JP2023017360A - Method for manufacturing organic thin film solar cell and organic thin film solar cell - Google Patents

Abstract

To provide a method for manufacturing an organic thin-film solar cell using bonding.SOLUTION: A method for manufacturing an organic thin film solar cell comprises: a first laminating process of preparing a first laminate 10 in which a first electrode 2 and an organic active layer 3 are laminated in sequence on a substrate 1; a second laminating process of preparing a second laminate 20 in which a second electrode 7 is laminated on a coating layer 8; and a bonding process of bonding the organic active layer 3 of the first laminate 10 and the second electrode 7 of the second laminate 20 by thermocompression bonding.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing an organic thin-film solar cell and an organic thin-film solar cell.

Organic thin-film solar cells are attracting attention because there are few restrictions on where they can be installed and it is relatively easy to increase the size of the device.

An organic thin-film solar cell is obtained by sequentially stacking a first electrode, an organic active layer, and a second electrode. Each layer of the organic thin film solar cell is formed by, for example, a dry process such as a vacuum deposition method, a sputtering method, an ion plating method, or a chemical vapor deposition method, or a wet process such as coating using a dispersion.

For example, Patent Literature 1 describes a method of manufacturing the second electrode by a wet process.

JP 2014-236064 A

Organic active layers in organic thin-film solar cells are susceptible to damage by heat and solvents. For example, when an electrode is vapor-deposited on an organic active layer, the organic active layer is damaged by heat during vapor deposition. Further, for example, when an electrode is applied on the organic active layer by a wet process, the organic active layer is damaged by the solvent contained in the coating liquid.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for manufacturing an organic thin film solar cell using bonding.

In order to solve the above problems, the present invention provides the following means.

(1) A method for manufacturing an organic thin film solar cell according to the first aspect includes a first lamination step of preparing a first laminate in which a first electrode and an organic active layer are laminated in order on a substrate; A second lamination step of preparing a second laminate in which a second electrode is laminated, and bonding the organic active layer of the first laminate and the second electrode of the second laminate by thermocompression bonding, and a bonding step.

(2) In the method for manufacturing an organic thin-film solar cell according to the aspect described above, the coating layer may be a hot-melt sheet having a melting point or glass transition point lower than that of the organic active layer.

(3) In the method for manufacturing an organic thin film solar cell according to the aspect described above, the thickness of the second electrode may be 20 nm or more and 150 nm or less.

(4) In the method for manufacturing an organic thin-film solar cell according to the aspect described above, the thermocompression temperature may be lower than the melting point or glass transition point of the organic active layer and higher than the melting point or glass transition point of the coating layer. .

(5) In the method for manufacturing an organic thin-film solar cell according to the aspect described above, the thermocompression bonding pressure may be 80 g/cm ² or more and 650 g/cm ² or less.

(6) The method for manufacturing an organic thin-film solar cell according to the aspect described above further includes the step of modifying the surface of the second electrode with a modifier having a sulfide group, a disulfide group, or a thiol group before the bonding step. may

(7) An organic thin-film solar cell according to a second aspect includes a first electrode, an organic active layer, a second electrode, and a coating layer in this order, and a first electrode on the coating layer side of the second electrode. The surface has a glossiness of 30 or more and 35 or less when measured at an incident angle of 60° as defined in JIS Z 8741.

(8) In the organic thin film solar cell according to the above aspect, the second surface of the second electrode facing the first surface has a glossiness of 60 or more and 65 when measured at an incident angle of 60° specified in JIS Z 8741. It may be below.

(9) In the organic thin film solar cell according to the aspect described above, the second surface of the second electrode opposite to the first surface may be modified with a modifier having a sulfide group, a disulfide group, or a thiol group. .

(10) In the organic thin film solar cell according to the aspect described above, the surface of the first electrode on the organic active layer side may be modified with a modifier having a silyl ether group, a carboxylic acid group, or a phosphonic acid group.

The method for manufacturing an organic thin film solar cell according to this embodiment can reduce damage to the organic active layer.

