Perovskite solar cell and preparation method thereof

Abstract

The application discloses a perovskite solar cell and a preparation method thereof, and the preparation method comprises the following steps: pretreating FTO conductive glass; preparing a titanium diisopropoxy bisacetylacetone / anhydrous n-butanol solution, and spin coating the titanium diisopropoxy bisacetylacetone / anhydrous n-butanol solution on the pretreated FTO conductive glass to obtain a dense layer; preparing a titanium dioxide slurry / anhydrous ethanol solution, and spin coating the titanium dioxide slurry / anhydrous ethanol solution on the dense layer to obtain a mesoporous film layer; preparing a perovskite precursor solution, and spin coating the perovskite precursor solution on the mesoporous film layer to obtain a perovskite film layer; preparing a trimethylated sulfoxide solution, and spin coating the trimethylated sulfoxide solution on the perovskite film layer to obtain a passivation layer; and depositing an electrode on the passivation layer and the FTO conductive glass after a hole transport layer is arranged on the passivation layer. The perovskite solar cell can be obtained, and internal defects of the perovskite film layer are passivated.

Description

Technical Field

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

[0002] Solution-processable hybrid organic-inorganic halide perovskites can be used in solar cells to obtain perovskite solar cells (PSCs).

[0003] Currently, the solar-to-electricity conversion efficiency (PCE) of perovskite solar cells (PSCs) has exceeded 25%, and the price is low. However, perovskites have poor stability against water, light, and heat. It is reported that the expected lifespan of PSCs is at most 10,000 hours, which is not competitive in the market compared with the 25-year lifespan of silicon solar cells. To improve the commercial value of perovskites, it is necessary to further improve their long-term stability.

[0004] Perovskite refers to a class of ceramic oxides with a basic structure of ABX3. Its crystal structure belongs to the cubic crystal system. B and X ions form an octahedral structure [BX6] 4− through strong coordination bonds. B is located at the center of the octahedron, and X is located at the vertices of the octahedron. The octahedrons are extended through corner sharing to form a 3D network structure, and the A-site cations are filled in the voids formed by the 3D network of octahedrons. This perovskite with an ideal lattice structure is also called three-dimensional perovskite (3D perovskite). When the A-site ions are small enough, the integrity of its [BX6]4− cubic configuration can be maintained. Their crystal stability and possible structures are determined by the Goldschmidt tolerance factor (t) and the octahedral factor (μ): t = (rA + rB) / (√2(rB + rX)), where rA, rB, and rX are the ionic radii of the corresponding ions, and μ = rB / rX. To maintain the three-dimensional structure of perovskite, t and μ usually must be within the ranges of 0.81 < t < 1.11 and 0.44 < μ < 0.90, respectively. Otherwise, chain-like one-dimensional perovskite (1D perovskite) or layered two-dimensional perovskite (2D perovskite) will be formed, and the activities of 1D perovskite and 2D perovskite are far less than those of 3D perovskite.

[0005] The basic structure of a perovskite solar cell device includes a conductive glass, an electron transport layer, a perovskite layer, a hole transport layer, and a metal electrode. Due to the properties of the device itself and the production process, defects will be generated in the perovskite. The defects make the perovskite active and easy to decompose, thus forming non-radiative recombination, which in turn affects the device performance and stability.

[0006] Passivating perovskites can reduce defects in perovskites and is an effective strategy for improving the performance of perovskite solar cells. As a form of interface engineering, passivating perovskites can improve the quality of the perovskite film, reduce the probability of nonradiative recombination of electrons and holes, and effectively improve the photoelectric performance and stability of perovskite solar cells. Previous studies have demonstrated that passivating low-dimensional perovskites can effectively improve the stability of solar cells.

[0007] Stable one-dimensional / three-dimensional perovskite solar cells (1D / 3D PSCs) can be prepared by introducing large-diameter organic cations into 3D perovskite precursors or by forming a sufficiently large organic cation thin layer on the surface of 3D perovskite films. 1D / 3D PSCs exhibit both environmental stability and good photovoltaic performance. Currently, materials used to form one-dimensional perovskites in perovskite layer passivation technology include lead methylammonium iodide (MAPbI3), 2-(1H-pyrazol-1-yl)pyridine (PZPY), thiazole ammonium iodide (TAI), pyrrolidine hydroiodide (PyI), propargyl ammonium (PA+), and 2-diethylaminoethyl chloride hydrochloride (DEAECCl). Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the prior art and provide a perovskite solar cell and its preparation method, which can obtain a perovskite solar cell in which the internal defects of the perovskite thin film layer are passivated.

