A perovskite solar cell based on additive-assisted preparation of high-quality photoactive layer

Abstract

The present invention discloses a perovskite solar cell with an additive-assisted high-quality photoactive layer. The perovskite solar cell consists of, from bottom to top, a substrate, an electron transport layer, an organic-inorganic perovskite structure photoactive layer, a hole transport layer, and a back electrode layer. The organic-inorganic perovskite structure photoactive layer is prepared by doping a fluorine-containing additive with a lead iodide film, which is then reacted on the lead iodide film to prepare a perovskite film. The fluorine-containing additive doping volume fraction is 1% to 25%. The present invention improves the film quality of the perovskite layer by introducing a fluorine-containing additive, thereby improving the photoelectric efficiency, environmental stability, and other properties of the perovskite solar cell.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a perovskite solar cell based on additive-assisted preparation of a high-quality photoactive layer. Background Art

[0002] Perovskite solar cells have experienced rapid development in recent years due to their excellent photovoltaic performance, reaching a maximum efficiency exceeding 26% by 2023. Perovskite materials have gradually become the most promising option for solar energy systems due to their superior light absorption coefficient, low cost, ease of fabrication, and low-light performance. The morphology and quality of perovskite films significantly impact the device's photovoltaic performance, making the preparation of high-quality perovskite films a key research focus. Currently, popular methods for producing perovskite films include vapor deposition, spray coating, and spin coating (either one-step or two-step). The two-step spin coating method offers greater opportunities to influence the crystallization of the perovskite layer and has become a typical and widely adopted laboratory method.

[0003] Typically, a PbI2 thin film is first prepared using a mixed solution containing lead iodide (PbI2) with N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). A monovalent halide solution, such as formamidine iodide (FAI), is then spin-coated onto the PbI2 thin film to convert it into a perovskite phase. However, the PbI2 thin film prepared by the conventional two-step spin-coating method is too smooth, which is not conducive to the penetration and reaction of the monovalent halide solution, resulting in a large amount of PbI2 residue and a disappointing microstructure of the perovskite film. Low-quality perovskite films have low crystallinity, irregular surface morphology, poor reproducibility, and high levels of grain boundary or interface defects, which are the primary pathways for ion migration. Ion movement causes hysteresis and phase separation in the photovoltage-current curve of the perovskite active layer. The low-quality perovskite film and the large amount of PbI2 residue also accelerate the corrosion of the perovskite film by water and oxygen, reducing the performance and stability of the device. Summary of the Invention

[0004] The purpose of the present invention is to provide a perovskite solar cell with a high-quality photoactive layer prepared with the assistance of additives. The present invention improves the film quality of the perovskite layer by introducing fluorine-containing additives, thereby improving the photoelectric efficiency, environmental stability and other properties of the perovskite solar cell.

[0005] The present invention is achieved through the following technical solutions:

[0006] A perovskite solar cell with an additive-assisted high-quality photoactive layer is composed, from bottom to top, of a substrate, an electron transport layer, an organic-inorganic perovskite structure photoactive layer, a hole transport layer, and a back electrode layer. The organic-inorganic perovskite structure photoactive layer is prepared by doping a fluorine-containing additive with the aid of a lead iodide film, and then reacting the lead iodide film to prepare a perovskite film. The fluorine-containing additive doping volume fraction is 1% to 25%.

[0007] Preferably, the organic-inorganic perovskite structured photoactive layer is prepared by a two-step spin coating or doctor blade coating method, i.e., first preparing a lead iodide film and then chemically reacting to form the perovskite film. The fluorine-containing additive is used to modify the morphology of the lead iodide film in the first step and does not remain in the lead iodide film after preparation.

[0008] Preferably, the fluorine-containing additive is a fluorine-containing aromatic hydrocarbon or a fluorine-containing alkane with a boiling point below 100°C.

[0009] More preferably, the fluorinated aromatic hydrocarbon is hexafluorobenzene or octafluoronaphthalene, and the fluorinated alkane is perfluoropentane, perfluorohexane or perfluoroheptane.