1 is a perspective view of an organic thin film solar cell according to a first embodiment; FIG. It is a perspective view for demonstrating the 1st lamination process of the manufacturing method of the organic thin-film solar cell which concerns on 1st Embodiment. It is a perspective view for demonstrating the 2nd lamination process of the manufacturing method of the organic thin-film solar cell which concerns on 1st Embodiment. It is a perspective view for demonstrating the bonding process of the manufacturing method of the organic thin-film solar cell which concerns on 1st Embodiment. It is the perspective view of the organic thin-film solar cell which concerns on 2nd Embodiment, and the enlarged view of a characteristic part. It is the perspective view of the organic thin-film solar cell which concerns on 3rd Embodiment, and the enlarged view of a characteristic part. 1 shows current-voltage curves (JV curves) of organic thin film solar cells of Example 1, Example 2 and Comparative Example 1. FIG. 1 shows the irradiation time change of the energy conversion efficiency of the organic thin film solar cells of Examples 1, 3 and 4. FIG. 1 shows the irradiation time change of the energy conversion efficiency of the organic thin film solar cells of Examples 1, 5 and 6. FIG. 1 shows the irradiation time change of the energy conversion efficiency of the organic thin film solar cells of Examples 1, 7 and 8. FIG. 10 shows a current-voltage curve (JV curve) of the organic thin film solar cell of Example 9. FIG. FIG. 10 shows the irradiation time change of the energy conversion efficiency of the organic thin film solar cell of Example 9. FIG. 2 shows current-voltage curves (JV curves) of organic thin film solar cells of Examples 9 and 10. FIG.

The present embodiment will be described in detail below. The following description is an example of the present invention, and the present invention is not limited to them, and can be implemented with appropriate modifications without changing the gist of the invention.

"First Embodiment"
FIG. 1 is a perspective view of an organic thin film solar cell according to the first embodiment. The organic thin-film solar cell 1000 comprises, for example, a substrate 1, a first electrode 2, an organic active layer 3, a second electrode 7 and a covering layer 8. A first electrode 2 , an organic active layer 3 , a second electrode 7 and a coating layer 8 are laminated in this order on the substrate 1 .

The substrate 1 is not particularly limited as long as it supports a structure. It is preferable that the substrate 1 has excellent light transmittance. The substrate 1 has, for example, a visible light transmittance of 90% or more. Also, the substrate 1 is preferably flexible. The substrate 1 is, for example, glass, plastic film, or the like. As a resin constituting the plastic film, for example, polyethylene terephthalate, polyethylene naphthalate, etc. can be used.

The first electrode 2 is, for example, a transparent electrode. A first electrode 2 is on the substrate 1 . A known electrode can be applied to the first electrode 2 . The first electrode 2 is, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide, tin oxide, titanium oxide, graphene, or the like.

The organic active layer 3 is a layer containing an organic semiconductor. The organic active layer 3 is sandwiched between the first electrode 2 and the second electrode 7 . The organic active layer 3 has an electron collection layer 4, a power generation layer 5, and a hole collection layer 6, for example. The electron collection layer 4 and the hole collection layer 6 sandwich the power generation layer 5 . The electron collection layer 4 is, for example, on the first electrode 2 side of the power generation layer 5 . The hole collection layer 6 is located, for example, on the second electrode 7 side of the power generation layer 5 . The positional relationship between the electron collection layer 4 and the hole collection layer 6 may be reversed depending on the energy levels of the first electrode 2 and the second electrode 7 . For example, when the second electrode 7 is gold, the relationship shown in FIG. 1 is satisfied, but when the second electrode 7 is aluminum, the positional relationship between the electron collection layer 4 and the hole collection layer 6 is reversed. . The electron-collecting layer 4 is sometimes called an electron-transporting layer, and the hole-collecting layer 6 is sometimes called a hole-transporting layer.

The power generation layer 5 is a layer that receives light and generates power. The power generation layer 5 contains donors and acceptors. The power generation layer 5 may be a layer (bulk heterostructure) in which a donor and an acceptor are mixed, or may be a layer in which a donor layer and an acceptor layer are laminated (laminated structure). The donor absorbs light and becomes excited. Excited excitons migrate to the donor-acceptor interface. When an exciton gives an electron to an acceptor, the donor produces a cation (hole) and the acceptor produces an anion. Current flows in an external circuit as cations and anions flow toward different electrodes.

The donor is, for example, a p-type organic semiconductor. A known donor can be used. Donors are, for example, conjugated polymers, phthalocyanine derivatives, porphyrin derivatives, triarylamine derivatives, carbazole derivatives, oligothiophene derivatives and the like. For example, poly(3-hexylthiophene-2,5-diyl) (P3HT) is a conjugated polymer and is used as a donor.

