Flexible perovskite solar cell and preparation method thereof

Abstract

This application discloses a flexible perovskite solar cell and its preparation method. The cell structure comprises a flexible substrate and, sequentially laminated on the flexible substrate, a transparent electrode, an electrode modification layer, a block polymer interface layer, a perovskite light-absorbing layer, an electrode buffer layer, and a metal electrode. The perovskite light-absorbing layer comprises perovskite and an azobenzene small molecule additive. As a result, the flexible perovskite solar cell exhibits excellent bending resistance, high photoelectric conversion efficiency, and stability.

Description

Technical Field

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

[0002] In recent years, perovskite solar cells (PSCs) have become one of the most disruptive players in the solar cell industry, garnering widespread attention from academia and industry thanks to their exceptional photoelectric conversion efficiencies (PCEs exceeding 25%). Due to their advantages such as low-temperature solution processing, lightweight, and low cost, PSCs are poised to meet the demands of future energy systems for lightweight, low-energy consumption, and stretchability, driving innovation in portable energy systems and near-space vehicle energy systems.

[0003] When preparing perovskite films on flexible substrates, the inevitable brittleness and poor crystallinity will cause more grain boundaries in the film, causing carrier recombination and ion migration, resulting in reduced battery efficiency and environmental stability. Compared with the negligible charge recombination inside the perovskite grains, the non-radiative recombination caused by interface and grain boundary defects is the main obstacle to achieving high efficiency and long-term stability of PSCs. When bent, the perovskite film will first crack at the grain boundaries. This fracture is difficult to self-repair, resulting in poor bending stability of the battery. How to prepare high-quality, bend-resistant perovskite films on flexible substrates is a key issue that needs to be solved urgently. Summary of the Invention

[0004] The present invention aims to solve, at least to some extent, one of the technical problems in the related art. To this end, one object of the present invention is to provide a flexible perovskite solar cell and a method for preparing the same, wherein the flexible perovskite solar cell has good bending resistance, high photoelectric conversion efficiency, and stability.

[0005] In one aspect, the present invention provides a flexible perovskite solar cell. According to an embodiment of the present invention, the cell structure includes a flexible substrate and a transparent electrode, an electrode modification layer, a block polymer interface layer, a perovskite light-absorbing layer, an electrode buffer layer, and a metal electrode, sequentially stacked on the flexible substrate. The perovskite light-absorbing layer includes perovskite and an azobenzene small molecule additive.

[0006] According to the flexible perovskite solar cell of the embodiment of the present invention, by introducing azobenzene small molecule additives in the perovskite light-absorbing layer, the azobenzene small molecule additives have amino, carboxyl, hydroxyl or sulfonic acid groups, the ions in the perovskite act together on these functional groups, inhibiting ion migration, regulating the perovskite crystallization nucleation and grain growth process. At the same time, due to the strong structure of the benzene ring and high cohesive energy, azobenzene small molecules easily form hydrophobic passivation, thereby improving the photoelectric conversion efficiency and stability of the battery. In addition, by introducing a block polymer interface layer before the perovskite light-absorbing layer, the block copolymer has an interface layer deformation resistance and fatigue resistance, and the perovskite can be partially infiltrated into the perovskite light-absorbing layer during film formation. The elastic insulating polymer enriched at the grain boundary effectively plays a role of stress buffering, thereby improving the bending resistance of the flexible perovskite battery. In summary, the flexible perovskite solar cell of the present application has good bending resistance and high photoelectric conversion efficiency and stability.

[0007] In addition, the flexible perovskite solar cell according to the above embodiment of the present invention may also have the following additional technical features:

[0008] In some embodiments of the present invention, the raw materials of the block polymer interface layer include tert-butyl acrylate monomer, aliphatic polyurethane diacrylate monomer, and an initiator. As a result, hydrogen bonding interactions between the block polymer groups give the interface layer good deformation resistance and fatigue resistance.

[0009] In some embodiments of the present invention, the mass of the aliphatic polyurethane diacrylate monomer accounts for 5-20% of the total mass of the tert-butyl acrylate monomer and the aliphatic polyurethane diacrylate monomer. Thus, the flexible perovskite solar cell has good bending resistance.

[0010] In some embodiments of the present invention, the initiator is a polyolefin thermoplastic elastomer, and the mass of the initiator accounts for 0.2-0.3% of the total mass of the tert-butyl acrylate monomer and the aliphatic polyurethane diacrylate monomer. Thus, the flexible perovskite solar cell has good bending resistance.

[0011] In some embodiments of the present invention, the thickness of the block polymer interface layer is 1 to 10 nm. Thus, the flexible perovskite solar cell has good bending resistance.

[0012] In some embodiments of the present invention, the mass ratio of the perovskite to the azobenzene small molecule additive in the perovskite light-absorbing layer is (35-60): (0.1-0.5). As a result, the flexible perovskite solar cell has high photoelectric conversion efficiency and stability.

[0013] In some embodiments of the present invention, the azobenzene small molecule additive includes at least one of 4,4'-dicarboxylazobenzene, 4,4'-diaminoazobenzene, 4-aminoazobenzene-3-disulfonic acid, 2-amino-5 (3-sulfonic acid azophenyl) azobenzene, 4-dimethylaminophenylazobenzenesulfonyl chloride, 2,4-diamino-3'-trifluoromethylazobenzene, 4,4'-azobenzenedicarboxylate ethyl ester, 4-aminophenylazobenzene-2-sulfonic acid, 4-hydroxy-4'-carboxylazobenzene, p-aminoazobenzene-4-sulfonic acid, and 2,4,3'-triaminoazobenzene. Thus, the flexible perovskite solar cell has high photoelectric conversion efficiency and stability.

[0014] In some embodiments of the present invention, the general chemical formula of the perovskite is ABX m Y 3-m , wherein A includes at least one of Cs, H, NH4, CH3NH3, CH3CH2NH3, CH3(CH2)2NH3, CH3(CH2)3NH3 and NH2=CHNH2; B includes at least one of Pb, Sn and Ge; X and Y independently include at least one of Cl, Br, I, BF4, SCN and PF6; m=0~3.

[0015] In some embodiments of the present invention, the thickness of the perovskite light-absorbing layer is 100 to 1000 nm. Thus, the flexible perovskite solar cell has high photoelectric conversion efficiency and stability.

[0016] In some embodiments of the present invention, the electrode modification layer is an electron transport layer, the electrode buffer layer is a hole transport layer, and the electron transport layer includes TiO2, SnO2, ZnO, PC 61 BM, PC 71 BM, TIPD, ICBA and C 60 -bis, the hole transport layer is formed of organic materials and / or inorganic materials, wherein the organic material includes at least one of Spiro-OMeTAD, P3HT, PCPDTBT, PEDOT:PSS, NPB and TPD, and the inorganic material includes CuI, CuSCN, NiO X , V2O5 and MoO3.

[0017] In some embodiments of the present invention, the electrode modification layer is a hole transport layer, the electrode buffer layer is an electron transport layer, and the hole transport layer includes PTAA, PEDOT:PSS, CuI, CuSCN, NiO X , V2O5 and MoO3, the electron transport layer includes TiO2, SnO2, ZnO, PC 61 BM, PC71 BM, TIPD, ICBA and C 60 -At least one of bis.

[0018] In some embodiments of the present invention, the thickness of the electrode modification layer is 5 to 150 nm.

[0019] In some embodiments of the present invention, the thickness of the electrode buffer layer is 5 to 300 nm.