[0010] The present invention also protects the above-mentioned method for preparing a perovskite solar cell with a high-quality photoactive layer assisted by additives, comprising the following steps:

[0011] S1, cleaning the substrate;

[0012] S2. preparing an electron transport layer on a transparent substrate by a solution method;

[0013] S3. Uniformly coating a fluorine-containing lead iodide precursor solution on the electron transport layer obtained in step S2 to obtain a lead iodide thin film, wherein the fluorine-containing lead iodide precursor solution is prepared according to the following steps: adding a fluorine-containing additive to a lead iodide precursor solution having a molar concentration of 1.2 to 1.5 mmol / mL to obtain a fluorine-containing lead iodide precursor solution having a volume fraction of the fluorine-containing additive of 1% to 25%;

[0014] S4. Uniformly coating a monovalent halide solution having a molar concentration of 1.2 to 1.5 mmol / mL on the lead iodide film obtained in step S3 to obtain a perovskite film, i.e., an organic-inorganic perovskite structure photoactive layer;

[0015] S5. A hole transport layer and a back electrode layer are sequentially prepared on the perovskite film obtained in step S4, and finally the perovskite solar cell is obtained.

[0016] Preferably, the coating method in step S3 or S4 is a blade coating method or a spin coating method. The organic-inorganic perovskite structure photoactive layer is prepared by a two-step spin coating method or a two-step blade coating method.

[0017] The electron transport layer described in step S2 is a tin dioxide electron transport layer, which is prepared by the following steps: the SnO2 precursor solution is evenly dropped on the transparent substrate, and the spin coating is performed at a spin coating speed of 3500 to 4500 r / min for 15 to 25 seconds. After the spin coating is completed, the sheet is removed from the spin coater and annealed on a constant temperature heating table at 140°C to 160°C for 25 to 35 minutes to obtain a SnO2ETL film (i.e., a tin dioxide electron transport layer).

[0018] Further preferably, the specific steps of steps S3 and S4 are:

[0019] S3. Spin-coating a fluorine-containing lead iodide precursor solution on the tin dioxide electron transport layer obtained in step S2 at a rotation speed of 1500 to 2000 rpm for 20 to 40 seconds. After the spin coating is completed, thermal annealing is performed at less than 80° C. for 10 to 80 seconds to obtain a lead iodide thin film.

[0020] S4. Spin-coat a monovalent halide solution on the lead iodide film obtained in step S3 at a rotation speed of 1500-2000 rpm for 20-40 seconds. After the spin coating is completed, anneal the film at 140° C.-160° C. for 10-20 minutes in an atmosphere with a humidity of 30%-45% to obtain a perovskite film.

[0021] Further preferably, the specific steps of steps S3 and S4 are:

[0022] S3. Scraping the lead iodide thin film on the tin dioxide electron transport layer obtained in step S2 at a scraping speed of 80 to 120 mm / min, a transparent substrate heating temperature of less than 80° C., and a gap between the scraper and the substrate surface of 90 to 110 μm.

[0023] S4. On the lead iodide film obtained in step S3, a monovalent halide solution is scraped at a scraping speed of 80 to 120 mm / min. The substrate is not heated, and the gap between the scraper and the substrate surface is 90 to 110 μm. The wet film obtained by scraping is annealed at 140° C. to 160° C. for 10 to 20 minutes in an atmospheric environment with a humidity of 30% to 45% to obtain a perovskite film.

[0024] Preferably, the volume fraction of the fluorine-containing additive is 5% to 20%, and more preferably, the volume fraction of the fluorine-containing additive is 10% to 20%.

[0025] Preferably, the monovalent halide in step S4 has the general formula AX, where A is a +1 cation and includes FA + 、MA + 、Cs + , Rb + , X is a halide ion, including Cl - Br - 、I-.

[0026] Preferably, the substrate in step S1 is fluorine-doped tin oxide transparent conductive glass (FTO) or indium tin oxide transparent conductive film glass (ITO) or indium tin oxide transparent polyethylene naphthalate film (PEN-ITO) or indium tin oxide transparent polyethylene terephthalate film (PET-ITO).

[0027] Preferably, the thickness of the electron transport layer is 20-40 nm, the thickness of the organic-inorganic perovskite structure photoactive layer is 580-620 nm, the thickness of the hole transport layer is 100-200 nm, and the thickness of the back electrode layer is 50-100 nm. The hole transport layer is a 2,2',7,7'-tetrakis-N,N-bis(4-methoxyphenyl)amino-9,9'-spirobifluorene (Spiro-OMeTAD) layer. The back electrode layer is a metal electrode layer, and the metal electrode is a gold electrode.

[0028] The preparation steps of the hole transport layer are as follows: spreading the hole transport layer precursor solution on a substrate provided with an organic-inorganic perovskite structure photoactive layer, and then spin coating at a spin coating speed of 3500-4500 r / min for 20-40s to obtain the hole transport layer.

[0029] The back electrode is prepared by vacuum coating method.

