Multilayer coupling type photoelectric conversion element and method for manufacturing multilayer coupling type photoelectric conversion element

Abstract

The present invention provides a multilayer coupling type photoelectric conversion element capable of preventing contact between water and a perovskite layer and a method for manufacturing the multilayer coupling type photoelectric conversion element. The multilayer coupling type photoelectric conversion element of the embodiment has a stacked body. The stacked body is formed by stacking a first electrode functional layer, a first photoactive layer, an intermediate functional layer, a second photoactive layer, and a second electrode functional layer. The first photoactive layer is composed of crystalline silicon. The second photoactive layer is composed of a photoactive material having a perovskite type crystal structure. A portion of the layer included in the second electrode functional layer is stacked inside the stacked body, and is stacked by extending on the end face in a manner that covers the end of the second photoactive layer located on the end face of the stacked body.

Description

Technical Field

[0001] Embodiments of the present invention relate to a multilayer coupling type photoelectric conversion element and a method for manufacturing the multilayer coupling type photoelectric conversion element. Background Art

[0002] As a multilayer coupling type photoelectric conversion element, a tandem solar cell is known. The tandem solar cell is provided with a second photoelectric conversion element including a second photoactive layer on the light-receiving surface side of a semiconductor substrate, and a first photoelectric conversion element on the opposite side of the light-receiving surface side of the semiconductor substrate, which makes the semiconductor substrate function as a first photoactive layer. As the second photoactive layer, a photoactive layer having a photoactive layer composed of a material with a perovskite type crystal structure (hereinafter referred to as a perovskite layer) is known.

[0003] In a multilayer coupling type photoelectric conversion element having a perovskite layer, the perovskite layer is structurally exposed at its end surface. Therefore, the perovskite layer is in a state where water can easily contact. If the perovskite layer contacts water, the perovskite layer decomposes, and thus the first photoelectric conversion element may be short-circuited.

[0004] [Prior art literature]

[0005] [Patent Document]

[0006] [Patent Document 1] International Publication No. 2016 / 158838 Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a multilayer coupling type photoelectric conversion element and a method for manufacturing the multilayer coupling type photoelectric conversion element which can prevent water from contacting a perovskite layer.

[0008] The multilayer coupling type photoelectric conversion element according to the embodiment includes a stacked body.

[0009] The laminate is formed by laminating a first electrode functional layer, a first photoactive layer, an intermediate functional layer, a second photoactive layer, and a second electrode functional layer.

[0010] The first photoactive layer is composed of crystalline silicon.

[0011] The second photoactive layer is composed of a photoactive material having a perovskite type crystal structure.

[0012] A part of the layers included in the second electrode functional layer is stacked inside the stacked body, and is stacked extending on the end surface so as to cover the end portion of the second photoactive layer located on the end surface of the stacked body. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic cross-sectional view showing a multilayer coupling type photoelectric conversion element according to the first embodiment.

[0014] Figure 2 It is a schematic cross-sectional view showing a multilayer coupling type photoelectric conversion element according to a second embodiment.

[0015] Figure 3 It is a schematic cross-sectional view showing a modification of the multilayer coupling type photoelectric conversion element according to the second embodiment.

[0016] Figure 4 It is a process diagram for explaining the method for manufacturing the multilayer coupling type photoelectric conversion element according to the third embodiment.

[0017] Figure 5 It is a process diagram for explaining the method for manufacturing the multilayer coupling type photoelectric conversion element according to the third embodiment.

[0018] Figure 6 It is a process diagram for explaining the method for manufacturing the multilayer coupling type photoelectric conversion element according to the third embodiment.

[0019] Figure 7 It is a schematic cross-sectional view showing another example of the multilayer coupling type photoelectric conversion element according to the fourth embodiment.

[0020] Figure 8 It is a process diagram for explaining the method for manufacturing the multilayer coupling type photoelectric conversion element according to the fourth embodiment.

[0021] Fig. 9 It is a process diagram for explaining the method for manufacturing the multilayer coupling type photoelectric conversion element according to the fourth embodiment.

[0022] Fig.10 It is a process diagram for explaining the method for manufacturing the multilayer coupling type photoelectric conversion element according to the fourth embodiment. DETAILED DESCRIPTION

[0023] Hereinafter, a multilayer coupling type photoelectric conversion element and a method for manufacturing the multilayer coupling type photoelectric conversion element according to an embodiment will be described with reference to the drawings.

[0024] (First Embodiment)

[0025] Figure 1 A multilayer coupling type photoelectric conversion element 1 according to the first embodiment is shown. Figure 1 The multilayer coupling type photoelectric conversion element 1 shown is composed of a stacked body 7 in which a first electrode functional layer 2, a first photoactive layer 3 composed of crystalline silicon, an intermediate functional layer 4, a second photoactive layer 5 composed of a photoactive material having a perovskite type crystal structure, and a second electrode functional layer 6 are stacked. Figure 1 In the multilayer coupling type photoelectric conversion element 1 shown, the light receiving surfaces of the first photoactive layer 3 and the second photoactive layer 5 are set to be surfaces on the second electrode functional layer 6 side.

[0026] End 2a of first electrode functional layer 2 , end 3a of first photoactive layer 3 , end 4a of intermediate functional layer 4 , end 5a of second photoactive layer 5 , and end 6a of second electrode functional layer 6 are located at end surface 7a of stacked body 7 .

[0027] Figure 1 In the multilayer coupling type photoelectric conversion element 1 shown, a part of the layer 6b included in the second electrode functional layer 6 is stacked inside the stack 7 and is stacked so as to extend and cover a part of the end face 7a of the stack 7. Specifically, a part of the layer 6b included in the second electrode functional layer 6 is stacked so as to extend and cover the end 5a of the second photoactive layer 5. Thus, the end 5a of the second photoactive layer 5 is covered by the part of the layer 6b included in the second electrode functional layer 6.