[0020] In a second aspect of the present invention, a method for preparing the above-mentioned flexible perovskite solar cell is provided. According to an embodiment of the present invention, the method comprises:

[0021] (1) forming a transparent electrode and an electrode modification layer in sequence on a flexible substrate;

[0022] (2) mixing tert-butyl acrylate, aliphatic polyurethane diacrylate, and an initiator and applying the mixture to the surface of the electrode modification layer, and then photocuring the mixture to form a block polymer interface layer on the surface of the electrode modification layer;

[0023] (3) mixing a perovskite precursor material, an azobenzene small molecule additive, and an organic solvent to obtain a mixed solution containing perovskite and the azobenzene small molecule additive;

[0024] (4) coating the mixed solution on the surface of the block polymer interface layer and performing an annealing treatment to form a perovskite light absorbing layer on the surface of the block polymer interface layer;

[0025] (5) An electrode buffer layer and a metal electrode are sequentially formed on the surface of the perovskite light absorbing layer to obtain a flexible perovskite solar cell.

[0026] According to an embodiment of the present invention, a method for preparing the above-mentioned flexible perovskite solar cell is provided, which comprises first forming a transparent electrode and an electrode modification layer in sequence on a flexible substrate; then coating a mixture of tert-butyl acrylate, aliphatic polyurethane diacrylate and an initiator on the surface of the electrode modification layer and performing photocuring to form a block polymer interface layer on the surface of the electrode modification layer; then mixing a perovskite precursor material, an azobenzene small molecule additive and an organic solvent, and reacting the perovskite precursor material to generate perovskite, thereby obtaining a mixed solution containing perovskite and the azobenzene small molecule additive; then coating the mixed solution on the surface of the block polymer interface layer and performing annealing treatment to form a perovskite light-absorbing layer on the surface of the block polymer interface layer. By forming a film through annealing treatment, a large-area, high-quality perovskite film can be obtained without the need for additional film-forming auxiliary means such as vacuuming, air knives and anti-solvents, and the process is simple and easy to implement; finally, an electrode buffer layer and a metal electrode are formed in sequence on the surface of the perovskite light-absorbing layer to obtain a flexible perovskite solar cell. The method of the present application is to introduce azobenzene small molecule additives into the perovskite light-absorbing layer. The azobenzene small molecule additives have amino, carboxyl, hydroxyl or sulfonic acid groups. The ions in the perovskite act together on these functional groups, inhibiting ion migration and regulating the perovskite crystallization nucleation and grain growth process. At the same time, due to the strong benzene ring structure and high cohesive energy, azobenzene small molecules easily form hydrophobic passivation, thereby improving the photoelectric conversion efficiency and stability of the battery. In addition, by introducing a block polymer interface layer before the perovskite light-absorbing layer, the block copolymer has an interface layer deformation resistance and fatigue resistance. When the perovskite is formed into a film, it can be partially infiltrated into the perovskite light-absorbing layer. The elastic insulating polymer enriched at the grain boundary effectively plays a role of stress buffering, thereby improving the bending resistance of the flexible perovskite battery. In summary, the method of the present application can be used to prepare a flexible perovskite solar cell with good bending resistance and high photoelectric conversion efficiency and stability, and the preparation process is relatively simple.

[0027] In addition, the method for preparing the flexible perovskite solar cell according to the above embodiment of the present invention may also have the following additional technical features:

[0028] In some embodiments of the present invention, in step (2), the wavelength of ultraviolet light used for photocuring is 300-400 nm, and the irradiation time is 5-20 minutes.

[0029] In some embodiments of the present invention, in step (3), the concentration of perovskite in the mixed solution is 35-60 wt%, and the concentration of the azobenzene small molecule additive is 0.1-0.5 wt%. As a result, the flexible perovskite solar cell has high photoelectric conversion efficiency and stability.

[0030] In some embodiments of the present invention, in step (2), the organic solvent includes at least one of dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, γ-butyrolactone, dimethylacetamide, 2-butoxyethanol, dimercaptoethanol and acetonitrile.

[0031] In some embodiments of the present invention, in step (4), the annealing treatment is performed at a temperature of 100-150°C and for a time of 10-90 minutes. Thus, a large-area, high-quality perovskite film can be obtained without the need for additional film-forming auxiliary means such as vacuuming, air knives, and anti-solvents, and the process is simple and easy to implement.

[0032] In some embodiments of the present invention, before performing step (4), the flexible substrate is preheated to 40-60° C. Thus, initial crystal nuclei can be formed on the substrate surface at the moment the mixed solution containing perovskite and azobenzene small molecule additive contacts the substrate.

[0033] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0035] Figure 1 is a schematic structural diagram of a flexible perovskite solar cell according to an embodiment of the present invention;

[0036] Figure 2 It is a schematic flow chart of a method for preparing a flexible perovskite solar cell according to one embodiment of the present invention. DETAILED DESCRIPTION

[0037] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0038] In the first aspect of the present invention, the present invention provides a flexible perovskite solar cell. According to an embodiment of the present invention, referring to Figure 1 The battery structure includes a flexible substrate 1 and a transparent electrode 2, an electrode modification layer 3, a block polymer interface layer 4, a perovskite light absorption layer 5, an electrode buffer layer 6 and a metal electrode 7 stacked in sequence on the flexible substrate 1, wherein the above-mentioned perovskite light absorption layer 5 includes perovskite and azobenzene small molecule additives.

[0039] The inventors discovered that by introducing azobenzene small molecule additives into the perovskite light-absorbing layer, the azobenzene small molecule additives have amino, carboxyl, hydroxyl, or sulfonic acid groups. The ions in the perovskite act together on these functional groups, inhibiting ion migration and regulating the perovskite crystallization nucleation and grain growth process. At the same time, due to the strong benzene ring structure and high cohesive energy, the azobenzene small molecule easily forms a hydrophobic passivation, thereby improving the photoelectric conversion efficiency and stability of the battery. In addition, by introducing a block polymer interface layer before the perovskite light-absorbing layer, the block copolymer has anti-deformation and fatigue resistance of the interface layer. When the perovskite film is formed, it can partially penetrate into the perovskite light-absorbing layer. The elastic insulating polymer enriched at the grain boundaries effectively acts as a stress buffer, thereby improving the bending resistance of the flexible perovskite battery.

[0040] In some specific embodiments of the present invention, the block polymer interface layer 4 is formed from raw materials including tert-butyl acrylate monomer, aliphatic polyurethane diacrylate monomer, and an initiator. The block polymer interface layer 4 is formed by mixing the tert-butyl acrylate monomer, aliphatic polyurethane diacrylate monomer, and initiator and then subjecting them to photocuring polymerization. As a result, hydrogen bonding interactions between the block polymer groups impart excellent deformation and fatigue resistance to the interface layer. Specifically, the UV light used for photocuring has a wavelength of 300-400 nm and an irradiation time of 5-20 minutes.

[0041] Furthermore, the mass of the aliphatic polyurethane diacrylate monomer accounts for 5-20% of the total mass of the tert-butyl acrylate monomer and the aliphatic polyurethane diacrylate monomer. The inventors have found that if too little aliphatic polyurethane diacrylate monomer is added, it will not increase the elasticity of the polymer; while if too much aliphatic polyurethane diacrylate monomer is added, the viscosity of the polymer precursor solution will be too high, resulting in an excessively thick block polymer interface layer, which will be unable to transport carriers.

[0042] It should be noted that those skilled in the art can select the specific type of the above-mentioned initiator according to actual needs. For example, the initiator can be a polyolefin thermoplastic elastomer. Furthermore, the mass of the above-mentioned initiator accounts for 0.2 to 0.3% of the total mass of the tert-butyl acrylate monomer and the aliphatic polyurethane diacrylate monomer. The inventors have found that if too little initiator is added, sufficient polymerization cannot be achieved; and if too much initiator is added, local polymerization will be aggravated, affecting the film quality. Therefore, the use of the initiator addition amount of the present application can achieve the best polymerization effect of the tert-butyl acrylate monomer and the aliphatic polyurethane diacrylate monomer, and the film quality of the polymer interface layer is high.

