Multifunctional complex modified perovskite solar cell and preparation method thereof

Abstract

The invention discloses a multifunctional complex modified perovskite solar cell and a preparation method thereof. A multifunctional complex ammonia borane (BNH6) is introduced into perovskite solar cells (PSCs), so that iodine reduction and double-layer optimization are realized at the same time. The PSCs not only can interact with SnO2 and a perovskite layer, but also can prevent I <-> from being oxidized and reduce I0 into I <->, so that the efficiency and the stability of the PSCs are improved. The prepared perovskite solar cell achieves 25.66% of power conversion efficiency (PCE), has excellent stability, and still keeps 90% of initial PCE after continuous tracking of the maximum power point for 500 hours.

Description

Technical Field

[0001] This invention belongs to the field of solar cell technology, specifically relating to a perovskite solar cell modified with a multifunctional complex and its preparation method. Background Technology

[0002] Organic-inorganic hybrid perovskite solar cells (PSCs) have attracted widespread attention due to their excellent photoelectric performance. Over the past few decades, the power conversion efficiency (PCE) of PSCs has rapidly reached 26.1%. However, when devices are exposed to environmental factors such as moisture, oxygen, light, and thermal stress, these factors accelerate device aging and lead to various defects.

[0003] Studies have shown that in the air environment, I - It is easily oxidized to I 0 These act as non-radiative recombination centers, thus accelerating the degradation of the perovskite layer. For example, I - Oxidized to I 0 It will then volatilize under light and high temperature, producing halide defects and accompanied by I 0 Migration. The color of formamidin hydroiodate (FAI) powder and solution may also change after prolonged storage due to I... - It gradually turns yellow due to oxidation. Furthermore, when the perovskite film is exposed to air, the I0 at the interface... - They are more susceptible to oxidation and the formation of defects. Therefore, there is an urgent need to propose a strategy to prevent halide oxidation and optimize the interface.

[0004] Furthermore, current interface engineering strategies typically employ two or more additives to modify the dual interfaces (electron transport layer / perovskite and perovskite / hole transport layer) of the perovskite layer. This makes the device fabrication process overly complex, hindering rapid device fabrication and commercial applications. In view of the above background and problems, this invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a perovskite solar cell modified with a multifunctional complex and its preparation method. This multifunctional complex can not only achieve iodine reduction but also perform dual-interface optimization.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A multifunctional complex-modified perovskite solar cell has the following structure from bottom to top: a substrate layer, a cathode layer, a complex-modified electron transport layer, a complex-modified perovskite layer, a hole transport layer, and a metal anode layer; wherein the complex is ammonia borane (BNH6).

[0007] In a preferred embodiment of the present invention, the substrate layer is transparent glass, the cathode layer is ITO, the complex-modified electron transport layer is an ammonia borane-modified tin dioxide (SnO2) layer, the complex-modified perovskite layer is an ammonia borane-modified perovskite layer, the hole transport layer is a 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) layer, and the metal anode layer is gold (Au).

[0008] Furthermore, the perovskite is Cs 0.05 FA 0.95 PbI3 perovskite.

[0009] In a preferred embodiment of the present invention, the thickness of the complex-modified electron transport layer is 20-30 nm, the thickness of the complex-modified perovskite layer is 600-700 nm, the thickness of the hole transport layer (Spiro-OMeTAD layer) is 90-120 nm, and the thickness of the metal anode layer (Au layer) is 80-100 nm.

[0010] The present invention also provides a method for preparing the perovskite solar cell modified with the above-mentioned multifunctional complex.

[0011] The method for preparing a multifunctional complex-modified perovskite solar cell provided by this invention includes the following steps: (1) A complex-modified electron transport layer is prepared on a substrate with a cathode layer; (2) Prepare a complex-modified perovskite layer on a complex-modified electron transport layer; (3) A hole transport layer is prepared on the complex-modified perovskite layer; (4) A metal electrode is prepared on the hole transport layer to obtain the perovskite solar cell modified by the multifunctional complex.

