All-perovskite laminated cell and preparation method thereof

Abstract

The invention provides a full-perovskite laminated cell and a preparation method thereof, the full-perovskite laminated cell sequentially comprises a wide-band-gap perovskite top cell, a tunneling layer and a narrow-band-gap perovskite bottom cell from a light incident surface, the tunneling layer is prepared by adopting a reaction plasma deposition method, and the tunneling layer is made of a transparent conductive metal oxide. The full-perovskite laminated cell prepared by the invention is high in efficiency and stability.

Description

Technical Field

[0001] The present invention belongs to the field of solar cells, and in particular relates to a full perovskite stacked cell and a preparation method thereof. Background Art

[0002] Organic and inorganic metal halide perovskite materials are used as the light-absorbing layer of solar cells due to their excellent photoelectric properties and low cost. At the same time, since the band gap of perovskite materials is adjustable, they can be stacked with other photovoltaic materials with different band gaps, such as crystalline silicon materials, copper indium gallium selenide materials, perovskite materials, cadmium telluride materials, gallium arsenide materials, organic photovoltaic materials, etc. to form a stacked solar cell, achieving extremely high photoelectric conversion efficiency. Among all such stacked cells, all-perovskite stacked cells are considered to be the ultimate solution for future stacked cells due to their low material cost and compatible flexible preparation.

[0003] All the high-performance all-perovskite tandem cell structures reported at this stage contain a layer of SnO prepared by atomic layer deposition (ALD) between the tunneling layer and the electron transport layer. 2 The buffer layer mainly serves as a buffer layer for sputtering damage and a solvent barrier layer to ensure that the previously prepared perovskite film will not be dissolved during the preparation of the second perovskite layer, thereby protecting the perovskite film layer.

[0004] But atomic layer deposition SnO 2 Layer (ALD-SnO 2 ) has problems such as long preparation time, difficulty in large-scale preparation, extremely high cost, and poor stability. Specifically, they include: (1) ALD-SnO 2 It can be prepared by using ALD equipment of both time type and space type. When preparing large-area all-perovskite tandem battery components at the square meter level, the time type growth time is too long, which seriously affects the photoelectric conversion efficiency and production cycle of the device. The space type ALD is not dense enough and it is difficult to block the solvent. It is easy to dissolve when preparing the next layer of perovskite, resulting in the inability to prepare the tandem battery device; (2) ALD-SnO 2 The raw material is TDMASn, which costs 600 yuan / g. Its raw material cost accounts for more than 10% of the total cost of perovskite stacked cells. (3) ALD-SnO 2 The TDMASn source will react with the components in the perovskite to form a thin defect layer, affecting the stability.

[0005] Therefore, there is an urgent need to develop an all-perovskite tandem cell that does not contain a buffer layer in the tunneling layer and electron transport layer with low preparation cost, high photoelectric conversion efficiency and good stability. Summary of the invention

[0006] In order to solve the problems existing in the prior art, the present invention provides an all-perovskite tandem cell and a preparation method thereof. The present invention adopts a reactive plasma deposition method to prepare a tunneling layer, and the tunneling layer and electron transport layer of the prepared all-perovskite tandem cell do not contain a buffer layer. The present invention has low production cost, fast preparation speed of the perovskite film, and the all-perovskite tandem cell has good photoelectric conversion efficiency and stability.

[0007] The present invention provides an all-perovskite stacked cell, which comprises a wide-bandgap perovskite top cell, a tunneling layer and a narrow-bandgap perovskite bottom cell in sequence from the light incident surface, wherein the tunneling layer is prepared by a reactive plasma deposition method, and the material of the tunneling layer is a transparent conductive metal oxide.

[0008] In one or more embodiments, the transparent conductive metal oxide is selected from one or more of tungsten-doped indium oxide, indium zinc oxide, indium oxide, indium tin oxide, cerium-doped indium oxide, zirconium-doped indium oxide, and gallium zinc-doped indium oxide.

[0009] In one or more embodiments, the tunneling layer has a thickness of 5-100 nm.

[0010] The all-perovskite stacked cell includes an upright all-perovskite stacked cell and an inverted all-perovskite stacked cell.

[0011] In one or more embodiments, in the upright all-perovskite stack cell, the wide-bandgap perovskite top cell includes, from the light incident side, a substrate, a transparent electrode layer, a hole transport layer, a wide-bandgap perovskite layer, and an electron transport layer; the narrow-bandgap perovskite bottom cell includes, from the light incident side, a hole transport layer, a narrow-bandgap perovskite layer, an electron transport layer, a buffer layer A, and a metal electrode layer.

[0012] In one or more embodiments, in the inverted all-perovskite stack cell, the wide-bandgap perovskite top cell includes, from the light incident side, a transparent electrode layer, an electron transport layer, a wide-bandgap perovskite layer, and a hole transport layer; the narrow-bandgap perovskite bottom cell includes, from the light incident side, an electron transport layer, a narrow-bandgap perovskite layer, a hole transport layer, a transparent electrode layer, and a substrate.

[0013] In one or more embodiments, in the wide bandgap perovskite top cell, the bandgap width of the wide bandgap perovskite layer is 1.5-3.0 eV.

[0014] In one or more embodiments, in the wide bandgap perovskite top cell, the thickness of the wide bandgap perovskite layer is 200-2000 nm.

[0015] In one or more embodiments, in the narrow bandgap perovskite bottom cell, the bandgap width of the narrow bandgap perovskite layer is 1.0-1.5 eV.

[0016] In one or more embodiments, in the narrow bandgap perovskite bottom-top cell, the thickness of the narrow bandgap perovskite layer is 400-3000 nm.

[0017] In one or more embodiments, the chemical formula of the perovskite structure material is ABX 3 , A is a monovalent cation including one or more of cesium, rubidium, methylamine and formamidinium; B is a divalent cation including one or more of lead, copper, zinc, gallium, tin and calcium; X is a monovalent anion including one or more of iodine, bromine, chlorine, fluorine, thiocyanate, tetrafluoroborate and hexafluorophosphate.

