Perovskite precursor solution, perovskite thin film, perovskite solar cell and preparation method

Abstract

The invention belongs to the photovoltaic field, and particularly relates to a perovskite precursor solution, a perovskite thin film, a perovskite solar cell and a preparation method. The method for preparing the perovskite precursor solution comprises the following steps: mixing a perovskite structure substance raw material with a solvent, then adding tetraethyl silicate, mixing, and filtering to obtain the perovskite precursor solution. The tetraethyl silicate is added in the preparation process of the perovskite precursor solution, so that the defects of the perovskite thin film can be passivated, and the photoelectric property and the stability of the perovskite solar cell are improved.

Description

Technical Field

[0001] The present invention belongs to the field of photovoltaics, and particularly relates to a perovskite precursor solution, a perovskite thin film, a perovskite solar cell and a preparation method thereof. Background Art

[0002] In the past decade or so, perovskite solar cells have greatly attracted the attention of researchers, and their power conversion efficiency has soared from 3.8% to 26.1%. Due to the advantages of low cost, simple manufacturing process, and high performance of perovskite solar devices, they are expected to become one of the most promising photovoltaic technologies in the future. However, the degradation and instability of perovskite thin films have hindered their commercialization process. Achieving a long lifespan for perovskite solar cells remains a huge challenge. The moisture in perovskite devices, as one of the factors affecting stability, cannot be ignored.

[0003] On the one hand, there will inevitably be some residual moisture in common drugs and solvents, and the presence of this moisture will affect the performance of perovskite solar cells; on the other hand, the crystal structure of perovskite is easily damaged by the intrusion of moisture, which will lead to a sharp decline in the overall performance of perovskite solar cells.

[0004] Therefore, there is an urgent need to develop a method to remove moisture in perovskite solar cells, thereby improving the optoelectronic performance and stability of perovskite solar cells. Summary of the Invention

[0005] To solve the problems existing in the prior art, the present invention provides a perovskite precursor solution, a perovskite thin film, a perovskite solar cell and a preparation method thereof. By adding tetraethyl orthosilicate (TEOS), most of the moisture in the perovskite precursor solution is removed; at the same time, the oligomeric silica obtained by the hydrolysis of tetraethyl orthosilicate can passivate the defects on the surface and grain boundaries synchronously, stabilize the perovskite grains, and thereby improve the optoelectronic performance and stability of perovskite solar cells.

[0006] Specifically, the present invention provides a method for preparing a perovskite precursor solution, which includes mixing raw materials of perovskite structure substances and a solvent, then adding tetraethyl orthosilicate and mixing, and filtering to obtain the perovskite precursor solution.

[0007] In one or more embodiments, the raw materials of perovskite structure substances are AX and BX2, the A ion is selected from one or more of cesium ion, rubidium ion, methylamine ion and formamidinium ion; the B ion is lead ion and / or tin ion; the X ion is selected from one or more of iodide ion, bromide ion and chloride ion.

[0008] In one or more embodiments, the solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide and N-methylpyrrolidone.

[0009] In one or more embodiments, the addition amount of tetraethyl orthosilicate in the perovskite precursor solution is 5 - 20 μL / mL of solvent.

[0010] In one or more embodiments, in the perovskite precursor solution, the concentration of B ions is 1.0 - 1.6 mol / L.

[0011] In one or more embodiments, A ions are selected from one or more of cesium ions, methylamine ions, and formamidinium ions; B ions are lead ions; X ions are iodide ions and / or bromide ions.

[0012] The present invention provides a perovskite precursor solution prepared by the method described in any one of the embodiments herein.

[0013] The present invention provides a method for preparing a perovskite thin film, the method comprising: coating the perovskite precursor solution of the present invention and annealing to obtain a perovskite thin film.

[0014] In one or more embodiments, the perovskite precursor solution is coated by spin coating or blade coating.

[0015] In one or more embodiments, the annealing temperature is 100 - 120 °C.

[0016] In one or more embodiments, the annealing time is 20 - 30 min.

[0017] The present invention provides a perovskite thin film prepared by the method of the present invention.