The acceptor is, for example, an n-type organic semiconductor. A known acceptor can be used, and may be a non-fullerene compound or a fullerene compound. Acceptors of fullerene compounds are, for example, [60]PCBM, bis-[60]PCBM, [70]PCBM, bis-[70]PCBM and the like. In addition, fullerene derivatives having a silylmethyl group (SIMEF) and the like are also examples of acceptors of fullerene compounds. Acceptors of non-fullerene compounds include, for example, TTBT compounds, ITIC compounds, IDT compounds, IDTT compounds, TTCTT compounds, and PPhTQ.

The electron collection layer 4 is a layer that collects electrons in order to efficiently transport the electrons generated in the power generation layer 5 toward the first electrode 2 . A well-known thing can be used for the electron collection layer 4. FIG. The electron collection layer 4 is, for example, metal oxide or metal nitride. The oxides used for the electron collection layer 4 include, for example, titanium oxide, zinc oxide, silicon oxide, tin oxide, tungsten oxide, tantalum oxide, barium titanate, barium zirconate, zirconium oxide, hafnium oxide, aluminum oxide, oxide yttrium and zirconium silicate. The nitride used for the electron collection layer 4 is, for example, silicon nitride. In addition, the electron collection layer 4 can use, for example, cadmium sulfide, zinc selenide, zinc sulfide, cadmium telluride, and the like.

The hole collection layer 6 is a layer that collects holes in order to efficiently transport electrons generated in the power generation layer 5 toward the second electrode 7 . A known material can be used for the hole collecting layer 6 . The hole-collecting layer 6 is, for example, PEDOT:PSS (composite of poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS)).

The second electrode 7 is a material having conductivity. A second electrode 7 is on the organic active layer 3 . The second electrode 7 is, for example, a metal such as gold, silver or aluminum, or an organic conductive ink such as PEDOT:PSS.

When the second electrode 7 is metal, the second surface 7B of the second electrode 7 is more glossy than the first surface 7A. The configuration is derived from the manufacturing method to be described later. The first surface 7A is the surface of the second electrode 7 on the coating layer 8 side, and the second surface 7B is the surface of the second electrode 7 on the organic active layer 3 side.

The second surface 7B is a glossy surface. The second surface 7B has gloss mainly due to the exposure of the (111) surface. “Mainly the (111) plane is exposed” means that 50% or more of the second plane 7B is (111) oriented when the crystal plane is measured at 10 different arbitrary measurement points. do. The glossiness of the second surface 7B is 60 or more and 65 or less. Glossiness is a value measured at an incident angle of 60° in accordance with JIS Z 8741. Glossiness can be measured, for example, with a gloss meter (GC-1, UGV-6P) manufactured by Suga Test Instruments Co., Ltd., or the like.

The first surface 7A is a non-glossy surface and looks duller than the second surface 7B. In the first surface 7A, mainly the (111) plane is not exposed. The glossiness of the first surface 7A is 30 or more and 35 or less.

The thickness of the second electrode 7 is, for example, 20 nm or more and 150 nm or less. The thickness of the second electrode 7 is preferably 100 nm or less, more preferably 30 nm or more and 60 nm or less. When the thickness of the second electrode 7 is sufficiently thin, followability of the second electrode 7 to the organic active layer 3 is enhanced in the bonding process described later.

A covering layer 8 is on the second electrode 7 . The coating layer 8 prevents moisture and the like from entering the organic active layer 3 and prevents contamination of the organic active layer 3 .

The coating layer 8 is a resin sheet. The coating layer 8 is, for example, fluororesin or polyester-based resin (eg, PET). The coating layer 8 is, for example, a hot-melt sheet having a lower melting point or glass transition point than the organic active layer 3 (especially the power generation layer 5). In the later-described bonding step, the cover layer 8 is melted by thermocompression bonding, so that the followability of the second electrode 7 to the organic active layer 3 is enhanced.

The coating layer 8 preferably has a Rockwell hardness (D-785) of R115 or less. Since the coating layer 8 is sufficiently soft, the conformability of the coating layer 8 and the second electrode 7 to the organic active layer 3 is enhanced.

The thickness of the coating layer 8 is, for example, 100 μm or less, preferably 50 μm or less. The thickness is the thickness after thermocompression bonding. When the coating layer 8 has sufficient flexibility, the conformability of the second electrode 7 to the organic active layer 3 is enhanced.