[0012] In step (1) of the above method, the substrate with the cathode layer is an ITO glass substrate, which needs to be treated as follows before use: the ITO glass is ultrasonically cleaned with water, acetone and isopropanol for 15 min in sequence, dried with a nitrogen gun after cleaning, and then placed in a plasma cleaner for ultraviolet ozone treatment for 10 min.

[0013] In step (1) of the above method, an ammonia borane-modified tin dioxide (SnO2) layer is prepared on a substrate with a cathode layer (such as an ITO glass substrate). The specific preparation method is as follows: BNH6 aqueous solution is mixed with SnO2 colloidal aqueous solution to obtain SnO2 colloidal aqueous solution containing BNH6, and the SnO2 colloidal aqueous solution containing BNH6 is spin-coated on a substrate with a cathode layer (such as a treated ITO glass substrate), and annealed to form a complex-modified electron transport layer.

[0014] The annealing temperature is 100~180℃, and the annealing time is 0.5~1.5h, specifically, annealing at 150℃ for 30min.

[0015] According to one embodiment of the present invention, a 1 mg / mL aqueous solution of BNH6 and an aqueous colloidal solution of SnO2 (15 wt.%) are mixed at a volume ratio of 2:1 to obtain an aqueous colloidal solution of SnO2 containing BNH6; the spin coating speed is 4000 rpm and the spin coating time is 30 s. The annealing conditions are: annealing at 150 ℃ for 30 min.

[0016] In step (2) of the above method, the method for preparing a complex-modified perovskite layer on a complex-modified electron transport layer includes the following steps: Cs 0.05 FA 0.95 A PbI3 perovskite precursor solution was spin-coated onto a complex-modified electron transport layer. Before the spin-coating was completed, diethyl ether, the antisolvent, was dropped onto the substrate, followed by annealing to form a perovskite film. Then, an isopropanol solution of BNH6 was spin-coated onto the perovskite film to form a complex-modified perovskite layer.

[0017] Wherein, the Cs 0.05 FA 0.95 The preparation method of PbI3 perovskite precursor solution is as follows: Formamidinium hydroiodate (FAI), CsI, PbI2 and methylammonium chloride (MACl) are dissolved in a solvent in a mass ratio of 13:1:40:1.8, and stirred overnight at room temperature to form CsI3 perovskite precursor solution. 0.05 FA 0.95 PbI3 perovskite precursor solution.

[0018] The solvent can be a mixed solvent obtained by mixing DMF and DMSO in a volume ratio of 4:1 to 10:1.

[0019] The antisolvent diethyl ether is added 10-20 seconds before the end of spin coating, preferably 20 seconds.

[0020] According to one embodiment of the present invention, a perovskite precursor solution (80 μL) was spin-coated at 1000 rpm for 10 s and then at 5000 rpm for 30 s onto the SnO2 electron transport layer of an ITO glass substrate. 20 s before the end of spin-coating, 800 μL of diethyl ether was rapidly dropped onto the substrate as an antisolvent.

[0021] The annealing temperature is 100~150℃ and the annealing time is 0.5~1.5h, specifically, annealing at 120℃ for 1h.

[0022] The concentration of the isopropanol solution of BNH6 is 0.1-2 mg / mL.

[0023] The spin-coating conditions for the isopropanol solution of BNH6 are as follows: spin-coating at a speed of 4000 rpm for a spin-coating time of 30 s.

[0024] After step (2) and before step (3), there is also a step of passivating the complex-modified perovskite layer prepared in step (2), specifically as follows: spin-coating 4-MeOPEAI solution onto the complex-modified perovskite layer, and then annealing at 100°C for 5 min to passivate the complex-modified perovskite layer.

[0025] According to an embodiment of the present invention, 4-MeOPEAI was dissolved in isopropanol (3 mg / mL); 100 μL of 4-MeOPEAI solution was spin-coated onto the complex-modified perovskite layer at 4000 rpm for 30 s, and then the complex-modified perovskite layer was passivated by annealing at 100 °C for 5 min.