[0028] The first electrode functional layer 2 may also include a first electrode and a first conductive layer disposed between the first electrode and the first photoactive layer.

[0029] The first photoactive layer 3 is composed of a crystalline silicon layer of the first conductivity type. The crystalline silicon constituting the first photoactive layer 3 can be of the same composition as the silicon generally used in photocells. Specifically, single crystal silicon, polycrystalline silicon, heterojunction silicon and other crystalline silicon containing crystalline silicon can be listed. In addition, the crystalline silicon can also be a thin film cut from a silicon wafer. As the silicon wafer, n-type silicon crystals doped with phosphorus or arsenic, etc., and p-type silicon crystals doped with boron or gallium, etc. can also be used. Since the electrons in the p-type silicon crystal have a long diffusion length, p-type crystalline silicon is preferably used as the crystalline silicon of the first conductivity type.

[0030] The intermediate functional layer 4 has at least the function of connecting in series the bottom unit mainly composed of the first photoactive layer 3 and the top unit mainly composed of the second photoactive layer 5. The intermediate functional layer 4 may also include, for example, a second conductive layer connected to the first photoactive layer 3, a transparent conductive layer, and a first functional layer connected to the second photoactive layer 5.

[0031] The second photoactive layer 5 is composed of a photoactive material having a perovskite crystal structure. The perovskite crystal structure refers to a crystal structure that is the same as that of perovskite. Typically, the perovskite structure is composed of ions A, B, and X. When ion B is smaller than ion A, a perovskite structure is sometimes adopted. The chemical composition of the crystal structure can be represented by the following general formula (1).

[0032] ABX3(1)

[0033] Here, A can utilize primary ammonium ions. Specifically, CH3NH3 + (hereinafter, sometimes referred to as MA), C2H5NH3 + 、C3H7NH3 +、C4H9NH3 + , and HC(NH2)2 + (hereinafter, sometimes referred to as FA), etc., preferably CH3NH3 + , but not limited thereto. In addition, A is also preferably Cs + , and 1,1,1-trifluoro-ethylammonium iodide (FEAI), but the present invention is not limited thereto.

[0034] In addition, B is a divalent metal ion, preferably Pb 2+ or Sn 2+ , but is not limited thereto. In addition, X is preferably a halogen ion. For example, from F - , Cl - Br - ,I - At - Choose from, preferably Cl - Br - ,I - , but is not limited to this.

[0035] The materials constituting the ions A, B or X may be either single or mixed. The ions constituting the ions may not necessarily have the same stoichiometric ratio with ABX3 to still function.

[0036] The ions A constituting the perovskite of the second photoactive layer 5 are preferably composed of an atomic weight or a total of the atomic weights of the constituent ions (molecular weight) of 45 or more. It is further preferred that the ions contain 133 or less. If the ions A under these conditions are monomers, the stability is low, so sometimes a general MA (molecular weight 32) is mixed, but as a series connection that approaches the band gap of silicon 1.1eV when mixed with MA and performs wavelength division to improve efficiency, the overall characteristics are reduced, so it is not preferred. In addition, when ion A is a combination of multiple ions and contains Cs, the ratio of the number of Cs to the total number of ions A is more preferably 0.1 to 0.9.

[0037] This crystal structure has a unit lattice of cubic, tetragonal, orthorhombic, etc., with A arranged at each vertex, B arranged at the body center, and X arranged at each axis of the cubic crystal as the center. In this crystal structure, the octahedron consisting of one B and six Xs contained in the unit lattice is easily deformed and transformed into a symmetrical crystal due to the interaction with A. It is estimated that this phase transition causes the physical properties of the crystal to change drastically, so that electrons or holes are released outside the crystal to cause power generation.

[0038] The second electrode functional layer 6 may include a second electrode 6c and a second functional layer 6d disposed between the second electrode 6c and the second photoactive layer 5. The second functional layer 6d, which is a partial layer 6b included in the second electrode functional layer 6, extends and is stacked on the end surface of the stack 7 so as to cover the end 5a of the second photoactive layer 5.

[0039] The first functional layer (not shown) included in the intermediate functional layer 4 and the second functional layer 6d included in the second electrode functional layer 6 either function as a hole transport layer and the other functions as an electron transport layer with respect to the second photoactive layer 5. In order to achieve a better conversion efficiency, the multilayer coupling type photoelectric conversion element 1 of this embodiment preferably includes both of the above layers, but may include only at least the second functional layer 6d.

[0040] The first conductive layer (not shown) included in the first electrode functional layer 2 and the second conductive layer (not shown) included in the intermediate functional layer 4 can be combined with an n-type layer, a p-type layer, a p+ type layer, a p++ type layer, etc. according to the characteristics of the first photoactive layer 3 and the purpose of improving the carrier collection efficiency. Specifically, when p-type silicon is used as the first photoactive layer 3, a phosphorus-doped silicon film (n-layer) can be combined as the second conductive layer and a p+ layer as the first conductive layer.

[0041] Figure 1 The multilayer coupling type photoelectric conversion element 1 shown has two photoactive layers 3 and 5, and adopts a tandem solar cell having a structure in which a cell having the second photoactive layer 5 is used as a top cell, and a cell having the first photoactive layer 3 is used as a bottom cell, and they are connected in series via an intermediate functional layer 4. The first electrode functional layer 2 and the second electrode functional layer 6 serve as an anode or a cathode, from which the electric energy generated by the element is extracted.

