Van der Waals material and polymer synergistically enhanced perovskite solar cell

Abstract

The invention discloses a Van der Waals material and polymer synergistically enhanced perovskite solar cell. The perovskite solar cell structurally comprises a conductive substrate layer, a hole transport layer, a perovskite light absorption layer, a polymer layer, a Van der Waals material monomolecular layer, an electron transport layer, a hole barrier layer and a back electrode from bottom to top in sequence, according to the Van der Waals material and polymer synergistically enhanced perovskite solar cell prepared by the invention, through the synergistic effect of the Van der Waals material and polymer double-layer structure, the photo-induced perovskite lattice expansion is significantly inhibited, and the stress damage of a crystal boundary region is reduced; meanwhile, the double-layer structure effectively obstructs diffusion of halide ions and provides a physical protection barrier for the perovskite thin film, so that efficient and stable preparation of the perovskite solar cell is realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic chemistry, and specifically relates to a van der Waals material and polymer co-enhanced perovskite solar cell. Background Art

[0002] Perovskite solar cells (PSCs) have become a research hotspot in the photovoltaic field due to their high power conversion efficiency (PCE) and low-cost fabrication process. Currently, the laboratory-certified efficiency of PSCs has reached 27%, approaching the level of single-crystalline silicon solar cells. However, the practical application of PSCs is severely limited by their insufficient operational stability. Although significant progress has been made in improving the stability of PSCs through strategies such as compositional engineering, interface design, and defect passivation in recent years, their working lifetime is still far lower than that of traditional crystalline silicon solar cells. Crystalline silicon solar cells can ensure an annual efficiency loss of less than 0.5% within 20 years, while the degradation problems of PSCs under actual environmental conditions such as light illumination, humidity, and heat have not been effectively solved.

[0003] The root cause of the instability problem of PSCs lies in the soft ionic characteristics of hybrid perovskite materials. This characteristic leads to significant phenomena such as photoinduced strain, electrostriction response, flexoelectricity, anharmonic vibration, and large polaron formation. For example, FA 0.7 MA 0.25 Cs 0.05 PbI 3 After 180 minutes of one-sun illumination, the lattice of the perovskite thin film expands isotropically by about 0.63%, while the lattice change rate of crystalline silicon materials under the same conditions is less than 0.001%. Although the stimulus-induced lattice dynamics has potential advantages in device performance regulation, the lattice deformation and structural evolution it causes will further accelerate device degradation.

[0004] In response to the above problems, the existing technologies mainly focus on chemical composition optimization and interface modification, etc., but the research on the mechanical stability of the perovskite lattice is still relatively limited. The lattice expansion and deformation of the perovskite thin film under light illumination and thermal stress will lead to grain boundary damage, increased ion migration, and rapid decay of device performance. Therefore, developing an interface structure that can effectively inhibit the dynamic deformation of the perovskite lattice and enhance its mechanical stability is of great significance for improving the long-term operational stability of PSCs. Summary of the Invention

[0005] The purpose of the present invention is to provide a van der Waals material and polymer co-enhanced perovskite solar cell.

[0006] Another purpose of the present invention is to provide a preparation method for the van der Waals material and polymer co-enhanced perovskite solar cell.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] In the first aspect of the present invention, a van der Waals material and polymer synergistically enhanced perovskite solar cell is provided, and the structure from bottom to top is successively: a conductive base layer, a hole transport layer, a perovskite light absorption layer, a polymer layer, a van der Waals material monolayer, an electron transport layer, a hole blocking layer, and a back electrode;

[0009] The material of the conductive base layer is selected from FTO conductive glass or ITO conductive glass;

[0010] The material of the hole transport layer is selected from [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz), [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphoric acid (MeO-2PACz), poly(3,4-ethylenedioxythiophene) (PEDOT:PSS), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)]amine (PTAA), etc.;

[0011] The material of the perovskite light absorption layer is selected from Cs x FA y MA 1-x-y Pb(I z Br 1-z ) 3 , where x is 0 to 1, y is 0 to 1, and z is 0 to 1; CH 3 NH 3 PbI 3 (MAPbI 3 ); MAPb x Sn 1-x I 3 , where x is 0 to 1; CH(NH 2 ) 2 PbI 3 (FAPbI 3 ); FAPb x Sn 1- x I 3 , where x is 0 to 1; Cs x MA 1-x Pb(I y Br 1-y ) 3 , where x is 0 to 1, y is 0 to 1; Cs x FA 1-x Pb(I y Br 1-y ) 3 , where x is 0 to 1; y is 0 to 1; FA x MA 1-x Pb(Iy Br 1-y ) 3 where x ranges from 0 to 1; y ranges from 0 to 1; CsPb(I x Br 1-x ) 3 where x ranges from 0 to 1; CsSn(I x Br 1-x ) 3 where x ranges from 0 to 1; (PEA) 2 (MA) n-1 Pb n I 3n+1 where n is an integer starting from 1 (such as 1, 2, 3, 4, 5). Preferably Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 ;

[0012] The material of the polymer layer is selected from polyaniline, polypyrrole, polydimethylsiloxane, polyurethane, polyvinyl alcohol, polycarbonate, polymethyl methacrylate, polylactic acid, polycaprolactone, polyethylene glycol, polytetrafluoroethylene, polyether ether ketone, polyimide, chitosan;

[0013] The material of the van der Waals material monolayer is selected from boron nitride, black phosphorus, molybdenum disulfide, molybdenum diselenide, tungsten disulfide, graphene.