[0009] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0010] On one hand, the present invention provides a method for preparing a perovskite solar cell, comprising the following steps:

[0011] a. Pre-treated FTO conductive glass;

[0012] b. Prepare a diisopropoxydiacetylacetonate titanium / anhydrous n-butanol solution, and spin-coat the diisopropoxydiacetylacetonate titanium / anhydrous n-butanol solution onto the pretreated FTO conductive glass to obtain a dense layer;

[0013] c. Prepare a titanium dioxide slurry / anhydrous ethanol solution and spin-coat the titanium dioxide slurry / anhydrous ethanol solution onto a dense layer to obtain a mesoporous thin film layer;

[0014] d. Prepare a perovskite precursor solution and spin-coat the perovskite precursor solution onto a mesoporous thin film layer to obtain a perovskite thin film layer.

[0015] e. Prepare a trimethyl sulfoxide solution and spin-coat the trimethyl sulfoxide solution onto a perovskite thin film to obtain a passivation layer;

[0016] After setting a hole transport layer on the passivation layer, electrodes are deposited on the hole transport layer and FTO conductive glass to obtain a perovskite solar cell.

[0017] Furthermore, step a includes:

[0018] After ultrasonically cleaning the FTO conductive glass with deionized water, glass cleaner, isopropanol, ethanol, and deionized water in sequence, the FTO conductive glass was dried and then placed in an ultraviolet-ozone device for treatment before use.

[0019] Furthermore, step b includes:

[0020] Diisopropoxydiacetylacetonate titanium was dissolved in anhydrous n-butanol to obtain a diisopropoxydiacetylacetonate titanium / anhydrous n-butanol solution, wherein the volume ratio of diisopropoxydiacetylacetonate titanium to anhydrous n-butanol was (1~2):(10~16).

[0021] Diisopropoxydiacetylacetone titanium / anhydrous n-butanol solution was spin-coated onto pretreated FTO conductive glass at a rotation speed of 1500~2000 rpm, followed by drying to form a dense layer. The spin-coating time was greater than or equal to 10 s.

[0022] Furthermore, step c includes:

[0023] Titanium dioxide slurry was dissolved in anhydrous ethanol to obtain a titanium dioxide slurry / anhydrous ethanol solution, wherein the mass-volume ratio of titanium dioxide slurry to anhydrous ethanol was 1:(6~9) g / ml;

[0024] Titanium dioxide slurry / anhydrous ethanol solution was spin-coated onto a dense layer at a rotation speed of ≥4500 rpm, followed by annealing to form a mesoporous thin film layer, wherein the spin-coating time was ≥10 s.

[0025] Furthermore, step d includes:

[0026] Dimethyl sulfoxide and N,N-dimethylformamide were mixed to obtain a mixture, and formamidine iodide, lead iodide and methylchloromethylamine were dissolved in the mixture to obtain a perovskite precursor solution;

[0027] After spin-coating the perovskite precursor solution onto the mesoporous film layer at a speed of 3000 rpm, diethyl ether was spin-coated onto the mesoporous film layer at a speed of 3000 rpm, and then annealed to form the perovskite film layer. The spin-coating time for the first spin coating was less than or equal to 38 s, and the spin-coating time for the second spin coating was greater than or equal to 20 s.

[0028] Furthermore, in the mixture, the volume ratio of dimethyl sulfoxide to N,N-dimethylformamide is 1:(4~9).

[0029] Furthermore, the molar ratio of formamidine iodocarbamate, lead iodide, and chloromethylamine is 9:9:(3~3.6);

[0030] Furthermore, the volume molar ratio of the mixture to formamidine is 5:9.

[0031] Furthermore, step e includes:

[0032] Trimethyl sulfoxide was dissolved in isopropanol solution to obtain trimethyl sulfoxide solution, wherein the purity of isopropanol solution was 99.7 wt% and the molar concentration of trimethyl sulfoxide solution was 1-10 mmol / L.

