Perovskite solar cell and preparation method thereof

Abstract

The invention provides a perovskite solar cell and a preparation method thereof. The perovskite solar cell comprises a substrate, a first transparent conductive layer, a first carrier transport layer, a passivation layer, a perovskite light absorption layer, a second carrier transport layer, a second transparent conductive layer and a metal electrode which are stacked. The first carrier transport layer and the second carrier transport layer are respectively arranged on two opposite sides of the perovskite light absorption layer; the passivation layer is arranged between the perovskite light absorption layer and the first carrier transmission layer, and / or the passivation layer is arranged between the perovskite light absorption layer and the second carrier transmission layer; the material of the passivation layer comprises supramolecular ionic gel, and the supramolecular ionic gel is composed of a polymer and an imidazole halogen ionic compound. The passivation layer provided by the invention has good flexibility and bending performance, so that the film forming quality of the perovskite thin film and the photoelectric conversion efficiency and operation stability of the perovskite solar cell are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solar cell materials, and particularly relates to a perovskite solar cell and a preparation method thereof. BACKGROUND

[0002] In recent years, with the rise of wearable products and self-powered flexible electronic products, the market demand for flexible perovskite solar cells (FPSCs) is increasing, mainly because perovskite thin films can be prepared at low temperature, are light in weight, have flexibility and are compatible with various curved surfaces.

[0003] The biggest feature of the flexible perovskite solar cell is bendability and recoverability. The traditional recoverability refers to the ability of an object to deform under the action of an external force and to recover from the deformation after the external force is removed. The recoverability of the object is related to the characteristics of the material itself. Therefore, in order to obtain a FPSC with high recoverability, the composition and preparation method of the FPSC need to be optimized.

[0004] The FPSC mainly includes a flexible substrate, an electrode, a perovskite light-absorbing material and a charge transport material. The film forming quality of the perovskite light-absorbing material determines the overall quality of the FPSC. Unlike the performance of rigid perovskite solar cells, the FPSC needs to be repeatedly stretched and bent many times, so the FPSC needs to have good elastic ability. However, the perovskite light-absorbing material has a brittle structure due to its polycrystalline structure, and the grain boundaries are easily damaged. In particular, during the bending process, the perovskite light-absorbing layer will produce cracks of different degrees, and these cracks will produce free electron-hole recombination centers. The higher the density of the electron-hole recombination centers, the lower the lifetime of the corresponding carriers, which further reduces the efficiency and operating stability of the device.

[0005] Therefore, there is an urgent need in the art to develop a flexible perovskite solar cell to improve its own bendability and recoverability. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide a perovskite solar cell and a preparation method thereof. The passivation layer provided by the present application has good flexibility and bending performance, thereby improving the film forming quality of the perovskite thin film and the photoelectric conversion efficiency and operating stability of the perovskite solar cell assembled therefrom.

[0007] To achieve the purpose of the present application, the following technical solutions are adopted:

[0008] In a first aspect, the present application provides a perovskite solar cell, which comprises a substrate, a first transparent conductive layer, a first carrier transport layer, a passivation layer, a perovskite light-absorbing layer, a second carrier transport layer, a second transparent conductive layer and a metal electrode arranged in a stack; the first carrier transport layer and the second carrier transport layer are respectively arranged on opposite sides of the perovskite light-absorbing layer; the passivation layer is arranged between the perovskite light-absorbing layer and the first carrier transport layer, and / or the passivation layer is arranged between the perovskite light-absorbing layer and the second carrier transport layer; the material of the passivation layer comprises a supramolecular ionic gel, which is composed of a polymer and an imidazole halide ion compound.

[0009] In one aspect, the present application provides a supramolecular ionic gel for a perovskite solar cell, which constructs a supramolecular ionic network through the synergistic effect of force-induced crystallization and an imidazole halide ion compound; specifically, the hydroxyl group in the polymer structure can form a hydrogen bond with the carbon-hydrogen bond in the imidazole structure, so that it has good flexibility and can provide a solid and flexible substrate for the perovskite light-absorbing layer.

