Tin-lead perovskite solar cell preparation method and tin-lead perovskite solar cell

Abstract

According to the tin-lead perovskite solar cell preparation method and the tin-lead perovskite solar cell provided by the invention, in the process of preparing a perovskite layer, a dopant is added into a prepared perovskite precursor solution, so that the prepared perovskite layer contains the dopant; the doping agent comprises 2-thiophenecarboxamide, 2-thiopheneethylamine or 2-thiopheneacetamide. The method has the beneficial effects that the oxidation degree of divalent tin in the precursor solution is inhibited, the oxidation resistance of the perovskite thin film is improved, the defect density in the perovskite thin film is reduced, the dopant has good hydrophobicity and can be anchored on the surface of a perovskite crystal lattice, damage of water molecules to the perovskite thin film is prevented, and the perovskite thin film is prepared. And the cell photoelectric conversion efficiency and the device stability are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of solar cells, and in particular relates to a method for preparing a tin-lead perovskite solar cell and a tin-lead perovskite solar cell. Background Art

[0002] Thanks to the long carrier diffusion length, adjustable band gap, high absorption coefficient and low preparation cost, the photoelectric conversion efficiency of perovskite solar cells has achieved very rapid development since its birth in the laboratory. The highest efficiency of tin-lead mixed perovskite solar cells reported recently has exceeded 23%. However, in the process of preparing thin film solutions by solvent method and heating annealing, divalent tin will be oxidized to tetravalent tin, forming a large number of tin vacancies, and a large number of iodine vacancies will be generated at the grain boundaries, causing deep energy level defects, making it easy for photogenerated carriers to be captured, resulting in non-radiative recombination, hindering the extraction and transmission of carriers. Ion vacancies can also cause other ions to migrate and accelerate the degradation of perovskite films, seriously affecting the efficiency and stability of perovskite solar cells. Therefore, the development of corresponding dopants that can inhibit oxidation and passivate perovskite surface defects can effectively solve the above problems.

[0003] The strategies for inhibiting the oxidation of divalent tin and passivating defects in the prior art include: directly adding metal and ammonium halides to the perovskite precursor to form hydrogen bonds, ionic bonds, or releasing the perovskite lattice stress to reduce the generation of ion vacancies or inhibit oxidation, or passivating by generating two-dimensional perovskites. These strategies mainly focus on a single effect, cannot have dual effects at the same time, and are used in low amounts, and require too high a precision for the doping dose. To solve these problems, the ideal passivation strategy is to use an organic passivator with a strong coordination effect and a high content of molecules that will not have a significant effect on the film quality and battery efficiency stability. On the basis of inhibiting the oxidation of divalent tin, the perovskite lattice defects are passivated, and the doping amount will not have a significant effect on the performance.

[0004] Existing dopant molecules have single functions, such as passivation function, antioxidant function, hydrophobic function, etc., or a combination of two, and cannot have three or more functions at the same time; existing dopants have high requirements for content, and a small doping content can effectively play an improvement role, and there are high requirements for content accuracy. The deviation of the content of the two groups of experiments will seriously affect the performance improvement; dopants are relatively expensive and have high purity requirements. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for preparing a tin-lead perovskite solar cell and a tin-lead 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 tin-lead 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 contains a dopant, and the dopant includes 2-thiophenecarboxamide (TPCA), 2-thiopheneethylamine (TPEA) or 2-thiopheneacetamide (TPTA).

[0007] Further, the dopant is added to the prepared perovskite precursor solution at a certain molar percentage relative to the perovskite precursor solution.

[0008] Further, the mole percentage is 1-3%.

[0009] Furthermore, the perovskite precursor solution preparation step includes: FAI, MAI, PbI 2 SnI 2 、SnF 2 and MACl were added into a mixed solution of DMF and DMSO to obtain a perovskite precursor solution.

[0010] Furthermore, the chemical formula of the perovskite precursor solution is FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 I 3 .

[0011] Further, the preparation of the perovskite layer includes the following steps:

[0012] Spin coating a perovskite precursor solution doped with a dopant onto a glass substrate provided with a hole transport layer;

[0013] Annealing treatment is performed to obtain a perovskite layer.

[0014] Furthermore, the preparation of the glass substrate provided with a hole transport layer comprises the following steps:

[0015] The PEDOT:PSS aqueous solution was coated on the glass substrate by spin coating;

[0016] A first annealing treatment is performed to obtain a glass substrate provided with a hole transport layer.

[0017] Furthermore, after the perovskite layer is prepared, the electron transport layer, the passivation layer and the metal electrode are prepared in sequence.

[0018] Furthermore, the electron transport layer and the passivation layer are prepared by vacuum evaporation.

[0019] A tin-lead perovskite solar cell is prepared by the tin-lead perovskite solar cell preparation method as described above, wherein the perovskite layer of the tin-lead perovskite solar cell is doped with a dopant, and the dopant includes 2-thiophenecarboxamide (TPCA), 2-thiopheneethylamine (TPEA) or 2-thiopheneacetamide (TPTA).