[0014] The thickness of the substrate in the conductive substrate is 1 - 2 mm (preferably 1 mm), and the thickness of the conductive layer is 200 - 600 nm (preferably 300 nm).

[0015] The parameters of the ITO conductive glass: 8 Ω / m 2 、length × width = 1.5 cm × 1.3 cm.

[0016] The material of the electron transport layer is selected from [6,6]-phenyl-C 61 -butyric acid methyl ester ([6,6]-Phenyl-C 61 -butyric acid methyl ester, PC 61 BM).

[0017] The material of the hole blocking layer is selected from 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (Bathocuproine, BCP).

[0018] The material of the back electrode is selected from silver.

[0019] The Cs x FA y MA1-x-y Pb(I z Br 1-z ) 3 , wherein x is from 0 to 1, y is from 0 to 1, and z is from 0 to 1. The method for preparing the solution comprises the following steps:

[0020] Dissolve cesium iodide, methylammonium bromide, lead bromide, formamidinium hydroiodide, and lead iodide powders with a molar ratio of 1:1 - 5:0.05 - 5:1 - 30:1 - 30 (preferably 1:2:3.1:16.2:16.9, 1:2:0.1:16.2:19.9) in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide. The volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 2 - 8:1 (preferably 4:1), and stir overnight at room temperature to obtain the solution of Cs x FA y MA 1-x-y Pb(I z Br 1-z ) 3 .

[0021] The method for preparing the Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 perovskite precursor solution comprises the following steps:

[0022] Dissolve cesium iodide, methylammonium bromide, lead bromide, formamidinium hydroiodide, and lead iodide powders with a molar ratio of 1:2:3.1:16.2:16.9 in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide. The volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 2 - 8:1 (preferably 4:1), and stir overnight at room temperature to obtain the solution of Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 .

[0023] The thickness of the hole transport layer is 10 - 50 nm (preferably 20 nm).

[0024] The thickness of the perovskite light-absorbing layer is 500 - 1500 nm (preferably 550 nm).

[0025] The thickness of the polymer layer is 1 - 20 nm (preferably 4 nm).

[0026] The thickness of the van der Waals material monolayer is 0.33 nm.

[0027] The thickness of the electron transport layer is 20 nm.

[0028] The thickness of the hole blocking layer is 5 nm.

[0029] The thickness of the back electrode is 100 nm.

[0030] In the second aspect of the present invention, a preparation method of a van der Waals material and polymer synergistically enhanced perovskite solar cell is provided, including the following steps:

[0031] In the first step, a hole transport layer material solution is spin-coated on the surface of a clean conductive substrate layer, and this layer serves as the hole transport layer;

[0032] In the second step, a perovskite precursor solution is spin-coated on the hole transport layer prepared above to form a perovskite light-absorbing layer thin film, which is completed in a nitrogen glove box, and this layer serves as the perovskite light-absorbing layer;

[0033] In the third step, a polymer solution is spin-coated on the surface of the perovskite light-absorbing layer to form a polymer thin film, and this layer serves as the polymer layer;

[0034] In the fourth step, a van der Waals material is covered above the polymer layer to form a stable van der Waals material-polymer bilayer structure, and this layer serves as the van der Waals material monolayer;

[0035] In the fifth step, an electron transport layer material solution is spin-coated on the surface of the van der Waals material monolayer, and this layer serves as the electron transport layer;

[0036] In the sixth step, a hole blocking layer material solution is spin-coated on the surface of the electron transport layer, and this layer serves as the hole blocking layer;

[0037] In the seventh step, metallic silver is evaporated on the hole blocking layer to serve as the back electrode.

[0038] The cleaning steps of the conductive substrate layer are as follows:

[0039] The conductive substrate is successively ultrasonically cleaned three times with deionized water, acetone, and ethanol, and then dried until the solvent and moisture are completely removed;

[0040] The cleaned conductive substrate is dried and treated with ultraviolet ozone for 10 - 30 min (preferably 20 min), and this layer serves as the conductive substrate layer.

[0041] The parameters of the spin-coating in the first step are: 3000 rpm, 30 s, and annealing is carried out at a temperature of 80 - 130 °C (preferably 100 °C) for 3 - 20 min (preferably 10 min).

[0042] The parameters for the second spin coating are: 1000 rpm, 5 s, 4000 rpm, 20 s; heating is carried out at a temperature of 80 - 130 °C (preferably 100 °C) for 5 - 40 min (preferably 30 min).

[0043] The parameters for the spin coating in the third step are: 3000 rpm, 30 s; heating is carried out at a temperature of 90 - 110 °C (preferably 100 °C) for 5 - 15 min (10 min).

[0044] The conditions for forming a stable van der Waals material polymer bilayer structure in the fourth step are: heating is carried out at a temperature of 90 - 110 °C (preferably 105 °C) for 3 - 8 min (preferably 5 min).

[0045] The parameters for the spin coating in the fifth step are: 2000 rpm, 45 s.

[0046] The parameters for the spin coating in the sixth step are: 4000 rpm, 45 s; heating is carried out at a temperature of 60 - 90 °C (preferably 70 °C) for 5 - 20 min (preferably 15 min).

[0047] In the first step, the preparation method of the hole transport layer material solution is: dissolving the material of the hole transport layer in absolute ethanol to form a hole transport layer material solution with a concentration of 0.1 - 1 mg / mL (preferably a concentration of 0.3 mg / mL).

[0048] In the third step, the preparation method of the polymer solution is: dissolving the material of the polymer layer in an organic reagent (preferably acetone) to form a polymer solution with a concentration of 0.05 - 20 mg / mL (preferably a concentration of 0.2 mg / mL).

