A perovskite solar cell and its preparation method

Abstract

A perovskite solar cell and its preparation method, belonging to the field of perovskite solar cell technology, overcomes the existing drawback that large-scale thin film preparation using SnO2 as an electron transport layer can lead to increased internal defects in the film, resulting in reduced cell efficiency and stability. The perovskite solar cell of the present invention comprises, from top to bottom, a metal electrode, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer, and a substrate; the electron transport layer comprises tin oxide and diphenylphosphinyl chloride.

Description

Technical Field

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

[0002] In perovskite solar cells, the electron transport layer plays a vital role in the extraction and transport of carriers. Studies have found that the performance of tin oxide (SnO2)-based PSCs is higher than that of titanium dioxide (TiO2)-based PSCs, especially in terms of device stability, indicating that SnO2 has great potential and prospects as an electron transport layer in PSCs. Therefore, SnO2 is widely used as an electron transport layer in perovskite solar cells due to its excellent properties. Commercial SnO2 aqueous colloids can form a dense SnO2 layer by sintering at 150 °C, but more and more studies have found that interface defects still exist in SnO2-based PSCs, and in their large areas (effective area greater than 1 cm 2 During the film preparation process, as the film area increases, the film becomes difficult to form and more holes appear on the film surface. This leads to more internal defects in the prepared film and reduces battery efficiency and stability. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that large-area preparation of thin films when SnO2 is used as an electron transport layer will lead to an increase in internal defects in the thin film and a decrease in battery efficiency and stability, thereby providing a perovskite solar cell and a preparation method thereof.

[0004] To this end, the present invention provides the following technical solutions.

[0005] The present invention provides a perovskite solar cell, which comprises, from top to bottom, a metal electrode, a hole transport layer, a perovskite light absorption layer, an electron transport layer and a substrate;

[0006] The electron transport layer includes tin oxide and diphenylphosphinyl chloride.

[0007] The structural formula of diphenylphosphinyl chloride (DPC) is as follows:

[0008]

[0009] Furthermore, the electron transport layer is prepared from a mixed solution of tin oxide and diphenylphosphinyl chloride, and the mixed solution is formed by mixing a tin oxide solution and a diphenylphosphinyl chloride solution;

[0010] The volume ratio of tin oxide solution to diphenylphosphine chloride solution is 5:(1~5);

[0011] The concentration of the tin oxide solution is 2-4 wt %, and the concentration of the diphenylphosphine chloride solution is 0.5-1.0 mg / ml.

[0012] Furthermore, the perovskite light-absorbing layer is a mono-, di- or ternary cation perovskite light-absorbing layer.

[0013] Furthermore, the hole transport layer is a Spiro-OMeTAD solution;

[0014] The substrate is a FTO conductive substrate.

[0015] Exemplarily, preparing the Spiro-OMeTAD solution includes: using a Spiro-OMeTAD / CB solution, adding Li-TFSI / ACN, tBP, and FK209 / ACN, and mixing to obtain a Spiro-OMeTAD solution.

[0016] Among them, CB is chlorobenzene, Li-TFSI is lithium bis(trifluoromethanesulfonyl)imide, CAN is acetonitrile, and tBP is 4-tert-butylpyridine.

[0017] The present invention also provides a method for preparing a perovskite solar cell, comprising the following steps:

[0018] Step 1: Mix diphenylphosphinyl chloride and tin oxide to prepare a solution for an electron transport layer, and prepare an electron transport layer on a substrate;

[0019] Step 2: preparing a perovskite light absorbing layer on the electron transport layer;

[0020] Step 3, preparing a hole transport layer on the perovskite light absorbing layer;

[0021] Step 4: preparing a metal electrode on the hole transport layer.

[0022] Furthermore, at least one of the conditions (1)-(5) is met:

[0023] (1) In step 1, preparing the electron transport layer includes: spraying the electron transport layer solution onto the substrate and annealing;

[0024] (2) Step 2 includes: preparing a perovskite precursor solution, applying it to the electron transport layer by scraping, and annealing;

[0025] (3) Step 3 includes: scraping the Spiro-OMeTAD solution onto the perovskite light absorbing layer;

[0026] (4) Step 4 includes: evaporating a metal electrode on the hole transport layer by an evaporation method;

[0027] (5) Before step 1, the substrate is also cleaned.