[0020] Due to the adoption of the above technical scheme, in the process of preparing perovskite solar cells, in the process of preparing perovskite solar cells, and in the process of preparing perovskite layers, a dopant is added to a configured perovskite precursor solution, the dopant is a thiophene-based organic small molecule, which can be 2-thiophenecarboxamide (TPCA), 2-thiopheneethylamine (TPEA) or 2-thiopheneacetamide (TPTA), the dopant is added to the configured perovskite precursor solution in a certain proportion, and the thiophene S and amide O or amino N of the dopant are combined with uncoordinated lead and tin ions to inhibit the degree of oxidation of divalent tin in the precursor solution, improve the antioxidant properties of the perovskite film, and reduce the defect density in the perovskite film. The dopant has good hydrophobicity and can be anchored on the surface of the perovskite lattice to prevent water molecules from damaging the perovskite film, thereby improving the photoelectric conversion efficiency of the battery and the stability of the device. The dopant has low requirements on the doping amount and purity, is cheap, and will not seriously damage the device performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of a tin-lead perovskite solar cell according to an embodiment of the present invention;

[0022] Figure 2a is an ESP distribution diagram of 2-thiopheneacetamide (TPTA) according to an embodiment of the present invention;

[0023] Figure 2b is an ESP distribution diagram of 2-thiophenecarboxamide (TPCA) according to an embodiment of the present invention;

[0024] Figure 2c is an ESP distribution diagram of 2-thiopheneethylamine (TPEA) according to one embodiment of the present invention;

[0025] Figure 3a The Pb element XPS spectra of an undoped perovskite film and a perovskite film doped with 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA), and 2-thiopheneethylamine (TPEA) according to an embodiment of the present invention;

[0026] Figure 3b The Sn element XPS spectra of the undoped perovskite film and the perovskite film doped with 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA), and 2-thiopheneethylamine (TPEA) according to one embodiment of the present invention;

[0027] Figure 4a It is a PCE efficiency statistical diagram of an undoped battery device and a battery device doped with 2-thiopheneacetamide (TPTA) at different doping ratios according to an embodiment of the present invention;

[0028] Figure 4b V of an undoped battery device and a battery device doped with 2-thiopheneacetamide (TPTA) at different doping ratios according to an embodiment of the present invention OC Efficiency statistics chart;

[0029] Figure 4c It is a PCE efficiency statistical diagram of an undoped battery device and a battery device doped with 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA), and 2-thiopheneethylamine (TPEA) according to an embodiment of the present invention (the doping ratio of 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA), and 2-thiopheneethylamine (TPEA) is 2%);

[0030] Figure 4d V of an undoped battery device and a battery device doped with 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA), or 2-thiopheneethylamine (TPEA) according to an embodiment of the present invention OC Efficiency statistics (the doping ratio of 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA), and 2-thiopheneethylamine (TPEA) is 2%);

[0031] Figure 5a is a contact angle diagram of an undoped perovskite film according to an embodiment of the present invention;

[0032] Figure 5b is a contact angle diagram of a perovskite film doped with 2-thiopheneacetamide (TPTA) according to an embodiment of the present invention;

[0033] Figure 5c is a contact angle diagram of a perovskite film doped with 2-thiophenecarboxamide (TPCA) according to an embodiment of the present invention;

[0034] Figure 5d is a contact angle diagram of a perovskite film doped with 2-thiopheneethylamine (TPEA) according to an embodiment of the present invention;

[0035] Figure 6 Sn in the undoped and doped perovskite film modified with 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA), and 2-thiopheneethylamine (TPEA) according to one embodiment of the present invention 2+ and Sn 4+ Content distribution diagram.

[0036] In the figure:

[0037] 1. Glass substrate 2. Conductive layer 3. Hole transport layer

[0038] 4. Perovskite layer 5. Electron transport layer 6. Passivation layer

[0039] 7. Metal Electrode DETAILED DESCRIPTION

[0040] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0041] Figure 1 A schematic structural diagram of a tin-lead perovskite solar cell according to an embodiment of the present invention is shown. This embodiment relates to a method for preparing a tin-lead perovskite solar cell and a tin-lead perovskite solar cell. When preparing the tin-lead perovskite solar cell, a dopant is added to a configured perovskite precursor solution. The dopant is a thiophene-based organic small molecule, which effectively inhibits the degree of oxidation of divalent tin in the precursor solution, reduces the defect density in the perovskite film, and meets the three requirements of passivation, anti-oxidation and hydrophobicity for improving battery efficiency and stability.

