JP6814329B2 - Lateral carrier collection type organic solar cell - Google Patents

Description

The present invention relates to an organic solar cell, and more particularly to an organic solar cell having a novel structure capable of collecting carriers in the lateral direction.

In recent years, as environmental and energy problems have become more serious on a global scale, the development of solar cells using sunlight, which is environmentally friendly and can continuously supply inexhaustible and clean energy, is being actively studied. Solar cells are roughly classified into non-silicon-based inorganic solar cells using silicon-based or gallium, and dye-sensitized type or organic thin-film type organic solar cells. Among them, expectations are rising for organic solar cells, which have low power generation costs.

As an example of a conventional organic solar cell, an organic solar cell having a vertical bulk heterojunction structure is known. In such a bulk heterojunction structure, an n-type organic semiconductor material (acceptor) and a p-type organic semiconductor material (donor) existing in a photoelectric conversion layer provided between electrode pairs facing each other are complicated at the nano level. It is a three-dimensionally joined structure. When the excitons in the photoelectric conversion layer excited by the photon energy of the incident light reach the pn junction interface, the excitons are separated into holes and electrons, and the holes are transported to one electrode through the donor region, and the acceptor. Electrons are transported through the region to the other electrode. However, the conventional bulk heterojunction layer is a polycrystalline thin film or an amorphous thin film of about 1 μm, and has a large number of grain boundaries, which hinders high-speed separation of holes and electrons by excitons, and as a result. , There was a drawback that carrier transportation loss occurred. Therefore, it is desired to develop an organic solar cell having a new structure capable of overcoming such a drawback.

Patent Document 1 discloses an upright superlattice cell in which a superlattice in which p-type organic semiconductor layers and n-type organic semiconductor layers are alternately and vertically laminated is sandwiched between two metal electrodes. Further, also in Patent Document 2, a vertical superlattice structure provided with photoelectric conversion layers in which p-type organic polymer layers and n-type organic polymer layers are alternately and vertically laminated between electrode pairs facing each other. The organic thin film solar cell having the above is disclosed. However, in order to manufacture such an upright type and vertical type superlattice structure, a laminated body in which p-type organic semiconductor layers and n-type organic semiconductor layers are alternately laminated is once produced, and then the superlattice is produced. It is necessary to vertically cut the laminate with a very thin width of several μm to several hundred nm in thickness in order to obtain the above. As a result, a superlattice having a very thin thickness can be obtained, but the manufacturing process is complicated, and the p-type organic semiconductor layer and the n-type organic semiconductor layer having a very thin thickness are alternately arranged vertically. It was also difficult to control the laminated structure because of the lamination.

In Patent Document 3, by optimally combining an electron donor and an electron acceptor, a hole nanotransport path is formed in the electron donor portion and an electron nanotransport path is formed in the electron acceptor portion, and holes and electrons are efficiently transferred to their respective electrodes. A bulk heterojunction organic solar cell that can be injected well is disclosed, in which case porphyrin, which is an electron donor, and fullerene, which is an electron acceptor, are alternately laminated as an ideal schematic diagram of the bulk heterojunction type organic solar cell. A structure in which the side surfaces of the laminated body are sandwiched between ITO electrodes and aluminum electrodes facing each other is disclosed. However, since sunlight is incident from the ITO side of the positive electrode, the moving direction of holes and electrons and the incident direction of sunlight are the same in such an organic solar cell. Therefore, Patent Document 3 only discloses a structure similar to that of a conventional vertical bulk heterojunction type organic solar cell, and the above-mentioned drawbacks still exist.

Japanese Unexamined Patent Publication No. 2004-103939 International Publication No. 2012/172878 Japanese Unexamined Patent Publication No. 2005-236278

In conventional vertical bulk heterojunction type organic solar cells and organic solar cells having a vertical superlattice structure, even if a material having high carrier mobility is used as the material of the organic semiconductor layer, each electrode collects carriers. The limit of the possible distance is that the distance between the electrodes is about 1 μm. Therefore, when the carrier transport distance, that is, the film thickness of the organic semiconductor layer is increased, the distance between the electrodes is correspondingly increased, and as a result, it is impossible to transport the carrier to the corresponding electrode. Further, if the total thickness of the layer existing between the electrodes is increased, the distance between the electrodes is also increased, so that the carriers cannot be collected on the corresponding electrodes. Therefore, there is a limit to the thickness of the layer that can be provided between the electrodes, and it is difficult to further laminate a material that can impart new characteristics between the electrodes.

In view of the above circumstances, an object of the present invention is to provide a novel organic solar cell capable of transporting carriers to the corresponding electrodes even if the distance between the electrodes is relatively long, and further thickening the layer between the electrodes. To provide.

As a result of diligent studies to solve the above problems, the present inventors have found a substrate on which sunlight is incident and a pair of electrodes formed on the same surface side of the substrate at a predetermined distance. The organic semiconductor layer comprises at least one p-type organic semiconductor layer made of a hole-transportable donor material and at least one n-type organic semiconductor layer made of an electron-transportable acceptor material. By using an organic solar cell having a novel structure of the lateral collection type, which is characterized in that one or both of them can transport carriers in the lateral direction of the organic semiconductor layer, the distance between the electrodes can be reduced. We have newly found that carriers can be transported to a corresponding electrode even if they are relatively long, for example, 10 μm or more, and have reached the present invention.

（式（１）中、
Ｘ^１及びＸ^２は、互いに独立して、カルコゲン原子であり、
Ｒ¹乃至Ｒ^８は、互いに独立して、水素原子、ハロゲン原子、アルキル基、アルケニル基、アルキニル基、アリール基、アルキルオキシ基又はアルキルチオ基であり、
Ｒ^２及びＲ^３並びにＲ^６及びＲ^７は、それらが結合するベンゼン環と一緒になって、非置換の又は１以上の置換基を有するナフタレン、アントラセン又はフェナントレンの環を形成してもよく、前記置換基は、互いに独立して、水素原子、ハロゲン原子、アルキル基、アルケニル基、アルキニル基、アリール基、アルキルオキシ基又はアルキルチオ基である）で表される化合物であるか、又は
下記式（５）

（式（５）中、
Ｒ^ｃ及びＲ^ｄは、互いに独立して、水素原子、置換基を有してもよいアリール基、又は置換基を有してもよいアルキル基であり、かつＲ^ｃ、Ｒ^ｄが複数ある場合は、それぞれ同じであっても、異なっていてもよく、
ｍ及びｎは、互いに独立して、１〜４の整数である）で表される化合物であることを特徴とする（１）、（２）、（３）、（５）又は（６）に記載の有機太陽電池。
（８）前記ドナー材料が、下記式（２）