[0018] In one or more embodiments, in the upright all-perovskite stacked cell, the buffer layer A is prepared by reactive plasma deposition, and the material of the buffer layer A is a transparent conductive metal oxide.

[0019] In one or more embodiments, in the upright all-perovskite stacked cell, the material of the buffer layer A is SnO 2 .

[0020] In one or more embodiments, the buffer layer A is prepared by reactive plasma deposition, and when the material of the buffer layer A is a transparent conductive metal oxide, the thickness of the buffer layer is 5-100 nm.

[0021] In one or more embodiments, the material of the buffer layer A is SnO 2 When the thickness of the buffer layer is 5-100 nm.

[0022] In one or more embodiments, the wide bandgap perovskite top cell of the inverted all-perovskite stack cell includes a buffer layer B, the buffer layer B is located between the transparent electrode layer and the electron transport layer, and the material of the buffer layer B is SnO 2 .

[0023] The present invention provides a method for preparing a full perovskite tandem battery, the method comprising the following steps:

[0024] (1) depositing a transparent electrode layer, a hole transport layer, a wide bandgap perovskite layer and an electron transport layer on the surface of a substrate in sequence to obtain a wide bandgap perovskite top cell;

[0025] (2) using reactive plasma deposition to deposit a tunneling layer on the surface of the electron transport layer in the wide bandgap perovskite top cell;

[0026] (3) A hole transport layer, a narrow bandgap perovskite layer, an electron transport layer, a buffer layer A and a metal electrode layer are sequentially deposited on the surface of the tunneling layer to obtain a narrow bandgap perovskite bottom cell and an upright all-perovskite stacked cell.

[0027] The present invention provides a method for preparing a full perovskite tandem battery, the method comprising the following steps:

[0028] (1') depositing a transparent electrode layer, a hole transport layer, a narrow bandgap perovskite layer and an electron transport layer on the surface of a substrate in sequence to obtain a narrow bandgap perovskite bottom cell;

[0029] (2') depositing a tunneling layer on the surface of the electron transport layer in the narrow bandgap perovskite bottom cell by reactive plasma deposition;

[0030] (3') depositing a hole transport layer, a wide bandgap perovskite layer, an electron transport layer and a transparent electrode layer on the surface of the tunneling layer in sequence, thereby obtaining a wide bandgap perovskite top cell and an inverted all-perovskite stacked cell.

[0031] In one or more embodiments, step (3') further comprises depositing a buffer layer B on the surface of the electron transport layer, and then depositing the transparent electrode layer.

[0032] In one or more embodiments, the wide bandgap perovskite layer is deposited by spin coating, doctor blade coating, evaporation, printing, spray coating, spray pyrolysis or slot coating.

[0033] In one or more embodiments, the narrow bandgap perovskite layer is deposited by spin coating, doctor blade coating, evaporation, printing, spray coating, spray pyrolysis or slot coating.

[0034] In one or more embodiments, the buffer layer A is deposited by reactive plasma deposition or atomic layer deposition.

[0035] In one or more embodiments, the buffer layer B is deposited by atomic layer deposition.

[0036] In one or more embodiments, the transparent electrode layer may be deposited by reactive plasma deposition, magnetron sputtering, electron beam evaporation, or thermal evaporation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 (a) is a schematic diagram of the structure of an upright all-perovskite tandem cell according to some embodiments of the present invention.

[0039] Figure 1 (b) is a schematic diagram of the structure of an inverted all-perovskite stack cell according to some embodiments of the present invention.

[0040] Figure 2 (a) is a schematic diagram of the structure of the upright all-perovskite stacked cell prepared in Comparative Example 1 of the present invention.

[0041] Figure 2 (b) is a schematic diagram of the structure of the upright all-perovskite stacked cell prepared in Example 1 of the present invention.

[0042] Figure 2 (c) is a schematic diagram of the structure of the upright all-perovskite stacked cell prepared in Example 2 of the present invention.

[0043] Figure 3 (a) is a schematic diagram of the structure of the inverted all-perovskite stacked cell prepared in Comparative Example 2 of the present invention.

[0044] Figure 3 (b) is a schematic diagram of the structure of the inverted all-perovskite stacked cell prepared in Example 3 of the present invention.

[0045] Figure 3 (c) is a schematic diagram of the structure of the inverted all-perovskite stacked cell prepared in Example 4 of the present invention. DETAILED DESCRIPTION

[0046] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0047] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0048] Herein, “comprising”, “including”, “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of”. For example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to be disclosed herein.

[0049] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0050] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0051] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0052] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0053] The present invention provides a full perovskite tandem cell, which includes a wide bandgap perovskite top cell, a tunneling layer and a narrow bandgap perovskite bottom cell in sequence from the light incident surface, the tunneling layer is prepared by a reactive plasma deposition method, and the material of the tunneling layer can be a transparent conductive metal oxide. The present invention uses a reactive plasma deposition method to deposit a transparent conductive metal oxide to prepare the tunneling layer, and the prepared tunneling layer and electron transport layer of the full perovskite tandem cell do not contain a buffer layer. The present invention has low production cost, fast preparation speed of the perovskite film, and good photoelectric conversion efficiency and stability of the full perovskite tandem cell.

[0054] In the present invention, the transparent conductive metal oxide may be selected from tungsten-doped indium oxide (IWO), indium zinc oxide (IZO), indium oxide (In 2 O 3 ), indium tin oxide (ITO), cerium-doped indium oxide (ICO), zirconium-doped indium oxide (IZrO) and gallium zinc-doped indium oxide (IGZO) One or more.

[0055] In the present invention, the thickness of the tunneling layer can be 5-100 nm, for example, 5 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, and 100 nm.

[0056] In the present invention, the all-perovskite tandem cell may include an upright all-perovskite tandem cell and an inverted all-perovskite tandem cell.