[0010] In another aspect, the present application deposits the supramolecular ionic gel between the perovskite light-absorbing layer and the carrier transport layer; the hydroxyl group in the polymer structure and the carbon-hydrogen bond in the imidazole structure in the supramolecular ionic gel can both form a hydrogen bond with the halide ion in the perovskite material, thereby inhibiting ion migration; in addition, the hydroxyl group in the polymer structure can also form a hydrogen bond with Pb 2+ to form a supramolecular effect, thereby ultimately inhibiting the degradation of the perovskite film; at the same time, the halide anion contained in the supramolecular ionic gel can also well fill the halogen defects, thereby improving the overall quality of the perovskite film.

[0011] Preferably, the polymer comprises polyvinyl alcohol.

[0012] Preferably, the molecular weight of the polymer is 50-300 thousand, preferably 180-230 thousand, for example, it can be 50 thousand, 80 thousand, 100 thousand, 120 thousand, 150 thousand, 180 thousand, 200 thousand, 220 thousand, 230 thousand, 250 thousand, 280 thousand, 300 thousand, etc.

[0013] In the present application, by adjusting the molecular weight of the polymer, the polymer has good strength and flexibility; if the molecular weight is too low, the strength and flexibility of the polymer will be reduced, and vice versa, which will affect the transport of carriers and thus the photoelectric conversion efficiency of the perovskite solar cell.

[0014] Preferably, the imidazole halide ion compound comprises a 1-alkyl-2,3-alkylimidazole halide salt having the structure shown in Formula 1:

[0015]

[0016] wherein R1, R2, R3 are each independently selected from hydrogen, C1-C15 linear alkyl or C2-C15 alkenyl, Y - is selected from any one of Cl - , Br - or I - .

[0017] In the present application, the C1-C15 linear alkyl includes methyl, ethyl, propyl, butyl, hexyl, decyl, hexadecyl, dimethyl, etc.

[0018] In the present application, the C2-C15 alkenyl includes vinyl, propenyl, butenyl, etc.

[0019] Preferably, the imidazole halide ion compound includes any one of 1-ethyl-3-methyl imidazole bromide, 1-butyl-3-methyl imidazole bromide, 1-decyl-3-methyl imidazole bromide, 1-hexadecyl-3-methyl imidazole bromide, 1,2-dimethyl-3-ethyl imidazole bromide, 1-propyl-2,3-dimethyl imidazole bromide, 1-hexyl-2,3-dimethyl imidazole bromide, 1-decyl-2,3-dimethyl imidazole bromide, 1-ethyl-2,3-dimethyl imidazole bromide, 1-ethyl-2,3-dimethyl imidazole chloride, 1-ethyl-2,3-dimethyl imidazole iodide, 1-dodecyl-2,3-dimethyl imidazole bromide, 1,3-didecyl-2-methyl imidazoline chloride, 1-vinyl-3-butyl imidazole bromide, 1-vinyl-3-ethyl imidazole bromide, 1-allyl-3-vinyl imidazole bromide, 1-allyl-2,3-dimethyl imidazole bromide, 1-allyl-2,3-dimethyl imidazole iodide or 1-vinyl-3-ethyl imidazole iodide or a combination of at least two thereof.

[0020] Preferably, the mass ratio of the polymer and the imidazole halide ion compound is (0.2-1.5):1, preferably (0.8-1.2):1, for example, can be 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, etc.

[0021] In the present application, by adjusting the mass ratio of the polymer and the imidazole halide ion compound, the prepared supramolecular ionic gel has good flexibility and the effect of passivating the defects of the perovskite film, and too low mass ratio will reduce the flexibility of the supramolecular ionic gel, thereby affecting the flexible performance of the perovskite solar cell, and at the same time, it cannot well passivate the defects of the perovskite film, affecting the battery efficiency; on the contrary, it will hinder the transport of carriers, resulting in a decrease in the efficiency of the battery.

[0022] Preferably, the thickness of the passivation layer is 2-5 nm, for example, it can be 2 nm, 3 nm, 4 nm, 5 nm, etc.

[0023] Preferably, the thickness of the perovskite light-absorbing layer is 300-700 nm, for example, it can be 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, etc.

[0024] Preferably, the perovskite light-absorbing layer comprises divalent metal cation lead.

[0025] Preferably, the substrate comprises a flexible substrate material.

[0026] Preferably, the flexible substrate material includes at least one selected from polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or colorless polyimide (CPI).

