JPWO2017200000A1 - Solid-junction photoelectric conversion element and manufacturing method thereof - Google Patents

Abstract

A solid junction photoelectric conversion element including a first conductive layer, a perovskite layer, and a second conductive layer in this order, wherein the perovskite in at least one adjacent layer among two adjacent layers adjacent to both sides of the perovskite layer The maximum height roughness (Rz) of the bonding surface K in contact with the layer is 1 nm or more, and the Rz is a peak height maximum value (Rp) and a valley depth maximum value within a reference length (L) in the bonding surface. A solid junction photoelectric conversion element which is the sum of (Rv).

Description

  The present invention relates to a solid junction photoelectric conversion element and a method for manufacturing the same. This application claims priority on May 17, 2016 based on Japanese Patent Application No. 2006-098417 for which it applied to Japan, and uses the content here.

  In recent years, it has been reported that a solid junction photoelectric conversion element including a power generation layer containing a perovskite compound exhibits high photoelectric conversion efficiency (Non-Patent Document 1), and has attracted attention as a new photoelectric conversion element. Starting with this report, further improvements in photoelectric conversion efficiency have been reported one after another (for example, Non-Patent Document 2).

“Efficient Hybrid Solar Cells Based on Meso-Superstructured Organometal Halide Perovskites” Science, 2012, 338, p643-647. “Solvent engineering for high-performance inorganic-organic hybrid perovskite solar cells” Nature Materials 2014, 13, p897-903.

  The inventors of the present invention have studied the production yield from the viewpoint of putting the above-described solid junction photoelectric conversion element into practical use, and have encountered a problem that a leak current is easily generated in the conventional manufacturing method and a large number of defective products are generated. .

  This invention is made | formed in view of the said situation, and provides the solid junction type photoelectric conversion element provided with the structure where a leak current does not generate | occur | produce easily, and its manufacturing method.

The present inventors examined the cause of the occurrence of the leakage current, and found that pinholes and / or cracks were generated in the perovskite layer. For this reason, it is considered that the first conductive layer side and the second conductive layer side sandwiching the perovskite layer are short-circuited through pinholes or cracks, and a leak current is generated. As a mechanism for generating pinholes and cracks, a solvent containing a perovskite compound is applied to a conductive support layer (adjacent layer described later) in the manufacturing process of a solid junction photoelectric conversion element, and the solvent contained in the coating film. It was considered that pinholes and cracks were generated when crystallization was carried out after drying.
Therefore, when the manufacturing process that suppresses the occurrence of pinholes and cracks during drying has been intensively studied, it has been found that the purpose can be achieved by roughening the surface roughness of the support layer to which the solution of the perovskite compound is applied, The present invention has been completed. The present invention is as follows.

[1] A solid junction photoelectric conversion element including a first conductive layer, a perovskite layer, and a second conductive layer in this order, and at least one adjacent layer of two adjacent layers adjacent to both sides of the perovskite layer The maximum height roughness (Rz) of the joint surface in contact with the perovskite layer is 1 nm or more, and Rz is a peak height maximum value (Rp) and a valley depth within the reference length (L) of the joint surface. A solid junction photoelectric conversion element which is the sum of maximum values (Rv).
[2] Of the area S (= L × Rz) of a quadrangle with the reference length (L) as a horizontal side and the Rz as a vertical side in a cross-sectional view including the joint surface in the thickness direction, The solid junction photoelectric conversion element according to [1], wherein the occupation ratio of the adjacent layer is 10 to 90%.
[3] The solid junction photoelectric conversion element according to [1] or [2], wherein the first conductive layer is an adjacent layer having an Rz of 1 nm or more.
[4] The anchor layer including fine particles is provided between the first conductive layer and the perovskite layer, and the anchor layer is an adjacent layer having the Rz of 1 nm or more. [1] or [2] Solid junction type photoelectric conversion element.
[5] An N-type semiconductor layer is provided between the first conductive layer and the perovskite layer, and the N-type semiconductor layer is an adjacent layer having the Rz of 1 nm or more, according to [1] or [2] The solid junction photoelectric conversion element described.
[6] An N-type semiconductor layer and an anchor layer containing fine particles are provided in this order between the first conductive layer and the perovskite layer, and the anchor layer is an adjacent layer having an Rz of 1 nm or more. [1] or [2].
[7] An N-type semiconductor layer is provided between the first conductive layer and the perovskite layer, and the N-type semiconductor layer is an adjacent layer having an Rz of 1 nm or more. One conductive layer is adjacent, and the maximum height roughness (Rz ′) of the bonding surface in contact with the N-type semiconductor layer in the first conductive layer is 1 nm or more, and the Rz ′ is the value of the first conductive layer The solid junction photoelectric conversion element according to [1] or [2], which is a sum of a peak height maximum value (Rp) and a valley depth maximum value (Rv) within a reference length (L) on the bonding surface.
[8] A P-type semiconductor layer is provided between the perovskite layer and the second conductive layer, and the P-type semiconductor layer is an adjacent layer having the Rz of 1 nm or more. [1] to [7] The solid junction photoelectric conversion element according to any one of the above.
[9] A base material in contact with the surface of the first conductive layer opposite to the perovskite layer is provided, and a maximum height roughness (Rz ″) of a bonding surface in contact with the first conductive layer in the base material is 1 nm. The Rz ″ is the sum of the peak height maximum value (Rp) and the valley depth maximum value (Rv) within the reference length (L) on the joint surface of the base material [1] to [8] The solid junction photoelectric conversion element according to any one of [8].
[10] The Rz (Rz-a) in the adjacent layer on the first conductive layer side and the Rz (Rz-b) in the adjacent layer on the second conductive layer side are 1 nm or more, and the (Rz The solid junction photoelectric conversion element according to any one of [1] to [9], wherein the roughness ratio represented by -a) / (Rz-b) is 0.1 or more and 1000 or less.
[11] A method for producing a solid junction photoelectric conversion device comprising a perovskite layer and an adjacent layer having a bonding surface in contact with the perovskite layer, the compound forming the perovskite layer on the bonding surface of the adjacent layer And a step of forming a perovskite layer by drying the coating film, and a maximum height roughness (Rz) of the joint surface is 1 nm. The method for manufacturing a solid junction photoelectric conversion element, wherein Rz is the sum of the peak height maximum value (Rp) and the valley depth maximum value (Rv) within the reference length (L) of the bonding surface. .
[12] The method for producing a solid junction photoelectric conversion element according to [11], wherein the coating film is dried by blowing hot air of 40 to 60 ° C. on the coating film to form the perovskite layer.
[13] The solid junction photoelectric conversion device according to [11] or [12], wherein a poor solvent for the compound is dropped onto the coating film, and then the coating film is dried to form the perovskite layer. Method.

In the solid junction photoelectric conversion element of the present invention, the bonding area of the adjacent layer bonded to the perovskite layer has a specific roughness, so that the bonding area between the perovskite layer and the adjacent layer is increased. With this structure, not only the generation of cracks that may occur during manufacturing but also the generation of cracks that may occur due to bending or distortion during use can be suppressed, and the generation of leakage current can be reduced.
According to the method for producing a solid junction photoelectric conversion element of the present invention, pinholes and cracks can be prevented from occurring in the perovskite layer formed on the adjacent layer. The conversion element can be easily manufactured.

It is sectional drawing of 1st embodiment of the solid junction type photoelectric conversion element of this invention. It is sectional drawing of 2nd embodiment of the solid junction type photoelectric conversion element of this invention. It is sectional drawing of 3rd embodiment of the solid junction type photoelectric conversion element of this invention. It is sectional drawing of 4th embodiment of the solid junction type photoelectric conversion element of this invention. It is sectional drawing of 5th embodiment of the solid junction type photoelectric conversion element of this invention. It is sectional drawing of 6th embodiment of the solid junction type photoelectric conversion element of this invention. It is sectional drawing of 7th embodiment of the solid junction type photoelectric conversion element of this invention. It is sectional drawing which shows the boundary of a perovskite layer and an adjacent layer in an example of the solid junction type photoelectric conversion element of this invention. It is sectional drawing which shows the boundary of a perovskite layer and an adjacent layer in an example of the solid junction type photoelectric conversion element of this invention. It is a graph which shows the relationship between Rz (Rz-a) of the solid junction type photoelectric conversion element produced in the Example, and the generation frequency of leak current. It is a graph which shows the relationship between the roughness ratio of Rz-a / Rz-b of the solid junction type photoelectric conversion element produced in the Example, and photoelectric conversion efficiency.

  Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments, but the present invention is not limited to such embodiments.

