WO2012098876A1 - Photoelectric conversion element and method of manufacturing the same, and solar battery - Google Patents

Abstract

The present invention provides a non bulk-heterojunction type photoelectric conversion element, which ensures good adhesion between an electron-donating layer and an electron-accepting layer and allows for the improvement of charge separation efficiency and photoelectric conversion efficiency. The photoelectric conversion element (101) includes between a pair of electrodes (30, 40) with the main surfaces of the respective electrodes being oppositely arranged an electron donating-accepting junction layer (1) in which an electron-donating layer (10) and an electron-accepting layer (20) are jointed, and a mixed layer (1M) having mixed materials of the electron-donating layer (10) and the electron-accepting layer (20) is formed in the electron donating-accepting junction layer (1).

Description

Photoelectric conversion element, method for producing the same, and solar cell

The present invention relates to a photoelectric conversion element including an electron donating / accepting junction layer in which an electron donating layer and an electron accepting layer are joined between a pair of electrodes arranged such that electrode principal surfaces are opposed to each other, and production thereof The present invention relates to a method and a solar cell using the same.

Recently, awareness of environmental issues has been increasing due to global warming, and solar power generation as an alternative to petroleum and photoelectric conversion elements used therefor have attracted attention.
At present, photoelectric conversion elements that are put to practical use for photovoltaic power generation are inorganic semiconductor types typified by crystalline silicon and amorphous silicon. However, these photoelectric conversion elements have enormous energy and cost. For this reason, research and development of photoelectric conversion elements using organic materials that can be manufactured with lower energy and lower costs are being conducted.

Since organic materials are inexpensive and can be manufactured at atmospheric pressure, it is easy to make large areas and continuous processes, so it is thought that photoelectric conversion elements can be manufactured with low energy and low cost. ing.

As an organic photoelectric conversion element, an electron donating layer and an electron accepting layer are formed separately, and a plane-coupled photoelectric conversion element (Example 1 of Patent Document 1) in which these are plane-coupled, and an electron-donating material A bulk hetero-coupled photoelectric conversion element (Example 2 of Patent Document 1) coated with a coating agent in which an electron-accepting material is mixed, and a bulk hetero-evaporated electron-donating material and an electron-accepting material A combined photoelectric conversion element (Patent Document 2, etc.) has been proposed.

JP 2006-245073 A Japanese Patent No. 3369154

The contact state such as the interfacial area and adhesion between the electron donating layer and the electron accepting layer greatly contributes to the charge separation efficiency and greatly affects the performance of the photoelectric conversion element.
In the conventional planar coupling type photoelectric conversion element, the interface area between the electron donating layer and the electron accepting layer cannot be larger than the area of these layers. Further, since the electron donating layer and the electron accepting layer are separately formed and laminated, their adhesion is not good. Therefore, it is difficult to improve the photoelectric conversion efficiency in the conventional planar coupling type photoelectric conversion element.
In conventional bulk heterojunction photoelectric conversion elements, it is difficult to precisely control the phase separation structure between the electron donating material and the electron accepting material, and it is difficult to improve the photoelectric conversion efficiency.

The present invention has been made in view of the above circumstances, and has good adhesion between an electron donating layer and an electron accepting layer, and can improve charge separation efficiency and photoelectric conversion efficiency. An object of the present invention is to provide a conversion element.
The present invention can also increase the interfacial area between the electron donating layer and the electron accepting layer, provide good adhesion between the electron donating layer and the electron accepting layer, and improve the charge separation efficiency and the photoelectric conversion efficiency. An object is to provide a possible non-bulk heterojunction photoelectric conversion element.

The photoelectric conversion element of the present invention is
A photoelectric conversion element comprising an electron donating / accepting junction layer in which an electron donating layer and an electron accepting layer are joined between a pair of electrodes arranged such that electrode principal surfaces face each other,
A mixed layer in which the material of the electron donating layer and the material of the electron accepting layer are mixed is formed in the electron donating / accepting bonding layer.

In the photoelectric conversion element of the present invention,
The electron donating layer includes a cross-sectional stripe-like portion in which a plurality of cross-sectional strip-like portions extending in a crossing direction with respect to the electrode main surface are periodically formed, and one electrode side of the cross-sectional stripe-like portion A cross-sectional view comb-like structure comprising a base part connecting the plurality of cross-sectional view strip-like parts,
The electron-accepting layer includes a cross-sectional stripe-like portion in which a plurality of cross-sectional strip-like portions extending in a crossing direction with respect to the electrode main surface are periodically formed, and the other electrode side of the cross-sectional stripe-like portion A cross-sectional view comb-like structure comprising a base part connecting the plurality of cross-sectional view strip-like parts,
It is preferable that the mixed layer is formed along a comb-teeth shape in a sectional view of the electron donating layer and the electron accepting layer.

The first method for producing a photoelectric conversion element of the present invention is as follows.
A method for producing the photoelectric conversion element of the present invention,
Forming one of the electron donating layer and the electron accepting layer;
On the one layer, a coating agent containing at least one solvent including a constituent component of the other layer of the electron donating layer and the electron accepting layer and a solvent in which the one layer is dissolved was applied. And removing the at least one solvent to form the other layer.

The second method for producing a photoelectric conversion element of the present invention is as follows.
The method for producing the photoelectric conversion element of the present invention, wherein the electron donating layer and the electron accepting layer have a comb-like structure in sectional view,
A flat film made of a constituent material of one of the electron donating layer and the electron accepting layer is formed, and the flat film corresponds to the comb-like pattern in cross-sectional view of the one layer. When the melting point of the constituent material of the one layer is T _m (° C.), the mold having the reverse pattern is pressed within a temperature range of T _m −100 (° C.) or more and less than T _m (° C.), Forming into a comb-like pattern in cross-sectional view and forming the one layer;
On the one layer, a coating agent containing at least one solvent including a constituent component of the other layer of the electron donating layer and the electron accepting layer and a solvent in which the one layer is dissolved was applied. And removing the at least one solvent to form the other layer.

The solar cell of the present invention includes the above-described photoelectric conversion element of the present invention.

According to the present invention in which a mixed layer in which the material of the electron donating layer and the material of the electron accepting layer are mixed is formed in the electron donating / accepting bonding layer, the adhesion between the electron donating layer and the electron accepting layer is improved. It is possible to provide a non-bulk heterojunction photoelectric conversion element that can improve the charge separation efficiency and the photoelectric conversion efficiency.
According to the present invention in which the electron donating layer and the electron accepting layer have a comb-like structure in cross-sectional view in accordance with the above configuration, the interface area between the electron donating layer and the electron accepting layer can be increased, It is possible to provide a non-bulk heterojunction photoelectric conversion element that has good adhesion between the electron donating layer and the electron accepting layer and can improve charge separation efficiency and photoelectric conversion efficiency.