[0057] In the upright all-perovskite stacked cell of the present invention, the wide-bandgap perovskite top cell can include a substrate, a transparent electrode layer, a hole transport layer, a wide-bandgap perovskite layer and an electron transport layer in sequence from the light incident side; the narrow-bandgap perovskite bottom cell can include a hole transport layer, a narrow-bandgap perovskite layer, an electron transport layer, a buffer layer A and a metal electrode layer in sequence from the light incident side.

[0058] In the inverted all-perovskite stacked cell of the present invention, the wide-bandgap perovskite top cell can include a transparent electrode layer, an electron transport layer, a wide-bandgap perovskite layer and a hole transport layer in sequence from the light incident side; the narrow-bandgap perovskite bottom cell can include an electron transport layer, a narrow-bandgap perovskite layer, a hole transport layer, a transparent electrode layer and a substrate in sequence from the light incident side.

[0059] In the present invention, the substrate can be glass, a metal thin surface, a plastic film, wood or paper.

[0060] In the present invention, the material of the transparent electrode layer can be a transparent conductive metal oxide, and the transparent conductive metal oxide can be one or more selected from tungsten-doped indium oxide, indium zinc oxide, indium oxide, indium tin oxide, cerium-doped indium oxide, zirconium-doped indium oxide and gallium zinc-doped indium oxide.

[0061] In the present invention, the thickness of the transparent electrode layer can be 10-120 nm, for example, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 110 nm, and 120 nm.

[0062] In the present invention, the material of the hole transport layer can be a p-type semiconductor material; preferably, the p-type semiconductor material can be one or more selected from p-type single crystal silicon, p-type polycrystalline silicon, p-type amorphous silicon and single molecule self-assembly material; more preferably, the p-type semiconductor material can be selected from [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), benzoic acid, 4-[bis(2,4-dimethoxybiphenyl-4-yl)amino]-biphenyl-4-carboxylic acid [MC-43], 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Sprio -OMeTAD), polyethylene terephthalate (PET), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), polymer of 3-hexylthiophene (P3HT), poly(3,4-ethylenedioxythiophene) (PEDOT): polystyrene sulfonate (PSS), 2,2',7,7'-tetrakis(N,N-di-p-tolyl)amino-9,9-spirobifluorene (Spiro-TTB), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ), 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanodimethyl-p-benzoquinone (F6TCNNQ), 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC), antimony-doped tin oxide (ATO), NiOx, CuSCN, CuAlO 2、V 2 O 5 , CdS and CdSe.

[0063] In the present invention, the thickness of the hole transport layer can be 0.1-200 nm, for example, 0.5 nm, 1 nm,

[0064] 5nm, 10nm, 20nm, 30nm, 50nm, 100nm, 150nm, 200nm.

[0065] In the present invention, the chemical formula of the perovskite structure material can be ABX 3 A can be a monovalent cation, including cesium (Cs), rubidium (Rb), methylamine (CH 3 NH 3 , MA) and carbamimidyl (CH(NH)NH 2 , FA); B can be a divalent cation, including one or more of lead (Pb), copper (Cu), zinc (Zn), gallium (Ga), tin (Sn) and calcium (Ca); X can be a monovalent anion, including iodine (I), bromine (Br), chlorine (Cl), fluorine (F), thiocyanate ion (SCN-), tetrafluoroborate ion (BF 4 -) and hexafluorophosphate ion (PF 6 -) in one or more.

[0066] In the wide bandgap perovskite top cell of the present invention, the bandgap width of the wide bandgap perovskite layer can be 1.5-3.0 eV, for example, 1.5 eV, 1.8 eV, 2.1 eV, 2.4 eV, 2.7 eV, 3.0 eV.

[0067] In the wide bandgap perovskite top cell of the present invention, the thickness of the wide bandgap perovskite layer can be 200-2000nm, for example, 200nm, 400nm, 600nm, 800nm, 1000nm, 1200nm, 1400nm, 1600nm, 1800nm, 2000nm.

[0068] In the narrow-bandgap perovskite bottom cell of the present invention, the bandgap width of the narrow-bandgap perovskite layer can be 1.0-1.5 eV, for example, 1.0 eV, 1.1 eV, 1.2 eV, 1.3 eV, 1.4 eV, 1.5 eV.

[0069] In the narrow-bandgap perovskite bottom-top cell of the present invention, the thickness of the narrow-bandgap perovskite layer can be 400-3000nm, for example, 400nm, 600nm, 800nm, 1000nm, 1200nm, 1400nm, 1600nm, 1800nm, 2000nm, 2200nm, 2400nm, 2600nm, 2800nm, and 3000nm.

[0070] In the present invention, the electron transport layer may be made of an n-type semiconductor material; preferably, the n-type semiconductor material may be selected from n-type single crystal silicon, n-type polycrystalline silicon, n-type amorphous silicon, TiO 2 SnO 2 、ZnO、ZrO 2 , Nb x O y , Gallium-doped zinc oxide (GZO), Indium zinc oxide (IZO), Fluorine-doped tin oxide (FTO), Indium tin oxide (ITO), BaSnO 3 、TiSnO x SnZnO x and one or more of fullerenes and derivatives (C60, C70, PCBM).

[0071] In the present invention, the thickness of the electron transport layer can be 0.1-200 nm, for example, 0.5 nm, 1 nm, 5 nm, 10 nm, 20 nm, 30 nm, 50 nm, 100 nm, 150 nm, or 200 nm.

[0072] In the present invention, the material of the metal electrode layer can be gold, silver, copper, aluminum or alloys containing such metals.

[0073] In the present invention, the thickness of the metal electrode layer can be 200-30000nm, for example, 200nm, 500nm, 1000nm, 1500nm, 2000nm, 3000nm, 4000nm, 5000nm, 10000nm, 15000nm,

[0074] 20000nm, 25000nm, 30000nm.

[0075] The inverted all-perovskite stacked cell of the present invention may further include metal grid lines, and the metal grid lines are located on the surface of the transparent electrode layer.

[0076] In the present invention, the material of the metal grid line can be gold, silver, copper, aluminum or alloys containing such metals.