[0033] Trimethyl sulfoxide solution was spin-coated onto a perovskite thin film at a rotation speed of 3000 rpm and then annealed to form a passivation layer, wherein the spin-coating time was greater than or equal to 10 s;

[0034] Furthermore, step f includes:

[0035] Spiro-OMeTAD was spin-coated onto the passivation layer at a rotation speed of 3000 rpm to obtain a hole transport layer, wherein the spin-coating time was greater than or equal to 30 s.

[0036] FTO electrode windows are sequentially formed on the hole transport layer, passivation layer, perovskite thin film layer, mesoporous thin film layer and dense layer to expose the FTO conductive glass, and Au is deposited on the exposed FTO conductive glass to obtain the FTO electrode.

[0037] Au is deposited on the hole transport layer to obtain the electrode.

[0038] On the other hand, the present invention provides a perovskite solar cell, which is obtained using the above-described method for preparing a perovskite solar cell.

[0039] Furthermore, the perovskite solar cell includes an electrode, an FTO electrode, and sequentially arranged FTO conductive glass, an electron transport layer, a perovskite thin film layer, a passivation layer, and a hole transport layer.

[0040] The electrode is disposed on the hole transport layer;

[0041] One end of the FTO electrode penetrates through the electron transport layer, the perovskite thin film layer, the passivation layer and the hole transport layer, and abuts against the FTO conductive glass.

[0042] The electron transport layer includes a dense layer and a mesoporous thin film layer.

[0043] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0044] This invention utilizes trimethyl thionyl chloride solution to modify perovskite thin film layers, thereby passivating internal defects in the perovskite thin film layers, promoting charge transport in perovskite solar cells, enhancing carrier lifetime, improving crystallinity and grain size, and suppressing nonradiative recombination in perovskite solar cells, thus improving the photoelectric performance and stability of perovskite solar cells. Attached Figure Description

[0045] Figure 1 These are the transient photoluminescence spectra of the perovskite solar cells prepared in Examples 1, 2, and 3 of this invention;

[0046] Figure 2 These are the steady-state photoluminescence spectra of the perovskite solar cells prepared in Examples 1, 2, and 3 of this invention. Detailed Implementation

[0047] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0048] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0049] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] The method for fabricating the perovskite solar cell of this application includes the following steps:

[0051] a. Pre-treated FTO conductive glass.

[0052] When applying the method, step a includes the following steps:

[0053] After ultrasonic cleaning of FTO conductive glass in sequence with deionized water, glass cleaner, isopropanol, ethanol, and deionized water, the volume ratio of glass cleaner to deionized water was 1:3, and the duration of each ultrasonic cleaning was 20 minutes.

[0054] a2 uses a 120°C oven to dry the FTO conductive glass, and then places the dried FTO conductive glass in an ultraviolet-ozone device for 20 minutes to improve the wettability of the FTO conductive glass.

[0055] b. Prepare a diisopropoxydiacetylacetonate titanium / anhydrous n-butanol solution, and spin-coat the diisopropoxydiacetylacetonate titanium / anhydrous n-butanol solution onto the pretreated FTO conductive glass to obtain a dense layer with a thickness of 50 nm.

[0056] When applying the method, step b includes the following steps:

[0057] b1. Diisopropoxydiacetylacetonate titanium is dissolved in anhydrous n-butanol to obtain a diisopropoxydiacetylacetonate titanium / anhydrous n-butanol solution, wherein the volume ratio of diisopropoxydiacetylacetonate titanium to anhydrous n-butanol is (1~2):(10~16), for example, 0.2 ml of diisopropoxydiacetylacetonate titanium and 3.2 ml of anhydrous n-butanol.

[0058] b2 spin-coating a diisopropoxydiacetylacetone titanium / anhydrous n-butanol solution onto pretreated FTO conductive glass at a rotation speed of 1500~2000 rpm, followed by drying to form a dense layer, wherein the spin-coating time is greater than or equal to 10 s.

[0059] c. Prepare a titanium dioxide slurry / anhydrous ethanol solution and spin-coat the titanium dioxide slurry / anhydrous ethanol solution onto a dense layer to obtain a 70 nm thick mesoporous film layer.