[0042] A method for preparing a tin-lead perovskite solar cell, such as Figure 1 As shown, in the process of 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 layer 4 contains a dopant. The dopant can be used as a defect passivator of the perovskite layer 4 in the tin-lead perovskite solar cell, passivates the defects of the perovskite layer 4, reduces the defect density in the perovskite film, has antioxidant properties, effectively inhibits the degree of oxidation of divalent tin in the precursor solution, has hydrophobicity, prevents water molecules from damaging the perovskite film, and effectively improves the cell photoelectric conversion efficiency and device stability.

[0043] In some feasible embodiments, the above-mentioned dopant includes 2-thiophenecarboxamide (TPCA), 2-thiopheneethylamine (TPEA) or 2-thiopheneacetamide (TPTA), that is, the dopant is a thiophene-based organic small molecule, and the thiophene S and amide O or amino N of the dopant are combined with uncoordinated lead and tin ions to effectively inhibit the degree of oxidation of divalent tin in the precursor solution and reduce the defect density in the perovskite film. At the same time, the dopant itself has good hydrophobicity and can be anchored on the surface of the perovskite lattice, effectively preventing water molecules from destroying the perovskite film, and improving the hydrophobicity of the perovskite film, so that the modified tin-lead perovskite solar cell device has a significant improvement in stability. The dopant has low requirements on the doping amount, low purity requirements, and low price. Compared with dopants that require a higher doping amount, it will not seriously damage the performance of the tin-lead perovskite solar cell device.

[0044] When the above-mentioned dopant is added, the dopant is added to the configured perovskite precursor solution at a certain molar percentage relative to the perovskite precursor solution, and the molar percentage is 1-3%. The molar percentage can be any ratio value between 1-3%, such as 1%, 2%, 3%, etc., which is selected according to actual needs, and no specific requirements are made here.

[0045] After the dopant is added into the perovskite precursor solution, the perovskite precursor solution doped with the dopant is used to prepare the perovskite layer 4 .

[0046] The above-mentioned steps of preparing the perovskite precursor solution include: mixing FAI, MAI, PbI 2 SnI 2 、SnF 2 and MACl are added to a mixed solution of DMF and DMSO to obtain a perovskite precursor solution. The chemical formula of the perovskite precursor solution is FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 I 3 .

[0047] In some feasible embodiments, preferably, the concentration of added MACl is 0.1% to obtain higher device efficiency.

[0048] After the perovskite precursor solution is prepared, a dopant is added to the perovskite precursor solution, and the dopant is added to the prepared perovskite precursor solution at a certain molar percentage relative to the perovskite precursor solution to obtain a perovskite precursor solution doped with the dopant, and the molar percentage is 1-3%. After the dopant is added to the perovskite precursor solution, it is stirred for a certain period of time, and after the stirring is completed, it is dropped onto the glass substrate 1 provided with the hole transport layer 3, and is coated by spin coating to prepare the perovskite layer 4, and the stirring time is 2-4h.

[0049] After the perovskite precursor solution doped with the dopant is prepared, the perovskite layer 4 is prepared. The preparation of the perovskite layer 4 includes the following steps:

[0050] Spin coating is performed on a glass substrate 1 provided with a hole transport layer 3 by applying a dopant-doped perovskite precursor solution. In this step, the dopant-doped perovskite precursor solution is added dropwise to the prepared glass substrate 1 with the hole transport layer 3 after being stirred for a certain period of time, and the dopant-doped perovskite precursor solution is applied to the hole transport layer 3 by spin coating. During the spin coating, the first spin coating and the second spin coating are performed in sequence, and an anti-solvent is added dropwise before the second spin coating is completed, so that perovskite crystals are precipitated.

[0051] During the first spin coating, the spin coating is performed at a first rotation speed and for a first time;

[0052] During the second spin coating, the spin coating is performed at a second rotation speed and for a second time to complete the coating of the perovskite precursor solution doped with the dopant;

[0053] Among them, the first speed is 500-1500r / min, the first time is 5-15s, the second speed is 3000-5000r / min, and the second time is 30-50s. The first speed, first time, second speed and second time are selected according to actual needs, and no specific requirements are made here.

[0054] 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 the second speed, an anti-solvent is added within a third time before the spin coating is completed to allow the perovskite crystals to precipitate. The third time is 10-20s. The third time is selected according to actual needs and no specific requirements are made here.

[0055] In some feasible embodiments, the anti-solvent can be anisole, chlorobenzene or ethyl acetate, preferably chlorobenzene. The added volume of the anti-solvent is 100-200 μL. The added volume of the anti-solvent is selected according to actual needs and no specific requirements are made here.

[0056] Annealing treatment is performed to obtain a perovskite layer 4, which is formed on the hole transport layer 3: In this step, the glass substrate 1 provided with the hole transport layer 3 and coated with the perovskite precursor solution doped with a dopant is placed on a hot table for annealing. The annealing temperature is 80-120°C and the annealing time is 5-15 minutes. The annealing temperature and annealing time are selected according to actual needs and no specific requirements are made here.