[0043] Furthermore, the thickness of the block polymer interface layer is 1 to 10 nm. The inventors have discovered that if the block polymer interface layer is too thin, it will not induce crystallization of the perovskite film; while if the block polymer interface layer is too thick, it will affect carrier transport and thus affect the photoelectric performance of the battery device. Therefore, the polymer interface layer thickness of the present application is conducive to inducing perovskite film crystallization and carrier transport.

[0044] In some specific embodiments of the present invention, the mass ratio of perovskite to azobenzene small molecule additive in the above-mentioned perovskite light-absorbing layer is (35-60): (0.1-0.5). The inventors have found that if the mass ratio is too small, it will affect the quality of the perovskite light-absorbing layer; and if the mass ratio is too large, it will not play a role in inducing perovskite crystallization nucleation or assisting grain size growth. Therefore, using the mass ratio of the present application, the perovskite light-absorbing layer obtained is of better quality, and the flexible perovskite solar cell has higher photoelectric conversion efficiency and stability.

[0045] It should be noted that the specific type of the above-mentioned azobenzene small molecule additive is not particularly limited, and those skilled in the art can choose according to actual needs. For example, the azobenzene small molecule additive is selected from at least one of 4,4'-dicarboxyazobenzene, 4,4'-diaminoazobenzene, 4-aminoazobenzene-3-disulfonic acid, 2-amino-5 (3-sulfonic acid azophenyl) azobenzene, 4-dimethylaminophenylazobenzenesulfonyl chloride, 2,4-diamino-3'-trifluoromethylazobenzene, 4,4'-azobenzene dicarboxylate ethyl ester, 4-aminophenylazobenzene-2-sulfonic acid, 4-hydroxy-4'-carboxyazobenzene, p-aminoazobenzene-4-sulfonic acid and 2,4,3'-triaminoazobenzene.

[0046] Furthermore, the general chemical formula of the perovskite is ABX m Y 3-m A includes at least one of Cs, H, NH4, CH3NH3, CH3CH2NH3, CH3(CH2)2NH3, CH3(CH2)3NH3 and NH2=CHNH2; B includes at least one of Pb, Sn and Ge; X and Y each independently include at least one of Cl, Br, I, BF4, SCN and PF6; and m=0-3.

[0047] Furthermore, the perovskite light-absorbing layer has a thickness of 100 to 1000 nm. The inventors have discovered that if the perovskite light-absorbing layer is too thin, it cannot fully absorb sunlight, resulting in a low device current. However, if the perovskite light-absorbing layer is too thick, film defects increase in the light-absorbing layer, leading to severe carrier recombination in the light-absorbing layer, which in turn reduces device performance. Therefore, using the perovskite light-absorbing layer thickness of this application results in better device performance.

[0048] In some specific embodiments of the present invention, the electrode modification layer is an electron transport layer, and the electrode buffer layer is a hole transport layer. It should be noted that those skilled in the art can select the specific types of the electron transport layer and the hole transport layer according to actual needs. For example, the electron transport layer includes TiO2, SnO2, ZnO, PC 61 BM, PC 71 BM, TIPD, ICBA and C 60 -bis; the hole transport layer is formed of organic material and / or inorganic material, specifically, the hole transport layer is formed of organic material; or the hole transport layer is formed of inorganic material; or the hole transport layer is formed of organic material and inorganic material, that is, the hole transport layer includes a first hole transport layer and a second hole transport layer, one of which is formed of organic material and the other is formed of inorganic material, the organic material includes at least one of Spiro-OMeTAD, P3HT, PCPDTBT, PEDOT:PSS, NPB and TPD, and the inorganic material includes CuI, CuSCN, NiO X , V2O5 and MoO3.

[0049] In some specific embodiments of the present invention, the electrode modification layer is a hole transport layer, and the electrode buffer layer is an electron transport layer. It should be noted that those skilled in the art can select the specific types of the electron transport layer and the hole transport layer according to actual needs. For example, the hole transport layer includes PTAA, PEDOT:PSS, CuI, CuSCN, NiO X , V2O5 and MoO3, the electron transport layer includes TiO2, SnO2, ZnO, PC 61 BM, PC 71 BM, TIPD, ICBA and C 60 -At least one of bis.

[0050] Furthermore, the thickness of the electrode modification layer is 5 to 150 nm, preferably 10 to 50 nm; the thickness of the electrode buffer layer is 5 to 300 nm, preferably 10 to 150 nm. It should be noted that the specific types of the flexible substrate 1, transparent electrode 2, and metal electrode 7 are not particularly limited and can be selected by those skilled in the art based on actual needs. For example, the flexible substrate 1 may include at least one of PET and PEN; the transparent electrode 2 may be ITO; and the metal electrode 7 may include at least one of gold, silver, copper, and aluminum.

[0051] In the second aspect of the present invention, the present invention provides a method for preparing the above-mentioned flexible perovskite solar cell. Figure 2 , the method comprising:

[0052] S100: Sequentially forming a transparent electrode and an electrode modification layer on a flexible substrate

[0053] In this step, a flexible substrate containing a transparent conductive layer is first laser-etched to form an electrode pattern P1. The substrate is then cleaned, dried, and subjected to UV / ozone treatment for 18 to 22 minutes, preferably 20 minutes, to form a transparent electrode on the flexible substrate. Specifically, the cleaning method may be ultrasonic cleaning with detergent, deionized water, anhydrous ethanol, acetone, and isopropyl alcohol for 4 to 6 minutes, preferably 5 minutes, respectively; the drying method may be drying by oven drying or blowing with nitrogen. The precursor solution of the electrode modification layer is then coated on the surface of the transparent electrode, and the substrate is then placed on a hot plate at 140°C to 160°C, preferably 150°C, and dried for 25 to 35 minutes, preferably 30 minutes, to form an electrode modification layer on the surface of the transparent electrode. It should be noted that the specific types and thicknesses of the transparent electrode and electrode modification layer are the same as those described above and will not be repeated here.

[0054] S200: tert-butyl acrylate, aliphatic polyurethane diacrylate and initiator are mixed and coated on the surface of the electrode modification layer, and then light-cured.

[0055] In this step, a block polymer interface layer is formed on the surface of the electrode modification layer by mixing tert-butyl acrylate, aliphatic polyurethane diacrylate, and an initiator, applying the mixture to the surface, and then UV curing. The inventors have discovered that hydrogen bonding interactions between the block polymer groups impart excellent deformation and fatigue resistance to the interface layer. It should be noted that those skilled in the art can select the coating method described above based on practical needs, such as spin coating, spray coating, or blade coating. Specifically, the UV light used for the photocuring process has a wavelength of 300-400 nm, and the irradiation time is 5-20 minutes. The inventors have discovered that if the irradiation time is too short, the monomers will not fully cure; while if the irradiation time is too long, the sample will overheat and deform. Therefore, using the irradiation time specified in this application ensures sufficient monomer curing while preventing overheating and deformation of the sample. It should be noted that the mixing ratio of tert-butyl acrylate, aliphatic polyurethane diacrylate, and initiator, the specific type of initiator, and the thickness of the block polymer interface layer are the same as those described above and will not be further elaborated here.