[0060] When applying the method, step c includes the following steps:

[0061] c1 Dissolve titanium dioxide slurry in anhydrous ethanol to obtain a titanium dioxide slurry / anhydrous ethanol solution, wherein the mass-to-volume ratio of titanium dioxide slurry to anhydrous ethanol is 1:(6~9) g / ml, for example, 0.3 g of titanium dioxide slurry and 2.4 ml of anhydrous ethanol.

[0062] c2 spin-coats titanium dioxide slurry / anhydrous ethanol solution onto a dense layer at a rotation speed of ≥4500 rpm, followed by annealing to form a mesoporous thin film layer, wherein the spin-coating time is ≥10 s.

[0063] In addition, the annealing conditions are annealing at 500 °C for 1 h.

[0064] Those skilled in the art can assemble a dense layer and a mesoporous thin film layer into an electron transport layer with a thickness of approximately 120 nm.

[0065] d. Prepare a perovskite precursor solution and spin-coat the perovskite precursor solution onto a mesoporous thin film layer to obtain a perovskite thin film layer.

[0066] When applying the method, step d includes the following steps:

[0067] d1. Dimethyl sulfoxide and N,N-dimethylformamide were mixed to obtain a mixture, and formamidine iodide, lead iodide and methylchloromethylamine were dissolved in the mixture to obtain a perovskite precursor solution;

[0068] In the mixture, the volume ratio of dimethyl sulfoxide to N,N-dimethylformamide is 1:(4~9); the molar ratio of formamidine, lead iodide, and chloromethylamine is 9:9:(3~3.6); and the volume molar ratio of the mixture to formamidine is 5:9. For example, 0.9 mmol of formamidine, 0.9 mmol of lead iodide, and 0.315 mmol of chloromethylamine are dissolved in 0.1 ml of dimethyl sulfoxide and 0.4 ml of dimethylformamide, and stirred at room temperature for 12 h to obtain a perovskite precursor solution.

[0069] d2 After spin-coating the perovskite precursor solution onto the mesoporous film layer at a speed of 3000 rpm, 1 ml of diethyl ether was spin-coated onto the mesoporous film layer as an antisolvent at a speed of 3000 rpm, and then annealed to form a 400 nm perovskite film layer.

[0070] The first spin coating time was less than or equal to 38 s, and the second spin coating time was greater than or equal to 20 s. Furthermore, the annealing treatment was performed at 150 ℃ for 10 min in a single pass.

[0071] e. Prepare a trimethyl sulfoxide solution and spin-coat the trimethyl sulfoxide solution onto a perovskite thin film to obtain a passivation layer.

[0072] When applying, step e includes the following steps:

[0073] e1 Dissolves trimethyl sulfoxide in isopropanol solution to obtain trimethyl sulfoxide solution, wherein the purity of isopropanol solution is 99.7 wt% and the molar concentration of trimethyl sulfoxide solution is 1-10 mmol / L.

[0074] e2 spin-coated a trimethyl sulfoxide solution onto a perovskite thin film at a rotation speed of 3000 rpm, and then annealed to form a 10-20 nm passivation layer.

[0075] The spin coating time is greater than or equal to 10 seconds. Furthermore, the annealing treatment is performed at 130°C for a single annealing cycle of 10 minutes.

[0076] After setting a hole transport layer on the passivation layer, electrodes are deposited on the hole transport layer and FTO conductive glass to obtain a perovskite solar cell.

[0077] When applying the method, step f includes the following steps:

[0078] f1 spin-coated Spiro-OMeTAD onto the passivation layer at a rotation speed of 3000 rpm to obtain a hole transport layer with a thickness of 70 nm, wherein the spin-coating time is greater than or equal to 30 s.

[0079] The Spiro-OMeTAD used in this application was purchased from Xi'an Baolai Optoelectronics Technology Co., Ltd., with item number PLT502012T.

[0080] f2 utilizes GBL to sequentially create FTO electrode windows on the hole transport layer, passivation layer, perovskite thin film layer, mesoporous thin film layer, and dense layer, exposing the FTO conductive glass. Au is then deposited on the exposed FTO conductive glass using a vacuum evaporation device to obtain the FTO electrode.

[0081] The GBL used in this application was purchased from Nanjing Wanqing Chemical Glass Instrument Co., Ltd., with item number H811086.

[0082] f3 utilizes a vacuum evaporation apparatus to deposit Au on a hole transport layer, obtaining an electrode with a thickness of 80 nm.

