Perovskite thin film, preparation method thereof and photovoltaic device

Abstract

The invention belongs to the photovoltaic field, and particularly relates to a perovskite thin film, a preparation method thereof and a photovoltaic device. The preparation method of the perovskite thin film comprises the following steps: (1) mixing a perovskite structure substance raw material and a solvent to obtain a perovskite precursor solution; mixing inorganic nanoparticles with an anti-solvent to obtain an anti-solution; (2) spin-coating a perovskite precursor solution and then spin-coating a reverse solution to obtain a perovskite wet film; and (3) annealing the perovskite wet film to obtain a perovskite thin film which contains a perovskite structure substance. According to the preparation method, the uniformity and the crystallization quality of the perovskite thin film can be improved, and then the photoelectric property of a perovskite device is improved.

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaics, and in particular relates to a perovskite film, a preparation method thereof and a photovoltaic device. Background Art

[0002] Perovskite crystals have shown strong competitiveness due to their excellent photoelectric properties and easy solution preparation. Since being reported, the photoelectric conversion efficiency of metal halide perovskite solar cells has increased rapidly. In perovskite devices, perovskite film as a light-absorbing layer will directly affect the efficiency and stability of perovskite devices.

[0003] At present, it is difficult to control the uniform growth of perovskite films prepared by the solution method during the crystallization process, and the uneven growth rate will lead to certain differences in grain size and film thickness. The uneven perovskite film has a certain negative impact on the performance of devices prepared on a flat substrate and the performance of devices prepared on a rough velvet substrate. In addition, when preparing perovskite films on rough substrates, the uneven crystallization rate will lead to excessive stress on the bottom surface, which is prone to peeling off the perovskite film from the bottom interface or forming holes, which will further seriously affect the performance and stability of photovoltaic devices.

[0004] Therefore, there is an urgent need to develop a method for preparing perovskite films that can improve the uniformity and crystallization quality of perovskite films, thereby improving the photoelectric performance and stability of photovoltaic devices. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a method for preparing a perovskite film, which uses a reverse solution containing inorganic nanoparticles to prepare the perovskite film, thereby improving the uniformity and crystallization quality of the perovskite film, and further improving the photoelectric performance and stability of the photovoltaic device.

[0006] Specifically, the present invention provides a method for preparing a perovskite film, the method comprising the following steps:

[0007] (1) mixing a raw material of a perovskite structure material and a solvent to obtain a perovskite precursor solution; mixing inorganic nanoparticles and an anti-solvent to obtain an anti-solution;

[0008] (2) first spin-coating the perovskite precursor solution, and then spin-coating the counter solution to obtain a perovskite wet film;

[0009] (3) Annealing the perovskite wet film to obtain a perovskite thin film, wherein the perovskite thin film contains a perovskite structural substance.

[0010] In one or more embodiments, in step (1), the concentration of the theoretically generated perovskite structured substance in the perovskite precursor solution is 1.5-2.0 mol / L.

[0011] In one or more embodiments, in step (1), the solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, dichloromethane, methanol, isopropanol and ethanol.

[0012] In one or more embodiments, in step (1), the inorganic nanoparticles are selected from one or more of silicon oxide, aluminum oxide, silicon nitride, silicon carbide and magnesium oxide.

[0013] In one or more embodiments, in step (1), the particle size of the inorganic nanoparticles is 1-500 nm.

[0014] In one or more embodiments, in step (1), the inorganic nanoparticles are of a single particle size or have a particle size distribution.

[0015] In one or more embodiments, in step (1), the type of the inorganic nanoparticles is selected from one or more of solid particles, through-pore particles, mesoporous particles and hollow particles.

[0016] In one or more embodiments, in step (1), the anti-solvent is selected from one or more of anisole, ethyl acetate and chlorobenzene.

[0017] In one or more embodiments, in step (1), the concentration of the inorganic nanoparticles in the counter solution is 0.05 wt.%-0.5 wt.%.

[0018] In one or more embodiments, in step (2), the amount of the spin-coated perovskite precursor solution is 30-200 μL.

[0019] In one or more embodiments, in step (2), the amount of the counter solution for spin coating is 150-1000 μL.

[0020] In one or more embodiments, in step (3), the annealing temperature is 80-200°C.

[0021] In one or more embodiments, in step (3), the annealing time is 10-120 min.