  In the present specification, “membrane” and “layer” are not distinguished unless otherwise specified. A solid junction type photoelectric conversion element may be simply referred to as a “photoelectric conversion element”, and an organic / inorganic perovskite compound may be simply referred to as a “perovskite compound”.

<< Solid-junction photoelectric conversion element >>
The solid junction photoelectric conversion element of the first aspect of the present invention is a solid junction photoelectric conversion element including a first conductive layer, a perovskite layer, and a second conductive layer in this order.
Other layers such as an anchor layer containing fine particles and an N-type semiconductor layer may be provided between the first conductive layer and the perovskite layer. The adjacent layer (first adjacent layer) adjacent to the perovskite layer on the first conductive layer side may be the first conductive layer or the other layers described above. The first conductive layer can function as an anode (an electrode through which electrons flow out to an external circuit).
Other layers such as an anchor layer containing fine particles and a P-type semiconductor layer may be provided between the perovskite layer and the second conductive layer. The adjacent layer (second adjacent layer) adjacent to the perovskite layer on the second conductive layer side may be the second conductive layer or the other layer described above. The second conductive layer can function as a cathode (an electrode through which electrons flow from an external circuit).

  The solid junction photoelectric conversion element according to the first aspect of the present invention includes at least a first conductive layer, a perovskite layer, and a second conductive layer in this order, and further includes an N-type layer between the first conductive layer and the perovskite layer. At least one of a semiconductor layer and an anchor layer is optionally provided, and a P-type semiconductor layer is optionally provided between the second conductive layer and the perovskite layer. The first conductive layer, the N-type semiconductor layer or the anchor layer is directly laminated on the first surface of the perovskite layer, and the second conductive layer or the P is stacked on the second surface of the perovskite layer. A type semiconductor layer is directly laminated. A first adjacent layer (the first conductive layer, the N-type semiconductor layer or the anchor layer) directly stacked on the first surface of the perovskite layer and a second layer of the perovskite layer; Among the second adjacent layers (the second conductive layer or the P-type semiconductor layer), the maximum height roughness (Rz) of the bonding surface in contact with the perovskite layer in at least one adjacent layer is 1 nm or more. Here, Rz is the sum of Rp and Rv, as will be described later.

  The perovskite layer is a layer formed by crystallizing or solidifying a perovskite compound, and is preferably a layer basically containing a perovskite compound as a main material except for a trace amount substance that can be doped.

  FIG. 8 illustrates a partial cross-sectional view in the thickness direction of the photoelectric conversion element according to the present invention. In this cross section, the boundary line between the perovskite layer and the arbitrary adjacent layer is a line obtained by tracing the fracture surface of the joint surface K between the perovskite layer and the arbitrary adjacent layer.

In the photoelectric conversion element according to the present invention, as illustrated in FIG. 8, the perovskite in at least one adjacent layer among the two adjacent layers (first adjacent layer and second adjacent layer) adjacent to both sides of the perovskite layer. The maximum height roughness (Rz) of the bonding surface K in contact with the layer is 1 nm or more.
Here, Rz is the sum of the peak height maximum value (Rp) and the valley depth maximum value (Rv) within the reference length (L) in the joint surface K. This Rz is synonymous with the maximum height roughness (Rz) defined in JIS B0601-2001 (ISO 4287: 1997), and is measured as follows based on the same standard. The reference length (L) is arbitrarily set within a range of, for example, 1 μm or more and 10 μm or less. However, when a large crack is generated in the perovskite layer, the reference length is measured so that a region excluding the crack is measured. (L) is set. The reference length (L) may be set as appropriate according to the crystal size of the perovskite compound as long as Rz at a plurality of locations can be measured (for example, 5 locations).
As a specific measuring method of Rz, a cross section cut in the thickness direction of the solid junction photoelectric conversion element to be measured is observed with a scanning electron microscope, the bonding surface K is specified by image processing, and the Rz is measured. The lengthening method is preferred. It is preferable to measure Rz at a plurality of locations (for example, 5 locations) with respect to the same measurement object and set the arithmetic average thereof to Rz.

When the Rz of the bonding surface K is 1 nm or more, it is possible to prevent the residual stress contained in the perovskite layer from being released when the photoelectric conversion element is used and causing pinholes and cracks.
As this mechanism, by making the adjacent layer bite into the perovskite layer at a plurality of locations, sliding in directions away from each other (direction along the joint surface K) is prevented by residual stress inside the perovskite layer. Conceivable. In addition, it is considered that the portion where the residual stress is concentrated, which leads to the slip, is reduced, or the residual stress inside the perovskite layer is dispersed.
The above residual stress may occur when a solution containing a perovskite compound is applied at the time of manufacturing a photoelectric conversion element, dried, and a coating film is formed or after it is formed.

  When Rz of the bonding surface K is 1 nm or more, the bonding area between the perovskite layer and the adjacent layer (surface area of the adjacent layer) is increased as compared with the case where Rz is less than 1 nm. Thereby, the efficiency of electron transport between the perovskite layer and the adjacent layer is increased, and the photoelectric conversion efficiency can be improved.

Rz is preferably 1 nm to 1000 nm, more preferably 1 nm to 500 nm, and even more preferably 5 nm to 200 nm from the viewpoint of preventing the occurrence of pinholes and cracks and improving the photoelectric conversion efficiency.
If it is at least the lower limit value, the above effect is further enhanced, and if it is not more than the upper limit value, the mechanical strength of the perovskite layer and / or the adjacent layer is weakened, or the unevenness of the joint surface K itself causes leakage. Can be prevented.
Rz may be larger than the thickness of the adjacent layer, but is preferably smaller than the thickness of the adjacent layer from the viewpoint of reducing the leak frequency and improving the photoelectric conversion efficiency.

FIG. 9 is a cross-sectional view of the photoelectric conversion element taken along the thickness direction, including the boundary between the perovskite layer and the adjacent layer.
In the photoelectric conversion element according to the present invention, the reference length (L) is taken on the horizontal side and the Rz (= Rp + Rv) is taken in a cross-sectional view including the joint surface K in the thickness direction of the perovskite layer (see FIG. 9). Of the rectangular area S (= L × Rz) taken along the vertical side, the occupancy rate of the adjacent layer is preferably 10 to 90%. Here, the occupation rate of the perovskite layer is 100%-(occupation rate of the adjacent layer).

  In FIG. 9, the area surrounded by the rectangle is represented by S, the occupied area of the perovskite layer is represented by s1, and the occupied area of the adjacent layer is represented by s2. Here, the square area S = (area s1 of the occupied region of the perovskite layer) + (area s2 of the occupied region of the adjacent layer).

The occupation ratio of the adjacent layer is preferably 10 to 90%, more preferably 10 to 70%, and still more preferably 30 to 70%.
If it is not less than the above lower limit value, the effect of preventing the occurrence of pinholes and cracks and improving the photoelectric conversion efficiency is further enhanced, and if it is not more than the above upper limit value, the mechanical strength of the adjacent layer can be sufficiently maintained. it can.
As a method for measuring the occupation ratio of the adjacent layer, the cross section cut in the thickness direction of the solid junction photoelectric conversion element to be measured is observed with a scanning electron microscope, the bonding surface K is specified by image processing, A method for obtaining the area s1 and the area s2 is preferable. It is preferable to measure the area s1 and the area s2 at a plurality of locations (for example, 5 locations) with respect to the same measurement object and set the arithmetic averages as the area s1 and the area s2, respectively.

Hereinafter, specific embodiments of the photoelectric conversion element will be illustrated with reference to the drawings.
[First embodiment]
FIG. 1 is a cross-sectional view of the photoelectric conversion element 10A cut in the thickness direction.
In the photoelectric conversion element 10 </ b> A illustrated in FIG. 1, the base material 4, the first conductive layer 1, the perovskite layer 3, and the second conductive layer 2 are sequentially stacked.
Rz (Rz-a) of the joint surface K (Ka) that contacts the perovskite layer 3 in the first conductive layer 1 that is the first adjacent layer is 1 nm or more. Concave and convex shapes having Rz (Rz-a) of 1 nm or more are formed on the bonding surface K (K-a).
The Rz (Rz-b) of the bonding surface K (Kb) in contact with the perovskite layer 3 in the second conductive layer 2 as the second adjacent layer is preferably 1 nm or more. The concavo-convex shape on the bonding surface Kb in the figure is omitted and not drawn.