[0018] In one or more embodiments, the thickness of the perovskite thin film is 400 - 1200 nm.

[0019] In one or more embodiments, the perovskite thin film contains a perovskite structure substance, and the chemical formula of the perovskite structure substance is ABX3, where A ions are selected from one or more of cesium ions, rubidium ions, methylamine ions, and formamidinium ions; B ions are lead ions and / or tin ions; X ions are selected from one or more of iodide ions, bromide ions, and chloride ions.

[0020] In one or more embodiments, the perovskite structure substance is FA a MA b Cs c Pb(I m Br n )3, a + b + c = 1, m + n = 1, 0 < c < 0.3, 0 < a < 1, 0 < b < 1; preferably, a:(b + c) = 1:(0 - 0.25).

[0021] The present invention provides a perovskite solar cell comprising the perovskite thin film of the present invention. Description of the Drawings

[0022] Figure 1 (a) Schematic structural diagram of a formal single-junction perovskite solar cell prepared according to some embodiments of the present invention. Figure 1 (b) Schematic structural diagram of an inverted single-junction perovskite solar cell prepared according to some embodiments of the present invention.

[0023] Figure 2 Schematic structural diagram of an inverted tandem perovskite solar cell prepared according to some embodiments of the present invention.

[0024] Figure 3 Stability test curves of the perovskite solar cells prepared in Example 4 and Comparative Example 1 of the present invention.

[0025] Figure 4 Stability test curves of the perovskite solar cells prepared in Example 5 and Comparative Example 2 of the present invention.

[0026] Figure 5 Stability test curves of the perovskite solar cells prepared in Example 6 and Comparative Example 3 of the present invention. Detailed Description of the Invention

[0027] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meaning understood by those skilled in the art regarding the present invention. In case of conflicts, the definitions in this specification shall prevail.

[0028] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not limit the scope of the present invention in any way, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0029] In this document, terms such as "comprising", "including", "containing" and similar terms cover the meanings of "consisting essentially of" and "consisting of". For example, when this document discloses that "A comprises B and C", it should be considered that "A consists essentially of B and C" and "A consists of B and C" have been disclosed herein.

[0030] In this document, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values (including integers and fractions) within the ranges.

[0031] In this document, unless otherwise specified, percentages refer to mass percentages and ratios refer to mass ratios.

[0032] In this text, when describing embodiments or examples, it should be understood that it is not intended to limit the present invention to these embodiments or examples. On the contrary, all alternatives, improvements, and equivalents of the methods and materials described in the present invention can be covered within the scope defined by the claims.

[0033] In this text, for the sake of brevity of description, not all possible combinations of all technical features in each embodiment or example are described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered to be within the scope described in this specification.

[0034] The present invention provides a method for preparing a perovskite precursor solution. The method includes mixing a perovskite structure material raw material and a solvent, then adding tetraethyl orthosilicate and mixing, and filtering to obtain the perovskite precursor solution. In the present invention, because tetraethyl orthosilicate is added during the preparation of the perovskite precursor solution, tetraethyl orthosilicate can react with water to generate (-SiO2-)n and C2H5OH. When n in (-SiO2-)n is small, it is oligomeric silica, and when the n value is large, it is a precipitate. At this time, most of the water in the perovskite precursor solution can be removed. The oligomeric silica will wrap the perovskite grains and play a stabilizing role on the perovskite grains. At the same time, an excessive amount of tetraethyl orthosilicate is used to introduce the -OCH2CH3 group, and the -OCH2CH3 group can provide a lone pair of electrons to generate an electrostatic interaction with the uncoordinated Pb 2+ and the A-site cation to passivate defects and improve the optoelectronic performance of the device.

