JP2022117248A - Perovskite solar cell and method for manufacturing the same - Google Patents

Abstract

To provide an easy-to-manufacture perovskite solar cell and a perovskite solar cell that is less susceptible to the layers below.SOLUTION: A method for manufacturing a solar cell having a first flexible substrate 3, a first electrode 5, a photoelectric conversion layer 7, 9, 11 having a perovskite layer, a second electrode 13, and a second flexible substrate 15 in this order, includes the steps of preparing a first film including the first flexible substrate 3 and the first electrode 5 and a second film including the second electrode 13 and the second flexible substrate 15, and pasting the first and second films together.SELECTED DRAWING: Figure 1

Description

The present invention relates to a perovskite solar cell and its manufacturing method.

Japanese Patent Application Laid-Open No. 2019-55916 describes a perovskite solar cell and a manufacturing method thereof. A perovskite solar cell has a laminated structure including a front substrate, a front electrode, a perovskite layer, a back electrode and a back electrode. And the manufacturing method is to form each layer in turn. When the layers are sequentially formed to obtain a laminated structure, there are problems that the upper layers are easily affected by the lower layers, and that the patterning and etching operations for each layer are time-consuming.

JP 2019-55916 A

One of the objects of the present invention is to provide a perovskite solar cell that is easy to manufacture and to provide a perovskite solar cell that is less susceptible to the effects of underlying layers.

The above problems are basically solved by preparing two films and combining them to make a solar cell.

According to the present invention, a perovskite solar cell having not only initial characteristics but also high durability can be provided.

FIG. 1 is a conceptual diagram showing the basic configuration of a solar cell. FIG. 2 is a flow chart for explaining an example of a method for manufacturing a solar cell. FIG. 3 is a conceptual diagram showing the first film and the second film. FIG. 4 is a conceptual diagram showing that the first film has a first connection electrode and the second film has a second connection electrode. FIG. 5 is a conceptual diagram showing that the second film has a second connection electrode. FIG. 6 is a flow chart showing that the order of forming the hole-transporting layer and the electron-transporting layer is opposite to that of FIG. FIG. 7 is a flow chart showing an example of making a solar cell using a first film having a hole-transporting layer and a second film having an electron-transporting layer and a perovskite layer. FIG. 8 is a conceptual diagram showing the first film and the second film obtained according to the flow chart of FIG. FIG. 9 is a conceptual diagram showing a first film and a second film each having a perovskite precursor layer. FIG. 10 is a conceptual diagram showing that the first film and the second film each have a perovskite layer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments for carrying out the present invention will be described below with reference to the drawings. The present invention is not limited to the embodiments described below, and includes appropriate modifications within the scope obvious to those skilled in the art from the following embodiments.

About Solar Cells The first invention relates to solar cells. FIG. 1 is a conceptual diagram showing the basic configuration of a solar cell. As shown in FIG. 1, this solar cell 1 includes a first flexible substrate 3, a first electrode 5, photoelectric conversion layers 7, 9 and 11 having perovskite layers, and a second electrode 13. , and a second flexible substrate 15 in this order. The photoelectric conversion layers 7 , 9 , 11 may have a hole transport layer 7 , a perovskite layer 9 and an electron transport layer 11 .

flexible substrates 3, 15
As the flexible substrates 3 and 15, known substrates for organic solar cells, organic EL elements, and the like can be appropriately used. Specific examples of the substrate include glass, ceramics, and resin films. Specific examples of resin films include ionomer film, polyethylene film, polyethylene terephthalate film, polyethylene naphthalate film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, polypropylene film, polyester film, polycarbonate film, polystyrene film, poly Examples include acrylonitrile film, ethylene-vinyl acetate copolymer film, ethylene-vinyl alcohol copolymer film, ethylene-methacrylic acid copolymer film, nylon film, etc., which may be formed singly or as a mixture of two or more. do not have. Moreover, these films may be laminated and formed. A substrate having at least one film selected from a metal film, a semiconductor film, a conductive film and an insulating film formed on part or all of these surfaces can also be used.

Examples of metals are one or more metals selected from gallium, iron, indium, aluminum, vanadium, titanium, chromium, rhodium, nickel, cobalt, zinc, magnesium, calcium, silicon, yttrium, strontium and barium. be. Examples of semiconductor film constituent materials include simple elements such as silicon and germanium, compounds containing elements of Groups 3 to 5 and Groups 13 to 15 of the periodic table, metal oxides, metal sulfides, and metals. Selenides, metal nitrides, and the like can be mentioned, and they are contained singly or in combination of two or more. Further, examples of constituent materials of the conductive film are tin-doped indium oxide (ITO), fluorine-doped indium oxide (FTO), zinc oxide (ZnO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), Tin oxide (SnO ₂ ), titanium oxide (TiO ₂ ), indium oxide (In ₂ O ₃ ), and tungsten oxide (WO ₃ ) can be mentioned, and they are contained singly or in combination of two or more. Examples of constituent materials of the insulating film include aluminum oxide _{( Al2O3} ), silicon oxide _{( SiO2} ), silicon nitride _{( Si3N4} ) _, and silicon oxynitride ( _Si4O5N3 ). .

