A method for preparing a perovskite solar cell and a perovskite solar cell

Abstract

The present invention provides a method for preparing a perovskite solar cell and a perovskite solar cell. In the process of preparing a perovskite layer, a dopant is added to a configured perovskite precursor solution so that the prepared perovskite layer is doped with a dopant, and the dopant includes 4-bromo-3-trifluoromethoxybenzonitrile. The beneficial effects of the present invention are to fill (passivate) the defects at the perovskite grain boundary and improve the photoelectric conversion efficiency of the battery; the passivation effect of the passivator on the perovskite grain boundary defects is utilized to suppress the adverse effects of water, heat and light on the perovskite solar cell, and enhance the stability of the battery efficiency under water, heat and light environments.

Description

Technical Field

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

[0002] In the more than a decade since the birth of perovskite solar cells in the laboratory, its photoelectric conversion efficiency has grown rapidly and has now reached 26.7%. Moreover, perovskite materials have flexible and adjustable band gaps, long carrier diffusion lengths, high ultraviolet-visible light absorption coefficients, and low preparation costs, and are expected to achieve large-scale practical applications in the future. However, as an ionic crystalline material, perovskite is very easy to absorb moisture from the air, and water molecules can cause serious damage to the skeleton structure of perovskite. Moreover, in the process of forming perovskite films with the help of solvent methods, a large number of edge ion vacancy defects will be left at the grain boundaries inside the perovskite film, making it easy for photogenerated carriers to undergo non-radiative recombination at these locations, resulting in battery voltage and current losses. In addition, the imbalance of the stoichiometric components at this boundary position will cause the perovskite film to be easily degraded under the action of water, heat, and light, causing the battery efficiency to continue to decline under the working environment.

[0003] Prior art CN106062983A and CN110061139A disclose that by using a small molecule halogenated organic compound as a passivator in supramolecular assembly, a perovskite solar cell with better photoelectric efficiency and stability than traditional passivators is obtained. Prior art CN116322094A discloses a sulfur-containing passivator to passivate perovskite solar cells; patent CN117114143A discloses a set of perovskite passivator performance evaluation strategies. Patent CN118125963A discloses phenylimide organic iodide as a passivator, which reduces the defects of perovskite crystals and improves the photoelectric conversion efficiency and service life of perovskite solar cells.

[0004] However, in the perovskite film prepared by the solvent method, there are a large number of defects at the grain boundaries, which are not conducive to the separation and transmission of photogenerated carriers, resulting in a decline in battery performance and limiting the battery's photoelectric conversion efficiency. The defects at the grain boundaries will make the perovskite crystals easily damaged by water, heat and light, causing the battery efficiency to gradually decrease and limiting its service life. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for preparing a perovskite solar cell and a perovskite solar cell to solve the above or other problems existing in the prior art.

[0006] To solve the above technical problems, the technical solution adopted by the present invention is: a method for preparing a perovskite solar cell, in the process of preparing a perovskite layer, adding a dopant to a configured perovskite precursor solution, so that the prepared perovskite layer is doped with the dopant, and the dopant includes 4-bromo-3-trifluoromethoxybenzonitrile.

[0007] Furthermore, the dopant is added to the prepared perovskite precursor solution in a certain ratio relative to the molar number of PbI2.

[0008] Further, the ratio is 0.1%-1.0%.

[0009] Further, the ratio is 0.3%-0.6%.

[0010] Further, the preparation of the perovskite layer includes the following steps:

[0011] In a first gas environment, a perovskite precursor solution doped with a dopant is applied to a substrate provided with a hole transport layer by spin coating;

[0012] Annealing treatment is performed to obtain a perovskite layer.

[0013] Further, the first gas is nitrogen;

[0014] When performing spin coating, the first spin coating and the second spin coating are performed sequentially, and the anti-solvent is added dropwise before the second spin coating is completed, so that the perovskite crystals are precipitated.

[0015] Furthermore, the steps of preparing the perovskite precursor solution include: adding CsI, FAI and PbI2 to a mixed solution of DMF and DMSO to prepare a first solution, adding MABr and PbBr2 to a mixed solution of DMF and DMSO to prepare a second solution, and mixing the first solution with the second solution to obtain a perovskite precursor solution.