[0022] In one or more embodiments, in step (3), the chemical formula of the perovskite structured material is ABX3, A is a monovalent cation, including but not limited to one or more of cesium ion, rubidium ion, methylamine ion and formamidine ion; B is a divalent cation, including but not limited to one or more of lead ion, copper ion, zinc ion, gallium ion, tin ion and calcium ion; X is a monovalent anion, including but not limited to one or more of iodide ion, bromide ion, chloride ion, fluoride ion, thiocyanate ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion and acetate ion.

[0023] The invention provides a perovskite film prepared by the method described in the invention.

[0024] In one or more embodiments, the perovskite film has a thickness of 100-10000 nm.

[0025] The present invention provides a photovoltaic device comprising the perovskite film of the present invention.

[0026] In one or more embodiments, the perovskite thin film is formed on a planar substrate or a textured substrate with a roughness of 200 nm to 800 nm.

[0027] Compared with the prior art, the present invention has the following beneficial effects: when preparing perovskite devices by reverse solution spin coating, using an anti-solvent containing inorganic nanoparticles can significantly improve the crystallization quality of the perovskite film, prevent the perovskite from peeling off from the substrate or generating holes, thereby improving the performance and yield of the perovskite stacked device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of the structure of a single-junction perovskite solar cell prepared according to some embodiments of the present invention.

[0029] Figure 2 Schematic diagram of the structure of a tandem perovskite solar cell prepared according to some embodiments of the present invention. DETAILED DESCRIPTION

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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).

[0034] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0035] 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.

[0036] 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.

[0037] The method for preparing a perovskite film of the present invention comprises the following steps:

[0038] (1) mixing a raw material of a perovskite structure material and a solvent to obtain a perovskite precursor solution; mixing inorganic nanoparticles and an anti-solvent to obtain an anti-solution;

[0039] (2) first spin-coating the perovskite precursor solution, and then spin-coating the counter solution to obtain a perovskite wet film;

[0040] (3) Annealing the perovskite wet film to obtain a perovskite thin film, wherein the perovskite thin film contains a perovskite structural substance.

[0041] In the present invention, the inorganic nanoparticles are insulating inorganic nanoparticles.

[0042] In the present invention, inorganic nanoparticles are uniformly distributed in the perovskite wet film. Since the inorganic nanoparticles have the property of stable insulation, the perovskite film will not produce additional defects. Since the inorganic nanoparticles have groups such as hydroxyl groups on the surface, during the annealing process of the perovskite wet film, the inorganic nanoparticles act as crystal nuclei to induce the perovskite to crystallize and grow, thereby improving the uniformity and crystal quality of the perovskite film. Since the crystal nuclei are uniformly distributed in the perovskite wet film, the contact and stress between the perovskite film and the substrate (especially the rough substrate) are significantly improved, thereby improving the photoelectric performance and stability of the perovskite device.

[0043] In step (1), in the perovskite precursor solution, the concentration of the theoretically generated perovskite structure material can be 1.5-2.0 mol / L, such as 1.5 mol / L, 1.6 mol / L, 1.7 mol / L, 1.8 mol / L, 1.9 mol / L, 2.0 mol / L. In step (1), the solvent can include, but is not limited to, one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), dichloromethane, methanol, isopropanol, and ethanol.

[0044] In step (1), the inorganic nanoparticles may be one or more selected from silicon oxide, aluminum oxide, silicon nitride, silicon carbide and magnesium oxide. In the present invention, when the perovskite device is prepared by the reverse solution spin coating method, the reverse solution containing inorganic nanoparticles is used to significantly improve the crystallization quality of the perovskite film, prevent the perovskite from peeling off from the substrate or generating holes, thereby improving the photoelectric performance and yield of the perovskite stacked device.

[0045] In step (1), the particle size of the inorganic nanoparticles can be 1-500nm, preferably 10-200nm, such as 10nm, 50nm, 100nm, 150nm, 200nm. In the present invention, the particle size of the inorganic nanoparticles is controlled within the above range, which is conducive to improving the photoelectric performance of the perovskite solar cell. In the present invention, the inorganic nanoparticles can be of a single particle size or have a certain particle size distribution. In step (1), the type of the inorganic nanoparticles can be one or more selected from solid particles, through-hole particles, mesoporous particles and hollow particles. In the present invention, perovskite grows in the inorganic nanoparticle sphere, and the different mesoporous forms of the inorganic nanoparticles have a certain influence on the carrier transfer rate generated by the perovskite, thereby affecting the photoelectric performance of the perovskite solar cell.