[0057] The preparation of the substrate provided with the hole transport layer 3 comprises the following steps:

[0058] A glass substrate 1 is provided, and the glass substrate 1 is cleaned to improve the cleanliness of the glass substrate 1: the glass substrate 1 may be a glass substrate 1 having a highly transparent conductive layer 2 of indium-doped tin oxide (ITO), or the glass substrate 1 may be a glass substrate 1 having a highly transparent conductive layer 2 of fluorine-doped tin oxide (FTO), and the selection is made according to actual needs;

[0059] Cleaning the glass substrate 1: Cleaning the glass substrate 1, placing the cleaned glass substrate 1 in an ultraviolet-ozone cleaning apparatus for cleaning for 20-40 minutes, to remove organic impurities remaining on the surface of the glass substrate 1;

[0060] Providing a PEDOT:PSS aqueous solution, filtering the PEDOT:PSS aqueous solution using a filter membrane, in some feasible embodiments, the filter membrane is preferably a 0.22 μm filter membrane, and coating the filtered PEDOT:PSS aqueous solution on a glass substrate 1 to prepare a hole transport layer 3;

[0061] When the PEDOT:PSS aqueous solution is coated on the glass substrate 1, the PEDOT:PSS aqueous solution is coated on the glass substrate 1 by spin coating. After the coating of the PEDOT:PSS aqueous solution is completed, the first annealing treatment is performed to obtain a glass substrate 1 provided with a hole transport layer 3. Specifically, when the PEDOT:PSS aqueous solution is coated on the glass substrate 1, it is spin-coated at a third speed and a fourth time. The third speed is 3000-5000r / min, and the fourth time is 20-40s. The third speed and the fourth time are selected according to actual needs, and no specific requirements are made here. When the PEDOT:PSS aqueous solution is coated, the added volume of the PEDOT:PSS aqueous solution is 30-50μL. The added volume of the PEDOT:PSS aqueous solution is selected according to actual needs, and no specific requirements are made here.

[0062] After the PEDOT:PSS aqueous solution is coated, the glass substrate 1 is subjected to a first annealing treatment. During the first annealing treatment, the first annealing temperature is greater than 100°C, and the first annealing time is greater than 10 minutes. In some feasible embodiments, preferably, the first annealing temperature is 150°C, and the first annealing time is 20 minutes.

[0063] After the first annealing treatment is completed, the glass substrate 1 is placed in a glove box and cooled at a temperature of 20-30° C. for 20-40 min to prepare a hole transport layer 3 on the glass substrate 1 .

[0064] 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.

[0065] When preparing the electron transport layer 5, a vacuum evaporation method is used to form the electron transport layer 5 on the perovskite film. The material of the electron transport layer 5 is C60, and heating evaporation is performed on a high-temperature evaporation coating device. The evaporation rate is The material C60 of the electron transport layer 5 is evaporated onto the perovskite film to form the electron transport layer 5 , and the thickness of the electron transport layer 5 is 10-30 nm.

[0066] When preparing the passivation layer 6, a vacuum evaporation method is used to form the passivation layer 6 on the electron transport layer 5. The material of the passivation layer 6 is BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline). BCP, as a hole blocking material, can effectively block holes and improve the performance of the perovskite battery. The heating evaporation is performed on a high-temperature evaporation coating device at a evaporation rate of The material of the passivation layer 6 is evaporated onto the electron transport layer 5 to form the passivation layer 6 . The thickness of the passivation layer 6 is 5-10 nm.

[0067] When preparing the metal electrode 7, the metal electrode 7 is formed on the passivation layer 6 by evaporation. The metal electrode 7 is Ag. Metal Ag 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 70-90nm.

[0068] A tin-lead perovskite solar cell is prepared by the tin-lead perovskite solar cell preparation method as described above, wherein the perovskite layer 4 of the tin-lead perovskite solar cell is doped with a dopant, and the dopant includes 2-thiophenecarboxamide, 2-thiopheneethylamine or 2-thiopheneacetamide.

[0069] like Figure 1As shown, the tin-lead perovskite solar cell includes a glass substrate 1, a hole transport layer 3 arranged on the glass substrate 1, 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, a conductive layer 2 is arranged on one side of the glass substrate 1, and the conductive layer 2 can be an ITO conductive layer or a FTO conductive layer. The hole transport layer 3, the perovskite layer 4, the electron transport layer 5, the passivation layer 6 and the metal electrode 7 are sequentially arranged on the conductive layer 2, wherein the perovskite layer 4 is doped with a dopant, and the dopant includes 2-thiophenecarboxamide, 2-thiopheneethylamine or 2-thiopheneacetamide.

[0070] The following describes in detail some embodiments.