It is a schematic cross section of the photoelectric conversion element of 1st Embodiment which concerns on this invention. It is a partial expanded sectional view of the photoelectric conversion element of FIG. It is a figure which shows the example of a plane pattern of the active layer of a cross-sectional view comb-tooth type structure. It is a figure which shows the example of a plane pattern of the other active layer of a cross-sectional view comb-tooth type structure. It is a figure which shows the other plane pattern example of the active layer of a cross-sectional view comb-tooth type structure. It is a schematic cross section of the photoelectric conversion element of 2nd Embodiment which concerns on this invention. It is a schematic cross section of the photoelectric conversion element of 3rd Embodiment which concerns on this invention.

“First Embodiment”
With reference to drawings, the photoelectric conversion element of 1st Embodiment which concerns on this invention, and its manufacturing method are demonstrated.
FIG. 1 is a schematic cross-sectional view of the photoelectric conversion element of this embodiment. FIG. 2 is a partially enlarged cross-sectional view of the photoelectric conversion element of FIG. 3A to 3C are diagrams (sectional views taken along the line III-III in FIG. 1) showing examples of planar patterns of the active layer having a comb-like structure in cross-sectional view.

As shown in FIG. 1, the photoelectric conversion element 101 according to the present embodiment includes a pair of electrodes 30 and 40 that are arranged so that the electrode main surfaces face each other, and a comb-like cross-sectional view formed therebetween. An electron donating layer 10 (p layer) and a comb-like electron accepting layer 20 (n layer) in cross section are provided.
The comb-like electron donor layer 10 in cross-sectional view and the electron-accepting layer 20 in cross-sectional comb shape are joined so that their comb teeth mesh with each other. The electron donating / accepting junction layer 1 is a layer in which the comb-like electron donating layer 10 in cross-section and the electron accepting layer 20 in cross-section are engaged with each other and joined.

In the figure, the electrode main surface of one electrode (lower electrode in the figure) 30 is denoted by reference numeral 30A, and the electrode main surface of the other electrode (the upper electrode in the figure) 40 is denoted by reference numeral 40A.
In the present embodiment, one electrode 30 is formed on a substrate (not shown). The photoelectric conversion element 101 according to this embodiment has an electron donor / acceptor bonding layer 1 formed on an electrode substrate having one electrode 30 formed on the substrate, and the other electrode 40 formed thereon. is there.
On the substrate, the other electrode 40, the electron donating / accepting bonding layer 1, and the one electrode 30 may be formed in this order.
The electrode main surfaces 30A and 40A of the electrodes 30 and 40 are surfaces parallel to the substrate surface.
Any substrate can be used as the substrate. In order to manufacture the photoelectric conversion element 101, it is preferable to use a substrate, but the substrate is not essential.

The electron donor layer 10 includes a cross-sectional stripe-like portion 12 in which a plurality of cross-sectional strip-like portions 12A extending in a direction intersecting, preferably substantially perpendicular to the electrode main surface 30A, are formed at a predetermined pitch, and a cross-sectional stripe The base portion 11 is formed on the one electrode 30 side of the shape portion 12 and connects the plurality of cross-sectional strip-like portions 12A.
The electron-accepting layer 20 includes a cross-sectional stripe-like portion 22 in which a plurality of cross-sectional strip-like portions 22A extending in a crossing direction, preferably substantially perpendicular to the electrode main surface 40A, are formed at a predetermined pitch, and a cross-sectional stripe The base portion 21 is formed on the other electrode 40 side of the shape portion 22 and connects the plurality of cross-sectional strip-like portions 22A.

In the present embodiment, the plurality of cross-sectional strip-shaped portions 12A of the electron donating layer 10 and the plurality of cross-sectional strip-shaped portions 22A of the electron accepting layer 20 extend in a substantially vertical direction with respect to the electrode main surfaces 30A and 40A. .
In the present specification, “substantially vertical direction” means a completely vertical direction and an angular direction of ± 5 ° from the completely vertical direction.

As described above, the comb-like electron donor layer 10 in cross-section and the electron-accepting layer 20 in cross-section are joined so that their comb teeth mesh with each other. The short strip portions 12A and the plurality of cross sectional strip portions 22A of the electron accepting layer 20 are joined alternately.

In the present embodiment, a mixed layer 1M in which the material of the electron donating layer 10 and the material of the electron accepting layer 20 are mixed is formed in the electron donating / accepting bonding layer 1. The mixed layer 1M is formed along a comb-teeth shape in a sectional view of the electron donating layer 10 and the electron accepting layer 20.
The mixed layer 1M includes a boundary portion between the cross-sectional strip portion 12A of the electron donating layer 10 adjacent to each other and the cross-sectional strip portion 22A of the electron accepting layer 20, and the cross-sectional strip portion 12A of the electron donating layer 10 and the electron accepting portion. The layer 20 is formed at a boundary portion with the base portion 21 and at a boundary portion between the strip-like portion 22 </ b> A in the electron accepting layer 20 and the base portion 11 of the electron donating layer 10.
In the drawing, in the electron donating / accepting bonding layer 1, the mixed layer 1M and the non-mixed layer in which the material of the electron donating layer and the material of the electron accepting layer are not mixed clearly form an interface. In practice, these interfaces may not be clear.
In the present embodiment, the interface (p / n interface) between the electron donating layer (p layer) 10 and the electron accepting layer (n layer) 20 contributing to charge separation is included in the mixed layer 1M.

By forming a mixed layer 1M in which the material of the electron donating layer 10 and the material of the electron accepting layer 20 are mixed in the electron donating / accepting bonding layer 1, the adhesion between the electron donating layer 10 and the electron accepting layer 20 is improved. Can be improved.

The layer thickness c of the mixed layer 1M is not particularly limited.
The layer thickness c of the mixed layer 1M may not be clearly measured.
The layer thickness of the mixed layer 1M in which the material of the electron donating layer 10 and the material of the electron accepting layer 20 are mixed is, for example, an ultrathin section prepared by cross-sectional processing, and observed with an electron microscope. Thickness can be determined.