[0028] Furthermore, the solute of the perovskite precursor solution includes at least one of lead iodide (PbI2), cesium iodide (CsI), lead bromide (PbBr2), methylammonium iodide (MAI), formamidinium iodide (FAI), methylammonium bromide (MABr), and methylammonium chloride (MACl).

[0029] Furthermore, the solvent of the perovskite precursor solution is at least one of dimethyl sulfoxide (DMSO), N-dimethylformamide (DMF) and isopropyl alcohol (IPA).

[0030] Furthermore, the cleaning of the substrate includes cleaning the substrate with detergent, deionized water, and ethanol in sequence for 10-20 minutes, and then cleaning the substrate with an ultraviolet ozone cleaning machine for 10-20 minutes.

[0031] Furthermore, in step 4, a gold electrode with a thickness of 100 to 150 nm is evaporated, illustratively, by using a high resistance vacuum evaporator.

[0032] The thickness of the perovskite light-absorbing layer is 300-500 nm.

[0033] Optionally, the perovskite light absorbing layer is a mono-perovskite light absorbing layer MAPbI3; the binary perovskite light absorbing layer FA x MA 1- x PbI30<x<1 or ternary perovskite light absorbing layer Cs x (FA y MA 1-y ) 1-x Pb(Br 0.15 I 0.85 )3, 0<x<1, 0<y<1. For example, the monolithic perovskite light absorbing layer can be MAPbI3, the binary perovskite light absorbing layer can be FA 0.92 MA 0.08 PbI3, ternary is Cs 0.05 (FA 0.85 MA 0.15 ) 0.95 Pb(Br 0.15 I 0.85 )3.

[0034] The technical solution of the present invention has the following advantages:

[0035] 1. The perovskite solar cell provided by the present invention comprises, from top to bottom, a metal electrode, a hole transport layer, a perovskite light-absorbing layer, an electron transport layer and a substrate; the electron transport layer comprises tin oxide and diphenylphosphinoyl chloride.

[0036] The present invention uses diphenylphosphine chloride (DPC) to dope tin oxide. The newly formed P-Sn bond changes the electron cloud density around the Sn atom, which helps to improve the electron mobility of the SnO2 electron transport layer. Therefore, the open circuit voltage of the PSC based on SnO2-DPC is increased. By introducing DPC into the SnO2, Cl + Ions can escape into the interstitial sites of the tin oxide lattice, inhibiting ion migration and reducing nonradiative recombination, which helps improve the open-circuit voltage of PSCs and suppress hysteresis. This also reduces the trap density at the SnO2 / perovskite interface, leading to an increase in the PSC's current. Doping the tin oxide electron transport layer with DPC simultaneously passivates both the electron transport layer and the perovskite subinterface, addressing the poor film quality and performance-hindering issues of large-area devices in perovskite solar cells. Furthermore, using DPC as a modified material can reduce production costs.

[0037] 2. The present invention provides a method for preparing a perovskite solar cell, comprising the following steps: Step 1, mixing diphenylphosphinic chloride and tin oxide to prepare an electron transport layer solution, and preparing an electron transport layer on a substrate; Step 2, preparing a perovskite light-absorbing layer on the electron transport layer; Step 3, preparing a hole transport layer on the perovskite light-absorbing layer; Step 4, preparing a metal electrode on the hole transport layer. The present invention uses a mixed solution of diphenylphosphinic chloride and tin oxide to prepare the electron transport layer, making it suitable for the preparation of large-area thin films, compensating for the poor film quality of large-area devices in perovskite solar cells and significantly improving the efficiency of the devices.

[0038] The fabrication method for perovskite solar cells utilizes a doctor blade coating method to create perovskite light-absorbing layers of varying compositions. This process is a strictly quantitative method with high repeatability and controllability during the coating process, saving significant amounts of experimental chemicals. The resulting perovskite thin films exhibit uniform grain size, high film uniformity, and high crystalline quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0040] Figure 1 Schematic diagram of the preparation process of the solar cell in Example 1.

[0041] Figure 2 It is a structural diagram of the solar cell prepared by the present invention.

[0042] Figure 3This is the current-voltage curve of the solar cell prepared in Comparative Example 1 of the present invention.

[0043] Figure 4 This is the current-voltage curve of the solar cell prepared in Example 1 of the present invention.

[0044] Figure 5 This is the current-voltage curve of the solar cell prepared in Comparative Example 2 of the present invention.