[0030] Compared with the prior art, the present invention has the following beneficial effects: the present invention introduces a green and environmentally friendly additive hexafluorobenzene (HFB) into the first step of the lead iodide precursor solution in the preparation of the perovskite film by a two-step spin coating or blade coating method, thereby obtaining a lead iodide film morphology that is different from the smooth first step of the traditional two-step method. The lead iodide film morphology after the introduction of hexafluorobenzene becomes rough and porous, which is conducive to the second step of the organic solution penetration and intercalation reaction, thereby obtaining a high-quality perovskite film with increased grain size, improved surface morphology, and reduced defect state density, thereby improving the photoelectric efficiency, environmental stability and other performance of the perovskite solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Schematic diagram of the structure of the perovskite solar cell prepared in the present invention;

[0032] Figure 2 This is a JV curve diagram of the perovskite solar cell prepared in Example 1 of the present invention;

[0033] Figure 3 This is a JV curve diagram of the perovskite solar cell prepared in Example 2 of the present invention.

[0034] Figure 4This is a storage stability test chart of the perovskite solar cells prepared in Example 1 of the present invention and Comparative Example 1 under the protocol test ID: ISOS-D-lshelf that meets the International Organic Photovoltaic Stability Summit. DETAILED DESCRIPTION

[0035] The present invention will be described in further detail below with reference to the examples. These examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. Experimental methods in the following examples, where specific conditions are not specified, generally follow conventional conditions in the art or conditions recommended by the manufacturer; raw materials and reagents used, unless otherwise specified, are considered to be commercially available through conventional markets.

[0036] like Figure 1 As shown, a perovskite solar cell based on additive-assisted preparation of a high-quality photoactive layer is composed of a substrate, an electron transport layer (tin dioxide), an organic-inorganic perovskite structure photoactive layer (Perovskite), a hole transport layer, and a back electrode layer from bottom to top. In the following embodiment, the substrate is preferably a fluorine-doped tin oxide transparent conductive glass (FTO), the electron transport layer is a tin dioxide (SnO2) electron transport layer (SnO2 ETL layer), the hole transport layer is a 2,2',7,7'-tetrakis N,N-bis(4-methoxyphenyl)amino-9,9'-spirobifluorene (Spiro-OMeTAD) layer (HTL layer), and the back electrode layer is a metal electrode layer, and the metal electrode is a gold electrode.

[0037] In the following Examples 1 and 2, the precursor solution is prepared by the following steps:

[0038] Preparation of SnO2 ETL layer precursor solution: Use 15wt% SnO2 nanocrystal aqueous colloidal dispersion (particle size 3-5nm) commercially available from Alfa Asear, dilute to 3.75wt% (1:3) by adding deionized water, and filter to obtain SnO2 precursor solution for use;

[0039] Preparation of PbI2 precursor solution: Prepare a lead iodide precursor solution with a molar concentration of 1.3 mmol / mL, heat and stir on a constant temperature heating table until completely dissolved, add hexafluorobenzene as a fluorine-containing additive, and keep it in a heated state to obtain a fluorine-containing lead iodide precursor solution with a fluorine-containing additive volume ratio of 15%;

[0040] Preparation of FAMA precursor solution: Based on the preparation of 1.5 mL of precursor solution, 90 mg of FAI, 9 mg of MACl, and 9 mg of MABr were accurately weighed using an analytical balance in a glove box and added to a clean brown empty bottle. 1.5 mL of IPA solvent was then added and stirred for 30 min until the solute was completely dissolved. Filtered with a polytetrafluoroethylene filter (0.22 μm) before spin coating;

[0041] Preparation of Spiro-OMeTAD HTL layer precursor solution: Based on the preparation of 1 mL of Spiro solution, 72.3 mg of Spiro-OMeTAD powder was accurately weighed using an analytical balance in a nitrogen glove box. 1 mL of chlorobenzene, 28.8 μL of TBP, 17.5 μL of a 520 mg / mL lithium salt acetonitrile solution, and 20 μL of a 300 mg / mL Co salt (FK209) acetonitrile solution were added in sequence. The mixture was mixed in a brown light-proof bottle, and after complete dissolution, it was filtered using a polytetrafluoroethylene filter (0.22 μm) for later use.

[0042] Example 1

[0043] A method for preparing a perovskite solar cell with an additive-assisted high-quality photoactive layer, wherein the photoactive layer is prepared by a two-step spin coating method, specifically comprising the following steps:

[0044] S1. Rigid substrate cleaning: Place the FTO substrate on a custom cleaning rack and clean the FTO conductive glass with FTO cleaning solution (FTO cleaning agent: deionized water = 1:20), deionized water (DI), anhydrous ethanol, and isopropyl alcohol in sequence to remove adhesives and residual cleaning agent on the substrate surface. Each round of cleaning requires the glass to be ultrasonically cleaned in an ultrasonic cleaner for 15 minutes. After the last round of isopropyl alcohol cleaning, use a nitrogen blow gun to blow dry the isopropyl alcohol on the surface of the FTO conductive glass, and then place the substrate in a clean culture dish for later use.