[0035] In the present invention, the perovskite structure material raw material can be AX and BX2. The A ion is a monovalent cation, and can include but is not limited to cesium ion (Cs + ), rubidium ion (Rb + ), methylammonium ion (CH3NH3 + , MA + ) and formamidinium ion (CH(NH2)2 + , FA + ) or one or more of them; the B ion is a divalent cation, and can include but is not limited to lead ion (Pb 2+ ) and / or tin ion (Sn 2+ ); the X ion is a monovalent anion, and can include but is not limited to iodide ion (I - ), bromide ion (Br - ) and chloride ion (Cl -One or more of those in ; preferably, among the raw materials of the perovskite structure substance, the A ions are selected from one or more of cesium ions, methylamine ions, and formamidine ions; the B ions are lead ions; the X ions are iodide ions and / or bromide ions. Using the preferably perovskite structure substance raw materials is beneficial to preparing a ternary mixed organic halogen hybrid perovskite structure substance, which has the most commercial prospects in terms of optoelectronic parameters and stability. In some embodiments, the perovskite structure substance raw materials are PbI2, FAI, MABr, and PbCl2.

[0036] In the present invention, the solvent can be one or more of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and N-methylpyrrolidone (NMP). In some embodiments, the solvent is a mixed solvent composed of N,N-dimethylformamide and dimethyl sulfoxide, and the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is (4-9):1, such as 4:1, 5:1, 6:1, 7:1, 8:1, 9:1.

[0037] In the present invention, the addition amount of tetraethyl orthosilicate in the perovskite precursor solution can be 5-20 μL / mL of the solvent, such as 5 μL / mL, 8 μL / mL, 10 μL / mL, 12 μL / mL, 14 μL / mL, 16 μL / mL, 18 μL / mL, 20 μL / mL. Using the above dosage of tetraethyl orthosilicate in the present invention is beneficial to obtaining a high-quality perovskite thin film and improving the optoelectronic performance and stability of the perovskite solar cell.

[0038] In the perovskite precursor solution of the present invention, the concentration of the B ions can be 1.0-1.6 mol / L, such as 1.0 mol / L, 1.1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L.

[0039] The present invention provides a method for preparing a perovskite thin film, the method includes coating the perovskite precursor solution of the present invention and annealing to obtain a perovskite thin film. In the present invention, the coating method of the perovskite precursor solution can be spin coating or blade coating; preferably, spin coating can be a one-step method or a two-step method. In a single-junction perovskite solar cell, the spin coating speed can be 3500-4500 rpm, and the spin coating time can be 35-40 s. An antisolvent can be dropped in the last 10 s to 15 s. In a tandem perovskite solar cell, spin coating is carried out in three steps. The parameter settings are 600-1000 rpm, 2-10 s for the first step, 2000-3000 rpm, 40-70 s for the second step, 5000-6000 rpm, 10-15 s for the third step. An antisolvent is dropped in the last 10-15 s, such as the parameter settings are 700 rpm, 5 s → 2000 rpm, 35 s → 5000 rpm, 10 s, and the antisolvent is dropped at the 42nd second.

[0040] In the present invention, the anti-solvent can be chlorobenzene and / or anisole and / or ethyl acetate.

[0041] In the present invention, the annealing temperature can be 100 - 120 °C, such as 100 °C, 105 °C, 110 °C, 115 °C, 120 °C. In the present invention, the annealing time can be 20 - 30 min, such as 20 min, 22 min, 24 min, 26 min, 28 min, 30 min.

[0042] The present invention provides a perovskite thin film prepared by the preparation method of the present invention. In the present invention, the thickness of the perovskite thin film can be 400 - 1200 nm, such as 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm. In a single-junction perovskite solar cell, the perovskite thickness can be 400 - 700 nm, such as 400 nm, 500 nm, 600 nm, 700 nm. In a tandem perovskite solar cell, the thickness of the perovskite thin film can be 800 - 1200 nm, such as 800 nm, 900 nm, 1000 nm, 1100 nm, 1200 nm.