[Second Embodiment]
FIG. 2 is a cross-sectional view of the photoelectric conversion element 10B cut in the thickness direction.
In the photoelectric conversion element 10B shown in FIG. 2, the base material 4, the first conductive layer 1, the anchor layer 5 containing fine particles, the perovskite layer 3, and the second conductive layer 2 are sequentially laminated.
Rz (Rz-a) of the joint surface K (Ka) in contact with the perovskite layer 3 in the anchor layer 5 as the first adjacent layer is 1 nm or more. Concave and convex shapes having Rz (Rz-a) of 1 nm or more are formed on the joint surface K (K-a).
The anchor layer 5 may be a dense film or a porous film. In the case of a porous film, a part of the perovskite layer 3 may be included in the pores. When a part of the perovskite layer 3 is included inside the porous anchor layer 5 and conduction between the perovskite layer 3 and the first conductive layer 1 is secured by the part, the fine particles constituting the anchor layer 5 are insulated. May be fine particles.
The Rz (Rz-b) of the bonding surface K (Kb) in contact with the perovskite layer 3 in the second conductive layer 2 as the second adjacent layer is preferably 1 nm or more. The concavo-convex shape on the bonding surface Kb in the figure is omitted and not drawn.

[Third embodiment]
FIG. 3 is a cross-sectional view of the photoelectric conversion element 10C cut in the thickness direction.
In the photoelectric conversion element 10 </ b> C illustrated in FIG. 3, the base material 4, the first conductive layer 1, the perovskite layer 3, and the second conductive layer 2 are sequentially stacked.
Rz (Rz-a) of the joint surface K (Ka) that contacts the perovskite layer 3 in the first conductive layer 1 that is the first adjacent layer is 1 nm or more. Concave and convex shapes having Rz (Rz-a) of 1 nm or more are formed on the joint surface K (K-a).
The Rz (Rz-b) of the bonding surface K (Kb) in contact with the perovskite layer 3 in the second conductive layer 2 as the second adjacent layer is preferably 1 nm or more. The concavo-convex shape on the bonding surface Kb in the figure is omitted and not drawn.
The joint surface J1 in contact with the first conductive layer 1 in the base material 4 has an uneven shape similar to the joint surface K (Ka), and the joint surface in contact with the first conductive layer 1 in the base material 4 The maximum height roughness (Rz ″) is set to 1 nm or more. Thereby, the adhesion between the first conductive layer 1 and the substrate 4 is improved.
Here, Rz ″ is the sum of the peak height maximum value (Rp) and valley depth maximum value (Rv) within the reference length (L) on the joint surface J1 of the base material 4. This Rz ″ is JIS. It is synonymous with the maximum height roughness (Rz) defined in B0601-2001, and is measured by the method described above based on the same standard.

[Fourth embodiment]
FIG. 4 is a cross-sectional view of the photoelectric conversion element 10D cut in the thickness direction.
In the photoelectric conversion element 10D shown in FIG. 4, the base material 4, the first conductive layer 1, the N-type semiconductor layer 6, the perovskite layer 3, the P-type semiconductor layer 7, and the second conductive layer 2 are sequentially laminated.
Rz (Rz-a) of the joint surface K (Ka) in contact with the perovskite layer 3 in the N-type semiconductor layer 6 as the first adjacent layer is 1 nm or more. Concave and convex shapes having Rz (Rz-a) of 1 nm or more are formed on the bonding surface K (Ka).
The N-type semiconductor layer 6 is made of a material different from that of the first conductive layer 1 and is formed of an N-type semiconductor. Since the N-type semiconductor layer 6 is provided, it is possible to promote that photoelectrons generated in the perovskite layer 3 flow into the N-type semiconductor layer 6 and flow toward the first conductive layer 1 side.
The P-type semiconductor layer 7 is made of a material different from that of the second conductive layer 2 and is formed of a P-type semiconductor. Since the P-type semiconductor layer 7 is provided, holes generated in the perovskite layer 3 can be promoted to flow into the P-type semiconductor layer 7 and to the second conductive layer 2 side.
Rz (Rz-b) of the bonding surface K (Kb) in contact with the perovskite layer 3 in the P-type semiconductor layer 7 as the second adjacent layer is preferably 1 nm or more. The concavo-convex shape on the bonding surface Kb in the figure is omitted and not drawn.

[Fifth embodiment]
FIG. 5 is a cross-sectional view of the photoelectric conversion element 10E cut in the thickness direction.
In the photoelectric conversion element 10E shown in FIG. 5, the base material 4, the first conductive layer 1, the N-type semiconductor layer 6, the anchor layer 5 containing fine particles, the perovskite layer 3, the P-type semiconductor layer 7 and the second conductive layer 2 are provided. They are laminated in order.
Rz (Rz-a) of the joint surface K (Ka) in contact with the perovskite layer 3 in the anchor layer 5 as the first adjacent layer is 1 nm or more. Concave and convex shapes having Rz (Rz-a) of 1 nm or more are formed on the joint surface K (K-a).
The anchor layer 5 may be a dense film or a porous film. In the case of a porous film, a part of the perovskite layer 3 may be included in the pores. When a part of the perovskite layer 3 is included in the porous anchor layer 5 and conduction between the perovskite layer 3 and the N-type semiconductor layer 6 is secured by the part, the fine particles constituting the anchor layer 5 are insulated. May be fine particles.
The N-type semiconductor layer 6 is made of a material different from that of the first conductive layer 1, the P-type semiconductor layer 7 is made of a material different from that of the second conductive layer 2, and the role of each semiconductor layer is the same as in the fourth embodiment.
Rz (Rz-b) of the bonding surface K (Kb) in contact with the perovskite layer 3 in the P-type semiconductor layer 7 as the second adjacent layer is preferably 1 nm or more. The concavo-convex shape on the bonding surface Kb in the figure is omitted and not drawn.

[Sixth embodiment]
FIG. 6 is a cross-sectional view of the photoelectric conversion element 10F cut in the thickness direction.
In the photoelectric conversion element 10 </ b> F illustrated in FIG. 6, the base material 4, the first conductive layer 1, the N-type semiconductor layer 6, the perovskite layer 3, the P-type semiconductor layer 7, and the second conductive layer 2 are sequentially stacked.
Rz (Rz-a) of the joint surface K (Ka) in contact with the perovskite layer 3 in the N-type semiconductor layer 6 as the first adjacent layer is 1 nm or more. Concave and convex shapes having Rz (Rz-a) of 1 nm or more are formed on the joint surface K (K-a).
The N-type semiconductor layer 6 is made of a material different from that of the first conductive layer 1, the P-type semiconductor layer 7 is made of a material different from that of the second conductive layer 2, and the role of each semiconductor layer is the same as in the fourth embodiment.
Rz (Rz-b) of the bonding surface K (Kb) in contact with the perovskite layer 3 in the P-type semiconductor layer 7 as the second adjacent layer is preferably 1 nm or more. The concavo-convex shape on the bonding surface Kb in the figure is omitted and not drawn.

The joint surface J1 in contact with the N-type semiconductor layer 6 in the first conductive layer 1 has an uneven shape similar to that of the joint surface K. The maximum of the joint surface in contact with the N-type semiconductor layer 6 in the first conductive layer 1 The height roughness (Rz ′) is 1 nm or more. Thereby, the adhesiveness between the N-type semiconductor layer 6 and the first conductive layer 1 is improved, and the photoelectric conversion efficiency can be improved by further increasing the junction area.
Here, Rz ′ is the sum of the peak height maximum value (Rp) and the valley depth maximum value (Rv) within the reference length (L) in the joint surface J1 of the first conductive layer 1. This Rz ′ is synonymous with the maximum height roughness (Rz) defined in JIS B0601-2001, and is measured by the method described above in accordance with the same standard.

[Seventh embodiment]
FIG. 7 is a cross-sectional view of the photoelectric conversion element 10G cut in the thickness direction.
In the photoelectric conversion element 10G shown in FIG. 7, the base material 4, the first conductive layer 1, the N-type semiconductor layer 6, the perovskite layer 3, the P-type semiconductor layer 7, and the second conductive layer 2 are sequentially laminated.
Rz (Rz-a) of the joint surface K (Ka) in contact with the perovskite layer 3 in the N-type semiconductor layer 6 as the first adjacent layer is 1 nm or more. Concave and convex shapes having Rz (Rz-a) of 1 nm or more are formed on the joint surface K (K-a).
The N-type semiconductor layer 6 is made of a material different from that of the first conductive layer 1, the P-type semiconductor layer 7 is made of a material different from that of the second conductive layer 2, and the role of each semiconductor layer is the same as in the fourth embodiment.
Rz (Rz-b) of the bonding surface K (Kb) in contact with the perovskite layer 3 in the P-type semiconductor layer 7 as the second adjacent layer is preferably 1 nm or more. The concavo-convex shape on the bonding surface Kb in the figure is omitted and not drawn.