[0045] Figure 6 This is the current-voltage curve of the solar cell prepared in Example 2 of the present invention.

[0046] Figure 7 This is the current-voltage curve of the solar cell prepared in Comparative Example 3 of the present invention.

[0047] Figure 8 3 is the current-voltage curve of the solar cell prepared in Example 3 of the present invention.

[0048] Figure 9 This is the current-voltage curve of the solar cell prepared in Comparative Example 4 of the present invention.

[0049] Figure 10 This is the current-voltage curve of the solar cell prepared in Example 4 of the present invention.

[0050] Figure 11 This is the current-voltage curve of the solar cell prepared in Comparative Example 5 of the present invention.

[0051] Figure 12 This is the current-voltage curve of the solar cell prepared in Example 5 of the present invention. DETAILED DESCRIPTION

[0052] The following examples are provided for a better understanding of the present invention and are not intended to limit the best mode of implementation. They do not limit the content and scope of protection of the present invention. Any product identical or similar to the present invention obtained by anyone under the guidance of the present invention or by combining the features of the present invention with other prior arts shall fall within the scope of protection of the present invention.

[0053] If no specific experimental steps or conditions are specified in the examples, the conventional experimental steps or conditions described in the literature in this field can be used. If the manufacturer of the reagents or instruments is not specified, they are all commercially available conventional reagents.

[0054] Example 1

[0055] This embodiment provides a method for preparing a perovskite solar cell. Figure 1 As shown, the following steps are included:

[0056] Cleaning the substrate: The FTO conductive substrate was ultrasonically cleaned with soapy water, deionized water, and ethanol for 20 min, respectively, and then irradiated with ultraviolet light for 15 min.

[0057] Step 1: Spraying to prepare the electron transport layer:

[0058] (1) Preparation of electron transport layer solution:

[0059] Tin oxide colloid (13.75 wt%) was mixed with ultrapure water and ultrasonically shaken for 20 min to obtain a 3.75 wt% tin oxide solution. 0.5 mg of diphenylphosphinyl chloride was dissolved in 1 mL of ultrapure water to obtain a 0.5 mg / mL modified solution. The above tin oxide solution and the diphenylphosphinyl chloride modified solution were mixed in a volume ratio of 5:1 and ultrasonically shaken for 20-30 min to prepare a mixed electron transport layer solution.

[0060] (2) Turn on the dry air generator and compress the air to a pressure of 0.4 MPa. Place a 5 cm × 5 cm FTO conductive substrate on a glass slide and secure it with high-temperature tape. Place the glass slide on a 100°C hot plate with the air gun at a distance of 15 cm from the slide. Maintain the temperature for 1 min. Connect the air gun to the mixed electron transport layer solution, turn on the air gun, and spray the spray from the air gun. After the spray stabilizes, move the air gun from one end of the glass slide to the other, back and forth, and continue spraying for 1 min before stopping. Anneal the glass slide on the hot plate at 100°C for 10 min and then remove it.

[0061] Step 2: Prepare the perovskite light-absorbing layer by scraping:

[0062] Preparation of perovskite precursor solution: 0.145 g of MAI powder and 0.463 g of PbI2 powder were dissolved in a mixed solution of DMF (900 μL) and DMSO (100 μL) and stirred at 500 rpm / min for 2 h to obtain a monobasic perovskite precursor solution.

[0063] 300 μL of the monovalent perovskite precursor solution was dropped onto the electron transport layer (5 cm × 5 cm) to form a horizontal line. A coater was then moved at a speed of 4 mm / s, with the blade positioned 0.48 mm above the substrate. The perovskite was then annealed at 150°C for 15 minutes to crystallize.

[0064] Step 3: Prepare the hole transport layer by scraping:

[0065] To 1 ml of Spiro-OMeTAD / CB (72.3 mg / mL) solution, add 17.8 µl of Li-TFSI / ACN (520 mg / mL), 28.5 µl of tBP, and 30 µl of FK209 / ACN (300 mg / mL), and mix to obtain the Spiro-OMeTAD solution.

[0066] After cooling the device prepared in step 2, 200 μL of Spiro-OMeTAD solution was scraped onto the perovskite light-absorbing layer to form a film.

[0067] Step 4: Electrode evaporation: Place the obtained device into an evaporator and deposit a 100 nm thick Au electrode by thermal evaporation to obtain a complete perovskite solar cell.

