Perovskite solar cell and preparation method and application thereof

Abstract

The invention relates to a perovskite solar cell and a preparation method and application thereof, in the perovskite solar cell, a buffer layer is arranged between an electron transport layer and a top electrode layer; the buffer layer comprises a tin oxide thin film doped with metal oxide, and the metal oxide comprises any one of aluminum oxide or indium oxide. The perovskite solar cell provided by the invention adopts the tin oxide doped with the specific metal oxide as the buffer layer, through doping of the metal oxide, the structure defect of the tin oxide thin film is reduced, the quality and performance of the buffer layer are improved, the buffer layer with excellent quality and performance is arranged between the electron transport layer and the top electrode layer, and the performance of the solar cell is improved. The morphology and the structure of the perovskite solar cell are stabilized, and the electrochemical performance of the perovskite solar cell is improved.

Description

Technical Field

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

[0002] Perovskite solar cells (PSCs) are emerging as innovators in photovoltaic (PV) technology. As a dark horse in the field of PV, cutting-edge PSCs using organic-inorganic halide perovskites (OIHPs) can achieve power conversion efficiencies (PCEs) exceeding 26%, comparable to single-crystalline silicon solar cells.

[0003] Perovskite solar cells generally suffer from poor stability. In particular, the materials in the electron transport layer tend to aggregate over time and develop structural defects such as dangling hydroxyl groups and oxygen vacancies, which deteriorate the morphology of the resulting electron transport layer and the optoelectronic performance of the cell.

[0004] In view of the above-mentioned defect sources, people currently mainly use additives and interface engineering methods to stabilize the electron transport layer, thereby stabilizing the perovskite solar cell. For example, CN118301957A discloses a composite electron transport layer and a preparation method thereof and a perovskite cell, wherein the composite electron transport layer includes an additive, wherein the additive includes polyhexamethylene guanidine hydrochloride and / or polyhexamethylene biguanidine hydrochloride, which can passivate the interface defects between the electron transport layer and the perovskite layer.

[0005] As an indispensable part of PSC devices, tin oxide (SnO 2 ) has received a lot of research and attention due to its excellent conductivity, high transmittance and chemical stability. High-quality SnO 2 Thin films can improve the stability of perovskite solar cells and can be obtained through a variety of preparation methods, such as colloidal spin coating, magnetron sputtering, chemical vapor deposition (CVD), reactive plasma deposition (RPD), pulsed laser deposition (PLD) and atomic layer deposition (ALD).

[0006] ALD technology is a method of thin film growth that achieves atomic-level control by sequentially injecting precursor pulses into the chamber. Compared with other thin film deposition technologies, this method has more outstanding advantages and can make flexible substrates and devices fully compatible. Therefore, ALD technology is gaining more and more attention.

[0007] In the application of ALD to prepare SnO 2 During the film deposition process, some structural defects will also be generated, which will lead to the reduction of the electrochemical performance of the film. 2Or chemical bath deposition method, it is difficult to add some additives to the tin source precursor to improve the structural defects generated during the film deposition process. This leads to the use of atomic layer deposition SnO 2 The performance of the film is poor, and it cannot effectively stabilize the structure of perovskite solar cells, and will affect the performance of PSCs prepared using it.

[0008] Therefore, providing a perovskite solar cell that has the advantages of both high stability and excellent electrochemical performance has become an urgent problem to be solved. Summary of the invention

[0009] In order to solve the above technical problems, the purpose of the present invention is to provide a perovskite solar cell and a preparation method and application thereof. The perovskite solar cell provided by the present invention uses tin oxide doped with a specific metal oxide as a buffer layer, and through the doping of the metal oxide, the structural defects of the tin oxide film are reduced, the quality and performance of the buffer layer are improved, and the buffer layer with excellent quality and performance is arranged between the electron transport layer and the top electrode layer, which stabilizes the morphology and structure of the perovskite solar cell and improves the electrochemical performance of the perovskite solar cell.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] In a first aspect, the present invention provides a perovskite solar cell, in which a buffer layer is provided between an electron transport layer and a top electrode layer;

[0012] The buffer layer includes a tin oxide film doped with a metal oxide, and the metal oxide includes any one of aluminum oxide and indium oxide.

[0013] In the buffer layer of the perovskite solar cell provided by the present invention, aluminum oxide or indium oxide is uniformly dispersed in the tin oxide film as a metal oxide, which has a doping effect, so that the conductivity of the film is improved, the energy level is more matched, the structural defects of the tin oxide film in the buffer layer can be reduced, and the quality and performance of the buffer layer can be improved. Furthermore, the tin oxide doped with a specific metal oxide is located between the electron transport layer and the top electrode layer of the perovskite solar cell as a buffer layer, which can improve the quality and performance of the electron transport layer, stabilize the morphology and structure of the perovskite solar cell, and improve the performance of the perovskite solar cell.

[0014] Preferably, based on the total mass of the buffer layer as 100wt%, the doping amount of the metal oxide in the buffer layer is 2-10wt%, for example, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt% or 10wt%, etc.

[0015] The present invention regulates the doping amount of metal oxide in the buffer layer to ensure the improvement of the conductivity of the film, better matching of the energy levels, optimize the structural defects of the tin oxide film in the buffer layer, improve the quality and performance of the buffer layer, thereby improving the stability of the perovskite solar cell structure and enhancing the electrochemical performance of the perovskite solar cell.

[0016] Preferably, the buffer layer has a thickness of 10-20 nm, for example, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm or 20 nm.

