermore, the anode and the cathode may have a laminated structure of two or more layers. In addition, characteristics (electric characteristics, wetting characteristics, etc.) may be improved by performing surface treatment on the anode and the cathode.

  After laminating the anode and cathode, the photoelectric conversion element is usually heated in a temperature range of 50 ° C. or higher, preferably 80 ° C. or higher, and usually 300 ° C. or lower, preferably 280 ° C. or lower, more preferably 250 ° C. or lower. Is preferable (this step may be referred to as an annealing treatment step). By performing the annealing process at a temperature of 50 ° C. or higher, an effect of improving the adhesion between the layers of the photoelectric conversion element, for example, the adhesion between the electron extraction layer and the cathode and / or the electron extraction layer and the active layer is obtained. ,preferable. By improving the adhesion between the layers, the thermal stability and durability of the photoelectric conversion element can be improved. It is preferable to set the temperature of the annealing treatment step to 300 ° C. or lower because the possibility that the organic compound in the active layer is thermally decomposed is reduced. In the annealing treatment step, stepwise heating may be performed within the above temperature range.

  The heating time is usually 1 minute or longer, preferably 3 minutes or longer, and usually 3 hours or shorter, preferably 1 hour or shorter. The annealing treatment step is preferably terminated when the open-circuit voltage, the short-circuit current, and the fill factor, which are parameters of the solar cell performance, reach a constant value. Further, the annealing treatment step is preferably performed under normal pressure and in an inert gas atmosphere.

  The heating method is not particularly limited, but it is preferable to introduce the photoelectric conversion element into a conventionally known heating atmosphere such as hot air or far infrared rays.

<3-3. Buffer layer>
The organic thin-film solar cell element according to the embodiment of the present invention usually has an electron extraction layer between the cathode and the active layer. The organic thin film solar cell element has a hole extraction layer between the active layer and the anode. The electron extraction layer and the hole extraction layer are not essential.

  The electron extraction layer and the hole extraction layer are preferably disposed so as to sandwich the active layer between the pair of electrodes. That is, when the organic thin-film solar cell element includes both an electron extraction layer and a hole extraction layer, the upper electrode, the hole extraction layer, the active layer, the electron extraction layer, and the lower electrode can be arranged in this order. When the organic thin film solar cell element includes an electron extraction layer and does not include a hole extraction layer, the upper electrode, the active layer, the electron extraction layer, and the lower electrode can be disposed in this order. The stacking order of the electron extraction layer and the hole extraction layer may be reversed, or at least one of the electron extraction layer and the hole extraction layer may be composed of a plurality of different films.

<3-3-1. Electron extraction layer>
The material of the electron extraction layer is not particularly limited as long as it is a material that improves the efficiency of extracting electrons from the active layer to the cathode, and examples thereof include inorganic compounds and organic compounds.

  Examples of the material of the inorganic compound include salts of alkali metals such as Li, Na, K or Cs; n-type semiconductor oxides such as titanium oxide (TiOx) and zinc oxide (ZnO). Among them, the alkali metal salt is preferably a fluoride salt such as LiF, NaF, KF or CsF, and the n-type semiconductor oxide is preferably zinc oxide (ZnO). The operation mechanism of such a material is unknown, but it is conceivable to reduce the work function of the cathode when combined with a cathode made of Al or the like and increase the voltage applied to the inside of the solar cell element.

  Examples of organic compound materials include, for example, phosphine compounds having a double bond between a phosphorus atom and a group 16 element such as triarylphosphine oxide compounds; bathocuproin (BCP) or bathophenanthrene (Bphen), A phenanthrene compound which may have a substituent and may be substituted at the 1-position and the 10-position with a heteroatom; a boron compound such as triarylboron; and (8-hydroxyquinolinato) aluminum (Alq3) Organometallic oxide; Compound having 1 or 2 ring structure which may have a substituent such as oxadiazole compound or benzimidazole compound; Naphthalenetetracarboxylic anhydride (NTCDA) or perylenetetracarboxylic acid Of dicarboxylic anhydrides, such as anhydrides (PTCDA) Aromatic compounds having Unachijimigo dicarboxylic acid structure.

  The LUMO energy level of the material of the electron extraction layer is not particularly limited, but is usually −4.0 eV or more, preferably −3.9 eV or more. On the other hand, it is usually −1.9 eV or less, preferably −2.0 eV or less. It is preferable that the LUMO energy level of the material for the electron extraction layer is −1.9 eV or less because charge transfer can be promoted. It is preferable that the LUMO energy level of the material for the electron extraction layer is −4.0 eV or more in terms of preventing reverse electron transfer to the n-type semiconductor material.

  The HOMO energy level of the material for the electron extraction layer is not particularly limited, but is usually −9.0 eV or more, preferably −8.0 eV or more. On the other hand, it is usually −5.0 eV or less, preferably −5.5 eV or less. The HOMO energy level of the material for the electron extraction layer is preferably −5.0 eV or less from the viewpoint of preventing movement of holes.

  As a method for calculating the LUMO energy level and the HOMO energy level of the material of the electron extraction layer, a cyclic voltammogram measurement method may be mentioned. For example, it can implement with reference to the method as described in well-known literature (International Publication 2011/016430).

  When the material of the electron extraction layer is an organic compound, the glass transition temperature (hereinafter sometimes referred to as Tg) of this compound as measured by the DSC method is not particularly limited, but is not observed, or It is preferable that it is 55 degreeC or more. That the glass transition temperature is not observed by the DSC method means that there is no glass transition temperature. Specifically, the determination is made based on the presence or absence of a glass transition temperature of 400 ° C. or lower. A material in which the glass transition temperature by the DSC method is not observed is preferable in that it has high thermal stability.

  Among the compounds having a glass transition temperature of 55 ° C. or higher as measured by the DSC method, the glass transition temperature is preferably 65 ° C. or higher, more preferably 80 ° C. or higher, more preferably 110 ° C. or higher, particularly preferably. Compounds that are 120 ° C. or higher are desirable. On the other hand, the upper limit of the glass transition temperature is not particularly limited, but is usually 400 ° C. or lower, preferably 350 ° C. or lower, more preferably 300 ° C. or lower. Moreover, it is preferable that the material of an electron taking-out layer is a thing by which the glass transition temperature by DSC method is not observed below 30 degreeC or more and less than 55 degree | times.

  The glass transition temperature in the present specification is defined as a point at which specific heat changes in an amorphous solid, which is a temperature at which local molecular motion is started by thermal energy. When the temperature rises further than Tg, the solid structure changes and crystallization occurs (the temperature at this time is defined as the crystallization temperature (Tc)). When the temperature rises further, it generally melts at the melting point (Tm) and changes to a liquid state. However, these phase transitions may not be observed due to molecular decomposition or sublimation at high temperatures.

The DSC method is a thermophysical property measurement method (differential scanning calorimetry method) defined in JIS K-0129 “General Rules for Thermal Analysis”. In order to determine the glass transition temperature more clearly, it is desirable to measure after rapidly cooling a sample once heated to a temperature higher than the glass transition temperature. For example, the measurement can be carried out by a method described in a known document (International Publication No. 2011/016430).

  When the glass transition temperature of the compound used for the electron extraction layer is 55 ° C. or higher, the structure of this compound is difficult to change against external stress such as applied electric field, flowing current, stress due to bending or temperature change. It is preferable in terms of durability. Furthermore, since there is a tendency that the crystallization of the thin film of the compound does not proceed easily, the stability of the electron extraction layer is improved by making it difficult for the compound to change between the amorphous state and the crystalline state in the operating temperature range. Therefore, it is preferable in terms of durability. This effect becomes more prominent as the glass transition temperature of the material is higher.

The thickness of the electron extraction layer is not particularly limited, but is usually 0.01 nm or more, preferably 0.1 nm or more, more preferably 0.5 nm or more. On the other hand, it is usually 400 nm or less, preferably 200 nm or less. When the film thickness of the electron extraction layer 102 is 0.01 nm or more, it functions as a buffer material. When the film thickness of the electron extraction layer is 40 nm or less, electrons are easily extracted, and the photoelectric conversion efficiency Can be improved.
There is no restriction | limiting in the formation method of an electronic taking-out layer. For example, when a material having sublimation property is used, it can be formed by a vacuum deposition method or the like. Further, for example, when a material soluble in a solvent is used, it can be formed by a wet coating method such as spin coating or inkjet.

  When the electron extraction layer is formed by a coating method, a surfactant may be further contained in the coating solution. By using the surfactant, the occurrence of dents due to adhesion of fine bubbles or foreign matters and / or uneven coating in the drying process is suppressed. Known surfactants (cationic surfactants, anionic surfactants, nonionic surfactants) can be used as the surfactant. Of these, silicon-based surfactants, acetylenic diol-based surfactants, and fluorine-based surfactants are preferable. In addition, as surfactant, only 1 type may be used and 2 or more types may be used together by arbitrary combinations and a ratio.

<3-3-2. Hole extraction layer>
There is no particular limitation on the material of the hole extraction layer, and any material can be used as long as it can improve the efficiency of extracting holes from the active layer to the anode. Specifically, polythiophene, polypyrrole, polyacetylene, triphenylenediamine, polyaniline, or the like, a conductive polymer doped with sulfonic acid and / or iodine, a polythiophene derivative having a sulfonyl group as a substituent, or a conductive organic such as arylamine Examples thereof include compounds, copper oxide, nickel oxide, manganese oxide, molybdenum oxide, vanadium oxide, metal oxide such as tungsten oxide, Nafion, and a p-type semiconductor described later. Among them, a conductive polymer doped with sulfonic acid is preferable, and (3,4-ethylenedioxythiophene) poly (styrenesulfonic acid) (PEDOT: PSS) in which a polythiophene derivative is doped with polystyrene sulfonic acid is more preferable. It is. A thin film of metal such as gold, indium, silver or palladium can also be used. A thin film of metal or the like may be formed alone or in combination with the above organic material.

  The thickness of the hole extraction layer is not particularly limited, but is usually 0.2 nm or more. On the other hand, it is usually 400 nm or less, preferably 200 nm or less. When the film thickness of the hole extraction layer is 0.2 nm or more, it functions as a buffer material. When the film thickness of the hole extraction layer is 400 nm or less, holes are easily extracted, Conversion efficiency can be improved.