Next, a method for manufacturing the organic thin film solar cell 100 according to the first embodiment will be described. The method for manufacturing the organic thin-film solar cell 100 according to the first embodiment includes a first stacking step, a second stacking step, and a bonding step.

FIG. 2 is a schematic diagram for explaining the first lamination step. In the first stacking step, the first stack 10 is prepared. The first laminate 10 is produced by laminating the first electrode 2 and the organic active layer 3 on the substrate 1 in this order. The first electrode 2 can be formed by, for example, vacuum deposition. The organic active layer 3 can be formed, for example, by coating. The 1st electrode 2 and the organic active layer 3 can be produced by a well-known method.

FIG. 3 is a schematic diagram for explaining the second lamination step. In the second stacking step, the second stack 20 is prepared. The second laminate 20 is formed by depositing the second electrode 7 on the coating layer 8 . The second electrode 7 can be produced by vacuum deposition or coating, for example. For example, the second electrode 7 can be produced by vacuum-depositing gold on the coating layer 8 . Further, for example, a silver paste diluted with 1,2-dimethoxyethane is applied on the coating layer 8 and baked to form the second electrode 7 .

When the second electrode 7 is deposited on the covering layer 8, the second surface 7B of the second electrode 7 is exposed. The second electrode 7 grows so that the (111) plane is exposed, and the second surface 7B becomes a glossy surface.

FIG. 4 is a schematic diagram for explaining the bonding process. In the bonding step, the first laminate 10 and the second laminate 20 are attached. The first laminate 10 and the second laminate 20 are attached so that the organic active layer 3 of the first laminate 10 and the second electrode 7 of the second laminate 20 face each other. Bonding is performed by thermocompression bonding.

Thermocompression bonding is performed, for example, at a temperature lower than the melting point or glass transition point of the organic active layer 3 (especially the power generation layer 5). Also, the thermocompression bonding is preferably performed at a temperature higher than the melting point or glass transition point of the coating layer 8 . For example, the thermocompression bonding temperature is preferably 130° C. or higher and 180° C. or lower, more preferably 140° C. or higher and 150° C. or lower. By performing thermocompression bonding in this temperature range, it is possible to ensure the adhesion between the first laminate 10 and the second laminate 20 and to suppress damage to the organic active layer 3 .

The pressure for thermocompression bonding is, for example, 80 g/cm ² or more and 650 g/cm ² or less. The pressure of thermocompression bonding is more preferably 80 g/cm ² or more and 325 g/cm ² or less, for example. If the pressure is too high, the performance of the organic thin-film solar cell 100 tends to deteriorate. If the pressure is too low, the conformability of the second electrode 7 to the organic active layer 3 will deteriorate.

The thermocompression bonding time is, for example, 1 minute or longer. The crimping time is preferably 3 minutes or more and 10 minutes or less, more preferably 4 minutes or more and 6 minutes or less. If the crimping time is short, the performance of the organic thin film solar cell 100 tends to deteriorate, and if the crimping time is long, the stability of the organic thin film solar cell 100 tends to deteriorate.

By thermocompression bonding, the second electrode 7 adheres to the surface of the organic active layer 3, and the organic thin-film solar cell 100 is obtained.

Since the organic thin-film solar cell 100 according to the first embodiment does not form the second electrode 7 on the organic active layer 3, damage to the organic active layer 3 can be reduced. Moreover, the organic thin film solar cell 100 according to the first embodiment can be produced by a simple method of bonding.

"Second Embodiment"
FIG. 5 is a perspective view of an organic thin-film solar cell 101 according to the second embodiment and an enlarged view of a characteristic portion. The organic thin film solar cell 101 according to the second embodiment differs from the organic thin film solar cell 100 according to the first embodiment in that the second surface 7B of the second electrode 7 is modified with a modifier. In the organic thin film solar cell 101 according to the second embodiment, the same components as those of the organic thin film solar cell 100 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

A second surface 7B of the second electrode 7 is modified with a modifying material. The modifier has a sulfide group, a disulfide group or a thiol group. The modifier has a binding site at one end and a functional site at the other end. Sulfide groups, disulfide groups or thiol groups serve as binding sites. The binding sites chemisorb, for example, to the surface of the second electrode 7 to form a self-assembled monolayer. When the second electrode 7 is gold and the second surface 7B is the (111) surface, a particularly homogeneous self-assembled monolayer is formed. The modifier is, for example, pentafluorobenzenethiol (PFBT).