[0046] In step (1), the anti-solvent can be one or more selected from anisole, ethyl acetate and chlorobenzene. In the anti-solvent of the present invention, the concentration of the inorganic nanoparticles can be 0.05wt.%-0.5wt.%, such as 0.05wt.%, 0.10wt.%, 0.15wt.%, 0.20wt.%, 0.25wt.%, 0.30wt.%, 0.35wt.%, 0.40wt.%, 0.45wt.%, 0.50wt.%. In the present invention, controlling the concentration of the inorganic nanoparticles within the above range is beneficial to improving the photoelectric performance of the perovskite solar cell.

[0047] In step (2), the amount of the spin-coated perovskite precursor solution can be 30-200 μL, such as 30 μL, 50 μL, 70 μL, 100 μL, 120 μL, 140 μL, 160 μL, 180 μL, 200 μL. In step (2), the amount of the spin-coated counter solution can be 150-1000 μL, such as 200 μL, 300 μL, 400 μL, 500 μL, 600 μL, 700 μL, 800 μL, 900 μL, 1000 μL.

[0048] In step (3), the annealing temperature can be 80-200° C., for example, 80° C., 90° C., 100° C., 110° C., 120° C., 130° C., 140° C., 150° C., 160° C., 170° C., 180° C., 190° C., 200° C. In step (3), the annealing time can be 10-120 min, for example, 10 min, 20 min, 30 min, 40 min, 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, 110 min, 120 min.

[0049] In the present invention, the chemical formula of the perovskite structure material is ABX3, where A is a monovalent cation, which may include but is not limited to a cesium ion (Cs + ), rubidium ions (Rb + ), methylamine ion (CH3NH3 + , M.A. + ) and formamidinium ion (CH(NH2)2 + , F.A. + ) one or more; B is a divalent cation, which may include but is not limited to lead ions (Pb 2+ ), copper ions (Cu 2+ ), zinc ion (Zn 2+ ), gallium ions (Ga 2+ ), tin ions (Sn 2+ ) and calcium ions (Ca 2+ ) one or more; X is a monovalent anion, which may include but is not limited to iodide ion (I - ), bromide ion (Br - ), chloride ion (Cl - ), fluoride ion (F - ), thiocyanate ion (SCN - ), tetrafluoroborate ion (BF4 - ) and hexafluorophosphate ion (PF6 -), formate ion (COO-) and acetate ion (CH3COO-) one or more. In the present invention, the thickness of the perovskite film can be 100-10000nm, such as 100nm, 500nm, 1000nm, 2000nm, 3000nm, 4000nm, 5000nm, 6000nm, 7000nm, 8000nm, 9000nm, 10000nm. The photovoltaic device of the present invention can include a single-junction perovskite solar cell or a stacked perovskite solar cell.

[0050] In the present invention, the perovskite film can be formed on a planar substrate or on a velvet substrate with a roughness of 200nm-800nm. In some embodiments, the roughness of the planar substrate is 0. The present invention uses an anti-solvent containing inorganic nanoparticles to form a perovskite film on a planar substrate and a rough velvet substrate. At this time, the inorganic nanoparticles in the anti-solvent will serve as perovskite nucleation sites, promote uniform film formation of perovskite, reduce interface defect density, improve the quality of the perovskite film, and thus improve device performance. Further, when a perovskite film is formed on a rough velvet substrate, an uneven crystallization rate will occur, which will cause excessive stress on the bottom surface, and the perovskite film will be easily peeled off from the bottom interface or form holes, thereby seriously affecting the performance and stability of the perovskite device. Therefore, the use of the anti-solvent containing inorganic nanoparticles of the present invention is more significant in improving the film quality of the perovskite film formed on the rough velvet substrate, and the improvement of the performance of the corresponding photovoltaic device is also more significant.

[0051] The photovoltaic device of the present invention may include a formal perovskite solar cell or an inverted perovskite solar cell. The photovoltaic device of the present invention may be a formal single-junction perovskite solar cell, an inverted single-junction perovskite solar cell, a formal tandem perovskite solar cell or an inverted tandem perovskite solar cell. In the present invention, the perovskite film of the single-junction perovskite solar cell is formed on a planar substrate. In the present invention, the perovskite film of the tandem perovskite solar cell is formed on a rough velvet substrate. The present invention improves the photoelectric performance and stability of single-junction perovskite solar cells and tandem perovskite solar cells comprising a perovskite film prepared using an anti-solvent containing inorganic nanoparticles of the present invention, and the improvement of the photoelectric performance and stability of the tandem perovskite solar cell is more significant.