There is no restriction | limiting in the formation method of a positive hole taking-out layer. For example, when a material having sublimation property is used, it can be formed by a vacuum deposition method or the like. Further, for example, when a material soluble in a solvent is used, it can be formed by roll coating, die coating, a wet coating method such as an inkjet method, or the like. When a semiconductor material is used for the hole extraction layer, the precursor may be converted into a semiconductor compound after forming the layer using the precursor, similarly to the low-molecular organic semiconductor compound of the organic active layer described later.

Especially, when using PEDOT: PSS as a material of a hole taking-out layer, it is preferable to form a hole taking-out layer by the method of apply | coating a dispersion liquid. PEDOT: The dispersion of PSS, and CLEVIOS ^TM series of Heraeus, Inc., include Agfa Corp. of ORGACON ^TM series and the like.

  When the hole extraction layer is formed by a coating method, a surfactant may be further contained in the coating solution. By using the surfactant, the occurrence of dents due to adhesion of fine bubbles or foreign matters and / or uneven coating in the drying process is suppressed. Known surfactants (cationic surfactants, anionic surfactants, nonionic surfactants) can be used as the surfactant. Of these, silicon-based surfactants, acetylenic diol-based surfactants, and fluorine-based surfactants are preferable. In addition, as surfactant, only 1 type may be used and 2 or more types may be used together by arbitrary combinations and a ratio.

<3-4. Active layer>
The active layer refers to a layer in which photoelectric conversion is performed, and usually includes a p-type semiconductor compound and an n-type semiconductor compound. The p-type semiconductor compound is a compound that works as a p-type semiconductor material, and the n-type semiconductor compound is a compound that works as an n-type semiconductor material. When the organic thin film solar cell element receives light, the light is absorbed by the active layer, electricity is generated at the interface between the p-type semiconductor compound and the n-type semiconductor compound, and the generated electricity is extracted from the electrode.

  As the layer structure of the active layer, a thin film stacked type in which a p-type semiconductor compound layer and an n-type semiconductor compound layer are stacked, a bulk heterojunction type having a layer in which a p-type semiconductor compound and an n-type semiconductor compound are mixed, and p-type Examples thereof include a semiconductor compound layer, a layer (i layer) in which a p-type semiconductor compound and an n-type semiconductor compound are mixed, and an n-type semiconductor compound layer laminated. Among these, a bulk heterojunction type having a layer in which a p-type semiconductor compound and an n-type semiconductor compound are mixed is preferable.

  The thickness of the active layer is not particularly limited, but is usually 10 nm or more, preferably 50 nm or more, and is usually 1000 nm or less, preferably 500 nm or less, more preferably 200 nm or less. It is preferable that the thickness of the active layer is 10 nm or more because the uniformity of the film is maintained and short-circuiting is less likely to occur. Moreover, it is preferable that the thickness of the active layer is 1000 nm or less from the viewpoint that the internal resistance is small and that the diffusion of charges is good without being too far apart from each other.

  A method for forming the active layer is not particularly limited, but a coating method is preferable. As the coating method, any method can be used.For example, reverse roll coating method, gravure coating method, kiss coating method, roll brush method, spray coating method, air knife coating method, wire barber coating method, pipe doctor method, Examples of the method include impregnation / coating and curtain coating.

  For example, the p-type semiconductor compound layer and the n-type semiconductor compound layer can be produced by applying a coating liquid containing a p-type semiconductor compound or an n-type semiconductor compound. Moreover, the layer in which the p-type semiconductor compound and the n-type semiconductor compound are mixed can be prepared by applying a coating solution containing the p-type semiconductor compound and the n-type semiconductor compound. As will be described later, the semiconductor compound precursor may be converted into a semiconductor compound after the coating liquid containing the semiconductor compound precursor is applied.

<3-4-1. p-type semiconductor compound>
The p-type semiconductor compound included in the active layer is not particularly limited, and examples thereof include a low molecular organic semiconductor compound and a high molecular organic semiconductor compound.

<3-4-1-1. Low molecular organic semiconductor compound>
The molecular weight of the low-molecular organic semiconductor compound is not particularly limited both at the upper limit and the lower limit, but is usually 5000 or less, preferably 2000 or less, and is usually 100 or more, preferably 200 or more.

Further, the low molecular organic semiconductor compound preferably has crystallinity. A p-type semiconductor compound having crystallinity has a strong intermolecular interaction, and holes generated at the interface between the p-type semiconductor compound and the n-type semiconductor compound in the active layer can be efficiently transported to the anode. In the present specification, crystallinity is a property of a compound that takes a three-dimensional periodic arrangement with uniform orientation due to intermolecular interaction or the like. Examples of the crystallinity measuring method include an X-ray diffraction method (XRD) and a field effect mobility measuring method. In particular, in the field effect mobility measurement, the hole mobility is preferably 1.0 × 10 ⁻⁵ cm ² / Vs or more, and more preferably 1.0 × 10 ⁻⁴ cm ² / Vs or more. On the other hand, the hole mobility is usually preferably 1.0 × 10 ⁴ cm ² / Vs or less, more preferably 1.0 × 10 ³ cm ² / Vs or less, and 1.0 × 10 ² cm. More preferably, it is ² / Vs or less.

  The low-molecular organic semiconductor compound is not particularly limited as long as it can function as a p-type semiconductor material. Specifically, condensed aromatic hydrocarbons such as naphthacene, pentacene, or pyrene; α-sexithiophene, etc. Oligothiophenes containing 4 or more thiophene rings; including at least one of thiophene ring, benzene ring, fluorene ring, naphthalene ring, anthracene ring, thiazole ring, thiadiazole ring and benzothiazole ring, and a total of 4 or more linked A phthalocyanine compound and a metal complex thereof, or a porphyrin compound such as tetrabenzoporphyrin and a macrocycle such as a metal complex thereof. Preferably, they are a phthalocyanine compound and its metal complex, or a porphyrin compound and its metal complex.

Examples of the porphyrin compound and its metal complex (Z ¹ in the figure is CH), and the phthalocyanine compound and its metal complex (Z ¹ in the figure is N) include compounds having the following structures.

Here, M represents a metal or two hydrogen atoms, and the metal includes a divalent metal such as Cu, Zn, Pb, Mg, Pd, Ag, Co, or Ni, and an axial ligand 3 Metals having a valence higher than that, for example, TiO, VO, SnCl ₂ , AlCl, InCl, Si, and the like are also included.

R ^{11 to} R ¹⁴ are each independently a hydrogen atom or an alkyl group having 1 to 24 carbon atoms. The alkyl group having 1 to 24 carbon atoms is a saturated or unsaturated chain hydrocarbon group having 1 to 24 carbon atoms or a saturated or unsaturated cyclic hydrocarbon group having 3 to 24 carbon atoms. Among these, a saturated or unsaturated chain hydrocarbon group having 1 to 12 carbon atoms or a saturated or unsaturated cyclic hydrocarbon group having 3 to 12 carbon atoms is preferable.

  Among the phthalocyanine compounds and metal complexes thereof, 29H, 31H-phthalocyanine, copper phthalocyanine complex, zinc phthalocyanine complex, titanium phthalocyanine oxide complex, magnesium phthalocyanine complex, lead phthalocyanine complex or copper 4,4 ′, 4 ″, 4 '' '-Tetraaza-29H, 31H-phthalocyanine complex, more preferably 29H, 31H-phthalocyanine or copper phthalocyanine complex. One of the above compounds may be used, or a mixture of a plurality of compounds may be used.

  Among the porphyrin compounds and metal complexes thereof, 5,10,15,20-tetraphenyl-21H, 23H-porphine, 5,10,15,20-tetraphenyl-21H, 23H-porphine cobalt (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine copper (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine zinc (II), 5,10,15,20- Tetraphenyl-21H, 23H-porphine nickel (II), 5,10,15,20-tetraphenyl-21H, 23H-porphine vanadium (IV) oxide, 5,10,15,20-tetra (4-pyridyl)- 21H, 23H-porphine, 29H, 31H-tetrabenzo [b, g, l, q] porphine, 2 H, 31H-tetrabenzo [b, g, l, q] porphine cobalt (II), 29H, 31H-tetrabenzo [b, g, l, q] porphine copper (II), 29H, 31H-tetrabenzo [b, g, l, q] porphine zinc (II), 29H, 31H-tetrabenzo [b, g, l, q] porphine nickel (II) or 29H, 31H-tetrabenzo [b, g, l, q] porphine vanadium (IV) oxide And preferably 5,10,15,20-tetraphenyl-21H, 23H-porphine or 29H, 31H-tetrabenzo [b, g, l, q] porphine. One of the above compounds may be used, or a mixture of a plurality of compounds may be used.

  Examples of the method for forming a low molecular organic semiconductor compound include a vapor deposition method and a coating method. The latter is preferred because of the process advantage that coating can be formed. When the coating method is used, there is a method of converting a low molecular organic semiconductor compound precursor into a low molecular organic semiconductor compound after coating. A method using a semiconductor compound precursor is more preferable in that coating film formation is easier.

  A low molecular organic semiconductor compound precursor is a compound that changes its chemical structure and is converted into a low molecular organic semiconductor compound by applying an external stimulus such as heating or light irradiation. The low molecular organic semiconductor compound precursor is preferably excellent in film formability. In particular, in order to be able to apply the coating method, the precursor itself may be applied in a liquid state, or the precursor may be applied in a solvent with high solubility by being dissolved in some solvent. preferable. For this reason, the solubility with respect to the solvent of a low molecular organic-semiconductor compound precursor is usually 0.1 weight% or more, Preferably it is 0.5 weight% or more, More preferably, it is 1 weight% or more. On the other hand, the upper limit is not particularly limited, but is usually 50% by weight or less, preferably 40% by weight or less.