[0026] In step (3) of the above method, the hole transport layer is a 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) layer. The specific preparation method is as follows: a Spiro-OMeTAD mixed solution is spin-coated onto a complex-modified perovskite layer to form a Spiro-OMeTAD hole transport layer.

[0027] According to one embodiment of the present invention, the preparation method of the Spiro-OMeTAD mixed solution is as follows: Spiro-OMeTAD (72.3 mg) is dissolved in 1000 μL of chlorobenzene, and Li-TFSI solution (260 mg / mL) (17.5 μL) and TBP (28.8 μL) are added. The Spiro-OMeTAD mixed solution (50 μL) is spin-coated onto the complex-modified perovskite layer at 4000 rpm for 30 s, and the prepared sample is oxidized in a desiccator for 10 h.

[0028] In step (4) of the above method, a metal electrode is prepared on the hole transport layer by vacuum evaporation.

[0029] In the complex-modified perovskite solar cells described above, BNH6 can not only simultaneously passivate defects on the perovskite surface and at the buried interface, but also effectively convert I... 0 Restore to I - This improves the efficiency and stability of the device, with a PCE of 25.66%, and retains 90% of the initial PCE after 500 hours of continuous tracking at maximum power point.

[0030] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention achieves iodine reduction and bilayer optimization by adding multifunctional complex BNH6 to the electron transport layer and the surface of the perovskite layer, which significantly improves the power conversion efficiency and stability of the battery.

[0031] (2) The PCE of the perovskite solar cell modified with multifunctional complex prepared by the present invention can reach 25.66%, and it still retains 90% of the initial PCE after continuous tracking of the maximum power point for 500 hours.

[0032] (3) This invention provides a simple and effective preparation strategy for perovskite solar cells. The preparation process is simple, the cost is low, the power conversion efficiency and stability are significantly improved, reaching the world's first-class level, and it has broad application prospects. Attached Figure Description

[0033] Figure 1 This is a ball-and-stick model of ammonia borane (BNH6) as described in this invention.

[0034] Figure 2 The JV curves are shown for the standard perovskite solar cell prepared in Comparative Example 1 and the complex-modified perovskite solar cell prepared in Example 1 of this invention.

[0035] Figure 3 This is a comparison of the maximum power point tracking curves of the standard perovskite solar cell prepared in Comparative Example 1 and the complex-modified perovskite solar cell prepared in Example 1.

[0036] Figure 4 This is a comparison of the X-ray photoelectron spectra of the standard perovskite film prepared in Comparative Example 1 and the complex-modified perovskite film prepared in Example 1.

[0037] Figure 5 The NMR spectrum of BNH6 alone after blending with BNH6 and PbI2 is shown.

[0038] Figure 6 The images show scanning electron microscope (SEM) surface images of the standard perovskite film prepared in Comparative Example 1 and the complex-modified perovskite film prepared in Example 1 of this invention.

[0039] Figure 7 The UV-Vis spectra of the standard perovskite film prepared in Comparative Example 1 and the complex-modified perovskite film prepared in Example 1 under accelerated aging conditions at different times, and the comparison diagram of immersion in toluene.

[0040] Figure 8A comparison graph showing the FAI solutions with and without BNH6 added under accelerated aging conditions.

[0041] Figure 9 A comparison of the UV-Vis absorption spectra of FAI solutions with and without BNH6 added under accelerated aging conditions.

[0042] Figure 10 A comparison graph showing FAI solutions with different doses of BNH6 added.

[0043] Figure 11 Comparison of UV-Vis absorption spectra of FAI solutions with different doses of BNH6.

[0044] Figure 12 The JV curves are shown for the complex-modified perovskite solar cells prepared in Examples 2 and 3 of this invention. Detailed Implementation

[0045] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0046] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0047] Comparative Example 1 (1) The ITO glass substrate was ultrasonically cleaned with water, acetone and isopropanol for 15 min in sequence and dried with nitrogen gun. Then it was placed in a plasma cleaner for ultraviolet ozone treatment for 10 min.