[0056] S300: Mixing perovskite precursor materials, azobenzene small molecule additives and organic solvents

[0057] In this step, a perovskite precursor material, an azobenzene small molecule additive and an organic solvent are mixed, wherein the perovskite precursor material reacts to generate perovskite, thereby obtaining a mixed solution containing perovskite and an azobenzene small molecule additive. Preferably, the above mixing process is heated and stirred at 55 to 70°C, preferably 60°C for 6 to 12 hours, thereby ensuring that the perovskite precursor material is fully dissolved, and finally obtaining a transparent mixed solution after the reaction. It should be noted that those skilled in the art can select the specific type of the above perovskite precursor material according to actual needs, as long as it can react to generate a general formula of ABX m Y 3-m The specific types of A, B, X, and Y in the general formula and the value range of m are the same as those described above and will not be repeated here.

[0058] Furthermore, the concentration of perovskite in the above-mentioned mixed perovskite solution is 35-60wt%, and the concentration of the azobenzene small molecule additive is 0.1-0.5wt%. The inventors found that if the concentration of perovskite is too low, the thickness of the light-absorbing layer is too low, affecting the short-circuit current of the battery; and if the concentration of perovskite is too high, the film-forming defects of the light-absorbing layer increase significantly, carrier recombination is serious, and device performance is reduced. Therefore, by adopting the perovskite concentration of the present application, the perovskite light-absorbing layer has a suitable thickness and the performance of the device is better. At the same time, if the concentration of the azobenzene small molecule additive is too low, it cannot play a role in inducing perovskite crystallization nucleation or assisting grain size growth; and if the concentration of the azobenzene small molecule additive is too high, it will affect the quality of the perovskite light-absorbing layer.

[0059] It should be noted that those skilled in the art can select the specific type of organic solvent based on actual needs. For example, the organic solvent includes at least one of dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, γ-butyrolactone, dimethylacetamide, 2-butoxyethanol, dimercaptoethanol, and acetonitrile. Furthermore, the specific type of the azobenzene small molecule additive is the same as described above and will not be repeated here.

[0060] S400: coating the mixed solution on the surface of the block polymer interface layer and performing annealing treatment

[0061] In this step, a perovskite light-absorbing layer is formed on the surface of the block polymer interface layer by applying the mixed solution to the surface and performing an annealing treatment. The inventors discovered that by introducing azobenzene small molecule additives into the perovskite light-absorbing layer, the azobenzene small molecule additives have amino, carboxyl, hydroxyl or sulfonic acid groups, and the ions in the perovskite act together on these functional groups, inhibiting ion migration and regulating the perovskite crystallization nucleation and grain growth process. At the same time, due to the strong benzene ring structure and high cohesive energy, the azobenzene small molecules easily form hydrophobic passivation, thereby improving the photoelectric conversion efficiency and stability of the battery. At the same time, when the perovskite film is formed, the block polymer interface layer with good deformation resistance and fatigue resistance can partially penetrate into the perovskite light-absorbing layer. The elastic insulating polymer enriched at the grain boundary effectively plays a stress buffering role, thereby improving the bending resistance of the flexible perovskite battery. In addition, by using annealing treatment to form the film, large-area high-quality perovskite films can be obtained without the need for additional film-forming auxiliary means such as vacuum extraction, air knives and anti-solvents. The process is simple and easy to implement.

[0062] Preferably, the flexible substrate is preheated to 40-60°C before coating the mixed solution. In this way, the initial crystal nuclei can be formed on the surface of the substrate at the moment when the mixed solution containing perovskite and azobenzene small molecule additive contacts the substrate. The inventors found that if the preheating temperature is too low, the initial crystal nuclei cannot be formed; and if the preheating temperature is too high, the crystal nuclei precipitate too quickly, and the growth of the grain size of the light-absorbing layer film is limited. Therefore, the preheating temperature of the present application is conducive to inducing the crystallization of the perovskite film and obtaining larger-sized perovskite film grains. Preferably, the above-mentioned process of forming the perovskite light-absorbing layer is carried out under the protection of an inert gas (such as nitrogen). It should be noted that those skilled in the art can select the above-mentioned coating method according to actual needs, for example, it can be a doctor blade method, a spin coating method, a spray coating method, a slit coating method or an inkjet printing method.

[0063] Furthermore, the annealing treatment is performed at a temperature of 100-150°C for 10-90 minutes. The inventors discovered that if the annealing temperature is too low, the perovskite crystal structure cannot be formed; while if the annealing temperature is too high, it can induce decomposition of the perovskite film. Furthermore, if the annealing time is too short, the solvent will not evaporate sufficiently, and the perovskite crystal structure will not form fully; while if the annealing time is too long, the surface roughness of the perovskite film will be excessive. Therefore, high-temperature annealing can fully evaporate the solvent in the perovskite film, allowing for rapid growth from the initial crystal nuclei, thereby controlling the grain size and morphology of the perovskite film.

[0064] It should be noted that the thickness of the perovskite light-absorbing layer is the same as described above and will not be repeated here.

[0065] S500: Sequentially forming an electrode buffer layer and a metal electrode on the surface of the perovskite light absorption layer

[0066] In this step, the electrode buffer layer precursor is first coated on the surface of the perovskite light-absorbing layer, and laser etching is performed to form P2; then a metal electrode is prepared on the surface of the electrode buffer layer, and laser etching is performed to form P3, thereby obtaining a flexible perovskite solar cell. It should be noted that the above-mentioned coating method and the preparation method of the metal electrode are not particularly limited, and those skilled in the art can select them according to actual needs. For example, the coating method can be spin coating, spray coating, or blade coating; the metal electrode can be prepared by vacuum evaporation. In addition, the specific type and thickness of the electrode buffer layer and the metal electrode are the same as described above and will not be repeated here.

[0067] The inventors discovered that by first forming a transparent electrode and an electrode modification layer on a flexible substrate in sequence; then mixing tert-butyl acrylate, aliphatic polyurethane diacrylate and an initiator, applying the mixture to the surface of the electrode modification layer and performing photocuring, a block polymer interface layer can be formed on the surface of the electrode modification layer; then mixing a perovskite precursor material, an azobenzene small molecule additive and an organic solvent, and the perovskite precursor material reacts to generate perovskite, thereby obtaining a mixed solution containing perovskite and the azobenzene small molecule additive; then applying the mixed solution to the surface of the block polymer interface layer and performing annealing treatment, a perovskite light-absorbing layer can be formed on the surface of the block polymer interface layer. By using annealing treatment to form a film, there is no need to use additional film-forming auxiliary means such as vacuum extraction, air knife and anti-solvent, and a large-area high-quality perovskite film can be obtained. The process is simple and easy to implement; finally, an electrode buffer layer and a metal electrode are formed in sequence on the surface of the perovskite light-absorbing layer to obtain a flexible perovskite solar cell. The method of the present application is to introduce azobenzene small molecule additives into the perovskite light-absorbing layer. The azobenzene small molecule additives have amino, carboxyl, hydroxyl or sulfonic acid groups. The ions in the perovskite act together on these functional groups, inhibiting ion migration and regulating the perovskite crystallization nucleation and grain growth process. At the same time, due to the strong benzene ring structure and high cohesive energy, azobenzene small molecules easily form hydrophobic passivation, thereby improving the photoelectric conversion efficiency and stability of the battery. In addition, by introducing a block polymer interface layer before the perovskite light-absorbing layer, the block copolymer has an interface layer deformation resistance and fatigue resistance. When the perovskite is formed into a film, it can be partially infiltrated into the perovskite light-absorbing layer. The elastic insulating polymer enriched at the grain boundary effectively plays a role of stress buffering, thereby improving the bending resistance of the flexible perovskite battery. In summary, the method of the present application can be used to prepare a flexible perovskite solar cell with good bending resistance and high photoelectric conversion efficiency and stability, and the preparation process is relatively simple.