The type of the solvent is not particularly limited as long as it can uniformly dissolve or disperse the semiconductor precursor compound. For example, aliphatic hydrocarbons such as hexane, heptane, octane, isooctane, nonane or decane; toluene, xylene , Aromatic hydrocarbons such as cyclohexylbenzene, chlorobenzene or orthodichlorobenzene; lower alcohols such as methanol, ethanol or propanol; ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; ethyl acetate, butyl acetate or methyl lactate Esters such as: Chloroform, methylene chloride, dichloroethane, trichloroethane, trichloroethylene, and other halogen hydrocarbons; Ethyl ether, tetrahydrofuran, dioxane, and other ethers; Dimethyl Formamide or amides such as dimethylacetamide and the like. Among them, preferably, aromatic hydrocarbons such as toluene, xylene, cyclohexylbenzene, chlorobenzene or orthodichlorobenzene; ketones such as acetone, methyl ethyl ketone, cyclopentanone or cyclohexanone; chloroform, methylene chloride, dichloroethane, trichloroethane or trichloroethylene Halogen hydrocarbons; ethers such as ethyl ether, tetrahydrofuran or dioxane. More preferably, non-halogen aromatic hydrocarbons such as toluene, xylene or cyclohexylbenzene; non-halogen ketones such as cyclopentanone or cyclohexanone; non-halogen aliphatic ethers such as tetrahydrofuran or 1,4-dioxane is there. Particularly preferred are non-halogen aromatic hydrocarbons such as toluene, xylene or cyclohexylbenzene. In addition, 1 type of solvent may be used independently and 2 or more types of solvents may be used together by arbitrary combinations and a ratio.

  Furthermore, it is preferable that the low molecular organic semiconductor compound precursor can be easily converted into a semiconductor compound. In the step of converting a low molecular organic semiconductor compound precursor to a semiconductor compound, which will be described later, what kind of external stimulus is given to the semiconductor precursor is arbitrary, but usually heat treatment or light treatment is performed. Preferably, it is heat treatment. In this case, the low-molecular organic semiconductor compound precursor preferably has a solvophilic group with respect to a predetermined solvent, which can be eliminated by a reverse Diels-Alder reaction as a part of the skeleton.

  Moreover, it is preferable that a low molecular organic-semiconductor compound precursor is converted into a semiconductor compound with a high yield through a conversion process. In this case, the yield of the semiconductor compound obtained by conversion from the low molecular organic semiconductor compound precursor is arbitrary as long as the performance of the photoelectric conversion element is not impaired, but the low molecular organic semiconductor obtained from the low molecular organic semiconductor compound precursor The yield of the compound is usually 90 mol% or more, preferably 95 mol% or more, more preferably 99 mol% or more.

  The low molecular organic semiconductor compound precursor is not particularly limited as long as it has the above characteristics, and specifically, compounds described in JP-A-2007-324587 can be used. Particularly preferred examples include compounds represented by the following formula.

In the above formula, at least one of D ¹ and D ² represents a group that forms a π-conjugated divalent aromatic ring, Z ² —Z ³ is a group that can be removed by heat or light, and Z ² A π-conjugated compound obtained by elimination of —Z ³ represents a low molecular organic semiconductor compound. In addition, D ¹ and D ² which are not a group that forms a π-conjugated divalent aromatic ring represent a substituted or unsubstituted ethenylene group.

In the compound represented by the above formula, Z ² —Z ³ is eliminated by heat or light as shown in the following chemical reaction formula to form a π-conjugated compound having high planarity. This produced π-conjugated compound is a low-molecular organic semiconductor compound. This low molecular organic semiconductor compound is used as a material having p-type semiconductor characteristics.

  The following are mentioned as an example of a low molecular organic-semiconductor compound precursor. In the following, t-Bu represents a t-butyl group, and M is the same as described for porphyrin and phthalocyanine.

  Specific examples of the conversion of the low-molecular organic semiconductor compound precursor into the low-molecular organic semiconductor compound include the following.

  The low molecular organic semiconductor compound precursor may have a structure in which positional isomers exist, and in that case, it may be a mixture of a plurality of positional isomers. A mixture of a plurality of positional isomers is preferable because it has a higher solubility in a solvent than a low-molecular organic semiconductor compound precursor composed of a single positional isomer component, and is easy to form a coating film. The reason why the solubility of the mixture of multiple positional isomers is high is that the detailed mechanism is not clear, but the crystallinity of the compound itself is potentially retained, but the mixture of multiple isomers is mixed in the solution. It is assumed that three-dimensional regular intermolecular interaction becomes difficult. The solubility of the mixture of a plurality of regioisomers in a non-halogen solvent is usually 0.1% by weight or more, preferably 1% by weight or more, more preferably 5% by weight or more. Although there is no restriction | limiting in an upper limit, Usually, it is 50 weight% or less, More preferably, it is 40 weight% or less.

<3-4-1-2. Polymer Organic Semiconductor Compound>
The polymer organic semiconductor compound is not particularly limited, and is a conjugated polymer semiconductor such as polythiophene, polyfluorene, polyphenylene vinylene, polythienylene vinylene, polyacetylene or polyaniline; a polymer such as oligothiophene substituted with an alkyl group or other substituents Semiconductor; and the like. Moreover, the semiconductor polymer which copolymerized 2 or more types of monomer units is also mentioned. The conjugated polymers, ^{e.g., Handbook of Conducting Polymers, 3 rd} Ed. (2 volumes), 2007, Materials Science and Engineering, 2001, 32, 1-40, Pure Appl. Chem. Use polymers that can be synthesized by a combination of polymers described in known literature such as 2002, 74, 2031-3044, Handbook of THIOPHENE-BASED MATERIALS (2 volumes), 2009, and derivatives thereof, and combinations of the described monomers. Can do. The polymer organic semiconductor compound used as the p-type semiconductor compound may be a single compound or a mixture of a plurality of compounds.

The monomer skeleton and monomer substituent of the polymer organic semiconductor compound can be selected to control the solubility, crystallinity, film-forming property, HOMO energy level, LUMO energy level, and the like. Moreover, it is preferable that a high molecular organic-semiconductor compound is soluble in the organic solvent at the point which can form an active layer by the apply | coating method when producing a photoelectric conversion element. Specific examples of the polymer organic semiconductor compound include the following, but are not limited thereto.

  Among the p-type semiconductor compounds, the low-molecular organic semiconductor compound is preferably a condensed aromatic hydrocarbon such as naphthacene, pentacene, or pyrene, a phthalocyanine compound and a metal complex thereof, or a porphyrin compound such as tetrabenzoporphyrin (BP) and The metal complex and the polymer organic semiconductor compound is a conjugated polymer semiconductor such as polythiophene. The p-type semiconductor compound used in the active layer may be a single compound or a mixture of multiple compounds.

  The low-molecular organic semiconductor compound and / or the high-molecular organic semiconductor compound may have some self-organized structure in the film-formed state, or may be in an amorphous state.

  The HOMO (highest occupied molecular orbital) energy level of the p-type semiconductor compound is not particularly limited, and can be selected according to the type of the n-type semiconductor compound described later. In particular, when a fullerene compound is used as an n-type semiconductor compound, the HOMO energy level of the p-type semiconductor compound is usually −5.7 eV or more, more preferably −5.5 eV or more, on the other hand, usually −4.6 eV or less. Preferably it is -4.8 eV or less. When the HOMO energy level of the p-type semiconductor compound is −5.7 eV or more, the characteristics as a p-type semiconductor are improved, and when the HOMO energy level of the p-type semiconductor compound is −4.6 eV or less, Stability is improved and the open circuit voltage (Voc) is also improved.

  The LUMO (lowest unoccupied molecular orbital) energy level of the p-type semiconductor compound is not particularly limited, but can be selected according to the type of the n-type semiconductor compound described later. In particular, when a fullerene compound is used as an n-type semiconductor compound, the LUMO energy level of the p-type semiconductor compound is usually −3.7 eV or more, preferably −3.6 eV or more. On the other hand, it is usually −2.5 eV or less, preferably −2.7 eV or less. When the LUMO energy level of the p-type semiconductor is −2.5 eV or less, the band gap is adjusted, light energy having a long wavelength can be effectively absorbed, and the short-circuit current density is improved. When the LUMO energy level of the p-type semiconductor compound is −3.7 eV or more, electron transfer to the n-type semiconductor compound is likely to occur and the short-circuit current density is improved.

<3-4-2. N-type semiconductor compound>
The n-type semiconductor compound is not particularly limited. Specifically, it is a fullerene compound, a quinolinol derivative metal complex represented by 8-hydroxyquinoline aluminum; a condensed ring such as naphthalenetetracarboxylic acid diimide or perylenetetracarboxylic acid diimide. Tetracarboxylic acid diimides; perylene diimide derivatives, terpyridine metal complexes, tropolone metal complexes, flavonol metal complexes, perinone derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazole derivatives, benzthiazole derivatives, benzothiadiazole derivatives, oxadiazole derivatives, thiadiazoles Derivatives, triazole derivatives, aldazine derivatives, bisstyryl derivatives, pyrazine derivatives, phenanthroline derivatives, quinoxaline derivatives, benzoquinoline derivatives Bipyridine derivatives, borane derivatives, anthracene, pyrene, total fluoride condensed polycyclic aromatic hydrocarbons such as naphthacene or pentacene; single-walled carbon nanotubes, and the like.

  Among them, fullerene compounds, borane derivatives, thiazole derivatives, benzothiazole derivatives, benzothiadiazole derivatives, N-alkyl-substituted naphthalenetetracarboxylic acid diimides and N-alkyl-substituted perylene diimide derivatives are preferable, and fullerene compounds, N- Alkyl substituted perylene diimide derivatives and N-alkyl substituted naphthalene tetracarboxylic acid diimides are more preferred. One of the above compounds may be used, or a mixture of a plurality of compounds may be used. Examples of the n-type semiconductor compound include an n-type polymer semiconductor compound.