Examples of the shape of the substrate include a plate shape such as a flat plate or disk, a fibrous shape, a rod shape, a cylindrical shape, a prismatic shape, a cylindrical shape, a spiral shape, a spherical shape, a ring shape, and a porous structure. Among these, a plate-shaped substrate is preferable. Examples of the thickness of the substrate are preferably 0.1 μm to 100 mm, more preferably 1 μm to 10 mm.

First electrode 5, second electrode 13
The electrode is a layer that serves as a support for the electron transport layer and has a function of extracting electrons from the perovskite layer (light absorption layer). The electrodes are formed on the substrate 3 and include spaced apart first and second electrodes 5a and 5b. Being separated means that they are not in physical contact and that the first electrode 5a and the second electrode 5b are not short-circuited. The electrodes are preferably transparent electrodes or metal electrodes.

Examples of transparent electrodes include carbon, metals, and conductive metal oxides. Examples of carbon include carbon black, carbon nanotube, and graphene, and examples of metal include gold, silver, copper, aluminum, nickel, indium, and titanium. As the oxide semiconductor, a tin-doped indium oxide (ITO) film, an impurity-doped indium oxide (In ₂ O ₃ ) film, an impurity-doped zinc oxide (ZnO) film, a fluorine-doped tin dioxide (FTO) film, and a stack of these films are used. It is a laminated film consisting of A metal electrode means an electrode comprising metal. And examples of metal electrodes are gold, silver, and copper. Metal electrodes include not only metal but also tin-doped indium oxide (ITO) film, impurity-doped indium oxide (In ₂ O ₃ ) film, impurity-doped zinc oxide (ZnO) film, fluorine-doped tin dioxide (FTO) film on the surface of metal. ) film, or a laminated film formed by laminating these. These films may, for example, function as diffusion barrier layers. The thickness of these electrodes is not particularly limited, and it is usually preferable to adjust the sheet resistance to 5 to 15 Ω/□ (per unit area). The electrodes can be obtained by a known film forming method depending on the material to be formed.

Also, the first electrode may have a structure that allows light to pass through, such as a mesh shape or a stripe shape. Furthermore, a metal lead wire may be used together for the purpose of lowering electrical resistance. Metal leads include aluminum, silver, gold, titanium, and the like.

electron transport layer 11
The electron transport layer 11 is formed to increase the active surface area of the perovskite layer (light absorption layer), improve the photoelectric conversion efficiency, and facilitate electron collection. The electron transport layer may be a flat layer using an organic semiconductor material such as a fullerene derivative. Alternatively, the electron transport layer may be a layer containing metal oxides such as titanium oxide (TiO ₂ ) (including mesoporous TiO ₂ ), tin oxide (SnO ₂ ), and zinc oxide (ZnO). The thickness of the electron transport layer is not particularly limited, and is preferably about 10 to 300 nm, more preferably about 10 to 250 nm, from the viewpoint of collecting more electrons from the perovskite layer (light absorption layer). The electron transport layer 11 may contain or consist of an n-type metal oxide semiconductor. In particular, when the first film and the second film are laminated to manufacture a solar cell as in the present invention, the electron transport layer 11 preferably contains an n-type metal oxide semiconductor.

hole transport layer 7
The hole transport layer 7 is a layer having a function of transporting charges. A hole transport layer 7 is a layer formed on the perovskite layer 9 . For example, a conductor, a semiconductor, an organic hole transport material, or the like can be used for the hole transport layer. The material can function as a hole transport material that accepts holes from the perovskite layer (light absorbing layer) and transports the holes. A hole-transporting layer is formed on the perovskite layer (light-absorbing layer). Examples of the conductors and semiconductors include compound semiconductors containing monovalent copper such as _{CuI , CuSCN , CuInSe 2} and CuS; Examples include compounds containing metals other than copper. Among them, semiconductors containing monovalent copper are preferable, and CuI and CuSCN are more preferable, from the viewpoint of receiving only holes more efficiently and obtaining higher hole mobility. Examples of organic hole transport materials include polythiophene derivatives such as poly-3-hexylthiophene (P3HT) and polyethylenedioxythiophene (PEDOT); fluorene derivatives such as -p-methoxyphenylamine)-9,9′-spirobifluorene (Spiro-OMeTAD); carbazole derivatives such as polyvinylcarbazole; poly[bis(4-phenyl)(2,4,6-trimethylphenyl ) amine] (PTAA) and other triphenylamine derivatives; diphenylamine derivatives; polysilane derivatives; and polyaniline derivatives. Among them, triphenylamine derivatives, fluorene derivatives and the like are preferable, and PTAA, Spiro-OMeTAD and the like are more preferable, from the viewpoint of receiving only holes more efficiently and obtaining higher hole mobility. However, when manufacturing a solar cell by laminating the first film and the second film as in the present invention, the hole transport layer preferably contains a polythiophene derivative.

Lithium bis(trifluoromethylsulfonyl)imide (LiTFSI), silver bis(trifluoromethylsulfonyl)imide, trifluoromethylsulfonyloxysilver , NOSbF ₆ , SbCl ₅ , SbF ₅ , tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III) tri[bis(trifluoromethane)sulfonimide],4-isopropyl- Oxidizing agents such as 4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate can also be included. The hole transport layer may also contain basic compounds such as t-butylpyridine (TBP), 2-picoline, 2,6-lutidine and the like. The contents of the oxidizing agent and the basic compound can be conventionally used amounts. The film thickness of the hole transport layer is preferably 10 to 1000 nm, more preferably 100 to 500 nm, from the viewpoint of receiving only holes more efficiently and obtaining higher hole mobility.