[0027] In a second aspect, the present invention provides a method for preparing a perovskite solar cell according to the first aspect, the method comprising the following steps:

[0028] A first transparent conductive layer is formed on the substrate surface;

[0029] A first carrier transport layer is formed on the surface of the first transparent conductive layer;

[0030] An aqueous solution containing the polymer was prepared and heated to obtain a polymer hydrogel; the polymer hydrogel and an imidazole halide ion compound were subjected to a solvent exchange reaction to obtain the supramolecular ionic gel.

[0031] After coating the supramolecular ionic gel onto the surface of the first carrier transport layer, an annealing process is performed to obtain a passivation layer.

[0032] A perovskite light-absorbing layer is formed on the surface of the passivation layer;

[0033] A second carrier transport layer is formed on the surface of the perovskite light-absorbing layer;

[0034] A second transparent conductive layer is formed on the surface of the second carrier transport layer;

[0035] A metal electrode is formed on the surface of the second transparent conductive layer;

[0036] or,

[0037] A first transparent conductive layer is formed on the substrate surface;

[0038] A first carrier transport layer is formed on the surface of the first transparent conductive layer;

[0039] A perovskite light-absorbing layer is formed on the surface of the first carrier transport layer;

[0040] An aqueous solution containing the polymer was prepared and heated to obtain a polymer hydrogel; the polymer hydrogel and an imidazole halide ion compound were subjected to a solvent exchange reaction to obtain the supramolecular ionic gel.

[0041] After coating the supramolecular ionic gel onto the surface of the perovskite light-absorbing layer, an annealing treatment is performed to obtain a passivation layer.

[0042] A second carrier transport layer is formed on the surface of the passivation layer;

[0043] A second transparent conductive layer is formed on the surface of the second carrier transport layer;

[0044] A metal electrode is formed on the surface of the second transparent conductive layer.

[0045] In the preparation method provided by the present invention, supramolecular ionic gel can only be prepared by solvent exchange reaction of polymer hydrogel and imidazole halide ion compound. If the ionic gel is prepared by simple physical mixing, it does not have supramolecular effect and the above-mentioned supramolecular ionic gel cannot be obtained.

[0046] Preferably, the concentration of the aqueous solution containing the polymer is 0.2-0.4 g / mL, for example, it can be 0.2 g / mL, 0.22 g / mL, 0.25 g / mL, 0.28 g / mL, 0.3 g / mL, 0.32 g / mL, 0.35 g / mL, 0.38 g / mL, 0.4 g / mL, etc.

[0047] Preferably, the heating temperature is 90-98℃, for example, 90℃, 92℃, 95℃, 98℃, etc.; the heating time is 1.5-3h, for example, 1.5h, 2h, 2.5h, 3h, etc.

[0048] Preferably, the mass of water in the polymer hydrogel is 1-3g, for example, it can be 1g, 1.2g, 1.5g, 1.8g, 2g, 2.2g, 2.5g, 2.8g, 3g, etc.

[0049] Preferably, the solvent exchange reaction is carried out at a temperature of 20-40°C, for example, 20°C, 25°C, 30°C, 35°C, 40°C, etc.; and for a time of 24 hours.

[0050] In this invention, the first carrier transport layer includes a hole transport layer or an electron transport layer.

[0051] In this invention, the second carrier transport layer includes a hole transport layer or an electron transport layer.

[0052] In this invention, the material of the hole transport layer includes p-type inorganic semiconductors or p-type organic semiconductors, preferably including any one or a combination of several of the following materials: poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), 2,2',7,7'-tetratetra[N,N-di(4-methoxyphenyl)amino]-9,9'-spirodifluorene (Spiro-OMeTAD), poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), 4-butyl-N,N-diphenylaniline homopolymer (Ploy-TPD), polyvinylcarbazole (PVK), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), [3-(9H-carbazole-9-yl)ethyl]phosphonic acid (3PACz), [4-(9H-carbazole-9-yl)ethyl]phosphonic acid (4PACz), NiOx, CuI, CuSCN, etc.

[0053] In this invention, the material of the electron transport layer includes an n-type inorganic semiconductor or an n-type organic semiconductor, preferably C. 60 Any one or a combination of materials selected from PCBM, TiO2, SnO2, ZnO, or ZnO-ZnS.

[0054] In this invention, the material of the perovskite light-absorbing layer has the general formula ABX3, where A is CH3NH3. + CH(NH2)2 + Cs + or Rb + B is any one or more of the following, where B is Pb. 2+ Sn 2+ Or Ge 2+ Any one or more of them, X is Cl - ,Br - Or I - Any one or more of them.