[0042] exist Figure 1 In the multilayer coupling type photoelectric conversion element 1 shown, a part of the layer 6b included in the second electrode functional layer 6 is extended and stacked on the end surface 7a so as to cover the end 5a of the second photoactive layer 5. The end 5a of the second photoactive layer 5 is covered by the part of the layer 6b included in the second electrode functional layer 6. As a result, water does not adhere to the second photoactive layer 5 from the outside of the element 1, and the photoactive material having a perovskite type crystal structure constituting the second photoactive layer 5 is not decomposed by water. As a result, a short circuit of the top unit can be prevented.

[0043] In addition, not limited to Figure 1 In the example shown, a portion of the layer 6b included in the second electrode functional layer 6 may be laminated by extending on the end surface 7a so as to cover the end 3a of the first photoactive layer 3. Water may use the interface between the end 7a of the laminate 7 and the portion of the layer 6b included in the second electrode functional layer 6 as an intrusion path, but by extending the portion of the layer 6b included in the second electrode functional layer 6 to the first photoactive layer 3, the intrusion path of water becomes longer, and the possibility of water intruding from the outside of the element 1 to the second photoactive layer 5 can be further reduced.

[0044] (Second Embodiment)

[0045] Figure 2 A multilayer coupling type photoelectric conversion element 200 according to the second embodiment is shown. Figure 2 The multilayer coupling type photoelectric conversion element 200 shown is composed of a stacked body 207 in which a first electrode functional layer 202, a first photoactive layer 203 composed of crystalline silicon, an intermediate functional layer 204, a second photoactive layer 205 composed of a photoactive material having a perovskite crystal structure, and a second electrode functional layer 206 are stacked. Figure 2 In the multilayer coupling type photoelectric conversion element 200 shown, the light receiving surfaces of the first photoactive layer 203 and the second photoactive layer 205 are set to be surfaces on the second electrode functional layer 206 side.

[0046] The end 202a of the first electrode functional layer 202, the end 203a of the first photoactive layer 203, the end 204a of the intermediate functional layer 204, the end 205a of the second photoactive layer 205, and the end 206a of the second electrode functional layer 206 are located at the end surface 207a of the stack 207. In addition, a part of the layer included in the second electrode functional layer 206 (hereinafter referred to as the covering layer 206b) is stacked inside the stack 207 and extends and is stacked in a manner covering a part of the end surface 207a of the stack 207.

[0047] Hereinafter, the structure of the stacked body 207 of the multilayer coupling type photoelectric conversion element 200 according to the present embodiment will be described in order.

[0048] The first electrode functional layer 202 has a first electrode 202b, a passivation film 202c, and a first conductive layer 202d.

[0049] The first electrode 202b is formed so as to cover the entire surface of the first photoactive layer 203. The first electrode 202b functions as an electrode and can also function as a reflective layer that reflects incident light. That is, the light that cannot be absorbed by the first photoactive layer 203 and the second photoactive layer 205 can be reflected and absorbed again by the first photoactive layer 203 and the second photoactive layer 205, and as a result, the amount of current generated can be increased.

[0050] The first electrode 202b may be selected from any material known in the art as long as it has conductivity. The material of the first electrode 202b may be gold, silver, copper, platinum, aluminum, titanium, iron, palladium, etc., preferably aluminum or silver. In particular, aluminum is preferred from the perspectives of light reflectivity and cost.

[0051] The thickness of the first electrode 202 b is preferably 10 nm to 10000 nm, more preferably 15 nm to 1000 nm, and particularly preferably 20 nm to 300 nm.

[0052] The passivation film 202c is disposed between the first photoactive layer 203 and the first electrode 202b. The passivation film 202c electrically insulates the first photoactive layer 203 from the first electrode 202b, but has an opening 202e, through which the first conductive layer 202d ensures electrical connection between the first photoactive layer 203 and the first electrode 202b. Therefore, the region where the carriers may move is limited, so that the carriers can be collected efficiently.

[0053] The material used to form the passivation film 202c is not particularly limited. Specifically, examples thereof include a silicon oxide film formed by thermally oxidizing the surface of a silicon material, and an AlOx, SiNx, or other film formed by plasma-enhanced chemical vapor deposition (PECVD) or plasma-assisted atomic layer deposition (PAALD).

[0054] The first conductive layer 202d is a layer disposed between the first photoactive layer 203 and the first electrode 202b. The first conductive layer 202d can be combined with the second conductive layer 204a described later, according to the characteristics of the first photoactive layer 203, according to the purpose of improving the carrier collection efficiency, etc., to form an n-type layer, a p-type layer, a p+ type layer, a p++ type layer, etc. For example, when p-type silicon is used as the first photoactive layer 203, the first conductive layer 202d is set as a p+ layer, and the second conductive layer 204a is set as a phosphorus-doped silicon film (n layer). The first conductive layer 202d is formed by doping Al in the first photoactive layer 203, for example, when p-type silicon is used as the first photoactive layer 203.

[0055] The first photoactive layer 203 may be the same as the first photoactive layer 3 described in Embodiment 1. The thickness of the first photoactive layer 203 is preferably 50 μm to 500 μm, and more preferably 100 μm to 300 μm.

[0056] The intermediate functional layer 204 includes a second conductive layer 204 a in contact with the first photoactive layer 203 , a transparent conductive layer 204 b , and a first functional layer 204 c in contact with the second photoactive layer 205 .

[0057] The second conductive layer 204a is a layer disposed between the first photoactive layer 203 and the transparent conductive layer 204b. The second conductive layer 204a can be formed, for example, by introducing a dopant required for amorphous silicon (a-Si). That is, for example, silicon is deposited by a PECVD method to form an a-Si layer, and then phosphorus is doped to form the second conductive layer 204a composed of an n-type silicon layer. Alternatively, phosphorus may be doped in the introduced gas when the a-Si layer is deposited by a PECVD method.