  The joint surface J1 in contact with the N-type semiconductor layer 6 in the first conductive layer 1 has an uneven shape similar to that of the joint surface K. Rz of the joint surface in contact with the N-type semiconductor layer 6 in the first conductive layer 1 'Is 1 nm or more. Thereby, the adhesiveness between the N-type semiconductor layer 6 and the first conductive layer 1 is improved, and the photoelectric conversion efficiency can be improved by further increasing the junction area.

The joint surface J2 in contact with the first conductive layer 1 in the base material 4 has an uneven shape similar to that of the joint surface J1, and Rz ″ of the joint surface in contact with the first conductive layer 1 in the base material 4 is 1 nm or more. Thereby, the adhesiveness of the 1st conductive layer 1 and the base material 4 is improving.
The description of Rz ′ and Rz ″ is the same as the description of Rz ′ and Rz ″ described above, and will be omitted.

  Although the photoelectric conversion elements of the first embodiment to the seventh embodiment exemplified above include the base material 4, the layers other than the base material 4, for example, the first conductive layer 1, are sufficiently thick and self-supporting. When it has, it is good also as a structure which excluded the base material 4. FIG.

  From the viewpoint of improving the production yield and photoelectric conversion efficiency of the photoelectric conversion device according to the present invention, the roughness ratio represented by (Rz-a) / (Rz-b) is preferably 0.1 or more and 1000 or less. 2 or more and 100 or less are more preferable, 0.3 or more and 80 or less are more preferable, 0.5 or more and 50 or less are more preferable, 0.8 or more and 40 or less are still more preferable, and 1.0 or more and 30 or less are particularly preferable. 2.0 to 20 is most preferable. Rz (Rz-a) of the bonding surface K (Ka) in which the adjacent layer (for example, the first adjacent layer) formed earlier in manufacturing the photoelectric conversion element is in contact with the perovskite layer 3 is formed later in manufacturing. The adjacent layer (for example, the second adjacent layer) is preferably larger than Rz (Rz-b) of the bonding surface K (Kb) in contact with the perovskite layer 3.

  In the photoelectric conversion device according to the present invention, the total roughness obtained by the addition of (Rz−a) + (Rz−b) is preferably smaller than the thickness of the perovskite layer, and the thickness of the perovskite layer Is more preferably 80% or less, and still more preferably 60% or less of the thickness of the perovskite layer.

Hereinafter, the material and thickness of each layer will be described.
The following method is preferable as a method for measuring the thickness of each layer. The cross section cut in the thickness direction of the solid junction photoelectric conversion element to be measured is observed with a scanning electron microscope, the boundary between each layer is specified by image processing, and 10 points randomly selected for each layer are measured. The thickness is measured, and the arithmetic average is taken as the thickness of each layer.

(First conductive layer 1)
The material of the first conductive layer 1 is not particularly limited as long as it is a conductive layer, and a material capable of forming a transparent layer is preferable. For example, tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony Metal oxides such as doped tin oxide (ATO), tin dioxide (SnO ₂ ), and zinc oxide (ZnO) are suitable. In addition, one or more metals selected from the group consisting of gold, silver, copper, aluminum, tungsten, nickel, and chromium, carbon materials, conductive polymer materials, semiconductor materials that can be formed by a sol-gel method, etc. Applicable.
The type of material constituting the first conductive layer 1 may be one type or two or more types.
The thickness of the 1st conductive layer 1 is not specifically limited, For example, 100 nm-500 nm are preferable.
When the first conductive layer 1 forms the bonding surface K with Rz (Rz-a) 1 nm or more or Rz′1 nm or more, the thickness is preferably 10 nm or more.

(Second conductive layer 2)
The description of the material and thickness of the second conductive layer 2 is the same as the description of the material and thickness of the first conductive layer 1, and will be omitted.
In addition, from the viewpoint of irradiating light to the perovskite layer 3 that is the power generation layer of the photoelectric conversion element, at least one of the first conductive layer 1 and the second conductive layer 2 is preferably transparent.

(Perovskite layer 3)
The perovskite layer 3 is a layer containing a perovskite compound, and may be formed of only a perovskite compound or may contain other substances.
The type of the perovskite compound is not particularly limited, and a perovskite compound used in a known solar cell is applicable, has a crystal structure, and exhibits light absorption by bandgap excitation in the same manner as a typical compound semiconductor. Is preferred. For example, CH ₃ NH ₃ PbI ₃ , which is a known perovskite compound, is known to have an extinction coefficient (cm ⁻¹ ) per unit thickness that is an order of magnitude higher than that of a sensitizing dye of a dye-sensitized solar cell. Yes.

The thickness of the perovskite layer 3 is, for example, preferably 10 nm to 10 μm, more preferably 50 nm to 1 μm, still more preferably 100 nm to 500 nm, and particularly preferably 300 nm to 500 nm.
When it is at least the lower limit of the above range, the light absorption efficiency in the perovskite layer 3 is increased, and a more excellent photoelectric conversion efficiency is obtained.
If it is not more than the upper limit of the above range, the efficiency with which the photoelectrons generated in the perovskite layer 3 reach the first conductive layer 1 increases, and a more excellent photoelectric conversion efficiency is obtained.

(Substrate 4)
The kind in particular of the base material 4 is not restrict | limited, For example, the transparent base material used for the photoelectrode of the conventional solar cell is mentioned. Examples of the transparent substrate include a substrate made of glass or synthetic resin, a flexible film made of synthetic resin, and the like.

  When the material of the transparent substrate is a synthetic resin, examples of the synthetic resin include polyacrylic resin, polycarbonate resin, polyester resin, polyimide resin, polystyrene resin, polyvinyl chloride resin, and polyamide resin. Among these, polyester resins, particularly polyethylene naphthalate (PEN) and polyethylene terephthalate (PET) are preferable from the viewpoint of producing a thin, light and flexible photoelectric conversion element.

  The combination of the thickness and material of the base material 4 is not particularly limited, and examples thereof include a glass substrate having a thickness of 1 mm to 10 mm and a resin film having a thickness of 0.01 mm to 3 mm.

(Anchor layer 5)
The anchor layer 5 is a layer formed by bonding or binding a large number of fine particles to each other, and may be a dense film or a porous film.

  The material of the fine particles is not particularly limited, and a conductive material is preferable. For example, a metal oxide such as tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO); selected from the group consisting of gold, silver, copper, aluminum, tungsten, nickel and chromium Any one or more kinds of metals; carbon materials; conductive polymer materials, and the like can be given.

An N-type semiconductor can also be used as the material for the fine particles. For example, N-type oxide semiconductors excellent in electron conductivity such as titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO, SnO ₂ ), IGZO, strontium titanate (SrTiO ₃ ), and the like can be given. .

In the case where the anchor layer 5 is a porous film, an insulator can be applied as the material of the fine particles, and examples thereof include oxides that constitute an insulating layer of a conventional semiconductor device. Specific examples include zirconium dioxide, silicon dioxide, aluminum oxide (AlO, Al ₂ O ₃ ), magnesium oxide (MgO), nickel oxide (NiO), and the like. Of these, aluminum (III) (Al ₂ O ₃ ) is particularly preferable from the viewpoint of forming a suitable Rz.

The average particle diameter of the fine particles constituting the anchor layer 5 is not particularly limited, and is preferably 1 to 500 nm, more preferably 5 to 300 nm, and still more preferably 10 to 500 nm, for example. Within these suitable ranges, it is possible to easily form a concavo-convex shape with Rz (Rz-a) of 1 nm or more.
Here, the average particle diameter is an “arithmetic average value of particle diameters” defined in JIS Z 8901: 2006 “Test Powder and Test Particles”. 3. “Measurement Method of Average Particle Diameter of Test Particle 1” It is a value obtained based on transmission electron microscopy.

The kind of fine particles constituting the anchor layer 5 may be one kind or two or more kinds.
The thickness of the anchor layer 5 is not particularly limited, and is preferably 10 nm to 300 nm, for example. When the anchor layer 5 forms the bonding surface K with Rz (Rz-a) 1 nm or more, the thickness is preferably 10 nm or more.

(N-type semiconductor layer 6)
The N-type semiconductor layer 6 may be a dense film or a porous film. However, considering the role of the N-type semiconductor layer 6 to prevent backflow of electrons (generation of reverse current), the N-type semiconductor layer 6 is dense. A membrane is preferred.
When the N-type semiconductor layer 6 is a porous film, the perovskite layer 3 is allowed to be partly contained in the pores. If this is allowed, there is a concern that the perovskite layer 3 and the first conductive layer 1 are directly connected to each other, so that the N-type semiconductor layer 6 cannot fulfill the above role. If the N-type semiconductor layer 6 is a dense film, there is no concern about this.