[0049] The organic reagent is selected from chloroform, dichloromethane, ethyl acetate, acetone, n - hexane, benzene, chlorobenzene.

[0050] In the fifth step, the preparation method of the electron transport layer material solution is:

[0051] Dissolving the material of the electron transport layer in chlorobenzene and stirring at room temperature for at least 24 h to obtain the electron transport layer material solution.

[0052] In the sixth step, the preparation method of the hole blocking layer material solution is:

[0053] Dissolving the material of the hole blocking layer in absolute ethanol and stirring at room temperature for at least 24 h to obtain the hole blocking layer material solution.

[0054] Due to the adoption of the above - mentioned technical solution, the present invention has the following advantages and beneficial effects:

[0055] The van der Waals material and polymer co-enhanced perovskite solar cell prepared by the present invention achieves a power conversion efficiency (PCE) of over 24%. After 3070 hours of maximum power point (MPP) operation under simulated AM 1.5 G illumination and at 90 °C, it still maintains over 95% of its initial efficiency. The excellent durability of this mechanically enhanced device indicates that the van der Waals material and polymer co-enhanced perovskite solar cell prepared by the present invention has the potential to meet the industrial standards for large-scale applications.

[0056] The van der Waals material and polymer co-enhanced perovskite solar cell prepared by the present invention, through the synergistic effect of the van der Waals material and polymer bilayer structure, significantly inhibits the photoinduced perovskite lattice expansion and reduces the stress damage in the grain boundary region. At the same time, this bilayer structure effectively blocks the diffusion of halogen ions and provides a physical protection barrier for the perovskite film, thus realizing the preparation of highly efficient and stable perovskite solar cells.

[0057] The van der Waals material and polymer co-enhanced perovskite solar cell prepared by the present invention is a novel mechanically tough interfacial structure. Through the synergistic effect of the van der Waals material and the polymer, it significantly inhibits the photoinduced lattice expansion of the perovskite film, reduces grain boundary damage, and inhibits the lateral diffusion of halogen ions.

[0058] The present invention adopts simple mixing coating or layer-by-layer coating methods, making the preparation process simple and economical, thus reducing the production cost.

[0059] In the van der Waals material and polymer co-enhanced perovskite solar cell prepared by the present invention, the perovskite absorption layer is applicable to various different types of perovskite layers, such as CH 3 NH 3 PbI 3 、MAPb x Sn 1-x I 3 、Cs x FA y MA 1-x-y Pb(I z Br 1-z ) 3 and so on, with wide applicability.

[0060] Both the polymer and the van der Waals material used in the present invention are commercial products, without the need for further treatment, and have high practicality and operability. Brief Description of the Drawings

[0061] Figure 1 It is a schematic diagram of the I 3d core level XPS spectrum of the perovskite absorption layer film prepared in Example 1 and Comparative Example 1.

[0062] Figure 2 Schematic diagram of X-ray diffraction spectrum data of the perovskite light-absorbing layer films prepared in Example 1 and Comparative Example 1 after being aged under light for different times.

[0063] Figure 3 Schematic diagram of in-situ XRD evolution data of the perovskite light-absorbing layer films prepared in Example 1 and Comparative Example 1 under ultraviolet light irradiation.

[0064] Figure 4 Schematic diagram of the temperature-dependent conductivity results of the perovskite solar cells prepared in Example 1 and Comparative Example 1.

[0065] Figure 5 Schematic diagram of the current density-voltage curve obtained in the reverse scan mode of the perovskite solar cell prepared in Example 1.

[0066] Figure 6 Schematic diagram of the evaluation result of the long-term operation stability of the perovskite solar cell prepared in Example 1 by tracking its maximum power point under continuous one-sun illumination at 90 °C.

[0067] Figure 7 Schematic diagram of the atomic structure of the van der Waals material boron nitride in Example 1. Detailed implementation manners

[0068] To illustrate the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments. Those skilled in the art should understand that the specific content described below is illustrative rather than restrictive, and should not be used to limit the protection scope of the present invention.

[0069] Example 1

[0070] The first step: Preparation of the polymer solution

[0071] Dissolve polyurethane (2×10 -8 mol, 0.2 mg, PU-90) in 1 mL of acetone, and stir overnight at a temperature of 70 °C to obtain a polymer solution with a concentration of 0.2 mg / mL.

[0072] The second step: Preparation of the perovskite precursor solution and the charge transport layer material solution

[0073] Preparation of the hole transport layer material solution:

[0074] Dissolve 2PACz (1.1×10 -6 mol, 0.3 mg) in 1 mL of absolute ethanol, and stir overnight to obtain a 2PACz solution with a concentration of 0.3 mg / mL.

[0075] Preparation of perovskite precursor solution:

[0076] Dissolve cesium iodide (0.07 mol, 18.2 mg), methylammonium bromide (0.14 mol, 21.9 mg), lead bromide (0.217 mol, 79.6 mg), formamidinium hydroiodide (1.134 mol, 195.1 mg), and lead iodide powder (1.183 mol, 545.4 mg) in 1 mL of a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide (the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 4:1), and stir overnight at room temperature to obtain a Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 perovskite precursor solution with a concentration of 1.4 mol / L.

[0077] Preparation of electron transport layer material solution:

[0078] Use [6,6]-phenyl-C 61 -butyric acid methylester ([6,6]-Phenyl-C 61 -butyric acid methylester, PC 61 BM) as the electron transport layer material.