[0068] The following embodiments of the present invention are described in detail. It should be noted that the following embodiments are illustrative and are intended only to explain the present invention and are not to be construed as limiting the present invention. In addition, unless otherwise expressly stated, all reagents used in the following embodiments are commercially available or can be synthesized according to methods described herein or known methods. Reaction conditions not listed are also readily available to those skilled in the art.

[0069] Example 1

[0070] The first step is to prepare a transparent electrode:

[0071] The electrode pattern P1 was formed by laser etching of PET / ITO, and ultrasonically cleaned in glass cleaning solution, deionized water, anhydrous ethanol, acetone, and isopropanol for 5 minutes respectively, then dried with nitrogen and treated with UV / ozone for 20 minutes.

[0072] The second step is to prepare the electrode modification layer:

[0073] The precursor solution of low-temperature nano-TiO2 particle colloid was coated on the surface of the transparent electrode, and then placed on a hot plate and dried at 150°C for 30 minutes to form an electrode modification layer with a thickness of 45nm.

[0074] The third step is to prepare the polymer interface layer:

[0075] A block copolymer precursor solution was spin-coated onto the electrode modification layer. The precursor solution consisted of tert-butyl acrylate (tBA) and aliphatic urethane diacrylate (AUD) monomers with an initiator. The weight of AUD accounted for 5% of the total weight of AUD and tBA. The photocuring initiator was a polyolefin thermoplastic elastomer (TPO), with the weight of TPO accounting for 0.2% of the total weight of AUD and tBA. The film was cured under 365nm UV light for 5 minutes to a thickness of 1nm.

[0076] The fourth step is to prepare the perovskite light-absorbing layer:

[0077] Perovskite coating solution preparation: using mixed solvent (DMF / DMSO volume ratio = 4 / 1), according to Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08 )3 formula dissolves PbI2, PbBr2, CsI, iodoformamidine and iodomethylamine perovskite precursors, and the perovskite precursors react to form perovskite Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08)3. Adding azobenzene small molecule additive 4,4'-dicarboxyazobenzene, and then heating and stirring at 60°C for 6 hours, the concentration of perovskite in the obtained mixed solution is 45wt% and the concentration of the additive is 0.1wt%.

[0078] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. The flexible substrate was heated to 40°C, and a certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds. It was then heated and annealed at 150°C for 15 minutes to form a 300nm thick perovskite light-absorbing layer.

[0079] Step 5: Prepare the electrode buffer layer:

[0080] Under nitrogen protection, a hole transport layer was prepared on the perovskite light-absorbing layer by spin coating. 90 mg of Spiro-OMeTAD, 27.5 ml of t-BP, and 17.5 ml of Li-TFSI were added to 1 ml of chlorobenzene, dissolved into a solution, and spin-coated on the surface of the perovskite light-absorbing layer at a speed of 3000 rpm for 30 seconds to obtain an electrode buffer layer with a thickness of 120 nm.

[0081] P2 is formed by laser scribing at a wavelength of 532 nm.

[0082] Step 6: Prepare metal electrodes:

[0083] Gold electrodes were prepared on the surface of the electrode buffer layer by thermal evaporation. -4 The metal electrode is formed by vacuum evaporation of 80nm thick gold film under a vacuum degree of Pa. P3 is formed by laser scribing with a wavelength of 532nm.

[0084] The device structure of the large-area flexible perovskite thin film solar cell prepared by the above method is as follows Figure 1 Shown: PET / ITO / TiO2 / block polymer interface layer / perovskite absorber layer / Spiro-OMeTAD / Au, active area 25cm 2 , the photoelectric conversion efficiency data is shown in Table 1, test conditions: spectral distribution AM1.5G, light intensity 1000W / m 2 The AAA solar simulator (XES-502S+ELS155 from SAN-EI, Japan) was used, and IV curves were measured using a Keithly 2400 digital source meter. All tests were conducted in an ambient environment (25°C, 45% RH). The cell's flex resistance was tested using a flex tester (Hunan Nasheng FlexTest-TM-L) with a bending radius of 2.5mm.

[0085] Example 2

[0086] The third step is to prepare the polymer interface layer:

[0087] A block copolymer precursor solution was spin-coated onto the electrode modification layer. The precursor solution consisted of tert-butyl acrylate (tBA) and aliphatic urethane diacrylate (AUD) monomers with an initiator. The weight of AUD accounted for 15% of the total weight of AUD and tBA. The photocuring initiator was a polyolefin thermoplastic elastomer (TPO), which accounted for 0.2% of the total weight of AUD and tBA. The solution was cured under UV light at 365 nm for 7 minutes, achieving a thickness of 5 nm.

[0088] The fourth step is to prepare the perovskite light-absorbing layer:

[0089] Perovskite coating solution preparation: using mixed solvent (DMF / DMSO volume ratio = 4 / 1), according to Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08 )3 formula dissolves PbI2, PbBr2, CsI, iodoformamidine and iodomethylamine perovskite precursors, and the perovskite precursors react to form perovskite Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08 )3. Add the azobenzene small molecule additive 4-aminoazobenzene-3-disulfonic acid, and then heat and stir at 60°C for 8 hours. The concentration of perovskite in the obtained mixed solution is 45wt%, and the concentration of the additive is 0.3wt%.

[0090] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. The flexible substrate was heated to 40°C, and a certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds. It was then heated and annealed at 130°C for 30 minutes to form a 400nm thick perovskite light-absorbing layer.

[0091] The preparation methods of other steps are the same as those in Example 1.

[0092] The device structure of the organic-inorganic hybrid perovskite thin film solar cell prepared by the above method is as follows Figure 1 Shown: PET / ITO / TiO2 / block polymer interface layer / perovskite absorber layer / Spiro-OMeTAD / Au, active area 25cm 2 The photoelectric conversion efficiency data are shown in Table 1, and the test conditions are the same as those in Example 1.

[0093] Example 3

[0094] The third step is to prepare the polymer interface layer:

[0095] A block copolymer precursor solution was spin-coated onto the electrode modification layer. The precursor solution consisted of tert-butyl acrylate (tBA) and aliphatic urethane diacrylate (AUD) monomers with an initiator. The weight of AUD accounted for 20% of the total weight of AUD and tBA. The photocuring initiator was a polyolefin thermoplastic elastomer (TPO), with the weight of TPO accounting for 0.2% of the total weight of AUD and tBA. The film was cured under 365nm UV light for 7 minutes to a thickness of 5nm.

[0096] The fourth step is to prepare the perovskite light-absorbing layer:

[0097] Perovskite coating solution preparation: using mixed solvent (DMF / DMSO volume ratio = 4 / 1), according to Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08 )3 formula dissolves PbI2, PbBr2, CsI, iodoformamidine and iodomethylamine perovskite precursors, and the perovskite precursors react to form perovskite Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08 )3. Add the azobenzene small molecule additive 4-aminoazobenzene-3-disulfonic acid, and then heat and stir at 60°C for 8 hours to obtain a mixed solution with a perovskite concentration of 35wt% and an additive concentration of 0.3wt%.

[0098] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. The flexible substrate was heated to 40°C, and a certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds. It was then heated and annealed at 130°C for 30 minutes to form a 400nm thick perovskite light-absorbing layer.

[0099] The preparation methods of other steps are the same as those in Example 1.

[0100] The device structure of the organic-inorganic hybrid perovskite thin film solar cell prepared by the above method is as follows Figure 1 Shown: PET / ITO / TiO2 / block polymer interface layer / perovskite absorber layer / Spiro-OMeTAD / Au, active area 25cm 2 The photoelectric conversion efficiency data are shown in Table 1, and the test conditions are the same as those in Example 1.