The material of the N-type semiconductor layer 6 is not particularly limited. For example, electron conduction such as titanium oxide (TiO ₂ ), zinc oxide (ZnO), tin oxide (SnO, SnO ₂ ), IGZO, strontium titanate (SrTiO ₃ ), etc. An N-type oxide semiconductor having excellent properties can be exemplified.
The type of the N-type semiconductor constituting the N-type semiconductor layer 6 may be one type or two or more types.
The material of the N-type semiconductor layer 6 and the material of the first conductive layer 1 are preferably different from each other.
The material of the N-type semiconductor layer 6 and the material of the anchor layer 5 are preferably different from each other.

  The thickness of the N-type semiconductor layer 6 is not specifically limited, For example, about 1 nm-1 micrometer are mentioned. When the thickness is 1 nm or more, the above role is sufficiently fulfilled, and when the thickness is 1 μm or less, the internal resistance can be kept low. When the N-type semiconductor layer 6 forms a bonding surface K (K-a) with Rz (Rz-a) of 1 nm or more, the thickness of the N-type semiconductor layer 6 is preferably 10 nm or more, and more preferably 100 nm or more. The thickness of the N-type semiconductor layer 6 is preferably larger than the Rz-a value, and more preferably twice or more the Rz-a value.

(P-type semiconductor layer 7)
The type of the P-type semiconductor that is the material of the P-type semiconductor layer 7 is not particularly limited, and may be an organic material or an inorganic material.
For example, a P-type semiconductor for a hole transport layer of a known solar cell can be applied. Examples of the organic material include 2,2 ′, 7,7′-tetrakis (N, N-di-p-methoxyphenilamine) -9,9′-spirobifluorene (abbreviation: spiro-OMeTAD), Poly (3-hexylthiophene) (Abbreviation: P3HT), polytriarylamine (abbreviation: PTAA), and the like.
Examples of the inorganic material include copper compounds such as CuI, CuSCN, CuO, and Cu ₂ O, and nickel compounds such as NiO.
There may be one type of P-type semiconductor constituting the P-type semiconductor layer 7 or two or more types.
The material of the P-type semiconductor layer 7 and the material of the second conductive layer 2 are preferably different from each other.

The thickness of the P-type semiconductor layer 7 is not specifically limited, For example, 1 nm-1000 nm are preferable, 5 nm-500 nm are more preferable, 30 nm-500 nm are more preferable, 50 nm-200 nm are especially preferable.
High electromotive force can be obtained as it is more than the lower limit of the said range.
If it is not more than the upper limit of the above range, the internal resistance can be further reduced.
When the P-type semiconductor layer 7 forms a bonding surface K (Kb) with Rz (Rz-b) 1 nm or more, the thickness of the P-type semiconductor layer 7 is preferably 10 nm or more, more preferably 50 nm or more, and 100 nm or more. Further preferred. The thickness of the P-type semiconductor layer 7 is preferably larger than the Rz-b value, and more preferably twice or more the Rz-b value.

<< Power generation of solid junction photoelectric conversion element >>
When the perovskite layer 3 absorbs light, photoelectrons and holes are generated in the layer. When the anchor layer 5 and the N-type semiconductor layer 6 are provided, the photoelectrons move to the working electrode (positive electrode) formed by the first conductive layer 1 through these. On the other hand, when the P-type semiconductor layer 7 is provided, the holes move to the counter electrode (negative electrode) formed by the second conductive layer 2 through the P-type semiconductor layer 7.
The current generated by the photoelectric conversion element is taken out to an external circuit through each extraction electrode connected to the first conductive layer 1 and the second conductive layer 2.

<< Production Method of Solid Junction Photoelectric Conversion Element >>
The 2nd aspect of this invention is a manufacturing method of the solid junction type photoelectric conversion element provided with the perovskite layer and the adjacent layer which has a joint surface which contact | connects this. This manufacturing method includes a step of applying a solution containing a compound that forms the perovskite layer to the bonding surface of the adjacent layer to form a coating film (coating film forming step), and drying the coating film. Forming a perovskite layer (curing step).
The maximum height roughness (Rz) of the bonding surface is 1 nm or more, and the Rz is a peak height maximum value (Rp) and a valley depth maximum value (Rv) within a reference length (L) in the bonding surface. Is the sum of This Rz is synonymous with the maximum height roughness (Rz) defined in JIS B0601-2001, and is measured by the method described above according to the same standard.

In the curing step, a solution containing a perovskite compound is applied and dried, and the coating film gradually shrinks to form a cured or crystallized perovskite layer. At this time, stress in a direction away from each other (direction along the bonding surface) is generated inside the perovskite layer which is gradually formed while the coating film contracts.
For example, when manufacturing the photoelectric conversion element 10 </ b> A of FIG. 1, consider a situation in which the perovskite layer 3 is formed while the coating film gradually contracts on the bonding surface K of the first conductive layer 1. In this situation, in the cross-sectional view of FIG. 1, the left half area and the right half area of the coating film (perovskite layer 3) are aggregated independently of each other, and a crack (or pinhole) is generated at the center. Stress is generated to form the perovskite layer 3 separated into a half and a right half. This stress naturally occurs with drying due to physical properties such as the surface tension of the solution constituting the coating film.

However, even if the above stress occurs, in the manufacturing method according to the present invention, an uneven shape is formed on the joint surface K, and the Rz of the joint surface K is 1 nm or more. The perovskite layer 3 that does not generate holes and hardly generates a leak current can be formed.
As this mechanism, the uneven shape formed on the joint surface functions as a physical resistance to the stress, and thus it is considered that the coating film is prevented from fluidizing or fragmenting due to the stress.

In the curing step, drying the coating film means removing the solvent to such an extent that the solvent contained in the coating film is volatilized and a cured perovskite layer 3 is obtained.
The smaller the amount of the solvent remaining in the perovskite layer 3, the better. The content of the residual solvent with respect to the total mass (100%) of the perovskite layer 3 is preferably 0.1% or less, and more preferably 0.01% or less.

Hereinafter, a method for forming each layer of the solid junction photoelectric conversion element according to the present invention and a surface roughening method (method for forming an uneven shape) with Rz of 1 nm or more will be described.
<Preparation of base material 4>
The base material 4 can be produced by a conventional method, and a commercially available product may be used.
As a method for roughening the substrate 4, for example, a known nanoimprint method may be mentioned.
Examples of the concavo-convex shape to be formed include a line pattern, a dot pattern, a hole pattern, and the like.

<Formation of the first conductive layer 1>
The method for forming the first conductive layer 1 on the surface of the substrate 4 is not particularly limited, and for example, a known film forming method such as a sputtering method or a vapor deposition method can be applied. A known sol-gel method in which a dispersion containing a semiconductor precursor is applied to the surface of the substrate 4 to form a conductive layer made of a semiconductor can also be applied.

As a method of roughening the first conductive layer 1, for example, a method of mechanically polishing the surface of the first conductive layer 1 with a grinder, sandpaper, buff or the like; And a method of chemically forming irregularities by bringing them into contact; a method of physically forming irregularities by irradiating the surface of the first conductive layer 1 with a laser; and the like.
When the uneven shape is previously formed on the surface of the substrate 4, the first conductive layer 1 having the uneven shape following the uneven shape of the substrate 4 is formed by forming the first conductive layer 1 on the surface. can do.

<Formation of N-type Semiconductor Layer 6>
The method for forming the N-type semiconductor layer 6 on the first conductive layer 1 is not particularly limited. For example, a sputtering method, a vapor deposition method, or a dispersion containing an N-type semiconductor precursor is applied to the surface of the first conductive layer 1. Examples thereof include a sol-gel method to be applied.

Examples of N-type semiconductor precursors include titanium tetrachloride (TiCl ₄ ), peroxotitanic acid (PTA), titanium alkoxide such as titanium ethoxide and titanium isopropoxide (TTIP), zinc alkoxide, alkoxysilane, and zirconium. Examples thereof include metal alkoxides such as alkoxides.

Examples of the method for roughening the N-type semiconductor layer 6 include the same method as the method for roughening the first conductive layer 1 described above.
When an uneven shape is formed in advance on the surface of the first conductive layer 1, an N-type semiconductor having an uneven shape following the uneven shape of the first conductive layer 1 by forming an N-type semiconductor layer 6 on the surface. Layer 6 can be formed.