[0079] Dissolve PC 61 BM (2×10 -5 mol, 20 mg) in 1 mL of chlorobenzene and stir for 24 h at room temperature to obtain a PC 61 BM solution, which is the electron transport layer material solution.

[0080] Dissolve 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (Bathocuproine, BCP) (1×10 -6 mol, 0.5 mg) in 1 mL of absolute ethanol and stir for 24 h at room temperature to obtain a BCP solution, which is the hole blocking layer material solution.

[0081] Third step, preparation of van der Waals material and polymer co-enhanced perovskite solar cells

[0082] The cleaning steps of the conductive substrate are as follows: ultrasonically clean the conductive substrate three times successively with deionized water, acetone, and ethanol, and then dry it until all solvents and moisture are completely removed.

[0083] The cleaned ITO conductive glass (Nippon Sheet Glass, Wuhan Lattice Solar Technology Co., Ltd., 8 , with a length × width of 1.5 cm × 1.3 cm, a glass substrate thickness of 1 mm, and a conductive layer thickness of 300 nm) was dried and treated with an ultraviolet ozone cleaner for 20 min. This layer serves as the conductive glass substrate layer.

[0084] The hole transport layer material solution, 2PACz solution, was spin-coated on the clean ITO surface. The spin-coating parameters were: 3000 rpm, 30 s, and annealed by heating at 100 °C for 10 min, with a thickness of 20 nm. This layer serves as the hole transport layer.

[0085] 50 μL of Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 The perovskite precursor solution was spin-coated on the hole transport layer prepared above. The spin-coating parameters were: 1000 rpm, 5 s, 4000 rpm, 20 s; and heated at 100 °C for 30 min to form a perovskite light-absorbing layer film. The preparation of the perovskite absorption layer film was completed in a nitrogen glove box, with a thickness of 550 nm. This layer serves as the perovskite light-absorbing layer.

[0086] Polymer, i.e., polyurethane solution, was spin-coated on the surface of the perovskite light-absorbing layer. The spin-coating parameters were: 3000 rpm, 30 s; and heated at 100 °C for 10 min to form a polymer film, with a thickness of 4 nm. This layer serves as the polymer layer.

[0087] The van der Waals material, i.e., boron nitride, was covered above the polymer layer and heated at 105 °C for 5 min to make the van der Waals material in close contact with the polymer, forming a stable van der Waals material-polymer bilayer structure, with a thickness of 0.33 nm. This layer serves as the van der Waals material monolayer.

[0088] On the surface of the van der Waals material monolayer, the electron transport layer material solution, i.e., PC 61 BM solution, was spin-coated. The spin-coating parameters were: 2000 rpm, 45 s; and the thickness was 20 nm. This layer serves as the electron transport layer.

[0089] On the surface of the electron transport layer, the hole blocking layer material, i.e., BCP solution, was spin-coated. The spin-coating parameters were: 4000 rpm, 45 s; and heated at 70 °C for 15 min, with a thickness of 5 nm. This layer serves as the hole blocking layer.

[0090] Using an evaporation coater, metallic silver was evaporated on the hole blocking layer, with a thickness of 100 nm, serving as the back electrode.

[0091] The prepared van der Waals material and polymer co-enhanced perovskite solar cell has the following structure from bottom to top: a conductive glass substrate layer, a hole transport layer, a perovskite light-absorbing layer, a polymer layer, a van der Waals material monolayer, an electron transport layer, a hole blocking layer, and a back electrode. Among them, the thickness of the glass substrate is 1 mm, the thickness of the conductive layer is 300 nm, the thickness of the hole transport layer is 20 nm, the thickness of the perovskite light-absorbing layer is 550 nm, the thickness of the polymer layer is 4 nm, the thickness of the van der Waals material monolayer is 0.33 nm, the thickness of the electron transport layer is 20 nm, the thickness of the hole blocking layer is 5 nm, and the thickness of the back electrode is 100 nm.

[0092] Comparative Example 1

[0093] Preparation of perovskite solar cells:

[0094] The cleaned ITO conductive glass (Wuhan Lattice Solar Technology Co., Ltd., 8 , length × width = 1.5 cm × 1.3 cm, glass substrate thickness of 1 mm, conductive layer thickness of 300 nm) was dried and treated with an ultraviolet ozone cleaning machine for 20 min, and this layer was used as the conductive glass substrate layer.

[0095] The hole transport layer material solution, 2PACz solution, was spin-coated on the clean ITO surface. The spin-coating parameters were: 3000 rpm, 30 s, and annealed at 100 °C for 10 min. The thickness was 20 nm, and this layer was used as the hole transport layer.

[0096] 50 μL of Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 The perovskite precursor solution was spin-coated on the above-prepared hole transport layer. The spin-coating parameters were: 1000 rpm, 5 s, 4000 rpm, 20 s; and heated at 100 °C for 30 min to form a perovskite light-absorbing layer thin film. The preparation of the perovskite absorption layer thin film was completed in a nitrogen glove box. The thickness was 550 nm, and this layer was used as the perovskite light-absorbing layer.

[0097] The electron transport layer material solution, PC 61 BM solution, was spin-coated on the surface of the perovskite light-absorbing layer. The spin-coating parameters were: 2000 rpm, 45 s; and the thickness was 20 nm, and this layer was used as the electron transport layer.

[0098] The hole blocking layer material, BCP solution, was spin-coated on the surface of the electron transport layer. The spin-coating parameters were: 4000 rpm, 45 s; and heated at 70 °C for 15 min. The thickness was 5 nm, and this layer was used as the hole blocking layer.

[0099] The metal silver was evaporated on the hole blocking layer by an evaporation coater with a thickness of 100 nm as the back electrode.