  The LUMO energy level of the n-type semiconductor compound is not particularly limited. For example, the value with respect to the vacuum level calculated by the cyclic voltammogram measurement method is usually −3.85 eV or more, preferably −3.80 eV or more. . In order to efficiently transfer electrons from a p-type semiconductor compound to an n-type semiconductor compound, the relative relationship of LUMO energy levels between the p-type semiconductor compound and the n-type semiconductor compound is important. Specifically, the LUMO energy level of the p-type semiconductor compound is above the LUMO energy level of the n-type semiconductor compound by a predetermined value, in other words, the electron affinity of the n-type semiconductor compound is p-type semiconductor compound. It is preferable that a predetermined energy is larger than the electron affinity. Since the open circuit voltage (Voc) depends on the difference between the HOMO energy level of the p-type semiconductor compound and the LUMO energy level of the n-type semiconductor compound, increasing the LUMO of the n-type semiconductor compound tends to increase the Voc. On the other hand, the LUMO value is usually −1.0 eV or less, preferably −2.0 eV or less, more preferably −3.0 eV or less, and still more preferably −3.3 eV or less. By lowering the LUMO energy level of the n-type semiconductor compound, electrons tend to move and the short circuit current (Jsc) tends to increase.

  As a method for calculating the LUMO energy level of an n-type semiconductor compound, there are a theoretically calculated method and a method of actually measuring. Theoretically calculated methods include semi-empirical molecular orbital methods and non-empirical molecular orbital methods. Examples of the actual measurement method include an ultraviolet-visible absorption spectrum measurement method and a cyclic voltammogram measurement method. Among them, the cyclic voltammogram measurement method is preferable.

The HOMO energy level of the n-type semiconductor compound is not particularly limited, but is usually −5.0 eV or less, preferably −5.5 eV or less. On the other hand, it is usually −7.0 eV or more, preferably −6.6 eV or more. It is preferable that the HOMO energy level of the n-type semiconductor compound is −7.0 eV or more because light absorption of the n-type semiconductor compound can also be used for power generation. The HOMO energy level of the n-type semiconductor compound is preferably −5.0 eV or less from the viewpoint of preventing reverse movement of holes.

The electron mobility of the n-type semiconductor compound is not particularly limited, but is usually 1.0 × 10 ⁻⁶ cm ² / Vs or more, preferably 1.0 × 10 ⁻⁵ cm ² / Vs or more. 0 × 10 ⁻⁵ cm ² / Vs or more is more preferable, and 1.0 × 10 ⁻⁴ cm ² / Vs or more is more preferable. On the other hand, it is usually 1.0 × 10 ³ cm ² / Vs or less, preferably 1.0 × 10 ² cm ² / Vs or less, and more preferably 5.0 × 10 ¹ cm ² / Vs or less. When the electron mobility of the n-type semiconductor compound is 1.0 × 10 ⁻⁶ cm ² / Vs or more, effects such as improvement of the electron diffusion rate, short circuit current, and conversion efficiency of the organic thin film solar cell element can be obtained. This is preferable. As a method for measuring electron mobility, there is a field effect transistor (FET) method, which can be carried out by a method described in a known document (Japanese Patent Laid-Open No. 2010-045186).

  The solubility of the n-type semiconductor compound in toluene at 25 ° C. is usually 0.5% by weight or more, preferably 0.6% by weight or more, and more preferably 0.7% by weight or more. On the other hand, it is usually preferably 90% by weight or less, more preferably 80% by weight or less, and further preferably 70% by weight or less. When the solubility of the n-type semiconductor compound in toluene at 25 ° C. is 0.5% by weight or more, the dispersion stability of the n-type semiconductor compound in the solution is improved, and aggregation, sedimentation, separation, and the like are less likely to occur. Therefore, it is preferable.

Hereinafter, examples of preferable n-type semiconductor compounds will be described.
<3-4-2-1. Fullerene Compound>
As a fullerene compound, what has the partial structure represented by general formula (n1), (n2), (n3), and (n4) is mentioned as a preferable example.

In the above formula, FLN represents fullerene, which is a carbon cluster having a closed shell structure. The carbon number of fullerene is not particularly limited as long as it is an even number of usually 60 or more and 130 or less. Examples of fullerenes include C ₆₀ , C ₇₀ , C ₇₆ , C ₇₈ , C ₈₂ , C ₈₄ , C ₉₀ , C ₉₄ , C ₉₆ and higher carbon clusters having more carbon than these. . Among these, _C60 or _C70 is preferable. As fullerenes, carbon-carbon bonds on some fullerene rings may be broken. Moreover, some of the carbon atoms constituting the fullerene may be replaced with other atoms. Further, the fullerene may include a metal atom, a non-metal atom, or an atomic group composed of these in a fullerene cage.

a, b, c and d are integers, and the sum of a, b, c and d is usually 1 or more, and usually 5 or less, preferably 3 or less. The partial structures in (n1), (n2), (n3) and (n4) are bonded to the same 5-membered ring or 6-membered ring in the fullerene skeleton. In the general formula (n1), —R ²¹ and — (CH ₂ ) _L are bonded to two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton. . In the general formula (n2), -C (R ²⁵ ) (R ²⁶ ) -N (R ²⁷ ) -C with respect to two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton. (R ²⁸ ) (R ²⁹ ) — are added to form a 5-membered ring. In the general formula (n3), —C (R ³⁰ ) (R ³¹ ) —C—C—C (R) with respect to two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton. ³² ) (R ³³ ) — are added to form a 6-membered ring. In the general formula (n4), —C (R ³⁴ ) (R ³⁵ ) — is added to two adjacent carbon atoms on the same 5-membered ring or 6-membered ring in the fullerene skeleton to form a 3-membered ring. Forming. L is an integer of 1 to 8. L is preferably an integer of 1 to 4, more preferably an integer of 1 to 2.

R ²¹ in the general formula (n1) is an alkyl group having 1 to 14 carbon atoms which may have a substituent, an alkoxy group having 1 to 14 carbon atoms which may have a substituent, or a substituent. An aromatic group which may have a group.

  The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group or an isobutyl group, and even more preferably a methyl group or an ethyl group. . The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms, more preferably an alkoxy group having 1 to 6 carbon atoms, and particularly preferably a methoxy group or an ethoxy group. The aromatic group is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms, more preferably a phenyl group, a thienyl group, a furyl group, or a pyridyl group. More preferred are groups or thienyl groups.

  Although it does not specifically limit as a substituent which said alkyl group, an alkoxy group, and an aromatic group may have, A halogen atom or a silyl group is preferable. As the halogen atom, a fluorine atom is preferable. The silyl group is preferably a diarylalkylsilyl group, a dialkylarylsilyl group, a triarylsilyl group or a trialkylsilyl group, more preferably a dialkylarylsilyl group, and even more preferably a dimethylarylsilyl group.

R ^{22 to} R ²⁴ in the general formula (n1) may each independently have a hydrogen atom, an alkyl group having 1 to 14 carbon atoms which may have a substituent, or a substituent. It is an aromatic group.

As the alkyl group, an alkyl group having 1 to 10 carbon atoms is preferable, and a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, or an n-hexyl group is preferable. . The substituent that the alkyl group may have is preferably a halogen atom. As the halogen atom, a fluorine atom is preferable. The alkyl group substituted with a fluorine atom is preferably a perfluorooctyl group, a perfluorohexyl group or a perfluorobutyl group.

  The aromatic group is preferably an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms, more preferably a phenyl group, a thienyl group, a furyl group, or a pyridyl group. More preferred are groups or thienyl groups. The substituent that the aromatic group may have is not particularly limited, but is a fluorine atom, an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group having 1 to 14 carbon atoms, or a carbon atom having 1 to 14 carbon atoms. An alkoxy group or an aromatic group having 3 to 10 carbon atoms is preferred, a fluorine atom or an alkoxy group having 1 to 14 carbon atoms is more preferred, and a methoxy group, n-butoxy group or 2-ethylhexyloxy group is still more preferred. When the aromatic group has a substituent, the number is not limited, but is preferably 1 or more and 3 or less, and more preferably 1. When the aromatic group has a plurality of substituents, the types of the substituents may be different, but are preferably the same.

R ^{25 to} R ²⁹ in the general formula (n2) may each independently have a hydrogen atom, an alkyl group having 1 to 14 carbon atoms which may have a substituent, or a substituent. It is an aromatic group.

  The alkyl group is preferably a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-hexyl group or octyl group, and more preferably a methyl group. The substituent that the alkyl group may have is not particularly limited, but a halogen atom is preferable. As the halogen atom, a fluorine atom is preferable. The alkyl group substituted with a fluorine atom is preferably a perfluorooctyl group, a perfluorohexyl group or a perfluorobutyl group.

  As the aromatic group, an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms is preferable, a phenyl group or a pyridyl group is more preferable, and a phenyl group is further preferable. Although it does not specifically limit as a substituent which an aromatic group may have, Preferably they are a fluorine atom, a C1-C14 alkyl group, or a C1-C14 alkoxy group. The alkyl group may be substituted with a fluorine atom. More preferably, it is an alkoxy group having 1 to 14 carbon atoms, and more preferably a methoxy group. When it has a substituent, the number is not limited, but it is preferably 1 or more and 3 or less, more preferably 1. The types of substituents may be different, but are preferably the same.

Ar ¹ in the general formula (n3) is an optionally substituted aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms, preferably A phenyl group, a naphthyl group, a biphenyl group, a thienyl group, a furyl group, a pyridyl group, a pyrimidyl group, a quinolyl group or a quinoxalyl group, more preferably a phenyl group, a thienyl group or a furyl group.

  Although there is no limitation as a substituent which may have, an amino group which may be substituted with a fluorine atom, a chlorine atom, a hydroxyl group, a cyano group, a silyl group, a boryl group or an alkyl group, having 1 to 14 carbon atoms An alkyl group, an alkoxy group having 1 to 14 carbon atoms, an alkylcarbonyl group having 2 to 14 carbon atoms, an alkylthio group having 1 to 14 carbon atoms, an alkenyl group having 2 to 14 carbon atoms, and 2 to 14 carbon atoms An alkynyl group, an ester group having 2 to 14 carbon atoms, an arylcarbonyl group having 3 to 20 carbon atoms, an arylthio group having 2 to 20 carbon atoms, an aryloxy group having 2 to 20 carbon atoms, and 6 or more carbon atoms An aromatic hydrocarbon group having 20 or less or a heterocyclic group having 2 to 20 carbon atoms is preferable, a fluorine atom, an alkyl group having 1 to 14 carbon atoms, 1 or less carbon atoms 1 An alkoxy group, having 2 to 14 ester groups carbons, an alkyl group or having 3 to 20 arylcarbonyl group carbons of 2 to 14 carbon atoms and more preferable. The alkyl group having 1 to 14 carbon atoms may be substituted with 1 or 2 or more fluorine atoms.