（式（２）中、
Ｘ^１及びＸ^２は、互いに独立して、硫黄原子、セレン原子又はテルル原子であり、かつ
Ｒ^ａ及びＲ^ｂは、互いに独立して、水素原子、アルキル基又はフェニル基である）で表される化合物であるか；
下記式（３）

（式（３）中、
Ｘ^１及びＸ^２は、互いに独立して、硫黄原子、セレン原子又はテルル原子であり、かつ
Ｒ^９乃至Ｒ^２０は、互いに独立して、水素原子、アルキル基又はフェニル基である）で表される化合物であるか；又は、
下記式（４）

（式（４）中、
Ｘ^１及びＸ^２は、互いに独立して、硫黄原子、セレン原子又はテルル原子であり、かつ
Ｒ^２１乃至Ｒ^３６は、互いに独立して、水素原子、アルキル基又はフェニル基である）で表される化合物であることを特徴とする（７）に記載の有機太陽電池。
（９）前記ドナー材料が、前記式（２）で表される化合物であり、
Ｘ^１及びＸ^２は、それぞれ硫黄原子であり、かつＲ^ａ及びＲ^ｂは、それぞれアルキル基であることを特徴とする（８）に記載の有機太陽電池。
（１０）前記アクセプター材料が、Ｎ，Ｎ’−ジオクチル−３，４，９，１０−ペリレンジカルボキシミド又はＮ，Ｎ０−１Ｈ，１Ｈ−ペルフルオロブチル−シアノペリレンジイミドであることを特徴とする（１）、（２）、（４）、（５）又は（６）に記載の有機太陽電池。
（１１）前記所定の距離は１０μｍ以上であることを特徴とする、（１）乃至（１０）のいずれか１つに記載の有機太陽電池。 That is, the gist structure of the present invention is as follows.
(1) The substrate on which sunlight is incident and
On the same surface side of the substrate,
A pair of electrodes formed at a predetermined distance,
Both organic semiconductor layers, at least one p-type organic semiconductor layer made of a hole-transportable donor material and at least one n-type organic semiconductor layer made of an electron-transportable acceptor material,
With
A lateral carrier collecting type organic solar cell, characterized in that one or both of the organic semiconductor layers has a property of transporting holes or electron carriers in the lateral direction of the organic semiconductor layer.
(2) The p-type organic semiconductor layer and one of the n-type organic semiconductor layers formed on the surface of the substrate and the organic semiconductor layer.
A pair of electrodes formed on the surface side of the one organic semiconductor layer directly or via an intermediate layer at a predetermined distance.
One electrode of the pair of electrodes and the other organic semiconductor layer formed between the one organic semiconductor layer.
With
The organic solar cell according to (1), wherein the carrier mobility to be transported in the lateral direction of the one organic semiconductor layer is 0.01 cm ² / V · s or more.
(3) The one organic semiconductor layer is a p-type organic semiconductor layer, and the other organic semiconductor layer is an n-type organic semiconductor layer.
One electrode is a second electrode that collects electrons, the other electrode is a first electrode that collects holes, and the acceptor material in the n-type organic semiconductor layer is a fullerene derivative. , (2).
(4) The one organic semiconductor layer is an n-type organic semiconductor layer, and the other organic semiconductor layer is a p-type organic semiconductor layer.
The one electrode is the first electrode that collects holes, the other electrode is the second electrode that collects electrons, and the donor material in the p-type organic semiconductor layer is a dibenzotetraphenylperifrantene or a phthalocyanine derivative. The organic solar cell according to (2), characterized in that.
(5) An organic semiconductor layer of both the p-type organic semiconductor layer and the n-type organic semiconductor layer formed on the surface of the substrate.
A pair of electrodes formed on the surface side of each organic semiconductor layer, either directly or via an intermediate layer at a predetermined distance,
One or more laminated units formed between the electrodes of the pair of electrodes and composed of both of the organic semiconductor layers, and
With
The organic solar cell according to (1), wherein the carrier mobility to be transported in the lateral direction of both of the organic semiconductor layers is 0.01 cm ² / V · s or more.
(6) Of the pair of electrodes, the electrode formed on the surface side of the p-type organic semiconductor layer is the first electrode that collects holes, and the electrode formed on the surface side of the n-type organic semiconductor layer. The organic solar cell according to (5), wherein is a second electrode that collects electrons.
(7) The donor material in the p-type organic semiconductor layer is
The following formula (1)

(In equation (1),
X ¹ and X ² are chalcogen atoms, independent of each other.
R ^{1 to} R ⁸ are independent of each other and are a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkyloxy group or an alkylthio group.
R ² and R ³ and R ⁶ and R ⁷ may be combined with the benzene ring to which they are attached to form an unsubstituted or naphthalene, anthracene or phenanthrene ring having one or more substituents. The substituent is a compound represented by a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkyloxy group or an alkylthio group independently of each other, or the following formula ( 5)

(In equation (5),
When R ^c and R ^d are independent of each other, a hydrogen atom, an aryl group which may have a substituent, or an alkyl group which may have a substituent, and there are a plurality of R ^c and R ^d. Can be the same or different,
In (1), (2), (3), (5) or (6), m and n are compounds represented by (1), (2), (3), (5) or (6) independently of each other. The organic solar cell described.
(8) The donor material is the following formula (2).

(In equation (2),
X ¹ and X ² are independently represented by a sulfur atom, a selenium atom or a tellurium atom, and ^Ra and R ^b are independently represented by a hydrogen atom, an alkyl group or a phenyl group). Is it a compound?
The following formula (3)

(In equation (3),
X ¹ and X ² are independent of each other as a sulfur atom, a selenium atom or a tellurium atom, and R ^{9 to} R ²⁰ are independent of each other as a hydrogen atom, an alkyl group or a phenyl group). Is it a compound?
The following formula (4)

(In equation (4),
X ¹ and X ² are independently represented by a sulfur atom, a selenium atom or a tellurium atom, and R ^{21 to} R ³⁶ are independently represented by a hydrogen atom, an alkyl group or a phenyl group). The organic solar cell according to (7), which is a compound.
(9) The donor material is a compound represented by the formula (2).
The organic solar cell according to (8), wherein X ¹ and X ² are sulfur atoms, respectively, and ^Ra and R ^b are alkyl groups, respectively.
(10) The acceptor material is N, N'-dioctyl-3,4,9,10-perylene carboxymid or N, N0-1H, 1H-perfluorobutyl-cyanoperylene imide (10). The organic solar cell according to 1), (2), (4), (5) or (6).
(11) The organic solar cell according to any one of (1) to (10), wherein the predetermined distance is 10 μm or more.