[0100] For the prepared perovskite solar cell, the structure from bottom to top is successively: a conductive glass substrate layer, a hole transport layer, a perovskite light absorption layer, an electron transport layer, a hole blocking layer, and a back electrode. Among them, the thickness of the glass substrate is 1 mm, the thickness of the conductive layer is 300 nm, the thickness of the hole transport layer is 20 nm, the thickness of the perovskite light absorption layer is 550 nm, the thickness of the electron transport layer is 20 nm, the thickness of the hole blocking layer is 5 nm, and the thickness of the back electrode is 100 nm.

[0101] Figure 1 It is a schematic diagram of the I 3d core level XPS spectrum of the perovskite absorption layer film prepared in Example 1 and Comparative Example 1. It can be seen from the figure that there is a shift in the binding energy, and the shift in the binding energy indicates that the amide group in the polyurethane has a coordination effect with the iodide ions on the perovskite surface.

[0102] Figure 2 It is a schematic diagram of the X-ray diffraction spectrum (XRD) data of the perovskite light absorption layer film prepared in Example 1 and Comparative Example 1 after being aged under light ( ). It can be seen from the figure that the comparative sample was prepared in Comparative Example 1, and the test sample was prepared in Example 1. After being aged under light, the (001) diffraction peak of the comparative sample prepared shifted to the left by (as shown in a in Figure 2 ), indicating that the perovskite lattice expanded, while the (001) diffraction peak of the experimental sample (the sample containing the van der Waals material polymer bilayer structure) showed almost no shift before and after light irradiation ( Figure 2 as shown in b in

[0103] Figure 3 It is a schematic diagram of the in-situ XRD evolution data of the perovskite light absorption layer film prepared in Example 1 and Comparative Example 1 under ultraviolet light irradiation, which can more intuitively observe the dynamic expansion and deformation process of the perovskite lattice under light conditions. This figure shows the evolution process of the XRD (001) and (002) diffraction peaks of the perovskite light absorption layer film under ultraviolet light irradiation conditions. The comparative sample was prepared in Comparative Example 1, and the test sample was prepared in Example 1. a is the result of the comparative sample, and b is the result of the test sample. From Figure 3 a, it can be obtained that after 50 min of light irradiation, the (001) diffraction peak of the comparative sample shifted 0.02° to a lower angle, corresponding to an expansion rate of 0.15%; the (002) diffraction peak shifted 0.04° to a lower angle, corresponding to an expansion rate of 0.14%. From Figure 3From b, it can be obtained that the swelling rates of the (001) and (002) diffraction peaks of the experimental samples are both 0.07%. The results show that the van der Waals material polymer bilayer structure reduces the swelling rate of the perovskite lattice under ultraviolet light illumination.

[0104] Figure 4 It is a schematic diagram of the temperature-dependent conductivity results of the perovskite solar cells prepared in Example 1 and Comparative Example 1. The comparative sample was prepared in Comparative Example 1, and the test sample was prepared in Example 1. a is the result of the comparative sample, and b is the result of the test sample. As can be seen from the figure, in the comparative sample, when the temperature rises to 317 K, the ionic conductivity becomes the dominant mechanism, and its activation energy (E a ) is 0.305 eV; while the threshold temperature of the experimental sample is increased to 331 K, and at the same time, due to the passivation effect, E a increases to 0.507 eV. The results show that the van der Waals material polymer bilayer structure effectively blocks the diffusion of halogen ions in the perovskite solar cells.

[0105] Performance characterization test of the perovskite solar cell prepared in Example 1 of the present invention

[0106] The assembled perovskite solar cell was irradiated by a solar simulator under standard light to test the photoelectric conversion efficiency. The effective area of the cell is 0.0625 cm 2 . Figure 5 It is a schematic diagram of the current density-voltage (J-V) curve obtained in the reverse scan mode of the perovskite solar cell prepared in Example 1, and the photoelectric conversion efficiency is 24.04%.

[0107] The photoelectric conversion efficiency (power conversion efficiency, PCE) is the most basic and core parameter for evaluating solar cells, and it can be calculated from the current-voltage (I-V) curve measured by the cell under the standard solar irradiance conditions of AM 1.5G. The calculation formula is as follows:

[0108]

[0109] Among them, P in represents the intensity of incident light. J SC is the short-circuit photocurrent density, that is, the current density when the circuit is in the short-circuit state, and the cell voltage is 0 V at this time. V OCis the open-circuit photovoltage, which is the potential difference across the battery measured when the battery is in an open-circuit state. At this moment, the current flowing through the circuit is 0 A. FF is the fill factor, which is obtained by dividing the maximum power per unit area of the solar cell (P max ) by the ratio of V OC and J SC and ranges from 0 to 1, as shown in Equation (1.2).

[0110]

[0111] The photoelectric conversion efficiency is the most important parameter for evaluating the performance of solar cells. Before testing, a solar simulator (Solar IV-150A, Zolix) was used to simulate a standard sunlight AM 1.5G ( ) as the light source to illuminate and test the solar cell. Before use, a standard Newport-calibrated KG5-filtered silicon reference cell was used to calibrate the light intensity. In a conventional working environment, a Keithley 2400 digital source meter was used to measure the J-V curve of the device at a scanning rate (the voltage scanning range was from -0.2 to 1.3 V, with a step size of 10 mV). The effective area of the device was limited to 0.0625 cm 2 using a metal mask template.