[0016] Furthermore, the chemical formula of the perovskite precursor solution is MA 0.05 (Cs 0.05 FA 0.95 ) 0.95 Pb(I 0.95 Br 0.05 )3.

[0017] Furthermore, before preparing the perovskite layer, it also includes preparing a substrate with a hole transport layer;

[0018] After the perovskite layer is prepared, the electron transport layer, passivation layer and metal electrode are prepared in sequence.

[0019] A perovskite solar cell is prepared by the above-mentioned method for preparing a perovskite solar cell. The perovskite layer of the perovskite solar cell is doped with a dopant, and the dopant includes 4-bromo-3-trifluoromethoxybenzonitrile.

[0020] Due to the adoption of the above technical solution, in the process of preparing perovskite solar cells, when preparing the perovskite layer, a dopant is added to the configured perovskite precursor solution. The dopant can be 4-bromo-3-trifluoromethoxybenzonitrile, which is added to the configured perovskite precursor solution in a certain proportion. The dopant serves as a defect passivator of the perovskite layer in the perovskite solar cell, fills (passivates) the defects at the perovskite grain boundaries, and improves the photoelectric conversion efficiency of the cell; the passivation effect of the passivator on the defects at the perovskite grain boundaries is utilized to inhibit the adverse effects of water, heat and light on the perovskite solar cell, and enhance the stability of the cell efficiency in water, heat and light environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of a perovskite solar cell according to an embodiment of the present invention.

[0022] In the figure:

[0023] 1. Substrate; 2. ITO conductive layer; 3. Hole transport layer; 4. Perovskite layer; 5. Electron transport layer; 6. Passivation layer; 7. Metal electrode. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0025] Figure 1 A schematic structural diagram of a perovskite solar cell according to an embodiment of the present invention is shown. The present invention relates to a method for preparing a perovskite solar cell and a perovskite solar cell. When preparing the perovskite solar cell, a dopant is added to a configured perovskite precursor solution. The dopant can be used as a defect passivator for the perovskite layer in the perovskite solar cell, effectively reducing the defect density in the perovskite film, while improving the hydrophobicity of the perovskite film, and improving the photoelectric conversion efficiency and stability of the perovskite solar cell device.

[0026] A method for preparing a perovskite solar cell, such as Figure 1As shown, before preparing the perovskite layer 4, a dopant is added to the configured perovskite precursor solution, and then the perovskite precursor solution doped with the dopant is used to prepare the perovskite layer 4 on the hole transport layer 3. The perovskite layer 4 is a thin film structure, so that the prepared perovskite film is doped with the dopant. The dopant can be used as a defect passivator of the perovskite layer 4 in the perovskite solar cell, and the defects at the grain boundaries in the perovskite film are modified to improve the photoelectric conversion efficiency and stability of the perovskite solar cell.

[0027] In some embodiments, the dopant includes 4-bromo-3-trifluoromethoxybenzonitrile, and the structural formula of 4-bromo-3-trifluoromethoxybenzonitrile is: The Br atom at the end of the molecule is used to compensate for the surface ion vacancies that occur during the preparation of the perovskite film, and combined with the uncoordinated lead ions, the defect density in the perovskite film is effectively reduced. At the same time, with the help of the hydrophobic group (trifluoromethoxy) of the organic molecule, the hydrophobic properties of the modified perovskite film are effectively improved, preventing water molecules from destroying the lattice structure, so that the modified perovskite solar cell device has a significant improvement in efficiency and stability.

[0028] When the above-mentioned dopants are added, the dopants are added to the configured perovskite precursor solution in a certain proportion relative to the molar number of PbI2, and the proportion is 0.1%-1.0%. The proportion can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, etc. Any proportion value between 0.1%-1.0% is selected according to actual needs, and no specific requirements are made here.

[0029] In some feasible embodiments, preferably, the addition ratio of the above-mentioned dopant relative to the molar number of PbI2 is 0.3%-0.6%.

[0030] After the dopant is added into the perovskite precursor solution, the perovskite precursor solution doped with the dopant is used to prepare a perovskite layer.