[0017] The present invention adjusts the thickness of the buffer layer within a reasonable range, aiming to improve the conductivity of the film, make the energy levels more matched, and reduce structural defects.

[0018] Preferably, the material of the electron transport layer includes C 60 、TiO 2 SnO 2 , ZnO or PC 61 Any one or a combination of at least two of BM.

[0019] In the present invention, the "PC 61 BM" refers to (6,6)-phenyl-C 61 -Methyl butyrate.

[0020] Preferably, the thickness of the electron transport layer is 10-30 nm, for example, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, 20 nm, 22 nm, 24 nm, 26 nm, 28 nm or 30 nm.

[0021] Preferably, the thickness of the top electrode layer is 140-160 nm, for example, 140 nm, 142 nm, 144 nm, 146 nm, 148 nm, 150 nm, 152 nm, 154 nm, 156 nm, 158 nm or 160 nm.

[0022] Preferably, the top electrode layer is a conductive cathode.

[0023] Preferably, the material of the top electrode layer includes any one of gold, silver, copper, platinum or carbon, or a combination of at least two of them.

[0024] Preferably, the perovskite solar cell comprises a substrate layer, a hole transport layer, a perovskite layer, the electron transport layer, the buffer layer and the top electrode layer which are stacked in sequence.

[0025] Preferably, the material of the perovskite layer includes a general formula of ABX 3A perovskite material, wherein A includes any one of cesium, rubidium, methylamino or methylamidine, or a combination of at least two thereof, B includes lead and / or tin, and X includes any one of bromine, iodine or chlorine, or a combination of at least two thereof.

[0026] Preferably, the thickness of the perovskite layer is 350-650 nm, for example, 350 nm, 400 nm, 500 nm, 550 nm, 600 nm or 650 nm.

[0027] Preferably, the material of the hole transport layer includes nickel oxide, cuprous oxide, 3-hexyl substituted polythiophene (P 3 HT), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA) or 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) or a combination of at least two thereof.

[0028] Preferably, the hole transport layer has a thickness of 10-200 nm, for example, 10 nm, 20 nm, 40 nm, 60 nm, 80 nm, 100 nm, 120 nm, 140 nm, 160 nm, 180 nm or 200 nm.

[0029] Preferably, the base layer comprises a substrate and a conductive anode.

[0030] Preferably, the substrate includes any one of glass, silicon wafer, polyethylene terephthalate substrate or polyimide substrate, or a combination of at least two of them.

[0031] Preferably, the conductive anode comprises any one of ITO, FTO or Ag nanowires, or a combination of at least two thereof.

[0032] Preferably, the thickness of the conductive anode is 50-1000 nm, for example, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm or 1000 nm.

[0033] Preferably, the total thickness of the base layer is 0.001-5 mm, for example, 0.001 mm, 0.01 mm, 0.05 mm, 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm, etc.

[0034] In a second aspect, the present invention provides a method for preparing a perovskite solar cell as described in the first aspect, the preparation method comprising:

[0035] A hole transport layer, a perovskite layer, an electron transport layer, a buffer layer and a top electrode layer are sequentially prepared on the substrate layer to obtain the perovskite solar cell;

[0036] The buffer layer includes a tin oxide film doped with a metal oxide, and the metal oxide includes any one of aluminum oxide and indium oxide.

[0037] In the preparation method of the perovskite solar cell provided by the present invention, a buffer layer composed of a tin oxide thin film doped with a metal oxide is prepared on the surface of the electron transport layer. On the one hand, aluminum oxide or indium oxide is used as a specific metal oxide to dope the tin oxide, which can reduce the structural defects generated in the preparation process of the tin oxide thin film, improve the conductivity of the film, make the energy level more matched, and improve the performance of the tin oxide thin film; on the other hand, the introduction of a buffer layer with excellent performance between the electron transport layer and the top electrode layer of the battery can improve the structural stability of the perovskite solar cell, thereby improving the electrochemical performance of the obtained perovskite solar cell.

[0038] Preferably, the buffer layer is prepared by atomic layer deposition.

[0039] The atomic layer deposition method used in the preparation of the buffer layer of the present invention controls the growth of the film at the atomic level, has large-area growth capability, precise control of layer thickness characteristics, good uniformity of film deposition, and excellent three-dimensional conformal characteristics, and its precise control can be combined with the design of a specific deposition process to uniformly dope the metal oxide in the tin oxide film, more effectively reduce the structural defects generated by the tin oxide film during the deposition process, improve the conductivity of the film, make the energy level more matched, improve the quality and performance of the buffer layer, and further improve the structural stability and electrochemical performance of the perovskite solar cell. In addition, the use of an atomic deposition method with large-area growth capability can achieve large-area preparation of the buffer layer, which is more suitable for industrial production.

[0040] Preferably, the buffer layer is prepared using an atomic layer deposition reactor.

[0041] Preferably, the atomic layer deposition reactor is evacuated before deposition until the background vacuum of the atomic layer deposition reactor is 1×10 -4 Torr or less, for example 1×10 -4 Torr, 8×10 -5 Torr, 6×10 -5 Torr, 4×10 - 5 Torr, 2×10 -5 Torr or 1×10 -5 Torr et al.

[0042] Preferably, the operating vacuum degree of the atomic layer deposition reactor is 0.1-0.2 Torr, for example, 0.1 Torr, 0.12 Torr, 0.14 Torr, 0.16 Torr, 0.18 Torr or 0.2 Torr.

[0043] Preferably, the deposition temperature during the preparation of the buffer layer is 80-120°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C or 120°C.