In the electron donor / acceptor bonding layer 1, it is necessary that the movement path of electrons and holes generated at the charge separation interface (hereinafter referred to as “carrier” together) is communicated.
Since the electron donating layer 10 and the electron accepting layer 20 are in good contact with each other and a structure in which the carrier moving path generated at the charge separation interface is satisfactorily obtained is obtained, the layer thickness c of the mixed layer 1M is 0. The thickness is preferably 5 to 50 nm, more preferably 1 to 25 nm.
If the layer thickness c of the mixed layer 1M is less than 0.5 nm, there may be a portion where the mixed layer 1M is not formed between the electron donating layer 10 and the electron accepting layer 20, and a portion where the adhesion of these layers is lowered may occur. There is.
If the layer thickness c of the mixed layer 1M is more than 50 nm, the carrier moving path that moves in the electron donating / accepting junction layer 1 becomes difficult to communicate, and the carrier collection efficiency at the electrodes 30 and 40 may be reduced.

The stripe width “a” of the cross-sectional stripe portion 12 of the electron donating layer 10 and the stripe width “b” of the cross-sectional stripe portion 22 of the electron accepting layer 20 are not particularly limited.
In this embodiment, since the mixed layer 1M is formed in the electron donating / accepting bonding layer 1, the bonding interface between the electron donating layer 10 and the electron accepting layer 20 is not clear, and the layer thickness of these layers is clear. It may not be.
When the bonding interface between the electron donating layer 10 and the electron accepting layer 20 is not clear, the mixed layer 1M has half of the layer thickness belonging to the electron donating layer 10 and the other half belonging to the electron accepting layer 20. I reckon.

In the organic photoelectric conversion element, only the excitons that have reached the interface between the electron donating layer and the electron accepting layer are involved in charge separation among the generated excitons (excitons). The distance that the exciton reaches the charge separation interface (hereinafter referred to as “exciton diffusion length”) is considered to be 50 nm or less, although it varies depending on the chemical structure and purity of the material. Therefore, the interface between the electron donating layer and the electron accepting layer periodically exists at a distance of about twice the exciton diffusion length, and if the electrode is arranged in the direction perpendicular to the interface direction, the number of excitons that separate charges increases. Conversion efficiency is expected to improve.

The stripe width a of the stripe-like section 12 of the electron donor layer 10 and the stripe width b of the stripe-like section 22 of the electron accepting layer 20 are both exciton diffusion in order to increase excitons contributing to charge separation. The length is preferably not more than twice the length. In general, the exciton diffusion length of an organic semiconductor is considered to be 50 nm or less. In addition, it is difficult to make the stripe width a of the electron donating layer 10 and the stripe width b of the electron accepting layer 20 less than 5 nm.
For the above reasons, the stripe width a of the electron donating layer 10 and the stripe width b of the electron accepting layer 20 are both preferably 5 to 100 nm.
In other words, it is preferable that both the pitch of the stripe-like portion 12 in cross section of the electron donating layer 10 and the pitch of the stripe-like portion 22 in cross section of the electron accepting layer 20 are 10 to 200 nm.
The stripe width a of the electron donating layer 10 and the stripe width b of the electron accepting layer 20 may be the same or non-identical.

The layer thickness d of the active layer 1 </ b> A composed of the cross-sectional stripe portion 12 of the electron donating layer 10 and the cross-sectional stripe portion 22 of the electron accepting layer 20 is not particularly limited.
When the bonding interface between the base 11 and the electron-accepting layer 20 or the bonding interface between the base 21 and the electron-accepting layer 10 is not clear, half of the layer thickness of the mixed layer 1M belongs to the active layer 1A, and half is the base 11 Alternatively, it is regarded as belonging to the base 21.
When the stripe width a of the electron donating layer 10 and the stripe width b of the electron accepting layer 20 are the same, the layer thickness d of the active layer 1A is preferably 2 to 40 times the stripe widths a and b, more preferably 5 ~ 20 times.
The thickness d of the active layer 1A is such that when the stripe width a of the electron donating layer 10 and the stripe width b of the electron accepting layer 20 are not the same, the stripe width a of the electron donating layer 10 and the stripe width b of the electron accepting layer 20 are the same. Of these, it is preferably 40 times or less, more preferably 2 times or more of the smaller one, and more preferably 20 times or less of 5 or more times the smaller one.
If the layer thickness d of the active layer 1A is less than the lower limit, the light absorption effect and the effect of increasing the charge separation interface area may not be sufficiently obtained, and if it exceeds the upper limit, the production may be difficult.

The layer thickness e of the base 11 of the electron donating layer 10 is not particularly limited.
When the bonding interface between the base 11 and the electron-accepting layer 20 is not clear, it is considered that half of the layer thickness of the mixed layer 1M belongs to the base 11.
The layer thickness e of the base 11 is preferably 5 to 100 nm, more preferably 5 to 50 nm, as is the stripe width a of the electron donating layer 10.
Since the base 11 of the electron donating layer 10 has a bonding interface with the electron accepting layer 20, it is preferable that the thickness be close to the exciton diffusion length.
In the configuration of the present embodiment in which the base 11 of the electron donating layer 10 and one electrode 30 are joined, the base 11 of the electron donating layer 10 has a sufficient thickness ( Specifically, it is preferably 5 nm or more.
If the thickness of the base 11 of the electron donating layer 10 is insufficient in the configuration of the present embodiment in which the base 11 of the electron donating layer 10 and the one electrode 30 are joined, the electron accepting layer 20 and the one electrode 30 If they are too close together, there is a risk of rectification deterioration or short circuit. It is difficult to manufacture the base 11 with a layer thickness e of less than 5 nm.
On the other hand, when the layer thickness e of the base 11 is larger than 100 nm, the resistance to carrier movement after charge separation increases, and the carrier collection efficiency at the electrode may be reduced.

In the second embodiment to be described later, a (semi) conductor layer 50 is interposed between the base portion 11 of the electron donating layer 10 and the one electrode 30, and the layer thickness e of the base portion 11 of the electron donating layer 10 is thin. However, deterioration of rectification and short circuit are unlikely to occur. Therefore, in this case, the thickness e of the base 11 of the electron donating layer 10 is preferably 1 to 100 nm.