[0031] The steps of preparing the above-mentioned perovskite precursor solution include: adding CsI, FAI and PbI2 to a mixed solution of DMF and DMSO to prepare a first solution, adding MABr and PbBr2 to a mixed solution of DMF and DMSO to prepare a second solution, and mixing the first solution with the second solution to obtain a perovskite precursor solution. The chemical formula of the perovskite precursor solution is MA 0.05 (Cs 0.05 FA 0.95 ) 0.95 Pb(I 0.95 Br 0.05 )3.

[0032] After the perovskite precursor solution is prepared, a dopant is added to the perovskite precursor solution. The dopant is added to the prepared perovskite precursor solution in a certain ratio relative to the molar number of PbI2 to obtain a perovskite precursor solution doped with a dopant. The ratio is 0.1%-1.0%, and preferably, the ratio is 0.3%-0.6%.

[0033] The perovskite precursor solution doped with the dopant is used to prepare the perovskite layer 4, comprising the following steps:

[0034] In a first gas environment, a perovskite precursor solution doped with a dopant is applied to a substrate 1 provided with a hole transport layer 3 by spin coating: in this step, a perovskite precursor solution doped with a dopant is dripped onto the prepared substrate 1 with the hole transport layer 3, and the solution is coated by spin coating to coat the perovskite precursor solution doped with a dopant on the hole transport layer 3. When spin coating is performed, the first spin coating and the second spin coating are performed in sequence, and an anti-solvent is dripped before the second spin coating is completed to precipitate perovskite crystals;

[0035] During the first spin coating, the spin coating is performed at a first rotation speed and for a first time;

[0036] During the second spin coating, the spin coating is performed at a second rotation speed until the spin coating is completed;

[0037] Among them, the first speed is 1000-2000rpm, the first time is 5-15s, and the second speed is 5000-6000rpm. The first speed, the first time and the second speed are selected according to actual needs, and no specific requirements are made here.

[0038] Before the coating of the perovskite precursor solution doped with the dopant is completed, an anti-solvent is added to allow the perovskite crystals to precipitate. Specifically, during the spin coating at a second speed, an anti-solvent is added within a second time before the spin coating is completed to allow the perovskite crystals to precipitate. The second time is 3-8s. The first time is selected according to actual needs and no specific requirements are made here.

[0039] In some feasible embodiments, the anti-solvent can be anisole, chlorobenzene or ethyl acetate, preferably anisole, and the added volume of the anti-solvent is 5-1.5 mL. The added volume of the anti-solvent is selected according to actual needs and no specific requirements are made here.

[0040] In some feasible embodiments, the first gas is preferably nitrogen or argon.

[0041] Annealing is performed to prepare a perovskite film, that is, a perovskite layer 4 is formed on the hole transport layer 3; in this step, the substrate 1 coated with the perovskite precursor solution doped with a dopant is placed on a heating plate for annealing, the annealing temperature is 100-110°C, and the annealing time is 10-15min. The annealing temperature and annealing time are selected according to actual needs, and no specific requirements are made here.

[0042] The perovskite solar cell, when prepared, also includes:

[0043] Before preparing the perovskite layer 4, the process further includes preparing a substrate 1 with a hole transport layer 3, including the following steps:

[0044] A substrate 1 is provided, and the substrate 1 is etched and cleaned to improve the cleanliness of the substrate 1: the substrate 1 is a glass substrate with a highly transparent conductive layer of indium tin oxide (ITO), and a required pattern is etched on the substrate 1 using a laser etcher;

[0045] After the etching is completed, the substrate 1 is cleaned for the first time: dust and other impurities on the substrate 1 are removed using a dust-free cloth and deionized water;

[0046] After the first cleaning treatment is completed, the substrate 1 is subjected to a second cleaning treatment, and the second cleaning treatment is ultrasonic cleaning, and the substrate 1 is placed in deionized water, ethanol and isopropanol for ultrasonic cleaning in sequence, and the ultrasonic cleaning time is 20-40 minutes, that is, the substrate 1 is placed in deionized water for ultrasonic cleaning, and the ultrasonic cleaning time is 20-40 minutes, and then the substrate 1 is placed in ethanol for ultrasonic cleaning, and the ultrasonic cleaning time is 20-40 minutes, and then the substrate 1 is placed in isopropanol for ultrasonic cleaning, and the ultrasonic cleaning time is 20-40 minutes;

[0047] After the second cleaning treatment, the substrate 1 is cleaned for the third time. The third cleaning treatment is ultraviolet ozone treatment. The substrate 1 is cleaned for the third time using an ultraviolet ozone cleaning machine to remove organic impurities remaining on the surface of the substrate 1. The third cleaning treatment takes 25-45 minutes.