[0045] S2. Preparation of SnO2 ETL layer: The FTO conductive glass cleaned in step S1 was sent to the UV-O3 machine for ultraviolet treatment for 20 minutes. After the wafer was cooled to room temperature, it was placed on the spin coater suction cup and the surface was blown with an ear bulb. Then, 100 μL of the prepared SnO2 precursor solution was drawn with a 100 μL pipette and evenly dropped on the substrate. The spin coating was carried out at a speed of 4000 r / min for 20 seconds. After the spin coating was completed, the wafer was removed from the spin coater and annealed at 150°C on a constant temperature heating table for 30 minutes to obtain a SnO2 ETL film with a thickness of 30 nm.

[0046] S3. Preparation of lead iodide film: On the substrate that had been spin-coated with SnO2 ETL film, a fluorine-containing lead iodide precursor solution was spin-coated at a speed of 1700 rpm for 30 seconds. After spin coating, the solution was thermally annealed on a 70°C constant temperature heating table for 10 seconds to obtain a lead iodide film with a thickness of 580 nm.

[0047] S4. Preparation of FAMACs perovskite film: Place the substrate with the PbI2 film spin-coated in S3 on the spin coater chuck, blow air on the surface with an ear bulb, and use dynamic spin coating. When the substrate is rotating at a constant speed of 1700 r / min, spin-coat 70 mL of FAMA precursor solution for 30 seconds. After the spin coating is completed, immediately transfer the substrate from the glove to an atmosphere at room temperature (25±2)°C and 40% humidity, anneal at 150°C for 15 minutes to obtain a FAMACs perovskite film with a thickness of 600 nm.

[0048] S5. Preparation of HTL layer: After cooling the substrate to room temperature, place it on the spin coater chuck and blow air on the surface with an ear bulb. Then, use a 100 μL pipette to draw 50 μL of filtered Spiro-OMeTAD precursor solution and evenly drop it on the substrate. After the Spiro solution spreads over the entire substrate, spin coat at a speed of 4000 rpm for 30 seconds to obtain a 150 nm thick HTL layer.

[0049] S6. Transfer the substrate with the HTL layer spin-coated from the glove box to a room with a temperature of (25±2)℃ and a humidity of 40%. Use a surgical blade to scrape a 3-4mm gap parallel to the edge of the wafer. Transfer the substrate to the vacuum coating evaporation chamber of the glove box. Use the evaporation chamber to coat the substrate with HTL layer. Evaporation rate, 1~5nm using Evaporation rate, 5~10nm use Evaporation rate, 10~80nm The evaporation rate was 0.80 nm to obtain a gold electrode with a thickness of 80 nm. After the evaporation was completed, the device was transferred to a dry air box with a humidity of 5% to 10% to avoid light oxidation for 12 hours. The final device efficiency was 23.01%. The JV curve is shown in Figure 2 shown.

[0050] Example 2

[0051] A method for preparing a perovskite solar cell with a high-quality photoactive layer assisted by an additive, wherein the photoactive layer is coated using a two-step doctor blade method, specifically comprising the following steps:

[0052] S1. Rigid substrate cleaning: Place the FTO substrate on a custom cleaning rack and clean the FTO conductive glass with FTO cleaning solution (FTO cleaning agent: deionized water = 1:20), deionized water (DI), anhydrous ethanol, and isopropyl alcohol in sequence to remove adhesives and residual cleaning agent on the substrate surface. Each round of cleaning requires the glass to be ultrasonically cleaned in an ultrasonic cleaner for 15 minutes. After the last round of isopropyl alcohol cleaning, use a nitrogen blow gun to blow dry the isopropyl alcohol on the surface of the FTO conductive glass, and then place the substrate in a clean culture dish for later use.

[0053] S2. Preparation of SnO2 ETL layer: The FTO conductive glass cleaned in step S1 was sent to the UV-O3 machine for ultraviolet treatment for 20 minutes. After the substrate was cooled to room temperature, it was placed on the spin coater suction cup and the surface was blown with an ear bulb. Then, 100 μL of the prepared SnO2 precursor solution was taken with a 100 μL pipette and evenly dropped on the substrate. The spin coating was carried out at a speed of 4000 r / min for 20 seconds. After the spin coating was completed, the wafer was removed from the spin coater and annealed at 150°C on a constant temperature heating table for 30 minutes to obtain a SnO2 ETL film with a thickness of 30 nm.