[0077] In the present invention, the thickness of the metal gate line can be 200-30000nm, for example, 200nm, 500nm, 1000nm, 1500nm, 2000nm, 3000nm, 4000nm, 5000nm, 10000nm, 15000nm, 20000nm, 25000nm, 30000nm.

[0078] In the upright all-perovskite stacked cell of the present invention, the buffer layer A can be prepared by a reactive plasma deposition method. In this case, the material of the buffer layer A can be a transparent conductive metal oxide.

[0079] In the present invention, the buffer layer A is prepared by reactive plasma deposition, and when the material of the buffer layer A is a transparent conductive metal oxide, the thickness of the buffer layer can be 5-100nm, for example, 5nm, 10nm, 15nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm.

[0080] In the upright all-perovskite stacked cell of the present invention, the material of the buffer layer A can be SnO 2 At this time, the thickness of the buffer layer can be 5-100nm, for example, 5nm, 10nm, 15nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, and 100nm.

[0081] The wide bandgap perovskite top cell of the inverted all-perovskite tandem cell of the present invention may include a buffer layer B or may not include a buffer layer B. Preferably, the wide bandgap perovskite top cell of the inverted all-perovskite tandem cell of the present invention may include a buffer layer B or may not include a buffer layer B.

[0082] The wide bandgap perovskite top cell of the inverted all-perovskite stacked cell of the present invention may include a buffer layer B, the buffer layer B is located between the transparent electrode layer and the electron transport layer, and the material of the buffer layer B may be SnO 2 In some embodiments, the thickness of the buffer layer B can be 5-50 nm, for example, 5 nm, 10 nm, 15 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm.

[0083] The present invention provides a method for preparing a full perovskite stacked cell, the method comprising the following steps:

[0084] (1) Depositing a transparent electrode layer, a hole transport layer, and a wide bandgap perovskite layer on the surface of the substrate in sequence

[0085] layer and electron transport layer to obtain a wide bandgap perovskite top cell;

[0086] (2) using reactive plasma deposition to deposit a tunneling layer on the surface of the electron transport layer in the wide bandgap perovskite top cell;

[0087] (3) depositing a hole transport layer, a narrow bandgap perovskite layer, an electron transport layer, a buffer layer A and a metal electrode layer on the surface of the tunneling layer in sequence to obtain a narrow bandgap perovskite bottom cell and an upright all-perovskite stacked cell; or

[0088] (1') depositing a transparent electrode layer, a hole transport layer, a narrow bandgap perovskite layer and an electron transport layer on the surface of a substrate in sequence to obtain a narrow bandgap perovskite bottom cell;

[0089] (2') depositing a tunneling layer on the surface of the electron transport layer in the narrow bandgap perovskite bottom cell by reactive plasma deposition;

[0090] (3') depositing a hole transport layer, a wide bandgap perovskite layer, an electron transport layer and a transparent electrode layer on the surface of the tunneling layer in sequence, thereby obtaining a wide bandgap perovskite top cell and an inverted all-perovskite stacked cell.

[0091] In the present invention, step (3') further comprises depositing a buffer layer B on the surface of the electron transport layer.

[0092] In the present invention, step (3') further comprises depositing metal grid lines on the surface of the transparent electrode layer.

[0093] In the present invention, the hole transport layer can be deposited by spin coating, blade coating, physical vapor deposition, atomic layer deposition, slit coating or immersion; preferably, physical vapor deposition can be magnetron sputtering, reactive plasma deposition, electron beam evaporation or thermal evaporation.

[0094] In the present invention, the electron transport layer may be deposited by spin coating, blade coating, physical vapor deposition, atomic layer deposition, slit coating or immersion; preferably, physical vapor deposition may be magnetron sputtering, reactive plasma deposition, electron beam evaporation or thermal evaporation. In the present invention, the wide bandgap perovskite layer may be deposited by spin coating, blade coating, evaporation, printing, spraying, spray pyrolysis or slit coating.

[0095] In the present invention, the deposition method of the narrow bandgap perovskite layer can be spin coating, blade coating, evaporation, printing, spray coating, spray pyrolysis or slit coating.

[0096] In the present invention, the deposition method of the buffer layer A can be reactive plasma deposition or atomic layer deposition, preferably reactive plasma deposition. In some embodiments, when the material of the buffer layer A is a transparent conductive metal oxide, the deposition method of the buffer layer A is reactive plasma deposition. The use of reactive plasma deposition to deposit the transparent conductive metal oxide is beneficial to reduce the kinetic energy of the sputtering ions sputtering to the surface of the material, thereby reducing sputtering damage, and at the same time, a dense film layer can be formed, which is beneficial to improve the photoelectric conversion efficiency and stability of the all-perovskite stacked cell.

[0097] In the present invention, the buffer layer B may be deposited by atomic layer deposition.

[0098] In the present invention, the deposition method of the transparent electrode layer can be magnetron sputtering, reactive plasma deposition, electron beam evaporation or thermal evaporation, preferably reactive plasma deposition. In some embodiments, the transparent electrode layer is deposited by reactive plasma deposition, which is beneficial to reduce the kinetic energy of sputtering ions sputtering to the surface of the material, thereby reducing sputtering damage, and can form a dense film layer, which is beneficial to improve the photoelectric conversion efficiency and stability of the all-perovskite tandem battery.

[0099] In the present invention, the metal grid lines may be deposited by thermal evaporation, printing or electroplating.

[0100] In the present invention, the metal electrode layer may be deposited by physical vapor deposition, printing, spraying or electroplating; preferably, physical vapor deposition may be magnetron sputtering, reactive plasma deposition, electron beam evaporation or thermal evaporation.