  The alkyl group having 1 to 14 carbon atoms is preferably a methyl group, an ethyl group or a propyl group. The alkoxy group having 1 to 14 carbon atoms is preferably a methoxy group, an ethoxy group, or a propoxy group. The alkylcarbonyl group having 1 to 14 carbon atoms is preferably an acetyl group. The ester group having 2 to 14 carbon atoms is preferably a methyl ester group or an n-butyl ester group. The arylcarbonyl group having 3 to 20 carbon atoms is preferably a benzoyl group.

  When it has a substituent, the number is not limited, but it is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less. When there are a plurality of substituents, the types may be different, but are preferably the same.

R ^{30 to} R ³³ in the general formula (n3) each independently have a hydrogen atom, an alkyl group which may have a substituent, an amino group which may have a substituent, or a substituent. It is an optionally substituted alkoxy group or an optionally substituted alkylthio group. R ³⁰ or R ³¹ may be bonded to any one of R ³² and R ³³ to form a ring. As a structure in the case of forming a ring, the structure shown to the general formula (n5) which is a bicyclo structure which the aromatic group condensed is mentioned, for example.

F In the general formula (n5) has the same meaning as c, Z ⁴ is an oxygen atom, a sulfur atom, an amino group, an alkylene group or an arylene group. The alkylene group preferably has 1 to 2 carbon atoms. The arylene group preferably has 5 to 12 carbon atoms, and examples thereof include a phenylene group. The amino group may be substituted with an alkyl group having 1 to 6 carbon atoms such as a methyl group or an ethyl group. The alkylene group is an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or 2 to 20 carbon atoms. The aromatic heterocyclic group may be substituted. The arylene group is an alkoxy group having 1 to 6 carbon atoms such as a methoxy group, an aliphatic hydrocarbon group having 1 to 5 carbon atoms, an aromatic hydrocarbon group having 6 to 20 carbon atoms, or 2 to 20 carbon atoms. The aromatic heterocyclic group may be substituted.

  The structure represented by the formula (n5) is particularly preferably a structure represented by the following formula (n6) or formula (n7).

R ^{34 to} R ³⁵ in the general formula (n4) each independently have a hydrogen atom, an alkoxycarbonyl group, an alkyl group having 1 to 14 carbon atoms which may have a substituent, or a substituent. An aromatic group that may be present.

  The alkoxy group constituting the alkoxycarbonyl group is preferably an alkoxy group having 1 to 12 carbon atoms or a fluorinated alkoxy group having 1 to 12 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and a methoxy group. Ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, n-hexoxy group, octoxy group, 2-propylpentoxy group, 2-ethylhexoxy group, cyclohexylmethoxy group or benzyloxy group A methoxy group, an ethoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group or an n-hexoxy group is particularly preferable.

  As the alkyl group, a linear alkyl group having 1 to 8 carbon atoms is preferable, and an n-propyl group is more preferable. The substituent that the alkyl group may have is not particularly limited, but is preferably an alkoxycarbonyl group. The alkoxy group constituting the alkoxycarbonyl group is preferably an alkoxy group having 1 to 14 carbon atoms or a fluorinated alkoxy group, more preferably a hydrocarbon group having 1 to 14 carbon atoms, a methoxy group, an ethoxy group, n- Propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, n-hexoxy group, octoxy group, 2-propylpentoxy group, 2-ethylhexoxy group, cyclohexylmethoxy group or benzyloxy group are more preferable, methoxy group or n A butoxy group is particularly preferred.

  As the aromatic group, an aromatic hydrocarbon group having 6 to 20 carbon atoms or an aromatic heterocyclic group having 2 to 20 carbon atoms is preferable, and a phenyl group, a biphenyl group, a thienyl group, a furyl group, or a pyridyl group is preferable. More preferred are a phenyl group and a thienyl group. The substituent that the aromatic group may have is preferably an alkyl group having 1 to 14 carbon atoms, a fluorinated alkyl group having 1 to 14 carbon atoms, or an alkoxy group having 1 to 14 carbon atoms. An alkoxy group having a number of 1 or more and 14 or less is more preferable, and a methoxy group or 2-ethylhexyloxy group is particularly preferable. When it has a substituent, the number is not limited, but it is preferably 1 or more and 3 or less, more preferably 1. The types of substituents may be different or the same, preferably the same.

As the structure of the general formula (n4), preferably R ³⁴ and R ³⁵ are both alkoxycarbonyl groups, R ³⁴ and R ³⁵ are both aromatic groups, or R ³⁴ is an aromatic group and R ^{And those in which 35} is a 3- (alkoxycarbonyl) propyl group.

  As the fullerene compound, one kind of the above compounds may be used, or a mixture of plural kinds of compounds may be used.

  In order to form a fullerene compound by a coating method, it is preferable that the fullerene compound itself can be applied in a liquid state, or that the fullerene compound is highly soluble in some solvent and can be applied as a solution. As a preferable range of solubility, the solubility in toluene at 25 ° C. is usually 0.1% by weight or more, preferably 0.4% by weight or more, more preferably 0.7% by weight or more. It is preferable that the solubility of the fullerene compound is 0.1% by weight or more because the dispersion stability of the fullerene compound in the solution increases and aggregation, sedimentation, separation, and the like are less likely to occur.

  The solvent for dissolving the fullerene compound is not particularly limited as long as it is a nonpolar organic solvent, but a non-halogen solvent is preferable. Although it is possible to use a halogen-based solvent such as dichlorobenzene, an alternative is demanded from the viewpoint of environmental load. Examples of non-halogen solvents include non-halogen aromatic hydrocarbons. Of these, toluene, xylene, cyclohexylbenzene, and the like are preferable.

  Although there is no restriction | limiting in particular as a manufacturing method of a fullerene compound, For example, the synthesis | combination of the fullerene compound which has a partial structure (n1) is international publication 2008/059771 or J.N. Am. Chem. Soc. , 2008, 130 (46), 15429-15436.

  Synthesis of fullerene compounds having a partial structure (n2) is described in J. Org. Am. Chem. Soc. 1993, 115, 9798-9799, Chem. Mater. 2007, 19, 5363-5372 and Chem. Mater. It can be carried out according to the description of known documents such as 2007, 19, 5194-5199.

  Synthesis of a fullerene compound having a partial structure (n3) is described in Angew. Chem. Int. Ed. Engl. 1993, 32, 78-80, Tetrahedron Lett. It can be carried out according to the description of known documents such as 1997, 38, 285-288, WO 2008/018931 and WO 2009/086212.

  Synthesis of fullerene compounds having a partial structure (n4) is described in J. Org. Chem. Soc. Perkin Trans. 1, 1997 1595, Thin Solid Films 489 (2005) 251-256, Adv. Funct. Mater. 2005, 15, 1979-1987 and J. Org. Org. Chem. It can be carried out according to the description of known documents such as 1995, 60, 532-538.

<3-4-2-2. N-alkyl-substituted perylene diimide derivatives>
N-alkyl-substituted perylene diimide derivatives are not particularly limited, and specifically, International Publication No. 2008/063609, International Publication No. 2009/115553, International Publication No. 2009/098250, International Publication No. Examples thereof include compounds described in 2009/000756 and International Publication No. 2009/091670. These compounds are preferable in that they have high electron mobility and can absorb light in the visible range, and thus can contribute to both charge transport and power generation.

<3-4-2-3. Naphthalenetetracarboxylic acid diimide>
The naphthalenetetracarboxylic acid diimide is not particularly limited, and specific examples thereof include compounds described in International Publication No. 2008/063609, International Publication No. 2007/146250 and International Publication No. 2009/000756. It is done. These compounds are preferable because they have high electron mobility, high solubility, and excellent coating properties.

<3-4-2-4. n-type Polymer Semiconductor Compound>
There are no particular restrictions on the n-type polymer semiconductor compound, but condensed ring tetracarboxylic acid diimides such as naphthalenetetracarboxylic acid diimide and perylenetetracarboxylic acid diimide, perylene diimide derivatives, benzimidazole derivatives, benzoxazole derivatives, thiazoles N-type polymer semiconductor comprising at least one of a derivative, a benzothiazole derivative, a benzothiadiazole derivative, an oxadiazole derivative, a thiadiazole derivative, a triazole derivative, a pyrazine derivative, a phenanthroline derivative, a quinoxaline derivative, a bipyridine derivative and a borane derivative Compounds and the like.

  Among them, a polymer having at least one of a borane derivative, a thiazole derivative, a benzothiazole derivative, a benzothiadiazole derivative, an N-alkyl-substituted naphthalenetetracarboxylic acid diimide and an N-alkyl-substituted perylene diimide derivative as a constituent unit is provided. Preferably, an n-type polymer semiconductor compound having at least one of N-alkyl-substituted perylene diimide derivative and N-alkyl-substituted naphthalenetetracarboxylic acid diimide as a constituent unit is more preferable. One of the above compounds may be used as the n-type polymer semiconductor compound, or a mixture of a plurality of compounds may be used.

Specific examples of the n-type polymer semiconductor compound include compounds described in International Publication No. 2009/098253, International Publication No. 2009/098250, International Publication No. 2010/012710, and International Publication No. 2009/098250. Can be mentioned. Since these compounds can absorb light in the visible range, they can contribute to power generation, are preferred because of their high viscosity and excellent coating properties.
Of the 5-3 buffer layer and the 5-4 active layer, the layer containing an organic component is collectively referred to as an organic layer, and the thickness of the organic layer is preferably 1.8 μm or less, and 0.6 μm. The following is more preferable.

<3-5. Photoelectric conversion characteristics>
The photoelectric conversion characteristics of the organic thin film solar cell element can be obtained as follows. The organic thin-film solar cell element is irradiated with AM1.5G light with a solar simulator at an irradiation intensity of 100 mW / cm ² to measure current-voltage characteristics. From the obtained current-voltage curve, photoelectric conversion characteristics such as photoelectric conversion efficiency (PCE), short circuit current density (Jsc), open circuit voltage (Voc), fill factor (FF), series resistance, and shunt resistance can be obtained.