[0083] In practical applications, those skilled in the art can prepare perovskite solar cells according to the above-described method for preparing perovskite solar cells.

[0084] The obtained perovskite solar cell includes an electrode, an FTO electrode, and sequentially arranged FTO conductive glass, an electron transport layer, a perovskite thin film layer, a passivation layer, and a hole transport layer, as shown in the reference. Figure 1 .

[0085] The electrode in this application is disposed on the hole transport layer; one end of the FTO electrode penetrates through the electron transport layer, the perovskite thin film layer, the passivation layer and the hole transport layer, and abuts against the FTO conductive glass.

[0086] The electron transport layer comprises a dense layer and a mesoporous thin film layer. The perovskite thin film layer is disposed on the mesoporous thin film layer, which is disposed on the dense layer, and the dense layer is disposed on the FTO conductive glass.

[0087] To compare the effect of the molar concentration of trimethyl sulfoxide solution on the parameters of the finished perovskite solar cells, this application provides three sets of examples.

[0088] Example 1

[0089] A perovskite solar cell was obtained by following the steps of the fabrication method.

[0090] Step 1 involves ultrasonically cleaning the FTO conductive glass sequentially with deionized water, glass cleaner, isopropanol, ethanol, and then deionized water. The volume ratio of glass cleaner to deionized water is 1:3, and each ultrasonic cleaning session lasts for 20 minutes.

[0091] Step 2: Dry the FTO conductive glass in an oven at 120°C, and then place the dried FTO conductive glass in an ultraviolet-ozone device for 20 minutes to improve the wettability of the FTO conductive glass.

[0092] Step 3: Dissolve diisopropoxydiacetylacetonate in anhydrous n-butanol to obtain a diisopropoxydiacetylacetonate / anhydrous n-butanol solution, wherein the amount of diisopropoxydiacetylacetonate is 0.2 ml and the amount of anhydrous n-butanol is 3.2 ml.

[0093] Step 4: Spin-coat the diisopropoxydiacetylacetone titanium / anhydrous n-butanol solution onto the pretreated FTO conductive glass at a rotation speed of 2000 rpm, and then dry it to form a dense layer with a thickness of 50 nm. The spin-coating time is greater than or equal to 10 s.

[0094] Step 5: Dissolve the titanium dioxide slurry in anhydrous ethanol to obtain a titanium dioxide slurry / anhydrous ethanol solution, wherein the titanium dioxide slurry is 0.3 g and the anhydrous ethanol is 2.4 ml.

[0095] Step 6: Spin-coat the titanium dioxide slurry / anhydrous ethanol solution onto the dense layer at a rotation speed of 4500 rpm, and then anneal the layer to form a mesoporous thin film layer. The spin-coating time is greater than or equal to 10 s.

[0096] In addition, the annealing process involves sintering at 500°C for 1 hour.

[0097] Step 7: Dissolve 0.9 mmol formamidinium iodide, 0.9 mmol lead iodide and 0.315 mmol chloromethylamine in 0.1 ml dimethyl sulfoxide and 0.4 ml dimethylformamide, and stir at room temperature for 12 h to obtain a perovskite precursor solution.

[0098] Step 8: After spin-coating the perovskite precursor solution onto the mesoporous film layer at a speed of 3000 rpm, spin-coat 1 ml of diethyl ether as an antisolvent onto the mesoporous film layer at a speed of 3000 rpm, and then anneal the film to form a 400 nm perovskite film layer.

[0099] The spin coating time for the first spin coating was less than or equal to 38 s, and the spin coating time for the second spin coating was greater than or equal to 20 s. In addition, the annealing treatment was a one-step annealing at 150 ℃ for 10 min.

[0100] Step 9: Dissolve 0.01 mmol of trimethyl sulfoxide in 10 ml of isopropanol with a purity of 99.7% to obtain a 1 mmol / L trimethyl sulfoxide solution.

[0101] Step 10: Spin-coat the trimethyl sulfoxide solution onto the perovskite thin film at a rotation speed of 3000 rpm, and anneal the film to form a 10-20 nm passivation layer.

[0102] The spin coating time is greater than or equal to 10 seconds. Furthermore, the annealing process is a one-step annealing at 130°C for 10 minutes.