Perovskite layer 9
The perovskite layer (light absorption layer: photoactive layer) 9 in the perovskite solar cell is a layer that performs photoelectric conversion by absorbing light and moving excited electrons and holes.
A compound represented by the general formula (ABX ₃ ) is used for the perovskite layer. This compound may be a perovskite crystal or a perovskite complex.
A is methylamine, ethylamine, n-butylamine, di-n-butylamine, di-n-hexylamine, trimethylamine, triethylamine, methyl-n-hexylamine, methyldiethylamine, tri-n-hexylamine, tri-t-butylamine , imidazole, pyrrole, aziridine, carbazole, formamidine, guanidine, aniline, pyridine, 4-t-butylpyridine, phenethylamine, organic amino compounds such as 5-aminovaleric acid, cesium, potassium, rubidium, etc. and may be used singly or as a mixture of two or more.
B can include divalent cations such as lead and tin, and may be used alone or in combination. Also, a small amount of trivalent cations such as indium and antimony may be mixed.
X can include halogen atoms such as chlorine, bromine and iodine, and anion sources, and may be used alone or in combination of two or more.

The perovskite layer (light absorption layer) includes perovskite materials and perovskite complexes. The film thickness of the perovskite layer (light absorption layer) is preferably, for example, 50 to 1000 nm, preferably 200 to 800 nm, from the viewpoint of the balance between the light absorption efficiency and the diffusion length of electrons and holes, and the absorption efficiency of light reflected by the electrode. more preferred. The film thickness of the perovskite layer (light absorbing layer) of the present invention may be measured with a cross-sectional scanning electron microscope (cross-sectional SEM).
In addition, the flatness of the perovskite layer (light absorption layer) of the present invention is preferably such that the height difference is 50 nm or less (-25 nm to +25 nm) in the horizontal direction of the surface in the range of 500 nm × 500 nm measured with a scanning electron microscope. , the height difference is preferably 40 nm or less (-20 nm to +20 nm). This makes it easier to balance the light absorption efficiency and the exciton diffusion length, and further improves the absorption efficiency of the light reflected by the electrode.

The photoelectric conversion layers 7, 9, 11 may have the hole transport layer 7, the perovskite layer 9, and the electron transport layer 11 in this order. In this case, the electron transport layer 11 or the second electrode 13 preferably contains a conductive polymer containing poly-3,4-ethylenedioxythiophene:poly-4-styrenesulfonate.

Moreover, the photoelectric conversion layers 7, 9, and 11 may have the electron transport layer 11, the perovskite layer 9, and the hole transport layer 7 in this order. In this case, the electron transport layer 11 preferably contains SnO ₂ or TiO ₂ .

FIG. 2 is a flow chart for explaining an example of a method for manufacturing a solar cell. As shown in FIG. 2, the method includes providing a first film 21 comprising a first flexible substrate 3 and first electrodes 5 . In parallel therewith, a step of preparing a second film 23 including a second electrode 13 and a second flexible substrate 15 is included. The process of forming electrodes on flexible substrates is well known. Either or both of the first film 21 and the second film 23 may further have photoelectric conversion layers 7, 9, 11 and connection electrodes 25, 27. FIG. Methods for providing these are also known. Electrodes may be formed on the flexible substrate by sputtering. Electrodes may also be formed on the flexible substrate using a conductive paste.

Connection electrodes 25, 27
The connection electrode is an electrode for obtaining conduction between the first electrode 5 and the second electrode 13 .

An example of the process of preparing the first film 21 including the first flexible substrate 3 and the first electrode 5 is shown in steps 201-202 of FIG. A substrate with a back pattern electrode is prepared (S201). Incidentally, the electrode at this time may be used as a connection electrode. Next, connection electrodes are formed in contact with the back pattern electrodes (S202). The second film 21 thus obtained is as shown in FIG. FIG. 3 is a conceptual diagram showing the first film and the second film. A method of forming an electrode on a flexible substrate and forming a photoelectric conversion layer on the electrode is known.

Step of preparing a substrate with a back pattern electrode (S201)
An electrode is formed on the substrate. The electrodes may include spaced apart first and second electrodes. Methods for forming electrodes on substrates are known. Examples of known methods are etching with a resist pattern and patterning using a laser.

Step of forming a connection electrode in contact with the back pattern electrode (S202)
Screen printing, for example, may be used to form the connection electrodes. Alternatively, a metal may be vapor-deposited using a mask to form a connection electrode.

An example of the process of preparing the second film 23 including the second electrode 13 and the second flexible substrate 15 is shown in steps 101-105 of FIG. A substrate with surface pattern electrodes is prepared (S101). Next, an electron transport layer is formed (S102). Next, a perovskite layer is formed (S103). Next, a hole transport layer is formed (S104). After that, the photoactive layer (photoelectric conversion layer) is patterned. The second film 23 thus obtained is as shown in FIG.

Step of preparing a substrate with surface pattern electrodes (S101)
An electrode is formed on the substrate. The electrodes may include spaced apart first and second electrodes. Methods for forming electrodes on substrates are known. Examples of known methods are etching with a resist pattern and patterning using a laser.