[0058] By reducing the thickness of the second conductive layer 204a, the carrier generation region can be further limited, and thus the amount of generated current can be further increased. Specifically, the thickness of the second conductive layer 204a is preferably 1 nm to 10 nm, and more preferably 2 nm to 4 nm.

[0059] The transparent conductive layer 204b is arranged in contact with the second conductive layer 204a. The transparent conductive layer 204b has the function of isolating and electrically connecting the bottom unit mainly composed of the first photoactive layer 203 and the top unit mainly composed of the second photoactive layer 205, and guiding the light not absorbed by the second photoactive layer 205 to the first photoactive layer 203.

[0060] The material of the transparent conductive layer 204b can be selected from transparent or translucent conductive materials. As such a material, a conductive metal oxide film can be cited. Specifically, indium oxide, zinc oxide, tin oxide, and indium tin oxide (ITO), indium zinc oxide (IZO) and the like as their composites can be used. The transparent conductive layer 204b composed of such metal oxides can be formed by a generally known method. Specifically, it can be formed by sputtering.

[0061] The total thickness of the transparent conductive layer 204b is preferably 5nm to 70nm. If it is thinner than 5nm, there are many film defects and the isolation of the layer adjacent to the transparent conductive layer 204b is insufficient. If it is thicker than 70nm, the light transmittance is reduced due to the diffraction effect, which sometimes leads to a reduction in the power generation on the first photoactive layer side.

[0062] The first functional layer 204c exists between the transparent conductive layer 204b and the second photoactive layer 205. The first functional layer 204c is a layer that transports electrons or preferentially extracts holes together with the second functional layer 206d described later, and functions as a hole transport layer or an electron transport layer.

[0063] The second photoactive layer 205 may be the same as the second photoactive layer 5 described in the first embodiment. If the thickness of the second photoactive layer 205 is increased, the light absorption amount increases and the short-circuit current density (Jsc) increases, but there is a tendency that the loss caused by deactivation increases the amount of carrier transport distance increase. Therefore, in order to obtain the maximum efficiency, it has an optimal thickness. Specifically, the thickness of the second photoactive layer 205 is preferably 30nm to 1000nm, and more preferably 60nm to 600nm.

[0064] The second electrode functional layer 206 includes a second metal electrode 206c, a second transparent electrode 206e, and a second functional layer 206d. The second functional layer 206d is a partial layer included in the second electrode functional layer 206. In addition, a portion of the second electrode functional layer 206 is laminated on the end surface 207a of the laminate 207 as a covering layer 206b so as to cover the end 205a of the second photoactive layer 205.

[0065] The second electrode functional layer 206 is disposed on the light incident surface side. Figure 2 In the embodiment, the second metal electrode 206c and the second transparent electrode 206e have different characteristics, and therefore, one of them may be used or a combination of them may be used depending on the characteristics.

[0066] The second transparent electrode 206e is a transparent or semi-transparent conductive layer. The second transparent electrode 206e may also have a structure in which a plurality of materials are stacked. In addition, since the transparent electrode transmits light, it can be formed on the entire surface of the stack.

[0067] As the material of the second transparent electrode 206e, conductive metal oxide films, semi-transparent metal films, etc. can be cited. Specifically, films (NESA, etc.), aluminum, gold, platinum, silver, copper, etc. made of conductive glass composed of indium oxide, zinc oxide, tin oxide and their complexes, i.e., indium tin oxide (ITO), indium zinc oxide (IZO), fluorine-doped tin oxide (FTO), indium zinc oxide, etc. are used. In particular, metal oxides such as ITO or IZO are preferred. The second transparent electrode 206e composed of such metal oxides can be formed by a commonly known method. Specifically, it is formed by sputtering.

[0068] The thickness of the second transparent electrode 206e is preferably 30nm to 300nm. If the thickness of the second transparent electrode 206e is thinner than 30nm, there is a tendency for the conductivity to decrease and the resistance to increase. If the resistance increases, it may sometimes become a cause of reduced photoelectric conversion efficiency. On the other hand, if the thickness of the second transparent electrode 206e is thicker than 300nm, there is a tendency for the flexibility of the electrode to decrease. As a result, when the thickness is thicker, there is a situation where cracks will occur if stress acts. The second transparent electrode 206e can be a single-layer structure or a multilayer structure in which layers composed of materials with different work functions are stacked.

[0069] The second metal electrode 206 c only needs to be conductive, and specifically, a conductive material such as gold, silver, copper, platinum, aluminum, titanium, iron, palladium, etc. can be used.

[0070] The second metal electrode 206c has a shape in which a plurality of metal wires are arranged substantially in parallel. The thickness of the second metal electrode 206c is preferably, for example, 30 nm to 300 nm. If the thickness of the second metal electrode 206c is thinner than 30 nm, there is a tendency for the conductivity to decrease and the resistance to increase. If the resistance increases, it may sometimes cause a decrease in the photoelectric conversion efficiency. If the thickness of the second metal electrode 206c is less than 100 nm, it is preferred because it is light-transmissive and can improve the power generation efficiency and the luminous efficiency. The second metal electrode 206c can be a single-layer structure or a multilayer structure in which layers composed of different materials are stacked.

[0071] The second functional layer 206d exists between the second transparent electrode 206e and the second photoactive layer 205. The second functional layer 206d is a layer that transports electrons or preferentially extracts holes, and functions as a hole transport layer or an electron transport layer.

[0072] When the second functional layer 206d is used as a hole transport layer or an electron transport layer, the second functional layer 206d may be formed of an inorganic oxide. When the second functional layer 206d is used as a hole transport layer, the second functional layer 206d may be formed of titanium oxide. In addition, when the second functional layer 206d is used as an electron transport layer, the second functional layer 206d may be formed of tin oxide.