[0055] In this invention, the solvent for preparing the precursor solution of the perovskite light-absorbing layer includes at least one of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), 1,3-dimethyl-2-imidazolinone (DMI), dimethylacetamide (DMAC), N,N-dimethylpropenylurea (DMPU), acetonitrile (ACN), or 2-mercaptoethanol (2-ME).

[0056] In this invention, the metal electrode material includes any one of Al, Au, Ag, or carbon electrodes.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] This invention provides a passivation layer. In one aspect, this invention provides a supramolecular ionic gel for perovskite solar cells. The supramolecular ionic gel constructs a supramolecular ionic network through the synergistic effect of force-induced crystallization and halide ion compounds. Specifically, the hydroxyl groups in the polymer structure can form hydrogen bonds with the carbon-hydrogen bonds in the imidazole structure, giving it good flexibility and thus providing a solid and flexible substrate for the perovskite light-absorbing layer.

[0059] On the other hand, this invention deposits it between the perovskite light-absorbing layer and the carrier transport layer. The hydroxyl groups in the polymer structure and the carbon-hydrogen bonds in the imidazole structure within this supramolecular ionic gel can form hydrogen bonds with halide ions in the perovskite material, thereby inhibiting ion migration. Furthermore, the hydroxyl groups in the polymer structure can also react with Pb in the perovskite material. 2+ The formation of supramolecular interactions ultimately inhibits the degradation of perovskite films; at the same time, the halide anions contained in the supramolecular ionic gel can also effectively fill halogen defects, thereby improving the overall quality of perovskite films. Attached Figure Description

[0060] Figure 1 A schematic diagram illustrating the interaction between supramolecular ionic gel and perovskite material provided by the present invention;

[0061] Figure 2 The XRD patterns of the perovskite films treated in Example 1 and Comparative Example 1 of this invention are shown below.

[0062] Figure 3 The images show the UV absorption spectra of the perovskite films treated in Example 1 and Comparative Example 1 of this invention.

[0063] Figure 4 The fluorescence spectra of the perovskite films treated in Example 1 and Comparative Example 1 of this invention are shown.

[0064] Figure 5 The fluorescence lifetime spectra of the perovskite films treated in Example 1 and Comparative Example 1 of this invention are shown.

[0065] Figure 6 This is a comparison chart of the stability of perovskite solar cells in Examples 1-4 and Comparative Example 1 of the present invention;

[0066] Figure 7 The figures show the mechanical performance test results of the perovskite solar cells in Examples 1-4 and Comparative Example 1 of this invention with a bending radius of 5 mm. Detailed Implementation

[0067] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be considered as specific limitations thereof.

[0068] Example 1

[0069] This embodiment provides a perovskite solar cell, which includes a PEN / ITO substrate, a first ITO transparent conductive layer, an electron transport layer, a passivation layer, a perovskite light-absorbing layer, a hole transport layer, a second ITO transparent conductive layer, and a gold electrode, stacked sequentially. The passivation layer is made of supramolecular ionogel, which is composed of polyvinyl alcohol (PVA) and 1-ethyl-3-methylimidazolium bromide. The molecular weight of PVA is 198,000, and the mass ratio of PVA to 1-ethyl-3-methylimidazolium bromide is 1:1.

[0070] This embodiment also provides a perovskite solar cell and its fabrication method, the fabrication method being as follows:

[0071] (1) Clean the PEN / ITO substrate by ultrasonic cleaning with detergent, deionized water, acetone and anhydrous ethanol in sequence, and then drying it with a nitrogen gun; the ultrasonic cleaning power is 100Hz and the ultrasonic cleaning time is 15min.

[0072] (2) An electron transport layer was deposited on the ITO surface by spin coating. Specifically, in air, a SnO2 nanocolloid solution with a concentration of 3.67% was spin-coated onto the ITO surface. The spin coating conditions were: spin coating at a rate of 4000 rpm for 30 s, followed by annealing on a hot plate at 150°C for 30 min, with a thickness of 25 nm.

[0073] (3) Place 1g of PVA (molecular weight 198000) powder in 4g of water, heat to 95℃ and stir continuously for 2h to evaporate the water until the water content is 2g to obtain polymer hydrogel; then add 1g of 1-ethyl-3-methylimidazolium bromide to the above polymer hydrogel and stir continuously for 24h until it is completely dissolved to obtain supramolecular ionic gel.