[0071] Embodiment 1

[0072] A method for preparing a tin-lead perovskite solar cell comprises the following steps:

[0073] A glass substrate 1 is provided, and the glass substrate 1 is cleaned to improve the cleanliness of the glass substrate 1: the glass substrate 1 is a glass substrate 1 having a high transparent conductive layer 2 of fluorine-doped tin oxide (FTO);

[0074] Cleaning the glass substrate 1: Cleaning the glass substrate 1, placing the cleaned glass substrate 1 in an ultraviolet-ozone cleaning apparatus for cleaning for 30 minutes, to remove organic impurities remaining on the surface of the glass substrate 1;

[0075] A PEDOT:PSS aqueous solution is provided, the PEDOT:PSS aqueous solution is filtered using a 0.22 μm filter membrane, and the filtered PEDOT:PSS aqueous solution is coated on a glass substrate 1 to prepare a hole transport layer 3; when the PEDOT:PSS aqueous solution is coated on the substrate, the PEDOT:PSS aqueous solution is coated on the substrate by spin coating, the spin coating speed is 4000 r / min, the spin coating time is 30 s, and the added volume of the PEDOT:PSS aqueous solution is 40 μL;

[0076] After the PEDOT:PSS aqueous solution is coated, the glass substrate 1 is subjected to a first annealing treatment. During the first annealing treatment, the first annealing temperature is 150° C. and the first annealing time is 20 minutes.

[0077] After the first annealing treatment is completed, the glass substrate 1 is placed in a glove box and cooled at a temperature of 25° C. for 30 min to prepare a hole transport layer 3 on the glass substrate 1 .

[0078] The preparation of the perovskite layer 4 comprises the following steps:

[0079] Prepare the perovskite precursor solution: weigh 260.1 mg of FAI, 103.1 mg of MAI, and 497.9 mg of PbI 2 , 401.7 mg SnI 2 , 16.8 mg SnF 2 7.3 mg of MACl was dissolved in a mixed solvent of DMF and DMSO with a volume ratio of 3:1 to prepare a perovskite precursor solution.

[0080] The dopant 2-thiophenecarboxamide is added to the prepared perovskite precursor solution at a molar percentage of 1% relative to the perovskite precursor solution to obtain a perovskite precursor solution doped with 2-thiophenecarboxamide.

[0081] The above-mentioned perovskite precursor solution doped with 2-thiophenecarboxamide is dropped onto the prepared glass substrate 1 of the hole transport layer 3 for the first spin coating, the spin coating speed is 1000r / min, the spin coating time is 10s, after the first spin coating is completed, the second spin coating is performed, the second spin coating speed is 4000r / min, the spin coating time is 40s, at 15s after the start of the second spin coating, 150μL of chlorobenzene is added as an anti-solvent to precipitate perovskite crystals, after the second spin coating is completed, the substrate coated with the perovskite precursor solution is transferred to a hot stage for annealing, the annealing temperature is 100°C, and the annealing time is 10min, to obtain a perovskite film, i.e., the perovskite layer 4.

[0082] Preparation of electron transport layer 5: After the perovskite film is cooled to room temperature, the material C60 of the electron transport layer 5 is heated and evaporated onto the prepared perovskite film on a high-temperature evaporation coating apparatus to prepare the electron transport layer 5. The evaporation rate is maintained at The thickness of the electron transport layer 5 is 20 nm.

[0083] Preparation of the passivation layer 6: The material BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) of the passivation layer 6 is evaporated onto the electron transport layer 5 on a high temperature evaporation coating apparatus. After the electron transport layer 5 is prepared, the BCP organic source is turned on, and the evaporation rate is A passivation layer 6 is formed, and the thickness of the passivation layer 6 is 5 nm.

[0084] Preparation of metal electrode 7: Ag 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.

[0085] A tin-lead perovskite solar cell is prepared by the above-mentioned method for preparing a tin-lead perovskite solar cell, wherein a perovskite layer 4 of the tin-lead perovskite solar cell is doped with 2-thiophenecarboxamide, and the structure of the tin-lead perovskite solar cell is glass / FTO / PEDOT:PSS / perovskite layer / C60 / BCP / Ag.

[0086] Embodiment 2

[0087] The difference between this embodiment and the first embodiment is that the doping ratio of the dopant 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, the dopant 2-thiophenecarboxamide is added to the prepared perovskite precursor solution at a molar percentage of 2% relative to the perovskite precursor solution to prepare the perovskite layer 4 .

[0089] Embodiment 3

[0090] The difference between this embodiment and the first and second embodiments is that the doping ratio of the dopant 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, the dopant 2-thiophenecarboxamide is added to the prepared perovskite precursor solution at a molar percentage of 3% relative to the perovskite precursor solution to prepare the perovskite layer 4 .

[0092] Embodiment 4

[0093] The difference between this embodiment and the first embodiment is that the composition of the dopant is different, and the other process steps are the same and will not be repeated here.