[0048] After the substrate 1 is etched and cleaned, the hole transport layer 3 is prepared, which includes the following steps:

[0049] Preparation of hole transport layer precursor solution: weigh a certain weight of MeO-2PACz, and add the MeO-2PACz to ethanol, MeO-2PACz is dissolved in ethanol, and a hole transport layer precursor solution of a certain concentration is obtained, wherein the weight of MeO-2PACz is 1-2 mg, and the volume of ethanol is 1-3 mL. The weight of MeO-2PACz and the volume of ethanol are selected according to actual needs, and no specific requirements are made here. The concentration of the prepared hole transport layer precursor solution is 0.5-1 mg / mL.

[0050] Preparing a hole transport layer 3 on a substrate 1: coating a hole transport layer precursor solution on the cleaned substrate 1, and performing an annealing treatment to prepare a hole transport layer 3 on the substrate 1. When coating the hole transport layer precursor solution, spin coating is performed, and the prepared hole transport layer precursor solution is dropped onto the substrate 1, and the hole transport layer precursor solution is coated at a third speed for a third time, wherein the third speed is 3000-4000 rpm, and the third time is 30-40s. The third speed and the third time are selected according to actual needs, and no specific requirements are made here.

[0051] The substrate 1 coated with the hole transport layer precursor solution is placed on a heating plate for annealing. The annealing temperature is 90-110° C. and the annealing time is 10-15 min. The annealing temperature and annealing time are selected according to actual needs and no specific requirements are given here.

[0052] After the perovskite layer 4 is prepared, the electron transport layer 5 , the passivation layer 6 and the metal electrode 7 are prepared in sequence.

[0053] When preparing the electron transport layer 5, the electron transport layer 5 is formed on the perovskite film by evaporation. The material of the electron transport layer 5 is C60. Heating evaporation is performed on a vacuum evaporation device to evaporate the material of the electron transport layer 5 onto the perovskite film to form the electron transport layer 5. The thickness of the electron transport layer 5 is 200-250nm.

[0054] When preparing the passivation layer 6, the passivation layer 6 is formed on the electron transport layer 5 by evaporation. The material of the passivation layer 6 is BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline). Heating evaporation is performed on a vacuum evaporation device to evaporate the passivation layer 6 material onto the electron transport layer 5 to form the passivation layer 6. The thickness of the passivation layer 6 is 5-10nm.

[0055] When preparing the metal electrode 7, the metal electrode 7 is formed on the passivation layer 6 by evaporation. The metal electrode 7 is Au. The metal Au is evaporated onto the passivation layer 6 on a vacuum evaporation device to form the metal electrode 7. The thickness of the metal electrode 7 is 80-100nm.

[0056] A perovskite solar cell is prepared by the above-mentioned method for preparing a perovskite solar cell, wherein the perovskite layer 4 of the perovskite solar cell is doped with a dopant, and the dopant includes 4-bromo-3-trifluoromethoxybenzonitrile.

[0057] The perovskite solar cell comprises a substrate 1, an ITO conductive layer 2 arranged on the substrate 1, a hole transport layer 3 arranged on the ITO conductive layer 2, a perovskite layer 4 arranged on the hole transport layer 3, an electron transport layer 5 arranged on the perovskite layer 4, a passivation layer 6 arranged on the electron transport layer 5, and a metal electrode 7 arranged on the passivation layer 6, that is, on one side of the substrate 1, the ITO conductive layer 2, the hole transport layer 3, the perovskite layer 4, the electron transport layer 5, the passivation layer 6 and the metal electrode 7 are arranged in sequence, wherein the perovskite layer 4 is doped with a dopant, and the dopant is 4-bromo-3-trifluoromethoxybenzonitrile.

[0058] The following describes in detail some embodiments.