[0074] 120 μL of the above supramolecular ionic gel was spin-coated and annealed sequentially to form a passivation layer with a thickness of 3 nm on the upper surface of the electron transport layer. The spin-coating conditions were: spin-coating at a rate of 3000 rpm for 45 s, followed by annealing at 100 °C for 25 min.

[0075] (4) Preparation of a perovskite light-absorbing layer, specifically including:

[0076] MAI, FAI, MACl, and PbI2 were dissolved in a mixed solvent composed of dimethyl sulfoxide (DMSO) and dimethylformamide (DMF). The solution was heated at 70°C and stirred continuously for 1 hour to ensure complete dissolution, thus obtaining a perovskite precursor solution. The concentration ratio of FAI:MAI:MACl was 0.95:0.05:0.14, the concentration of both FAI and PbI2 was 1.5 mol / L, and the volume ratio of DMSO to DMF in the mixed solvent was 1:9.

[0077] The perovskite precursor solution was spin-coated onto the passivation layer at 5000 rpm for 50 seconds, followed by annealing at 120°C for 15 minutes to crystallize and form a FA layer with a thickness of 550 nm. 0.95 MA 0.05 PbI3 perovskite light-absorbing layer.

[0078] (5) Deposit a hole transport layer on the surface of the perovskite light-absorbing layer. Specifically, in a glove box, spin-coat a pre-prepared hole transport layer Spiro-OMeTAD solution (concentration of 72.3 mg / mL) on the surface of the perovskite light-absorbing layer. The spin-coating conditions are: spin-coat at a speed of 3000 rpm for 30 s and a thickness of 150 nm.

[0079] (6) Fabrication of a metal electrode on the hole transport layer surface: The prepared sample is placed on a pre-prepared mask plate, and the gold electrode is evaporated. The vacuum degree in the evaporation chamber is 1.0 × 10⁻⁶. -4 Pa, evaporation rate is The thickness is 80nm.

[0080] from Figure 1 It can be seen that the supramolecular ionic gel constructs a supramolecular ionic network through the synergistic effect between force-induced crystallization and imidazole bromide ionic compounds, thus exhibiting good flexibility.

[0081] Example 2

[0082] The difference between this embodiment and Example 1 is that 1-ethyl-3-methylimidazolium bromide is replaced with an equal amount of 1-butyl-3-methylimidazolium bromide; all other aspects are the same as in Example 1.

[0083] Example 3

[0084] The difference between this embodiment and Example 1 is that 1-ethyl-3-methylimidazolium bromide is replaced with an equal amount of 1-decyl-3-methylimidazolium bromide; all other aspects are the same as in Example 1.

[0085] Example 4

[0086] The difference between this embodiment and Example 1 is that 1-ethyl-3-methylimidazolium bromide is replaced with an equal amount of 1-hexadecyl-3-methylimidazolium bromide, while all other aspects are the same as in Example 1.

[0087] Example 5

[0088] The difference between this embodiment and Embodiment 1 is that the spin coating conditions in the passivation layer preparation method are changed to: spin coating at a rate of 1500 rpm for 45 s, followed by annealing at 100°C for 25 min. At this time, the thickness of the passivation layer is 5 nm. All other conditions are the same as in Embodiment 1.

[0089] Example 6

[0090] The difference between this embodiment and Embodiment 1 is that the spin coating conditions in the passivation layer preparation method are changed to: spin coating at a rate of 4000 rpm for 45 s, followed by annealing at 100°C for 25 min. At this time, the thickness of the passivation layer is 2 nm. All other conditions are the same as in Embodiment 1.

[0091] Example 7

[0092] The difference between this embodiment and Embodiment 1 is that the spin coating conditions in the passivation layer preparation method are changed to: spin coating at a rate of 1000 rpm for 45 s, followed by annealing at 100°C for 25 min. At this time, the thickness of the passivation layer is 6 nm. All other conditions are the same as in Embodiment 1.

[0093] Example 8

[0094] The difference between this embodiment and Embodiment 1 is that in the passivation preparation method, the spin coating conditions are changed to: spin coating at a rate of 5000 rpm for 45 s, followed by annealing at 100°C for 25 min, at which time the thickness of the passivation layer is 1.5 nm, and all other conditions are the same as in Embodiment 1.