[0094] In this embodiment, in the process of preparing the perovskite layer, the dopant 2-thiopheneethylamine is added to the prepared perovskite precursor solution at a molar percentage of 1% relative to the perovskite precursor solution to prepare the perovskite layer 4 .

[0095] Embodiment 5

[0096] The difference between this embodiment and the fourth embodiment is that the doping ratio of the dopant is different, and the other process steps are the same and will not be repeated here.

[0097] In this embodiment, in the process of preparing the perovskite layer, the dopant 2-thiopheneethylamine is added to the prepared perovskite precursor solution at a molar percentage of 2% relative to the perovskite precursor solution to prepare the perovskite layer 4 .

[0098] Embodiment 6

[0099] The difference between this embodiment and the fourth and fifth embodiments is that the doping ratio of the dopant is different, and the other process steps are the same and will not be repeated here.

[0100] In this embodiment, in the process of preparing the perovskite layer, the dopant 2-thiopheneethylamine is added to the prepared perovskite precursor solution at a molar percentage of 3% relative to the perovskite precursor solution to prepare the perovskite layer 4 .

[0101] Embodiment 7

[0102] The difference between this embodiment and the first embodiment is that the composition of the dopant is different, and the other process steps are the same and will not be repeated here.

[0103] In this embodiment, in the process of preparing the perovskite layer, the dopant 2-thiopheneacetamide is added to the prepared perovskite precursor solution at a molar percentage of 1% relative to the perovskite precursor solution to prepare the perovskite layer 4 .

[0104] Embodiment 8

[0105] The difference between this embodiment and the seventh embodiment is that the doping ratio of the dopant is different, and the other process steps are the same and will not be repeated here.

[0106] In this embodiment, in the process of preparing the perovskite layer, the dopant 2-thiopheneacetamide is added to the prepared perovskite precursor solution at a molar percentage of 2% relative to the perovskite precursor solution to prepare the perovskite layer 4 .

[0107] Embodiment 9

[0108] The difference between this embodiment and the seventh and eighth embodiments is that the doping ratio of the dopant is different, and the other process steps are the same and will not be repeated here.

[0109] In this embodiment, in the process of preparing the perovskite layer, the dopant 2-thiopheneacetamide is added to the prepared perovskite precursor solution at a molar percentage of 3% relative to the perovskite precursor solution to prepare the perovskite layer 4 .

[0110] The composition and doping ratio of the dopants in the above nine embodiments are summarized as shown in Table 1:

[0111] Table 1 Summary of dopant composition and doping ratio of nine examples

[0112]

[0113] The tin-lead perovskite solar cells prepared in the above nine embodiments were tested for cell performance using a solar simulator (aperture 40×40 cm) equipped with a Keithley 2400 source meter and a 300 W collimated xenon lamp (Newport). 2 ) Test the volt-ampere characteristic curve of solar cell devices. Before testing, the light intensity needs to be calibrated to 100mW·cm using a standard silicon solar cell under simulated AM1.5G light. -2 The tin-lead perovskite solar cells doped with dopants and the tin-lead perovskite solar cells not doped with dopants prepared in some embodiments were selected to test the electrostatic potential of the compounds, the interaction force with Pb and Sn ions, the enhancement of photoelectric capacity, the enhancement of water stability and the inhibition of oxidation, wherein the undoped tin-lead perovskite solar cells were used as the control group, and the tin-lead perovskite solar cells doped with dopants prepared in the above embodiments were used as the experimental group.

[0114] 1. Analysis of compound electrostatic potential

[0115] The compound electrostatic potential analysis test was performed on the tin-lead perovskite solar cell prepared by the preparation method of Example 2, the tin-lead perovskite solar cell prepared by the preparation method of Example 5, and the tin-lead perovskite solar cell prepared by the preparation method of Example 8. Figure 2a-2c As shown in the ESP diagram obtained by simulation calculation, it can be seen that 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA) and 2-thiopheneethylamine (TPEA) molecules all have a passivation effect on perovskite. The electrostatic potential of the amino group in the 2-thiopheneethylamine (TPEA) molecule is negative, indicating that it can react with Pb 2+ / Sn 2+ Coordination, passivation of Pb 2+ / Sn 2+ defects; 2-thiopheneacetamide (TPTA) and 2-thiophenecarboxamide (TPCA) have strong electron-withdrawing carbonyl groups, and their electronegativity is much higher than the amino group in 2-thiopheneethylamine (TPEA). Therefore, although the coordination force between 2-thiopheneethylamine (TPEA) and metal ions is relatively weaker than that of the other two, it also has a passivation effect on perovskite. 2-thiopheneacetamide (TPTA) and 2-thiophenecarboxamide (TPCA) molecules with the same amide passivation group, because the carbonyl group on the carboxamide of the 2-thiophenecarboxamide (TPCA) molecule will form a conjugate with the thiophene ring, weakening the electron-donating effect of the carbonyl group and thiophene S, and weakening its interaction with Pb 2+ / Sn 2+The coordination ability affects the passivation effect; while the acetamide on the 2-thiopheneacetamide (TPTA) molecule has no effect on the electron donation effect of the carbonyl and thiophene S because the ethyl group on the middle alkyl chain interrupts the conjugation effect of the carbonyl and thiophene ring, so that the carbonyl and thiophene S can jointly passivate the perovskite defects.