[0073] When the second functional layer 206d is used as a hole injection layer, its thickness is preferably 30 nm or less, and may be 15 nm to 25 nm. This is because the film resistance of the hole injection layer can be reduced to improve the conversion efficiency. On the other hand, the thickness of the hole injection layer can be 5 nm or more.

[0074] When the second functional layer 206d is used as an electron transport layer, its thickness is preferably less than 30 nm, and can also be 15 nm to 25 nm. This is because it can reduce the film resistance of the electron transport layer and improve the conversion efficiency. On the other hand, the thickness of the electron transport layer can be set to 5 nm or more.

[0075] The covering layer 206b, which is a part of the second functional layer 206d, is stacked on the end surface 207a of the stacked body 207. The covering layer 206b covers the end 205a of the second photoactive layer 205. The covering layer 206b is formed integrally with the second functional layer 206d and is continuous with the second functional layer 206d. The material of the covering layer 206b is the same as that of the second functional layer 206d. That is, the covering layer 206b is composed of an inorganic oxide, more specifically, titanium oxide or tin oxide. In addition, the thickness of the covering layer 206b is equal to the thickness of the second functional layer 206d.

[0076] exist Figure 2In the multilayer coupling type photoelectric conversion element 201 shown, the second functional layer 206d is stacked inside the stack 207, and the cover layer 206b, which is a part of the second functional layer 206d, is stacked on the end surface 207a in a manner that covers the end 205a of the second photoactive layer 205. That is, the end 205a of the second photoactive layer 205 is covered by the cover layer 206b. As a result, water does not intrude into the second photoactive layer 205 from the outside of the element 201, and the photoactive material having a perovskite type crystal structure constituting the second photoactive layer 205 is not decomposed by water. As a result, a short circuit of the top unit can be prevented.

[0077] Figure 3 A modification of this embodiment is shown. Figure 3 In the multilayer coupling type photoelectric conversion element 300 shown, the cover layer 206b is stacked on the end face 207a so as to cover the end 203a of the first photoactive layer 203. Water may use the interface between the end face 207a of the stack 207 and the cover layer 206b as an intrusion path, but by extending the cover layer 206b to the first photoactive layer 203, the intrusion path of water becomes longer, and the possibility of water intruding into the second photoactive layer 205 from the outside of the element 301 can be further reduced.

[0078] (Third Embodiment)

[0079] Next, a method for manufacturing a multilayer coupling type photoelectric conversion element as a third embodiment is described. The manufacturing method of this embodiment is a manufacturing method of a modified example of the second embodiment, and includes a step of stacking a second electrode functional layer on an intermediate stack. In this step, a stacking step of forming a portion of the layers included in the second electrode functional layer by atomic layer deposition is included. In the stacking step, a portion of the layers included in the second electrode functional layer is stacked on the second photoactive layer of the intermediate stack, and at the same time, is stacked on the end of the second photoactive layer located on the end face of the intermediate stack.

[0080] like Figure 4 As shown, the intermediate stack 407 has a first electrode functional layer 202, a first photoactive layer 203 composed of crystalline silicon, an intermediate functional layer 204, and a second photoactive layer 205 composed of a photoactive material having a perovskite crystal structure.

[0081] As described in the second embodiment, the first electrode functional layer 202 includes: a first electrode 202b; a passivation film 202c disposed between the first electrode 202b and the first photoactive layer 203; and a first conductive layer 204 penetrating the passivation film 202c and electrically connecting the first electrode 202b and the second photoactive layer 203.

[0082] The first photoactive layer 203 is the same as that described in the second embodiment.

[0083] The intermediate functional layer 204 includes a second conductive layer 204 a stacked on the second photoactive layer 203 , a transparent electrode layer 204 b , and a first functional layer 204 c disposed between the transparent electrode layer 204 b and the first photoactive layer 205 .

[0084] The second photoactive layer 205 is the same as that described in the second embodiment.

[0085] The method for producing the intermediate laminate 407 does not need to be particularly limited, and the intermediate laminate 407 may be produced, for example, in the following procedure.

[0086] That is, a crystalline silicon substrate is prepared to be the first photoactive layer 203, and a passivation film 202c is formed on one surface thereof. The passivation film 202c is formed by, for example, thermally oxidizing the surface of the crystalline silicon substrate.

[0087] Next, a fire-through paste is applied to the portion where the first conductive layer 202d is to be formed, and high-temperature firing is performed at a firing temperature of 660°C to 1000°C to react the paste with the passivation film 202c to form the first conductive layer 202d. In this method, although the opening 202e is not formed in the passivation film 202c in advance, since the passivation film 202c is modified when the first conductive layer 204 is formed, in the embodiment, for convenience, the modified portion of the passivation film 202c becomes the opening 202e. In addition, the first conductive layer 202d formed by this method typically has a dome-shaped structure.

[0088] When a metal paste containing silver or aluminum is applied as a fire through paste, screen printing is preferably used. The metal paste may also contain glass powder or an organic solvent. When heat treatment is performed after printing the aluminum paste, a p+ layer (first conductive layer 202d) in which aluminum is diffused to a high concentration is formed.

[0089] Next, the second conductive layer 204a is formed on the other surface of the crystalline silicon substrate to be the first photoactive layer 203. The second conductive layer 204a can be formed by introducing a dopant required for amorphous silicon (a-Si) as described in the second embodiment.

[0090] Next, a transparent conductive layer 204b is formed on the second conductive layer 204a, and further a first functional layer 204c is formed on the transparent conductive layer 204b. The transparent conductive layer 204b and the first functional layer 204c are formed by sputtering.

[0091] Next, the second photoactive layer 205 is formed on the first functional layer 204c. From the viewpoint of cost, it is preferable to form the second photoactive layer 205 by a coating method.