<Formation of anchor layer 5>
The method for forming the anchor layer 5 containing fine particles on the first conductive layer 1 or the N-type semiconductor layer 6 is not particularly limited. For example, a semiconductor layer carrying a sensitizing dye of a conventional dye-sensitized solar cell is used. The forming method can be applied.
Specifically, for example, a slurry containing fine particles made of a conductor or an N-type semiconductor is applied to the surface of the first conductive layer 1 or the N-type semiconductor layer 6 by a spin coat method, and dried, thereby anchoring the fine particles. Layer 5 can be formed.
By spraying the fine particles on the surface of the first conductive layer 1 or the N-type semiconductor layer 6, the anchor layer 5 of a porous film or a dense film (non-porous film) made of the fine particles can be formed.

  As the fine particle spraying method, known methods can be applied, for example, aerosol deposition method (AD method), electrostatic fine particle coating method (electrostatic spray method) in which fine particles are accelerated by electrostatic force, cold spray method, etc. Is mentioned.

Examples of the method for forming the uneven shape on the surface of the anchor layer 5 include the same method as the method for roughening the first conductive layer 1 described above.
A method of appropriately adjusting the mixing ratio of the large-sized particles and the small-sized particles by setting the particle size distribution of the fine particles contained in the slurry as a bimodal distribution or a multimodal distribution.
Examples of the fine particle spraying include a method of appropriately adjusting the sweep speed of the spray nozzle, the spray speed, the mixing ratio of the sprayed powder and the carrier gas (sprayed powder density), and the like.

<Formation of perovskite layer 3>
As a method for forming the perovskite layer 3 on the adjacent layer (for example, the first conductive layer 1, the anchor layer 5 or the N-type semiconductor layer 6), for example, a perovskite compound or a raw material solution in which a perovskite compound precursor is dissolved is used. There is a method in which a perovskite layer is formed by applying to the surface of the adjacent layer, forming a coating film of a solution having a desired thickness, and drying a solvent contained in the coating film.

  When the adjacent layer is a porous layer, the raw material solution penetrates into the pores of the adjacent layer, and a part of the perovskite layer 3 is formed inside the adjacent layer.

  The method for applying the raw material solution to the surface of the adjacent layer is not particularly limited. For example, a known method such as a gravure coating method, a bar coating method, a printing method, a spray method, a spin coating method, a dip method, or a die coating method is applied. it can.

  The concentration of the raw material in the raw material solution is not particularly limited, and is preferably a concentration that is sufficiently dissolved or dispersed and exhibits a viscosity that allows the raw material solution to be coated with a uniform thickness by the coating method.

  The thickness of the coating film immediately after being formed by applying the raw material solution to the adjacent layer (before drying) is in a range thicker than the Rz value of the bonding surface of the adjacent layer, for example, in the range of 10 nm to 10 μm. It is preferable to apply.

The method for drying the coating film is not particularly limited, and methods such as natural drying, reduced pressure drying, and hot air drying can be applied.
The drying temperature of the coating film may be a temperature at which crystallization (curing of the coating film) of the perovskite compound proceeds sufficiently, and examples thereof include a range of 40 to 150 ° C.
As the degree of the drying treatment, it is preferable to dry until the content of the solvent with respect to the total mass (100%) of the cured perovskite layer is 0.1% or less, and it is dried until it is 0.01% or less. Is more preferable.
As a method for drying the coating film, a method of naturally drying at a room temperature of 10 to 40 ° C. or a method of drying by gently blowing warm air of about 35 to 70 ° C. on the application surface of the raw material solution is preferable. Thereby, the relationship that Rz-a of the 1st adjacent layer formed previously is larger than Rz-b of the 2nd adjacent layer formed later can be acquired easily.

  After applying the raw material solution to the adjacent layer, before the coated surface is completely dried, a poor solvent that hardly dissolves the perovskite compound is dropped on the coated surface, and the poor solvent is added onto the coated surface. After diffusion, the perovskite layer is formed by a method of naturally drying at a room temperature of 10 to 40 ° C. or a method of gently blowing a hot air of about 40 to 70 ° C. on the coated surface of the raw material solution to dry it. Is more preferable. Thereby, the relationship of Rz-a> Rz-b can be obtained more easily.

  The poor solvent solubility parameter (δ, SP value) is preferably 8.5 or more, more preferably 9.0 or more, and even more preferably 9.5 or more. As an indication of the upper limit of the SP value, for example, 12.0 can be mentioned.

The perovskite compound is not particularly limited as long as it can generate an electromotive force by light absorption, and a known perovskite compound is applicable. Among these, perovskite-type crystals can be formed, and the following composition formula (1) having an organic component and an inorganic component in a single compound:
ABX ₃ (1)
The perovskite compound represented by these is preferable.

  In the composition formula (1), A represents an organic cation, B represents a metal cation, and X represents a halogen ion. In the perovskite crystal structure, the B site can take octahedral coordination with the X site. It is considered that the metal cation at the B site and the atomic orbital of the halogen ion at the X site are mixed to form a valence band and a conduction band related to photoelectric conversion.

The metal constituting the metal cation represented by B in the composition formula (1) is not particularly limited, and examples thereof include Cu, Ni, Mn, Fe, Co, Pd, Ge, Sn, Pb, and Eu. Among these, Pb and Sn are preferable because they can easily form a highly conductive band by hybridization with the atomic orbitals of halogen ions at the X site.
The metal cation constituting the B site may be one type or two or more types.

The halogen constituting the halogen ion represented by X in the composition formula (1) is not particularly limited, and examples thereof include F, Cl, Br, and I. Among these, Cl, Br, and I are preferable because they can easily form a highly conductive band by a hybrid orbital with a metal cation at the B site.
There may be one kind of halogen ion constituting the X site, or two or more kinds.

The organic group constituting the organic cation represented by A in the composition formula (1) is not particularly limited, and examples thereof include alkylammonium derivatives and formamidinium derivatives.
The organic cation constituting the A site may be one type or two or more types.

  Examples of the alkylammonium derivatives include, for example, methylammonium, dimethylammonium, trimethylammonium, ethylammonium, propylammonium, isopropylammonium, tert-butylammonium, pentylammonium, hexylammonium, octylammonium, phenylammonium and the like. Primary or secondary ammonium having an alkyl group. Of these, methylammonium, which can easily obtain perovskite crystals, is preferred.

  Examples of the formamidinium derivative include formamidinium, methylformamidinium, dimethylformamidinium, trimethylformamidinium, and tetramethylformamidinium. Of these, formamidinium is preferred because it can easily obtain a perovskite crystal.

As a suitable perovskite compound represented by the composition formula (1), for example, CH ₃ NH ₃ PbI ₃ , CH ₃ NH ₃ PbI _3-h Cl _h (h represents 0 to ₃ ), CH ₃ NH ₃ PbI _{The following} composition formula (2) such as _3-j Br _j (j represents 0 to 3):
RNH ₃ PbX ₃ (2)
The alkylamino lead halide represented by these is mentioned. In the composition formula (2), R represents an alkyl group, and X represents a halogen ion. Since the perovskite compound having this composition formula has a wide absorption wavelength range and can absorb a wide wavelength range of sunlight, excellent photoelectric conversion efficiency can be obtained.

  The alkyl group represented by R in the composition formula (2) is preferably a linear, branched or cyclic saturated or unsaturated alkyl group having 1 to 6 carbon atoms. It is more preferably a chain saturated alkyl group, and further preferably a methyl group, an ethyl group, or an n-propyl group. With these preferable alkyl groups, perovskite crystals can be easily obtained.

In the formation of the perovskite layer 3, examples of the precursor contained in the raw material solution include the halide (BX) containing the B site metal ion and the X site halogen ion described above, and the A site organic described above. And halide (AX) containing a cation and a halogen ion at the X site.
A single raw material solution containing halide (AX) and halide (BX) may be applied to the adjacent layer, or two raw material solutions containing each halide individually may be applied in turn to the adjacent layer. You may apply to.

  The solvent of the raw material solution is not particularly limited as long as it dissolves or disperses the raw material and does not damage the adjacent layer. For example, ester, ketone, ether, alcohol, glycol ether, amide, nitrile, carbonate, halogenated Examples thereof include hydrocarbons, hydrocarbons, sulfones, sulfoxides, formamides and the like.

  As an example, by dissolving a halogenated alkylamine and a lead halide in a mixed solvent of γ-butyrolactone (GBL) and dimethyl sulfoxide (DMSO), and applying the solution to the adjacent layer and drying, the composition formula (2 A perovskite crystal composed of a perovskite compound represented by Furthermore, as described in Non-Patent Document 2, after applying a solvent miscible with GBL or DMSO, such as toluene or chloroform, on the perovskite crystal, annealing is performed at about 100 ° C. You may add the process to do. This additional treatment may improve crystal stability and increase photoelectric conversion efficiency.