Step of forming an electron transport layer (S102)
The electron transport layer can be obtained using a known film formation method depending on the material to be formed. For example, it can be produced by applying an aqueous dispersion of 3 to 15 mass % (especially 5 to 10 mass %) tin oxide fine particles onto the electrode. A known or commercially available tin oxide fine particle aqueous dispersion can be used. A preferred coating method is spin coating. Incidentally, the coating can be performed at, for example, about 15 to 30.degree. After forming the electrode and the electron transport layer on the substrate, etching using a resist pattern or patterning using a laser may be performed.

Step of forming a perovskite layer (S103)
An example of a process for forming a perovskite layer includes, in this order, a process of applying a solution containing a perovskite compound to a substrate, a process of applying a poor solvent to the substrate, and a process of annealing the substrate. Spin coating, dip coating, screen printing, roll coating, die coating, transfer printing, spraying, or slit coating may be used to apply the solution containing the perovskite compound to the substrate. Among these, it is preferable to apply the solution onto the substrate by spin coating. Spin coating is a method of applying the solution onto the substrate by dropping the solution and rotating the substrate. Alternatively, the substrate on which the solution is mounted may be rotated and the solution may be further applied to the substrate. As for the rotation speed, the maximum speed is 1000 to 10,000 rpm for 30 seconds to 5 minutes, the maximum speed is 2 seconds to 15 seconds, and the maximum speed to stop is 2 seconds to 15 seconds.

Next, the step of coating the substrate with the poor solvent will be described.
A poor solvent means a solvent that has the ability to dissolve a solute but does not have a high solubility for the solute. Examples of poor solvents include substituted aliphatic hydrocarbons such as dichloromethane and chloroform; aromatic hydrocarbons such as toluene and benzene; substituted aromatic hydrocarbons such as chlorobenzene, orthodichlorobenzene and nitrobenzene; ); alcohols such as methanol, ethanol, isopropanol, butanol, octanol; long-chain hydrocarbons (particularly C4-10 hydrocarbons) such as hexane; These poor solvents can be used alone or in combination of two or more. Among these, chlorobenzene or toluene is preferred.

Next, the process of annealing the substrate will be described. Annealing means a process of heating the substrate. The annealing step is preferably performed immediately after the poor solvent is dropped or after the substrate stops after the spin coating is completed. The annealing process preferably includes a process of stepwise heating the substrate in a closed system containing solvent vapor, as shown in the examples described later. In a closed system, the vapor of the solvent contained in the solution containing the Sn-based perovskite compound preferably exists, and in the closed system, the solvent has a saturated vapor pressure or a partial pressure of 90% or more of the saturated vapor pressure. preferably.

Step of forming a hole transport layer (S104)
A known method may be appropriately adopted as a method for forming the hole transport layer. For example, a solution containing an organic hole transport material is applied (spin coat, ink jet, die coater, etc.) on the perovskite layer (light absorption layer) in a dry atmosphere, and heated at 30 to 150°C (especially 50 to 100°C). It is preferable to form the hole transport layer 11 by The device material 21 can be obtained by forming the hole transport layer.

After that, the first film 21 and the second film 23 are pasted together (S301). Then, the solar cell shown in FIG. 1 can be obtained. By stacking the first film 21 and the second film 23 and applying pressure, the two films may be pasted together. At this time, it may be heated.

The first film 21 may further include photoelectric conversion layers 7 , 9 , 11 . That is, the first film 25 may include the photoelectric conversion layers 7 , 9 and 11 in addition to the second electrode 13 and the second flexible substrate 15 .

FIG. 4 is a conceptual diagram showing that the first film has a first connection electrode and the second film has a second connection electrode. A solar cell is obtained by laminating the two films shown in FIG. The first electrode 5 and the second electrode 13 of this solar cell are electrically connected through a first connection electrode portion 25 and a second connection electrode portion 27 . Thus, the two films may each have a connection electrode.

FIG. 5 is a conceptual diagram showing that the second film has a second connection electrode. A solar cell is obtained by laminating the two films shown in FIG. The first electrode 5 and the second electrode 13 of this solar cell are electrically connected through the second connection electrode portion 27 . In this way, two films of the second film 23 may each have a connection electrode.

FIG. 6 is a flow chart showing that the order of forming the hole-transporting layer and the electron-transporting layer is opposite to that of FIG. Thus, the hole-transporting layer and the electron-transporting layer may be reversed from those in FIG.

In the above method, the first film 21 may have a portion of the photoelectric conversion layer and the second film 23 may have the remainder of the photoelectric conversion layer. Then, after the first film 21 and the second film 23 are bonded together, the photoelectric conversion layer is completed.

FIG. 7 is a flow chart showing an example of making a solar cell using a first film having a hole-transporting layer and a second film having an electron-transporting layer and a perovskite layer. A schematic of the first and second films obtained according to the flow chart of FIG. 7 is shown in FIG. FIG. 8 is a conceptual diagram showing the first film and the second film obtained according to the flow chart of FIG. As shown in FIG. 8, in this example the first film 21 has the hole transport layer 7 and the second film 23 has the electron transport layer 11 and the perovskite layer 9 . In this example, the photoelectric conversion layer 7.9.11 is completed after the first film and the second film are bonded together.