[0043] In the present invention, the perovskite thin film can contain a perovskite structure substance, and the chemical formula of the perovskite structure substance is ABX3. The A ion is a monovalent cation and can include but is not limited to cesium ion (Cs + ), rubidium ion (Rb + ), methylammonium ion (CH3NH3 + , MA + ) and formamidinium ion (CH(NH2)2 + , FA + ) one or more of them; the B ion is a divalent cation and can include but is not limited to lead ion (Pb 2+ ) and / or tin ion (Sn 2+ ); the X ion is a monovalent anion and can include but is not limited to iodide ion (I - ), bromide ion (Br - ) and chloride ion (Cl - ) one or more of them. For example, the perovskite structure substance can be FA 0.83 Cs 0.17 Pb(I 0.8 Br 0.2 )3, FA 0.97 MA 0.03 Pb(I 0.97 Br 0.03 )3, MAPbI3, CsPbI3. In some embodiments, the perovskite structure substance is FAa MA b Cs c Pb(I m Br n )3, where a + b + c = 1, m + n = 1, 0 < c < 0.3, 0 < a < 1, 0 < b < 1; preferably, a:(b + c) = 1:(0 - 0.25). In some embodiments, the value of a:(b + c) is 1:0.01, 1:0.05, 1:0.1, 1:0.2, etc.

[0044] The present invention provides a perovskite solar cell comprising the perovskite thin film of the present invention. In the present invention, the perovskite solar cell may include a single-junction perovskite solar cell or a tandem perovskite solar cell; the perovskite solar cell may include a normal perovskite solar cell (n-i-p type perovskite solar cell) or an inverted perovskite solar cell (p-i-n type perovskite solar cell). Specifically, the perovskite solar cell may be a normal single-junction perovskite solar cell, an inverted single-junction perovskite solar cell, or a tandem perovskite solar cell.

[0045] In the present invention, the normal single-junction perovskite solar cell may sequentially include a transparent conductive substrate, an electron transport layer, a perovskite thin film, a hole transport layer, and a metal electrode. In the present invention, the inverted single-junction perovskite solar cell may sequentially include a transparent conductive substrate, a hole transport layer, a perovskite thin film, an electron transport layer, a hole blocking layer, and a metal electrode. In the present invention, the tandem perovskite solar cell may sequentially include a bottom electrode, a bottom cell, a tunneling layer, a perovskite top cell, and a top electrode, and the top cell may sequentially include a hole transport layer, a perovskite thin film, and an electron transport layer.

[0046] Compared with the prior art, the present invention has the following beneficial technical effects:

[0047] (1) In the present invention, the water content of the perovskite precursor solution with the introduction of tetraethyl orthosilicate is reduced, which is more convenient than removing water one by one for individual substances, and the stability of the prepared perovskite solar cell is improved;

[0048] (2) In the present invention, the oligomeric silica formed by the reaction of tetraethyl orthosilicate with water will wrap the perovskite grains and play a stabilizing role on the perovskite grains;

[0049] (3) In the present invention, the -OCH2CH3 groups formed by the reaction of tetraethyl orthosilicate with water can interact with the defects on the perovskite surface, passivate the charged defects, and improve the optoelectronic performance of the device.

[0050] The present invention will be described below by way of specific embodiments. It should be understood that these embodiments are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents, and materials used in the embodiments are conventional methods, reagents, and materials in the art unless otherwise specified. The starting compounds in the embodiments can all be obtained through commercial channels.

[0051] Example 1

[0052] This example prepares Figure 1 the formal single-junction perovskite solar cell shown in (a), and the specific steps are as follows:

[0053] (1) Prepare a clean transparent conductive substrate: ultrasonically clean an indium tin oxide (ITO) glass substrate with deionized water, acetone, and ethanol solvents for 15 minutes each in sequence to obtain a clean transparent conductive substrate;

[0054] (2) Prepare the electron transport layer: dilute a 15 wt% SnO2 dispersion with deionized water to 2.67 wt%, and ultrasonically disperse it for 30 minutes until the solution concentration is uniform. Then filter the obtained solution with a 0.22 μm aqueous filter head to prepare an electron transport layer solution. Use a pipette to aspirate 50 μL of the electron transport layer solution and drop it on the surface of the clean transparent conductive substrate. At this time, the rotation speed is 4000 rpm, the acceleration is 4000 rpm / s, and the rotation time is 30 s; after spin-coating, place it on a hot plate preheated to 150 °C and anneal for 30 minutes; after annealing, cool it to 25 °C to prepare the electron transport layer, perform ultraviolet cleaning for 15 minutes, and finally transfer it into an N2 glove box;