[0092] That is, a coating liquid containing a precursor compound of a perovskite structure and an organic solvent capable of dissolving the precursor compound is applied to a substrate, such as the first functional layer 204c, to form a coating film. In addition, the surface of the first functional layer 204c is preferably subjected to a surface treatment in advance to obtain high wettability to the coating liquid forming the second photoactive layer 205. Specifically, UV-ozone treatment and plasma treatment can be cited.

[0093] The solvent used for the coating liquid is, for example, N,N-dimethylformamide (DMF), γ-butyrolactone, dimethyl sulfoxide (DMSO), etc. There is no limitation on the solvent as long as it can dissolve the material, and it can also be mixed. The second photoactive layer 205 can be formed by coating a single coating liquid in which all the raw materials forming the perovskite structure are dissolved in one solution. In addition, the plurality of raw materials forming the perovskite structure can be separately prepared as liquids of a plurality of solutions, a plurality of coating liquids, and they are applied sequentially. Spin coaters, slit coaters, rod coaters, dip coaters, etc. can be used for coating.

[0094] The coating liquid may further contain an additive. As such an additive, 1,8-diiodooctane (DIO) and N-cyclohexyl-2-pyrrolidone (CHP) are preferred.

[0095] The coating solution containing the precursor of the perovskite structure may also be applied more than twice. In such a case, the second photoactive layer 205 formed in the initial coating is likely to become a lattice mismatch layer, so it is preferably applied in a relatively thin thickness. The coating conditions after the second coating are, specifically, preferably a relatively fast rotation speed of the spin coater, a relatively narrow slit width of the slit coater or the rod coater, a relatively fast pulling speed of the dip coater, a relatively thin solute concentration in the coating solution, and other conditions that make the film thickness thinner.

[0096] After the perovskite structure formation reaction is completed, annealing is preferably performed to dry the solvent. This annealing is performed to remove the solvent contained in the perovskite layer, and is preferably performed before forming the next layer, such as the second functional layer 206 d , on the second photoactive layer 205 .

[0097] The intermediate laminate 407 is manufactured as described above.

[0098] Next, a step of stacking a second electrode functional layer on the second photoactive layer 205 of the intermediate stack 407 is performed. The step of stacking the second electrode functional layer includes a step of forming the second functional layer 206d and a step of forming the second transparent electrode 206e and the second metal electrode 206c.

[0099] In the process of forming the second functional layer 206d, the second functional layer 206d as a part of the second electrode functional layer is formed by atomic layer deposition. In the atomic layer deposition, a plurality of gaseous raw materials (precursors) are alternately exposed to the surface to be formed of the second functional layer 206d, thereby forming the second functional layer 204c. Thus, the second functional layer 206d is not only laminated on the upper surface of the second photoactive layer 205, but also laminated on the end surface 407a of the intermediate laminate 407.

[0100] Figure 5 4 shows the intermediate laminate 407 after the second functional layer 206d is formed. Figure 5 In the example shown, when the atomic layer deposition method is performed, the intermediate stack 407 is mounted on the jig 500. The jig 500 covers the first electrode functional layer 202. Since the first electrode functional layer 202 is covered by the jig 500, when the second functional layer 206d is formed by the atomic layer deposition method, the second functional layer 206d is formed on the second photoactive layer 205 and also formed on the portion where the first photoactive layer 203 to the second photoactive layer 205 are stacked in the end surface 207a of the intermediate stack. In this way, the second functional layer 206d including the cover layer 206b is formed.

[0101] Then, if Figure 6 As shown, the second transparent electrode 206e and the second metal electrode 206c are formed by sputtering, for example. Figure 3 The multilayer coupling type photoelectric conversion element 300 is shown.

[0102] According to the manufacturing method of this embodiment, the second functional layer 206d is formed by atomic layer deposition, so that the covering layer 204b covering at least the end of the second photoactive layer 205 can be formed simultaneously with the formation of the second functional layer 206d, thereby simplifying the process.

[0103] Furthermore, when the second functional layer 206d is formed by atomic layer deposition, the jig 500 covering at least the first electrode functional layer 202 is attached to the intermediate stack 407, so that the second functional layer 206d is not stacked on the first electrode functional layer 202. Thus, the second transparent electrode 206e and the first electrode 202b of the multilayer coupling type photoelectric conversion element 300 are not short-circuited.

[0104] In addition, in manufacturing Figure 2 In the case of the multilayer coupled photoelectric conversion element 200 shown, instead of the above-mentioned clamp 500, a clamp is used that covers the end face 407a of the intermediate stack 407 except for the end of the second photoactive layer 205. While the clamp is installed on the intermediate stack, the second functional layer 206d can be formed by atomic layer deposition.

[0105] (Fourth Embodiment)

[0106] Next, a multilayer coupling type photoelectric conversion element according to a fourth embodiment and a method for manufacturing the same will be described.

[0107] Figure 7 The multilayer coupling type photoelectric conversion element 601 shown is composed of a stacked body 607 formed by stacking a first electrode functional layer 602, a first photoactive layer 603 composed of crystalline silicon, an intermediate functional layer 604, a second photoactive layer 605 composed of a photoactive material having a perovskite type crystal structure, and a second electrode functional layer 606. Figure 7 In the multilayer coupling type photoelectric conversion element 601 shown, the light receiving surfaces of the first photoactive layer 603 and the second photoactive layer 605 are set to be surfaces on the second electrode functional layer 606 side.

[0108] An end 603 a of the first photoactive layer 603 , an end 604 a of the intermediate functional layer 604 , an end 605 a of the second photoactive layer 605 , and an end 606 a of the second electrode functional layer 606 are located on an end surface 607 a of the stack 607 .