[0112] Figure 6 shows the long-term operating stability of the perovskite solar cell prepared in Example 1. The evaluation results were obtained by tracking its maximum power point (MPP) under continuous one-sun illumination at 90°C. It can be seen from the graph that after 3070 hours of continuous operation, the perovskite solar cell prepared in Example 1 can maintain more than 95% of its initial efficiency.

[0113] Figure 7 shows the atomic structure diagram of the van der Waals material boron nitride in Example 1. It can be seen from the figure that the single-layer atomic structure of boron nitride is a typical van der Waals material.

[0114] Comparative Example 2

[0115] First step: Preparation of the polymer solution

[0116] Dissolve polyurethane (2×10 -8 mol, 0.2 mg, PU-90) in 1 mL of acetone and stir overnight at 70°C to obtain a polymer solution with a concentration of 0.2 mg / mL.

[0117] Second step: Preparation of the perovskite precursor solution and the charge transport layer material solution

[0118] Preparation of hole transport layer material solution:

[0119] Dissolve 2PACz (1.1×10 -6 mol, 0.3 mg) in 1 mL of absolute ethanol and stir overnight to obtain a 2PACz solution with a concentration of 0.3 mg / mL;

[0120] Preparation of perovskite precursor solution:

[0121] Dissolve cesium iodide (0.07 mol, 18.2 mg), methylammonium bromide (0.14 mol, 21.9 mg), lead bromide (0.217 mol, 79.6 mg), formamidinium hydroiodide (1.134 mol, 195.1 mg), and lead iodide powder (1.183 mol, 545.4 mg) in 1 mL of a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide (the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 4:1), and stir overnight at room temperature to obtain a Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 perovskite precursor solution.

[0122] Preparation of electron transport layer material solution:

[0123] Use PC 61 BM as the electron transport layer material.

[0124] Dissolve PC 61 BM (2×10 -5 mol, 20 mg) in 1 mL of chlorobenzene and stir at room temperature for 24 h to obtain a PC 61 BM solution, which is the electron transport layer material solution.

[0125] Dissolve BCP (1×10 -6 mol, 0.5 mg) in 1 mL of absolute ethanol and stir at room temperature for 24 h to obtain a BCP solution, which is the hole blocking layer material solution.

[0126] Third step, preparation of van der Waals material and polymer co-enhanced perovskite solar cells

[0127] Dry the cleaned ITO conductive glass (Wuhan Lattice Solar Technology Co., Ltd., 8 , length×width = 1.5 cm×1.3 cm, glass substrate thickness is 1 mm, conductive layer thickness is 300 nm), and treat it with an ultraviolet ozone cleaner for 20 min. This layer serves as the conductive glass base layer.

[0128] The hole transporting layer material solution, 2PACz solution, was spin-coated on the clean ITO surface. The spin-coating parameters were: 3000 rpm, 30 s, and it was annealed by heating at 100 °C for 10 min, with a thickness of 20 nm. This layer served as the hole transporting layer.

[0129] 50 μL of Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 The perovskite precursor solution was spin-coated on the hole transporting layer prepared above. The spin-coating parameters were: 1000 rpm, 5 s, 4000 rpm, 20 s; and it was heated at 100 °C for 30 min to form a perovskite light-absorbing layer thin film. The preparation of the perovskite absorption layer thin film was completed in a nitrogen glove box, with a thickness of 550 nm. This layer served as the perovskite light-absorbing layer.

[0130] A polymer, i.e., polyurethane solution, was spin-coated on the surface of the perovskite light-absorbing layer. The spin-coating parameters were: 3000 rpm, 30 s; and it was heated at 100 °C for 10 min to form a polymer thin film, with a thickness of 4 nm. This layer served as the polymer layer.

[0131] A solution of the electron transporting layer material, i.e., PC 61 BM solution, was spin-coated on the surface of the polymer layer. The spin-coating parameters were: 2000 rpm, 45 s; and the thickness was 20 nm. This layer served as the electron transporting layer.

[0132] A solution of the hole blocking layer material, i.e., BCP solution, was spin-coated on the surface of the electron transporting layer. The spin-coating parameters were: 4000 rpm, 45 s; and it was heated at 70 °C for 15 min, with a thickness of 5 nm. This layer served as the hole blocking layer.

[0133] Metallic silver was evaporated on the hole blocking layer using an evaporation instrument, with a thickness of 100 nm, serving as the back electrode.

[0134] The prepared perovskite solar cell had a structure from bottom to top as follows: conductive glass substrate layer, hole transporting layer, perovskite light-absorbing layer, polymer layer, electron transporting layer, hole blocking layer, back electrode. Among them, the glass substrate had a thickness of 1 mm, the conductive layer had a thickness of 300 nm, the hole transporting layer had a thickness of 20 nm, the perovskite light-absorbing layer had a thickness of 550 nm, the polymer layer had a thickness of 4 nm, the electron transporting layer had a thickness of 20 nm, the hole blocking layer had a thickness of 5 nm, and the back electrode had a thickness of 100 nm.

[0135] Comparative Example 3

[0136] Step 1: Preparation of perovskite precursor solution and charge transport layer material solution

[0137] Preparation of hole transport layer material solution:

[0138] Dissolve 2PACz (1.1×10 -6 mol, 0.3 mg) in 1 mL of absolute ethanol and stir overnight to obtain a 2PACz solution with a concentration of 0.3 mg / mL.