[0055] (3) Prepare the perovskite film: (a) Prepare the perovskite precursor pre-solution by dissolving CsI (14 mg), FAI (188 mg), MABr (22.7 mg), PbI2 (529.0 mg), and PbBr2 (74.5 mg) in 1 mL of a mixed solvent of DMF and DMSO (the volume ratio of DMF and DMSO is 4:1) to obtain a perovskite component of Cs 0.04 FA 0.81 MA 0.15 PbI 2.55 Br 0.45, a perovskite precursor pre-solution with a lead ion concentration of 1.35 mol / L; (b) Add 5 μL of TEOS to each milliliter of the perovskite precursor pre-solution, oscillate for 2 h, and then filter with a 0.45-μm polytetrafluoroethylene filter head to obtain the perovskite precursor solution; (c) Prepare the perovskite thin film: Take 100 μL of the perovskite precursor solution and drop it on the surface of the electron transport layer, rotate at a speed of 4000 rpm and an acceleration of 4000 rpm / s for 40 s, and add the anti-solvent chlorobenzene at the 25th second. After spin-coating, immediately anneal at 120 °C for 20 min to obtain a perovskite thin film with a thickness of 550 nm;

[0056] (4) Prepare the hole transport layer: Weigh 72.3 mg of 2,2",7,7"-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (spiro-OMeTAD) powder and dissolve it in 1 mL of chlorobenzene solution. After stirring at 25 °C for 3 h, add 17.5 μL of the lithium salt solution (the lithium salt solution is prepared by dissolving 520 mg of lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) in 1 mL of acetonitrile), 17.5 μL of the cobalt salt solution (the cobalt salt solution is prepared by dissolving 300 mg of tris(2-(1H-pyrazol-1-yl)-4-tert-butylpyridine)cobalt(III) tris[bis(trifluoromethane)sulfonylimide] (FK-209) in 1 mL of acetonitrile) and 27.5 μL of tetratert-butylpyridine, and continue to stir until completely dissolved. Filter with a 0.45-μm nylon filter head to obtain the hole transport layer solution; Use a pipette to take 40 μL of the hole transport layer solution and drop-coat it on the perovskite thin film, and rotate at a speed of 3500 rpm for 30 s to obtain the hole transport layer, and then expose the 2-mm ITO electrode with a utility knife;

[0057] (5) Prepare the metal electrode: Put the device prepared in step (4) into the chamber of a vacuum evaporation machine, and then pump the vacuum in the chamber to below 4×10 -4 Pa, and deposit silver with a thickness of 100 nm at an evaporation rate of to obtain the metal electrode and at the same time obtain a formal single-junction perovskite solar cell with an active area of 0.034 cm 2 .

[0058] Example 2

[0059] Other conditions in this example are the same as those in Example 1, except that in this example, 10 μL of TEOS is added to each milliliter of the perovskite precursor pre-solution.

[0060] Example 3

[0061] Other conditions in this example are the same as those in Example 1, except that in this example, 15 μL of TEOS is added to each milliliter of the perovskite precursor pre-solution.

[0062] Example 4

[0063] Other conditions in this example are the same as those in Example 1, except that 20 μL of TEOS is added to each milliliter of the perovskite precursor solution in this example.

[0064] Example 5

[0065] The preparation in this example Figure 1 The inverted single-junction perovskite solar cell shown in (b) is prepared as follows:

[0066] (1) Prepare a clean transparent conductive substrate: ultrasonically clean the ITO glass substrate with deionized water, acetone, and ethanol solvents for 15 min in sequence to obtain a clean transparent conductive substrate;

[0067] (2) Prepare a hole transport layer: Weigh 30 mg of NiOx nanoscale powder and disperse it in 1 mL of deionized water to obtain a NiOx nano-dispersion with a concentration of 30 mg / mL; use a pipette to aspirate 50 μL of the NiOx nano-dispersion and drop it on the surface of the clean transparent conductive substrate. At this time, the rotation speed is 4000 rpm, the acceleration is 4000 rpm / s, and the rotation time is 30 s; after spin-coating, place it on a hot plate preheated to 150 °C and anneal for 30 min to obtain a hole transport layer;