The layer thickness f of the base 21 of the electron accepting layer 20 is not particularly limited, and is the same as the layer thickness e of the base 11 of the electron donating layer 10.
When the bonding interface between the base 21 and the electron donating layer 10 is not clear, it is considered that half of the layer thickness of the mixed layer 1M belongs to the base 21.
The layer thickness f of the base 21 is preferably 5 to 100 nm, more preferably 5 to 50 nm, like the stripe width b of the electron accepting layer 20.
Since the base 21 of the electron-accepting layer 20 has a bonding interface with the electron-donating layer 10, the thickness is preferably close to the exciton diffusion length.
In the configuration of the present embodiment in which the base 21 of the electron-accepting layer 20 and the other electrode 40 are joined, the base 21 of the electron-accepting layer 20 has a sufficient thickness (in order to avoid adverse effects on rectification and short-circuiting). Specifically, it is preferably 5 nm or more.
If the base 21 of the electron accepting layer 20 is insufficient in thickness in the configuration of the present embodiment in which the base 21 of the electron accepting layer 20 and the other electrode 40 are joined, the electron donating layer 10 and the other electrode 40 If they are too close together, there is a risk of rectification deterioration or short circuit. It is also difficult to make the layer thickness f less than 5 nm.
On the other hand, if the layer thickness f is larger than 100 nm, the resistance to the movement of carriers after charge separation increases, and the carrier collection efficiency at the electrode may be reduced.
In the second embodiment described later in which a (semi) conductor layer 60 is interposed between the base 21 of the electron accepting layer 20 and the other electrode 40, the layer thickness f of the base 21 of the electron accepting layer 20 is thin. However, deterioration of rectification and short circuit are unlikely to occur. Therefore, in this case, the thickness e of the base 11 of the electron donating layer 10 is preferably 1 to 100 nm.

The layer thickness of the electron donating / accepting bonding layer 1 (= total thickness of the active layer 1A, the base 11 of the electron donating layer 10 and the base 21 of the electron accepting layer 20) is not particularly limited, and is within a range of 20 to 4400 nm. It is preferred that it is in the range of 100 to 1000 nm. If the thickness of the electron donating / accepting bonding layer 1 is less than 100 nm, the amount of light absorption may be insufficient, and if it exceeds 1000 nm, it may be difficult to produce the electron donating / accepting bonding layer 1.

An example of a planar pattern of the active layer 1A will be described with reference to FIGS. 3A to 3C. 3A to 3C are sectional views taken along line III-III in FIG.

The planar pattern of the active layer 1A shown in FIG. 3A is an example in which the electron donating layer 10 and the electron accepting layer 20 are both formed in a stripe shape in plan view.

The planar pattern of the active layer 1A shown in FIG. 3B is an example in which the electron-accepting layer 20 is patterned in a planar view lattice shape, and the electron-donating layer 10 is formed in a planar view matrix shape.
In the example shown in FIG. 3B, the planar shape of each sectional view strip-shaped portion 12 </ b> A of the electron donating layer 10 is rectangular. The planar shape of each sectional view strip portion 12A of the electron donating layer 10 is arbitrary, such as a perfect circle or an ellipse.

The planar pattern of the active layer 1A shown in FIG. 3C is an example in which the electron donor layer 10 is formed in a pattern in a planar view and the electron accepting layer 20 is formed in a matrix in a plan view.
In the example shown in FIG. 3C, the planar shape of each cross-sectional view strip portion 22A of the electron-accepting layer 20 is rectangular. The planar shape of each cross-sectional strip-shaped portion 22A of the electron accepting layer 20 is arbitrary such as a perfect circle or an ellipse.

In the photoelectric conversion element 101, the material of the electrodes 30 and 40 is not particularly limited as long as it is a conductor, and examples thereof include metals, alloys, metalloids, metal compounds, and organic conductors. These may contain a dopant. At least one of the electrodes needs to be a translucent electrode.
Examples of the material of the electrodes 30 and 40 include metals such as gold, silver, platinum, and aluminum and alloys thereof, indium tin oxide (ITO), fluorine-doped tin oxide (FTO), and aluminum-doped zinc oxide (AZO). Metal oxides, carbon nanotubes, and semimetals such as graphene.

The film thickness of the electrodes 30 and 40 is not particularly limited and is preferably 5 to 200 nm. If the film thickness of the electrodes 3 and 40 is too thin, the sheet resistance increases, and the generated carriers cannot be sufficiently transmitted to the external circuit. If the film thickness of the electrodes 30 and 40 is too thick, it is difficult to manufacture and the cost is increased.

The method for forming the electrodes 30 and 40 is not particularly limited. For example, a vapor deposition method such as a vacuum deposition method, a sputtering method, and a CVD method, or a spin coating method, a dip coating method, and a screen printing method. And liquid phase film forming methods.

The material of the electron donor layer 10 is not particularly limited, and an organic semiconductor is preferable, and a crystalline organic polymer is more preferable.
Examples of the material of the electron donating layer 10 include polymer compounds such as polythiophene derivatives, polyfluorene derivatives, and polyphenylene vinylene derivatives and copolymers thereof, phthalocyanine derivatives and metal complexes thereof, porphyrin derivatives and metal complexes thereof, pentacene, and the like. And low molecular weight compounds such as acene derivatives and diamine derivatives. Poly (3-hexylthiophene), poly (3- (2-methylhexane) oxycarbonyldithiophene), 3- (6-bromohexyl) thiophene.3-hexylthiophene copolymer, and the like are preferable.
The electron donor layer 10 can contain an inorganic semiconductor in accordance with the organic semiconductor as long as there is no particular problem. The electron donor layer 10 can contain inevitable impurities.

The material of the electron accepting layer 20 is not particularly limited, and an organic semiconductor is preferable.
Examples of the material of the electron accepting layer 20 include fullerene derivatives, perylene derivatives, and naphthalene derivatives. Phenyl C61 butyric acid methyl ester and phenyl C71 butyric acid methyl ester are preferred.
The electron-accepting layer 20 can contain an inorganic semiconductor in accordance with the organic semiconductor as long as there is no particular problem. The electron accepting layer 20 can contain inevitable impurities.

The manufacturing method of the photoelectric conversion element 101 of this embodiment is not particularly limited.
When the electron donating layer 10 and / or the electron accepting layer 20 is made of an organic semiconductor, the photoelectric conversion element 101 can be manufactured using a nanoimprint method as follows, for example.