[0109] Figure 7 In the multilayer coupling type photoelectric conversion element 601 shown, a part of the layer 606b included in the second electrode functional layer 606 is stacked inside the stack 607 and is stacked so as to extend and cover at least the entire end surface 7a of the stack 607. Figure 7 In the example shown, the partial layer 606b included in the second electrode functional layer 606 covers the entire end surface 607a of the stack 607 and is formed to cover a portion of the lower surface 603b of the first photoactive layer 603. However, the partial layer 606b is not in contact with the first electrode functional layer 602.

[0110] like Figure 7 As shown, the first electrode functional layer 602 is formed in a strip shape. Figure 7 In the figure, the first electrode functional layer 602 is represented as a strip-shaped first electrode functional layer 602 having a cross section orthogonal to its length direction.

[0111] The first photoactive layer 603 , the intermediate functional layer 604 , and the second photoactive layer 605 may be the same as the first photoactive layer 3 , the intermediate functional layer 4 , and the second photoactive layer 5 of the first embodiment.

[0112] The second electrode functional layer 606 may include a second electrode 606c and a second functional layer 606d disposed between the second electrode 606c and the second photoactive layer 605. The second functional layer 606d is laminated as a partial layer 606b included in the second electrode functional layer 606 to cover at least the end surface 607a of the laminate 607.

[0113] Figure 1 The multilayer coupling type photoelectric conversion element 1 shown has two photoactive layers 603 and 605, and adopts a tandem solar cell having a structure in which a unit having the second photoactive layer 605 is used as a top unit, and a unit having the first photoactive layer 603 is used as a bottom unit, and they are connected in series via an intermediate functional layer 604. The first electrode functional layer 602 and the second electrode functional layer 606 serve as an anode or a cathode, from which the electric energy generated by the element is extracted.

[0114] exist Figure 7 In the multilayer coupling type photoelectric conversion element 601 shown, a part of the layer 606b included in the second electrode functional layer 606 is stacked so as to cover at least the end face 607a of the stacked body 607. The end 605a of the second photoactive layer 605 is covered by the part of the layer 606b included in the second electrode functional layer 606. As a result, water does not intrude into the second photoactive layer 605 from the outside of the element 601, and the photoactive material having a perovskite type crystal structure constituting the second photoactive layer 605 is not decomposed by water. As a result, a short circuit of the top unit can be prevented.

[0115] In addition, a part of the layer 606b included in the second electrode functional layer 606 is stacked in a manner that covers at least the entire end surface 607a of the stacked body 607, thereby lengthening the intrusion path of moisture to the second photoactive layer 605, thereby greatly limiting the intrusion of moisture, and reducing the possibility that the photoactive material constituting the second photoactive layer 605 will be decomposed by water. As a result, short circuits in the top unit can be more reliably prevented.

[0116] Next, refer to Figure 8 to Figure 10 ,right Figure 7 A method for manufacturing the multilayer coupling type photoelectric conversion element 601 shown in FIG. 6 is described below.

[0117] The manufacturing method of this embodiment includes a process of laminating a second electrode functional layer on an intermediate stack. In this process, a laminating process of forming a part of the layer included in the second electrode functional layer by atomic layer deposition is included. In the laminating process, a part of the layer included in the second electrode functional layer is laminated on the second photoactive layer of the intermediate stack, and is laminated on the end of the second photoactive layer located on the end face of the intermediate stack. In particular, in the laminating process of this embodiment, a part of the layer included in the second electrode functional layer is laminated on the second photoactive layer of the intermediate stack, and is laminated on at least the entire surface of the end face of the intermediate stack. Furthermore, in the laminating process, a part of the layer included in the second electrode functional layer can also be laminated on a part of the lower surface 603b of the first electrode functional layer 602 side of the first photoactive layer.

[0118] like Figure 8 As shown, the intermediate stack 707 has a first electrode functional layer 602, a first photoactive layer 603 composed of crystalline silicon, an intermediate functional layer 604, and a second photoactive layer 605 composed of a photoactive material having a perovskite-type crystal structure.

[0119] The method for producing the intermediate laminate 407 is not particularly limited, and the intermediate laminate 407 may be produced, for example, in the following procedure.

[0120] Specifically, a crystalline silicon substrate to be the first photoactive layer 603 is prepared, and the first electrode functional layer 602 is formed on one side thereof. Next, the intermediate functional layer 604 and the second photoactive layer 605 having a perovskite crystal structure are sequentially stacked on the other side of the crystalline silicon substrate to be the first photoactive layer 603.

[0121] The intermediate functional layer 604 is preferably produced by, for example, a sputtering method. In addition, the second photoactive layer 605 is preferably formed by, for example, a coating method as described in the third embodiment from the viewpoint of cost.

[0122] The intermediate laminate 707 is manufactured as described above.

[0123] Next, a step of stacking a second electrode functional layer on the second photoactive layer 605 of the intermediate stack 707 is performed. The step of stacking the second electrode functional layer includes a step of forming the second functional layer 606d and a step of forming the second electrode 606c.

[0124] like Fig. 9 As shown, in the process of forming the second functional layer 606d, after the jig 800 is mounted on the intermediate stack 707, the second functional layer 606d constituting a part of the second electrode functional layer 606 is formed by atomic layer deposition. In the atomic layer deposition method, a plurality of gaseous raw materials (precursors) are alternately exposed to the surface to be formed of the second functional layer 606d, thereby forming the second functional layer 606d. Thus, the second functional layer 606d is formed on the upper surface of the second photoactive layer 605, and a part 606b thereof is also stacked on the end surface 607a of the intermediate stack 707 and a part of the lower surface 603b of the first photoactive layer 603.