[0052] In the present invention, the formal single-junction perovskite solar cell may include a transparent conductive substrate, an electron transport layer, a perovskite film, a hole transport layer and a back electrode in sequence.

[0053] In the present invention, the inverted single junction perovskite solar cell may include a transparent conductive substrate, a hole transport layer, a perovskite film, an electron transport layer and a back electrode in sequence. In the present invention, the inverted single junction perovskite solar cell may further include a hole blocking layer, which is between the electron transport layer and the back electrode. In the present invention, the inverted single junction perovskite solar cell may further include a passivation layer, which is between the perovskite film and the electron transport layer. In some embodiments, the inverted single junction perovskite solar cell includes a transparent conductive substrate, a hole transport layer, a perovskite film, a passivation layer, an electron transport layer, a hole blocking layer and a back electrode in sequence.

[0054] In the present invention, the formal stacked perovskite solar cell may include a bottom electrode, a bottom cell, an intermediate layer, a formal perovskite top cell and a top electrode in sequence, and the positive electrode top cell may include an electron transport layer, a perovskite film and a hole transport layer in sequence.

[0055] In the present invention, the inverted stacked perovskite solar cell may include a bottom electrode, a bottom cell, an intermediate layer, an inverted perovskite top cell and a top electrode in sequence, and the inverted top cell may include a hole transport layer, a perovskite film and an electron transport layer in sequence. In the present invention, the inverted stacked perovskite solar cell may further include a hole blocking layer, which is between the electron transport layer and the top electrode. In the present invention, the inverted stacked perovskite solar cell may further include a passivation layer, which is between the perovskite film and the electron transport layer. In some embodiments, the inverted top cell of the inverted stacked perovskite solar cell includes a hole transport layer, a perovskite film, a passivation layer, an electron transport layer and a hole blocking layer in sequence.

[0056] In the present invention, the transparent conductive substrate may be an indium tin oxide (ITO) substrate, a fluorine-doped tin oxide (FTO) substrate or an indium zinc oxide (IZO) substrate.

[0057] In the present invention, the hole transport layer can be an inorganic transport material and / or an organic p-type semiconductor material. In the present invention, the inorganic transport material can be one or more selected from nickel oxide (NiO), cuprous oxide (Cu2O), molybdenum oxide (MoO3), copper iodide (CuI) and redox graphene. In the present invention, the organic p-type semiconductor material can be one or more selected from poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA, poly(triaryl amine)), 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD), poly-3,4-ethylenedioxythiophene:polystyrene sulfonate (PEDOT:PSS), poly[bis(4-phenyl)(4-butylphenyl)amine] (Ploy-TPD), [4-(3,6-dimethyl-9H-carbazole-9-yl)butyl]phosphonic acid (Me-4PACz), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid and [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid. In the present invention, the thickness of the hole transport layer can be 1-100 nm, for example, 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 60 nm, 100 nm.

[0058] In the present invention, the electron transport layer may be an n-type semiconductor material. In the present invention, the n-type semiconductor material may be one or more selected from titanium oxide (TiO2), tin oxide (SnO2), zinc oxide (ZnO), fullerene (C60), graphene, and fullerene derivatives (PCBM). In the present invention, the thickness of the electron transport layer may be 1-100nm, for example, 1nm, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 60nm, 100nm.

[0059] In the present invention, the back electrode may be one or more selected from the group consisting of gold, palladium, silver, titanium, chromium, nickel, aluminum, copper, indium tin oxide (ITO) and indium zinc oxide (IZO).

[0060] In the present invention, the top electrode may include a transparent electrode layer; preferably, the top electrode may also include a metal grid line; more preferably, the top electrode may also include an anti-reflection layer.

[0061] In the present invention, the intermediate layer may be indium tin oxide (ITO).

[0062] In the present invention, the bottom cell may be a crystalline silicon bottom cell, a perovskite bottom cell, a copper indium gallium selenide bottom cell, a cadmium telluride bottom cell or an organic bottom cell.