The photoelectric conversion element 101 of this embodiment is
A flat film made of a constituent material of one of the electron donating layer 10 and the electron accepting layer 20 is formed, and the inversion corresponding to the comb-like pattern in cross-sectional view of the one layer is formed on the flat film. When the mold having the pattern is pressed within a temperature range of T _m -100 (° C.) or higher and lower than T _m (° C.) when the melting point of the constituent material of the one layer is T _m (° C.), Forming a comb-like pattern to form the one layer;
On the one layer, a coating agent containing at least one solvent including a constituent component of the other layer of the electron donating layer 10 and the electron accepting layer 20 and a solvent in which the one layer is dissolved was applied. Then, it can manufacture by the manufacturing method which removes at least 1 sort (s) of solvent and has the process of forming said other layer.

For example, when the electron donor layer 10 is formed first out of the electron donor layer 10 and the electron acceptor layer 20, the photoelectric conversion element 101 of this embodiment can be manufactured as follows.

A flat film made of the constituent material of the electron donating layer 10 is formed on the substrate on which one electrode 30 is formed. For this flat film, a mold having a comb-like pattern in cross section of the electron donating layer 10 and a reversal pattern corresponding to the planar pattern as shown in FIGS. 3A to 3C is used as a constituent material of the electron donating layer 10. When the melting point is T _m (° C.), pressing is performed within a temperature range of T _m −100 (° C.) or more and less than T _m (° C.) to transfer the mold pattern. By doing so, the flat film can be formed into a comb-like pattern in sectional view.

After the temperature of the electron donating layer 10 is lowered and solidified, a solvent in which the constituent components of the electron accepting layer 20 and the electron donating layer 10 previously formed are dissolved on the condition that the comb-like structure in cross-sectional view is not broken. A coating agent containing at least one kind of solvent is applied, and at least one kind of solvent is removed to form the electron-accepting layer 20.
In the process of forming the electron-accepting layer 20, when the coating agent is applied onto the electron-donating layer 10, a part of the electron-donating layer 10 is dissolved, and a part of the electron-donating layer 10 previously formed and its A mixed layer 1M in which a part of the electron accepting layer 20 formed thereon is mixed is formed.
As described above, the electron donating / accepting bonding layer 1 having a comb-teeth structure in cross section can be formed.
Thereafter, the other electrode 40 is formed on the electron donating / accepting bonding layer 1 to manufacture the photoelectric conversion element 101.

The method for forming the flat film to be the electron donating layer 10 is not particularly limited, and vapor phase film formation methods such as vacuum deposition and sputtering, or liquid phase formation such as spin coating, dip coating, and spray coating. Examples thereof include a membrane method.
The film forming method of the electron accepting layer 20 is not particularly limited as long as it is a liquid phase film forming method, and examples thereof include a spin coat method, a dip coat method, and a spray coat method.
The flat film and the electron accepting layer 20 to be the electron donating layer 10 may be formed in a plurality of stages by changing the film forming conditions and the film forming method.

The mold used for the nanoimprint method is a mold made of silicon, glass, metal, or the like, and having a concavo-convex pattern corresponding to the cross-sectional comb-teeth structure of the electron donor layer 10 on the surface thereof. A method for producing such a mold is not particularly limited. For example, a resist pattern is formed by electron beam drawing on a thermally oxidized silicon substrate, and the substrate is dry-etched using the resist pattern as a mask. On the other hand, a resist pattern is formed by electron beam drawing and the substrate is dry-etched using the resist pattern as a mask, and a resist pattern is formed on the silicon substrate by electron beam drawing and the substrate is wet-etched using the resist pattern as a mask. Etc.

According to said manufacturing method, the photoelectric conversion element 101 which has the favorable pattern precision of the electron donor and acceptance | joining joining layer 1, high uniformity, and shows favorable charge separation and favorable photoelectric conversion efficiency can be manufactured.
In the manufacturing method described above, the mixed layer 1M is formed at the same time when the electron-accepting layer 20 is formed.

The non-mixed layer of the electron donating layer 10, the mixed layer 1M, and the non-mixed layer of the electron accepting layer 20 may be formed in separate steps.
For example, after forming the electron donating layer 10 having a comb-like pattern in cross section, a coating agent for a mixed layer including an electron donating material and an electron accepting material is applied, the solvent is removed, and the mixed layer 1M is formed. After film formation, an electron-accepting layer can be formed. In this case, the mixed layer may be formed by vapor deposition such as co-evaporation. The electron accepting layer may also be formed by vapor deposition such as vapor deposition.
Even if the non-mixed layer of the electron donating layer 10, the mixed layer 1M, and the non-mixed layer of the electron accepting layer 20 are formed in separate steps, the mixed layer 1M containing the electron donating material and the electron accepting material is interposed. Thus, the adhesion between the electron donating layer 10 and the electron accepting layer 20 can be enhanced.

As described above, the mixed layer 1M in which the material of the electron donating layer 10 and the material of the electron accepting layer 20 are mixed is formed in the electron donating / accepting bonding layer 1, and the electron donating layer 10, the electron accepting layer 20, According to the present embodiment having a comb-like structure in cross section, the interface area between the electron donating layer 10 and the electron accepting layer 20 can be increased, and the electron donating layer 10 and the electron accepting layer 20 are in close contact with each other. Thus, it is possible to provide a non-bulk heterojunction photoelectric conversion element 101 that has good characteristics and can improve charge separation efficiency and photoelectric conversion efficiency.

“Second Embodiment”
A photoelectric conversion element according to a second embodiment of the present invention will be described with reference to the drawings.
FIG. 4 is a schematic cross-sectional view of the photoelectric conversion element of this embodiment.
The basic configuration of the present embodiment is the same as that of the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.

As in the first embodiment, the photoelectric conversion element 102 according to this embodiment includes a pair of electrodes 30 and 40 that are disposed so that the electrode principal surfaces face each other, and a comb-like shape in cross-sectional view formed therebetween. And an electron donating / accepting bonding layer 1 comprising a comb-like electron accepting layer 20 (n layer) in cross section.
Also in this embodiment, a mixed layer 1M in which the material of the electron donating layer 10 and the material of the electron accepting layer 20 are mixed is formed in the electron donating / accepting bonding layer 1. The mixed layer 1M is formed along a comb-teeth shape in a sectional view of the electron donating layer 10 and the electron accepting layer 20.
An example of a planar pattern (III-III sectional view) of the active layer having a comb-like structure in cross section is the same as that shown in FIGS. 3A to 3C in the first embodiment.

In the present embodiment, a semiconductor layer and / or a conductor layer is further formed between the base 11 of the electron donating layer 10 and one electrode 30 and / or the base 21 of the electron accepting layer 20 and the other electrode 40. ing. Hereinafter, the “semiconductor layer and / or conductor layer” is referred to as a (semi) conductor layer.
In the present embodiment, a (semi) conductor layer 50 is formed between the base 11 of the electron donating layer 10 and the one electrode 30, and (half) between the base 21 of the electron accepting layer 20 and the other electrode 40. A conductor layer 60 is formed.