  The photoelectric conversion efficiency of the organic thin film solar cell element is not particularly limited, but is usually 1% or more, preferably 1.5% or more, and more preferably 2% or more. On the other hand, there is no particular limitation on the upper limit, and the higher the better.

Moreover, as a method for measuring the durability of the organic thin film solar cell element, there is a method for obtaining a maintenance rate of photoelectric conversion efficiency before and after the organic thin film solar cell element is exposed to the atmosphere.
(Maintenance rate) = (Photoelectric conversion efficiency after N hours of atmospheric exposure) / (Photoelectric conversion efficiency immediately before atmospheric exposure)

In order to put an organic thin-film solar cell element into practical use, it is important to have high photoelectric conversion efficiency and high durability in addition to simple and inexpensive manufacture. From this viewpoint, the maintenance rate of photoelectric conversion efficiency before and after exposure to the atmosphere for one week is preferably 60% or more, more preferably 80% or more, and the higher the better.

<4. Organic thin film solar cell module>
Next, an organic thin film solar cell module including an organic thin film solar cell element according to an embodiment of the present invention will be described with reference to the drawings. FIG. 3 is a diagram schematically showing the configuration of the organic thin film solar cell module. As shown in FIG. 3, the organic thin film solar cell module 14 of this embodiment includes a weather-resistant protective film 1, an ultraviolet cut film 2, a gas barrier film 3, a getter material film 4, a sealing material 5, and an organic material. The thin film solar cell element 6, the sealing material 7, the getter material film 8, the gas barrier film 9, and the back sheet 10 are provided in this order. And light is irradiated from the side (downward in the figure) where the weather-resistant protective film 1 was formed, and the organic thin-film solar cell element 6 generates electric power. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. Good.

<4-1. Weatherproof protective film 1>
The weather-resistant protective film 1 is a film that protects the organic thin-film solar cell element 6 from weather changes. By covering the organic thin-film solar cell element 6 with the weather-resistant protective film 1, the organic thin-film solar cell element 6 and the like are protected from weather changes and the power generation capacity is kept high. Since the weather-resistant protective film 1 is located on the outermost layer of the organic thin-film solar cell module 14, the weather-resistant protective film 1 of the organic thin-film solar cell module such as weather resistance, heat resistance, transparency, water repellency, contamination resistance and / or mechanical strength is used. It is preferable to have properties suitable for a surface coating material and to maintain it for a long period of time in outdoor exposure.

  Moreover, it is preferable that the weather-resistant protective film 1 transmits visible light from a viewpoint which does not prevent the light absorption of the organic thin-film solar cell element 6. For example, the transmittance of visible light (wavelength 360 to 830 nm) is preferably 80% or more, and the upper limit is not limited. Furthermore, since the organic thin film solar cell module 14 is often heated by receiving light, it is preferable that the weather-resistant protective film 1 also has heat resistance. From this viewpoint, the melting point of the constituent material of the weather-resistant protective film 1 is usually 100 ° C. or higher and 350 ° C. or lower.

  The material which comprises the weather-resistant protective film 1 is arbitrary if the organic thin-film solar cell element 6 can be protected from a weather change. Examples of the material include polyethylene resin, polypropylene resin, cyclic polyolefin resin, AS (acrylonitrile-styrene) resin, ABS (acrylonitrile-butadiene-styrene) resin, polyvinyl chloride resin, fluorine resin, polyethylene terephthalate, polyethylene Examples thereof include polyester resins such as naphthalate, phenol resins, polyacrylic resins, polyamide resins such as various nylons, polyimide resins, polyamide-imide resins, polyurethane resins, cellulose resins, silicon resins, and polycarbonate resins.

In addition, the weather-resistant protective film 1 may be formed with 1 type of material, and may be formed with 2 or more types of materials. Moreover, although the weather-resistant protective film 1 may be formed with the single layer film, the laminated | multilayer film provided with the film of two or more layers may be sufficient as it.
The thickness of the weather-resistant protective film 1 is not particularly defined, but is usually 10 μm or more and 200 μm or less.
Moreover, you may perform surface treatment, such as a corona treatment and / or a plasma treatment, for the weather-resistant protective film 1 in order to improve the adhesiveness with another film.

It is preferable to provide the weatherproof protective film 1 on the outer side of the organic thin film solar cell module 14 as much as possible. This is because more of the constituent members of the organic thin film solar cell module 14 can be protected.

<4-2. UV cut film 2>
The ultraviolet cut film 2 is a film that prevents the transmission of ultraviolet rays. The organic thin film solar cell element 6 and, if necessary, a gas barrier film are provided by providing the ultraviolet cut film 2 on the light receiving portion of the organic thin film solar cell module 14 and covering the light receiving surface 6a of the organic thin film solar cell element 6 with the ultraviolet cut film 2. 3, 9 etc. are protected from ultraviolet rays, and the power generation capacity can be kept high.

  The degree of the ability to suppress the transmission of ultraviolet rays required for the ultraviolet cut film 2 is preferably such that the transmittance of ultraviolet rays (for example, wavelength of 300 nm) is 50% or less, and there is no limit on the lower limit. Moreover, it is preferable that the ultraviolet cut film 2 transmits visible light from the viewpoint of not preventing the light absorption of the organic thin film solar cell element 6. For example, the transmittance of visible light (wavelength 360 to 830 nm) is preferably 80% or more, and the upper limit is not limited.

Furthermore, since the organic thin film solar cell module 14 is often heated by receiving light, the ultraviolet cut film 2 preferably has resistance to heat. From this viewpoint, the melting point of the constituent material of the ultraviolet cut film 2 is usually 100 ° C. or higher and 350 ° C. or lower.
Moreover, it is preferable that the ultraviolet cut film 2 is high in flexibility, has good adhesion to an adjacent film, and can cut water vapor and oxygen.

  The material which comprises the ultraviolet cut film 2 is arbitrary if the intensity | strength of an ultraviolet-ray can be weakened. Examples of the material include films formed by blending an ultraviolet absorber with an epoxy, acrylic, urethane, or ester resin. Further, a film in which a layer of an ultraviolet absorbent dispersed or dissolved in a resin (hereinafter referred to as “ultraviolet absorbing layer” as appropriate) is formed on a base film may be used.

Examples of the ultraviolet absorber that can be used include salicylic acid-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ones. In addition, a ultraviolet absorber may use 1 type and may use 2 or more types together by arbitrary combinations and a ratio. As described above, a film in which an ultraviolet absorbing layer is formed on a base film can also be used as the ultraviolet absorbing film. Such a film can be produced, for example, by applying a coating solution containing an ultraviolet absorber on a substrate film and drying it.
Although the material of a base film is not specifically limited, For example, polyester is mentioned at the point from which the balance of heat resistance and a softness | flexibility is obtained.

  Examples of specific products of the ultraviolet cut film 2 include cut ace (MKV Plastic Co., Ltd.). In addition, the ultraviolet cut film 2 may be formed with 1 type of material, and may be formed with 2 or more types of materials.

  Further, the ultraviolet cut film 2 may be formed of a single layer film, but may be a laminated film including two or more layers. The thickness of the ultraviolet cut film 2 is not particularly limited, but is usually 5 μm or more and 200 μm or less.

  Although the ultraviolet cut film 2 should just be provided in the position which covers at least one part of the light-receiving surface 6a of the organic thin film solar cell element 6, Preferably it is provided in the position which covers all the light-receiving surfaces 6a of the organic thin film solar cell element 6. FIG. However, the ultraviolet cut film 2 may be provided at a position other than the position covering the light receiving surface 6 a of the organic thin film solar cell element 6.

<4-3. Gas barrier film 3>
The gas barrier film 3 is a film that prevents permeation of water and oxygen. By covering the organic thin-film solar cell element 6 with the gas barrier film 3, the organic thin-film solar cell element 6 can be protected from water and oxygen, and the power generation capacity can be kept high.

The degree of moisture-proof capability required for the gas barrier film 3 varies depending on the type of the organic thin-film solar cell element 6 and the like, but the water vapor transmission rate per unit area (1 m ² ) per day is usually 1 × 10. It is preferably ⁻¹ g / m ² / day or less, and the lower limit is not limited.

The degree of oxygen permeability required for the gas barrier film 3 varies depending on the type of the organic thin film solar cell element 6 and the like, but the oxygen permeability per unit area (1 m ² ) is usually 1 ×. It is preferable that it is 10 < ^-1 > cc / m < ² > / day / atm or less, and there is no restriction | limiting in a minimum.

  Moreover, it is preferable that the gas barrier film 3 transmits visible light from the viewpoint of not preventing the organic thin film solar cell element 6 from absorbing light. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, and there is no upper limit.

  Furthermore, since the organic thin film solar cell module 14 is often heated by receiving light, the gas barrier film 3 preferably has heat resistance. From this viewpoint, the melting point of the constituent material of the gas barrier film 3 is usually 100 ° C. or higher and 350 ° C. or lower.

  The specific structure of the gas barrier film 3 is arbitrary as long as the organic thin-film solar cell element 6 can be protected from water. However, since the manufacturing cost increases as the amount of water vapor or oxygen that can permeate the gas barrier film 3 increases, it is preferable to use an appropriate film considering these points comprehensively.

Particularly suitable gas barrier film 3 includes, for example, a film obtained by vacuum-depositing SiO _x on a base film such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN).

In addition, the gas barrier film 3 may be formed with 1 type of material, and may be formed with 2 or more types of materials. The gas barrier film 3 may be formed of a single layer film, but may be a laminated film including two or more layers.
The thickness of the gas barrier film 3 is not particularly defined, but is usually 5 μm or more and 200 μm or less.

  As long as the gas barrier film 3 covers the organic thin film solar cell element 6 and can be protected from moisture and oxygen, the formation position is not limited, but the front surface of the organic thin film solar cell element 6 (surface on the light receiving surface side; lower side in FIG. 3). And the back surface (surface opposite to the light receiving surface; upper surface in FIG. 3). This is because the organic thin-film solar cell module 14 often has a front surface and a back surface formed in a larger area than the other surfaces. In this embodiment, the gas barrier film 3 covers the front surface of the organic thin film solar cell element 6, and a gas barrier film 9 described later covers the back surface of the organic thin film solar cell element 6. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. Good.