[0068] (3) Prepare a perovskite film: (a) Prepare a perovskite precursor solution by dissolving CsI (14 mg), FAI (188 mg), MABr (22.7 mg), PbI2 (529.0 mg), and PbBr2 (74.5 mg) in 1 mL of a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO is 4:1) to obtain a perovskite precursor solution with a perovskite composition of Cs 0.04 FA 0.81 MA 0.15 PbI 2.55 Br 0.45 and a lead ion concentration of 1.35 mol / L; (b) Add 5 μL of TEOS to each milliliter of the perovskite precursor solution, oscillate for 2 h, and then filter it with a 0.45 μm polytetrafluoroethylene filter head to obtain a perovskite precursor solution; (c) Prepare a perovskite film: Take 100 μL of the perovskite precursor solution and drop it on the surface of the electron transport layer, rotate at a rotation speed of 4000 rpm and an acceleration of 4000 rpm / s for 40 s, and add the anti-solvent chlorobenzene at the 25th second. After spin-coating, immediately anneal at 120 °C for 20 min to obtain a perovskite film with a thickness of 550 nm;

[0069] (4) Preparation of the electron transport layer: Dissolve 20 mg of [6,6]-phenyl-C61-butyric acid isopropyl ester (PCBM) powder in 1 mL of isopropanol. After oscillating and dissolving, a PCBM solution with a concentration of 20 mg / mL is obtained. Use a pipette to take 40 μL of the PCBM solution and drop it onto the perovskite film. Spin at 1500 rpm for 25 s, and then anneal on a heating table at 90 °C for 10 min to obtain the electron transport layer;

[0070] (5) Preparation of the hole blocking layer: Dissolve 0.5 mg of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) powder in 1 mL of isopropanol. After oscillating and dissolving, a BCP solution with a concentration of 0.5 mg / mL is obtained. Use a pipette to take 40 μL of the BCP solution and drip it onto the electron transport layer. Spin at 5000 rpm for 25 s, and then use a craft knife to expose a 2-mm ITO electrode;

[0071] (5) Preparation of the metal electrode: Place the device prepared in step (4) into the chamber of a vacuum evaporation machine. Then, evacuate the chamber to a vacuum below 4×10 -4 Pa, and deposit silver with an evaporation rate of to a thickness of 100 nm to obtain the metal electrode and a reverse single-junction perovskite solar cell with an effective area of 0.034 cm 2 .

[0072] Example 6

[0073] This example prepares Figure 2 the perovskite / silicon heterojunction solar cell as shown, and the specific steps are as follows:

[0074] (1) Preparation of the silicon bottom cell and the bottom electrode: Polish the N-type silicon wafer (c-Si), and the surface texture height is 500 - 1000 nm; Use PECVD to prepare the front intrinsic amorphous silicon (a-Si:H(i)) and n-type amorphous silicon (a-Si:H(n)) with a total thickness of 25 nm; Prepare the back intrinsic amorphous silicon (a-Si:H(i)) and p-type amorphous silicon (a-Si:H(p)) with a total thickness of 20 nm on the back; Use sputtering to prepare a bottom electrode with a thickness of 110 nm and a material of transparent conductive oxide ITO on the surface of the back p-type amorphous silicon (a-Si:H(n));

[0075] (2) Preparation of the tunneling layer: Use sputtering to prepare a tunneling layer with a thickness of 50 nm and a material of transparent conductive oxide ITO on the surface of the front n-type amorphous silicon (a-Si:H(n));

[0076] (3) Preparation of the hole transport layer: Use sputtering to prepare a hole transport layer with a thickness of 15 nm and a material of NiOx;