[0139] Preparation of perovskite precursor solution:

[0140] Dissolve cesium iodide (0.07 mol, 18.2 mg), methylammonium bromide (0.14 mol, 21.9 mg), lead bromide (0.217 mol, 79.6 mg), formamidinium hydroiodide (1.134 mol, 195.1 mg), and lead iodide powder (1.183 mol, 545.4 mg) in 1 mL of a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide (the volume ratio of N,N-dimethylformamide to dimethyl sulfoxide is 4:1), and stir overnight at room temperature to obtain a Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 perovskite precursor solution.

[0141] Preparation of electron transport layer material solution:

[0142] Use PC 61 BM as the electron transport layer material.

[0143] Dissolve PC 61 BM (2×10 -5 mol, 20 mg) in 1 mL of chlorobenzene and stir at room temperature for 24 h to obtain a PC 61 BM solution, which is the electron transport layer material solution.

[0144] Dissolve BCP (1×10 -6 mol, 0.5 mg) in 1 mL of absolute ethanol and stir at room temperature for 24 h to obtain a BCP solution, which is the hole blocking layer material solution.

[0145] Step 2: Fabrication of perovskite solar cells

[0146] The cleaned ITO conductive glass (Wuhan Lattice Solar Technology Co., Ltd., 8 , with length × width = 1.5 cm × 1.3 cm, the thickness of the glass substrate is 1 mm, and the thickness of the conductive layer is 300 nm), dried, and treated with an ultraviolet ozone cleaning machine for 20 min. This layer serves as the conductive glass substrate layer.

[0147] Spin-coat the hole transport layer material solution, 2PACz solution, on the clean ITO surface. The spin-coating parameters are: 3000 rpm, 30 s, and anneal at 100 °C for 10 min. The thickness is 20 nm, and this layer serves as the hole transport layer.

[0148] Add 50 μL of Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 Spin-coat the perovskite precursor solution on the hole transport layer prepared above. The spin-coating parameters are: 1000 rpm, 5 s, 4000 rpm, 20 s; heat at 100 °C for 30 min to form a perovskite light-absorbing layer thin film. The preparation of the perovskite absorption layer thin film is completed in a nitrogen glove box. The thickness is 550 nm, and this layer serves as the perovskite light-absorbing layer.

[0149] Cover the perovskite light-absorbing layer with the van der Waals material, boron nitride, and heat at 105 °C for 5 min to make the van der Waals material closely contact with the perovskite light-absorbing layer. The thickness is 0.33 nm, and this layer serves as the van der Waals material monolayer.

[0150] Spin-coat the electron transport layer material solution, PC 61 BM solution, on the surface of the van der Waals material monolayer. The spin-coating parameters are: 2000 rpm, 45 s; the thickness is 20 nm, and this layer serves as the electron transport layer.

[0151] Spin-coat the hole blocking layer material, BCP solution, on the surface of the electron transport layer. The spin-coating parameters are: 4000 rpm, 45 s; heat at 70 °C for 15 min. The thickness is 5 nm, and this layer serves as the hole blocking layer.

[0152] Evaporate metal silver on the hole blocking layer using an evaporation instrument. The thickness is 100 nm, serving as the back electrode.

[0153] The prepared perovskite solar cell has a structure from bottom to top as follows: a conductive glass substrate layer, a hole transport layer, a perovskite light-absorbing layer, a van der Waals material monolayer, an electron transport layer, a hole blocking layer, and a back electrode. Among them, the thickness of the glass substrate is 1 mm, the thickness of the conductive layer is 300 nm, the thickness of the hole transport layer is 20 nm, the thickness of the perovskite light-absorbing layer is 550 nm, the thickness of the van der Waals material monolayer is 0.33 nm, the thickness of the electron transport layer is 20 nm, the thickness of the hole blocking layer is 5 nm, and the thickness of the back electrode is 100 nm.

[0154] Example 2

[0155] Replace the conductive substrate in Example 1 with FTO conductive glass (purchased from Wuhan Lattice Solar Energy Technology Co., Ltd., 14 , length × width = 1.5 cm × 1.3 cm, the thickness of the glass substrate is 2 mm, and the thickness of the conductive layer is 500 nm), and the others are the same as in Example 1.

[0156] Example 3

[0157] Replace the back electrode in Example 1 with metallic copper, and the others are the same as in Example 1.

[0158] The above are only the preferred embodiments of the present invention, and there is no any form of limitation to the present invention. Although the present invention has been disclosed as above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art of this patent can make some changes or modifications to the above-mentioned technical content to make equivalent embodiments of equivalent changes within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the present invention.

Claims

1. A van der Waals material and polymer synergistically enhanced perovskite solar cell, characterized in that: The structure from bottom to top is: conductive substrate layer, hole transport layer, perovskite light absorption layer, polymer layer, van der Waals material monolayer, electron transport layer, hole blocking layer, back electrode; The material of the perovskite light absorbing layer is selected from Cs x FA y MA 1-x-y Pb(I z Br 1-z )3, where x is 0~1, y is 0~1, and z is 0~1; CH3NH3PbI3; MAPb x Sn 1-x I3, where x is 0 to 1; CH(NH2)2PbI3; FAPb x Sn 1-x I3, where x is 0~1; Cs x MA 1- x Pb(I y Br 1-y )3, where x is 0~1, y is 0~1; Cs x FA 1-x Pb(I y Br 1-y )3, where x is 0~1; y is 0~1; FA x MA 1-x Pb(I y Br 1-y )3, where x is 0~1; y is 0~1; CsPb(I x Br 1-x )3, where x is 0~1; CsSn(I x Br 1-x )3, where x is 0~1; (PEA)2(MA) n-1 Pb n I 3n+1 , where n is an integer starting from 1; The material of the polymer layer is selected from polyaniline, polypyrrole, polydimethylsiloxane, polyurethane, polyvinyl alcohol, polycarbonate, polymethyl methacrylate, polylactic acid, polycaprolactone, polyethylene glycol, polytetrafluoroethylene, polyetheretherketone, polyimide, and chitosan; The material of the van der Waals material monolayer is selected from boron nitride, black phosphorus, molybdenum disulfide, molybdenum diselenide, tungsten disulfide, and graphene.