[0103] Step 11: Spiro-OMeTAD is spin-coated onto the passivation layer at a rotation speed of 3000 rpm to obtain a hole transport layer with a thickness of 70 nm, wherein the spin-coating time is greater than or equal to 30 s.

[0104] Step 12: Using GBL, FTO electrode windows are sequentially opened on the hole transport layer, passivation layer, perovskite thin film layer, mesoporous thin film layer and dense layer, so that the FTO conductive glass is exposed. Au is deposited on the exposed FTO conductive glass using a vacuum evaporation device to obtain the FTO electrode.

[0105] Step 13: Au is deposited on the hole transport layer using a vacuum evaporation apparatus to obtain an electrode with a thickness of 80 nm.

[0106] Step 14 finally yields the perovskite solar cell.

[0107] This invention utilizes trimethyl thionyl chloride solution to modify perovskite thin film layers, thereby passivating internal defects in the perovskite thin film layers, promoting charge transport in perovskite solar cells, enhancing carrier lifetime, improving crystallinity and grain size, and suppressing nonradiative recombination in perovskite solar cells, thus improving the photoelectric performance and stability of perovskite solar cells.

[0108] Example 2

[0109] The difference between this embodiment and Embodiment 1 lies in step 9:

[0110] In this embodiment, 0.05 mmol of trimethyl sulfoxide was dissolved in 10 ml of isopropanol with a purity of 99.7% to obtain a 5 mmol / L trimethyl sulfoxide solution.

[0111] Example 3

[0112] The difference between this embodiment and Embodiment 1 lies in step 9:

[0113] In this embodiment, 0.1 mmol of trimethyl sulfoxide was dissolved in 10 ml of isopropanol with a purity of 99.7% to obtain a 10 mmol / L trimethyl sulfoxide solution.

[0114] The characteristic parameters of the perovskite solar cells obtained in Examples 1-3 were tested respectively, as detailed in Table 1.

[0115]

[0116] As shown in Table 1, the perovskite solar cell in the blank control group has a photoelectric conversion efficiency of 17.60%, an open-circuit voltage of 0.982V, and a short-circuit current of 24.62mA / cm². 2 The fill factor was 70.39%. When the passivation layer was obtained using a 10 mmol / L trimethyl sulfoxide solution, the perovskite solar cell achieved a photoelectric conversion efficiency as high as 21.71%, an open-circuit voltage of 1.071 V, and a short-circuit current of 26.09 mA / cm². 2 The fill factor is 78.65%. It is evident that by adding a highly stable one-dimensional passivation layer of trimethyl thionyl chloride on the perovskite thin film, the photovoltaic performance of the perovskite solar cell is improved; for example, the photoelectric conversion efficiency, open-circuit voltage, short-circuit current, and fill factor are all enhanced.

[0117] Furthermore, this application analyzes the effects of modifying the perovskite thin film layer with trimethyl thionyl chloride solution on the carrier dynamics and recombination of perovskite solar cells.

[0118] refer to Figure 1 It can be seen that, compared with the blank control group, the PL intensity of the perovskite solar cell increases with the increase of trimethyl thionyl chloride solution. This shows that after modifying the perovskite thin film layer with trimethyl thionyl chloride solution, the number of trapping centers is reduced and nonradiative recombination caused by defects can be effectively suppressed.

[0119] refer to Figure 2 Compared to the blank control group, the normalized PL intensity of the perovskite solar cell increased with the increase of trimethyl thionyl chloride solution. It can be seen that the perovskite thin film layer modified with trimethyl thionyl chloride solution has a longer average carrier lifetime.

[0120] In summary, modifying the perovskite thin film layer with trimethyl thionyl chloride solution can effectively passivate the internal defects of the perovskite thin film layer, thereby suppressing non-radiative recombination in perovskite solar cells and improving the photoelectric performance and stability of perovskite solar cells.