[0059] Embodiment 1

[0060] A method for preparing a perovskite solar cell comprises the following steps:

[0061] A substrate 1 is provided, and etching and cleaning treatments are performed on the substrate 1 in sequence: a glass substrate 1 with a highly transparent conductive layer of indium tin oxide (ITO) is etched into a desired pattern using a laser etcher;

[0062] After etching is completed, dust and other impurities on the surface of the substrate 1 are wiped off with a dust-free cloth and deionized water to perform the first cleaning process;

[0063] The glass substrate 1 is placed in deionized water, ethanol and isopropanol in turn for ultrasonic cleaning, and the ultrasonic cleaning time is 30 minutes each, and a second cleaning treatment is performed;

[0064] After the second cleaning treatment, in order to remove the organic impurities remaining on the surface, an ultraviolet ozone cleaning machine was used for 30 minutes to obtain a clean glass substrate 1.

[0065] Preparation of hole transport layer 3: Weigh 1 mg of MeO-2PACz and dissolve it in 2 mL of ethanol to prepare a hole transport layer precursor solution with a concentration of 0.5 mg / mL;

[0066] The prepared hole transport layer precursor solution was dropwise added and spin-coated on the clean ITO conductive layer 2 by spin coating, the spin coating speed was 3000 rpm, and the spin coating time was 30 s. After the spin coating was completed, the substrate 1 coated with the hole transport layer precursor solution was immediately placed on a heating plate for annealing, the annealing temperature was 100° C., and the annealing time was 10 min, to obtain a hole transport layer 3.

[0067] The preparation of the perovskite layer 4 comprises the following steps:

[0068] Prepare the first solution: weigh 65.1 mg of CsI, 818.4 mg of FAI and 2310 mg of PbI2, dissolve CsI, FAI and PbI2 in a first mixed solution of 2.4 mL of DMF and 0.6 mL of DMSO to form a first solution;

[0069] Prepare the second solution: weigh 187 mg of MABr and 612.9 mg of PbBr2, dissolve MABr and PbBr2 in 0.8 mL of DMF and 0.2 mL of DMSO second mixed solution to form a second solution;

[0070] 2.85 mL of the first solution and 0.15 mL of the second solution were measured and mixed, and 33 mg of MACl solid was added and dissolved to prepare a perovskite precursor solution;

[0071] The dopant 4-bromo-3-trifluoromethoxybenzonitrile is added to the prepared perovskite precursor solution at a ratio of 0.3% relative to the molar number of PbI2 in the perovskite precursor solution to obtain a perovskite precursor solution doped with 4-bromo-3-trifluoromethoxybenzonitrile.

[0072] Under a nitrogen environment, the above-mentioned perovskite precursor solution doped with 4-bromo-3-trifluoromethoxybenzonitrile is dropped on the substrate 1 of the prepared hole transport layer 3 for spin coating, the spin coating speed is 1000 rpm, the spin coating time is 10 s, after the first spin coating is completed, the second spin coating is performed, the second spin coating speed is 5000 rpm, the spin coating time is 30 s, in the last 5 s of the second spin coating, 1 mL of anisole is added as an anti-solvent to precipitate perovskite crystals, after the second spin coating is completed, the substrate 1 coated with the perovskite precursor solution is immediately transferred to a heating plate for annealing, the annealing temperature is 105 ° C, the annealing time is 10 min, to obtain a perovskite film, i.e., a perovskite layer 4.

[0073] Preparation of electron transport layer 5: heating and evaporating the material C60 of electron transport layer 5 onto the prepared perovskite film on a vacuum evaporation device to form electron transport layer 5. The thickness of electron transport layer 5 is 200 nm.

[0074] Preparation of the passivation layer 6: The material of the passivation layer 6, BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline), is evaporated onto the electron transport layer 5 on a vacuum evaporation device to form the passivation layer 6. The thickness of the passivation layer 6 is 5 nm.

[0075] Preparation of metal electrode 7: Au is evaporated onto the surface of passivation layer 6 on a vacuum evaporation device to form metal electrode 7. The thickness of metal electrode 7 is 80 nm.

[0076] A perovskite solar cell is prepared by the above-mentioned method for preparing a perovskite solar cell, wherein the perovskite layer 4 of the perovskite solar cell is doped with 4-bromo-3-trifluoromethoxybenzonitrile.

[0077] Embodiment 2

[0078] The difference between this embodiment and the first embodiment is that the doping ratio of the dopant 4-bromo-3-trifluoromethoxybenzonitrile is different, and the other process steps are the same and will not be repeated here.