In the above method, the first film 21 may further have a first perovskite precursor layer 31 and the second film 23 may further have a second perovskite precursor layer 33 . FIG. 9 is a conceptual diagram showing a first film and a second film each having a perovskite precursor layer. In this case, the first perovskite precursor layer 31 and the second perovskite precursor layer 33 will form the perovskite layer 9 after the first film 21 and the second film 23 are laminated. .

Perovskite Precursor Layer A perovskite precursor layer means a layer that becomes a perovskite layer by performing a predetermined treatment. For example, the first perovskite precursor layer 31 and the second perovskite precursor layer 33 contain elements that, when combined in their respective compositions, constitute the perovskite layer, and the first film 21 and the second film 23 are It is sufficient that it has a composition that forms the perovskite layer 9 when bonded together. Perovskite precursors are known, for example, as described in JP-A-2019-055916. The perovskite precursor layer may contain a known perovskite precursor as appropriate. For example, the complex is a compound represented by the formula (AM _n1 X _m1 ) and (1) 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)pyrimidinone (abbreviated as “DMTHP”), (2) sulfolane (tetrahydrothiophene 1,1-oxide: abbreviated as “SU”), (3) tetramethylene sulfoxide (abbreviated as “TS”), or (4) N,N-dimethylacetamide (abbreviated as “DMA” ) is the perovskite precursor.
A is a methylammonium cation ( _CH3NH3 ⁺ ), a formamidinium cation _{( NH2CHNH2 +} ), or a cesium cation (Cs ^{+ )} ;
M is Pb ²⁺ , Ge ²⁺ , or Sn ²⁺ ;
X is F ⁻ , Cl ⁻ , Br ⁻ , or I ⁻ ;
n1 is 0.8 to 1.2,
m1 is 2.8 to 3.2.
When the film containing the above complex is heated, the molecule (L) separates and forms a perovskite compound. For example, the perovskite layer 9 can be obtained by heating after bonding the first film 21 and the second film 23 together.

In the above method, the first film 21 further comprises a first perovskite layer 37, the second film 23 further comprises a second perovskite layer 39, the first perovskite layer 37 and the second perovskite Layers 39 may together constitute a perovskite layer. FIG. 10 is a conceptual diagram showing that the first film and the second film each have a perovskite layer. For example, a first perovskite layer is formed on the surface of the first film 21 . A second perovskite layer having the same composition as the first perovskite layer is formed on the surface of the second film 23 . When these two films are pressed together, perovskite layers having, for example, the same composition are welded together to form one perovskite layer. By doing so, the two films can be easily pressure-bonded.

In the above method, the first electrode 5 and the second electrode 13 are separated in the region between the first electrode 5 and the second electrode 13 where the photoelectric conversion layers 7, 9, and 11 do not exist. It may be connected so as to be conductive via the first connection electrode portion 25 provided on the first electrode 5 . The first connection electrode portion 25 may have a projecting shape. If the first connection electrode portion 25 has a protruding shape, even if a thin layer is formed on the second electrode 13, it penetrates through the thin layer to ensure conduction with the second electrode 13. It is preferable because it can be done.

In this example, for example, a second electrode (surface electrode) 13 is provided on a second flexible substrate 15 , and photoelectric conversion layers 7 , 9 and 11 are provided on the surface electrode 13 . On the other hand, in this example, the photoelectric conversion layers 7, 9, and 11 are not provided on the entire surface of the surface electrode 13, but on the surface of the surface electrode 13, and the photoelectric conversion layers 7, 9, and 11 do not exist. There is an area (this area will be referred to as area A). On the other hand, a first electrode (back electrode) 5 is provided on the first flexible substrate 3 . The first flexible substrate 3 and the second flexible substrate 15 have corresponding shapes and are bonded together to form a solar cell. A connection electrode portion 25 is present in a region corresponding to the region A on the back electrode 5 . Then, after the first flexible substrate 3 and the second flexible substrate 15 are bonded together, the first connection electrode portion 25 comes into contact with the surface electrode 13 . As a result, the first electrode 5 and the second electrode 13 are electrically connected via the first connection electrode portion 25 .

The solar cell manufactured as described above has the following configuration. That is, this solar cell includes a first flexible substrate 3, a first electrode 5 which is a transparent electrode, photoelectric conversion layers 7, 9 and 11 having a perovskite layer 9, a second electrode 13, The second flexible substrate 15 is arranged in this order. Then, the first electrode 5 and the second electrode 13 are arranged in a region between the first electrode 5 and the second electrode 13 where the photoelectric conversion layers 7, 9, and 11 do not exist. They are connected so as to be conductive via a first connection electrode portion 25 provided on the electrode 5 .

As shown in FIG. 1, this solar cell has, for example, a region where the photoelectric conversion layers 7, 9 and 11 do not exist between the first flexible substrate 3 and the second flexible substrate 15. exists. In particular, this solar cell preferably has a region where the hole transport layer 7 and the perovskite layer 9 are not present between the first flexible substrate 3 and the second flexible substrate 15 .

In this solar cell, the hole transport layer 7 preferably covers the perovskite layer 9 as shown in FIG. Also, the hole transport layer 7 may exist wider than the perovskite layer 9 . When the first film 21 and the second film are bonded together, the hole transport layer 7 serves as an adhesive surface with the first electrode. By covering the perovskite layer 9 with the hole transport layer 7 that serves as the adhesion surface, the hole transport layer 7 protects the perovskite layer 9 from oxygen and moisture, thereby improving the durability.