[0068] Example 2

[0069] This embodiment provides a method for preparing a perovskite solar cell, comprising the following steps:

[0070] Cleaning the substrate: The FTO conductive substrate was ultrasonically cleaned with detergent, deionized water, and ethanol for 20 min, respectively, and then irradiated with ultraviolet (UV) light for 15 min.

[0071] Step 1: Spraying to prepare the electron transport layer:

[0072] (1) Preparation of electron transport layer solution:

[0073] Tin oxide colloid (13.75 wt%) was mixed with ultrapure water and ultrasonically shaken for 20 min to obtain a 2.75 wt% tin oxide solution; 0.5 mg of diphenylphosphinyl chloride was dissolved in 1 mL of ultrapure water to obtain a 0.5 mg / mL modified solution, and the above tin oxide solution and diphenylphosphinyl chloride modified solution were mixed in a volume ratio of 5:2 and ultrasonically shaken for 20-30 min to prepare a mixed electron transport layer solution.

[0074] (2) Turn on the dry air generator and compress the air to a pressure of 0.4 MPa. Place a 5 cm × 5 cm FTO conductive substrate on a glass slide and secure it with high-temperature tape. Place the glass slide on a 100°C hot plate with the air gun at a distance of 15 cm from the slide. Maintain the temperature for 1 min. Connect the air gun to the mixed electron transport layer solution, turn on the air gun, and spray the spray from the air gun. After the spray stabilizes, move the air gun from one end of the glass slide to the other, back and forth, and continue spraying for 1 min before stopping. Anneal the glass slide on the hot plate at 100°C for 10 min and then remove it.

[0075] Step 2: Prepare the perovskite light-absorbing layer by scraping:

[0076] 0.486 g of PbI2 powder was dissolved in a mixture of DMF (900 μL) and DMSO (100 μL) and stirred at 500 rpm / min for 2 hours to obtain a lead iodide precursor solution. 0.16 g of FAI and 0.01 g of MACl powder were dissolved in 1 mL of IPA and stirred at 500 rpm / min for 2 hours to obtain an ammonium salt precursor solution.

[0077] In the first step, 150 μL of a lead iodide precursor solution was dropped onto the electron transport layer (5 cm × 5 cm) to form a horizontal line. A coater was then moved at a speed of 5 mm / s, with the blade height controlled to 0.5 mm above the substrate. The wet film was then annealed on a hotplate at 70°C for 1 minute to dry it.

[0078] In the second step, after cooling to room temperature, 200 μL of ammonium salt precursor solution was scraped onto the PbI2 film, and then annealed at 150 °C for 15 min to crystallize the perovskite.

[0079] Step 3: Prepare the hole transport layer by scraping:

[0080] To 1 ml of Spiro-OMeTAD / CB (72.3 mg / mL) solution, add 17.8 µl of Li-TFSI / ACN (520 mg / mL), 28.5 µl of tBP, and 30 µl of FK209 / ACN (300 mg / mL), and mix to obtain the Spiro-OMeTAD solution.

[0081] After the device prepared in step 2 is cooled, 200 μL of Spiro-OMeTAD solution is scraped onto the perovskite light-absorbing layer to form a film.

[0082] Step 4: Electrode evaporation: Place the obtained device into an evaporator and deposit a 150 nm thick Au electrode by thermal evaporation to obtain a complete perovskite solar cell.

[0083] Example 3

[0084] This embodiment provides a method for preparing a perovskite solar cell, comprising the following steps:

[0085] Cleaning the substrate: The FTO conductive substrate was ultrasonically cleaned with detergent, deionized water, and ethanol for 20 min, respectively, and then irradiated with ultraviolet (UV) light for 15 min.

[0086] Step 1: Spraying to prepare the electron transport layer:

[0087] (1) Preparation of electron transport layer solution:

[0088] Tin oxide colloid (13.75 wt%) was mixed with ultrapure water and ultrasonically shaken for 20 min to obtain a 3.75 wt% tin oxide solution. 1 mg of diphenylphosphinyl chloride was dissolved in 1 mL of ultrapure water to obtain a 1 mg / mL modified solution. The above tin oxide solution and diphenylphosphinyl chloride modified solution were mixed in a volume ratio of 5:1 and ultrasonically shaken for 20-30 min to prepare a mixed electron transport layer solution.