[0079] In this embodiment, in the process of preparing the perovskite layer 4, the dopant 4-bromo-3-trifluoromethoxybenzonitrile is added to the prepared perovskite precursor solution at a ratio of 0.4% relative to the molar number of PbI2 to prepare the perovskite layer 4.

[0080] Embodiment 3

[0081] The difference between this embodiment and the first and second embodiments is that the doping ratio of the dopant 4-bromo-3-trifluoromethoxybenzonitrile is different, and the other process steps are the same and will not be repeated here.

[0082] In this embodiment, in the process of preparing the perovskite layer 4, the dopant 4-bromo-3-trifluoromethoxybenzonitrile is added to the prepared perovskite precursor solution at a ratio of 0.5% relative to the molar number of PbI2 to prepare the perovskite layer 4.

[0083] Embodiment 4

[0084] Compared with Example 1, Example 2 and Example 3, the difference between this embodiment is that the doping ratio of the dopant 4-bromo-3-trifluoromethoxybenzonitrile is different, and the other process steps are the same and will not be repeated here.

[0085] In this embodiment, in the process of preparing the perovskite layer 4, the dopant 4-bromo-3-trifluoromethoxybenzonitrile is added to the prepared perovskite precursor solution at a ratio of 0.6% relative to the molar number of PbI2 to prepare the perovskite layer 4.

[0086] Embodiment 5

[0087] Compared with Example 1, Example 2, Example 3 and Example 4, the difference between this embodiment is that the doping ratio of the dopant 4-bromo-3-trifluoromethoxybenzonitrile is different, and the other process steps are the same and will not be repeated here.

[0088] In this embodiment, in the process of preparing the perovskite layer 4, the dopant 4-bromo-3-trifluoromethoxybenzonitrile is added to the prepared perovskite precursor solution at a ratio of 0.8% relative to the molar number of PbI2 to prepare the perovskite layer 4.

[0089] Embodiment 6

[0090] Compared with Example 1, Example 2, Example 3, Example 4 and Example 5, the difference between this embodiment is that the doping ratio of the dopant 4-bromo-3-trifluoromethoxybenzonitrile is different, and the other process steps are the same and will not be repeated here.

[0091] In this embodiment, in the process of preparing the perovskite layer 4, the dopant 4-bromo-3-trifluoromethoxybenzonitrile is added to the prepared perovskite precursor solution at a ratio of 0.9% relative to the molar number of PbI2 to prepare the perovskite layer 4.

[0092] When the perovskite solar cells prepared in the above six embodiments were tested for cell performance, the volt-ampere characteristic curves of the solar cell devices were tested on a solar simulator equipped with a Keithley 2400 source meter and a 300W collimated xenon lamp (Newport). Before the test, the light intensity needed to be calibrated to 100 mW / cm2 using a standard silicon solar cell under simulated AM 1.5G illumination. 2 .

[0093] The doped perovskite solar cells and undoped perovskite cells prepared in the above six embodiments were respectively subjected to photoelectric conversion capacity tests, water stability tests, thermal stability tests and light stability tests, wherein the undoped perovskite cells were used as a control group, and the perovskite solar cells prepared in the six embodiments were used as an experimental group.

[0094] 1. Test the photoelectric conversion capability of the battery

[0095] In AM1.5G 100mW·cm -2 Under simulated sunlight conditions, doped and undoped perovskite solar cell devices (active area 0.1 cm 2 ) to test the battery efficiency, and the test results are shown in Table 1. Among them, V OC is the open circuit voltage of the battery device, J SC is the short-circuit current density of the battery device, FF is the fill factor of the battery device, and PCE is the photoelectric conversion efficiency of the battery.

[0096] Table 1 Battery photoelectric conversion capacity test data

[0097]

[0098] It can be seen from the contents of Table 1 that the efficiency of batteries with various doping concentrations is significantly improved compared to undoped batteries.

[0099] 2. Test the water stability of the battery

[0100] The doped and undoped battery devices were placed in a dark environment with a relative humidity of 75% at room temperature, and the battery efficiency was continuously tracked. The water stability of each group of batteries in a humid environment was tested. The test data is shown in Table 2. After the doped battery device was placed in this environment for 3000 hours, the doped battery device still maintained an initial efficiency of more than 90%. At this time, the efficiency of the undoped battery device was severely attenuated compared to the doped device, and the water stability of the battery was significantly and effectively improved.