In the above method, the first electrode 5 and the second electrode 13 are defined as a region (region In A), it may be connected so as to be conductive via the second connection electrode portion 27 provided on the second electrode 13 . In this case, the second connection electrode portion 27 is provided in the region A, and after the first flexible substrate 3 and the second flexible substrate 15 are bonded together, the second connection electrode portion 27 may be in contact with the first electrode (back electrode) 5 . On the other hand, the first connection electrode portion 25 may exist in a region corresponding to the region A on the back electrode 5 . In this case, even if the second connection electrode portion 27 contacts the first connection electrode portion 25 after the first flexible substrate 3 and the second flexible substrate 15 are bonded together, good. In any case, in this manner, the first electrode 5 and the second electrode 13 are connected to the second connection electrode portion 27 (or the second connection electrode portion 27 and the first connection electrode portion 25). ) becomes conductive.

A solar cell manufactured in this manner has the following configuration. This solar cell includes a first flexible substrate 3, a first electrode 5 which is a transparent electrode, photoelectric conversion layers 7, 9 and 11 having a perovskite layer 9, a second electrode 13, a second , and the flexible substrate 15 in this order. Then, the first electrode 5 and the second electrode 13 are arranged in the region between the first electrode 5 and the second electrode 13 where the photoelectric conversion layers 7, 9, and 11 do not exist. The electrodes 13 are electrically connected through a second connection electrode portion 27 provided on the electrode 13 .

A solar cell was produced using the following equipment and tools.
PTFE filter: Agilent Technologies, 5190-5266, 0.45 µm
ITO/PEN film: Oike & Co., Itd., CX13G-125N-U0, 16 Ω/□
Laminator: Nishinbo Mechatronics Inc., PVL0202S
reagent
SnO2 aqueous dispersion: _Alfer Acer, 044592
PEDOT:PSS dispersion: Heraeus, Clevios P VP. Al 4083.
_PbI2 : Tokyo Chemical Industry Co., Ltd., L0279
FAI: Tokyo Chemical Industry Co., Ltd., F1263
MABr: Tokyo Chemical Industry Co., Ltd., M2589
MACl: Tokyo Chemical Industry Co., Ltd., M0138
Ultra-dehydrated DMF: Kanto Chemical Co., Inc., 11339-85
Ultra-dehydrated DMSO: Wako Pure Chemical Industries, Ltd., 049-07213
Ultra-dehydrated acetone: Wako Pure Chemical Industries, Ltd., 013-00356

A PEN film with ITO, which is a transparent electrode, was plasma-treated, and water-soluble SnO ₂ was coated as an electron transport layer, and water-soluble PEDOT:PSS was coated as a hole transport layer. For the SnO ₂ layer, 300 μL of a 15% SnO ₂ aqueous dispersion diluted with pure water (1:1) was dropped onto the substrate, spin-coated (ramp: 2 seconds, 3000 rpm: 20 seconds), and the surface was heated at 150 °C. It was obtained by heat treatment for 30 minutes. For the PEDOT:PSS layer, 300 μL of PEDOT:PSS dispersion was dropped onto the substrate in the same manner and applied by spin coating (ramp 1 second, 500 rpm for 9 seconds, ramp 1 second, 4000 rpm for 30 seconds). It was obtained by heat treatment at 140 °C for 30 min. SnO ₂ and PEDOT:PSS films were deposited in air. All subsequent steps were performed in a glove box (N ₂ gas, H ₂ O < 0.1 ppm, O ₂ < 0.1 ppm).

PbI ₂ (1798 mg, 3.9 mmol) was dissolved in a superdehydrated DMF/DMSO mixture (2.85 mL/0.15 mL) in a glove box. It was stirred at 70 °C for 30 minutes and filtered using a PTFE filter to prepare a 1.3 M PbI ₂ solution. PbI ₂ solution (200 μL) was applied on the substrate coated with SnO ₂ and PEDOT:PSS by spin coating (ramp 2 s, 1500 rpm for 30 s), heat-treated at 70 °C for 1 min, and PbI ₂ got a layer. Part of the SnO ₂ layer, PEDOT:PSS layer and PbI ₂ layer was removed using acetone:DMSO (10:1) solution, and a Cu tape for extraction electrode was attached.

The film substrate and sealant used for immobilization were larger than the substrate coated with SnO ₂ and PEDOT:PSS. A sealant was placed on the film substrate and heat _- treated at 120 °C for 10 minutes.

FAI (60 mg, 0.35 mmol), MABr (6.0 mg, 0.05 mmol) and MACl (6.0 mg, 0.09 mmol) were dissolved in ultradehydrated i-PrOH (10 mL). The mixture was stirred at 40 °C for 30 minutes and filtered using a PTFE filter to prepare an organic cation solution. After 50 μL of organic cation solution was dropped on each substrate, they were quickly stacked. It was transferred to a laminator set at a temperature of 150 °C and pressed under reduced pressure for 10 minutes to form a perovskite layer. After obtaining the above process, a bonded cell was fabricated. When the cross-sectional area of the obtained solar cell was measured, it was found that the PEDOT:PSS layer showed a larger area than the perovskite layer. This is presumed to be due to the expansion of the PEDOT:PSS, which is a soft film, due to the pressure during bonding.