[0048] (2) SnO2 colloidal aqueous solution (15 wt.%) was mixed with ultrapure water at a volume ratio of 1:2, and the colloidal aqueous solution was spin-coated on the treated ITO glass substrate at a speed of 4000 rpm for 30 s. Then, it was annealed on a hot stage at 150 ℃ for 30 min to form a SnO2 electron transport layer with a thickness of 20 nm.

[0049] (3) FAI (240.76 mg), CsI (18.19 mg), PbI2 (728.40 mg), and MACl (33.08 mg) powders were dissolved in DMF (888 μL) and DMSO (111 μL) and stirred at room temperature for 6 h to form a perovskite precursor solution. The perovskite precursor solution (80 μL) was spin-coated onto the SnO2 electron transport layer at 1000 rpm for 10 s and then at 5000 rpm for 30 s. 20 s before the end of spin-coating, 800 μL of diethyl ether was rapidly dropped onto the substrate as an antisolvent. The substrate was then annealed at 120 °C and 25% RH for 1 h on a hot plate to form a standard perovskite film with a thickness of 650 nm.

[0050] (4) Dissolve 4-MeOPEAI in isopropanol (3 mg / mL). Spin-coat 100 μL of the 4-MeOPEAI solution at 4000 rpm for 30 s, and then passivate the perovskite film by annealing at 100 °C for 5 min on a hot plate.

[0051] (5) Spiro-OMeTAD (72.3 mg) was dissolved in 1000 μL of chlorobenzene, and Li-TFSI solution (260 mg / mL) (17.5 μL) and TBP (28.8 μL) were added. The solution (50 μL) was spin-coated at 4000 rpm for 30 s, and then the prepared sample was oxidized in a desiccator for 10 h. The thickness of the Spiro-OMeTAD layer was 100 nm.

[0052] (6) Finally, in a vacuum coating machine, through thermal evaporation (<2.5×10 -4 80 nm Au electrode was deposited at Pa.

[0053] Example 1 The difference between this embodiment and Comparative Example 1 is that: Adjustment step (2): Dissolve 0.5 mg BNH6 in 500 μL of ultrapure water to prepare a 1 mg / mL BNH6 aqueous solution, and mix it with SnO2 colloidal aqueous solution (15 wt.%) at a volume ratio of 2:1. Spin-coat the colloidal aqueous solution onto the treated ITO glass substrate at a speed of 4000 rpm for 30 s, and then anneal at 150 ℃ for 30 min on a hot stage to form a complex-modified electron transport layer with a thickness of 20 nm.

[0054] Adjustment step (3): FAI (240.76 mg), CsI (18.19 mg), PbI2 (728.40 mg), and MACl (33.08 mg) powders were dissolved in DMF (888 μL) and DMSO (111 μL) and stirred at room temperature for 6 h to form a perovskite precursor solution. This perovskite precursor solution (80 μL) was spin-coated onto the electron transport layer at 1000 rpm for 10 s and then at 5000 rpm for 30 s. 20 s before the end of spin-coating, 800 μL of diethyl ether was rapidly dropped onto the substrate as an antisolvent. The substrate was then annealed for 1 h at 120 °C and 25% RH on a hot plate. 0.5 mg BNH6 was dissolved in 500 μL of isopropanol (IPA) (1 mg / mL). 100 μL of this solution was then spin-coated onto a substrate at 4000 rpm for 30 s to form a complex-modified perovskite layer with a thickness of 660 nm.

[0055] The remaining steps are the same as those in Comparative Example 1.

[0056] The performance of the complex-modified perovskite solar cell prepared in this embodiment was compared with that of the standard perovskite solar cell prepared in Comparative Example 1. The results are shown in Table 1. Figure 2 As shown, the PCE of the device modified with the obtained complex is significantly improved.