The material of the (semi) conductor layers 50 and 60 is not particularly limited, and examples thereof include polymer compounds such as poly-3,4-ethylenedioxythiophene, polystyrene sulfonic acid, and polyaniline, and semimetals such as carbon nanotubes. And metal compounds such as titanium oxide, molybdenum oxide, and lithium fluoride, and alloys such as aluminum alloy and magnesium alloy.

The method of forming the (semi) conductor layers 50 and 60 is not particularly limited. For example, vapor deposition methods such as vacuum deposition, sputtering, and CVD, spin coating, dip coating, And liquid phase film forming methods such as a screen printing method.

The photoelectric conversion element 102 of this embodiment includes the electron donating / accepting bonding layer 1 having the same structure as that of the first embodiment, and the same effects as those of the first embodiment can be obtained.
The photoelectric conversion element 102 of the present embodiment can be manufactured in the same manner as in the first embodiment, except that the number of (semi) conductor layers 50 and 60 is increased.
A mixed layer 1M in which the material of the electron donating layer 10 and the material of the electron accepting layer 20 are mixed is formed in the electron donating / accepting bonding layer 1, and the electron donating layer 10 and the electron accepting layer 20 have a comb-teeth shape in cross section. According to this embodiment having a structure, the interface area between the electron donating layer 10 and the electron accepting layer 20 can be increased, the adhesion between the electron donating layer 10 and the electron accepting layer 20 is good, and charge separation is performed. A non-bulk heterojunction photoelectric conversion element 102 that can improve efficiency and photoelectric conversion efficiency can be provided.

“Third Embodiment”
A photoelectric conversion element according to a third embodiment of the present invention will be described with reference to the drawings.
FIG. 5 is a schematic cross-sectional view of the photoelectric conversion element of this embodiment.
The basic configuration of the present embodiment is the same as that of the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.

The photoelectric conversion element 103 according to this embodiment includes a pair of electrodes 30 and 40 that are disposed so that the electrode main surfaces face each other, and an electron donating layer 70 (p layer) and an electron accepting layer 80 that are formed therebetween. And an electron donating / accepting bonding layer 2 made of (n layer). The photoelectric conversion element 103 of the present embodiment is a flat-coupled photoelectric conversion element in which the electron donating layer 70 and the electron accepting layer 80 are both solid films.
In the present embodiment, a mixed layer 2M in which the material of the electron donating layer 70 and the material of the electron accepting layer 80 are mixed is formed in the electron donating / accepting bonding layer 2.

In the drawing, in the electron donating / accepting bonding layer 2, the mixed layer 2M and a non-mixed layer in which the material of the electron donating layer 70 and the material of the electron accepting layer 80 are not mixed clearly form an interface. In practice, these interfaces may not be clear.
In the present embodiment, the interface (p / n interface) between the electron donating layer (p layer) 70 and the electron accepting layer (n layer) 80 contributing to charge separation is included in the mixed layer 2M.

Also in the flat-coupled photoelectric conversion element 103, the electron donating layer 2M in which the material of the electron donating layer 70 and the material of the electron accepting layer 80 are mixed is formed in the electron donating / accepting bonding layer 2. Adhesiveness between 70 and the electron-accepting layer 80 can be improved.
The layer thickness of the mixed layer 2M is not particularly limited.
The layer thickness of the mixed layer 2M may not be clearly measured.
As in the first embodiment, the electron donating layer 70 and the electron accepting layer 80 are in good contact with each other, the effect of increasing the charge separation interface area is obtained, and the movement path of carriers generated at the charge separation interface is well communicated. In order to obtain a stable structure, the layer thickness of the mixed layer 2M is preferably 0.5 to 50 nm.
If the layer thickness of the mixed layer 2M is less than 0.5 nm, there may be a portion where the mixed layer 2M is not formed between the electron donating layer 70 and the electron accepting layer 80, and there may be a portion where the adhesion of these layers is lowered. In addition, there is a case where the effect of increasing the charge separation interface area cannot be sufficiently obtained.
If the layer thickness of the mixed layer 2M exceeds 50 nm, the carrier moving path that moves in the electron donating / accepting junction layer 2 becomes difficult to communicate, and the carrier collection efficiency at the electrodes 30 and 40 may be reduced.

The layer thickness of the electron donating layer 10 and the layer thickness of the electron accepting layer 20 are not particularly limited.
In this embodiment, since the mixed layer 2M is formed in the electron donating / accepting bonding layer 2, the bonding interface between the electron donating layer 70 and the electron accepting layer 80 is not clear, and the layer thickness of these layers is clear. It may not be.
As in the first embodiment, when the bonding interface between the electron donating layer 70 and the electron accepting layer 80 is not clear, the mixed layer 2M has half of the layer thickness belonging to the electron donating layer 70 and the other half is the electron accepting layer. Consider belonging to layer 80.

Both the thickness of the electron donating layer 70 and the thickness of the electron accepting layer 80 are preferably 50 to 250 nm.
If the layer thickness of the electron donating layer 70 and the electron accepting layer 80 is less than 50 nm, sufficient light absorption may not be performed and the photoelectric conversion efficiency may be reduced. If the layer thickness of the electron donating layer 70 and the electron accepting layer 80 exceeds 250 nm, the resistance to carrier movement after charge separation increases, and the carrier collection efficiency at the electrode may be reduced.
The thickness of the electron donating / accepting bonding layer 2 which is an active layer composed of the electron donating layer 70 and the electron accepting layer 80 is preferably 50.5 to 300 nm.
The layer thickness of the electron donating layer 70 and the layer thickness of the electron accepting layer 80 may be the same or different.

The photoelectric conversion element 103 of this embodiment is
Forming one of the electron donating layer 70 and the electron accepting layer 80;
On the one layer, a coating agent including at least one solvent including a constituent component of the other of the electron donating layer 70 and the electron accepting layer 80 and a solvent in which the one layer is dissolved was applied. Then, it can manufacture by the manufacturing method which removes a solvent and has the process of forming said other layer.

According to the present embodiment in which the mixed layer 2M in which the material of the electron donating layer 70 and the material of the electron accepting layer 80 are mixed is formed in the electron donating / accepting bonding layer 2, the electron donating layer 70 and the electron accepting layer are formed. It is possible to provide a planar coupling type photoelectric conversion element 103 that has good adhesion to the layer 80 and can improve charge separation efficiency and photoelectric conversion efficiency.