<Formation of P-type semiconductor layer 7>
The method for forming the P-type semiconductor layer 7 on the perovskite layer 3 is not particularly limited. For example, a solution in which the P-type semiconductor is dissolved or dispersed in a solvent that hardly dissolves the perovskite compound constituting the perovskite layer 3 is prepared. A method of obtaining the P-type semiconductor layer 7 by applying this solution to the surface of the perovskite layer 3 and drying it is mentioned.

<Formation of second conductive layer 2>
The method for forming the second conductive layer 2 on the perovskite layer 3 or the P-type semiconductor layer 7 is not particularly limited, and for example, the method for forming the first conductive layer 1 described above can be applied.

  The photoelectric conversion element in which the base material 4, the first conductive layer 1, the N-type semiconductor layer 6, the anchor layer 5, the perovskite layer 3, the P-type semiconductor layer 7, and the second conductive layer 2 are laminated in this order through the above steps. Can be manufactured.

  The method for sequentially laminating each layer from the first conductive layer 1 to the second conductive layer 2 has been described above. In the manufacturing method of the photoelectric conversion element concerning this invention, it is not restricted to the said order, You may employ | adopt the method of laminating | stacking each layer sequentially from the 2nd conductive layer 2 toward the 1st conductive layer 1. FIG.

[Example 1]
A transparent resin substrate (PEN substrate) having a transparent conductive layer (first conductive layer) made of ITO formed on the surface thereof was prepared. Etch unnecessary parts of this first conductive layer with hydrochloric acid, eliminating the possibility of unnecessary parts of the first conductive layer unintentionally coming into contact with other conductive members and causing short circuits or leakage currents. did.
Next, the surface of the ITO was roughened by rubbing the buff.
Subsequently, a DMF solution in which 1 M CH ₃ NH ₃ I and PbI ₂ were dissolved was spin-coated on the substrate, and dried by heating at 100 ° C. for 60 minutes, thereby forming a 300 nm thick perovskite layer (power generation layer). Furthermore, a second conductive layer made of an Au film having a thickness of 100 nm was formed on the perovskite layer by physical vapor deposition to produce a solid junction photoelectric conversion element.

The cross section of this element is observed with an SEM, the ITO layer and the perovskite layer are distinguished by contrast, and the maximum peak height within the reference length (L) of 1 μm in the horizontal direction along the joint surface of the ITO layer and the perovskite layer. Rz-a, which is the sum of (Rp) and the maximum valley depth (Rv), was measured at a plurality of locations (5 locations). The Rz-a values were all 4 to 12 nm, and the average value of Rz-a was 8 nm.
The cross section is observed with an SEM, the perovskite layer and the Au film are distinguished by contrast, and the maximum peak height (Rp) within the reference length (L) of 1 μm in the horizontal direction along the bonding surface between the perovskite layer and the Au film. ) And the maximum valley depth (Rv), Rz-b was measured at a plurality of locations (5 locations). The average value of Rz-b was 268 nm.
From the above measurement, Rz-a average value / Rz-b average value = 0.03.

  About the 20 solid junction type photoelectric conversion elements manufactured by the above method, the frequency (leakage frequency) at which leakage current occurs was evaluated by the following method. As a result, 15 pieces passed and 5 pieces (25%) failed.

  The leakage frequency of each photoelectric conversion element was evaluated by measuring the current-voltage characteristics in the dark state with a source meter and measuring the parallel resistance Rsh. Here, Rsh in the dark state is defined as | the gradient with respect to the voltage of current | near | 0V | = | the displacement of voltage | / | the displacement of current |. In this definition, it means that the smaller the absolute value of Rsh, the easier the leak current flows. Therefore, a photoelectric conversion element having an absolute value of Rsh of 1000 or less was evaluated as a defective product in which leakage current occurred.

A power source (manufactured by KEITHLEY, 236 model) is connected between the electrodes of the 20 solid-junction photoelectric conversion elements, and photoelectric conversion efficiency is obtained using a single light source type solar simulator (manufactured by Yamashita Denso Co., Ltd.) having an intensity of 100 mW / cm ^2. Was measured. The arithmetic average of these measured values was obtained as the average photoelectric conversion efficiency (average efficiency).
The results are shown in Table 1.

[Example 2]
On the etched ITO in the same manner as in Example 1, a dispersion liquid in which 20% by weight of ITO nanoparticles having a particle diameter of 20 nm is dispersed in ethanol is applied by spin coating to form an anchor layer made of ITO nanoparticles having a thickness of 150 nm. did. Thereafter, in the same manner as in Example 1, a perovskite layer and a second conductive layer were formed, and a solid junction photoelectric conversion element was produced and evaluated.

[Example 3]
On the etched ITO in the same manner as in Example 1, a dispersion obtained by dispersing 20 wt% of TiO ₂ nanoparticles having a particle size of 15 nm in ethanol was applied by spin coating, and an anchor layer made of TiO ₂ nanoparticles having a thickness of 150 nm. Formed. Thereafter, in the same manner as in Example 1, a perovskite layer and a second conductive layer were formed, and a solid junction photoelectric conversion element was produced and evaluated.

[Example 4]
A 50 nm-thick TiO ₂ film (N-type semiconductor layer) was formed on the etched ITO in the same manner as in Example 1 by sputtering. Next, the surface was roughened by rubbing a buff on the surface of the TiO ₂ film.
Subsequently, a perovskite layer was formed in the same manner as in Example 1, and then a chlorobenzene solution in which 65 mM spiro-OMeTAD was dissolved was spin-coated to form a P-type semiconductor layer having a thickness of 100 nm. A second conductive layer made of an Au film having a thickness of 100 nm was formed on the P-type semiconductor layer to produce a solid junction photoelectric conversion element. This was evaluated in the same manner as in Example 1.

[Example 5]
A 50 nm thick TiO ₂ film (N-type semiconductor layer) was formed on the ITO etched by the same method as in Example 1 by sputtering. Subsequently, a dispersion liquid in which 20 wt% of TiO ₂ nanoparticles having a particle diameter of 15 nm was dispersed in ethanol was applied by a spin coating method to form an anchor layer having a thickness of 150 nm made of TiO ₂ nanoparticles. Subsequently, a perovskite layer, a P-type semiconductor layer, and a second conductive layer were formed in the same manner as in Example 4, and a solid junction photoelectric conversion element was produced and evaluated.

[Example 6]
A 50 nm thick TiO ₂ film (N-type semiconductor layer) was formed on the ITO etched by the same method as in Example 1 by sputtering. Next, a dispersion liquid in which 20 wt% of Al ₂ O ₃ nanoparticles having a particle diameter of 20 nm was dispersed in ethanol was applied by a spin coating method to form an anchor layer having a thickness of 150 nm made of Al ₂ O ₃ nanoparticles. Subsequently, a perovskite layer, a P-type semiconductor layer, and a second conductive layer were formed in the same manner as in Example 4 to produce and evaluate a solid junction photoelectric conversion element.

[Example 7]
The surface was roughened by rubbing a buff on the etched ITO surface in the same manner as in Example 1. Next, a TiO ₂ film (N-type semiconductor film) having a thickness of 50 nm was formed by sputtering. Irregularities reflecting the irregularities of ITO were formed on the TiO ₂ film. Subsequently, a perovskite layer, a P-type semiconductor layer, and a second conductive layer were formed in the same manner as in Example 4, and a solid junction photoelectric conversion element was produced and evaluated.

[Example 8]
In Example 4, a DMF solution for forming a perovskite layer was spin-coated, and a perovskite layer having a thickness of 300 nm was formed by gently spraying hot air of 40 ° C. on the coating surface to dry it. In the same manner as in Example 4, a solid junction photoelectric conversion element was produced. This was evaluated in the same manner as in Example 4.

[Example 9]
In Example 2, a DMF solution for forming a perovskite layer was spin-coated, and a perovskite layer having a thickness of 300 nm was formed by gently blowing hot air at 40 ° C. onto the coating surface to dry it. In the same manner as in Example 2, a solid junction photoelectric conversion element was produced. This was evaluated in the same manner as in Example 2.

[Example 10]
In Example 5, except that a DMF solution for forming a perovskite layer was spin-coated, and a perovskite layer having a thickness of 300 nm was formed by gently blowing hot air at 40 ° C. onto the coating surface to dry it. In the same manner as in Example 5, a solid junction photoelectric conversion element was produced. This was evaluated in the same manner as in Example 5.