[0044] Preferably, the specific preparation method of the buffer layer includes the following steps:

[0045] S1. Depositing a tin source and a first oxygen source sequentially on the surface of the electron transport layer away from the perovskite layer, and passing a gas for purging after each deposition, and repeating the cycle 15-25 times;

[0046] S2. Continue to sequentially deposit the doped metal source and the second oxygen source on the component obtained in step S1, and introduce gas for purging after each deposition;

[0047] S3. Repeat step S1 and step S2 for 4-8 times in sequence to obtain the buffer layer.

[0048] The present invention designs a special alternating deposition process using a tin source, a first oxygen source, a doped metal source and a second oxygen source as raw materials, which can promote and optimize the doping effect of doped metal oxides in tin oxide, reduce structural defects generated during the preparation process of the metal oxide-doped tin oxide film, improve the conductivity of the film, make the energy levels more matched, and improve the performance of the tin oxide film.

[0049] Preferably, the gas introduced for the purge in step S1 and the purge in step S2 is independently selected from nitrogen and / or an inert gas.

[0050] Preferably, the inert gas includes any one of argon, helium or neon.

[0051] Preferably, the tin source in step S1 includes tetrakis(dimethylamino)tin.

[0052] The chemical formula of "tetrakis(dimethylamino)tin" in the present invention is Sn(C 2 H 6 N) 4 , which uses tetravalent tin.

[0053] Preferably, in step S1, the first oxygen source comprises H 2 O.

[0054] Preferably, in a single cycle of step S1, the deposition time of the tin source is 0.05-0.2 s, such as 0.05 s, 0.1 s, 0.15 s or 0.2 s.

[0055] Preferably, in a single cycle of step S1, the purging time after depositing the tin source is 5-15 s, for example, 5 s, 6 s, 7 s, 8 s, 9 s, 10 s, 11 s, 12 s, 13 s, 14 s or 15 s.

[0056] Preferably, in a single cycle of step S1, the deposition time of the first oxygen source is 0.1-1 s, for example, 0.1 s, 0.2 s, 0.3 s, 0.4 s, 0.5 s, 0.6 s, 0.7 s, 0.8 s, 0.9 s or 1 s.

[0057] Preferably, in a single cycle of step S1, the purging time after depositing the first oxygen source is 5-15 s, for example, 5 s, 6 s, 7 s, 8 s, 9 s, 10 s, 11 s, 12 s, 13 s, 14 s or 15 s.

[0058] Preferably, the doping metal source in step S2 includes any one of an aluminum source and an indium source, or a combination of at least two of them.

[0059] Preferably, the aluminum source comprises trimethylaluminum.

[0060] Preferably, the indium source comprises trimethylindium.

[0061] Preferably, in step S2, the second oxygen source comprises H 2 O.

[0062] Preferably, in step S2, the deposition time of the doping metal source is 0.05-0.2 s, such as 0.05 s, 0.1 s, 0.15 s or 0.2 s.

[0063] Preferably, in step S2, the purging time after depositing the doping metal source is 15-25 s, for example, 15 s, 16 s, 17 s, 18 s, 19 s, 20 s, 21 s, 22 s, 23 s, 24 s or 25 s, etc.

[0064] Preferably, in step S2, the deposition time of the second oxygen source is 0.1-0.5 s, such as 0.1 s, 0.2 s, 0.3 s, 0.4 s or 0.5 s.

[0065] Preferably, in step S2, the purging time after depositing the second oxygen source is 15-25 s, for example, 15 s, 16 s, 17 s, 18 s, 19 s, 20 s, 21 s, 22 s, 23 s, 24 s or 25 s.

[0066] In the preparation process of the buffer layer provided by the present invention, by regulating the deposition time of the raw materials, the doping amount of the metal oxide in the buffer layer and the doping uniformity of the metal oxide in the buffer layer are further regulated, thereby more effectively reducing the structural defects of the tin oxide film during the deposition process, improving the conductivity of the film, making the energy levels more matched, and further improving the quality and performance of the buffer layer.

[0067] Preferably, the preparation methods of the hole transport layer and the electron transport layer are independently selected from any one of thermal evaporation, solution spin coating, slit coating, inkjet printing, vacuum thermal deposition, electron beam evaporation, magnetron sputtering or atomic layer deposition.

[0068] Preferably, the method for preparing the perovskite layer comprises: dissolving the raw materials for preparing the perovskite layer in an organic solvent according to the composition of the perovskite layer to obtain a precursor solution, and coating the precursor solution on the surface of the hole transport layer away from the substrate layer to obtain the perovskite layer.

[0069] Preferably, the raw materials for preparing the perovskite layer include a first precursor material and a second precursor material.

[0070] Preferably, the first precursor material includes any one of cesium halide, rubidium halide, cesium carbonate, rubidium carbonate, formamidine hydrohalide or methylamine halide, or a combination of at least two thereof.

[0071] Preferably, the second precursor material comprises lead halide and / or tin halide.

[0072] Preferably, the specific preparation method of the perovskite layer includes: dissolving the first precursor material and the second precursor material in an organic solvent to obtain a precursor solution, and coating the precursor solution on the surface of the hole transport layer away from the substrate layer to obtain the perovskite layer.

[0073] Preferably, in preparing the perovskite layer, the organic solvent includes N,N-dimethylformamide and dimethyl sulfoxide.

[0074] Preferably, in the preparation of the perovskite layer, in the organic solvent, the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is (7-9):(1-3), such as 7:3, 8:2 or 9:1.