[0077] (4) Preparation of perovskite thin film: (a) Prepare the precursor solution of perovskite. Dissolve CsI (22.1 mg), MABr (28.5 mg), FAI (233.9 mg), PbI2 (548.6 mg), and PbBr2 (187.1 mg) in 1 mL of a mixed solvent of DMF and DMSO (the volume ratio of DMF to DMSO is 4:1) to obtain a perovskite precursor solution with a perovskite composition of Cs 0.05 MA 0.15 FA 0.8 Pb(I 0.75 Br 0.25 )3 and a lead ion concentration of 1.70 mol / L; (b) Add 10 μL of TEOS to each milliliter of the perovskite precursor solution, oscillate for 2 h, and then filter with a 0.45 μm polytetrafluoroethylene filter head to obtain the perovskite precursor solution; (c) Prepare the perovskite thin film: Take 100 μL of the perovskite precursor solution and drop it onto the surface of the electron transport layer. Spin at a speed of 2000 rpm and an acceleration of 2000 rpm / s for 40 s, and then spin at a speed of 6000 rpm and an acceleration of 6000 rpm / s for 20 s. Drop the antisolvent anisole at the 40 s of the total time. Immediately anneal at 100 °C for 20 min after spin coating to obtain a perovskite thin film with a thickness of 900 nm;

[0078] (5) Preparation of the passivation layer: Use thermal evaporation to prepare a passivation layer with a material of LiF and a thickness of 1 nm on the surface of the perovskite thin film;

[0079] (6) Preparation of the electron transport layer: Use thermal evaporation to prepare an electron transport layer with a material of C60 and a thickness of 12 nm on the surface of the passivation layer;

[0080] (7) Preparation of the hole blocking layer: Use atomic deposition to prepare a hole blocking layer with a material of SnO2 and a thickness of 15 nm on the surface of the electron transport layer;

[0081] (8) Preparation of the top electrode: Use evaporation to prepare a transparent conductive electrode with a material of ITO and a thickness of 40 nm on the surface of the hole blocking layer; Use thermal evaporation to deposit a metal electrode with a material of Ag and a thickness of 200 nm on the surface of the transparent conductive electrode; The transparent conductive electrode and the metal electrode form the top electrode.

[0082] Comparative Example 1

[0083] Other conditions of this comparative example are the same as those of Example 1, except that TEOS is not added to the perovskite precursor solution in this comparative example.

[0084] Comparative Example 2:

[0085] Other conditions of this comparative example are the same as those of Example 5, except that TEOS is not added to the perovskite precursor solution of this comparative example.

[0086] Comparative Example 3

[0087] Other conditions of this comparative example are the same as those of Example 6, except that TEOS is not added to the perovskite precursor solution of this comparative example.

[0088] Test Example 1

[0089] Performance test of perovskite solar cells: At 25 °C and under the standard solar spectrum of AM 1.5G, using a solar simulator, the voltage range was set to 1.3 - 0.2 V, and the current output of the perovskite solar cells prepared in Examples 1 - 6 and Comparative Examples 1 - 3 at different voltages was tested, and the corresponding current-voltage (I-V) characteristic curves were plotted. Among them, the incident light power (Pin) was 100 mW / cm 2 . The performance (open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency) of the perovskite solar cells prepared in Examples 1 - 6 and Comparative Examples 1 - 3 was obtained according to the characteristic curves.

[0090] (1) Open-circuit voltage (Voc): The voltage value corresponding to when the current is zero.

[0091] (2) Short-circuit current density (Jsc): The current value when the voltage is zero is the short-circuit current (Isc), and the current magnitude per unit cell surface area is the short-circuit current density.

[0092] (3) Fill factor (FF): The ratio of the maximum output power (Pmax) of the cell to the product of the open-circuit voltage and the short-circuit current, and the calculation formula is (Pmax / Voc*Isc), where the maximum power point is the point where the cell output power reaches the maximum value.

[0093] (4) Photoelectric conversion efficiency (PCE): The photoelectric conversion efficiency refers to the ratio of the maximum output power to the incident light power (Pin), and the calculation formula is (Pmax / Pin)*100%.

[0094] 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 - 6 and Comparative Examples 1 - 3 are shown in Table 1.