The organic thin film solar cell 101 according to the second embodiment is manufactured in the same manner as the organic thin film solar cell 100 according to the first embodiment, except that the surface of the second electrode 7 is modified before the bonding process. be able to. The method for manufacturing the organic thin film solar cell 101 according to the second embodiment further includes a step of surface-modifying the second electrode 7 with a modifying agent having a sulfide group, a disulfide group, or a thiol group before the bonding step.

The second surface 7B of the second electrode 7 is surface-modified after laminating the second laminate 20 and before the bonding step. When the second electrode 7 is vacuum deposited on the organic active layer 3, the surface cannot be coated with a modifier. The surface modification is performed by, for example, applying a solution containing a modification material to the second surface 7B of the second electrode 7 . For example, the solvent of the solution is ethanol.

After that, in a bonding step, the second electrode 7 and the organic active layer 3 are bonded together. The functional portion of the modifier exposed on the second surface 7B of the second electrode 7 is bonded to the organic active layer 3 . For example, pentafluorobenzenethiol (PFBT) has the effect of promoting hole injection.

Since the organic thin film solar cell 101 according to the second embodiment does not form the second electrode 7 on the organic active layer 3, damage to the organic active layer 3 can be reduced. Moreover, the organic thin film solar cell 101 according to the second embodiment can be produced by a simple method of bonding. Further, by surface-modifying the second surface 7B of the second electrode 7, the short-circuit current density and energy conversion efficiency (PCE) of the organic thin-film solar cell 101 are improved.

"Third Embodiment"
FIG. 6 is a perspective view of an organic thin-film solar cell 102 according to the third embodiment and an enlarged view of a characteristic portion. The organic thin film solar cell 102 according to the third embodiment differs from the organic thin film solar cell 101 according to the second embodiment in that the first surface 2A of the first electrode 2 is modified with a modifier. In the organic thin film solar cell 102 according to the third embodiment, the same components as those of the organic thin film solar cell 101 according to the second embodiment are denoted by the same reference numerals, and description thereof is omitted.

The first surface 2A of the first electrode 2 is modified with a modifier. The first surface 2A is the surface of the first electrode 2 on the organic active layer 3 side. The second surface 2B is the surface of the first electrode 2 on the substrate 1 side.

A modifier that modifies the first surface 2A has a silyl ether group, a carboxylic acid group, or a phosphonic acid group. The modifier has a binding site at one end and a functional site at the other end. Silyl ether groups, carboxylic acid groups or phosphonic acid groups serve as binding sites. When the binding site binds to the first electrode 2, the modifier becomes a self-assembled monolayer. For example, when the first electrode 2 is ITO, the titanium element of the first electrode 2 and the functional site of the modifier are bonded. Modifiers are, for example, polyethyleneimine (PEIE), triphenyl(4-sulfonatobutyl)phosphonium (TPPBS).

The organic thin film solar cell 102 according to the third embodiment is the same as the organic thin film solar cell 101 according to the second embodiment, except that the surface of the first electrode 2 is modified before forming the organic active layer 3. method. In the method for manufacturing the organic thin film solar cell 102 according to the third embodiment, the surface of the first electrode 2 is modified with a modifier having a silyl ether group, a carboxylic acid group, or a phosphonic acid group before the organic active layer 3 is formed. further comprising the step of The surface modification is performed by, for example, applying a solution containing a modification material to the first surface 2A of the first electrode 2 .

Since the organic thin film solar cell 102 according to the third embodiment does not form the second electrode 7 on the organic active layer 3, damage to the organic active layer 3 can be reduced. Moreover, the organic thin film solar cell 102 according to the third embodiment can be produced by a simple method of bonding. Further, by surface-modifying the first surface 2A of the first electrode 2, the short-circuit current density and energy conversion efficiency (PCE) of the organic thin-film solar cell 102 are improved.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to specific embodiments, and various can be transformed or changed.

(Example 1)
First, the first laminate 10 was produced. The first laminate 10 was produced by laminating an electron collection layer 4, a power generation layer 5, and a hole collection layer 6 in this order on a substrate 1 on which a commercially available first electrode 2 was formed. Glass was used for the substrate 1 . ITO was used for the first electrode 2 . Zinc oxide was used for the electron collection layer 4 . The power generation layer 5 uses poly(3-hexylthiophene-2,5-diyl) (P3HT) as a donor and [60]PCBM as an acceptor. The power generation layer 5 is a bulk heterostructure.