[0101] Compared with the prior art, the present invention has the following beneficial effects:

[0102] (1) The present invention has a fast preparation cycle and no high-temperature process. The perovskite does not need to be heated, and the performance of the all-perovskite stacked battery will not decay during the preparation of the tunneling layer. Therefore, the all-perovskite stacked battery has good stability;

[0103] (2) The preparation cost of the present invention is low. Taking IWO target as an example, its price is 4 yuan / g, which is much lower than the cost of ALD source;

[0104] (3) The transparent electrode layer prepared by RPD in the present invention is dense, which improves the stability of the all-perovskite stacked battery, which is better than the traditional ALD-SnO 2 Devices of buffer layers;

[0105] (4) When the buffer layer prepared by RPD is used as the buffer layer of the top electrode, the amorphous SnO layer produced by atomic layer deposition can be avoided. 2 It is difficult to prevent the diffusion of ions in the perovskite layer to the metal electrode layer, resulting in poor operating stability.

[0106] (5) The buffer layer and transparent electrode layer prepared by RPD in the present invention cause little damage to the surface film layer and can be prepared directly after the perovskite film or after C60.

[0107] The present invention will be described below in the form of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents and materials used in the examples are, unless otherwise stated, conventional methods, reagents and materials in the art. The raw material compounds in the examples can all be purchased through commercial routes.

[0108] Comparative Example 1

[0109] This comparative example was prepared Figure 2 The specific steps of the upright all-perovskite tandem cell shown in (a) are as follows:

[0110] (1) ITO was deposited on the surface of a glass substrate by magnetron sputtering to obtain a transparent electrode layer with a thickness of 110 nm, and 2PACZ was deposited on the surface of the transparent electrode layer by spin coating to obtain a hole transport layer (HTL) with a thickness of 1 nm; 1.4 mol / L FA 0.8 C s0.2 Pb(I 0.6 Br 0. 4) 3 The perovskite solution was scraped onto the hole transport layer to obtain a wide bandgap perovskite layer with a thickness of 400 nm. C60 was evaporated on the surface of the wide bandgap perovskite layer at a rate of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm. SnO was grown on the surface of the electron transport layer of the wide bandgap perovskite top cell by atomic layer deposition (ALD). 2 , a buffer layer with a thickness of 60nm is obtained, and a wide-bandgap perovskite top cell is obtained at the same time;

[0111] (2) evaporating gold on the surface of the buffer layer at a rate of 0.04 A / s to obtain a tunneling layer with a thickness of 1 nm;

[0112] (3) PSS:PEDOT was scraped onto the tunneling layer to obtain a hole transport layer with a thickness of 30 nm; 2.0 mol / L FAPb 0.5 Sn 0.5 I 3 The perovskite solution was scraped onto the hole transport layer to obtain a narrow bandgap perovskite layer with a thickness of 1.5 μm. C60 was evaporated on the surface of the narrow bandgap perovskite layer at a speed of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm. SnO was grown on the surface of the electron transport layer by atomic layer deposition. 2, a buffer layer with a thickness of 15nm was obtained; copper was evaporated on the surface of the buffer layer at a speed of 1A / s to obtain a 200nm metal electrode layer, and a narrow-bandgap perovskite bottom cell and an upright all-perovskite stacked cell were obtained at the same time.

[0113] Example 1

[0114] Preparation of this example Figure 2 (b) shows the upright all-perovskite tandem cell, and the specific steps are as follows:

[0115] (1) ITO was deposited on the surface of a glass substrate by magnetron sputtering to obtain a transparent electrode layer with a thickness of 110 nm, and 2PACZ was deposited on the surface of the transparent electrode layer by spin coating to obtain a hole transport layer with a thickness of 1 nm; 1.4 mol / L FA 0.8 C s0.2 Pb(I 0.6 Br 0. 4) 3 The perovskite solution was scraped onto the hole transport layer to obtain a wide bandgap perovskite layer with a thickness of 400 nm. C60 was evaporated on the surface of the wide bandgap perovskite layer at a speed of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm, and a wide bandgap perovskite top cell was obtained at the same time.

[0116] (2) IWO was grown on the surface of the electron transport layer of the wide bandgap perovskite top cell by reactive plasma deposition to obtain a tunneling layer with a thickness of 40 nm; during the RPD preparation process, the argon flux was 200 sccm, the deposition current was 160 A, the oxygen accounted for 15% of the total gas flow, the hydrogen accounted for 0.9% of the total gas flow, the IWO target top target rate was 0.36 mm / min, the carrier moving speed was 20 mm / s, and the preparation time was 20 min;

[0117] (3) PSS:PEDOT was scraped onto the tunneling layer to obtain a hole transport layer with a thickness of 30 nm; 2.0 mol / L FAPb 0.5 Sn 0.5 I 3 The perovskite solution was scraped on the hole transport layer to obtain a narrow bandgap perovskite layer with a thickness of 1.5 μm; C60 was evaporated on the surface of the narrow bandgap perovskite layer at a speed of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm; IWO was grown on the surface of the electron transport layer by reactive plasma deposition to obtain a buffer layer with a thickness of 15 nm; copper was evaporated on the surface of the buffer layer at a speed of 1 A / s to obtain a 200 nm metal electrode layer, and a narrow bandgap perovskite bottom cell and an upright all-perovskite stacked cell were obtained at the same time.

[0118] Example 2

[0119] Preparation of this example Figure 2 (c) shows the upright all-perovskite tandem cell, and the specific steps are as follows:

[0120] (1) ITO was deposited on the surface of a glass substrate by magnetron sputtering to obtain a transparent electrode layer with a thickness of 110 nm, and 2PACZ was deposited on the surface of the transparent electrode layer by spin coating to obtain a hole transport layer with a thickness of 1 nm; 1.4 mol / L FA 0.8 C s0.2 Pb(I 0.6 Br 0. 4) 3 The perovskite solution was scraped onto the hole transport layer to obtain a wide bandgap perovskite layer with a thickness of 400 nm. C60 was evaporated on the surface of the wide bandgap perovskite layer at a speed of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm, and a wide bandgap perovskite top cell was obtained at the same time.