[0095] Example 9

[0096] The difference between this embodiment and Example 1 is that the mass ratio of polyvinyl alcohol to 1-ethyl-3-methylimidazolium bromide is 0.1:1, while all other aspects are the same as in Example 1.

[0097] Example 10

[0098] The difference between this embodiment and Example 1 is that the mass ratio of polyvinyl alcohol to 1-ethyl-3-methylimidazolium bromide is 3:1, while all other aspects are the same as in Example 1.

[0099] Example 11

[0100] The difference between this embodiment and Example 1 is that 1g of polyvinyl alcohol was dissolved in 2g of water, and 120μL of this solution was spin-coated onto the SnO2 layer at a speed of 3000rpm for 45s, followed by annealing at 100℃ for 25min; then 1g of 1-ethyl-3-methylimidazolium bromide was dissolved in 2.5mL of methanol, and 120μL of this solution was spin-coated again at a speed of 3000rpm for 45s, followed by annealing at 80℃ for 25min. All other aspects are the same as in Example 1.

[0101] Comparative Example 1

[0102] The difference between this comparative example and Example 1 is that no passivation layer is provided; otherwise, they are the same as Example 1.

[0103] Comparative Example 2

[0104] This comparative example provides a polyvinyl alcohol passivation layer.

[0105] Comparative Example 3

[0106] This comparative example provides a 1-ethyl-3-methylimidazolium bromide passivation layer.

[0107] Test conditions

[0108] The perovskite solar cells provided in Examples 1 to 11 and Comparative Examples 1 to 3 were tested using the following methods:

[0109] The perovskite light-absorbing layer was subjected to X-ray diffraction spectroscopy, ultraviolet spectroscopy, fluorescence spectroscopy, and fluorescence lifetime tests, respectively. The test methods are as follows:

[0110] X-ray diffraction spectroscopy: using Cu Kα As an X-ray source, the scanning range is 2θ = 5°-40°, the scanning speed is 5° / min, and the θ-2θ scanning mode is mainly used to scan and test perovskite thin film samples.

[0111] Ultraviolet spectroscopy testing: The measurement range for ultraviolet light is 400-900 nm;

[0112] Fluorescence testing: The steady-state fluorescence spectrum of the perovskite absorbing layer was tested using a xenon lamp (Xe 900) with a wavelength of 500 nm.

[0113] Fluorescence lifetime test: Fluorescence lifetime was measured using a picosecond pulsed laser (EPL 405).

[0114] The perovskite solar cells provided in the examples and comparative examples were subjected to performance tests. The JV performance of the solar cell device was mainly measured by the following four parameters: power conversion efficiency (PCE), short-circuit current density (Jsc), open-circuit voltage (Voc), and fill factor (FF).

[0115] This invention uses a solar energy simulation testing system for measurement. The light source is a 500W xenon lamp solar spectrum simulator, calibrated with a standard silicon cell KG-5, under a solar intensity (AM 1.5G: 100mW / cm²). 2 Measurements are performed under the following conditions: A continuously varying voltage (-0.2V-1.3V) is applied across the battery terminals, and the battery's output current is measured (using a Keithley 2400 power supply). The product of these two measurements yields the JV test curve, which displays the photoelectric conversion efficiency of the device under different conditions.

[0116] The test results are shown in Table 1:

[0117] Table 1

[0118]

[0119]

[0120] As can be seen from Table 1, Examples 1-6 show that the perovskite solar cells prepared after the above-mentioned supramolecular ion gel passivation layer treatment have significantly improved open-circuit voltage, short-circuit current, fill factor and photoelectric conversion efficiency.

[0121] When the thickness of the supramolecular ionic gel passivation layer is too thin (Example 8), the supramolecular ionic gel interacts with the [PbI6] in the perovskite film through hydrogen bonds and supramolecular interactions. 4- Reduced tight bonding leads to a deterioration in the quality of the perovskite film and a decrease in battery efficiency; when the thickness of the supramolecular ionogel layer is too thick (Example 7), it may hinder carrier transport, thereby affecting battery efficiency.

[0122] When the polyvinyl alcohol content is too low (Example 9), the number of hydrogen bonds formed between polyvinyl alcohol and halide ions in the perovskite film, and the relationship with [PbI6], are affected. 4- Pb in 2+The supramolecular interactions formed are reduced, and lead defects cannot be effectively passivated, resulting in lower quality perovskite films and a corresponding decrease in the efficiency of the prepared batteries. When the content of polyvinyl alcohol is too high (Example 10), a large number of organic chains will severely hinder carrier transport, leading to a decrease in battery efficiency.