[0116] 2. The manifestation of the interaction with Pb and Sn ions

[0117] The tin-lead perovskite solar cell prepared by the preparation method of Example 2, the tin-lead perovskite solar cell prepared by the preparation method of Example 5, and the tin-lead perovskite solar cell prepared by the preparation method of Example 8 were tested for the interaction force analysis with Pb and Sn ions. Figure 3a-3b As shown in the XPS results, it can be seen that the Pb 4f orbital signal peak is split into Pb 4f 7 / 2 and Pb4f 5 / 2 The orbital energy level signals are located at 138.16 and 143.01 eV in the undoped perovskite. When 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA) and 2-thiopheneethylamine (TPEA) are doped in the perovskite, the Pb 4f orbital binding energy shifts to 137.99 and 142.81 eV, 138.09 and 142.96 eV and 138.00 and 142.87 eV in the low field, indicating that 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA) and 2-thiopheneethylamine (TPEA) can bind to Pb 2+ The interaction affects the orbital energy of Pb 4f, causing it to move downfield. At the same time, when fitting the peaks of Pb orbital signals, the common low binding energy Pb0 signal peak does not exist.

[0118] Similarly, in the XPS analysis of the Sn 3d orbital energy level signal peak, it was found that the Sn 3d was doped with 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA) and 2-thiopheneethylamine (TPEA). 5 / 2 The orbital binding energy also shifted from 486.55 eV to the high field 486.78 eV, 486.75 eV and 486.61 eV, respectively, shifting by ~0.23 eV, ~0.20 eV and ~0.06 eV, indicating that 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA) and 2-thiopheneethylamine (TPEA) can also bind to Sn. 2+ At the same time, when fitting the Sn orbital signal peak, there is no common low binding energy Sn0 signal peak.

[0119] 3. Demonstration of enhanced photoelectric capabilities

[0120] The tin-lead perovskite solar cell prepared by the preparation method of Example 1, the tin-lead perovskite solar cell prepared by the preparation method of Example 2, and the tin-lead perovskite solar cell prepared by the preparation method of Example 3 were tested for photoelectric capacity enhancement analysis. Figure 4a-4b As shown in the box plot, it can be seen that the PCE and V of the battery devices doped with 2-thiopheneacetamide (TPTA) at different doping ratios OC The average PCE of the undoped battery device was 17.18±0.34%, and the average V OC The average PCE of the device doped with 1% 2-thiopheneacetamide (TPTA) is 18.75±0.47%, and the average V OC The average PCE of the device doped with 2% 2-thiopheneacetamide (TPTA) is 19.28±0.83%, and the average V OC The average PCE of the device doped with 2-thiopheneacetamide (TPTA) with a doping ratio of 3% is 17.68±0.71%, and the average V OC is 0.8013±0.009V. Figure 4c-4d As shown, the PCE and V of the battery device doped with 2-thiophenecarboxamide (TPCA) OC The average PCE of the battery device doped with 2% 2-thiophenecarboxamide (TPCA) was 18.17±0.34%, and the average V OC The PCE and V of the battery device doped with 2-thiopheneethylamine (TPEA) are 0.8277±0.005 V. OC The average PCE of the battery device doped with 2% 2-thiopheneethylamine (TPEA) was 18.00±0.76%, and the average V OC It is 0.8072±0.013V.

[0121] Statistical results further confirmed that devices treated with 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA), and 2-thiopheneethylamine (TPEA) improved V OC , both can achieve higher PCE.

[0122] 4. The manifestation of enhanced water stability

[0123] The tin-lead perovskite solar cell prepared by the preparation method of Example 2, the tin-lead perovskite solar cell prepared by the preparation method of Example 5, and the tin-lead perovskite solar cell prepared by the preparation method of Example 8 were tested for water stability enhancement analysis. Figure 5a-5d As shown, compared with the undoped perovskite film (58.3°), the water contact angle of the perovskite film doped with 2-thiopheneacetamide (TPTA) is 72.8°, the water contact angle of the perovskite film doped with 2-thiophenecarboxamide (TPCA) is 70.3°, and the water contact angle of the perovskite film doped with 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA) and 2-thiopheneethylamine (TPEA) is 69°. The water contact angles of the perovskite films doped with 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA) and 2-thiopheneethylamine (TPEA) are significantly increased. A larger contact angle is beneficial to slowing down the penetration of water vapor into the perovskite material, thereby more effectively protecting the perovskite material and improving the air stability of the battery.