[0101] Example 4

[0102] The first step is to prepare a transparent electrode:

[0103] The PEN / ITO was laser etched to form an electrode pattern P1, which was then ultrasonically cleaned in glass cleaning solution, deionized water, anhydrous ethanol, acetone, and isopropanol for 5 minutes respectively, then dried with nitrogen and treated with UV / ozone for 30 minutes.

[0104] The second step is to prepare the electrode modification layer:

[0105] Weigh 5nm NiO particles x The powder was dissolved in deionized water and ultrasonically dispersed to a concentration of 30 mg / ml. The powder was spin-coated on the surface of the transparent electrode at a spin coater speed of 1000 rpm for 30 seconds, and then dried at 100°C for 5 minutes to form a film with a thickness of 30 nm.

[0106] The third step is to prepare the polymer interface layer:

[0107] A block copolymer precursor solution composed of tert-butyl acrylate (tBA) and aliphatic urethane diacrylate (AUD) monomers and an initiator was spin-coated on the electrode modification layer. The AUD content was 10% of the total weight of AUD and tBA. The photocuring initiator was a polyolefin thermoplastic elastomer (TPO), which accounted for 0.2% of the total weight of AUD and tBA. The solution was cured under 365nm UV light for 20 minutes to a thickness of 5nm.

[0108] The fourth step is to prepare the perovskite light-absorbing layer:

[0109] Preparation of perovskite coating liquid: PbI2, PbCl2, CH3NH3I, and 4-dimethylaminophenylazobenzenesulfonyl chloride are dissolved together in a 2-ME / CAN (volume ratio = 2 / 1) mixed solvent according to a certain mass ratio (the molar ratio of PbI2, PbCl2, and CH3NH3I is 1:1:4). Then, after heating and stirring at 60°C for 6 hours, the concentration of perovskite in the obtained mixed solution is 45wt%, and the concentration of additives is 0.5wt%.

[0110] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. The flexible substrate was heated to 60°C, and a certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds. It was then heated and annealed at 100°C for 45 minutes to form a 550nm thick CH3NH3PbI x Cl 3-x (x=0~3) perovskite light-absorbing layer.

[0111] Step 5: Prepare the electrode buffer layer:

[0112] A 20 mg / ml PCBM chlorobenzene solution was spin-coated on the surface of the perovskite light-absorbing layer at a speed of 1000 rpm for 40 seconds and dried at 70°C for 10 minutes to form an electrode buffer layer with a thickness of 40 nm.

[0113] P2 is formed by laser scribing at a wavelength of 532 nm.

[0114] Step 6: Prepare metal electrodes:

[0115] In 5×10 -4 Under a vacuum degree of Pa, a 120nm thick aluminum film is vacuum-deposited on the surface of the electrode buffer layer to form a metal electrode. P3 is formed by laser scribing with a wavelength of 532nm.

[0116] The device structure of the large-area flexible perovskite thin film solar cell prepared by the above method is as follows Figure 1 Shown: PEN / ITO / NiO x / block polymer interface layer / CH3NH3PbI x Cl 3-x / PCBM / Al, effective area 25cm 2 , the photoelectric conversion efficiency data is shown in Table 2, test conditions: spectral distribution AM1.5G, light intensity 1000W / m 2 , AAA solar simulator (XES-502S+ELS155 from SAN-EI, Japan), and the IV curve were measured using a Keithly2400 digital source meter. All tests were carried out in an atmospheric environment (25°C, 45RH%).

[0117] Example 5

[0118] The third step is to prepare the polymer interface layer:

[0119] A block copolymer precursor solution was spin-coated onto the electrode modification layer. The precursor solution consisted of tert-butyl acrylate (tBA) and aliphatic urethane diacrylate (AUD) monomers with an initiator. The weight of AUD accounted for 20% of the total weight of AUD and tBA. The photocuring initiator was a polyolefin thermoplastic elastomer (TPO), with the weight of TPO accounting for 0.2% of the total weight of AUD and tBA. The film was cured under 365nm UV light for 15 minutes to a thickness of 6nm.

[0120] The fourth step is to prepare the perovskite light-absorbing layer:

[0121] Preparation of perovskite coating liquid: PbI2, PbCl2, CH3NH3I, and ethyl 4,4'-azobenzenedicarboxylate are dissolved together in a 2-ME / CAN (volume ratio = 2 / 1) mixed solvent according to a certain mass ratio (the molar ratio of PbI2, PbCl2, and CH3NH3I is 1:1:4). Then, after heating and stirring at 70°C for 12 hours, the concentration of perovskite in the obtained mixed solution is 60wt%, and the concentration of additives is 0.2wt%.

[0122] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. The flexible substrate was heated to 60°C, and a certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds. It was then heated and annealed at 100°C for 45 minutes to form a 550nm thick CH3NH3PbI x Cl 3-x (x=0~3) perovskite light-absorbing layer.

[0123] The preparation methods of other steps are the same as those in Example 4.

[0124] The device structure of the large-area flexible perovskite solar cell prepared by the above method is as follows Figure 1 PEN / ITO / NiO shown x / block polymer interface layer / CH3NH3PbI x Cl 3-x / PCBM / Al, effective area 25cm 2 The photoelectric conversion efficiency data are shown in Table 2, and the test conditions are the same as those in Example 4.

[0125] Example 6

[0126] The third step is to prepare the polymer interface layer:

[0127] A block copolymer precursor solution was spin-coated onto the electrode modification layer. The precursor solution consisted of tert-butyl acrylate (tBA) and aliphatic urethane diacrylate (AUD) monomers with an initiator. The weight of AUD accounted for 10% of the total weight of AUD and tBA. The photocuring initiator was a polyolefin thermoplastic elastomer (TPO), with the weight of TPO accounting for 0.2% of the total weight of AUD and tBA. The film was cured under 365nm UV light for 20 minutes to a thickness of 8nm.

[0128] The fourth step is to prepare the perovskite light-absorbing layer:

[0129] Preparation of perovskite coating liquid: PbI2, PbCl2, CH3NH3I, and 4-dimethylaminophenylazobenzenesulfonyl chloride are dissolved together in a 2-ME / CAN (volume ratio = 2 / 1) mixed solvent according to a certain mass ratio (the molar ratio of PbI2, PbCl2, and CH3NH3I is 1:1:4). Then, after heating and stirring at 70°C for 8 hours, the concentration of perovskite in the obtained mixed solution is 35wt%, and the concentration of additives is 0.1wt%.

[0130] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. The flexible substrate was heated to 60°C, and a certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds. It was then heated and annealed at 100°C for 45 minutes to form a 350nm thick CH3NH3PbI x Cl 3-x (x=0~3) perovskite light-absorbing layer.

[0131] The preparation methods of other steps are the same as those in Example 4.

[0132] The device structure of the large-area flexible perovskite solar cell prepared by the above method is as follows Figure 1 PEN / ITO / NiO shown x / block polymer interface layer / CH3NH3PbI x Cl 3-x / PCBM / Al, effective area 25cm 2 The photoelectric conversion efficiency data are shown in Table 2, and the test conditions are the same as those in Example 4.

[0133] Comparative Example 1

[0134] No block polymer interface layer was prepared.

[0135] The fourth step is to prepare the perovskite light-absorbing layer:

[0136] Perovskite coating solution preparation: using mixed solvent (DMF / DMSO volume ratio = 4 / 1), according to Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08 )3 formula dissolves PbI2, PbBr2, CsI, iodoformamidine and iodomethylamine perovskite precursors to react and generate perovskite Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08)3. Adding azobenzene small molecule additive 4,4'-dicarboxyazobenzene, and then heating and stirring at 60°C for 6 hours, the concentration of perovskite in the obtained mixed solution is 35wt% and the concentration of the additive is 0.1wt%.