[0075] Preferably, in the preparation of the perovskite layer, the concentration of the precursor solution is 0.5-2 mol / L, for example, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L, 1 mol / L, 1.2 mol / L, 1.4 mol / L or 1.5 mol / L, etc.

[0076] Preferably, in the preparation of the perovskite layer, the coating method includes any one of a solution spin coating method, a slit coating method or an inkjet printing method.

[0077] Preferably, the method for preparing the top electrode layer comprises: evaporating a conductive cathode on the surface of the buffer layer on a side away from the electron transport layer to obtain the top electrode layer.

[0078] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0079] (1) forming a base layer using a substrate material and a conductive anode material, and washing the base layer to obtain the pretreated base layer;

[0080] (2) preparing a hole transport layer on the pretreated substrate layer, wherein the preparation method of the hole transport layer includes any one of thermal evaporation, spin coating, slit coating, inkjet printing, vacuum thermal deposition, electron beam evaporation, magnetron sputtering or atomic layer deposition;

[0081] (3) The first precursor material and the second precursor material are prepared according to the elements contained in the material to satisfy the molecular formula ABX 3 The first precursor material and the second precursor material are dissolved in an organic solvent, wherein the organic solvent is composed of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of (7-9):(1-3), to obtain a precursor solution with a concentration of 0.5-2 mol / L;

[0082] Coating the precursor solution on the surface of the hole transport layer away from the substrate layer by any one of solution spin coating, slit coating or inkjet printing to obtain the perovskite layer;

[0083] (4) preparing an electron transport layer on the surface of the perovskite layer away from the hole transport layer, wherein the preparation method of the electron transport layer includes any one of thermal evaporation, solution spin coating, slit coating, inkjet printing, vacuum thermal deposition, electron beam evaporation, magnetron sputtering or atomic layer deposition;

[0084] (5) placing the component obtained in step (4) in an atomic layer deposition reactor, and evacuating the atomic layer deposition reactor until the background vacuum of the instrument is 1×10 -4Torr or less, setting the working vacuum degree of the atomic layer deposition reactor to 0.1-0.2 Torr and the deposition temperature to 80-120°C during the deposition process; performing a deposition process on the surface of the electron transport layer away from the perovskite layer, specifically: sequentially performing 0.05-0.2s of tin source deposition, then nitrogen and / or inert gas purging for 5-15s, then performing 0.1-1s of first oxygen source deposition, then nitrogen and / or inert gas purging for 5-15s, and repeating the cycle 15-25 times; then, continuing to sequentially perform 0.05-0.2s of doped metal source deposition, then nitrogen and / or inert gas purging for 15-25s, then performing 0.1-0.5s of second oxygen source deposition, then nitrogen and / or inert gas purging for 15-25s; the doped metal source includes any one of an aluminum source or an indium source; the first oxygen source includes H 2 O; the second oxygen source includes H 2 O;

[0085] (6) Repeating the deposition process in step (5) 4-8 times to obtain the buffer layer;

[0086] (7) Vapor-depositing a conductive cathode on the surface of the buffer layer away from the electron transport layer to obtain the top electrode layer, and finally preparing the perovskite solar cell.

[0087] In a third aspect, the present invention provides a perovskite solar module, wherein the perovskite solar module comprises the perovskite solar cell described in the first aspect.

[0088] The perovskite solar cell module provided in the present invention is composed of a plurality of perovskite solar cells connected in series.

[0089] Compared with the prior art, the present invention has at least the following beneficial effects:

[0090] (1) In the buffer layer of the perovskite solar cell provided by the present invention, aluminum oxide or indium oxide is uniformly dispersed in the tin oxide film as a metal oxide, which has a doping effect, so that the conductivity of the film is improved, the energy level is more matched, and the structural defects of the tin oxide film in the buffer layer can be reduced, and the quality and performance of the buffer layer can be improved. Furthermore, the tin oxide doped with a specific metal oxide is located as a buffer layer between the electron transport layer and the top electrode layer of the perovskite solar cell, which can improve the quality and performance of the electron transport layer, stabilize the morphology and structure of the perovskite solar cell, and improve the electrochemical performance of the perovskite solar cell.

[0091] (2) In the preparation method of the perovskite solar cell provided by the present invention, a buffer layer composed of a tin oxide thin film doped with a metal oxide is prepared on the surface of the electron transport layer. On the one hand, aluminum oxide or indium oxide is used as a specific metal oxide to dope the tin oxide, which can reduce the structural defects generated during the preparation of the tin oxide thin film, improve the conductivity of the film, make the energy level more matched, and improve the performance of the tin oxide thin film; on the other hand, the introduction of a buffer layer with excellent performance between the electron transport layer and the top electrode layer of the battery can improve the structural stability of the perovskite solar cell, thereby improving the electrochemical performance of the resulting perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0092] Figure 1 It is a schematic structural diagram of the perovskite solar cell provided by the present invention.

[0093] Figure 2 It is a schematic diagram of the structure of the buffer layer in the perovskite solar cell provided in Example 1 of the present invention.