[0121] (2) IWO was grown on the surface of the electron transport layer of the wide bandgap perovskite top cell by reactive plasma deposition to obtain a tunneling layer with a thickness of 40 nm; during the RPD preparation process, the argon flux was 200 sccm, the deposition current was 160 A, the oxygen accounted for 15% of the total gas flow, the hydrogen accounted for 0.9% of the total gas flow, the IWO target top target rate was 0.36 mm / min, the carrier moving speed was 20 mm / s, and the preparation time was 20 min;

[0122] (3) PSS:PEDOT was scraped onto the tunneling layer to obtain a hole transport layer with a thickness of 30 nm; 2.0 mol / L FAPb 0.5 Sn 0.5 I 3 The perovskite solution was scraped onto the hole transport layer to obtain a narrow bandgap perovskite layer with a thickness of 1.5 μm. C60 was evaporated on the surface of the narrow bandgap perovskite layer at a speed of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm. SnO was grown on the surface of the electron transport layer by atomic layer deposition. 2 , a buffer layer with a thickness of 15nm was obtained; copper was evaporated on the surface of the buffer layer at a speed of 1A / s to obtain a 200nm metal electrode layer, and a narrow-bandgap perovskite bottom cell and an upright all-perovskite stacked cell were obtained at the same time.

[0123] Comparative Example 2

[0124] This comparative example was prepared Figure 3 The inverted all-perovskite stacked cell shown in (a) has the following specific steps:

[0125] (1) ITO was sputtered on a stainless steel substrate to obtain a transparent electrode layer with a thickness of 20 nm, and 2PACZ was deposited on the surface of the transparent electrode layer by evaporation to obtain a hole transport layer with a thickness of 3 nm; 2.0 mol / L FAPb 0.5 Sn 0.5 I 3 The perovskite solution was scraped onto the hole transport layer to obtain a narrow bandgap perovskite layer with a thickness of 1.5 μm. C60 was evaporated on the surface of the narrow bandgap perovskite layer at a speed of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm. SnO was grown on the surface of the electron transport layer by atomic layer deposition. 2 , a buffer layer with a thickness of 20 nm is obtained, and a narrow bandgap perovskite bottom cell is obtained at the same time;

[0126] (2) sputtering IZO on the buffer layer surface of the narrow bandgap perovskite bottom cell at a rate of 0.3 A / s to obtain a tunneling layer with a thickness of 20 nm;

[0127] (3) Me-4PACZ was deposited on the surface of the tunneling layer by slit coating to obtain a hole transport layer with a thickness of 15 nm; 1.4 mol / L FA 0.8 C s0.2 Pb(I 0.6 Br 0. 4) 3 The perovskite solution was scraped onto the hole transport layer to obtain a wide bandgap perovskite layer with a thickness of 400 nm. C60 was evaporated on the surface of the wide bandgap perovskite layer at a speed of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm. SnO was grown on the surface of the electron transport layer by atomic layer deposition. 2 , obtaining a buffer layer with a thickness of 20nm; sputtering IZO on the surface of the buffer layer at a speed of 1A / s to obtain a transparent electrode layer with a thickness of 40nm; evaporating copper grid lines on the surface of the transparent electrode layer at a speed of 1A / s to obtain metal grid lines with a thickness of 200nm, a grid line width of 40um, and a grid line spacing of 0.6mm, and at the same time obtaining a wide-bandgap perovskite top cell and an inverted all-perovskite stacked cell.

[0128] Example 3

[0129] Preparation of this example Figure 3 (b) shows an inverted all-perovskite stacked cell, and the specific steps are as follows:

[0130] (1) ITO was sputtered on a stainless steel substrate to obtain a transparent electrode layer with a thickness of 20 nm, and 2PACZ was deposited on the surface of the transparent electrode layer by evaporation to obtain a hole transport layer with a thickness of 3 nm; 2.0 mol / L FAPb 0.5 Sn 0.5 I 3The perovskite solution was scraped onto the hole transport layer to obtain a narrow bandgap perovskite layer with a thickness of 1.5 μm; C60 was evaporated on the surface of the narrow bandgap perovskite layer at a speed of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm, and a narrow bandgap perovskite bottom cell was obtained at the same time;

[0131] (2) growing IZO on the surface of the electron transport layer of the narrow bandgap perovskite bottom cell using reactive plasma deposition to obtain a tunneling layer with a thickness of 40 nm;

[0132] (3) Me-4PACZ was deposited on the surface of the tunneling layer by slit coating to obtain a hole transport layer with a thickness of 15 nm. 1.4 mol / L FA 0.8 C s0.2 Pb(I 0.6 Br 0. 4) 3 The perovskite solution is scraped on the hole transport layer to obtain a wide bandgap perovskite layer with a thickness of 400nm; C60 is evaporated on the surface of the wide bandgap perovskite layer at a speed of 0.1A / s to obtain an electron transport layer with a thickness of 12nm; IZO is grown on the surface of the electron transport layer by reactive plasma deposition to obtain a transparent electrode layer with a thickness of 40nm; copper grid lines are evaporated on the surface of the transparent electrode layer at a speed of 1A / s to obtain metal grid lines with a thickness of 200nm, a grid line width of 40um, and a grid line spacing of 0.6mm, and a wide bandgap perovskite top cell and an inverted all-perovskite stacked cell are obtained at the same time.

[0133] Example 4

[0134] Preparation of this example Figure 3 (c) shows an inverted all-perovskite stacked cell, and the specific steps are as follows:

[0135] (1) ITO was sputtered on a stainless steel substrate to obtain a transparent electrode layer with a thickness of 20 nm, and 2PACZ was deposited on the surface of the transparent electrode layer by evaporation to obtain a hole transport layer with a thickness of 3 nm; 2.0 mol / L FAPb 0.5 Sn 0.5 I 3 The perovskite solution was scraped onto the hole transport layer to obtain a narrow bandgap perovskite layer with a thickness of 1.5 μm; C60 was evaporated on the surface of the narrow bandgap perovskite layer at a speed of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm, and a narrow bandgap perovskite bottom cell was obtained at the same time;

[0136] (2) growing IZO on the surface of the electron transport layer of the narrow bandgap perovskite bottom cell using reactive plasma deposition to obtain a tunneling layer with a thickness of 40 nm;