[0137] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. The flexible substrate was heated to 40°C, and a certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds. It was then heated and annealed at 150°C for 15 minutes to form a 350nm thick perovskite light-absorbing layer.

[0138] The preparation methods of other steps are the same as those in Example 1.

[0139] The device structure of the large-area flexible perovskite thin film solar cell prepared by the above method is as follows Figure 1 Shown: PET / ITO / TiO2 / block polymer interface layer / perovskite absorber layer / spiro-OMeTAD / Au, active area 25cm 2 The photoelectric conversion efficiency data are shown in Table 1, and the test conditions are the same as those in Example 1.

[0140] Comparative Example 2 does not add azobenzene small molecule additive

[0141] The fourth step is to prepare the perovskite light-absorbing layer:

[0142] Perovskite coating solution preparation: using mixed solvent (DMF / DMSO volume ratio = 4 / 1), according to Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08 )3 formula dissolves PbI2, PbBr2, CsI, iodoformamidine and iodomethylamine perovskite precursors to react and generate perovskite Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08 )3, and then heated and stirred at 60°C for 6 hours to obtain a perovskite solution with a perovskite concentration of 45 wt%.

[0143] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. The flexible substrate was heated to 40°C, and a certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds. It was then heated and annealed at 150°C for 15 minutes to form a 300nm thick perovskite light-absorbing layer.

[0144] The preparation methods of other steps are the same as those in Example 1.

[0145] The device structure of the organic-inorganic hybrid perovskite thin film solar cell prepared by the above method is as follows Figure 1 Shown: PET / ITO / TiO2 / block polymer interface layer / perovskite absorber layer / spiro-OMeTAD / Au, active area 25cm 2 The photoelectric conversion efficiency data are shown in Table 1, and the test conditions are the same as those in Example 1.

[0146] Comparative Example 3: No flexible substrate preheating

[0147] The third step is to prepare the polymer interface layer:

[0148] A block copolymer precursor solution was spin-coated onto the electrode modification layer. The precursor solution consisted of tert-butyl acrylate (tBA) and aliphatic urethane diacrylate (AUD) monomers with an initiator. The weight of AUD accounted for 5% of the total weight of AUD and tBA. The photocuring initiator was a polyolefin thermoplastic elastomer (TPO), with the weight of TPO accounting for 0.2% of the total weight of AUD and tBA. The film was cured under 365nm UV light for 5 minutes to a thickness of 1nm.

[0149] The fourth step is to prepare the perovskite light-absorbing layer:

[0150] Perovskite coating solution preparation: using mixed solvent (DMF / DMSO volume ratio = 4 / 1), according to Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 Pb(I 0.92 Br 0.08 )3 formula dissolves PbI2, PbBr2, CsI, iodoformamidine and iodomethylamine perovskite precursors to react and generate perovskite Cs 0.05 (FA 0.92 MA 0.08 ) 0.95 , adding azobenzene small molecule additive 4,4'-dicarboxyazobenzene, and then heating and stirring at 60°C for 6 hours, the concentration of perovskite in the obtained mixed solution is 45wt% and the concentration of the additive is 0.1wt%.

[0151] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. A certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds, and then heated and annealed at 150°C for 15 minutes to form a 400 nm thick perovskite light-absorbing layer.

[0152] The preparation methods of other steps are the same as those in Example 1.

[0153] The device structure of the organic-inorganic hybrid perovskite thin film solar cell prepared by the above method is as follows Figure 1 Shown: PET / ITO / TiO2 / block polymer interface layer / perovskite absorber layer / spiro-OMeTAD / Au, active area 25cm 2 The photoelectric conversion efficiency data are shown in Table 1, and the test conditions are the same as those in Example 1.

[0154] Comparative Example 4

[0155] No block polymer interface layer was prepared.

[0156] The fourth step is to prepare the perovskite light-absorbing layer:

[0157] Preparation of perovskite coating liquid: PbI2, PbCl2, CH3NH3I, and 4-dimethylaminophenylazobenzenesulfonyl chloride are dissolved together in a 2-ME / CAN (volume ratio = 2 / 1) mixed solvent according to a certain mass ratio (the molar ratio of PbI2, PbCl2, and CH3NH3I is 1:1:4). Then, after heating and stirring at 70°C for 6 hours, the concentration of perovskite in the obtained mixed solution is 55wt%, and the concentration of additives is 0.5wt%.

[0158] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. The flexible substrate was heated to 60°C, and a certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds. It was then heated and annealed at 100°C for 45 minutes to form a 550nm thick CH3NH3PbI x Cl 3-x (x=0~3) perovskite light-absorbing layer.

[0159] The preparation methods of other steps are the same as those in Example 4.

[0160] The device structure of a large-area flexible solar cell prepared by the above method is as follows Figure 1 Shown: PEN / ITO / NiO x / block polymer interface layer / CH3NH3PbI x Cl 3-x / PCBM / Al, effective area 25cm 2 The photoelectric conversion efficiency data are shown in Table 2, and the test conditions are the same as those in Example 4.

[0161] Comparative Example 5 does not add azobenzene small molecule additive

[0162] The third step is to prepare the polymer interface layer:

[0163] A block copolymer precursor solution composed of tert-butyl acrylate (tBA) and aliphatic urethane diacrylate (AUD) monomers and an initiator was spin-coated on the electrode modification layer. The AUD content was 10% of the total weight of AUD and tBA. The photocuring initiator was a polyolefin thermoplastic elastomer (TPO), which accounted for 0.2% of the total weight of AUD and tBA. The solution was cured under 365nm UV light for 20 minutes to a thickness of 5nm.

[0164] The fourth step is to prepare the perovskite light-absorbing layer:

[0165] Preparation of perovskite coating liquid: PbI2, PbCl2, and CH3NH3I are dissolved together in a 2-ME / CAN (volume ratio = 2 / 1) mixed solvent in a certain mass ratio (the molar ratio of PbI2, PbCl2, and CH3NH3I is 1:1:4). Then, after heating and stirring at 70°C for 6 hours, the concentration of perovskite in the obtained mixed solution is 45wt%, and the concentration of additives is 0.3wt%.

[0166] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. The flexible substrate was heated to 60°C, and a certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds. It was then heated and annealed at 100°C for 45 minutes to form a 550nm thick CH3NH3PbI x Cl 3-x (x=0~3) perovskite light-absorbing layer.

[0167] The preparation methods of other steps are the same as those in Example 4.

[0168] The device structure of a large-area flexible solar cell prepared by the above method is as follows Figure 1 Shown: PEN / ITO / NiO x / block polymer interface layer / CH3NH3PbI x Cl 3-x / PCBM / Al, effective area 25cm 2 The photoelectric conversion efficiency data are shown in Table 2, and the test conditions are the same as those in Example 4.

[0169] Comparative Example 6: No flexible substrate preheating

[0170] The third step is to prepare the polymer interface layer:

[0171] A block copolymer precursor solution composed of tert-butyl acrylate (tBA) and aliphatic urethane diacrylate (AUD) monomers and an initiator was spin-coated on the electrode modification layer. The AUD content was 10% of the total weight of AUD and tBA. The photocuring initiator was a polyolefin thermoplastic elastomer (TPO), which accounted for 0.2% of the total weight of AUD and tBA. The solution was cured under 365nm UV light for 20 minutes to a thickness of 5nm.