<4-4. Getter Material Film 4>
The getter material film 4 is a film that absorbs moisture and / or oxygen. By covering the organic thin film solar cell element 6 with the getter material film 4, the organic thin film solar cell element 6 and the like are protected from moisture and / or oxygen, and the power generation capacity is kept high. Here, unlike the gas barrier film 3 as described above, the getter material film 4 does not prevent moisture permeation but absorbs moisture. By using a film that absorbs moisture, when the organic thin-film solar cell element 6 is covered with the gas barrier film 3 or the like, the getter material film 4 captures moisture that slightly enters the space formed by the gas barrier films 3 and 9. Thus, the influence of moisture on the organic thin film solar cell element 6 can be eliminated.

The degree of moisture absorption capacity of the getter material film 4 is usually 0.1 mg / cm ² or more, and although there is no upper limit, it is usually 10 mg / cm ² or less. Further, when the organic thin film solar cell element 6 is covered with the gas barrier films 3 and 9 or the like by the getter material film 4 absorbing oxygen, oxygen that slightly enters the space formed by the gas barrier films 3 and 9 is absorbed. The getter material film 4 can capture and eliminate the influence of oxygen on the organic thin film solar cell element 6.

  Furthermore, it is preferable that the getter material film 4 transmits visible light from the viewpoint of not hindering the light absorption of the organic thin film solar cell element 6. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, and there is no upper limit.

  Furthermore, since the organic thin-film solar cell module 14 is often heated by receiving light, the getter material film 4 preferably has resistance to heat. From this viewpoint, the melting point of the constituent material of the getter material film 4 is usually 100 ° C. or higher and 350 ° C. or lower.

  The material constituting the getter material film 4 is arbitrary as long as it can absorb moisture and / or oxygen. Examples of the material include alkali metal, alkaline earth metal or alkaline earth metal oxides; alkali metal or alkaline earth metal hydroxides; silica gel, zeolitic compounds, magnesium sulfate. And sulfates such as sodium sulfate and nickel sulfate; and organometallic compounds such as aluminum metal complexes and aluminum oxide octylates. Specifically, examples of the alkaline earth metal include Ca, Sr, and Ba. Examples of the alkaline earth metal oxide include CaO, SrO, and BaO. In addition, Zr-Al-BaO and aluminum metal complexes are also included. Specific product names include, for example, OleDry (Futaba Electronics).

  Examples of the substance that absorbs oxygen include activated carbon, silica gel, activated alumina, molecular sieve, magnesium oxide, and iron oxide. In addition, Fe, Mn, Zn, and inorganic salts such as sulfates, chlorides, and nitrates of these metals are also included.

In addition, the getter material film 4 may be formed of one type of material or may be formed of two or more types of materials. The getter material film 4 may be formed of a single layer film, but may be a laminated film including two or more layers.
The thickness of the getter material film 4 is not particularly specified, but is usually 5 μm or more and 200 μm or less.

The formation position of the getter material film 4 is not limited as long as it is in the space formed by the gas barrier films 3 and 9, but the front surface (light receiving surface side surface of the organic thin film solar cell element 6; the lower side in FIG. 3). Surface) and back surface (surface opposite to the light receiving surface; upper surface in FIG. 3) is preferably covered. This is because the organic thin film solar cell module 14 often has a front surface and a back surface formed in a larger area than the other surfaces, and therefore moisture and oxygen tend to enter through these surfaces. From this viewpoint, the getter material film 4 is preferably provided between the gas barrier film 3 and the organic thin film solar cell element 6. In this embodiment, the getter material film 4 covers the front surface of the organic thin film solar cell element 6, the getter material film 8 described later covers the back surface of the organic thin film solar cell element 6, and the getter material films 4 and 8 are respectively organic thin film solar cells. It is located between the element 6 and the gas barrier films 3 and 9. In addition, when using a highly waterproof sheet such as a sheet in which a fluororesin film is bonded to both surfaces of an aluminum foil as the back sheet 10 described later, the getter material film 8 and / or the gas barrier film 9 may not be used depending on the application. Good.

<4-5. Sealing material 5>
The sealing material 5 is a film that reinforces the organic thin film solar cell element 6. Since the organic thin film solar cell element 6 is thin, the strength is usually weak, and thus the strength of the organic thin film solar cell module tends to be weak. However, the strength can be maintained high by the sealing material 5.

  Moreover, it is preferable that the sealing material 5 has high strength from the viewpoint of maintaining the strength of the organic thin-film solar cell module 14. The specific strength is related to the strength of the weatherproof protective film 1 other than the sealing material 5 and the strength of the back sheet 10 and is generally difficult to define, but the entire organic thin-film solar cell module 14 has good bending workability. It is desirable to have strength that does not cause peeling of the bent portion.

Moreover, it is preferable that the sealing material 5 permeate | transmits visible light from a viewpoint which does not prevent the light absorption of the organic thin film solar cell element 6. FIG. For example, the transmittance of visible light (wavelength 360 to 830 nm) is usually 60% or more, and there is no upper limit.
The thickness of the sealing material 5 is not particularly specified, but is usually 2 μm or more and 700 μm or less.

  The T-type peel adhesion strength of the sealing material 5 to the substrate is usually 1 N / inch or more and usually 2000 N / inch or less. It is preferable that the T-type peel adhesive strength is 1 N / inch or more in terms of ensuring the long-term durability of the module. It is preferable that the T-type peel adhesive strength is 2000 N / inch or less in that the base material, the barrier film, and the adhesive can be separated and discarded when the solar cell is discarded. The T-type peel adhesion strength is measured by a method according to JIS K6854.

  The constituent material of the sealing material 5 is not particularly limited as long as it has the above characteristics, but sealing of organic / inorganic solar cells, sealing of organic / inorganic LED elements, sealing of electronic circuit boards, etc. In general, a sealing material generally used can be used.

  Specifically, a thermosetting resin composition or a thermoplastic resin composition and an active energy ray curable resin composition can be mentioned. The active energy ray-curable resin composition is, for example, a resin that is cured by ultraviolet rays, visible light, electron beams, or the like. More specifically, an ethylene-vinyl acetate copolymer (EVA) resin composition, a hydrocarbon resin composition, an epoxy resin composition, a polyester resin composition, an acrylic resin composition, and a urethane resin composition. Or a silicon-based resin composition, etc., depending on the main chain, branched chain, terminal chemical modification of each polymer, adjustment of molecular weight, additives, etc., thermosetting, thermoplastic and active energy ray curable, etc. The characteristics are expressed.

  Moreover, since the organic thin-film solar cell module 14 is often heated by receiving light, it is preferable that the sealing material 5 also has heat resistance. From this viewpoint, the melting point of the constituent material of the sealing material 5 is usually 100 ° C. or higher and 350 ° C. or lower.

The density of the constituent material for sealing material in the sealing material 5 is preferably 0.80 g / cm ³ or more, and there is no upper limit. The measurement and evaluation of density can be performed by a method based on JIS K7112.

Although there is no restriction | limiting in the position which provides the sealing material 5, Usually, it provides so that the organic thin-film solar cell element 6 may be inserted | pinched. It is for protecting the organic thin film solar cell element 6 reliably. In this embodiment, the sealing material 5 and the sealing material 7 are provided on the front surface and the back surface of the organic thin film solar cell element 6, respectively.

<4-6. Organic Thin Film Solar Cell Element 6>
The organic thin film solar cell element 6 is the same as the organic thin film solar cell element 107 described above. That is, the organic thin film solar cell module 14 can be manufactured using the organic thin film solar cell element 107.

  Although only one organic thin film solar cell element 6 may be provided for each organic thin film solar cell module 14, two or more organic thin film solar cell elements 6 are usually provided. What is necessary is just to set the number of the specific organic thin film solar cell elements 6 arbitrarily. When a plurality of organic thin film solar cell elements 6 are provided, the organic thin film solar cell elements 6 are often arranged in an array.

  When a plurality of organic thin film solar cell elements 6 are provided, the organic thin film solar cell elements 6 are usually electrically connected to each other, and electricity generated from the group of connected organic thin film solar cell elements 6 is a terminal (not shown). In this case, the solar cell elements are usually connected in series in order to increase the voltage.

  Thus, when connecting the organic thin film solar cell elements 6 to each other, it is preferable that the distance between the organic thin film solar cell elements 6 is small, and as a result, between the organic thin film solar cell element 6 and the organic thin film solar cell element 6. The gap is preferably narrow. This is because the light receiving area of the organic thin film solar cell element 6 is widened to increase the amount of light received, and the amount of power generated by the organic thin film solar cell module 14 is increased.

<4-7. Sealing material 7>
The sealing material 7 is a film similar to the sealing material 5 described above, and the same material as the sealing material 7 can be used in the same manner except that the arrangement position is different. Moreover, since the constituent member on the back side of the solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

<4-8. Getter Material Film 8>
The getter material film 8 is the same film as the getter material film 4 described above, and the same material as the getter material film 4 can be used as necessary, except for the arrangement position. Moreover, since the constituent member on the back side of the organic thin film solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

<4-9. Gas barrier film 9>
The gas barrier film 9 is the same film as the gas barrier film 3 described above, and the same material as the gas barrier film 9 can be used as necessary except that the arrangement position is different. Moreover, since the constituent member on the back side of the organic thin film solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

<4-10. Back sheet 10>
The back sheet 10 is the same film as the weather-resistant protective film 1 described above, and the same material as the weather-resistant protective film 1 can be used in the same manner except that the arrangement position is different. In addition, if the back sheet 10 is difficult to permeate water and oxygen, the back sheet 10 can also function as a gas barrier layer. Moreover, since the constituent member on the back side of the organic thin film solar cell element 6 does not necessarily need to transmit visible light, a member that does not transmit visible light can be used.