The organic solar cell of the present invention has a characteristic that one or both of an organic semiconductor layer composed of a p-type organic semiconductor layer and an organic semiconductor layer composed of an n-type organic semiconductor layer can transport carriers in the lateral direction of the organic semiconductor layer. Therefore, even if the distance between the electrodes, that is, the carrier transport distance in the organic semiconductor layer is, for example, a relatively long 10 μm or more, the carriers can be transported to the corresponding electrodes. In addition, the structure in which carriers can be transported in the lateral direction of the organic semiconductor layer makes it possible to thicken the layer, which is limited in vertical organic solar cells. Therefore, the material to be laminated can be further selected, and as a result, an organic solar cell that can utilize the characteristics of the material to be laminated can be obtained. For example, all of the sunlight utilizing the absorption characteristics peculiar to each material. It can be expected that absorption in the wavelength basin will be possible. Further, since each electrode can be arranged at a relatively long distance, each electrode can be arranged by a simple process such as mask deposition without performing a complicated process such as microfabrication.

It is the schematic sectional drawing which shows the 1st Embodiment of the organic solar cell according to this invention. It is a schematic sectional drawing which shows the 2nd Embodiment of the organic solar cell which follows this invention. It is the schematic sectional drawing which shows the 3rd Embodiment of the organic solar cell according to this invention. It is a schematic sectional drawing which shows the 4th Embodiment of the organic solar cell which follows this invention. It is the schematic sectional drawing which shows the 5th Embodiment of the organic solar cell according to this invention.

Hereinafter, a typical organic solar cell according to the present invention will be described below with reference to the drawings. It should be noted that the embodiments shown below merely illustrate typical embodiments used to specifically explain the present invention, and various embodiments can be taken within the scope of the present invention.

The organic solar cell of the present invention comprises at least one p consisting of a substrate on which sunlight is incident, a pair of electrodes formed on the surface side of the substrate at a predetermined distance, and a hole-transportable donor material. It comprises both an organic semiconductor layer of a type organic semiconductor layer and at least one n-type organic semiconductor layer made of an electron-transportable acceptor material, and one or both of the organic semiconductor layers is the organic semiconductor layer. It is a lateral carrier collecting type organic solar cell having a property of being able to transport carriers in the lateral direction (hereinafter, simply referred to as “lateral direction”). Therefore, the organic solar cell of the present invention is a conventional vertical type having a property of transporting carriers in the thickness direction (hereinafter, referred to as "vertical direction") of both the p-type organic semiconductor layer and the n-type organic semiconductor layer. It has different characteristics from the heterojunction type and bulk heterojunction type organic solar cells.

FIG. 1 is an example of a configuration diagram of a lateral carrier collecting type organic solar cell that transports carriers in the lateral direction in both the p-type organic semiconductor layer and the n-type organic semiconductor layer. In such a configuration, electrode pairs facing each other are formed on the substrate 1 at a predetermined distance, and the p-type organic semiconductor layer 2 and the n-type organic semiconductor layer 3 are laminated between these electrodes. One of the electrode pairs is the first electrode 4 that collects holes, and the other is the second electrode 5 that collects electrons. The p-type organic semiconductor layer 2 made of a hole-transportable donor material means a hole-transporting layer, and the n-type organic semiconductor layer 3 made of an electron-transportable acceptor material means an electron-transporting layer. Thereby, a lateral carrier collecting type organic solar cell in which carriers are transported in the lateral direction in both the p-type organic semiconductor layer 2 and the n-type organic semiconductor layer 3 can be manufactured. It is also possible to stack a plurality of units of the p-type organic semiconductor layer 2 and the n-type organic semiconductor layer 3 to further improve the power generation efficiency.

In the organic solar cell of the present invention, one or both of the donor material constituting the p-type organic semiconductor layer and the acceptor material constituting the n-type organic semiconductor layer are carriers of 0.01 cm ² / V · s or more in the lateral direction. It is preferable to have the mobility (hereinafter, referred to as “carrier mobility”). Here, the donor material means an organic semiconductor material having an electron donating property, that is, a hole transporting material, and the acceptor material means an organic semiconductor material having an electron acceptor property, that is, an electron transporting material. By using either or both of the donor material and the acceptor material having high carrier mobility, the carriers are arranged laterally even when the distance between the electrodes is relatively long. It can be transported to the corresponding electrode, and as a result, a lateral carrier collection type organic solar cell can be obtained. The higher the carrier mobility, the more preferable, more preferably 0.1 cm ² / V · s or more, and further preferably 1.0 cm ² / V · s or more.

により求めることができる。式中、μはキャリア移動度（ｃｍ^２／Ｖ・ｓ）を表し、τはキャリア寿命（ｍｓ）を表し、Ｅは内蔵電界（Ｖ／ｃｍ）を表す。例えば、使用するドナー材料のμ_ｈが１．１×１０^−２ｃｍ^２／Ｖ・ｓ、ドナー材料のτ_ｈが３．８ｍｓ（３．８×１０^−３ｓ）、内蔵電界が１２０Ｖ／ｃｍであった場合、キャリア飛程は、Ｌ_ｈ＝約５．０×１０^−３ｃｍ＝約５０μｍとなる。したがって、キャリア移動度が高いほどキャリア飛程も長くなり、その結果、電極間距離Ｌもより長くすることが可能となる。 In order for the donor and acceptor materials to transport carriers to the corresponding electrodes, they must have sufficient carrier range for lateral carrier transport. The carrier range corresponds to the distance L between the electrodes, and the following formula

Can be obtained by. In the equation, μ represents carrier mobility (cm ² / V · s), τ represents carrier lifetime (ms), and E represents built-in electric field (V / cm). For example, the donor material used has a μ _h of 1.1 × 10 ⁻² cm ² / V · s, the donor material τ _h is 3.8 ms (3.8 × 10 ^-3 s), and the built-in electric field is 120 V / cm. If, the carrier range is L _h = about 5.0 × 10 ^-3 cm = about 50 μm. Therefore, the higher the carrier mobility, the longer the carrier range, and as a result, the distance L between the electrodes can be made longer.

Donor and acceptor materials with high carrier mobility have a longer carrier range, based on the above formula. Therefore, even if the distance between the electrodes is 10 μm or more, the carrier can be transported in the lateral direction, and it is also possible to manufacture an organic solar cell having a distance between the electrodes of 30 μm or more, more preferably 50 μm or more. Is. Even if the distance between the electrodes is relatively long, the organic solar cell of the present invention exhibits a short-circuit current value J _sc equivalent to that of the conventional vertical organic solar cell in the effective cell area, and can function as an organic solar cell. It was unexpected.