"Solar cell"
The photoelectric conversion elements 101 to 103 of the first to third embodiments can be used as solar cells with a cover glass and a protective film attached thereto.

Examples and comparative examples according to the present invention will be described.

In the following Examples 1 to 3, the photoelectric conversion elements 101 to 103 of the above embodiment were produced. The planar pattern of the active layer was the stripe pattern shown in FIG. 3A.
Comparative Examples 1 to 3 were obtained in the same manner as Examples 1 to 3, except that the mixed layer was not formed.

<Dimensions of comb-tooth structure in cross-sectional view, dimensions of mold>
The dimensions of the cross-sectional comb structure in Examples 2 and 3 were as follows.
Stripe width a of the electron donating layer 10 (including half the thickness of the mixed layer 1M) = 100 nm, stripe width b of the electron accepting layer 20 (including the half thickness of the mixed layer 1M) = 100 nm, layer thickness of the active layer 1A d = 500 nm, thickness e of the base portion 11 of the electron donating layer 10 (including half the thickness of the mixed layer 1M) = 50 nm, thickness f of the base portion 21 of the electron accepting layer 20 (including half the thickness of the mixed layer 1M) ) = 50 nm.
In Examples 2 and 3, the mold used for pattern formation of the electron donating layer 10 has a plurality of trenches having a width of 100 nm, a length of 6 mm, a depth of 500 nm, and a pitch of 200 nm. The area in plan view of the portion where the mold structure was formed was 6 mm × 6 mm.

<Conversion efficiency>
In the following examples, the conversion efficiency of the photoelectric conversion element was measured using a solar simulator. The conversion efficiency was calculated by irradiating simulated sunlight with a xenon lamp (500 W) (AM1.5G, 1 kW / m ² ) and measuring an IV curve.

<Example 1>
The photoelectric conversion element 103 having the structure shown in FIG. 5 was produced as follows.
Poly (3-hexylthiophene) (hereinafter abbreviated as “P3HT”) is spin-coated on an electrode substrate having a thickness of 0.7 mm on which an ITO transparent electrode having a thickness of 100 nm is formed, and heat treatment at 150 ° C. for 30 minutes. And an electron donating layer having a layer thickness of 100 nm was formed.
Next, a solution in which phenyl C61 butyric acid methyl ester (hereinafter abbreviated as “PCBM”) is dissolved in a dichloromethane / chloroform mixed solvent is spin-coated on the electron donor layer, and heat treatment is performed at 150 ° C. for 30 minutes to obtain a layer thickness. A 100 nm electron-accepting layer was formed.
As described above, an electron donating / accepting junction layer composed of an electron donating layer and an electron accepting layer was formed.
In the process of forming the electron donating / accepting bonding layer, when the PCBM solution is applied onto the electron donating layer, the upper layer portion of the electron donating layer is dissolved, and the upper layer portion of the electron donating layer previously formed and the upper layer portion are formed thereon. A mixed layer in which the lower layer portion of the filmed electron accepting layer was mixed was formed. The layer thickness c of the mixed layer was 20 nm. The layer thicknesses of the non-mixed layer of the electron donating layer and the non-mixed layer of the electron accepting layer were both 80 nm.
That is, among the electron donating layers having a layer thickness of 100 nm, 10 nm × 2 was a mixed layer and the remaining 80 nm was a non-mixed layer. Similarly, of the electron-accepting layer having a layer thickness of 100 nm, 10 nm × 2 was a mixed layer and the remaining 80 nm was a non-mixed layer.
Finally, Al was vacuum-deposited with a film thickness of 100 nm to obtain a photoelectric conversion element. As a result of measuring the conversion efficiency, it was 1.5%.

<Example 2>
P3HT was spin-coated on an electrode substrate having a thickness of 0.7 mm on which an ITO transparent electrode having a thickness of 100 nm was formed, and a heat treatment at 150 ° C. for 30 minutes was performed to form a P3HT layer having a thickness of 300 nm.
Next, using the above mold, the P3HT layer is heated and pressurized at 180 ° C. and 40 MPa to transfer the pattern of the mold, and then subjected to heat treatment at 150 ° C. for 30 minutes, a = 100 nm, d = 500 nm, e = 50 nm An electron donor layer having a comb-tooth structure in cross section was formed.
Next, a PCBM-dichloromethane / chloroform solution was spin-coated on the electron donating layer having a comb-tooth structure in cross-sectional view, and heat treatment was performed at 150 ° C. for 30 minutes to form an electron-accepting layer having b = 100 nm and f = 50 nm. .
As described above, an electron donating / accepting junction layer composed of an electron donating layer and an electron accepting layer was formed.
In the process of forming the electron donating / accepting bonding layer, a part of the electron donating layer is dissolved when the PCBM solution is applied on the electron donating layer having a comb-tooth structure in a cross-sectional view. A mixed layer was formed in which a portion of the electron-accepting layer formed thereon was mixed with a part of the electron-accepting layer. The mixed layer was formed along the surface shape of the electron donor layer having a comb-tooth structure in cross-sectional view formed in advance.
The layer thickness c of the mixed layer was 20 nm. The stripe width of the non-mixed layer of the electron donating layer and the stripe width of the non-mixed layer of the electron accepting layer were both 80 nm.
That is, of the stripe width of 100 nm of the electron donating layer, 10 nm × 2 was the mixed layer, and the remaining 80 nm was the non-mixed layer. Similarly, of the stripe width of 100 nm of the electron-accepting layer, 10 nm × 2 was the mixed layer, and the remaining 80 nm was the non-mixed layer.
Finally, Al was vacuum-deposited with a film thickness of 100 nm to obtain a device. As a result of measuring the conversion efficiency, it was 3.5%.

<Example 3>
Spin coat an aqueous solution of poly (3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) onto a 0.7 mm thick electrode substrate with a 100 nm thick ITO transparent electrode formed on the surface. And dried at 110 ° C. for 1 hr to form a (semi) conductor layer having a thickness of 30 nm.
Similarly to Example 2, an electron donating / accepting bonding layer having a comb-tooth structure in cross-sectional view was formed. As in Example 2, in the process of forming the electron donating / accepting bonding layer, when the PCBM solution was applied onto the electron donating layer, part of the electron donating layer was dissolved, and the electron donating layer formed earlier was dissolved. A mixed layer in which a part and a part of the electron-accepting layer formed thereon was mixed was formed. The dimensions a to f of the electron donating / accepting bonding layer were the same as those in Example 2.
Next, a titanium propoxide solution was spin-coated and dried at 110 ° C. for 1 hr to form a (semi) conductor layer having a thickness of 10 nm.
Finally, Al was vacuum-deposited with a film thickness of 100 nm to obtain a device. As a result of measuring the conversion efficiency, it was 3.9%.