[0172] The fourth step is to prepare the perovskite light-absorbing layer:

[0173] Preparation of perovskite coating liquid: PbI2, PbCl2, CH3NH3I, and 4-dimethylaminophenylazobenzenesulfonyl chloride are dissolved together in a 2-ME / CAN (volume ratio = 2 / 1) mixed solvent according to a certain mass ratio (the molar ratio of PbI2, PbCl2, and CH3NH3I is 1:1:4). Then, after heating and stirring at 60°C for 8 hours, the concentration of perovskite in the obtained mixed solution is 45wt%, and the concentration of additives is 0.5wt%.

[0174] Preparation of perovskite light-absorbing layer: The perovskite light-absorbing layer was prepared by a one-step solution method under nitrogen protection. A certain volume of perovskite solution was spin-coated on the surface of the polymer interface layer at a speed of 5000 rpm for 30 seconds, and then heated and annealed at 100°C for 45 minutes to form a 550 nm thick CH3NH3PbI x Cl 3-x (x=0~3) perovskite light-absorbing layer.

[0175] The preparation methods of other steps are the same as those in Example 4.

[0176] The device structure of the organic-inorganic hybrid perovskite-based solar cell prepared by the above method is as follows: Figure 1 Shown: PEN / ITO / NiO x / block polymer interface layer / CH3NH3PbI x Cl 3-x / PCBM / Al, effective area 25cm 2 The photoelectric conversion efficiency data are shown in Table 2, and the test conditions are the same as those in Example 4.

[0177] Table 1: Performance characteristics of batteries prepared in Examples 1 to 3 and Comparative Examples 1 to 3

[0178]

[0179] Table 2: Performance characteristics of batteries prepared in Examples 4 to 6 and Comparative Examples 4 to 6

[0180]

[0181]

[0182] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0183] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A flexible perovskite solar cell, characterized in that: The battery structure includes a flexible substrate and a transparent electrode, an electrode modification layer, a block polymer interface layer, a perovskite light absorption layer, an electrode buffer layer and a metal electrode stacked in sequence on the flexible substrate, wherein the perovskite light absorption layer includes perovskite and azobenzene small molecule additives. The raw materials of the block polymer interface layer include tert-butyl acrylate monomer, aliphatic polyurethane diacrylate monomer and initiator; The azobenzene small molecule additive includes at least one of 4,4'-dicarboxylazobenzene, 4,4'-diaminoazobenzene, 4-aminoazobenzene-3-disulfonic acid, 2-amino-5 (3-sulfonic acid azophenyl) azobenzene, 4-dimethylaminophenylazobenzenesulfonyl chloride, 2,4-diamino-3'-trifluoromethylazobenzene, 4,4'-azobenzenedicarboxylate ethyl ester, 4-aminophenylazobenzene-2-sulfonic acid, 4-hydroxy-4'-carboxylazobenzene, p-aminoazobenzene-4-sulfonic acid and 2,4,3'-triaminoazobenzene; During the preparation of the flexible perovskite solar cell, the flexible substrate is preheated to 40-60° C. before the perovskite mixed solution is coated on the surface of the block polymer interface layer, wherein the perovskite mixed solution includes the perovskite, the azobenzene small molecule additive and an organic solvent.

2. The flexible perovskite solar cell according to claim 1, characterized in that The mass of the aliphatic polyurethane diacrylate monomer accounts for 5 to 20% of the total mass of the tert-butyl acrylate monomer and the aliphatic polyurethane diacrylate monomer.

3. The flexible perovskite solar cell according to claim 1, characterized in that The initiator is a polyolefin thermoplastic elastomer, and the mass of the initiator accounts for 0.2-0.3% of the total mass of the tert-butyl acrylate monomer and the aliphatic polyurethane diacrylate monomer.

4. The flexible perovskite solar cell according to claim 1, characterized in that The thickness of the block polymer interface layer is 1 to 10 nm.

5. The flexible perovskite solar cell according to claim 1, characterized in that In the perovskite light-absorbing layer, the mass ratio of the perovskite to the azobenzene small molecule additive is (35-60): (0.1-0.5).

6. The flexible perovskite solar cell according to claim 1, characterized in that The general chemical formula of the perovskite is ABX m Y 3-m , wherein A includes at least one of Cs, NH4, CH3NH3, CH3CH2NH3, CH3(CH2)2NH3, CH3(CH2)3NH3 and NH2=CHNH2; B includes at least one of Pb, Sn and Ge; X and Y independently include at least one of Cl, Br, I, BF4, SCN and PF6; m=0~3.

7. The flexible perovskite solar cell according to claim 1, characterized in that The thickness of the perovskite light-absorbing layer is 100 to 1000 nm.

8. The flexible perovskite solar cell according to claim 1, characterized in that The electrode modification layer is an electron transport layer, the electrode buffer layer is a hole transport layer, and the electron transport layer includes TiO2, SnO2, ZnO, PC 61 BM, PC 71 BM, TIPD, ICBA and C 60 -bis, the hole transport layer is formed of organic materials and / or inorganic materials, wherein the organic material includes at least one of Spiro-OMeTAD, P3HT, PCPDTBT, PEDOT:PSS, NPB and TPD, and the inorganic material includes CuI, CuSCN, NiO X , V2O5 and MoO3.

9. The flexible perovskite solar cell according to claim 1, characterized in that: The electrode modification layer is a hole transport layer, the electrode buffer layer is an electron transport layer, and the hole transport layer includes PTAA, PEDOT:PSS, CuI, CuSCN, NiO X , V2O5 and MoO3, the electron transport layer includes TiO2, SnO2, ZnO, PC 61 BM, PC 71 BM, TIPD, ICBA and C 60 -At least one of bis.

10. The flexible perovskite solar cell according to claim 1, characterized in that: The thickness of the electrode modification layer is 5 to 150 nm.

11. The flexible perovskite solar cell according to claim 1, characterized in that: The thickness of the electrode buffer layer is 5 to 300 nm.

12. A method for preparing the flexible perovskite solar cell according to any one of claims 1 to 11, characterized in that: include: (1) forming a transparent electrode and an electrode modification layer in sequence on a flexible substrate; (2) mixing tert-butyl acrylate, aliphatic polyurethane diacrylate, and an initiator and applying the mixture to the surface of the electrode modification layer, and then photocuring the mixture to form a block polymer interface layer on the surface of the electrode modification layer; (3) mixing a perovskite precursor material, an azobenzene small molecule additive, and an organic solvent to obtain a mixed solution containing perovskite and the azobenzene small molecule additive; (4) coating the mixed solution on the surface of the block polymer interface layer and performing an annealing treatment to form a perovskite light absorbing layer on the surface of the block polymer interface layer; (5) forming an electrode buffer layer and a metal electrode in sequence on the surface of the perovskite light absorbing layer to obtain a flexible perovskite solar cell; Before performing step (4), the flexible substrate is preheated to 40-60°C.

13. The method according to claim 12, characterized in that In step (2), the wavelength of ultraviolet light used for photocuring is 300 to 400 nm, and the irradiation time is 5 to 20 minutes.

14. The method according to claim 12, characterized in that In step (3), the concentration of perovskite in the mixed solution is 35-60 wt%, and the concentration of the azobenzene small molecule additive is 0.1-0.5 wt%.

15. The method according to claim 12, characterized in that In step (3), the organic solvent includes at least one of dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, γ-butyrolactone, dimethylacetamide, 2-butoxyethanol, dimercaptoethanol and acetonitrile.

16. The method according to claim 12, characterized in that In step (4), the annealing treatment is performed at a temperature of 100 to 150° C. and for a time of 10 to 90 minutes.

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