[0057] Table 1 Performance Comparison of Standard and Modified Devices

[0058] See Figure 3 The figure shows a comparison of the maximum power point tracking curves of the standard perovskite solar cell prepared in Comparative Example 1 and the complex-modified perovskite solar cell prepared in Example 1. It can be seen that, under continuous monitoring of AM 1.5 light intensity in an N2 environment, the complex-modified perovskite solar cell can still maintain 90% of its initial efficiency after 500 h, while the standard perovskite solar cell can only maintain 51%.

[0059] See Figure 4 The image shows a comparison of the X-ray photoelectron spectroscopy (XPS) spectra of the standard perovskite film prepared in Comparative Example 1 and the perovskite film modified with the multifunctional complex prepared in Example 1. It can be seen that after adding BNH6 to the electron transport layer, the lattice oxygen (O2)... L The relative intensity of oxygen vacancies decreased (from 62% to 22%), and the relative intensity of oxygen vacancies (O) decreased. V The relative strength of BO2 increased (from 38% to 78%) due to the hydrolysis of BNH6 with water to produce BO2. - Thus occupying O VThis suppresses nonradiative recombination and enhances electron mobility. See Figure 5 The image shows the 1H NMR spectrum of BNH6 alone, blended with BNH6 and PbI2. It can be seen that the peak at 4.41 ppm shows almost no shift, indicating that BN bonds still exist in BNH6. A new peak appears at 5.24 ppm, representing a Pb-N coordination bond. This is due to the breaking of some BN bonds in the BNH6 molecules, allowing the lone pair of N electrons to bind with Pb. 2+ Coordination, passivation defects.

[0060] See Figure 6 The images show scanning electron microscope (SEM) surface images of the standard perovskite film prepared in Comparative Example 1 and the complex-modified perovskite film prepared in Example 1. It can be seen that the grain size of the complex-modified perovskite film is significantly larger than that of the standard perovskite film, and there is no residual PbI2.

[0061] See Figure 7 The images show the UV-Vis spectra of the standard perovskite film prepared in Comparative Example 1 and the complex-modified perovskite film prepared in Example 1 at different times under accelerated aging conditions, as well as a comparison image of the film immersed in toluene. It can be seen that after 72 hours, the Ig in the complex-modified perovskite film... 0 The content was significantly lower than that of the standard perovskite film, and the standard perovskite film had turned yellow and degraded, and the toluene solution had turned into powder. However, the color of the complex-modified perovskite film hardly changed, and the toluene solution soaked in it remained transparent, indicating that the stability of the complex-modified perovskite film was significantly enhanced.

[0062] 171.97 mg of FAI was dissolved in 1 mL of DMF to form a FAI solution (1 mol / mL); the above FAI solution was placed in an air environment and heated continuously at 60 °C for 24 h to form an accelerated aging FAI solution.

[0063] See Figure 8 The figure shows a comparison of FAI solutions with and without BNH6 (0.31 mg) under accelerated aging conditions. It can be seen that after continuous stirring at 60 °C in air, the transparent FAI solution without BNH6 turned pale yellow after 12 h of aging and bright yellow after 24 h, while the FAI solution with added BNH6 remained transparent after 24 h of aging, indicating that BNH6 can inhibit I... - Oxidized to I 0 .

[0064] See Figure 9The image shows a comparison of the UV-Vis absorption spectra of FAI solutions with and without the addition of BNH6 (0.31 mg) under accelerated aging conditions. It can be seen that the absorption peak at 365 nm in the UV-Vis absorption spectrum of the FAI solution without BNH6 gradually increases with aging time. This is due to I... - Oxidized to I 0 The FAI solution with added BNH6 showed almost no peak at 365 nm in its UV-Vis absorption spectrum, indicating that BNH6 can inhibit I... - Oxidized to I 0 .

[0065] See Figure 10 The image shows a comparison of FAI solutions with different dosages of BNH6. It can be seen that as the concentration of BNH6 was gradually increased in the accelerated-aging FAI solution, the yellow color gradually returned to transparency, indicating that BNH6 can enhance the formation of I₂. 0 Restore to I - .