[0063] In the present invention, the bottom electrode may include a transparent electrode layer; preferably, the bottom electrode may also include a metal grid line.

[0064] In the present invention, the transparent electrode layer may be indium tin oxide (ITO) and / or indium zinc oxide (IZO).

[0065] In the present invention, the metal gate line may be one or more selected from Ag, Au and Cu.

[0066] The present invention provides a method for preparing a formal single-junction perovskite solar cell, which may include the following steps:

[0067] (1) depositing an electron transport layer on the surface of a transparent conductive substrate;

[0068] (2) depositing a perovskite film on the surface of the electron transport layer;

[0069] (3) depositing a hole transport layer on the surface of the perovskite film;

[0070] (4) A back electrode is deposited on the surface of the hole transport layer to obtain a formal single-junction perovskite solar cell.

[0071] The present invention provides a method for preparing an inverted single-junction perovskite solar cell, which may include the following steps:

[0072] (1) depositing a hole transport layer on the surface of a transparent conductive substrate;

[0073] (2) depositing a perovskite film on the surface of the hole transport layer;

[0074] (3) depositing an electron transport layer on the surface of the perovskite film;

[0075] (4) A back electrode is deposited on the surface of the electron transport layer to obtain an inverted single-junction perovskite solar cell.

[0076] The present invention provides a method for preparing a formal tandem perovskite solar cell, which may include the following steps:

[0077] (1) Depositing the bottom electrode and the intermediate layer on both sides of the bottom cell;

[0078] (2) depositing an electron transport layer on the surface of the intermediate layer;

[0079] (3) depositing a perovskite film on the surface of the electron transport layer;

[0080] (4) depositing a hole transport layer on the surface of the perovskite film;

[0081] (5) Depositing a top electrode on the surface of the hole transport layer to obtain a formal laminated perovskite solar cell.

[0082] The present invention provides a method for preparing an inverted stacked perovskite solar cell, which may include the following steps:

[0083] (1) Depositing the bottom electrode and the intermediate layer on both sides of the bottom cell;

[0084] (2) depositing a hole transport layer on the surface of the intermediate layer;

[0085] (3) depositing a perovskite film on the surface of the hole transport layer;

[0086] (4) depositing an electron transport layer on the surface of the perovskite film;

[0087] (5) A top electrode is deposited on the surface of the electron transport layer to obtain an inverted stacked perovskite solar cell.

[0088] In the present invention, the electron transport layer can be deposited by electron beam evaporation, thermal evaporation, magnetron sputtering, atomic layer deposition, spin coating or doctor blade coating.

[0089] 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.

[0090] The polyvinyl pyrrolidone in the comparative example of the present invention was purchased from Aladdin, CAS No.: 9003-39-8, and the average molecular weight was 8000.

[0091] Example 1

[0092] In this embodiment, the structure is prepared as Figure 1 The single-junction perovskite solar cell shown in the figure has the following specific steps:

[0093] (1) using an ITO cleaning agent, deionized water, acetone, and isopropyl alcohol (IPA) to ultrasonically treat an ITO glass substrate for 15 minutes in sequence to obtain a clean ITO glass substrate;

[0094] (2) A NiOx layer with a thickness of 15 nm was prepared on the front side of a clean ITO glass substrate by magnetron sputtering; a SAM layer with a thickness of 3 nm was prepared on the surface of the NiOx layer by a one-step spin coating method, wherein the material of the SAM layer was Me-4PACz, and the surface roughness of the SAM layer was consistent with that of the glass substrate, and the surface roughness was 0; the NiOx layer and the SAM layer together constituted a hole transport layer;

[0095] (3) A raw material of a perovskite structure material and a mixed solvent (a mixed solvent in which the volume ratio of DMF and DMSO is 4:1) are mixed to obtain a perovskite precursor solution, in which the concentration of the theoretically generated perovskite structure material is 1.5 mol / L; silicon oxide nanoparticles (solid particles) with a particle size of 30 nm and anisole are mixed to obtain a reverse solution with a silicon oxide nanoparticle concentration of 0.2 wt.%; 100 μl of the perovskite precursor solution is first spin-coated on the surface of the hole transport layer, and then 300 μl of the reverse solution is spin-coated to obtain a perovskite wet film; the perovskite wet film is annealed at 100° C. for 20 min to obtain a 1200 nm thick perovskite structure material Cs 0.05 MA 0.15 FA 0.80 Pb(I 0.75 Br 0.25 )3 perovskite film;