[0054] S3. Preparation of lead iodide thin film: On a substrate that has been spin-coated with SnO2 ETL film, a fluorine-containing lead iodide precursor solution is added dropwise into the gap at a speed of 100 mm / min, the substrate is heated to 70°C, and the gap between the scraper and the substrate surface is 100 μm. A lead iodide film with a thickness of 580 nm is obtained by scraping.

[0055] S4. Preparation of FAMACs perovskite film: On the lead iodide film obtained in step S3, a doctor blade was applied at a speed of 100 mm / min, the substrate was not heated, and a gap of 100 μm between the doctor blade and the substrate surface was maintained. The wet film obtained by doctor blade application was annealed at 150° C. for 15 min in an atmosphere with a humidity of 30% to 45%, to obtain a perovskite film with a thickness of 600 nm.

[0056] S5. Preparation of HTL layer: After cooling the substrate to room temperature, place it on the spin coater chuck and blow air on the surface with an ear bulb. Then, use a 100 μL pipette to draw 50 μL of filtered Spiro-OMeTAD precursor solution and evenly drop it on the substrate. After the Spiro solution spreads over the entire substrate, spin coat at a speed of 4000 rpm for 30 seconds to obtain a 150 nm thick HTL layer.

[0057] S6. Transfer the substrate with the HTL layer spin-coated from the glove box to a room with a temperature of (25±2)℃ and a humidity of 40%. Use a surgical blade to scrape a 3-4mm gap along the edge of the wafer parallel to the edge. Transfer the wafer to the vacuum coating evaporation chamber of the glove box. Use the evaporation chamber to coat the wafer with HTL layer. Evaporation rate, 1~5nm using Evaporation rate, 5~10nm use Evaporation rate, 10~80nm The evaporation rate was set to obtain a gold electrode with a thickness of 80 nm. After the evaporation was completed, the device was transferred to a dry air box with a humidity of 5% to 10% to avoid light oxidation for 12 hours. The final device efficiency was 21.23%. The JV curve is shown in Figure 3 shown.

[0058] Comparative Example 1

[0059] In this comparative example, a perovskite solar cell was prepared according to the steps of Example 1. Compared with Example 1, the only difference was that no fluorine-containing additive was added to the lead iodide precursor solution in step S3. The efficiency of the device finally prepared was 20.95%.

[0060] The stability comparison test of Example 1 and Comparative Example 1 is as follows Figure 4 As shown in FIG1 , after adding the fluorine-containing additive in Example 1, the storage stability of the perovskite solar cell is significantly improved.

[0061] Comparative Example 2

[0062] In this comparative example, a perovskite solar cell was prepared according to the steps of Example 2. The only difference from Example 2 was that no fluorine-containing additive was added to the lead iodide precursor solution in step S3. The efficiency of the device finally prepared was 19.16%.

[0063] Example 3

[0064] In this embodiment, a perovskite solar cell was prepared according to the steps of Example 1. The only difference from Example 1 was that the fluorine-containing additive added to the lead iodide precursor solution in step S3 was replaced by octafluoronaphthalene instead of hexafluorobenzene. The final device efficiency was 22.34%.

[0065] Example 4

[0066] In this embodiment, a perovskite solar cell was prepared according to the steps of Example 2. The only difference from Example 2 was that the fluorine-containing additive added to the lead iodide precursor solution in step S3 was replaced by octafluoronaphthalene instead of hexafluorobenzene. The final device efficiency was 20.27%.

[0067] Example 5

[0068] In this embodiment, a perovskite solar cell was prepared according to the steps of Example 1. The only difference from Example 1 was that the fluorine-containing additive added to the lead iodide precursor solution in step S3 was replaced by perfluoropentane instead of hexafluorobenzene. The final device efficiency was 22.56%.

[0069] Example 6

[0070] In this embodiment, a perovskite solar cell was prepared according to the steps of Example 2. The only difference from Example 2 was that the fluorine-containing additive added to the lead iodide precursor solution in step S3 was replaced by perfluoropentane instead of hexafluorobenzene. The final device efficiency was 20.65%.

[0071] Example 7

[0072] In this example, a perovskite solar cell was prepared according to the steps of Example 1. The only difference from Example 1 was that the fluorine-containing additive added to the lead iodide precursor solution in step S3 was replaced by perfluorohexane instead of hexafluorobenzene. The final device efficiency was 21.87%.