<Comparative Example 1>
A comparative photoelectric conversion device was obtained in the same manner as in Example 1 except that a solution in which PCBM was dissolved only in a dichloromethane solvent was used instead of the PCBM-dichloromethane / chloroform solution. A mixed layer was not formed. The conversion efficiency was 0.8%.

<Comparative Example 2>
A comparative photoelectric conversion device was obtained in the same manner as in Example 2 except that a solution in which PCBM was dissolved only in a dichloromethane solvent was used instead of the PCBM-dichloromethane / chloroform solution. A mixed layer was not formed.
The dimensions a to f of the electron donating / accepting bonding layer were as follows.
a = 100 nm, d = 500 nm, e = 50 nm, b = 100 nm, f = 50 nm, c = 0 nm.
The conversion efficiency was 1.3%.

<Comparative Example 3>
A comparative photoelectric conversion device was obtained in the same manner as in Example 3 except that a solution in which PCBM was dissolved only in a dichloromethane solvent was used instead of the PCBM-dichloromethane / chloroform solution. A mixed layer was not formed.
The dimensions a to f of the electron donating / accepting bonding layer were as follows.
a = 100 nm, d = 500 nm, e = 50 nm, b = 100 nm, f = 50 nm, c = 0 nm.
The conversion efficiency was 1.7%.

The present invention is not limited to the above-described embodiment, and design changes can be made as appropriate without departing from the spirit of the present invention.

The photoelectric conversion element of the present invention can be preferably applied to solar cells, light emitting elements, light receiving elements, and other various sensors.

This application claims priority based on Japanese Patent Application No. 2011-010611 filed on Jan. 21, 2011, the entire disclosure of which is incorporated herein.

101 to 103 Photoelectric conversion elements 1, 2 Electron donating / accepting bonding layer 1A Active layer 1M, 2M Mixed layer 10, 70 Electron donating layer 11 Base 12 Striped portion 12A in cross section Striped portion 20, 80 Electron accepting layer 21 Base portion 22 Striped portion 22A in cross section Striped portion 30, 40 Electrode 30A, 40A Electrode main surface 50, 60 (Semi) conductor layer 70 Electron donating layer 80 Electron accepting layer

Claims (11)

1. A photoelectric conversion element comprising an electron donating / accepting junction layer in which an electron donating layer and an electron accepting layer are joined between a pair of electrodes arranged such that electrode principal surfaces face each other,
   A photoelectric conversion element in which a mixed layer in which a material for an electron donating layer and a material for the electron accepting layer are mixed is formed in the electron donating / accepting bonding layer.
2. 2. The photoelectric conversion element according to claim 1, wherein the mixed layer has a thickness of 0.5 to 50 nm.
3. The electron donating layer includes a cross-sectional stripe-like portion in which a plurality of cross-sectional strip-like portions extending in a crossing direction with respect to the electrode main surface are periodically formed, and one electrode side of the cross-sectional stripe-like portion A cross-sectional view comb-like structure comprising a base part connecting the plurality of cross-sectional view strip-like parts,
   The electron-accepting layer includes a cross-sectional stripe-like portion in which a plurality of cross-sectional strip-like portions extending in a crossing direction with respect to the electrode main surface are periodically formed, and the other electrode side of the cross-sectional stripe-like portion A cross-sectional view comb-like structure comprising a base part connecting the plurality of cross-sectional view strip-like parts,
   3. The photoelectric conversion element according to claim 1, wherein the mixed layer is formed along a comb-like shape in sectional view of the electron donating layer and the electron accepting layer.
4. The stripe width of the stripe portion in cross section of the electron donating layer and the stripe width of the stripe portion in cross section of the electron accepting layer are both 5 to 100 nm,
   And,
   The layer thickness of the active layer composed of the cross-sectional stripe part of the electron donating layer and the cross-sectional stripe part of the electron accepting layer is:
   When the stripe width of the electron donating layer and the stripe width of the electron accepting layer are the same, the stripe width is not less than 2 times and not more than 40 times,
   When the stripe width of the electron donating layer and the stripe width of the electron accepting layer are not the same, the stripe width of the electron donating layer and the stripe width of the electron accepting layer are more than twice the smaller one The photoelectric conversion element according to claim 3, which is 40 times or less of the larger one.
5. 5. The photoelectric conversion device according to claim 3, wherein the thickness of the base of the electron donating layer and the thickness of the base of the electron accepting layer are both 1 to 100 nm.
6. The semiconductor layer and / or the conductor layer is provided between the electron donating layer and the one electrode and / or between the electron accepting layer and the other electrode. Photoelectric conversion element.
7. The photoelectric conversion element according to any one of claims 1 to 6, wherein the electron donating layer and / or the electron accepting layer comprises an organic semiconductor.
8. The photoelectric conversion element according to claim 7, wherein the organic semiconductor is a crystalline organic polymer.
9. A method for producing a photoelectric conversion element according to any one of claims 1 to 8,
   Forming one of the electron donating layer and the electron accepting layer;
   After applying a solution containing a component of the other layer of the electron donating layer and the electron accepting layer and at least one solvent containing a solvent in which the one layer dissolves on the one layer. And a step of removing the at least one solvent to form the other layer.
10. A method for producing a photoelectric conversion element according to any one of claims 3 to 5,
    A flat film made of a constituent material of one of the electron donating layer and the electron accepting layer is formed, and the flat film corresponds to the comb-like pattern in cross-sectional view of the one layer. When the melting point of the constituent material of the one layer is T _m (° C.), the mold having the reverse pattern is pressed within a temperature range of T _m −100 (° C.) or more and less than T _m (° C.), Forming into a comb-like pattern in cross-sectional view and forming the one layer;
    On the one layer, a coating agent containing at least one solvent including a constituent component of the other layer of the electron donating layer and the electron accepting layer and a solvent in which the one layer is dissolved was applied. And a step of forming the other layer by removing the at least one solvent.
11. A solar cell comprising the photoelectric conversion element according to any one of claims 1 to 8.

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