[0096] (4) a passivation layer with a thickness of 0.5 nm is prepared on the surface of the perovskite film by a one-step spin coating method, wherein the material of the passivation layer is 1,3-diaminopropane dihydroiodide (PDADI), and the solvent in the passivation layer preparation process is isopropyl alcohol (IPA);

[0097] (5) preparing an electron transport layer with a thickness of 15 nm and made of C60 on the surface of the passivation layer by thermal evaporation;

[0098] (6) preparing a hole blocking layer with a thickness of 6 nm and made of BCP on the surface of the electron transport layer by thermal evaporation;

[0099] (7) A back electrode with a thickness of 150 nm and a material of Ag was prepared on the surface of the hole blocking layer by a thermal evaporation method, and a single-junction perovskite solar cell was obtained.

[0100] Example 2

[0101] In this embodiment, the structure is prepared as Figure 2 The stacked perovskite solar cell shown in the figure has the following specific steps:

[0102] (1) sputtering an ITO intermediate layer on a p-type crystalline silicon substrate with a velvet pyramid structure and a roughness of 400 nm;

[0103] (2) A NiOx layer with a thickness of 15 nm was prepared on the front of a clean ITO glass substrate by magnetron sputtering; a SAM layer with a thickness of 3 nm was prepared on the surface of the NiOx layer by a one-step spin coating method, wherein the material of the SAM layer was Me-4PACz, and the surface roughness of the SAM layer was consistent with that of the suede silicon substrate, and the surface roughness was 400 nm; the NiOx layer and the SAM layer together constituted a hole transport layer;

[0104] (3) A raw material of a perovskite structure material and a mixed solvent (a mixed solvent in which the volume ratio of DMF and DMSO is 4:1) are mixed to obtain a perovskite precursor solution, in which the concentration of the theoretically generated perovskite structure material is 1.7 mol / L; silicon oxide nanoparticles (solid particles) with a particle size of 30 nm and anisole are mixed to obtain a reverse solution in which the concentration of silicon oxide nanoparticles is 0.2 wt.%; 100 μL of the perovskite precursor solution is first spin-coated on the surface of the hole transport layer, and then 300 μL of the reverse solution is spin-coated to obtain a perovskite wet film; the perovskite wet film is annealed at 100° C. for 20 min to obtain a 1200 nm thick perovskite structure material having a Cs 0.05 MA 0.15 FA 0.80 Pb(I 0.75 Br 0.25 )3 perovskite film;

[0105] (4) a passivation layer with a thickness of 0.5 nm is prepared on the surface of the perovskite film by a one-step spin coating method, wherein the material of the passivation layer is 1,3-diaminopropane dihydroiodide (PDADI), and the solvent in the passivation layer preparation process is isopropyl alcohol (IPA);

[0106] (5) preparing an electron transport layer with a thickness of 15 nm and made of C60 on the surface of the passivation layer by thermal evaporation;

[0107] (6) using a thermal evaporation method to prepare a hole blocking layer with a thickness of 15 nm and made of SnO2 on the electron transport layer;

[0108] (7) A transparent electrode layer with a thickness of 50 nm and made of IZO is prepared on the surface of the hole blocking layer by magnetron sputtering; a metal grid line with a thickness of 200 nm and made of Ag is prepared on the surface of the transparent electrode layer by thermal evaporation; the transparent electrode and the metal grid line together constitute the top electrode; a metal grid line with a thickness of 400 nm and made of Ag is prepared on the bottom surface of the silicon cell by thermal evaporation; and a stacked perovskite solar cell is obtained at the same time.

[0109] Example 3

[0110] The only difference between this embodiment and embodiment 1 is that the concentration of silicon oxide nanoparticles in the counter solution of this embodiment is 0.05 wt.%.

[0111] Example 4

[0112] The only difference between this embodiment and embodiment 1 is that the concentration of silicon oxide nanoparticles in the counter solution of this embodiment is 0.5 wt.%.

[0113] Example 5

[0114] The only difference between this embodiment and embodiment 2 is that the concentration of silicon oxide nanoparticles in the counter solution of this embodiment is 0.05 wt.%.

[0115] Example 6

[0116] The only difference between this embodiment and embodiment 2 is that the concentration of silicon oxide nanoparticles in the counter solution of this embodiment is 0.5 wt.%.