[0137] (3) Me-4PACZ was deposited on the surface of the tunneling layer by slit coating to obtain a hole transport layer with a thickness of 15 nm; 1.4 mol / L FA 0.8 C s0.2 Pb(I 0.6 Br 0. 4) 3 The perovskite solution was scraped onto the hole transport layer to obtain a wide bandgap perovskite layer with a thickness of 400 nm. C60 was evaporated on the surface of the wide bandgap perovskite layer at a speed of 0.1 A / s to obtain an electron transport layer with a thickness of 12 nm. SnO was grown on the surface of the electron transport layer by atomic layer deposition. 2 , obtaining a buffer layer with a thickness of 20nm; sputtering IZO on the surface of the buffer layer at a speed of 1A / s to obtain a transparent electrode layer with a thickness of 40nm; evaporating copper grid lines on the surface of the transparent electrode layer at a speed of 1A / s to obtain metal grid lines with a thickness of 200nm, a grid line width of 40um, and a grid line spacing of 0.6mm, and at the same time obtaining a wide-bandgap perovskite top cell and an inverted all-perovskite stacked cell.

[0138] Test Case

[0139] Initial performance test of all-perovskite tandem cells: At 25°C and AM 1.5G standard solar spectrum, a solar simulator was used to set the voltage range to 2V to -0.5V, and the current output of the all-perovskite tandem cells prepared in Examples 1-4 and Comparative Examples 1-2 at different voltages was tested, and the corresponding current-voltage (IV) characteristic curves were plotted, where the cell surface area was 1.1664cm 2 , the incident light power (Pin) is 100mW / cm 2 The characteristic curve at this time is the characteristic curve of initial performance, and the initial performance (initial open circuit voltage, initial short circuit current density, initial fill factor and initial photoelectric conversion efficiency) of the all-perovskite stacked cells prepared in Examples 1-4 and Comparative Examples 1-2 are obtained based on the characteristic curve of initial performance.

[0140] (1) Open circuit voltage (Voc): The voltage value corresponding to when the current is equal to zero.

[0141] (2) Short-circuit current density (Jsc): The current value when the voltage is zero is the short-circuit current (Isc), and the current per unit battery surface area is the short-circuit current density.

[0142] (3) Fill factor (FF): The ratio of the maximum output power (Pmax) of the battery to the product of the open circuit voltage and the short circuit current. The calculation formula is (Pmax / Voc*Isc), where the maximum power point is the point where the battery output power reaches its maximum value.

[0143] (4) Photoelectric conversion efficiency (PCE): Photoelectric conversion efficiency refers to the ratio of maximum output power to incident light power (Pin), and the calculation formula is (Pmax / Pin)*100%.

[0144] Aging performance test of all-perovskite stacked cells: The all-perovskite stacked cells prepared in Examples 1-4 and Comparative Examples 1-2 were aged for 100 h at 100°C and AM 1.5G open circuit. A solar simulator was used to set the voltage range to 2V to -0.5V. The current output of the all-perovskite stacked cells prepared in Examples 1-4 and Comparative Examples 1-2 at different voltages was tested, and the corresponding current-voltage (IV) characteristic curves were plotted. The cell surface area was 1.1664 cm 2 , the incident light power (Pin) is 100mW / cm 2 The characteristic curve at this time is the characteristic curve of aging performance, and the aging performance (open circuit voltage after aging, short circuit current density after aging, fill factor after aging, and photoelectric conversion efficiency after aging) of the all-perovskite stacked cells prepared in Examples 1-4 and Comparative Examples 1-2 is obtained from the characteristic curve of aging performance.

[0145] Efficiency ratio of all-perovskite tandem cells: Efficiency ratio = initial photoelectric conversion efficiency / photoelectric conversion efficiency after aging × 100%.

[0146] The test results of the initial performance, aging performance and efficiency ratio of the upright all-perovskite tandem solar cells prepared in Examples 1-2 and Comparative Example 1 are shown in Table 1; the test results of the initial performance, aging performance and efficiency ratio of the inverted all-perovskite tandem cells prepared in Examples 3-4 and Comparative Example 2 are shown in Table 2.

[0147] Table 1: Initial performance, aging performance and efficiency ratio of the upright all-perovskite tandem cells prepared in Examples 1-2 and Comparative Example 1

[0148]

[0149]

[0150] Table 2: Initial performance, aging performance and efficiency ratio of inverted all-perovskite tandem cells prepared in Examples 3-4 and Comparative Example 2

[0151]

[0152] It can be seen from Table 1 that, compared with the normal all-perovskite stack cell containing a tunneling layer prepared by the traditional evaporation method in Comparative Example 1, the initial performance, aging performance and efficiency ratio of the normal all-perovskite stack cell containing a tunneling layer prepared by the RPD method in Example 2 are all improved, which means that the device performance and stability of the normal all-perovskite stack cell containing the tunneling layer prepared by the RPD method are excellent; further, compared with the normal all-perovskite stack cell containing a tunneling layer prepared by the RPD method, the initial performance, aging performance and efficiency ratio of the normal all-perovskite stack cell in Example 1 that includes both a tunneling layer prepared by the RPD method and a buffer layer prepared by the RPD method between the metal electrode layer and the electron transport layer are all improved, which means that the buffer layer prepared by the RPD method between the metal electrode layer and the electron transport layer can further improve the device performance and stability of the normal all-perovskite stack cell.

[0153] It can be seen from Table 2 that, compared with the inverted all-perovskite tandem cell in Comparative Example 2 containing a tunneling layer prepared by the traditional sputtering method, the initial performance, aging performance and efficiency ratio of the inverted all-perovskite tandem cell in Example 4 containing a tunneling layer prepared by the RPD method are all improved, which means that the device performance and stability of the inverted all-perovskite tandem cell containing the tunneling layer prepared by the RPD method are excellent; further, compared with the inverted all-perovskite tandem cell containing a tunneling layer prepared by the RPD method, the initial performance, aging performance and efficiency ratio of the inverted all-perovskite tandem cell in Example 3 containing both a tunneling layer prepared by the RPD method and a transparent electrode layer deposited by the RPD method are all improved, which means that the transparent electrode layer deposited by the RPD method can further improve the device performance and stability of the inverted all-perovskite tandem cell.