[0095] Table 1: Open-circuit voltage, short-circuit current density, fill factor, and photoelectric conversion efficiency of the perovskite solar cells prepared in Examples 1 - 6 and Comparative Examples 1 - 3

[0096] <![CDATA[V OC (V)]]> <![CDATA[J SC (mA / cm 2 )]]> FF (%) PCE (%) Example 1 1.16 25.87 82.89 24.87 Example 2 1.16 25.74 83.01 24.78 Example 3 1.17 25.72 82.97 24.96 Example 4 1.17 25.68 82.92 24.91 Example 5 1.17 25.82 80.34 24.27 Example 6 2.00 20.37 82.89 33.76 Comparative Example 1 1.12 25.66 77.06 22.12 Comparative Example 2 1.14 25.50 78.77 22.89 Comparative Example 3 1.98 20.21 79.94 31.98

[0097] Test Example 2

[0098] Stability Test of Perovskite Solar Cells: The unencapsulated devices were stored in an environment of 28 °C and 45% relative humidity. The above J-V scans were performed daily for 30 days, and the normalized PCE-T curves were recorded. The normalized PCE-T curves of the perovskite solar cells prepared in Example 4 and Comparative Example 1 are as Figure 3 shown. The normalized PCE-T curves of the perovskite solar cells prepared in Example 5 and Comparative Example 2 are as Figure 4 shown. The normalized PCE-T curves of the perovskite solar cells prepared in Example 6 and Comparative Example 3 are as Figure 5 shown. Figure 3 、 Figure 4 and Figure 5 The optoelectronic parameters of Examples 4-6 and Comparative Examples 1-3 at different control times are shown in Table 2.

[0099] Table 2: Optoelectronic Parameters of Perovskite Solar Cells Prepared in Examples 4-6 and Comparative Examples 1-3 at Different Control Times

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Claims

1. A method for preparing a perovskite precursor solution, characterized in that, The method includes mixing a perovskite-structured material raw material and a solvent, then adding tetraethyl orthosilicate and mixing, and filtering to obtain a perovskite precursor solution.

2. The method according to claim 1, wherein The method has one or more of the following characteristics: The perovskite-structured material raw material is AX and BX2. The A ion is selected from one or more of cesium ion, rubidium ion, methylammonium ion, and formamidinium ion; the B ion is lead ion and / or tin ion; the X ion is selected from one or more of iodide ion, bromide ion, and chloride ion; The solvent is selected from one or more of N,N-dimethylformamide, dimethyl sulfoxide, and N-methylpyrrolidone; The addition amount of tetraethyl orthosilicate in the perovskite precursor solution is 5-20 μL / mL of the solvent; In the perovskite precursor solution, the concentration of the B ion is 1.0-1.6 mol / L.

3. The method according to claim 2, wherein The A ion is selected from one or more of cesium ion, methylammonium ion, and formamidinium ion; the B ion is lead ion; the X ion is iodide ion and / or bromide ion.

4. A perovskite precursor solution prepared by the method according to any one of claims 1-3.

5. A method for preparing a perovskite thin film, characterized in that, The method includes: coating the perovskite precursor solution according to claim 4, and annealing to obtain a perovskite thin film.

6. The method according to claim 5, wherein The method has one or more of the following characteristics: The coating method of the perovskite precursor solution is spin coating or blade coating; The annealing temperature is 100-120 °C; The annealing time is 20-30 min.

7. A perovskite thin film prepared by the method according to claim 5 or 6.

8. The perovskite thin film according to claim 7, wherein The thickness of the perovskite thin film is 400-1200 nm; and / or The perovskite thin film contains a perovskite-structured material, and the chemical formula of the perovskite-structured material is ABX3. The A ion is selected from one or more of cesium ion, rubidium ion, methylammonium ion, and formamidinium ion; the B ion is lead ion and / or tin ion; the X ion is selected from one or more of iodide ion, bromide ion, and chloride ion.

9. The perovskite thin film according to claim 7, wherein, The perovskite-structured material is FA a MA b Cs c Pb(I m Br n )3, a + b + c = 1, m + n = 1, 0 < c < 0.3, 0 < a < 1, 0 < b < 1; preferably, a:(b + c) = 1:(0 - 0.25).

10. A perovskite solar cell comprising the perovskite thin film according to any one of claims 7-9.

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