[0117] Example 7

[0118] The only difference between this embodiment and embodiment 2 is that the particle size of the silicon oxide nanoparticles in the counter solution of this embodiment is 100 nm.

[0119] Example 8

[0120] The only difference between this embodiment and embodiment 2 is that the particle size of the silicon oxide nanoparticles in the counter solution of this embodiment is 500 nm.

[0121] Comparative Example 1

[0122] The difference between this comparative example and Example 1 is that the anti-solvent in this comparative example only contains the anti-solvent itself and does not contain inorganic nanoparticles.

[0123] Comparative Example 2

[0124] The difference between this comparative example and Example 2 is that the anti-solvent in this comparative example only contains the anti-solvent itself and does not contain inorganic nanoparticles.

[0125] Comparative Example 3

[0126] The difference between this comparative example and Example 2 is that: Step (3) of this comparative example is to mix the raw material of the perovskite structure material, silicon oxide nanoparticles (solid particles) with a particle size of 30 nm and a mixed solvent (a mixed solvent in which the volume ratio of DMF and DMSO is 4:1) to obtain a perovskite precursor solution, in which the concentration of the theoretically generated perovskite structure material is 1.7 mol / L, and the concentration of the silicon oxide nanoparticles is 0.2 wt.%; firstly, 100 microliters of the perovskite precursor solution is spin-coated on the surface of the hole transport layer, and then 300 microliters of spin-coated anisole anti-solvent are spin-coated to obtain a perovskite wet film; and the perovskite wet film is annealed at 100° C. for 20 min to obtain a perovskite structure material having a thickness of 1200 nm and a perovskite structure material of Cs 0.05 MA 0.15 FA 0.80 Pb(I 0.75 Br 0.25 )3 perovskite film.

[0127] Comparative Example 4

[0128] The only difference between this comparative example and Example 2 is that in this comparative example, 0.2 wt. % of silicon oxide nanoparticles in the counter solution are replaced by 0.2 wt. % of polyvinyl pyrrolidone nanoparticles.

[0129] Comparative Example 5

[0130] The difference between this example and Example 1 is that the concentration of silicon oxide nanoparticles in the counter solution of this comparative example is 1.0 wt.%.

[0131] Comparative Example 6

[0132] The only difference between this example and Example 2 is that the concentration of silicon oxide nanoparticles in the counter solution of this comparative example is 1.0 wt.%.

[0133] Comparative Example 7

[0134] The only difference between this example and Example 2 is that the particle size of the silicon oxide nanoparticles in the counter solution of this comparative example is 800 nm.

[0135] Comparative Example 8

[0136] The difference between this comparative example and Example 1 is that: Step (3) of this comparative example is to mix the raw material of the perovskite structure material, silicon oxide nanoparticles (solid particles) with a particle size of 30 nm and a mixed solvent (a mixed solvent in which the volume ratio of DMF and DMSO is 4:1) to obtain a perovskite precursor solution, in which the concentration of the theoretically generated perovskite structure material is 1.7 mol / L, and the concentration of the silicon oxide nanoparticles is 0.2 wt.%; firstly, 100 microliters of the perovskite precursor solution is spin-coated on the surface of the hole transport layer, and then 300 microliters of spin-coated anisole anti-solvent are spin-coated to obtain a perovskite wet film; and the perovskite wet film is annealed at 100° C. for 20 min to obtain a perovskite structure material having a thickness of 1200 nm and Cs 0.05 MA 0.15 FA 0.80 Pb(I 0.75 Br 0.25 )3 perovskite film.

[0137] Test Case

[0138] Device performance test of perovskite solar cells: Under 25°C and AM 1.5G standard solar spectrum, a solar simulator was used to set the voltage range to -0.3V-2.0V, and the current output of the perovskite solar cells prepared in Examples 1-8 and Comparative Examples 1-8 at different voltages was tested, and the corresponding current-voltage (IV) characteristic curves were plotted. The surface area of ​​the single-junction perovskite solar cell was 0.04cm 2 The surface area of ​​the tandem perovskite solar cell is 1.1664cm 2, the incident light power (Pin) is 100mWcm -2 The open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of the perovskite solar cells prepared in Examples 1-8 and Comparative Examples 1-8 were obtained according to the characteristic curves.