Claims

1. A full perovskite tandem battery, characterized in that: The all-perovskite stacked cell includes a wide-bandgap perovskite top cell, a tunneling layer and a narrow-bandgap perovskite bottom cell in sequence from the light-entering surface. The tunneling layer is prepared by a reactive plasma deposition method, and the material of the tunneling layer is a transparent conductive metal oxide.

2. The all-perovskite tandem cell according to claim 1, characterized in that: The all-perovskite stacked cell has one or more of the following features: The transparent conductive metal oxide is selected from one or more of tungsten-doped indium oxide, indium zinc oxide, indium oxide, indium tin oxide, cerium-doped indium oxide, zirconium-doped indium oxide and gallium zinc-doped indium oxide; The thickness of the tunneling layer is 5-100 nm; The all-perovskite stacked cell includes an upright all-perovskite stacked cell and an inverted all-perovskite stacked cell.

3. The all-perovskite tandem cell according to claim 2, characterized in that: In the upright all-perovskite stacked cell, the wide-bandgap perovskite top cell includes, from the light incident side, a substrate, a transparent electrode layer, a hole transport layer, a wide-bandgap perovskite layer and an electron transport layer; the narrow-bandgap perovskite bottom cell includes, from the light incident side, a hole transport layer, a narrow-bandgap perovskite layer, an electron transport layer, a buffer layer A and a metal electrode layer; and / or In the inverted all-perovskite stacked cell, the wide-bandgap perovskite top cell includes, from the light-incident side, a transparent electrode layer, an electron transport layer, a wide-bandgap perovskite layer, and a hole transport layer; The narrow-bandgap perovskite bottom cell comprises, from the light-entering side, an electron transport layer, a narrow-bandgap perovskite layer, a hole transport layer, a transparent electrode layer and a substrate.

4. The all-perovskite tandem cell according to claim 3, characterized in that: The all-perovskite stacked cell has one or more of the following features: In the wide bandgap perovskite top cell, the bandgap width of the wide bandgap perovskite layer is 1.5-3.0 eV; In the wide bandgap perovskite top cell, the thickness of the wide bandgap perovskite layer is 200-2000nm; In the narrow bandgap perovskite bottom cell, the bandgap width of the narrow bandgap perovskite layer is 1.0-1.5 eV; In the narrow bandgap perovskite bottom-top cell, the thickness of the narrow bandgap perovskite layer is 400-3000nm; The chemical formula of the perovskite structure material is ABX3, A is a monovalent cation, including one or more of cesium, rubidium, methylamine and methylamidine; B is a divalent cation, including one or more of lead, copper, zinc, gallium, tin and calcium; X is a monovalent anion, including one or more of iodine, bromine, chlorine, fluorine, thiocyanate ion, tetrafluoroborate and hexafluorophosphate ion.

5. The all-perovskite tandem cell according to claim 3, characterized in that: In the upright all-perovskite stacked cell, the buffer layer A is prepared by reactive plasma deposition, and the material of the buffer layer A is a transparent conductive metal oxide; or In the upright all-perovskite stacked cell, the material of the buffer layer A is SnO2.

6. The all-perovskite tandem cell according to claim 5, characterized in that: The buffer layer A is prepared by reactive plasma deposition, and when the material of the buffer layer A is a transparent conductive metal oxide, the thickness of the buffer layer is 5-100 nm; When the material of the buffer layer A is SnO2, the thickness of the buffer layer is 5-100 nm.

7. The all-perovskite tandem cell according to claim 3, characterized in that: The wide bandgap perovskite top cell of the inverted all-perovskite stack cell includes a buffer layer B, the buffer layer B is located between the transparent electrode layer and the electron transport layer, and the material of the buffer layer B is SnO2.

8. A method for preparing a full perovskite tandem battery, characterized in that: The method comprises the following steps: (1) depositing a transparent electrode layer, a hole transport layer, a wide bandgap perovskite layer and an electron transport layer on the surface of a substrate in sequence to obtain a wide bandgap perovskite top cell; (2) using reactive plasma deposition to deposit a tunneling layer on the surface of the electron transport layer in the wide bandgap perovskite top cell; (3) depositing a hole transport layer, a narrow bandgap perovskite layer, an electron transport layer, a buffer layer A and a metal electrode layer on the surface of the tunneling layer in sequence to obtain a narrow bandgap perovskite bottom cell and an upright all-perovskite stacked cell; or (1') depositing a transparent electrode layer, a hole transport layer, a narrow bandgap perovskite layer and an electron transport layer on the surface of a substrate in sequence to obtain a narrow bandgap perovskite bottom cell; (2') depositing a tunneling layer on the surface of the electron transport layer in the narrow bandgap perovskite bottom cell by reactive plasma deposition; (3') depositing a hole transport layer, a wide bandgap perovskite layer, an electron transport layer and a transparent electrode layer on the surface of the tunneling layer in sequence, thereby obtaining a wide bandgap perovskite top cell and an inverted all-perovskite stacked cell.

9. The method according to claim 8, characterized in that Step (3') further comprises depositing a buffer layer B on the surface of the electron transport layer, and then depositing a transparent electrode layer.

10. The method according to claim 8 or 9, characterized in that The method has one or more of the following features: The wide bandgap perovskite layer is deposited by spin coating, blade coating, evaporation, printing, spray coating, spray pyrolysis or slit coating; The narrow bandgap perovskite layer is deposited by spin coating, blade coating, evaporation, printing, spray coating, spray pyrolysis or slit coating; The buffer layer A is deposited by reactive plasma deposition or atomic layer deposition; The buffer layer B is deposited by atomic layer deposition. The transparent electrode layer may be deposited by reactive plasma deposition, magnetron sputtering, electron beam evaporation or thermal evaporation.

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