[Example 11]
In Example 8, a DMF solution for forming a perovskite layer was spin-coated, an appropriate amount of toluene was dropped onto the coating surface to diffuse toluene over the entire coating surface, and then warm air at 40 ° C. was gently applied. A solid junction photoelectric conversion element was produced in the same manner as in Example 8 except that a perovskite layer having a thickness of 300 nm was formed by spraying and drying. This was evaluated in the same manner as in Example 8.

[Example 12]
In Example 9, a DMF solution for forming a perovskite layer was spin-coated, an appropriate amount of toluene was dropped onto the coating surface to diffuse toluene over the coating surface, and then warm air at 40 ° C. was gently applied. A solid junction photoelectric conversion element was produced in the same manner as in Example 9 except that a perovskite layer having a thickness of 300 nm was formed by spraying and drying. This was evaluated in the same manner as in Example 9.

[Example 13]
In Example 10, a DMF solution for forming a perovskite layer was spin-coated, an appropriate amount of toluene was dropped onto the coating surface to diffuse toluene over the entire coating surface, and then warm air at 40 ° C. was gently applied. A solid junction photoelectric conversion element was produced in the same manner as in Example 10 except that a perovskite layer having a thickness of 300 nm was formed by spraying and drying. This was evaluated in the same manner as in Example 10.

[Example 14]
In Example 12, after diffusing toluene over the entire coating surface, a solid perovskite layer having a thickness of 300 nm was formed by gently blowing hot air at 100 ° C. and drying to form a solid as in Example 12. A junction type photoelectric conversion element was produced. This was evaluated in the same manner as in Example 9.

[Example 15]
In Example 13, after diffusing toluene over the entire coating surface, a solid perovskite layer having a thickness of 300 nm was formed by gently blowing hot air at 100 ° C. and drying to form a solid as in Example 13. A junction type photoelectric conversion element was produced. This was evaluated in the same manner as in Example 13.

[Comparative Example 1]
A PEN substrate having an ITO surface etched as in Example 1 was obtained. The ITO surface was not roughened, and a perovskite layer and a second conductive layer were formed by the same method as in Example 1, and a solid junction photoelectric conversion element was produced and evaluated.
As a result, Rz was less than 1 nm which is the measurement limit of the measurement method.

[Comparative Example 2]
A TiO ₂ film was formed in the same manner as in Example 4, and this surface was not roughened. Subsequently, in the same manner as in Example 4, a perovskite layer, a P-type semiconductor layer, and a second conductive layer were formed. A solid junction photoelectric conversion element was prepared and evaluated.

Table 1 shows the configuration and evaluation results of the solid junction photoelectric conversion element fabricated as described above. The symbols in Table 1 have the following meanings: S: base material, C1: first conductive layer, N: N-type semiconductor layer, A (ITO): ITO anchor layer, A (TiO ₂ ): TiO ₂ anchor layer, A (Al ₂ O ₃ ): Al ₂ O ₃ anchor layer, E: perovskite layer, P: P-type semiconductor layer, C2: second conductive layer.

FIG. 10 is a graph plotting the relationship between the average value of Rz-a and the leak occurrence frequency in each example and each comparative example.
FIG. 11 is a graph in which the relationship between the roughness ratio represented by (average value of Rz-a) / (average value of Rz-b) and the average value of photoelectric conversion efficiency in each example and each comparative example is plotted. Indicates.

From Examples 8 to 13, it is clear that by gently blowing warm air during the formation of the perovskite layer, the Rz-b value is drastically lowered and the production yield and photoelectric conversion efficiency are markedly improved.
From Examples 11 to 13, when the perovskite layer was formed, a poor solvent layer was laminated on the perovskite layer, and then the warm air was gently blown, whereby the Rz-b value was further reduced and the production yield was increased. It is understood that the photoelectric conversion efficiency is further improved.
From Examples 14 to 15, it is understood that the temperature of the warm air blown during the formation of the perovskite layer is preferably less than 100 ° C, more preferably about 40 to 70 ° C.
From the above results, it is clear that the solid junction photoelectric conversion element according to the present invention is less prone to leakage current and is manufactured with a high yield.

  The configurations and combinations thereof in the embodiments described above are examples, and the addition, omission, replacement, and other modifications of the configurations can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... 1st conductive layer, 2 ... 2nd conductive layer, 3 ... Perovskite layer, 4 ... Base material, 5 ... Anchor layer, 6 ... N type semiconductor layer, 7 ... P type semiconductor layer, K ... Bonding surface, J1, J2 ... Joint surface, 10A-10G ... Solid-junction photoelectric conversion element

Claims (13)

A solid junction photoelectric conversion element comprising a first conductive layer, a perovskite layer, and a second conductive layer in this order,
Of two adjacent layers adjacent to both sides of the perovskite layer, the maximum height roughness (Rz) of the bonding surface in contact with the perovskite layer in at least one adjacent layer is 1 nm or more,
The Rz is a solid junction photoelectric conversion element that is a sum of a peak height maximum value (Rp) and a valley depth maximum value (Rv) within a reference length (L) on the bonding surface.   In a cross-sectional view including the joint surface in the thickness direction, out of the square area S (= L × Rz) in which the reference length (L) is the horizontal side and the Rz is the vertical side, The solid junction photoelectric conversion element according to claim 1, wherein the occupation ratio is 10 to 90%.   3. The solid junction photoelectric conversion element according to claim 1, wherein the first conductive layer is an adjacent layer having an Rz of 1 nm or more. An anchor layer containing fine particles is provided between the first conductive layer and the perovskite layer,
The solid junction photoelectric conversion element according to claim 1, wherein the anchor layer is an adjacent layer having an Rz of 1 nm or more. An N-type semiconductor layer is provided between the first conductive layer and the perovskite layer,
The solid junction photoelectric conversion element according to claim 1, wherein the N-type semiconductor layer is an adjacent layer having the Rz of 1 nm or more. Between the first conductive layer and the perovskite layer, an N-type semiconductor layer and an anchor layer containing fine particles are provided in this order,
The solid junction photoelectric conversion element according to claim 1, wherein the anchor layer is an adjacent layer having an Rz of 1 nm or more. An N-type semiconductor layer is provided between the first conductive layer and the perovskite layer,
The N-type semiconductor layer is an adjacent layer having the Rz of 1 nm or more,
The first conductive layer is adjacent to the N-type semiconductor layer, and the maximum height roughness (Rz ′) of the bonding surface in contact with the N-type semiconductor layer in the first conductive layer is 1 nm or more,
The Rz ′ is a sum of a peak height maximum value (Rp) and a valley depth maximum value (Rv) within a reference length (L) in the joint surface of the first conductive layer. The solid junction photoelectric conversion element described. A P-type semiconductor layer is provided between the perovskite layer and the second conductive layer,
The solid junction photoelectric conversion element according to any one of claims 1 to 7, wherein the P-type semiconductor layer is an adjacent layer having an Rz of 1 nm or more. A substrate in contact with the surface of the first conductive layer opposite to the perovskite layer;
The maximum height roughness (Rz ″) of the bonding surface in contact with the first conductive layer in the substrate is 1 nm or more,
The Rz ″ is the sum of a peak height maximum value (Rp) and a valley depth maximum value (Rv) within a reference length (L) on the joint surface of the base material. The solid junction photoelectric conversion element according to one item. The Rz (Rz-a) in the adjacent layer on the first conductive layer side and the Rz (Rz-b) in the adjacent layer on the second conductive layer side are 1 nm or more,
The solid junction photoelectric conversion element according to any one of claims 1 to 9, wherein a roughness ratio represented by (Rz-a) / (Rz-b) is 0.1 or more and 1000 or less. A manufacturing method of a solid junction photoelectric conversion element comprising a perovskite layer and an adjacent layer having a bonding surface in contact with the perovskite layer,
A step of applying a solution containing a compound that forms the perovskite layer to the bonding surface of the adjacent layer to form a coating film; and a step of forming the perovskite layer by drying the coating film. And
The maximum height roughness (Rz) of the joint surface is 1 nm or more,
The Rz is a method for manufacturing a solid junction photoelectric conversion element, which is a sum of a peak height maximum value (Rp) and a valley depth maximum value (Rv) within a reference length (L) on the bonding surface.   The manufacturing method of the solid junction type photoelectric conversion element of Claim 11 which dries the said coating film by spraying a 40-60 degreeC hot air on the said coating film, and forms the said perovskite layer.   The method for producing a solid junction photoelectric conversion element according to claim 11, wherein a poor solvent for the compound is dropped onto the coating film, and then the coating film is dried to form the perovskite layer.

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