[0094] Among them, 1, base layer; 2, hole transport layer; 3, perovskite layer; 4, electron transport layer; 5, buffer layer; 51, tin oxide; 52, aluminum oxide; 6, top electrode layer. DETAILED DESCRIPTION

[0095] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementation methods. However, the following examples are only simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0096] Example 1

[0097] This embodiment provides a perovskite solar cell, and its structural schematic diagram is as follows Figure 1 As shown, it includes a substrate layer 1, a hole transport layer 2, a perovskite layer 3, an electron transport layer 4, a buffer layer 5 and a top electrode layer 6 stacked in sequence from bottom to top; the substrate layer 1 is a FTO glass substrate, the thickness of the conductive anode FTO is 700nm, and the total thickness of the substrate layer 1 is 3mm; the material of the hole transport layer 2 is nickel oxide, and its thickness is 15nm; the material of the perovskite layer 3 is Cs 0.05 MA 0.076 FA 0.874 Pb(I 0.92 Br 0.08 ) 3 , its thickness is 400nm; the material of the electron transport layer 4 is C 60 , with a thickness of 20 nm; the material of the buffer layer 5 is tin oxide 51 doped with aluminum oxide 52, and its structural schematic diagram is shown as Figure 2As shown, based on the total mass of the buffer layer 5 being 100wt%, the doping amount of the aluminum oxide 52 is 5wt% and its thickness is 15nm; the top electrode layer 6 is made of metal copper as a conductive cathode and its thickness is 150nm.

[0098] This embodiment also provides a method for preparing a perovskite solar cell, the method comprising the following steps:

[0099] (1) Using glass as a substrate material and FTO conductive anode to form a substrate layer 1, the FTO conductive anode is located on the surface of the glass substrate material, and using deionized water, acetone and isopropanol to ultrasonically wash the substrate layer 1 for 15 minutes in sequence to obtain a pretreated substrate layer 1.

[0100] (2) Using a thermal evaporation method, nickel oxide with a thickness of 15 nm is deposited on the surface of the FTO conductive anode in the pretreated base layer 1 obtained in step (1) to obtain a hole transport layer 2.

[0101] (3) In a nitrogen-filled glove box, cesium iodide, formamidine hydroiodide, methylammonium iodide, lead iodide and lead bromide were prepared according to the obtained Cs 0.05 MA 0.076 FA 0.874 Pb(I 0.92 Br 0.08 ) 3 The molar amount of the element in the step (2) is weighed and dissolved in an organic solvent consisting of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 7:3 to obtain a precursor solution with a concentration of 1 mol / L. The obtained precursor solution is coated on the surface of the hole transport layer 2 obtained in step (2) away from the substrate layer 1 by a slit coating method to obtain a 400 nm thick layer with a composition of Cs 0.05 MA 0.076 FA 0.874 Pb(I 0.92 Br 0.08 ) 3 of the perovskite layer3.

[0102] (4) On the surface of the perovskite layer 3 obtained in step (3) away from the hole transport layer 2, a C layer with a thickness of 20 nm is deposited by thermal evaporation. 60 , and obtain the electron transport layer 4.

[0103] (5) The component obtained in step (4) is placed in an atomic layer deposition reactor and evacuated until the background vacuum in the reactor is 1×10 -4Torr, the working vacuum of the instrument during the deposition process was set to 0.15 Torr, and the deposition temperature was 100°C; the deposition process was performed on the surface of the electron transport layer 4 away from the perovskite layer 3, specifically: 0.1s of tetrakis(dimethylamino)tin(IV) deposition, then argon purge for 10s, and then 0.5s of H 2 O deposition, followed by argon purge for 10 s, repeated 20 times; then, trimethylaluminum deposition for 0.1 s, argon purge for 20 s, and H 2 O deposition, and then argon purge for 20 s.

[0104] (6) Repeat the deposition process in step (5) for 5 times to obtain a buffer layer 5 of aluminum oxide 52 doped with tin oxide 51 with a thickness of 15 nm.

[0105] (7) A metal copper layer is evaporated on the surface of the buffer layer 5 obtained in step (6) away from the electron transport layer 4 to obtain a copper conductive cathode with a thickness of 150 nm as the top electrode layer 6, and finally a perovskite solar cell is prepared.

[0106] Example 2

[0107] This embodiment provides a perovskite solar cell, and its structural schematic diagram is as follows Figure 1 As shown, it includes a substrate layer 1, a hole transport layer 2, a perovskite layer 3, an electron transport layer 4, a buffer layer 5 and a top electrode layer 6 stacked in sequence from bottom to top; the substrate layer 1 is a FTO glass substrate, the thickness of the conductive anode FTO is 700nm, and the total thickness of the substrate layer 1 is 3mm; the material of the hole transport layer 2 is nickel oxide, and its thickness is 15nm; the material of the perovskite layer 3 is Cs 0.05 MA 0.076 FA 0.874 Pb(I 0.92 Br 0.08 ) 3 , its thickness is 450nm; the material of the electron transport layer 4 is C 60 , its thickness is 30nm; the material of the buffer layer 5 is tin oxide doped with indium oxide. Based on the total mass of the buffer layer 5 being 100wt%, the doping amount of indium oxide is 4wt%, and its thickness is 20nm; the top electrode layer 6 is made of metal gold as a conductive cathode, and its thickness is 160nm.

[0108] This embodiment also provides a method for preparing a perovskite solar cell, the method comprising the following steps:

[0109] (1) Using glass as a substrate material and FTO conductive anode to form a substrate layer 1, the FTO conductive anode is located on the surface of the glass substrate material, and using deionized water, acetone and isopropanol to ultrasonically wash the substrate layer 1 for 10 minutes in sequence to obtain a pretreated substrate layer 1.

[0110] (2) Using a vacuum thermal deposition method, nickel oxide with a thickness of 15 nm is deposited on the surface of the FTO conductive anode in the pretreated substrate layer 1 obtained in step (1) to obtain a hole transport layer 2.