The above-mentioned "effective cell area" means a region in which holes and electrons are effectively separated at a bonding surface between the p-type organic semiconductor layer and the n-type organic semiconductor layer used in the present invention. As will be described later, in the present invention, of the p-type organic semiconductor layer and the n-type organic semiconductor layer, one of the organic semiconductor layers transports holes laterally from the bonding surface, and the other organic semiconductor layer transports holes from the bonding surface. A mode of transporting electrons in the vertical direction is included. As described above, when the transport mode of the carriers in each organic semiconductor layer is different, the holes and the electrons are separated not in the entire joint surface but in a part of the joint surface. For example, when the joint surface is a square having a length of 2 mm and a width of 2 mm, the area of the entire joint surface is 0.04 cm ² . When the region where the holes and electrons are separated is in the range of 2 mm in length and 0.018 mm in width in the entire joint surface, the effective cell area is 2 mm × 0.018 mm = 0.0036 cm ² . The organic solar cell in the present invention has a short-circuit current value J _sc equivalent to that of the conventional vertical organic solar cell when the short-circuit current value J _sc of the conventional vertical organic solar cell is converted for each effective cell area. Shown.

In one embodiment of the present invention, one of the p-type organic semiconductor layer and the n-type organic semiconductor layer has the property of being able to transport carriers in the lateral direction. FIG. 2 is an example of a configuration diagram of a single-layer lateral carrier collecting type organic solar cell in which carriers are transported in the horizontal direction in the p-type organic semiconductor layer and carriers are transported in the vertical direction in the n-type organic semiconductor layer. is there. A p-type organic semiconductor layer 2 is formed on the substrate 1, and a first electrode 4 for collecting holes is arranged on a part of the surface side of the p-type organic semiconductor layer 2. Further, the n-type organic semiconductor layer 3 is directly laminated on the p-type organic semiconductor layer 2 at a position laterally separated from the first electrode 4 by a distance L, and electrons are collected on the n-type organic semiconductor layer 3. The second electrode 5 of the above is arranged. Sunlight is incident from the substrate 1, sunlight is applied to the junction surface 6 between the p-type organic semiconductor layer 2 and the n-type organic semiconductor layer 3, and the obtained excitons are separated into holes and electrons. Next, the p-type organic semiconductor layer 2 transports holes in the lateral direction from the bonding surface 6, and the transported holes are collected in the first electrode 4, while the n-type organic semiconductor layer 3 transports holes in the longitudinal direction from the bonding surface 6. The electrons are transported to the second electrode 5, and the transported electrons are collected in the second electrode 5. The distance L corresponds to the distance between the electrodes, and the donor material constituting the p-type organic semiconductor layer 2 has carrier mobility of 0.01 cm ² / V · s or more so that holes can move this distance L. Materials with degrees (hole mobility) are used. On the other hand, for the n-type organic semiconductor layer 3, a material capable of transporting electrons in the vertical direction is used. As such a material, a fullerene derivative is preferably used. Here, the fullerene derivative is not particularly limited as long as it has a fullerene skeleton, and examples thereof include derivatives having C60, C70, C76, C78, C84 and the like as the basic skeleton, and are preferable. C60 fullerenes are used. Further, as shown in FIG. 3, in order to further increase the transport efficiency of carriers, between the p-type organic semiconductor layer 2 and the first electrode 4, and between the n-type organic semiconductor layer 3 and the second electrode 5. Can also be inserted through the intermediate layers 7 and 8, respectively.

FIG. 4 is an example of a configuration diagram of a single-layer lateral carrier collecting type organic solar cell in which carriers are transported in the horizontal direction in the n-type organic semiconductor layer and carriers are transported in the vertical direction in the p-type organic semiconductor layer. is there. An n-type organic semiconductor layer 3 is formed on the substrate 1, and a second electrode 5 for collecting electrons is arranged on a part of the surface side of the n-type organic semiconductor layer 3. Further, the p-type organic semiconductor layer 2 is directly laminated on the n-type organic semiconductor layer 3 at a position laterally separated from the second electrode 5 by a distance L, and holes are collected on the p-type organic semiconductor layer 3. The first electrode 4 of the above is arranged. Sunlight is incident from the substrate 1, sunlight is applied to the junction surface 6 between the n-type organic semiconductor layer 3 and the p-type organic semiconductor layer 2, and the obtained excitons are separated into holes and electrons. Next, the n-type organic semiconductor layer 3 transports electrons laterally from the bonding surface 6, and the transported electrons are collected by the second electrode 5, while the p-type organic semiconductor layer 2 transports electrons vertically from the bonding surface 6. The holes are transported to the first electrode 4, and the transported holes are collected in the first electrode 4. The distance L corresponds to the distance between the electrodes, and the n-type organic semiconductor layer 3 has carrier mobility (electron mobility) of 0.01 cm ² / V · s or more so that electrons can move this distance L. ) Is used. On the other hand, for the p-type organic semiconductor layer 2, a material capable of transporting holes in the vertical direction is used. As such a material, dibenzotetraphenylperifrantene (DBP) or a phthalocyanine derivative is preferably used. Here, the phthalocyanine derivative is not particularly limited as long as it is a derivative having a phthalocyanine skeleton, and examples thereof include copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), H2 phthalocyanine (H2Pc), and the like, preferably H2. Phthalocyanine is used. Further, in order to further increase the transport efficiency of the carrier, an intermediate layer is interposed between the p-type organic semiconductor layer 2 and the first electrode 4 and between the n-type organic semiconductor layer 3 and the second electrode 5, respectively. You can also do it.