[0123] When polyvinyl alcohol and 1-ethyl-3-methylimidazolium bromide are deposited sequentially (Example 11), there is no solvent exchange reaction, which greatly weakens the interaction between polyvinyl alcohol, 1-ethyl-3-methylimidazolium bromide and perovskite film, resulting in a serious decrease in battery efficiency.

[0124] Compared to Example 1, when only polyvinyl alcohol (Comparative Example 2) was used as the passivation layer material, although polyvinyl alcohol could passivate lead defects to some extent, its poor conductivity severely affected carrier transport, leading to a decrease in battery efficiency. When only 1-ethyl-3-methylimidazolium bromide (Comparative Example 3) was used as the passivation layer material, the lack of polyvinyl alcohol as a flexible framework significantly reduced the interaction between the passivation layer and the perovskite film, thus affecting the battery's bending performance and efficiency. Figure 2 It can be seen that the XRD patterns of the unmodified perovskite films and those treated with supramolecular ionogel maintain consistent diffraction peak positions, with no other extraneous peaks. Furthermore, the relative height of the PbI2 diffraction peak in the perovskite films is significantly reduced after supramolecular ionogel treatment, further indicating that the abundant hydroxyl groups in the polyvinyl alcohol in the supramolecular ionogel can passivate Pb defects, thereby reducing lead defects and decreasing non-radiative recombination.

[0125] from Figure 3 It can be seen that FA after treatment with supramolecular ionogel 0.95 MA 0.05 The absorption peak of the PbI3 perovskite film shows a slight red shift, mainly because this supramolecular ionogel can interact with [PbI6] in the perovskite material through hydrogen bonding and supramolecular interactions. 4- The close bonding forms a physically cross-linked structure, thereby enhancing the interaction between the supramolecular ionogel and the perovskite material. This not only inhibits phase transitions but also effectively promotes the crystallization of the perovskite film, resulting in a larger size of the final perovskite material. Simultaneously, after treatment, FA... 0.95 MA 0.05 The fluorescence spectrum of PbI3 thin films (e.g.) Figure 4 The emission peak of ) is significantly improved, and the fluorescence lifetime (e.g.) is also significantly improved. Figure 5 The perovskite film also showed significant enhancement, indicating that defects were reduced and the film quality was further improved after treatment with supramolecular ionogel.

[0126] fromFigure 6 It can be seen that the stability of the perovskite solar cell treated with supramolecular ionogel can still maintain more than 90% of the initial value after 1000 hours, while the untreated perovskite solar cell decays faster. This is mainly because the supramolecular ionogel can interact with [PbI6] in the perovskite through hydrogen bonds and supramolecular interactions. 4- They are tightly bound together, forming a physically cross-linked structure, while the gel contains Br - It can also effectively fill halogen defects, thereby improving film quality. From Figure 7 It can be seen that the bending performance is significantly improved after treatment with supramolecular ionic gel. This is because the supramolecular ionic gel constructs a supramolecular ionic network through the synergistic effect between force-induced crystallization and imidazole bromide ionic compounds, thus giving it good flexibility.

[0127] The applicant declares that the present invention is illustrated by the above embodiments, but the present invention is not limited to the above process steps, that is, it does not mean that the present invention must rely on the above process steps to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials used in the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A perovskite solar cell, characterized in that, The perovskite solar cell includes a substrate, a first transparent conductive layer, a first carrier transport layer, a passivation layer, a perovskite light-absorbing layer, a second carrier transport layer, a second transparent conductive layer, and a metal electrode stacked together. The first carrier transport layer and the second carrier transport layer are respectively disposed on opposite sides of the perovskite light-absorbing layer. The passivation layer is disposed between the perovskite light-absorbing layer and the first carrier transport layer, and / or the passivation layer is disposed between the perovskite light-absorbing layer and the second carrier transport layer. The material of the passivation layer includes a supramolecular ionic gel, which is composed of a polymer and an imidazole halide ion compound.

2. The perovskite solar cell according to claim 1, characterized in that, The polymer includes polyvinyl alcohol; The polymer has a molecular weight of 50,000 to 300,000, preferably 180,000 to 230,000.