[0121] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a perovskite solar cell, characterized in that, Includes the following steps: a. Pre-treated FTO conductive glass; b. Prepare a diisopropoxydiacetylacetonate titanium / anhydrous n-butanol solution, and spin-coat the diisopropoxydiacetylacetonate titanium / anhydrous n-butanol solution onto the pretreated FTO conductive glass to obtain a dense layer; c. Prepare a titanium dioxide slurry / anhydrous ethanol solution and spin-coat the titanium dioxide slurry / anhydrous ethanol solution onto a dense layer to obtain a mesoporous thin film layer; d. Prepare a perovskite precursor solution and spin-coat the perovskite precursor solution onto a mesoporous thin film layer to obtain a perovskite thin film layer. e. Prepare a trimethyl sulfoxide solution and spin-coat the trimethyl sulfoxide solution onto a perovskite thin film to obtain a passivation layer; f After setting a hole transport layer on the passivation layer, electrodes are deposited on the hole transport layer and FTO conductive glass to obtain a perovskite solar cell. Step d includes: Dimethyl sulfoxide and N,N-dimethylformamide were mixed to obtain a mixture, and formamidine iodide, lead iodide and methylchloromethylamine were dissolved in the mixture to obtain a perovskite precursor solution; After spin-coating the perovskite precursor solution onto the mesoporous film layer at a speed of 3000 rpm, diethyl ether was spin-coated onto the mesoporous film layer as an antisolvent at a speed of 3000 rpm, and then annealed to form the perovskite film layer. In the mixture, the volume ratio of dimethyl sulfoxide to N,N-dimethylformamide is 1:(4~9). And / or, the molar ratio of formamidine iodocarbamate, lead iodide and chloromethylamine is 9:9:(3~3.6); And / or, the volume molar ratio of the mixture to formamidine is 5:9; Trimethyl sulfoxide was dissolved in isopropanol solution to obtain trimethyl sulfoxide solution, wherein the purity of isopropanol solution was 99.7 wt% and the molar concentration of trimethyl sulfoxide solution was 10 mmol / L. Trimethyl sulfoxide solution was spin-coated onto a perovskite thin film at a rotation speed of 3000 rpm, and then annealed to form a passivation layer.

2. The method for preparing a perovskite solar cell according to claim 1, characterized in that, Step a includes: After ultrasonically cleaning the FTO conductive glass with deionized water, glass cleaner, isopropanol, ethanol, and deionized water in sequence, the FTO conductive glass was dried and then placed in an ultraviolet-ozone device for treatment before use.

3. The method for preparing a perovskite solar cell according to claim 1, characterized in that, Step b includes: Diisopropoxydiacetylacetonate titanium was dissolved in anhydrous n-butanol to obtain a diisopropoxydiacetylacetonate titanium / anhydrous n-butanol solution, wherein the volume ratio of diisopropoxydiacetylacetonate titanium to anhydrous n-butanol was (1~2):(10~16). Diisopropoxydiacetylacetone titanium / anhydrous n-butanol solution was spin-coated onto pretreated FTO conductive glass at a rotation speed of 1500~2000 rpm, and then dried to form a dense layer.

4. The method for preparing a perovskite solar cell according to claim 1, characterized in that, Step c includes: Titanium dioxide slurry was dissolved in anhydrous ethanol to obtain a titanium dioxide slurry / anhydrous ethanol solution, wherein the mass-volume ratio of titanium dioxide slurry to anhydrous ethanol was 1:(6~9) g / ml; Titanium dioxide slurry / anhydrous ethanol solution was spin-coated onto a dense layer at a rotation speed of 4500 rpm or higher, followed by annealing to form a mesoporous thin film layer.

5. The method for preparing a perovskite solar cell according to claim 1, characterized in that, Step f includes: Spiro-OMeTAD was spin-coated onto the passivation layer at a rotation speed of 3000 rpm to obtain the hole transport layer; FTO electrode windows are sequentially formed on the hole transport layer, passivation layer, perovskite thin film layer, mesoporous thin film layer and dense layer to expose the FTO conductive glass, and Au is deposited on the exposed FTO conductive glass to obtain the FTO electrode. Au is deposited on the hole transport layer to obtain the electrode.

6. A perovskite solar cell, characterized in that, The perovskite solar cell is obtained using the fabrication method according to any one of claims 1-5.

7. The perovskite solar cell according to claim 6, characterized in that, It includes an electrode, an FTO electrode, and sequentially arranged FTO conductive glass, an electron transport layer, a perovskite thin film layer, a passivation layer, and a hole transport layer. The electrode is disposed on the hole transport layer; One end of the FTO electrode penetrates through the electron transport layer, the perovskite thin film layer, the passivation layer and the hole transport layer, and abuts against the FTO conductive glass. The electron transport layer includes a dense layer and a mesoporous thin film layer.

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