[0101] Table 2 Water stability test data of batteries

[0102]

[0103] 3. Test the thermal stability of the battery

[0104] The doped and undoped battery devices were placed in an 85°C oven to test thermal stability. The test data is shown in Table 3. After being placed for 1500 hours, the doped battery still maintained more than 80% of its initial efficiency, while the control group only had 59.3% of its initial efficiency. The thermal stability of the doped battery device was significantly improved.

[0105] Table 3 Battery thermal stability test data

[0106]

[0107] 4. Test the light stability of the battery

[0108] The doped and undoped battery devices were placed in a nitrogen environment, and the efficiency stability of the doped and undoped battery devices was tested under simulated sunlight AM1.5G. The test data is shown in Table 4. After 1000 hours of continuous irradiation, the doped device can still maintain a good initial efficiency, while the efficiency of the control group device has been severely attenuated. The light stability of the doped battery device is improved.

[0109] Table 4 Light stability test data of batteries

[0110]

[0111] In summary, the perovskite layer is prepared by using a perovskite precursor solution doped with a dopant, so that the efficiency of the prepared perovskite solar cell is improved and the stability of the cell efficiency under water, thermal and light conditions is improved.

[0112] Due to the adoption of the above technical solution, in the process of preparing perovskite solar cells, when preparing the perovskite layer, a dopant is added to the configured perovskite precursor solution. The dopant can be 4-bromo-3-trifluoromethoxybenzonitrile, which is added to the configured perovskite precursor solution in a certain proportion. The dopant serves as a defect passivator of the perovskite layer in the perovskite solar cell, fills (passivates) the defects at the perovskite grain boundaries, and improves the photoelectric conversion efficiency of the cell; the passivation effect of the passivator on the defects at the perovskite grain boundaries is utilized to inhibit the adverse effects of water, heat and light on the perovskite solar cell, and enhance the stability of the cell efficiency in water, heat and light environments.

[0113] The embodiments of the present invention are described in detail above, but the contents described are only preferred embodiments of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that: In the step of preparing the perovskite layer, a dopant is added to the prepared perovskite precursor solution so that the prepared perovskite layer is doped with the dopant, wherein the dopant includes 4-bromo-3-trifluoromethoxybenzonitrile; The perovskite layer preparation comprises the following steps: In a first gas environment, a perovskite precursor solution doped with a dopant is applied to a substrate provided with a hole transport layer by spin coating; the first gas is nitrogen; when spin coating, a first spin coating and a second spin coating are performed in sequence, and an anti-solvent is added before the second spin coating is completed, so that perovskite crystals are precipitated; Annealing treatment is performed to obtain a perovskite layer.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The dopant is added to the prepared perovskite precursor solution in a certain ratio relative to the molar number of PbI2.

3. The method for preparing a perovskite solar cell according to claim 2, characterized in that: The ratio is 0.1%-1.0%.

4. The method for preparing a perovskite solar cell according to claim 3, characterized in that: The ratio is 0.3%-0.6%.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that: The perovskite precursor solution preparation step includes: adding CsI, FAI and PbI2 into a mixed solution of DMF and DMSO to prepare a first solution, adding MABr and PbBr2 into a mixed solution of DMF and DMSO to prepare a second solution, and mixing the first solution with the second solution to obtain a perovskite precursor solution.

6. The method for preparing a perovskite solar cell according to claim 5, characterized in that: The chemical formula of the perovskite precursor solution is MA 0.05 (Cs 0.05 FA 0.95 ) 0.95 Pb(I 0.95 Br 0.05 )3.

7. The method for preparing a perovskite solar cell according to any one of claims 1 to 6, characterized in that: Before preparing the perovskite layer, the method further includes preparing a substrate with a hole transport layer; After the perovskite layer is prepared, the electron transport layer, passivation layer and metal electrode are prepared in sequence.

8. A perovskite solar cell, characterized in that: The perovskite solar cell is prepared by the preparation method of any one of claims 1 to 7, wherein the perovskite layer of the perovskite solar cell is doped with a dopant, and the dopant includes 4-bromo-3-trifluoromethoxybenzonitrile.

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