[0066] See Figure 11 The image shows a comparison of the UV-Vis absorption spectra of FAI solutions with different dosages of BNH6. It can be seen that as the BNH6 content gradually increases, the absorption peak at 365 nm decreases significantly, indicating that BNH6 can enhance the formation of I₂. 0 Restore to I - This is because the H bonded to B has a -1 oxidation state and can be oxidized to H2, giving BNH6 its reducing properties.

[0067] Example 2 The difference between this embodiment and Comparative Example 1 is that: Adjustment step (2): Dissolve 0.5 mg BNH6 in 500 μL of ultrapure water to prepare a 1 mg / mL BNH6 aqueous solution, and mix it with SnO2 colloidal aqueous solution at a volume ratio of 2:1. Spin-coat the colloidal aqueous solution onto the treated ITO glass substrate at a speed of 4000 rpm for 30 s, and then anneal it on a hot stage at 150 ℃ for 30 min to form a complex-modified electron transport layer.

[0068] The remaining steps are the same as those in Comparative Example 1.

[0069] Example 3 The difference between this embodiment and Comparative Example 1 is that: Adjustment step (3): FAI (240.76 mg), CsI (18.19 mg), PbI2 (728.40 mg), and MACl (33.08 mg) powders were dissolved in DMF (888 μL) and DMSO (111 μL) and stirred at room temperature for 6 h to form a perovskite precursor solution. This perovskite precursor solution (80 μL) was spin-coated onto the electron transport layer at 1000 rpm for 10 s and then at 5000 rpm for 30 s. 20 s before the end of spin-coating, 800 μL of diethyl ether was rapidly dropped onto the substrate as an antisolvent. The substrate was then annealed for 1 h at 120 °C and 25% RH on a hot plate. 0.5 mg BNH6 was dissolved in 500 μL of isopropanol (IPA) (1 mg / mL). 100 μL of this solution was then spin-coated onto the substrate at 4000 rpm for 30 s to form a complex-modified perovskite layer.

[0070] The remaining steps are the same as those in Comparative Example 1.

[0071] Examples 2 and 3 respectively show the devices prepared with only an electron transport layer and only a perovskite layer, and their performance is compared with that of the device prepared in Example 1 with both an electron transport layer and a perovskite layer modified. The results are shown in Table 2. Figure 12 As shown, it can be seen that the effect of double-layer modification is significantly better than that of single-layer modification.

[0072] Table 2. Comparison of device performance with different modification layers

[0073] In summary, this invention achieves iodine reduction and bilayer optimization by incorporating the multifunctional complex BNH6 into the electron transport layer and on the surface of the perovskite layer. BNH6 not only interacts with SnO2 and the perovskite layer but also prevents I-reduction. - Oxidation and I 0 Restore to I - This improves the efficiency and stability of PSCs. The perovskite solar cells prepared in this way have a high PCE of 25.66% and excellent stability, retaining 90% of the initial PCE after 500 hours of continuous maximum power point tracking.

[0074] The present invention has been described in detail above. For those skilled in the art, the invention can be practiced in a wide range of ways with equivalent parameters, concentrations, and conditions without departing from its spirit and scope, and without requiring unnecessary experiments. Although specific embodiments have been given, it should be understood that further modifications can be made to the invention. In summary, according to the principles of the invention, this application is intended to include any changes, uses, or improvements to the invention, including changes made using conventional techniques known in the art that depart from the scope disclosed herein. Some of the essential features can be applied within the scope of the following appended claims.

Claims

1. A multifunctional complex-modified perovskite solar cell, the structure of which comprises, from bottom to top: The material comprises a substrate layer, a cathode layer, a complex-modified electron transport layer, a complex-modified perovskite layer, a hole transport layer, and a metal anode layer; wherein the complex is ammonia borane (BNH6).