Next, a second laminate 20 was produced. The second laminate 20 was produced by laminating the second electrode 7 on the coating layer 8 . Cerel (registered trademark) F1550H (manufactured by Kureha Extron Co., Ltd.) was used for the coating layer 8 . The second electrode 7 was deposited with gold at 5×10 ⁻³ Pa. The film thickness of the second electrode 7 was set to 60 nm.

Next, the first laminated body 10 and the second laminated body 20 were thermocompression bonded at 150°C. The crimping time was 5 minutes and the pressure was 325/cm ² . By bonding the first laminate 10 and the second laminate 20 together, an organic thin-film solar cell 100 was produced. The area of the light receiving surface of the organic thin film solar cell 100 was set to 0.1 cm ² .

A current-voltage curve (JV curve) of the produced organic thin film solar cell 100 was measured. A current-voltage curve was measured using a 4262 multi-meter manufactured by ADC Co., Ltd. The measurement results are shown in FIG.

Also, the energy conversion efficiency (PCE) was obtained from the current-voltage curve. The energy conversion efficiency of Example 1 was 2.6%. PCE is obtained from the following equation, where J _max is the current density at the maximum output point, V _max is the voltage, and P _inc is the energy of the irradiated light.
PCE (%)=( _Jmax * _Vmax )/ _Pinc *100

(Example 2)
Example 2 differs from Example 1 in that the second electrode 7 is made of silver by coating. In Example 2, a silver paste diluted with 1,2-dimethoxyethane was applied onto the coating layer 8 and baked at 80° C. for 2 minutes to prepare the second electrode 7 .

Also for Example 2, a current-voltage curve was determined in the same manner as in Example 1, and the energy conversion efficiency (PCE) was determined. The measurement results are shown in FIG. The energy conversion efficiency of Example 1 was 2.5%.

(Comparative example 1)
Comparative Example 1 differs from Example 1 in that the first electrode 2, the electron collection layer 4, the power generation layer 5, the hole collection layer 6, the second electrode 7, and the coating layer 8 are laminated in this order on the substrate 1. different from The material of each layer was the same as in Example 1. For the second electrode 7, a film of gold was formed on the hole collection layer 6 by vacuum deposition.

Also for Comparative Example 1, the current-voltage curve was obtained in the same manner as in Example 1, and the energy conversion efficiency (PCE) was obtained. The measurement results are shown in FIG. The energy conversion efficiency of Comparative Example 1 was 3.0%.

The organic thin-film solar cells of Examples 1 and 2 produced by lamination showed performance equivalent to that of Comparative Example 1 produced by sequentially forming films. That is, even with the simple method of bonding, the same performance as in the case of sequential film formation was exhibited.

(Examples 3 and 4)
Examples 3 and 4 differ from Example 1 in that the film thickness of the second electrode 7 is changed. In Example 3, the film thickness of the second electrode 7 was set to 30 nm. In Example 4, the film thickness of the second electrode 7 was set to 120 nm.

Then, changes over time in the energy conversion efficiency of the organic thin film solar cells of Examples 1, 3 and 4 were measured. The change in energy conversion efficiency with time is the change in energy conversion efficiency with time when the organic thin-film solar cell is continuously irradiated with light in the standard state (AM1.5 all-sky radiation spectrum, 100 mWcm ⁻² ). The results are shown in FIG.

Example 4, in which the film thickness of the second electrode 7 was thick, tended to lower the energy conversion efficiency as compared with Examples 1 and 3. This is probably because the thick second electrode 7 did not sufficiently follow the surface of the organic active layer 3 in the bonding process, resulting in insufficient adhesion.

(Examples 5 and 6)
Examples 5 and 6 differ from Example 1 in that the pressure bonding time in the bonding process was changed. In Example 5, the crimping time was 3 minutes. In Example 6, the crimping time was 10 minutes.

Then, in the same manner as described above, changes over time in the energy conversion efficiency of the organic thin-film solar cells of Examples 1, 5 and 6 were measured. The results are shown in FIG.

Compared with Example 1, Example 5, in which the crimping time was short, tended to lower the energy conversion efficiency. It is considered that this is because the adhesion between the second electrode 7 and the organic active layer 3 was insufficient in the bonding process. Also, in Example 6, in which the crimping time was long, the decrease in energy conversion efficiency was faster than in Example 1.