In one embodiment of the present invention, both the p-type organic semiconductor layer and the n-type organic semiconductor layer have the property of being able to transport carriers in the lateral direction. FIG. 5 is an example of a configuration diagram of a lateral carrier collecting type organic solar cell in a stack in which carriers are transported in the lateral direction in both the p-type organic semiconductor layer and the n-type organic semiconductor layer. A laminated unit of the p-type organic semiconductor layer 2 and the n-type organic semiconductor layer 3 is formed on the substrate 1, and the type organic semiconductor layer 3 is further directly laminated on the surface of the p-type organic semiconductor layer 2. Is formed in. A first electrode 4 for collecting holes is arranged on a part of the surface of the p-type organic semiconductor layer 2, and similarly, a second electrode 4 for collecting electrons is arranged on a part of the surface of the n-type organic semiconductor layer 3. The electrode 5 is arranged. Sunlight is incident from the substrate 1, sunlight is applied to the junction surface 6 between the n-type organic semiconductor layer 3 and the p-type organic semiconductor layer 2, and the obtained excitons are separated into holes and electrons. Next, the p-type organic semiconductor layer 2 transports holes laterally from the bonding surface 6, the transported holes are collected by the first electrode 4, and the n-type organic semiconductor layer 3 is similarly laterally transported from the bonding surface 6. The transported electrons are collected in the second electrode 5 via the n-type organic semiconductor layer 3. The distance L corresponds to the distance between the electrodes, and 0.01 cm ² / V · s is provided to both the p-type organic semiconductor layer 2 and the n-type organic semiconductor layer 3 so that carriers can move this distance L. A material having the above carrier mobility is used. Further, in order to further improve the transport efficiency of the carrier, an intermediate layer is interposed between the p-type organic semiconductor layer 2 and the first electrode 4 and between the n-type organic semiconductor layer 3 and the second electrode 5, respectively. You can also. Further, it is also possible to manufacture a lateral carrier collecting type organic solar cell having a configuration in which a plurality of laminated units of a p-type organic semiconductor layer 2 and an n-type organic semiconductor layer 3 existing between electrodes are laminated.

Next, an example of a material used for producing each layer provided in the organic solar cell of the present invention and a method for producing each layer will be described.

(substrate)
Since the substrate in the present invention is for allowing sunlight to enter, a material having high transmittance is used. On the other hand, since the substrate is not used as an electrode, it is preferably a material having high electrical resistance. The substrate having such characteristics is not particularly limited, but for example, polymer films such as polyimide (PI), polyethylene terephthalate (PET), phenol resin, and epoxy resin, soda lime glass, and lead. Examples thereof include glass materials such as glass, borosilicate glass, and silica glass (quartz glass), and quartz glass is preferably used. The surface of the substrate may be flat or may have irregularities. The thickness of the substrate is usually in the range of 0.05 mm to 3 mm, preferably in the range of 0.1 mm to 1 mm, and more preferably in the range of 0.3 nm to 0.8 mm.

(electrode)
The pair of electrodes in the present invention are arranged so that carriers can be collected from the corresponding organic semiconductor layer. Of the pair of electrodes, one acts as an anode because it collects holes, and the other acts as a cathode because it collects electrons. The materials of these electrodes are not particularly limited as long as they have conductivity, and may be the same or different from each other. However, when a pair of electrodes are formed on the surface side of the organic semiconductor layer, it is desirable that these electrodes are made of a material having low transparency to sunlight. Examples of materials for such electrodes include aluminum (Al), gold (Au), silver (Ag), cobalt (Co), nickel (Ni), platinum (Pt), copper (Cu), titanium (Ti), and the like. Examples thereof include conductive metals such as aluminum alloys, titanium alloys and nickel-chromium alloys (Ni—Cr). Among them, Al, Au, Ag, Cu and the like having relatively low electric resistance values are preferable, and Ag is particularly preferable. For these electrodes, for example, the material to be used can be formed into a film by a vacuum deposition method, a sputtering method, an ion plating method, a plating method, a coating method, or the like. The film thickness of these electrodes is usually in the range of 1 nm to 500 nm, preferably in the range of 10 nm to 300 nm, and at that time, the film thickness of each electrode may be the same or different.

（式（１）中、
Ｘ^１及びＸ^２は、互いに独立して、カルコゲン原子であり、
Ｒ¹乃至Ｒ^８は、互いに独立して、水素原子、ハロゲン原子、アルキル基、アルケニル基、アルキニル基、アリール基、アルキルオキシ基又はアルキルチオ基であり、
Ｒ^２及びＲ^３並びにＲ^６及びＲ^７は、それらが結合するベンゼン環と一緒になって、非置換の又は１以上の置換基を有するナフタレン、アントラセン又はフェナントレンの環を形成してもよく、前記置換基は、互いに独立して、水素原子、ハロゲン原子、アルキル基、アルケニル基、アルキニル基、アリール基、アルキルオキシ基又はアルキルチオ基である）で表される化合物が挙げられる。 (P-type organic semiconductor layer)
In the present invention, in order to impart the property that the p-type organic semiconductor layer can transport holes in the lateral direction, a donor material having a relatively high carrier mobility (hole mobility) is used, preferably 0 in the lateral direction. Donor materials with hole mobility of .01 cm ² / V · s or higher are used. Examples of such donor materials include the following formula (1).

(In equation (1),
X ¹ and X ² are chalcogen atoms, independent of each other.
R ^{1 to} R ⁸ are independent of each other and are a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkyloxy group or an alkylthio group.
R ² and R ³ and R ⁶ and R ⁷ may be combined with the benzene ring to which they are attached to form an unsubstituted or naphthalene, anthracene or phenanthrene ring having one or more substituents. Examples of the substituent include compounds represented by hydrogen atom, halogen atom, alkyl group, alkenyl group, alkynyl group, aryl group, alkyloxy group or alkylthio group independently of each other.

In the above formula (1), the "chalcogen atom" means an oxygen atom, a sulfur atom, a selenium atom or a tellurium atom.

Further, in the above formula (1), examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

Further, in the above formula (1), the alkyl group may be linear or branched, and may be, for example, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group or a heptyl group. , Octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecil group, icosyl group, henicosyl group, docosyl group, tricosyl group Group, pentacosyl group, hexacosyl group, heptacosyl group, octacosyl group, nonacosyl group, triacontyl group, hentoriacontyl group, dotriacyl group, tritoriacontyl group, tetratriacontyl group, pentatriacontyl group, hexatriacontyl group However, the present invention is not limited to these.

Further, in the above formula (1), the alkenyl group may be linear or branched, and for example, an ethenyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group and an octenyl group. , Nonenyl group, decenyl group, undecenyl group, dodecenyl group, icosenyl group, triacenyl group and the like, but are not limited thereto.

Further, in the above formula (1), the alkynyl group may be linear or branched, and for example, an ethynyl group, a propynyl group, a butynyl group, a pentynyl group, a hexynyl group, a heptynyl group and an octynyl group. , Noninyl group, decynyl group, undecynyl group, dodecynyl group, icosinyl group, triacynyl group and the like, but are not limited thereto.

Further, in the above formula (1), the aryl group is, for example, a phenyl group, a naphthyl group, an anthranyl group, a frill group, a thienyl group, a selenofryl group, a thienotienyl group and the like, but is not limited thereto.