Solar cell characteristics were evaluated at 1 Sun in the atmosphere. The characteristics when light was incident from the SnO ₂ layer side showed an open-circuit voltage of 0.70 V, a short-circuit current density of 17.8 mA/cm ² , a form factor of 0.64, and a conversion efficiency of 8.0%. When light was incident from the PEDOT:PSS layer side, the open-circuit voltage was 0.58 V, the short-circuit current density was 15.4 mA/cm ² , the form factor was 0.61, and the conversion efficiency was 5.45%.

Furthermore, the solar cell characteristics after 100 hours of continuous irradiation were evaluated as the light durability at 1 Sun. As a result, the characteristics when light was incident from the SnO ₂ layer side were an open-circuit voltage of 0.67 V, a short-circuit current density of 16.1 mA/cm2, a form factor of 0.63, and a conversion efficiency of 6.8%. The retention rate was 85% compared with

[Comparative Example 1]
A device was fabricated in the same steps as in Example 1 until the perovskite layer was formed, and a PEDOT:PSS layer was formed thereon. The electrode obtained in this way and the ITO PEN film w were laminated in the same manner as in Example 1 to prepare a cell.
The solar cell characteristics of this cell were performed under atmospheric conditions for 1 Sun. The characteristics when light was incident from the SnO ₂ layer side showed an open-circuit voltage of 0.41 V, a short-circuit current density of 10.3 mA/cm ² , a form factor of 0.33, and a conversion efficiency of 1.4%. When light was incident from the PEDOT:PSS layer side, the open-circuit voltage was 0.33 V, the short-circuit current density was 7.6 mA/cm ² , the form factor was 0.33, and the conversion efficiency was 0.8%. As compared with Example 1, it is clearly inferior in solar cell performance.

Furthermore, the solar cell characteristics after 100 hours of continuous irradiation were evaluated as the light durability at 1 Sun. As a result, the characteristics when light was incident from the SnO ₂ layer side were an open-circuit voltage of 0.16 V, a short-circuit current density of 6.8 mA/cm ² , a form factor of 0.31, and a conversion efficiency of 0.3%. The retention rate compared with the properties was 37.5%. Compared with Example 1, it is clear that the retention rate is low.

As is clear from the above, it is clear that the solar cell of the present invention not only exhibits high initial characteristics, but also has high light durability.

A PET film having a thickness of 50 μm is used for the first and second flexible substrates, and an ITO film having a thickness of about 150 nm is formed in advance on the electrodes thereon to form a pattern. In some cases, the flexible substrate is attached to the glass substrate to facilitate subsequent processes.
First, a water-soluble SnO ₂ solvent is applied onto the first flexible substrate by spin coating and dried by heating at about 150°C. Then, a perovskite solution is spin-coated and dried, and a hole layer is spin-coated and dried. A hole layer was prepared by dissolving LiTFSi in Spiro-MeOTAD in chlorobenzene. If necessary, part of the hole layer and perovskite layer is removed. Laser processing was used as a removal method, but there is also reactive ion etching (RIE) using a metal mask.

On one of the second flexible substrates, silver paste is printed at desired locations by screen printing for electrical connection of the first and second substrates. The concentration thickness was adjusted so that the finished thickness was about 5 to 20 μm. For lamination, align the positions of both films and apply pressure with a roller. Although the pressure depends on the size of the roller, a pressure of about 0.1 kg/cm was applied. In order to soften the surface of the hole layer a little, chlorobenzene was sprayed on the second flexible substrate before lamination. Also, by heating the roller to a constant temperature of about 70°C, the bonding was more effective.

The film is not limited to PET as long as it is flexible. In order to prevent moisture permeation, a flexible film with a barrier layer formed in advance is desirable. In addition to silver paste, connection materials include carbon paste, copper paste, nickel paste, carbon nanotubes, and the like.

A PET film of 50 μm is used for the first and second flexible substrates, and an ITO film of about 150 nm is formed in advance on the electrodes thereon to form a pattern (similar to Example 2). In some cases, the flexible substrate is attached to the glass substrate to facilitate passage.
First, a water-soluble SnO ₂ solvent is applied onto the first flexible substrate by spin coating, and dried by heating at about 150°C. A perovskite solution is spin-coated and dried thereon. If necessary, part of the hole layer and perovskite layer is removed. Methods of removal include laser processing and reactive ion etching (RIE) using a metal mask.

Silver paste is printed at desired locations on the second flexible substrate by screen printing or the like for electrical connection of the first and second substrates. Adjust the finished thickness to be about 5 to 20 μm. After that, a hole layer was applied in a desired pattern shape by an inkjet method. Spin coating is not necessarily suitable because of unevenness due to the material for electrical connection.

It is recommended to align the positions of both films in advance and apply pressure with a roller. A pressure of about 0.1 kg/cm was applied, depending on the roller size. In order to soften the surface of the hole layer, chlorobenzene was sprayed on the first flexible substrate prior to lamination. Further, by heating the roller to a constant temperature of about 70° C., the bonding could be performed more effectively. (Same materials as in Example 2)

In the above embodiments, spin coating was mainly applied, but each layer may be formed by an ink jet method. In that case, the connection electrodes are formed in advance on the first flexible substrate, and the resistance of the connection electrodes can be easily and stably reduced. The connection electrodes to be formed on the first flexible substrate are made by depositing a metal thin film of a single metal such as Pt, Au, Cu, Ag, Ni, Ti, or an alloy thereof on ITO. Films or metal pastes thereof may be used.