[0089] (2) Turn on the dry air generator and compress the air to a pressure of 0.4 MPa. Place a 5 cm × 5 cm FTO conductive substrate on a glass slide and secure it with high-temperature tape. Place the glass slide on a 100°C hot plate with the air gun at a distance of 15 cm from the slide. Maintain the temperature for 1 min. Connect the air gun to the mixed electron transport layer solution, turn on the air gun, and spray the spray from the air gun. After the spray stabilizes, move the air gun from one end of the glass slide to the other, back and forth, and continue spraying for 1 min before stopping. Anneal the glass slide on the hot plate at 100°C for 10 min and then remove it.

[0090] Step 2: Prepare the perovskite light-absorbing layer by scraping:

[0091] Preparation of perovskite precursor solution: 0.175 g of FAI, 0.02 g of MABr, 0.5 g of PbI2, and 0.072 g of PbBr2 powder were dissolved in a mixed solution of DMF (900 μL) and DMSO (100 μL) and stirred at 500 rpm / min for 2 hours. Then, 0.005 g of CsI was added to the above perovskite precursor mixed solution and stirred for two hours to obtain a ternary mixed cation perovskite precursor solution.

[0092] 200 μL of the ternary perovskite precursor solution was dropped onto the electron transport layer (5 cm × 5 cm) to form a horizontal line. A coater was then moved at a speed of 4 mm / s, with the blade height controlled to 0.48 mm above the substrate. The perovskite was then annealed at 150°C for 15 minutes to crystallize.

[0093] Step 3: Prepare the hole transport layer by scraping:

[0094] To 1 ml of Spiro-OMeTAD / CB (72.3 mg / mL) solution, add 17.8 µl of Li-TFSI / ACN (520 mg / mL), 28.5 µl of tBP, and 30 µl of FK209 / ACN (300 mg / mL), and mix to obtain the Spiro-OMeTAD solution.

[0095] After the device prepared in step 2 was cooled, 300 μL of Spiro-OMeTAD solution was scraped onto the perovskite light-absorbing layer to form a film.

[0096] Step 4: Electrode evaporation: Place the obtained device into an evaporator and deposit a 150 nm thick Au electrode by thermal evaporation to obtain a complete perovskite solar cell.

[0097] Example 4

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

[0099] Cleaning the substrate: The FTO conductive substrate was ultrasonically cleaned with soapy water, deionized water, and ethanol for 10 min, respectively, and then irradiated with ultraviolet light for 20 min.

[0100] Step 1: Spraying to prepare the electron transport layer:

[0101] (1) Preparation of electron transport layer solution:

[0102] Tin oxide colloid (13.75 wt%) was mixed with ultrapure water and ultrasonically shaken for 20 minutes to obtain a 3.75 wt% tin oxide solution. 0.5 mg of diphenylphosphinoyl chloride was dissolved in 1 mL of ultrapure water to obtain a 0.5 mg / mL modified solution, which was mixed with the above-mentioned tin oxide solution in a volume ratio of 5:2 and ultrasonically shaken for 20-30 minutes to prepare a mixed electron transport layer solution.

[0103] (2) Turn on the dry air generator and compress the air to a pressure of 0.4 MPa. Place a 5 cm × 5 cm FTO conductive substrate on a glass slide and secure it with high-temperature tape. Place the glass slide on a 100°C hot plate with the air gun at a distance of 15 cm from the slide. Maintain the temperature for 1 min. Connect the air gun to the mixed electron transport layer solution, turn on the air gun, and spray the spray from the air gun. After the spray stabilizes, move the air gun from one end of the glass slide to the other, back and forth, and continue spraying for 1 min before stopping. Anneal the glass slide on the hot plate at 100°C for 10 min and then remove it.

[0104] Step 2: Prepare the perovskite light-absorbing layer by scraping:

[0105] Preparation of perovskite precursor solution: 0.145 g of MAI powder and 0.463 g of PbI2 powder were dissolved in a mixed solution of DMF (900 μL) and DMSO (100 μL) and stirred at 500 rpm / min for 2 h to obtain a monobasic perovskite precursor solution.

[0106] 300 μL of the monovalent perovskite precursor solution was dropped onto the electron transport layer (5 cm × 5 cm) to form a horizontal line. A coater was then moved at a speed of 4 mm / s, with the blade positioned 0.48 mm above the substrate. The perovskite was then annealed at 150°C for 15 minutes to crystallize.