Further, in the above formula (1), the alkyloxy group may be linear or branched, and may be, for example, a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group or the like. , Not limited to these.

Further, in the above (1), the alkylthio group may be either linear or branched, and may be, for example, a methylthio group, an ethylthio group, a propylthio group, a butylthio group, a pentylthio group or the like. It is not limited.

（式（２）中、
Ｘ^１及びＸ^２は、上記式（１）に定義された通りであり、好ましくは、互いに独立して、硫黄原子、セレン原子又はテルル原子であり、かつ
Ｒ^ａ及びＲ^ｂは、上記式（１）のＲ¹乃至Ｒ^８に定義された通りであり、好ましくは、互いに独立して、水素原子、アルキル基又はフェニル基である）で表される化合物；
下記式（３）

（式（３）中、
Ｘ^１及びＸ^２は、上記式（１）に定義された通りであり、好ましくは、互いに独立して、硫黄原子、セレン原子又はテルル原子であり、かつ
Ｒ^９乃至Ｒ^２０は、上記式（１）のＲ¹乃至Ｒ^８に定義された通りであり、好ましくは、互いに独立して、水素原子、アルキル基又はフェニル基である）で表される化合物；又は、
下記式（４）

（式（４）中、
Ｘ^１及びＸ^２は、上記式（１）に定義された通りであり、好ましくは、互いに独立して、硫黄原子、セレン原子又はテルル原子であり、かつ
Ｒ^２１乃至Ｒ^３６は、上記式（１）のＲ¹乃至Ｒ^８に定義された通りであり、好ましくは、互いに独立して、水素原子、アルキル基又はフェニル基である）で表される化合物が好ましい。 Among the compounds represented by the above formula (1), the following formula (2)

(In equation (2),
X ¹ and X ² are as defined in the above formula (1), preferably independent of each other, a sulfur atom, a selenium atom or a tellurium atom, and ^Ra and R ^b are the above formula ( A compound represented by (1) as defined in R ^{1 to} R ⁸ and preferably a hydrogen atom, an alkyl group or a phenyl group independently of each other;
The following formula (3)

(In equation (3),
X ¹ and X ² are as defined in the above formula (1), preferably independent of each other, a sulfur atom, a selenium atom or a tellurium atom, and R ^{9 to} R ²⁰ are the above formula ( is as defined for R ¹ to R ⁸ in 1), preferably, independently of one another, a hydrogen atom, a compound represented by the alkyl group or phenyl group); or
The following formula (4)

(In equation (4),
X ¹ and X ² are as defined in the above formula (1), preferably independent of each other, a sulfur atom, a selenium atom or a tellurium atom, and R ^{21 to} R ³⁶ are the above formula ( Compounds represented by (1) as defined in R ^{1 to} R ⁸ and preferably independent of each other and represented by a hydrogen atom, an alkyl group or a phenyl group) are preferable.

（式（５）中、
Ｒ^ｃ及びＲ^ｄは、互いに独立して、水素原子、置換基を有してもよいアリール基、又は置換基を有してもよいアルキル基であり、かつＲ^ｃ、Ｒ^ｄが複数ある場合は、それぞれ同じであっても、異なっていてもよく、
ｍ及びｎは、互いに独立して、１〜４の整数である）で表される化合物も挙げられる。 Examples of the donor material include the following formula (5).

(In equation (5),
When R ^c and R ^d are independent of each other, a hydrogen atom, an aryl group which may have a substituent, or an alkyl group which may have a substituent, and there are a plurality of R ^c and R ^d. Can be the same or different,
Independent of each other, m and n are integers of 1 to 4).

In the above formula (5), examples of the aryl group include aromatic hydrocarbon groups such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, a pyrenyl group and a benzopyrenyl group; a pyridyl group, a pyrazil group, a pyrimidyl group and a quinolyl group. , Isoquinolyl group, pyrrolyl group, indolenyl group, imidazolyl group, carbazolyl group, thienyl group, furyl group, pyranyl group, pyridonyl group and other heterocyclic groups; benzoquinolyl group, anthraquinolyl group, benzothienyl group, benzofuryl group Examples include heterocyclic groups. Of these, a phenyl group, a naphthyl group, a pyridyl group or a thienyl group is preferable, and a phenyl group is particularly preferable.

Further, in the above formula (5), examples of the alkyl group include saturated or unsaturated linear, branched or cyclic alkyl groups, and the number of carbon atoms thereof is preferably 1 to 20. Here, examples of saturated or unsaturated linear or branched alkyl groups include, for example, a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, and an iso-butyl group. , Allyl group, t-butyl group, n-pentyl group, n-hexyl group, n-octyl group, n-decyl group, n-dodecyl group, n-stearyl group, n-butenyl group and the like. Examples of the cyclic alkyl group include cycloalkyl groups having 3 to 12 carbon atoms such as cyclohexyl group, cyclopentyl group, adamantyl group and norbornyl group. Of these, preferably a linear alkyl group of saturated, lower alkyl group of C ₁ -C ₃ are particularly preferred.

Further, in the above formula (5), examples of substituents that the aryl group and the alkyl group may have and the number thereof are not particularly limited, but examples of the substituent include an aryl group, a halogen atom and an alkyl. The group etc. can be mentioned. The aryl group and the alkyl group as the substituent may be the same as the aryl group and the alkyl group defined above, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Among these substituents, lower alkyl groups C _{1 to} C ₃ are particularly preferable.

Since a material having a higher hole mobility is used as the donor material in the present invention, the compound represented by the above formula (2) is preferable, and in the formula (2), X ¹ and X ² are sulfur atoms, respectively. It is more preferable that R ^a and R ^b are compounds having an alkyl group, respectively, and ^Ra and R ^b are particularly preferably n-octyl groups, respectively. Such a compound is 2,7-dioctyl [1] benzothiophene [3,2-b] [1] benzothiophene, also commonly known as C8-BTBT. C8-BTBT has a very high carrier mobility of 0.3 to 40 cm ² / V · s and is suitable for hole transportation over a relatively long distance.

The film thickness of the p-type organic semiconductor layer is usually in the range of 1 nm to 500 nm, preferably in the range of 5 nm to 200 nm, and more preferably in the range of 20 nm to 150 nm. The p-type organic semiconductor layer is not particularly limited as long as it can form a film. For example, a dry film deposition method such as a vacuum deposition method, a sputtering method, a plasma, or an ion plating method, or a spin coating method. , A wet film forming method such as an inkjet method can also be applied. Further, a plurality of p-type organic semiconductor layers may be alternately laminated with n-type organic semiconductor layers, and at that time, each layer of the p-type organic semiconductor layer may be the same material or a different material from each other. , The film thickness may be the same or different.