[0125] The jig 800 is a hollow box-shaped jig that covers the first electrode functional layer 602 and is in contact with the lower surface 603b of the first photoactive layer 603. Since the first electrode functional layer 602 is covered by the jig 800, when the second functional layer 606d is formed by the atomic layer deposition method, the second functional layer 606d is not bonded to the first electrode functional layer 602 but is formed on the second photoactive layer 605, and a portion 606b thereof is formed on the entire end surface 707a of the intermediate stack 707 and a portion of the lower surface 603b of the first photoactive layer 603. In this way, the second functional layer 206d is formed.

[0126] The range of laminating the second functional layer 606d and the portion 606b thereof can be adjusted by changing the shape of the jig 800. For example, as another example of a jig, by using a jig that covers the entire lower surface 603b of the first electrode functional layer 602 and the first photoactive layer 603, the second functional layer 606d and the portion 606b thereof can be laminated in a manner that covers the entire surface of the second photoactive layer 605 and the end surface 707a of the intermediate stack 707.

[0127] Then, if Fig.10 As shown, the second electrode 606c is formed by, for example, sputtering. Figure 7 The multilayer coupling type photoelectric conversion element 601 is shown.

[0128] According to at least one embodiment described above, by having a covering layer stacked on the end surface so as to cover the end of the second photoactive layer located on the end surface of the stack, water can be prevented from contacting the second photoactive layer composed of a photoactive material having a perovskite crystal structure.

[0129] Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the subject matter of the invention. These embodiments and their variations are included in the scope or subject matter of the invention, and are included in the invention described in the claims and the scope of their equivalents.

[0130] [Explanation of Reference Numerals]

[0131] 1…Multilayer coupling type photoelectric conversion element, 2…First electrode functional layer, 3…First photoactive layer, 4…Intermediate functional layer, 5…Second photoactive layer, 6…Second electrode functional layer, 6a…End of the second photoactive layer, 6b…Part of the layer included in the second electrode functional layer, 6c…Second electrode, 6d, 206d…Second functional layer, 7…Layer, 7a…End surface of the layer, 202b…First electrode, 202c…Passivation film, 202d…First conductive layer, 204a…Second conductive layer, 204b…Transparent electrode layer, 204c…First functional layer, 407…Intermediate laminate, 500…Jack.

Claims

1. A multi-layer coupling type photoelectric conversion element, characterized in that: The multilayer coupling type photoelectric conversion element is composed of a stacked body, wherein the stacked body is formed by stacking a first electrode functional layer, a first photoactive layer composed of crystalline silicon, an intermediate functional layer, a second photoactive layer composed of a photoactive material having a perovskite type crystal structure, and a second electrode functional layer. The second electrode functional layer is composed of a second functional layer stacked on the second photoactive layer and functioning as a hole injection layer or an electron transport layer, and a second electrode stacked on the second functional layer. The second functional layer is stacked inside the stacked body, and is stacked so as to extend on the end surface so as to entirely cover the end portion of the second photoactive layer located on the end surface of the stacked body.

2. The multilayer coupling type photoelectric conversion element according to claim 1, characterized in that: The second functional layer is stacked on the end surface and extends all the way to the first photoactive layer.

3. The multilayer coupling type photoelectric conversion element according to claim 1, characterized in that: The second functional layer is laminated so as to cover the entire end surface of the laminate.

4. The multilayer coupling type photoelectric conversion element according to claim 1, characterized in that: The second functional layer is stacked so as to cover the entire end surface of the stacked body and to cover a portion of the surface of the first photoactive layer on the first electrode functional layer side.

5. The multilayer coupling type photoelectric conversion element according to claim 1, characterized in that: The first electrode functional layer comprises: a first electrode; a passivation film disposed between the first electrode and the first photoactive layer; and a first conductive layer penetrating the passivation film and electrically connecting the first electrode and the first photoactive layer. The intermediate functional layer comprises: a second conductive layer stacked on the first photoactive layer; a transparent electrode layer; and a first functional layer disposed between the transparent electrode layer and the second photoactive layer. The second functional layer is stacked between the second photoactive layer and the second electrode, and is stacked so as to extend on the end surface so as to cover the end portion of the second photoactive layer located on the end surface of the stack.

6. A method for manufacturing a multilayer coupling type photoelectric conversion element, characterized in that: The method comprises the steps of: preparing an intermediate stack having a first electrode functional layer, a first photoactive layer composed of crystalline silicon, an intermediate functional layer, and a second photoactive layer composed of a photoactive material having a perovskite crystal structure, and stacking the second electrode functional layer on the second photoactive layer of the intermediate stack; The above process includes a lamination process of forming a part of the layers included in the second electrode functional layer by atomic layer deposition. In the stacking process, while the intermediate stack is installed on a fixture that covers at least the first electrode functional layer, a portion of the layer included in the second electrode functional layer is stacked on the second photoactive layer of the intermediate stack, and is stacked on the end of the second photoactive layer located on the end face of the intermediate stack.

7. The method for manufacturing a multilayer coupling type photoelectric conversion element according to claim 6, characterized in that: In the stacking process, while the intermediate stack is installed on a fixture that covers at least the first electrode functional layer, a portion of the layer included in the second electrode functional layer is stacked on the second photoactive layer of the intermediate stack, and the stacking is performed in a manner that covers the entire end surface of the intermediate stack.

8. The method for manufacturing a multi-layer coupling type photoelectric conversion element according to claim 6, characterized in that: In the stacking process, while the intermediate stack is installed on a fixture that covers at least the first electrode functional layer, a portion of the layer included in the second electrode functional layer is stacked on the second photoactive layer of the intermediate stack, and the stacking is performed in a manner that covers the entire end surface of the intermediate stack and covers a portion of the surface of the first photoactive layer on the first electrode functional layer side.

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