[0111] (3) In a nitrogen-filled glove box, cesium iodide, formamidine hydroiodide, methylammonium iodide, lead iodide and lead bromide were prepared according to the obtained Cs 0.05 MA 0.076 FA 0.874 Pb(I 0.92 Br 0.08 ) 3 The molar amount of the element in the step (2) is weighed and dissolved in an organic solvent consisting of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio of 8:2 to obtain a precursor solution with a concentration of 1.5 mol / L. The obtained precursor solution is coated on the surface of the hole transport layer 2 obtained in step (2) away from the substrate layer 1 by a solution spin coating method to obtain a 450 nm thick layer with a composition of Cs 0.05 MA 0.076 FA 0.874 Pb(I 0.92 Br 0.08 ) 3 of the perovskite layer3.

[0112] (4) A C layer with a thickness of 30 nm was prepared on the surface of the perovskite layer 3 obtained in step (3) away from the hole transport layer 2 by solution spin coating. 60 , and obtain the electron transport layer 4.

[0113] (5) The component obtained in step (4) is placed in an atomic layer deposition reactor and evacuated until the background vacuum in the reactor is 1×10 -5 Torr, the working vacuum degree of the instrument during the deposition process was set to 0.2 Torr, the deposition temperature was set to 120°C, and the deposition process was performed on the surface of the electron transport layer 4 away from the perovskite layer 3, specifically: 0.2s of tetrakis(dimethylamino)tin(IV) deposition, then nitrogen purge for 15s, and then 0.8s of H 2 O deposition, followed by nitrogen purge for 15 s, repeated 18 times; then, trimethylindium deposition for 0.2 s, nitrogen purge for 25 s, and H 2 O deposition, and then nitrogen purge for 25 s.

[0114] (6) Repeat the deposition process in step (5) for 6 times to obtain a buffer layer 5 of indium oxide doped with tin oxide with a thickness of 20 nm.

[0115] (7) A metal gold layer is evaporated on the surface of the buffer layer 5 obtained in step (6) away from the electron transport layer 4 to obtain a gold conductive cathode with a thickness of 160 nm as the top electrode layer 6, and finally a perovskite solar cell is prepared.

[0116] Example 3

[0117] The difference between this embodiment and embodiment 1 is that in the perovskite solar cell provided in this embodiment, the doping amount of the aluminum oxide 52 doped with the tin oxide 51 in the buffer layer 5 is 1wt%, based on the total mass of the buffer layer 5 being 100wt%. Accordingly, in the preparation method of the perovskite solar cell provided in this embodiment, the deposition time of trimethylaluminum in the deposition process of step (5) is 0.01s, followed by argon purge for 20s, followed by H 2 O deposition, and then argon purge for 20s. The rest of the contents are the same as in Example 1.

[0118] Example 4

[0119] The difference between this embodiment and embodiment 1 is that in the perovskite solar cell provided in this embodiment, the doping amount of the aluminum oxide 52 doped with the tin oxide 51 in the buffer layer 5 is 12wt%, based on the total mass of the buffer layer 5 being 100wt%. Accordingly, in the preparation method of the perovskite solar cell provided in this embodiment, the deposition time of trimethylaluminum in the deposition process of step (5) is 0.4s, followed by argon purge for 20s, followed by H 2 O deposition, and then argon purge for 20s. The rest of the contents are the same as in Example 1.

[0120] Example 5

[0121] The difference between this embodiment and embodiment 1 is that in the perovskite solar cell provided in this embodiment, the thickness of the buffer layer 5 is 5 nm. Accordingly, in the method for preparing a perovskite solar cell provided in this embodiment, step (6) repeats the deposition process of step (5) three times. The rest of the contents are the same as those in embodiment 1.

[0122] Example 6

[0123] The difference between this embodiment and embodiment 1 is that in the perovskite solar cell provided in this embodiment, the thickness of the buffer layer 5 is 30 nm. Accordingly, in the method for preparing a perovskite solar cell provided in this embodiment, step (6) repeats the deposition process of step (5) 10 times. The rest of the contents are the same as those in embodiment 1.

[0124] Example 7

[0125] The difference between this embodiment and embodiment 1 is that in the method for preparing a perovskite solar cell provided in this embodiment, the atomic layer deposition method used in step (5) is replaced by a magnetron sputtering method, that is, the specific process is as follows: the component obtained in step (4) is placed in a magnetron sputtering device, and the vacuum is evacuated to a background vacuum degree of 8×10 -5 Pa, the chamber pressure during sputtering is 0.2Pa, high-purity argon (99.999wt%) is used as the working gas, oxygen is used as the reaction gas, and the sputtering of the Sn sputtering target and the Al sputtering target is performed alternately, and each 100s of Sn sputtering is followed by 5s of Al sputtering, which is repeated 4 times to obtain a buffer layer 5 with a total mass of 100wt% and a doping amount of 5wt% of aluminum oxide 52 doped with tin oxide 51, and a thickness of 15nm. The rest of the contents are the same as those in Example 1.

[0126] Comparative Example 1

[0127] The difference between this comparative example and Example 1 is that in the perovskite solar cell provided in this comparative example, the doping of the metal oxide aluminum oxide 52 of the buffer layer 5 is omitted, and only the tin oxide 51 is used as the buffer layer 5. Accordingly, in the preparation method of the perovskite solar cell provided in this comparative example, the steps of sequentially performing 0.1 s of trimethylaluminum deposition, purging with argon for 20 s, and then performing 0.2 s of H 2 O deposition, and then argon purge for 20s. The rest of the contents are the same as in Example 1.