[0073] Example 8

[0074] In this embodiment, a perovskite solar cell was prepared according to the steps of Example 2. The only difference from Example 2 was that the fluorine-containing additive added to the lead iodide precursor solution in step S3 was replaced by perfluorohexane instead of hexafluorobenzene. The final device efficiency was 19.95%.

[0075] Example 9

[0076] In this embodiment, a perovskite solar cell was prepared according to the steps of Example 1. The only difference from Example 1 was that the fluorine-containing additive added to the lead iodide precursor solution in step S3 was replaced by perfluoroheptane instead of hexafluorobenzene. The final device efficiency was 21.56%.

[0077] Example 10

[0078] In this embodiment, a perovskite solar cell was prepared according to the steps of Example 2. The only difference from Example 2 was that the fluorine-containing additive added to the lead iodide precursor solution in step S3 was replaced by perfluoroheptane instead of hexafluorobenzene. The final device efficiency was 19.67%.

[0079] Table 1 shows a comparison of device efficiencies obtained using different fluorine-containing additives in Examples 1-10 and Comparative Examples 1-2.

[0080] Table 1

[0081]

[0082]

[0083] Example 11

[0084] Same as Example 1, except that:

[0085] S2. Spin coating at a speed of 3500 r / min for 25 seconds. After spin coating, remove the wafer from the spin coater and anneal it on a constant temperature heating table at 140°C for 35 minutes to obtain a SnO2 ETL film (i.e., tin dioxide electron transport layer) with a thickness of 20 nm.

[0086] S3. Spin-coating a fluorine-containing lead iodide precursor solution on the electron transport layer obtained in step S2 at a rotation speed of 1500 rpm for 40 seconds, and thermally annealing at 70° C. for 10 seconds after the spin coating is completed to obtain a lead iodide film with a thickness of 570 nm. The fluorine-containing lead iodide precursor solution is prepared by the following steps: preparing a lead iodide precursor solution with a molar concentration of 1.2 mmol / mL, heating and stirring on a constant temperature heating table until completely dissolved, adding hexafluorobenzene as a fluorine-containing additive, and maintaining the heated state to obtain a fluorine-containing lead iodide precursor solution with a volume fraction of the fluorine-containing additive of 10%;

[0087] S4. Spin-coating a monovalent halide solution on the lead iodide film obtained in step S3 at a rotation speed of 1500 rpm for 40 seconds. After the spin coating is completed, annealing is performed at 140° C. for 20 minutes in an atmosphere with a humidity of 30% to 45% to obtain a perovskite film with a thickness of 590 nm.

[0088] S5, spin coating at a speed of 3500 rpm for 40 seconds to obtain a hole transport layer with a thickness of 100 nm;

[0089] S6. Transfer the substrate with the HTL layer spin-coated from the glove box to a room with a temperature of (25±2)℃ and a humidity of 40%. Use a surgical blade to scrape a 3-4mm gap along the edge of the wafer parallel to the edge. Transfer the wafer to the vacuum coating evaporation chamber of the glove box. Use the evaporation chamber to coat the wafer with HTL layer. Evaporation rate, 1~5nm using Evaporation rate, 5~10nm use Evaporation rate, 10~50nm use The evaporation rate was 50 nm to obtain a gold electrode with a thickness of 50 nm.

[0090] Example 12

[0091] Same as Example 1, except that:

[0092] S2. Spin coating at a speed of 4500 r / min for 15 seconds. After spin coating, remove the wafer from the spin coater and anneal it on a constant temperature heating table at 160°C for 25 minutes to obtain a SnO2 ETL film (i.e., tin dioxide electron transport layer) with a thickness of 40 nm.

[0093] S3. Spin-coating a fluorine-containing lead iodide precursor solution on the electron transport layer obtained in step S2 at a rotation speed of 2000 rpm for 20 seconds, and thermally annealing at 50° C. for 80 seconds after the spin coating is completed to obtain a lead iodide film with a thickness of 590 nm. The fluorine-containing lead iodide precursor solution is prepared by the following steps: preparing a lead iodide precursor solution with a molar concentration of 1.5 mmol / mL, heating and stirring on a constant temperature heating table until completely dissolved, adding hexafluorobenzene as a fluorine-containing additive, and maintaining the heated state to obtain a fluorine-containing lead iodide precursor solution with a volume fraction of the fluorine-containing additive of 20%;

[0094] S4. Spin-coating a monovalent halide solution on the lead iodide film obtained in step S3 at a rotation speed of 2000 rpm for 20 seconds. After the spin coating is completed, annealing is performed at 160° C. for 10 minutes in an atmosphere with a humidity of 30% to 45% to obtain a perovskite film with a thickness of 610 nm.