(Examples 7 and 8)
Examples 7 and 8 differ from Example 1 in that the pressing pressure in the bonding process was changed. In Example 7, the compression pressure was 80/cm ² . In Example 8, the compression pressure was 650/cm ² .

Then, in the same manner as described above, changes over time in the energy conversion efficiency of the organic thin film solar cells of Examples 1, 7 and 8 were measured. The results are shown in FIG.

In Example 7, even when compared with Example 1, the initial energy conversion efficiency was high and the rate of decrease in energy conversion efficiency was small. On the other hand, in Example 8, which has a large crimping pressure, the change in energy conversion efficiency over time was large.

(Example 9)
Example 9 differs from Example 1 in that the area of the light-receiving surface of the organic thin-film solar cell is 1.0 cm ² , which is 10 times that of Example 1.

Also in Example 9, the current-voltage curve and the time change of the energy conversion efficiency were measured in the same manner as described above. The current-voltage curve of Example 9 is shown in FIG. 12, showing the change in the energy conversion efficiency of Example 9 over time. The time change of the energy conversion efficiency of Example 9 was measured over 100 hours. The energy conversion efficiency of Example 9 was 2.3%, which was equivalent to that of Example 1. The energy conversion efficiency after 100 hours in Example 9 was 98% of the maximum value, and the energy conversion efficiency was maintained.

(Example 10)
Example 10 differs from Example 9 in that the second surface 7B of the second electrode 7 is surface-modified. The surface modification was performed by applying ethanol containing pentafluorobenzenethiol to the surface of the second electrode 7 and leaving it for 5 minutes.

Also in Example 10, the current-voltage curve and energy conversion efficiency were measured in the same manner as above. The current-voltage curve and energy conversion efficiency of Example 10 are shown in FIG. The energy conversion efficiency of Example 10 was 2.5%, which was improved compared to Example 9 in which the second surface 7B was not surface-modified. By modifying the electrodes, the short-circuit current density was improved, and as a result, the energy conversion efficiency was improved.

DESCRIPTION OF SYMBOLS 1... Substrate, 2... 1st electrode, 3... Organic active layer, 4... Electron collection layer, 5... Electric power generation layer, 6... Hole collection layer, 7... Second electrode, 8... Coating layer, 10... Second 1 laminate 20 second laminate 2A, 7A first surface 2B, 7B second surface 100, 101, 102 organic thin film solar cell

Claims (10)

a first lamination step of preparing a first laminate in which a first electrode and an organic active layer are sequentially laminated on a substrate;
a second lamination step of preparing a second laminate in which the second electrode is laminated on the covering layer;
a bonding step of bonding the organic active layer of the first laminate and the second electrode of the second laminate by thermocompression bonding. 2. The method of manufacturing an organic thin-film solar cell according to claim 1, wherein said coating layer is a hot-melt sheet having a lower melting point or glass transition point than said organic active layer. 3. The method for manufacturing an organic thin-film solar cell according to claim 1, wherein the thickness of said second electrode is 20 nm or more and 150 nm or less. The organic thin film solar cell according to any one of claims 1 to 3, wherein the thermocompression temperature is lower than the melting point or glass transition point of the organic active layer and higher than the melting point or glass transition point of the coating layer. Production method. The method for producing an organic thin film solar cell according to any one of claims 1 to 4, wherein the pressure of said thermocompression bonding is 80 g/cm ² or more and 650 g/cm ² or less. The organic thin film according to any one of claims 1 to 5, further comprising a step of modifying the surface of the second electrode with a modifier having a sulfide group, a disulfide group, or a thiol group before the bonding step. A method for manufacturing a solar cell. sequentially comprising a first electrode, an organic active layer, a second electrode, and a coating layer;
The organic thin-film solar cell, wherein the first surface of the second electrode on the coating layer side has a glossiness of 30 or more and 35 or less when measured at an incident angle of 60° as defined in JIS Z 8741. 8. The organic thin film solar according to claim 7, wherein the second surface of the second electrode facing the first surface has a glossiness of 60 or more and 65 or less when measured at an incident angle of 60 ° specified in JIS Z 8741. battery. 9. The organic thin-film solar cell according to claim 7, wherein a second surface of said second electrode opposite to said first surface is modified with a modifier having a sulfide group, disulfide group or thiol group. The organic thin film according to any one of claims 7 to 9, wherein the surface of the first electrode on the side of the organic active layer is modified with a modifier having a silyl ether group, a carboxylic acid group, or a phosphonic acid group. solar cell.

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