2. The perovskite solar cell modified with a multifunctional complex according to claim 1, characterized in that: The substrate is transparent glass. And / or, the cathode layer is an ITO layer, And / or, the electron transport layer modified by the complex is a tin dioxide (SnO2) layer modified with ammonia borane. And / or, the complex-modified perovskite layer is an ammonia-borane-modified perovskite layer. And / or, the hole transport layer is a 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) layer. And / or, the metal anode layer is gold (Au).

3. The perovskite solar cell modified with a multifunctional complex according to claim 1 or 2, characterized in that: The perovskite is Cs 0.05 FA 0.95 PbI3 perovskite.

4. The perovskite solar cell modified with a multifunctional complex according to any one of claims 1-3, characterized in that: The thickness of the complex-modified electron transport layer is 20-30 nm, the thickness of the complex-modified perovskite layer is 600-700 nm, the thickness of the hole transport layer is 90-120 nm, and the thickness of the metal anode layer is 80-100 nm.

5. A method for preparing a perovskite solar cell modified with a multifunctional complex according to any one of claims 1-4, comprising the following steps: (1) A complex-modified electron transport layer is prepared on a substrate with a cathode layer; (2) Prepare a complex-modified perovskite layer on a complex-modified electron transport layer; (3) A hole transport layer is prepared on the complex-modified perovskite layer; (4) A metal electrode is prepared on the hole transport layer to obtain the perovskite solar cell modified by the multifunctional complex.

6. The preparation method according to claim 5, characterized in that: In step (1), an ammonia borane-modified tin dioxide (SnO2) layer is prepared on a substrate with a cathode layer. The specific preparation method is as follows: BNH6 aqueous solution is mixed with SnO2 colloidal aqueous solution to obtain SnO2 colloidal aqueous solution containing BNH6, and the SnO2 colloidal aqueous solution containing BNH6 is spin-coated on a substrate with a cathode layer and annealed to form a complex-modified electron transport layer. Preferably, the annealing temperature is 100~180℃ and the annealing time is 0.5~1.5h.

7. The preparation method according to claim 5 or 6, characterized in that: In step (2), the method for preparing a complex-modified perovskite layer on a complex-modified electron transport layer includes the following steps: Cs 0.05 FA 0.95 A PbI3 perovskite precursor solution was spin-coated onto a complex-modified electron transport layer. Before the spin-coating was completed, diethyl ether, the antisolvent, was dropped onto the substrate, followed by annealing to form a perovskite film. The isopropanol solution of BNH6 is then spin-coated onto the perovskite film to form a complex-modified perovskite layer.

8. The preparation method according to claim 7, characterized in that: The Cs 0.05 FA 0.95 The preparation method of PbI3 perovskite precursor solution is as follows: Formamidinium hydroiodate (FAI), CsI, PbI2 and methylammonium chloride (MACl) are dissolved in a solvent in a mass ratio of 13:1:40:1.8, and stirred overnight at room temperature to form CsI3 perovskite precursor solution. 0.05 FA 0.95 PbI3 perovskite precursor solution; wherein the solvent is a mixed solvent obtained by mixing DMF and DMSO in a volume ratio of 4:1 to 10:1; And / or, the antisolvent diethyl ether is added 10-20 s before the end of spin coating; And / or, the annealing temperature is 100~150℃, and the annealing time is 0.5~1.5h.

9. The preparation method according to any one of claims 5-8, characterized in that: After step (2) and before step (3), there is also a step of passivating the complex-modified perovskite layer prepared in step (2), specifically as follows: spin-coating the MeO-PEAI solution onto the complex-modified perovskite layer, and then annealing at 100 °C for 5 min to passivate the complex-modified perovskite layer.

10. The preparation method according to any one of claims 5-9, characterized in that: In step (3), the hole transport layer is a 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD) layer. The specific preparation method of the hole transport layer is as follows: a Spiro-OMeTAD mixed solution is spin-coated onto a perovskite layer modified with a complex to form a Spiro-OMeTAD hole transport layer. And / or, in step (4), a metal electrode is prepared on the hole transport layer by vacuum evaporation.

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