2. The van der Waals material and polymer synergistically enhanced perovskite solar cell according to claim 1, characterized in that: The material of the conductive substrate layer is selected from FTO conductive glass or ITO conductive glass; The material of the hole transport layer is selected from [2-(9H-carbazole-9-yl)ethyl]phosphonic acid, [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid, poly(3,4-ethylenedioxythiophene), and poly[bis(4-phenyl)(2,4,6-trimethylphenyl)]amine.

3. The van der Waals material and polymer synergistically enhanced perovskite solar cell according to claim 1, characterized in that: The material of the electron transport layer is selected from [6,6]-phenyl-C 61 -Methyl butyrate; The material of the hole blocking layer is selected from 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline; The material of the back electrode is selected from silver; The material of the perovskite light absorbing layer is selected from Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 .

4. The van der Waals material and polymer synergistically enhanced perovskite solar cell according to claim 1, characterized in that: The Cs x FA y MA 1-x-y Pb(I z Br 1-z )3, wherein x is 0 to 1, y is 0 to 1, and z is 0 to 1. The method for preparing the solution comprises the following steps: Cesium iodide, methylamine bromide, lead bromide, formamidine hydroiodide, and lead iodide powder in a molar ratio of 1:1-5:0.05-5:1-30:1-30 are dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide, wherein the volume ratio of N,N-dimethylformamide and dimethyl sulfoxide is 2-8:1, and stirred at room temperature overnight to obtain the Cs x FA y MA 1-x-y Pb(I z Br 1-z )3 solution.

5. The van der Waals material and polymer synergistically enhanced perovskite solar cell according to claim 3, characterized in that: The Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 The method for preparing the perovskite precursor solution comprises the following steps: Cesium iodide, methylamine bromide, lead bromide, formamidine hydroiodide, and lead iodide powder in a molar ratio of 1:2:3.1:16.2:16.9 are dissolved in a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide, wherein the volume ratio of N,N-dimethylformamide and dimethyl sulfoxide is 2-8:1, and stirred at room temperature overnight to obtain the Cs 0.05 FA 0.81 MA 0.14 PbI 2.55 Br 0.45 of solution.

6. A method for preparing a van der Waals material and polymer synergistically enhanced perovskite solar cell according to any one of claims 1 to 5, characterized in that: The following steps are involved: In the first step, a hole transport layer material solution is spin-coated on the surface of a clean conductive substrate layer, which serves as a hole transport layer; In the second step, the perovskite precursor solution is spin-coated on the hole transport layer prepared above to form a perovskite light absorbing layer film, which is completed in a nitrogen glove box and serves as the perovskite light absorbing layer; The third step is to spin-coat a polymer solution on the surface of the perovskite light-absorbing layer to form a polymer film, which serves as a polymer layer; The fourth step is to cover the van der Waals material on the polymer layer to form a stable van der Waals material polymer double layer structure, which serves as a van der Waals material monolayer; The fifth step is to spin-coat an electron transport layer material solution on the surface of the van der Waals material monolayer, and the layer serves as an electron transport layer; Step 6: Spin-coat a hole blocking layer material solution on the surface of the electron transport layer, and the layer serves as a hole blocking layer; The seventh step is to evaporate metallic silver on the hole blocking layer as a back electrode.

7. The method for preparing a van der Waals material and polymer synergistically enhanced perovskite solar cell according to claim 6, characterized in that: The cleaning steps of the conductive substrate layer are as follows: The conductive substrate was ultrasonically cleaned three times in sequence with deionized water, acetone, and ethanol, and then dried to completely remove the solvent and moisture; The cleaned conductive substrate is dried and treated with ultraviolet ozone for 10 to 30 minutes, and this layer is used as the conductive substrate layer.

8. The method for preparing a van der Waals material and polymer synergistically enhanced perovskite solar cell according to claim 6, characterized in that: The parameters of the first step of spin coating are: 3000 rpm, 30s, heating annealing at a temperature of 80-130°C for 3-20 min; The parameters of the second step spin coating are: 1000 rpm, 5 s, 4000 rpm, 20 s; heating at a temperature of 80~130°C for 5~40 min.

9. The method for preparing a van der Waals material and polymer synergistically enhanced perovskite solar cell according to claim 6, characterized in that: The spin coating parameters in the third step are: 3000 rpm, 30 s; heating at 90-110° C. for 5-15 min; The conditions for forming a stable van der Waals material polymer double-layer structure in the fourth step are: heating at a temperature of 90-110° C. for 3-8 minutes; The spin coating parameters in the fifth step are: 2000 rpm, 45 s.

10. The method for preparing a van der Waals material and polymer synergistically enhanced perovskite solar cell according to claim 6, characterized in that: The spin coating parameters in the sixth step are: 4000 rpm, 45 s; heating at a temperature of 60-90° C. for 5-20 min; In the first step, the preparation method of the hole transport layer material solution is: dissolving the hole transport layer material in anhydrous ethanol to form a hole transport layer material solution with a concentration of 0.1-1 mg / mL; In the third step, the polymer solution is prepared by dissolving the material of the polymer layer in an organic reagent to form a polymer solution with a concentration of 0.05-20 mg / mL.

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