(N-type organic semiconductor layer)
In the present invention, an acceptor material having a relatively high carrier mobility (electron mobility) is used in order to impart the property that the n-type organic semiconductor layer can transport electrons in the lateral direction, preferably 0 in the lateral direction. An acceptor material with electron mobility of .01 cm ² / V · s or higher is used. Examples of such acceptor materials include N, N'-dioctyl-3,4,9,10-perylene carboxymid or N, N0-1H, 1H-perfluorobutyl-cyanoperylene diimide. When an organic single crystal is used as the acceptor material, a single crystal of 1,4,5,8-naphthalenetetracarboxylicdianehydride (NTCDA) can also be used.

Since a material having higher electron mobility is used as the acceptor material in the present invention, it is preferable to use N, N'-dioctyl-3,4,9,10-perylene carboxymid, commonly known as PTCDI-C8. be called. PTCDI-C8 has a very high carrier mobility of 0.6 to 1.7 cm ² / V · s and is suitable for electron transport over relatively long distances.

The film thickness of the n-type organic semiconductor layer is usually in the range of 1 nm to 500 nm, preferably in the range of 5 nm to 200 nm, and more preferably in the range of 20 nm to 150 nm. Further, the n-type organic semiconductor layer is not particularly limited as long as it is a method capable of forming a film like the p-type organic semiconductor layer. For example, a vacuum deposition method, a sputtering method, a plasma, an ion plating method and the like can be used. Wet film forming methods such as a dry film forming method, a spin coating method, and an inkjet method can also be applied. Further, a plurality of n-type organic semiconductor layers may be alternately laminated with the p-type organic semiconductor layer, and at that time, each layer of the n-type organic semiconductor layer may be the same material or a different material from each other. , The film thickness may be the same or different.

(Middle layer)
In the organic solar cell of the present invention, an intermediate layer may be further laminated between the electrode for collecting holes and the p-type organic semiconductor layer, and the electrode for collecting electrons and the n-type organic semiconductor layer An intermediate layer may be further laminated between the two. By interposing the intermediate layer at the interface between each electrode and the organic semiconductor layer, the contact between each electrode and the organic semiconductor layer can be improved. Examples of the material of the intermediate layer for transporting holes that can be inserted between the electrode that collects holes and the p-type organic semiconductor layer include PEDOT (poly (3,4-ethylenedioxythiophene)) and PSS poly (4-). Examples thereof include a complex composed of styrene sulfonate), MoO ₃ (molybdenum trioxide), and examples of the material of the intermediate layer for electron transport that can be inserted between the electrode for collecting electrons and the n-type organic semiconductor layer. , BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline). These intermediate layers can be formed by a vacuum deposition method, a spin coating method, or the like, and these intermediate layers can be formed. The thickness of each intermediate layer is 1 nm to 100 nm, preferably 5 nm to 70 nm, and when intermediate layers are formed between each electrode and the organic semiconductor layer, the thickness of each intermediate layer is the same but different. You may.

Next, the organic solar cell of the present invention will be described by way of examples, but the present invention is not limited to these examples.

<Creation of cell>
[Example 1] (horizontal collection type cell using C8-BTBT)
C8-BTBT (hole mobility: 0.3 to 0.8 cm ² / V) on a quartz substrate with a thickness of about 0.7 mm using a high vacuum thin-film vapor deposition bell jar (manufactured by ULVAC Kiko Co., Ltd .: VST-350M / ER). -S) was vacuum-deposited to form a hole transport layer (p-type organic semiconductor layer) having a film thickness of 50 nm. Next, a metal mask having an opening of 2 mm × 2 mm was attached onto the C8-BTBT film, and fullerene C60 as an electron transport layer (n-type organic semiconductor layer) was used as an intermediate layer for electron transport in the openings. BCP and Ag as a cathode were vacuum-deposited in this order. The film thickness of the electron transport layer was 50 nm, the film thickness of the intermediate layer for electron transport was 10 nm, and the film thickness of the cathode was 100 nm. After that, a similar metal mask was attached onto the C8-BTBT film so that the distance between the electrodes from the cathode to the anode was 50 μm, and MoO ₃ as an intermediate layer for hole transportation and MoO _{3 as} an anode were attached to the opening. Vacuum deposition was performed in the order of Ag. The film thickness of the intermediate layer for hole transportation was 10 nm, and the film thickness of the anode was 100 nm. When organic semiconductors are exposed to the atmosphere, they are easily affected by oxygen and moisture in the atmosphere. Therefore, when making the above cells, use the vacuum vapor deposition device built in the glove box to expose the cells to the atmosphere at all. I went without.

<Measurement>
The obtained cell was irradiated with simulated sunlight (100 mW / cm ² ) by a solar simulator (manufactured by Asahi Spectrometer Co., Ltd .: HAL-320) for 30 seconds under vacuum, and the current-voltage characteristics of the cell were measured. The effective cell area of the obtained cell was 0.0036 cm ² because it was in the range of 2 mm in length and 0.018 mm in width in the entire joint surface. The short-circuit current value J _sc per effective cell area of the obtained cell was 0.39 mAcm ^-2 .

<Creation of cell>
[Comparative Example 1] (Vertical standard cell using C8-BTBT)
As an anode, an ITO electrode substrate having a thickness of about 0.7 mm is prepared, and a high vacuum vapor deposition bell jar (manufactured by ULVAC Kiko Co., Ltd .: VST-350M / ER) is used to provide an opening of 2 mm × 2 mm on the ITO electrode substrate. MoO ₃ as an intermediate layer for hole transportation, C8-BTBT as a hole transportation layer (hole mobility: 0.3 to 0.8 cm ² / V · s), Fullerene C60 as an electron transport layer, BCP as an intermediate layer for electron transport, and Ag as a cathode were vacuum-deposited in this order to prepare a vertical standard cell. The film thickness of the intermediate layer for hole transport is 10 nm, the film thickness of the hole transport layer is 50 nm, the film thickness of the electron transport layer is 50 nm, the film thickness of the intermediate layer for electron transport is 10 nm, and the film thickness of the cathode is 100 nm. It was. That is, the obtained standard cell has the same material and film thickness as the cell of the present invention in Example 1, but the carrier transport is not in the horizontal direction but in the vertical direction.