[0124] 5. On the manifestation of anti-oxidation effect

[0125] The tin-lead perovskite solar cell prepared by the preparation method of Example 2, the tin-lead perovskite solar cell prepared by the preparation method of Example 5, and the tin-lead perovskite solar cell prepared by the preparation method of Example 8 were tested for oxidation inhibition analysis. Figure 6 As shown, the Sn in the perovskite component 2+ Easily oxidized to Sn 4+ , generating vacancies and producing P-type doping, which is one of the main reasons for the low efficiency and poor stability of Sn-Pb perovskite devices. 2+ and Sn 4+ The content was tested and the test results are shown in Table 2.

[0126] Table 2 Sn in perovskite films modified with different dopants 2+ and Sn 4+ content

[0127]

[0128] It can be seen from Table 2 that the Sn content in the perovskite film after doping with 2-thiopheneacetamide (TPTA), 2-thiophenecarboxamide (TPCA) and 2-thiopheneethylamine (TPEA) is 4+ The content of the SnI in the precursor solution is significantly reduced compared with that of the undoped perovskite film, indicating that the 2-thiopheneacetamide (TPTA) molecules, 2-thiophenecarboxamide (TPCA) molecules and 2-thiopheneethylamine (TPEA) molecules are all 2 interaction, increasing the oxidation to Sn 4+ The energy required, Sn 4+ The reduction in Sn content reduces the Sn vacancy concentration, inhibits P-type doping, and is beneficial to improving device performance.

[0129] Due to the adoption of the above technical scheme, in the process of preparing perovskite solar cells, in the process of preparing perovskite solar cells, and in the process of preparing perovskite layers, a dopant is added to a configured perovskite precursor solution, the dopant is a thiophene-based organic small molecule, which may be 2-thiophenecarboxamide, 2-thiopheneethylamine or 2-thiopheneacetamide, the dopant is added to the configured perovskite precursor solution in a certain proportion, and the thiophene S and amide O or amino N of the dopant are combined with uncoordinated lead and tin ions to inhibit the degree of oxidation of divalent tin in the precursor solution, improve the antioxidant properties of the perovskite film, and reduce the defect density in the perovskite film. The dopant has good hydrophobicity and can be anchored on the surface of the perovskite lattice to prevent water molecules from damaging the perovskite film, thereby improving the photoelectric conversion efficiency of the battery and the stability of the device. The dopant has low requirements on the doping amount and purity, is cheap, and will not seriously damage the device performance.

[0130] 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 tin-lead perovskite solar cell, characterized in that: In the process of preparing the perovskite layer, a dopant is added to the prepared perovskite precursor solution so that the prepared perovskite layer contains the dopant, and the dopant includes 2-thiophenecarboxamide, 2-thiopheneethylamine or 2-thiopheneacetamide.

2. The method for preparing a tin-lead perovskite solar cell according to claim 1, characterized in that: The dopant is added to the prepared perovskite precursor solution at a certain molar percentage relative to the perovskite precursor solution.

3. The method for preparing a tin-lead perovskite solar cell according to claim 2, characterized in that: The molar percentage is 1-3%.

4. The method for preparing a tin-lead perovskite solar cell according to any one of claims 1 to 3, characterized in that: The step of preparing the perovskite precursor solution comprises: adding FAI, MAI, PbI2, SnI2, SnF2 and MACl into a mixed solution of DMF and DMSO to obtain a perovskite precursor solution.

5. The method for preparing a tin-lead perovskite solar cell according to claim 4, characterized in that: The chemical formula of the perovskite precursor solution is FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3.

6. The method for preparing a tin-lead perovskite solar cell according to claim 4, characterized in that: The perovskite layer preparation comprises the following steps: Spin coating a perovskite precursor solution doped with a dopant onto a glass substrate provided with a hole transport layer; Annealing treatment is performed to obtain a perovskite layer.

7. The method for preparing a tin-lead perovskite solar cell according to claim 6, characterized in that: The preparation of the glass substrate provided with a hole transport layer comprises the following steps: The PEDOT:PSS aqueous solution was coated on the glass substrate by spin coating; A first annealing treatment is performed to obtain a glass substrate provided with a hole transport layer.

8. The method for preparing a tin-lead perovskite solar cell according to claim 6 or 7, characterized in that: After the perovskite layer is prepared, the electron transport layer, the passivation layer and the metal electrode are prepared in sequence.

9. The method for preparing a tin-lead perovskite solar cell according to claim 8, characterized in that: The electron transport layer and the passivation layer are prepared by vacuum evaporation.

10. A tin-lead perovskite solar cell, characterized in that: The tin-lead perovskite solar cell is prepared by the preparation method of any one of claims 1 to 9, wherein the perovskite layer of the tin-lead perovskite solar cell is doped with a dopant, and the dopant includes 2-thiophenecarboxamide, 2-thiopheneethylamine or 2-thiopheneacetamide.

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