[0128] Comparative Example 2

[0129] The difference between this comparative example and Example 1 is that in the perovskite solar cell provided in this comparative example, the buffer layer 5 is omitted. Accordingly, in the preparation method of the perovskite solar cell provided in this comparative example, the preparation process of step (5) and step (6) is omitted, and the top electrode layer 6 is directly prepared on the surface of the electron transport layer 4. The rest of the contents are the same as in Example 1.

[0130] Comparative Example 3

[0131] The difference between this comparative example and Example 1 is that in the perovskite solar cell provided in this comparative example, the buffer layer 5 is composed of magnesium oxide doped with tin oxide 51, the doping amount of which is 5wt%, and the thickness of which is 15nm. Accordingly, in the preparation method of the perovskite solar cell provided in this example, step (5) replaces trimethylaluminum with bis(ethylcyclopentadienyl)magnesium, that is, bis(ethylcyclopentadienyl)magnesium is deposited for 0.08s, then purged with argon for 20s, and then H 2 O deposition, and then argon purge for 20s. The rest of the contents are the same as in Example 1.

[0132] The perovskite solar cells obtained from Examples 1-7 and Comparative Examples 1-3 were subjected to performance tests, and the testing method specifically includes the following contents:

[0133] At a temperature of 25° C. and nitrogen storage conditions, a Keithley 2400 source meter was used at AM 1.5G to perform performance tests on the perovskite solar cells obtained in Examples 1-7 and Comparative Examples 1-3. The test results are shown in Table 1.

[0134] Table 1

[0135]

[0136] The test results show that:

[0137] (1) It can be seen from Examples 1 to 2 that the present invention uses tin oxide doped with a specific metal oxide as a buffer layer. By doping with metal oxides, the structural defects of the tin oxide film are reduced and the quality and performance of the buffer layer are improved. Furthermore, the buffer layer with excellent quality and performance is arranged between the electron transport layer and the top electrode layer, which can stabilize the morphology and structure of the perovskite solar cell and improve the electrochemical performance of the perovskite solar cell.

[0138] (2) By comparing Example 1 with Examples 3-4, it can be seen that if the doping amount of metal oxide in the buffer layer of the present invention is too low, the doping effect is poor, resulting in no obvious improvement in component efficiency; if the doping amount of metal oxide is too high, the properties of the film itself will change, resulting in a decrease in the performance of the film, thereby affecting the efficiency of the titanium ore solar cell.

[0139] (3) By comparing Example 1 with Examples 5-6, it can be seen that in the present invention, if the thickness of the buffer layer is too thin, the protection effect is poor and it cannot withstand the damage during copper plating, resulting in low efficiency of the titanium ore solar cell; if the thickness of the buffer layer is too thick, the conductivity of the film will deteriorate, thereby affecting the performance of the titanium ore solar cell.

[0140] (4) By comparing Example 1 with Example 7, it can be seen that if the atomic layer deposition method used in the buffer layer preparation process of the present invention is replaced by a magnetron sputtering method, the underlying functional layer will be destroyed during the sputtering process, resulting in a very low efficiency of the titanium ore solar cell.

[0141] (5) By comparing Example 1 with Comparative Example 1, it can be seen that the present invention can reduce the structural defects of the tin oxide film in the buffer layer and improve the quality and performance of the buffer layer by doping metal oxide into the tin oxide film in the buffer layer. When metal oxide is not used for doping, the electrochemical performance of the perovskite solar cell will be reduced and the photoelectric conversion efficiency will be reduced.

[0142] (6) By comparing Example 1 with Comparative Example 2, it can be seen that the present invention can effectively protect and improve the quality and performance of the electron transport layer, stabilize the morphology and structure of the perovskite solar cell, and improve the electrochemical performance of the perovskite solar cell by providing a buffer layer between the electron transport layer and the top electrode layer. When the buffer layer is missing, it will lead to the inability to resist damage during copper plating, resulting in low efficiency of the perovskite solar cell.

[0143] (7) By comparing Example 1 with Comparative Example 3, it can be seen that if magnesium oxide is used to dope tin oxide in the present invention, the properties of the film will change, affecting the efficiency of the titanium ore solar cell.

[0144] In summary, in the buffer layer of the perovskite solar cell provided by the present invention, aluminum oxide or indium oxide is uniformly dispersed in the tin oxide film as a metal oxide, which has a doping effect, so that the conductivity of the film is improved, the energy level is more matched, and the structural defects of the tin oxide film in the buffer layer can be reduced, and the quality and performance of the buffer layer can be improved. Furthermore, tin oxide doped with a specific metal oxide is located between the electron transport layer and the top electrode layer of the perovskite solar cell as a buffer layer, which can improve the quality and performance of the electron transport layer, stabilize the morphology and structure of the perovskite solar cell, and improve the electrochemical performance of the perovskite solar cell.

[0145] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A perovskite solar cell, characterized in that: In the perovskite solar cell, a buffer layer is provided between the electron transport layer and the top electrode layer; The buffer layer includes a tin oxide film doped with a metal oxide, and the metal oxide includes any one of aluminum oxide and indium oxide.