3. The perovskite solar cell according to claim 1 or 2, characterized in that, The imidazole halide ion compound includes a 1-alkyl-2,3-alkylimidazolium halide salt having the structure shown in Formula 1: Among them, R1, R2, and R3 are each independently selected from hydrogen, C1-C15 straight-chain alkyl groups, or C2-C15 alkenyl groups, Y - Ions selected from Cl - ,Br - Or I - Any one of them.

4. The perovskite solar cell according to claim 3, characterized in that, The imidazole halide ion compounds include 1-ethyl-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium bromide, 1-decyl-3-methylimidazolium bromide, 1-hexadecyl-3-methylimidazolium bromide, 1,2-dimethyl-3-ethylimidazolium bromide, 1-propyl-2,3-dimethylimidazolium bromide, 1-hexyl-2,3-dimethylimidazolium bromide, 1-decyl-2,3-dimethylimidazolium bromide, 1-ethyl-2,3-dimethylimidazolium bromide, and 1-ethyl-2,3-dimethylimidazolium bromide. The imidazole chloride, 1-ethyl-2,3-dimethylimidazolium iodide, 1-dodecyl-2,3-dimethylimidazolium bromide, 1,3-decyl-2-methylchloroimidazoline, 1-vinyl-3-butylimidazolium bromide, 1-vinyl-3-ethylimidazolium bromide, 1-allyl-3-vinylimidazolium bromide, 1-allyl-2,3-dimethylimidazolium bromide, 1-allyl-2,3-dimethylimidazolium iodide, or 1-vinyl-3-ethylimidazolium iodide, or any one or a combination of at least two of these.

5. The perovskite solar cell according to any one of claims 1-4, characterized in that, The mass ratio of the polymer to the imidazole halide ion compound is (0.2-1.5):1, preferably (0.8-1.2):

1.

6. The perovskite solar cell according to any one of claims 1-5, characterized in that, The thickness of the passivation layer is 2-5 nm; The thickness of the perovskite light-absorbing layer is 300-700 nm; The perovskite light-absorbing layer contains divalent lead cations.

7. The perovskite solar cell according to any one of claims 1-6, characterized in that, The substrate includes a flexible substrate material; The flexible substrate material includes at least one of polyethylene terephthalate, polyethylene naphthalate, or colorless polyimide.

8. A method for preparing a perovskite solar cell according to any one of claims 1-7, characterized in that, The method includes the following steps: A first transparent conductive layer is formed on the substrate surface; A first carrier transport layer is formed on the surface of the first transparent conductive layer; An aqueous solution containing the polymer was prepared and heated to obtain a polymer hydrogel; the polymer hydrogel and an imidazole halide ion compound were subjected to a solvent exchange reaction to obtain the supramolecular ionic gel. After coating the supramolecular ionic gel onto the surface of the first carrier transport layer, an annealing process is performed to obtain a passivation layer. A perovskite light-absorbing layer is formed on the surface of the passivation layer; A second carrier transport layer is formed on the surface of the perovskite light-absorbing layer; A second transparent conductive layer is formed on the surface of the second carrier transport layer; A metal electrode is formed on the surface of the second transparent conductive layer; or, A first transparent conductive layer is formed on the substrate surface; A first carrier transport layer is formed on the surface of the first transparent conductive layer; A perovskite light-absorbing layer is formed on the surface of the first carrier transport layer; An aqueous solution containing the polymer was prepared and heated to obtain a polymer hydrogel; the polymer hydrogel and an imidazole halide ion compound were subjected to a solvent exchange reaction to obtain the supramolecular ionic gel. After coating the supramolecular ionic gel onto the surface of the perovskite light-absorbing layer, an annealing treatment is performed to obtain a passivation layer. A second carrier transport layer is formed on the surface of the passivation layer; A second transparent conductive layer is formed on the surface of the second carrier transport layer; A metal electrode is formed on the surface of the second transparent conductive layer.

9. The method according to claim 8, characterized in that, The concentration of the aqueous solution containing the polymer is 0.2-0.4 g / mL; The heating temperature is 90-98℃, and the time is 1.5-3 hours; The polymer hydrogel contains 1-3g of water.

10. The method according to claim 8 or 9, characterized in that, The solvent exchange reaction is carried out at a temperature of 20-40℃ for 24 hours.

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