<Measurement>
The obtained standard cell was irradiated with simulated sunlight (100 mW / cm ² ) by a solar simulator (manufactured by Asahi Spectrometer Co., Ltd .: HAL-320) for 30 seconds under vacuum, and the current-voltage characteristics of the standard cell were measured. The short-circuit current value J _sc of the standard cell converted per effective cell area was 0.38 mAcm ^-2 .

<Creation of cell>
[Comparative Example 2] (Horizontal collection type cell using α-NPD)
Horizontally by the same operation as in Example 1 except that α-NPD (hole mobility: 10 ^-4 to 10 ^-3 cm ² / V · s) was used instead of C8-BTBT as the material of the hole transport layer. A direction-collecting cell was prepared.

<Measurement>
The obtained cell was irradiated with simulated sunlight (100 mW / cm ² ) by a solar simulator (manufactured by Asahi Spectrometer Co., Ltd .: HAL-320) for 30 seconds under vacuum, and the current-voltage characteristics of the cell were measured. No short-circuit current value J _sc was observed in the obtained cell.

In Example 1, a short-circuit current value J _sc of 0.39 mAcm- ² per effective cell area was shown between electrodes of 50 μm. From this, it can be seen that the lateral collection type cell of the present invention can transport carriers to the corresponding electrodes even if the distance between the electrodes, that is, the carrier transport distance is relatively long, and can be driven as a solar cell. .. On the other hand, in Comparative Example 1, since the film thickness of the hole transport layer was 50 nm, the short-circuit current value J _sc was 0.38 mAcm- ² per effective cell area at a carrier transport distance of 50 nm. That is, although the carrier transport distance of Comparative Example 1 was about 1/1000 of the carrier transport distance of Example 1, only a short-circuit current value J _sc equivalent to that of Example 1 was obtained. From this, the cell of the present invention in Example 1 has a short-circuit current value J _sc equivalent to that of the conventional vertical standard cell of Comparative Example 1 between electrodes longer than the standard cell and a smaller joint surface. But it can be caused. On the other hand, in the lateral collection type cell of Comparative Example 2, the short-circuit current value J _sc was not observed between the electrodes of 50 μm, which was the same as in Example 1. _Therefore, in the material of the hole transport layer used in Comparative Example 2, p. It can be seen that the characteristic of transporting carriers in the lateral direction of the type organic semiconductor layer is not obtained, and the lateral collection type organic solar cell is not obtained.

The organic solar cell of the present invention can transport carriers to the corresponding electrodes even if the distance between the electrodes is relatively long, and the structure of moving the carriers in the lateral direction of the organic semiconductor layer enables the layer to be thickened. Since the characteristics of the laminated materials can be utilized, for example, it is expected to provide an organic solar cell having new performance capable of absorbing sunlight in all wavelength basins by utilizing the absorption characteristics peculiar to each material. it can.

1 Substrate 2 p-type organic semiconductor layer 3 n-type organic semiconductor layer 4 1st electrode 5 2nd electrode 6 Joint surface 7 Intermediate layer 8 Intermediate layer

Claims (7)

The substrate on which sunlight is incident and
On the same surface side of the substrate,
A pair of electrodes formed at a predetermined distance,
Both organic semiconductor layers, at least one p-type organic semiconductor layer made of a hole-transportable donor material and at least one n-type organic semiconductor layer made of an electron-transportable acceptor material,
With
A lateral carrier collecting type organic solar cell having a property that one or both of the organic semiconductor layers can transport holes or electron carriers in the lateral direction of the organic semiconductor layer .
The organic semiconductor layers of both the p-type organic semiconductor layer and the n-type organic semiconductor layer formed on the surface of the substrate,
A pair of electrodes formed on the surface side of each organic semiconductor layer, either directly or via an intermediate layer at a predetermined distance,
One or more laminated units formed between the electrodes of the pair of electrodes and composed of both of the organic semiconductor layers, and
With
A lateral carrier collecting type organic solar cell characterized in that the mobility of the carriers to be transported in the lateral direction of both of the organic semiconductor layers is 0.01 cm ² / V · s or more . Of the pair of electrodes, the electrode formed on the surface side of the p-type organic semiconductor layer is the first electrode that collects holes, and the electrode formed on the surface side of the n-type organic semiconductor layer collects electrons. The organic solar cell according to claim 1 , wherein the organic solar cell is a second electrode for collecting. The donor material in the p-type organic semiconductor layer is
The following formula (1)

(In equation (1),
X ¹ and X ² are chalcogen atoms, independent of each other.
R ^{1 to} R ⁸ are independent of each other and are a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkyloxy group or an alkylthio group.
R ² and R ³ and R ⁶ and R ⁷ may be combined with the benzene ring to which they are attached to form an unsubstituted or naphthalene, anthracene or phenanthrene ring having one or more substituents. The substituent is a compound represented by a hydrogen atom, a halogen atom, an alkyl group, an alkenyl group, an alkynyl group, an aryl group, an alkyloxy group or an alkylthio group independently of each other, or the following formula ( 5)

(In equation (5),
When R ^c and R ^d are independent of each other, a hydrogen atom, an aryl group which may have a substituent, or an alkyl group which may have a substituent, and there are a plurality of R ^c and R ^d. Can be the same or different,
The organic solar cell according to claim 1 or 2 , wherein m and n are compounds represented by ( 1 to 4) independently of each other. The donor material is the following formula (2)

(In equation (2),
X ¹ and X ² are independently represented by a sulfur atom, a selenium atom or a tellurium atom, and ^Ra and R ^b are independently represented by a hydrogen atom, an alkyl group or a phenyl group). Is it a compound?
The following formula (3)

(In equation (3),
X ¹ and X ² are independent of each other as a sulfur atom, a selenium atom or a tellurium atom, and R ^{9 to} R ²⁰ are independent of each other as a hydrogen atom, an alkyl group or a phenyl group). Is it a compound?
The following formula (4)

(In equation (4),
X ¹ and X ² are independently represented by a sulfur atom, a selenium atom or a tellurium atom, and R ^{21 to} R ³⁶ are independently represented by a hydrogen atom, an alkyl group or a phenyl group). The organic solar cell according to claim 3 , wherein the organic solar cell is a compound. The donor material is a compound represented by the formula (2).
The organic solar cell according to claim 4 , wherein X ¹ and X ² are sulfur atoms, respectively, and ^Ra and R ^b are alkyl groups, respectively. Claim 1 or claim 1, wherein the acceptor material is N, N'-dioctyl-3,4,9,10-perylene carboxymid or N, N0-1H, 1H-perfluorobutyl-cyanoperylene imide. 2. The organic solar cell according to 2. The organic solar cell according to any one of claims 1 to 6 , wherein the predetermined distance is 10 μm or more.

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