2. The perovskite solar cell according to claim 1, characterized in that Based on the total mass of the buffer layer being 100wt%, the doping amount of the metal oxide in the buffer layer is 2-10wt%; Preferably, the thickness of the buffer layer is 10-20 nm; Preferably, the material of the electron transport layer includes C 60 , TiO2, SnO2, ZnO or PC 61 Any one or a combination of at least two of BM; Preferably, the thickness of the electron transport layer is 10-30 nm; Preferably, the thickness of the top electrode layer is 140-160 nm; Preferably, the top electrode layer is a conductive cathode; Preferably, the material of the top electrode layer includes any one of gold, silver, copper, platinum or carbon, or a combination of at least two of them.

3. The perovskite solar cell according to claim 1 or 2, characterized in that: The perovskite solar cell comprises a substrate layer, a hole transport layer, a perovskite layer, the electron transport layer, the buffer layer and the top electrode layer which are stacked in sequence; Preferably, the material of the perovskite layer includes a perovskite material of the general formula ABX3, wherein A includes any one of cesium, rubidium, methylamino or methylamidine or a combination of at least two thereof, B includes lead and / or tin, and X includes any one of bromine, iodine or chlorine or a combination of at least two thereof; Preferably, the thickness of the perovskite layer is 350-650 nm.

4. The perovskite solar cell according to claim 3, characterized in that: The material of the hole transport layer includes any one of nickel oxide, cuprous oxide, 3-hexyl substituted polythiophene, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] or 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene or a combination of at least two thereof; Preferably, the thickness of the hole transport layer is 10-200 nm; Preferably, the base layer comprises a substrate and a conductive anode; Preferably, the substrate comprises any one of glass, silicon wafer, polyethylene terephthalate substrate or polyimide substrate, or a combination of at least two thereof; Preferably, the conductive anode comprises any one of ITO, FTO or Ag nanowires or a combination of at least two thereof; Preferably, the total thickness of the base layer is 0.001-5 mm.

5. A method for preparing a perovskite solar cell according to any one of claims 1 to 4, characterized in that: The preparation method comprises: A hole transport layer, a perovskite layer, an electron transport layer, a buffer layer and a top electrode layer are sequentially prepared on the substrate layer to obtain the perovskite solar cell; The buffer layer includes a tin oxide film doped with a metal oxide, and the metal oxide includes any one of aluminum oxide and indium oxide.

6. The preparation method according to claim 5, characterized in that: The preparation method of the buffer layer includes atomic layer deposition; Preferably, the buffer layer is prepared using an atomic layer deposition reactor; Preferably, the atomic layer deposition reactor is evacuated before deposition until the background vacuum of the atomic layer deposition reactor is 1×10 -4 Torr or less; Preferably, the working vacuum degree of the atomic layer deposition reactor is 0.1-0.2 Torr; Preferably, the deposition temperature during the preparation of the buffer layer is 80-120°C.

7. The preparation method according to claim 5 or 6, characterized in that: The specific preparation method of the buffer layer includes the following steps: S1. Depositing a tin source and a first oxygen source sequentially on the surface of the electron transport layer away from the perovskite layer, and passing a gas for purging after each deposition, and repeating the cycle 15-25 times; S2. Continue to sequentially deposit the doped metal source and the second oxygen source on the component obtained in step S1, and introduce gas for purging after each deposition; S3. Repeat the cycle 4-8 times in the order of step S1 and step S2 to obtain the buffer layer; Preferably, the gas introduced in the purging in step S1 and the purging in step S2 is independently selected from nitrogen and / or an inert gas; Preferably, the inert gas includes any one of argon, helium or neon.

8. The preparation method according to claim 7, characterized in that: The tin source in step S1 includes tetrakis(dimethylamino)tin; Preferably, in step S1, the first oxygen source comprises H2O; Preferably, in a single cycle of step S1, the deposition time of the tin source is 0.05-0.2 s; Preferably, in a single cycle of step S1, the purging time after depositing the tin source is 5-15 seconds; Preferably, in a single cycle of step S1, the deposition time of the first oxygen source is 0.1-1s; Preferably, in a single cycle of step S1, the purge time after depositing the first oxygen source is 5-15 seconds; Preferably, the doping metal source in step S2 includes any one of an aluminum source or an indium source; Preferably, in step S2, the second oxygen source comprises H2O; Preferably, in step S2, the deposition time of the doping metal source is 0.05-0.2s; Preferably, in step S2, the purging time after depositing the doping metal source is 15-25 seconds; Preferably, in step S2, the deposition time of the second oxygen source is 0.1-0.5 s; Preferably, in step S2, the purging time after depositing the second oxygen source is 15-25 seconds.

9. The preparation method according to any one of claims 5 to 8, characterized in that: The preparation methods of the hole transport layer and the electron transport layer are independently selected from any one of thermal evaporation, solution spin coating, slit coating, inkjet printing, vacuum thermal deposition, electron beam evaporation, magnetron sputtering or atomic layer deposition; Preferably, the method for preparing the perovskite layer comprises: dissolving a raw material for preparing the perovskite layer in an organic solvent according to the composition of the perovskite layer to obtain a precursor solution, and coating the precursor solution on a surface of the hole transport layer away from the substrate layer to obtain the perovskite layer; Preferably, in preparing the perovskite layer, the concentration of the precursor solution is 0.5-2 mol / L; Preferably, in preparing the perovskite layer, the coating method includes any one of a solution spin coating method, a slit coating method or an inkjet printing method; Preferably, the method for preparing the top electrode layer comprises: evaporating a conductive cathode on the surface of the buffer layer on a side away from the electron transport layer to obtain the top electrode layer.

10. A perovskite solar cell module, characterized in that: The perovskite solar cell module comprises the perovskite solar cell according to any one of claims 1 to 4.

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