<4-11. Dimensions>
The organic thin film solar cell module 14 using the organic thin film solar cell element according to this embodiment is usually a thin film member. Thus, by forming the organic thin film solar cell module 14 as a film-like member, the organic thin film solar cell module 14 can be easily installed in a building material, an automobile, an interior, or the like. The organic thin-film solar cell module 14 is light and difficult to break, and thus a highly safe solar cell can be obtained and can be applied to a curved surface, so that it can be used for more applications. Since it is thin and light, it is preferable in terms of distribution such as transportation and storage. Furthermore, since it is in the form of a film, roll-to-roll manufacturing is possible, and a significant cost cut is possible.
Although there is no restriction | limiting in the specific dimension of the organic thin film solar cell module 14, The thickness is usually 300 micrometers or more and 3000 micrometers or less.

<4-12. Manufacturing method>
Although there is no restriction | limiting in the manufacturing method of the organic thin film solar cell module 14 using the organic thin film solar cell element which concerns on this embodiment, For example, as a solar cell manufacturing method of the form of FIG. 3, the laminated body shown by FIG. A method of performing a laminate sealing step after the creation is mentioned. Since the organic thin-film solar cell element according to this embodiment is excellent in heat resistance, it is preferable in that deterioration due to the laminate sealing step is reduced.

  The laminated body shown in FIG. 3 can be produced using a known technique. The method of the laminate sealing step is not particularly limited as long as the effects of the present invention are not impaired, but for example, wet lamination, dry lamination, hot melt lamination, extrusion lamination, coextrusion molding lamination, extrusion coating, photocuring adhesive Laminate, thermal laminate, etc. are mentioned. Among them, a laminating method using a photo-curing adhesive having a proven record in organic EL device sealing, a hot melt laminate or a thermal laminate having a proven record in solar cells is preferable, and a hot melt laminate or a thermal laminate is a sheet-like sealing material. It is more preferable at the point which can be used.

  The heating temperature in the laminate sealing step is usually 130 ° C or higher, preferably 140 ° C or higher, and is usually 180 ° C or lower, preferably 170 ° C or lower. The heating time in the laminate sealing step is usually 10 minutes or longer, preferably 20 minutes or longer, and is usually 100 minutes or shorter, preferably 90 minutes or shorter. The pressure in the laminate sealing step is usually 0.001 MPa or more, preferably 0.01 MPa or more, and usually 0.2 MPa or less, preferably 0.1 MPa or less. By setting the pressure within this range, sealing can be performed reliably, and the reduction of the film thickness due to the protrusion of the sealing materials 5 and 7 from the end portion and overpressurization can be suppressed, thereby ensuring dimensional stability. In addition, what connected two or more organic thin film solar cell elements 6 in series or in parallel can be manufactured similarly to the above.

<4-13. Application>
There is no restriction | limiting in the use of the organic thin film solar cell module 14 using the organic thin film solar cell element which concerns on embodiment of this invention, It can use for arbitrary uses. Examples of fields to which organic thin-film solar cell modules are applied include building material solar cells, automotive solar cells, interior solar cells, railway solar cells, marine solar cells, airplane solar cells, and spacecraft solar cells. , Solar cells for home appliances, solar cells for mobile phones, solar cells for toys, and the like.

The organic thin film solar cell module may be used as it is, or an organic thin film solar cell module may be installed on a substrate and used as an organic thin film solar cell panel. For example, as schematically shown in FIG. 4, an organic thin film solar cell panel 13 provided with an organic thin film solar cell module 14 may be prepared on a substrate 12 and used at a place of use. That is, the organic thin film solar cell panel 13 can be manufactured using the organic thin film solar cell module 14. If a specific example is given and the board | plate material for building materials is used as the base material 12, the organic thin film solar cell panel 13 can be produced by providing the organic thin film solar cell module 14 on the surface of this board | plate material.

  The substrate 12 is a support member that supports the organic thin film solar cell module 14. Examples of the material for forming the substrate 12 include inorganic materials such as glass, sapphire, and titania; polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, polyimide, nylon, polystyrene, polyvinyl alcohol, ethylene vinyl alcohol copolymer, fluorine. Organic materials such as resin, vinyl chloride, polyethylene, cellulose, polyvinylidene chloride, aramid, polyphenylene sulfide, polyurethane, polycarbonate, polyarylate and polynorbornene; paper materials such as paper and synthetic paper; metals such as stainless steel, titanium and aluminum; Examples thereof include composite materials such as those obtained by coating or laminating a surface of a metal such as stainless steel, titanium, and aluminum to impart insulation.

  In addition, 1 type may be used for the material of a base material, and 2 or more types may be used together by arbitrary combinations and a ratio. Moreover, carbon fiber may be included in these organic materials or paper materials to reinforce the mechanical strength. When the example of the base material 12 is given, Alpolic (registered trademark; manufactured by Mitsubishi Plastics) and the like may be mentioned.

  Although there is no restriction | limiting in the shape of the base material 12, Usually, a board | plate material is used. Moreover, what is necessary is just to set the material of the base material 12, a dimension, etc. arbitrarily according to the use environment. This solar cell panel can be installed on the outer wall of a building.

Hereinafter, the present invention will be described in detail by way of examples.
In addition, the measurement of the contact angle of the active layer in an Example was performed according to JIS2396 using the pure water.
Moreover, the evaluation of the adhesion of the hole extraction layer was performed according to JISK5400. After forming 100 squares using a cutter in the hole extraction layer, a peel test using an adhesive tape was performed, and the number of remaining squares was expressed in%.

<Comparative Example 1>
A ZnO nanoparticle dispersion was applied onto a glass substrate on which an ITO electrode was patterned by spin coating, and heat treatment was performed at 150 ° C. for 60 minutes to form an electron extraction layer having a thickness of about 100 nm. In a nitrogen atmosphere, a P3HT / PCBM mixture was applied onto the electron extraction layer with a wire bar, and after confirming that the surface was dry, heat treatment was performed at 150 ° C. for 30 minutes, and the thickness was about 180 nm. Layers were deposited. The contact angle of the active layer was 105 °.
A dispersion of PEDOT: PSS was applied to the active layer by spin coating, and a heat treatment was performed at 120 ° C. for 10 minutes to form a hole extraction layer having a thickness of about 100 nm. As a result of testing the adhesion of the hole extraction layer, the remaining mass was 0%.
The conversion efficiency of the organic thin-film solar cell element obtained by forming a silver film having a thickness of about 100 nm on the hole extraction layer by a vacuum deposition method was 2.75%.

<Comparative example 2>
In Comparative Example 1, an organic thin film solar cell element was similarly produced except that the active layer was subjected to corona treatment. Corona treatment was performed 5 times at a discharge power of 12.7 kW using a corona scanner ASA-4 (manufactured by Shinko Electric Instrumentation Co., Ltd.).
The evaluation results are shown in Table 1.

<Comparative Example 3>
In Comparative Example 2, an organic thin film solar cell element was similarly produced except that the corona treatment was changed to UV treatment. The UV treatment was performed for 2 minutes at a rating using a UV dry processor VUM-3073-F02-00 (manufactured by Oak Manufacturing Co., Ltd.).
The evaluation results are shown in Table 1.

<Example 1>
In Comparative Example 2, an organic thin film solar cell element was similarly produced except that the corona treatment was a remote atmospheric pressure plasma treatment. The remote atmospheric pressure plasma treatment uses AP / T03-H550Z (manufactured by Sekisui Chemical Co., Ltd.) in a clean room (22 ° C., 45% RH) in a nitrogen atmosphere with an oxygen concentration of 1000 ppm, using an electrode distance of 3 mm and a voltage of 410 V. At a frequency of 30 kHz.
The evaluation results are shown in Table 1.

<Example 2>
In Example 1, the same method was used except that remote atmospheric pressure plasma treatment was performed in a dry room (22 ° C., dew point −30 ° C.), the electrode distance was 5 mm, the frequency was 10 kHz, and the oxygen concentration in nitrogen was 300 ppm. A thin film solar cell element was prepared.
The evaluation results are shown in Table 1.

From Table 1, it can be seen that in Comparative Example 1 where the treatment of the active layer is not performed, the contact angle is large, so that the coating property is poor when a film is formed on the active layer by coating. Moreover, since the adhesiveness of an active layer and a hole taking-out layer is bad, it turns out that it peels easily when force, such as a physical impact, is added to a solar cell element.
On the other hand, Comparative Examples 2, 3 and Examples in which the treatment of the active layer was performed showed good coating properties of the hole extraction layer, which is also indicated by a small contact angle. Further, it can be seen that Comparative Examples 2, 3 and Examples have high adhesion between the active layer and the hole extraction layer and are difficult to peel off due to physical force. However, compared to Comparative Examples 2 and 3 subjected to corona treatment and UV treatment, Examples 1 and 2 subjected to the remote atmospheric pressure plasma treatment of the present invention have very little reduction in conversion efficiency due to surface treatment.
As mentioned above, according to this invention, in manufacturing an organic thin film solar cell, the applicability | paintability of an organic layer can be improved and the manufacturing method of the organic thin film solar cell which is hard to produce the defect of a solar cell can be provided.

Reference Signs List 30 Frame 31 Gas inlet 32 Reaction tube 33 Plasma generated 34 Plasma outlet 35 Electrode 37 Organic layer 40 Remote atmospheric pressure plasma processing apparatus 101 Lower electrode 102 Electron extraction layer 103 Active layer 104 Hole extraction layer 105 Upper electrode 106 Solar cell element substrate 107 Organic thin film solar cell element 1 Weather-resistant protective film 2 UV cut film 3, 9 Gas barrier film 4, 8 Getter material film 5, 7 Sealing material 6 Organic thin film solar cell element 10 Back sheet 12 Base material 13 Organic Thin film solar cell panel 14 Organic thin film solar cell module

Claims (5)

A method for producing an organic thin film solar cell having at least a pair of electrodes and an organic layer on a substrate,
A manufacturing method including a processing step of performing remote atmospheric pressure plasma processing on the organic layer.   2. The manufacturing method according to claim 1, wherein a processing gas used for remote atmospheric pressure plasma processing in the processing step has an oxygen concentration of 3000 ppm or less.   The manufacturing method according to claim 1, wherein the treatment step is performed in a dry room.   The said dry room is a manufacturing method of Claim 3 which is an atmosphere with a dew point of -10 degrees C or less.   The manufacturing method of any one of Claim 1 to 4 which is a roll-to-roll form.

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