[0107] Step 3: Prepare the hole transport layer by scraping:

[0108] To 1 ml of Spiro-OMeTAD / CB (72.3 mg / mL) solution, add 17.8 µl of Li-TFSI / ACN (520 mg / mL), 28.5 µl of tBP, and 30 µl of FK209 / ACN (300 mg / mL), and mix to obtain the Spiro-OMeTAD solution.

[0109] After cooling the device prepared in step 2, 200 μL of Spiro-OMeTAD solution was scraped onto the perovskite light-absorbing layer to form a film.

[0110] Step 4: Electrode evaporation: Place the obtained device into an evaporator and deposit a 100 nm thick Au electrode by thermal evaporation to obtain a complete perovskite solar cell.

[0111] Example 5

[0112] This embodiment provides a method for preparing a perovskite solar cell, comprising the following steps:

[0113] Cleaning the substrate: The FTO conductive substrate was ultrasonically cleaned with soapy water, deionized water, and ethanol for 15 min, respectively, and then irradiated with ultraviolet light for 10 min.

[0114] Step 1: Spraying to prepare the electron transport layer:

[0115] (1) Preparation of electron transport layer solution:

[0116] Tin oxide colloid (13.75 wt%) was mixed with ultrapure water and ultrasonically shaken for 20 minutes to obtain a 2.75 wt% tin oxide solution. 1 mg of diphenylphosphinoyl chloride was dissolved in 1 mL of ultrapure water to obtain a 1 mg / mL modification solution, which was mixed with the above-mentioned tin oxide solution in a volume ratio of 5:3 and ultrasonically shaken for 20-30 minutes to prepare a mixed electron transport layer solution.

[0117] (2) Turn on the dry air generator and compress the air to a pressure of 0.4 MPa. Place a 5 cm × 5 cm FTO conductive substrate on a glass slide and secure it with high-temperature tape. Place the glass slide on a 100°C hot plate with the air gun at a distance of 15 cm from the slide. Maintain the temperature for 1 min. Connect the air gun to the mixed electron transport layer solution, turn on the air gun, and spray the spray from the air gun. After the spray stabilizes, move the air gun from one end of the glass slide to the other, back and forth, and continue spraying for 1 min before stopping. Anneal the glass slide on the hot plate at 100°C for 10 min and then remove it.

[0118] Step 2: Prepare the perovskite light-absorbing layer by scraping:

[0119] Preparation of perovskite precursor solution: 0.145 g of MAI powder and 0.463 g of PbI2 powder were dissolved in a mixed solution of DMF (900 μL) and DMSO (100 μL) and stirred at 500 rpm / min for 2 h to obtain a monobasic perovskite precursor solution.

[0120] 300 μL of the monovalent perovskite precursor solution was dropped onto the electron transport layer (5 cm × 5 cm) to form a horizontal line. A coater was then moved at a speed of 4 mm / s, with the blade positioned 0.48 mm above the substrate. The perovskite was then annealed at 150°C for 15 minutes to crystallize.

[0121] Step 3: Prepare the hole transport layer by scraping:

[0122] To 1 ml of Spiro-OMeTAD / CB (72.3 mg / mL) solution, add 17.8 µl of Li-TFSI / ACN (520 mg / mL), 28.5 µl of tBP, and 30 µl of FK209 / ACN (300 mg / mL), and mix to obtain the Spiro-OMeTAD solution.

[0123] After cooling the device prepared in step 2, 200 μL of Spiro-OMeTAD solution was scraped onto the perovskite light-absorbing layer to form a film.

[0124] Step 4: Electrode evaporation: Place the obtained device into an evaporator and deposit a 130 nm thick Au electrode by thermal evaporation to obtain a complete perovskite solar cell.

[0125] Comparative Example 1

[0126] This comparative example is basically the same as Example 1, except that the tin oxide solution is not doped with DPC.

[0127] Comparative Example 2

[0128] This comparative example is substantially the same as Example 2, except that the tin oxide solution is not doped with DPC.

[0129] Comparative Example 3

[0130] This comparative example is substantially the same as Example 2, except that the tin oxide solution is not doped with DPC.

[0131] Comparative Example 4

[0132] This comparative example is substantially the same as Example 4, except that the tin oxide solution is not doped with DPC.