[0139] (1) Open circuit voltage (Voc): The voltage value corresponding to when the current is equal to zero.

[0140] (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.

[0141] (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.

[0142] (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%.

[0143] The test results of the open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of the perovskite solar cells prepared in Examples 1-8 and Comparative Examples 1-8 are shown in Table 1.

[0144] Table 1: Open circuit voltage, short circuit current density, fill factor and photoelectric conversion efficiency of perovskite solar cells prepared in Examples 1-8 and Comparative Examples 1-8

[0145] <![CDATA[V OC (V)]]> <![CDATA[J SC (mA / cm 2 )]]> FF(%) PCE(%) Example 1 1.263 21.01 84.3 22.36 Example 2 1.981 20.36 82.4 33.23 Example 3 1.256 20.93 83.2 21.87 Example 4 1.253 20.97 83.4 21.91 Example 5 1.974 20.32 81.7 32.77 Example 6 1.970 20.34 81.9 32.81 Example 7 1.976 20.31 82.1 32.94 Example 8 1.965 20.24 81.2 32.29 Comparative Example 1 1.245 20.68 82.9 21.35 Comparative Example 2 1.953 20.15 80.3 31.60 Comparative Example 3 1.962 20.21 80.6 31.95 Comparative Example 4 1.941 20.03 79.6 30.94 Comparative Example 5 1.250 20.87 83.1 21.67 Comparative Example 6 1.968 20.25 80.9 32.24 Comparative Example 7 1.911 20.05 75.2 28.81 Comparative Example 8 1.251 20.91 83.2 21.76

Claims

1. A method for preparing a perovskite film, characterized in that: The method comprises the following steps: (1) mixing a raw material of a perovskite structure material and a solvent to obtain a perovskite precursor solution; mixing inorganic nanoparticles and an anti-solvent to obtain an anti-solution; (2) first spin-coating the perovskite precursor solution, and then spin-coating the counter solution to obtain a perovskite wet film; (3) Annealing the perovskite wet film to obtain a perovskite thin film, wherein the perovskite thin film contains a perovskite structural substance.

2. The method according to claim 1, characterized in that In step (1), the concentration of the theoretically generated perovskite structure substance in the perovskite precursor solution is 1.5-2.0 mol / L; and / or In step (1), the solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, dichloromethane, methanol, isopropanol and ethanol.

3. The method according to claim 1, characterized in that The method has one or more of the following features: In step (1), the inorganic nanoparticles are selected from one or more of silicon oxide, aluminum oxide, silicon nitride, silicon carbide and magnesium oxide; In step (1), the particle size of the inorganic nanoparticles is 1-500 nm; In step (1), the inorganic nanoparticles have a single particle size or a particle size distribution; In step (1), the type of the inorganic nanoparticles is selected from one or more of solid particles, through-pore particles, mesoporous particles and hollow particles.

4. The method according to claim 1, characterized in that In step (1), the anti-solvent is selected from one or more of anisole, ethyl acetate and chlorobenzene; and / or In step (1), the concentration of the inorganic nanoparticles in the counter solution is 0.05wt.%-0.5wt.%.

5. The method according to claim 1, characterized in that In step (2), the amount of the spin-coated perovskite precursor solution is 30-200 μL; and / or In step (2), the amount of the counter solution used for spin coating is 150-1000 μL.

6. The method according to claim 1, characterized in that The method has one or more of the following features: In step (3), the annealing temperature is 80-200°C; In step (3), the annealing time is 10-120 min; In step (3), the chemical formula of the perovskite structure material is ABX3, A is a monovalent cation, including but not limited to one or more of cesium ion, rubidium ion, methylamine ion and formamidine ion; B is a divalent cation, including but not limited to one or more of lead ion, copper ion, zinc ion, gallium ion, tin ion and calcium ion; X is a monovalent anion, including but not limited to one or more of iodide ion, bromide ion, chloride ion, fluoride ion, thiocyanate ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion and acetate ion.

7. A perovskite film prepared by the method according to any one of claims 1 to 6.

8. The perovskite film according to claim 7, characterized in that The thickness of the perovskite film is 100-10000 nm.

9. A photovoltaic device comprising the perovskite thin film according to claim 7 or 8.

10. The photovoltaic device according to claim 9, characterized in that: The perovskite film is formed on a flat substrate or a velvet substrate with a roughness of 200nm-800nm.

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