[0095] S5, spin coating at a speed of 4500 rpm for 20 seconds to obtain a hole transport layer with a thickness of 200 nm;

[0096] S6. Transfer the substrate with the HTL layer spin-coated from the glove box to a room with a temperature of (25±2)℃ and a humidity of 40%. Use a surgical blade to scrape a 3-4mm gap along the edge of the wafer parallel to the edge. Transfer the wafer to the vacuum coating evaporation chamber of the glove box. Use the evaporation chamber to coat the wafer with HTL layer. Evaporation rate, 1~5nm using Evaporation rate, 5~10nm use Evaporation rate, 10~100nm The evaporation rate was 100 nm to obtain a gold electrode with a thickness of 100 nm.

[0097] Example 13

[0098] Same as Example 1, except that:

[0099] S2. Spin coating at a speed of 3500 r / min for 25 seconds. After spin coating, remove the wafer from the spin coater and anneal it on a constant temperature heating table at 140°C for 35 minutes to obtain a SnO2 ETL film (i.e., tin dioxide electron transport layer) with a thickness of 20 nm.

[0100] S3. On the electron transport layer obtained in step S2, on the substrate on which the SnO2 ETL film has been spin-coated, a fluorine-containing lead iodide precursor solution is dripped into the gap at a scraping speed of 80 mm / min, a substrate heating temperature of 70°C, and a gap of 90 μm between the scraper and the substrate surface, and scraping is performed to obtain a lead iodide film with a thickness of 570 nm. The fluorine-containing lead iodide precursor solution is prepared by the following steps: preparing a lead iodide precursor solution with a molar concentration of 1.2 mmol / mL, heating and stirring on a constant temperature heating table until completely dissolved, adding hexafluorobenzene as a fluorine-containing additive, and maintaining the heated state to obtain a fluorine-containing lead iodide precursor solution with a volume fraction of the fluorine-containing additive of 10%;

[0101] S4. On the lead iodide film obtained in step S3, a wet film obtained by scraping was annealed at 140° C. for 20 min in an atmosphere with a humidity of 30% to 45% at a speed of 80 mm / min, without heating the substrate, and with a gap of 90 μm between the scraper and the substrate surface, to obtain a perovskite film with a thickness of 590 nm.

[0102] S5, spin coating at a speed of 3500 rpm for 40 seconds to obtain a hole transport layer with a thickness of 100 nm;

[0103] S6. Transfer the substrate with the HTL layer spin-coated from the glove box to a room with a temperature of (25±2)℃ and a humidity of 40%. Use a surgical blade to scrape a 3-4mm gap along the edge of the wafer parallel to the edge. Transfer the wafer to the vacuum coating evaporation chamber of the glove box. Use the evaporation chamber to coat the wafer with HTL layer. Evaporation rate, 1~5nm using Evaporation rate, 5~10nm use Evaporation rate, 10~50nm use The evaporation rate was 50 nm to obtain a gold electrode with a thickness of 50 nm.

[0104] Example 14

[0105] Same as Example 1, except that:

[0106] S2. Spin coating at a speed of 4500 r / min for 15 seconds. After spin coating, remove the wafer from the spin coater and anneal it on a constant temperature heating table at 160°C for 25 minutes to obtain a SnO2 ETL film (i.e., tin dioxide electron transport layer) with a thickness of 40 nm.

[0107] S3. On the electron transport layer obtained in step S2, on the substrate on which the SnO2 ETL film has been spin-coated, a fluorine-containing lead iodide precursor solution is dropwise added into the gap at a scraping speed of 120 mm / min, a substrate heating temperature of 70°C, a gap of 110 μm between the scraper and the substrate surface, and scraping to obtain a lead iodide film with a thickness of 590 nm; the fluorine-containing lead iodide precursor solution is prepared by the following steps: preparing a lead iodide precursor solution with a molar concentration of 1.5 mmol / mL, heating and stirring on a constant temperature heating table until completely dissolved, adding hexafluorobenzene as a fluorine-containing additive, and maintaining the heated state to obtain a fluorine-containing lead iodide precursor solution with a volume fraction of the fluorine-containing additive of 20%;

[0108] S4. On the lead iodide film obtained in step S3, a wet film obtained by scraping was annealed at 160° C. for 10 min in an atmosphere with a humidity of 30% to 45% at a speed of 120 mm / min, without heating the substrate, and with a gap of 110 μm between the scraper and the substrate surface, to obtain a perovskite film with a thickness of 610 nm.