[0133] Comparative Example 5

[0134] This comparative example is substantially the same as Example 5, except that the tin oxide solution is not doped with DPC.

[0135] Test example

[0136] The structure of the perovskite solar cell prepared by the present invention is shown in FIG. Figure 2 As shown, the photoelectric conversion efficiency of the perovskite solar cells prepared in the embodiment and the comparative example was tested. The test method is as follows: the cell conversion efficiency is tested on an electrochemical workstation. The light intensity is calibrated to AM1.5G one sun (100 mW / cm 2 The effective active area of the solar cell device prepared on a 5 cm × 5 cm sample is 19.3 cm 2 The JV curves were measured in the range of 1.2 V to -0.1 V at a scan rate of 100 mV / s.

[0137] The current-voltage curve is as follows Figure 3-Figure 12 As shown in Table 1, the photoelectric conversion efficiency of a solar cell = (voltage × current × fill factor) / (cell area × light intensity) × 100%. The photoelectric conversion efficiency of a solar cell is shown in Table 1. The photoelectric conversion efficiency improvement rate = (photoelectric conversion efficiency of the embodiment - photoelectric conversion efficiency of the corresponding comparative example) / photoelectric conversion efficiency of the corresponding comparative example.

[0138] Table 1 Photoelectric conversion efficiency of solar cells

[0139]

[0140] As can be seen from Table 1, the photoelectric conversion efficiency of the solar cell prepared by the present invention is significantly improved.

[0141] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A perovskite solar cell, characterized in that From top to bottom, it includes metal electrode, hole transport layer, perovskite light absorption layer, electron transport layer and substrate; The electron transport layer includes tin oxide and diphenylphosphinyl chloride; The electron transport layer is prepared from a mixed solution of tin oxide and diphenylphosphinyl chloride, wherein the mixed solution is formed by mixing a tin oxide solution and a diphenylphosphinyl chloride solution; The volume ratio of the tin oxide solution to the diphenylphosphine chloride solution is 5:(1-5); The concentration of the tin oxide solution is 2-4 wt %, and the concentration of the diphenylphosphine chloride solution is 0.5-1.0 mg / ml.

2. The perovskite solar cell according to claim 1, characterized in that The perovskite light-absorbing layer is a mono-, di- or ternary cation perovskite light-absorbing layer.

3. The perovskite solar cell according to claim 1, wherein The hole transport layer is a Spiro-OMeTAD solution; The substrate is a FTO conductive substrate.

4. A method for preparing a perovskite solar cell according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: Mix diphenylphosphinyl chloride and tin oxide to prepare a solution for an electron transport layer, and prepare an electron transport layer on a substrate; Step 2: preparing a perovskite light absorbing layer on the electron transport layer; Step 3, preparing a hole transport layer on the perovskite light absorbing layer; Step 4: preparing a metal electrode on the hole transport layer.

5. The method for preparing a perovskite solar cell according to claim 4, wherein: Satisfy at least one of the following conditions (1)-(5): (1) In step 1, preparing the electron transport layer includes: spraying the electron transport layer solution onto the substrate and annealing; (2) Step 2 includes: preparing a perovskite precursor solution, applying the solution to the electron transport layer, and annealing the solution; (3) Step 3 includes: scraping the Spiro-OMeTAD solution onto the perovskite light absorbing layer; (4) Step 4 includes: evaporating a metal electrode on the hole transport layer by an evaporation method; (5) Before step 1, the substrate is also cleaned.

6. The method for preparing a perovskite solar cell according to claim 5, wherein: The solute of the perovskite precursor solution includes at least one of lead iodide, cesium iodide, lead bromide, methylammonium iodide, formamidine iodide, methylammonium bromide and methylammonium chloride.

7. The method for preparing a perovskite solar cell according to claim 6, wherein: The solvent of the perovskite precursor solution is at least one of dimethyl sulfoxide, N-N-dimethylformamide and isopropyl alcohol.

8. The method for preparing a perovskite solar cell according to any one of claims 5 to 7, wherein: The cleaning of the substrate comprises cleaning the substrate with detergent, deionized water, and ethanol in sequence for 10-20 minutes, and then cleaning the substrate with an ultraviolet ozone cleaning machine for 10-20 minutes.

9. The method for preparing a perovskite solar cell according to any one of claims 5 to 7, wherein: In step 4, a gold electrode with a thickness of 100 to 150 nm is evaporated.

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