A PET film having a thickness of 50 μm, for example, is used for the first and second flexible substrates, and an ITO film having a thickness of about 150 nm is formed in advance on the electrodes thereon to form a pattern. In some cases, the flexible substrate is attached to the glass substrate to facilitate subsequent processes.
After applying SnO ₂ onto the ITO on the first flexible substrate by a spin coating method, a metal mask was set in order to attach Cu/Pt for connection to a part of it, and a film was formed by sputtering. A perovskite layer and a hole layer were sequentially applied thereon in the same manner as in Example 2. When the connecting electrode is formed of a thin film, even the spin coating method does not produce large unevenness in the thickness of the coating. In that case, it is possible to suppress the occurrence of film thickness unevenness by applying the ink jet method. The process and bonding of one second flexible substrate may be the same as in the second embodiment.

INDUSTRIAL APPLICABILITY This invention can be used in fields such as solar cells.

REFERENCE SIGNS LIST 1 solar cell 3 first flexible substrate 5 first electrode 7 electron transport layer 9 perovskite layer 11 hole transport layer 13 second electrode 15 second flexible substrate 21 first film 23 second Film 31 First Perovskite Precursor Layer 33 Second Perovskite Precursor Layer 37 First Perovskite Layer 39 Second Perovskite Layer

Claims (11)

a first flexible substrate (3), a first electrode (5), a photoelectric conversion layer (7, 9, 11) having a perovskite layer, a second electrode (13), and a second flexible substrate A method for manufacturing a solar cell having a flexible substrate (15) in this order,
a first film (21) comprising a first flexible substrate (3) and a first electrode (5);
providing a second film (23) comprising a second electrode (13) and a second flexible substrate (15);
A method for manufacturing a solar cell, comprising a step of laminating a first film (21) and a second film (23). A method of manufacturing a solar cell according to claim 1, wherein the second film (23) further comprises said photoelectric conversion layer (7, 9, 11). A method for manufacturing a solar cell according to claim 1, wherein the first film (21) further comprises a first perovskite precursor layer (31) and the second film (23) is a second perovskite. A method for manufacturing a solar cell, further comprising a precursor layer (33). A method for manufacturing a solar cell according to claim 1, wherein the first film (21) further comprises a first perovskite layer (37) and the second film (23) comprises a second perovskite layer ( 39), wherein the first perovskite layer (37) and the second perovskite layer (39) constitute the perovskite layers. A method for manufacturing a solar cell according to claim 1, wherein the second electrode (13) is formed by sputtering on the second flexible substrate (15) to obtain the second film (23). A method of manufacturing a solar cell, further comprising forming a second electrode (13) on the second flexible substrate (15) using a conductive paste. A method for manufacturing a solar cell according to claim 1,
The first electrode (5) and the second electrode (13) are
In the region between the first electrode (5) and the second electrode (13) where the photoelectric conversion layer (7, 9, 11) does not exist,
A method for manufacturing a solar cell, wherein connection is established through a first connection electrode portion (25) provided on a first electrode (5). A method for manufacturing a solar cell according to claim 1,
The first electrode (5) and the second electrode (13) are
In the region between the first electrode (5) and the second electrode (13) where the photoelectric conversion layer (7, 9, 11) does not exist,
A method for manufacturing a solar cell, wherein the connection is made conductive via a second connection electrode portion (27) provided on a second electrode (13). A first flexible substrate (3), a first electrode (5) which is a transparent electrode, photoelectric conversion layers (7, 9, 11), a second electrode (13), and a second flexible substrate. A solar cell having a flexible substrate (15) in this order,
The photoelectric conversion layer (7, 9, 11) has an electron transport layer (7), a perovskite layer (9), and a hole transport layer (11) in this order,
The solar cell wherein the hole transport layer (11) or the second electrode (13) comprises a conductive polymer comprising poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate). . A first flexible substrate (3), a first electrode (5) which is a transparent electrode, photoelectric conversion layers (7, 9, 11), a second electrode (13), and a second flexible substrate. A solar cell having a flexible substrate (15) in this order,
The photoelectric conversion layer (7, 9, 11) has a hole transport layer (11), a perovskite layer (9), and an electron transport layer (7) in this order,
The solar cell, wherein said electron transport layer (7) _comprises SnO2 or _TiO2 . A first flexible substrate (3), a first electrode (5) which is a transparent electrode, a photoelectric conversion layer (7, 9, 11) having a perovskite layer (9), and a second electrode (13 ) and a second flexible substrate (15) in this order,
The first electrode (5) and the second electrode (13) are
In the region between the first electrode (5) and the second electrode (13) where the photoelectric conversion layer (7, 9, 11) does not exist,
A solar cell which is electrically connected to a first electrode (5) through a first connection electrode portion (25) provided on the first electrode (5). A first flexible substrate (3), a first electrode (5) which is a transparent electrode, a photoelectric conversion layer (7, 9, 11) having a perovskite layer (9), and a second electrode (13 ) and a second flexible substrate (15) in this order,
The first electrode (5) and the second electrode (13) are
In the region between the first electrode (5) and the second electrode (13) where the photoelectric conversion layer (7, 9, 11) does not exist,
A solar cell connected so as to be conductive via a second connection electrode portion (27) provided on a second electrode (13).

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