[0109] S5, spin coating at a speed of 4500 rpm for 20 seconds to obtain a hole transport layer with a thickness of 200 nm;

[0110] S6. Transfer the substrate with the HTL layer spin-coated from the glove box to a room with a temperature of (25±2)℃ and a humidity of 40%. Use a surgical blade to scrape a 3-4mm gap along the edge of the wafer parallel to the edge. Transfer the wafer to the vacuum coating evaporation chamber of the glove box. Use the evaporation chamber to coat the wafer with HTL layer. Evaporation rate, 1~5nm using Evaporation rate, 5~10nm use Evaporation rate, 10~100nm The evaporation rate was 100 nm to obtain a gold electrode with a thickness of 100 nm.

[0111] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A perovskite solar cell with a high-quality photoactive layer assisted by additives, characterized in that: From bottom to top, it is composed of a substrate, an electron transport layer, an organic-inorganic perovskite structure photoactive layer, a hole transport layer and a back electrode layer. The organic-inorganic perovskite structure photoactive layer is prepared by doping a fluorine-containing additive to assist in preparing a lead iodide film, and then reacting on the lead iodide film to prepare a perovskite film. The fluorine-containing additive doping volume fraction is 1% to 25%, and the fluorine-containing additive is hexafluorobenzene, octafluoronaphthalene, perfluoropentane, perfluorohexane or perfluoroheptane.

2. The perovskite solar cell according to claim 1, characterized in that The organic-inorganic perovskite structure photoactive layer is prepared by a two-step spin coating method or a two-step scraping method.

3. The method for preparing a perovskite solar cell with a high-quality photoactive layer assisted by additives according to claim 1, characterized in that: The steps include: S1, cleaning the substrate; S2, preparing an electron transport layer on the substrate by a solution method; S3. Uniformly coating a fluorine-containing lead iodide precursor solution on the electron transport layer obtained in step S2 to obtain a lead iodide thin film, wherein the fluorine-containing lead iodide precursor solution is prepared according to the following steps: adding a fluorine-containing additive to a lead iodide precursor solution having a molar concentration of 1.2 to 1.5 mmol / mL to obtain a fluorine-containing lead iodide precursor solution having a volume fraction of the fluorine-containing additive of 1% to 25%; S4. Uniformly coating a monovalent halide solution having a molar concentration of 1.2 to 1.5 mmol / mL on the lead iodide film obtained in step S3 to obtain a perovskite film, i.e., an organic-inorganic perovskite structure photoactive layer; S5. A hole transport layer and a back electrode layer are sequentially prepared on the perovskite film obtained in step S4, and finally the perovskite solar cell is obtained.

4. The preparation method according to claim 3, characterized in that The coating method in step S3 or S4 is a scraping method or a spin coating method.

5. The preparation method according to claim 4, characterized in that The specific steps of steps S3 and S4 are: S3. Spin-coating a fluorine-containing lead iodide precursor solution on the electron transport layer obtained in step S2 at a rotation speed of 1500-2000 rpm for 20-40 seconds. After the spin coating is completed, thermal annealing is performed at less than 80° C. for 10-80 seconds to obtain a lead iodide thin film. S4. Spin-coat a monovalent halide solution on the lead iodide film obtained in step S3 at a rotation speed of 1500-2000 rpm for 20-40 s. After the spin coating is completed, anneal the film at 140° C.-160° C. for 10-20 min in an atmosphere with a humidity of 30%-45% to obtain a perovskite film.

6. The preparation method according to claim 4, characterized in that The specific steps of steps S3 and S4 are: S3. Scrape the electron transport layer obtained in step S2 at a speed of 80-120 mm / min, with the transparent substrate heated to less than 80° C. and a gap between the scraper and the substrate surface of 90-110 μm to obtain a lead iodide thin film; S4. On the lead iodide thin film obtained in step S3, a monovalent halide solution is scraped at a speed of 80-120 mm / min. The substrate is not heated, and the gap between the scraper and the substrate surface is 90-110 μm. The wet film obtained by scraping is annealed at 140° C.-160° C. for 10-20 min in an atmospheric environment with a humidity of 30%-45% to obtain a perovskite thin film.

7. The preparation method according to claim 3, characterized in that The monovalent halide of step S4 has the general formula AX, where A is a +1 cation, including FA + 、MA + 、Cs + , Rb + , X is a halide ion, including Cl - Br - , I - .

8. The preparation method according to claim 3, characterized in that The thickness of the electron transport layer is 20-40 nm, the thickness of the organic-inorganic perovskite structure photoactive layer is 580-620 nm, the thickness of the hole transport layer is 100-200 nm, and the thickness of the back electrode layer is 50-100 nm.

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