A perovskite solar cell passivated by a supramolecular metal complex and its preparation method

Abstract

This invention relates to the field of solar cell technology, and discloses a perovskite solar cell passivated with a supramolecular metal complex and its preparation method. The perovskite solar cell, from bottom to top, comprises a transparent conductive substrate layer, a hole transport layer, a perovskite light-absorbing layer, a surface passivation layer, an electron transport layer, an interface buffer layer, and an electrode layer. The surface passivation layer is made of a supramolecular metal complex, with the general structural formula M·N, where M is a supramolecular material and N is a metal fluoride. The supramolecular metal complex surface passivation layer used in this invention forms a dense network structure through in-situ self-assembly on the perovskite film surface via strong interactions such as hydrogen bonds and coordination bonds. This effectively passivates interface and grain boundary defects, suppresses non-radiative recombination and ion migration, and simultaneously improves interface charge transport and carrier migration capabilities, significantly enhancing the photoelectric conversion efficiency and long-term operational stability of the perovskite solar cell.

Description

Technical Field

[0001] This invention relates to the field of solar cell technology, and in particular to a perovskite solar cell passivated by supramolecular metal complexes and its preparation method. Background Technology

[0002] With the global energy structure shifting towards clean and renewable energy, photovoltaic technology, as a core means of efficiently utilizing solar energy, has received widespread attention. Among them, perovskite solar cells, as a representative of emerging photovoltaic technologies, have rapidly become a research hotspot in the photovoltaic field due to the excellent photoelectric properties of their core organic-inorganic hybrid perovskite materials. Organic-inorganic hybrid perovskite materials have outstanding advantages such as a wide tunable bandgap, long carrier lifetime, low exciton binding energy, and high carrier mobility, providing a solid foundation for improving the photoelectric conversion efficiency of cells. Currently, perovskite cells prepared in the laboratory have achieved a certified power conversion efficiency of 27.3%, demonstrating enormous potential for commercial applications.

[0003] Significant breakthroughs have been achieved in the performance of perovskite solar cells, but key bottlenecks hindering their large-scale commercial application remain unresolved, with insufficient cell stability and unclear degradation mechanisms being the core issues. Specifically, during the fabrication of perovskite films, numerous grain boundaries inevitably form. These boundaries not only become primary channels for ion migration within the perovskite material but also exacerbate device performance degradation. Simultaneously, the numerous dangling bond defects on the film surface significantly increase nonradiative recombination losses of charge carriers, shortening carrier lifetime and leading to a decrease in photoelectric conversion efficiency. Furthermore, the poor chemical stability of perovskite films makes them susceptible to corrosion from environmental factors such as humidity and oxygen, further accelerating film degradation and ultimately causing a substantial decrease in cell efficiency, reduced stability, and a pronounced hysteresis effect, severely impacting the long-term performance of the device. In addition to defects in the film itself, interface problems between the functional layers of perovskite solar cells are equally significant. Defects at the interfaces and imperfect energy level alignment inevitably lead to severe nonradiative recombination, causing open-circuit voltage losses and further restricting the improvement of overall cell performance.

[0004] Therefore, how to prepare high-quality perovskite thin films with low defect density, while simultaneously constructing interfaces with precise energy level alignment, efficient and smooth charge transport, and a robust and reliable structure, to solve key technical problems such as low efficiency, poor stability, and significant hysteresis in perovskite solar cells, has become an urgent need to promote the commercial application of perovskite photovoltaic technology. For example, existing Chinese patent literature, publication number CN121335342A, discloses a perovskite solar cell device and its preparation method. A passivation layer made of diphenylamine passivating agents is placed between the electron transport layer and the perovskite light-absorbing layer. Through the synergistic effect of various unique functional groups, the interface structure is stabilized, defect states are reduced, and the stability and efficiency of the perovskite solar cell device are improved. Summary of the Invention

[0005] This invention addresses the core problems of existing perovskite solar cells, such as numerous grain boundary defects, interfacial energy level mismatch, and severe ion migration. It provides a perovskite solar cell passivated with a supramolecular metal complex and its preparation method. A supramolecular metal complex surface passivation layer is inserted between the perovskite light-absorbing layer and the electron transport layer. On one hand, the metal fluoride in the supramolecular metal complex easily induces downward band bending at the perovskite interface, reducing electron-selective contact resistance, promoting interfacial electron extraction, and spatially separating the electron transport layer from the perovskite surface. This blocks the interfacial charge recombination channel dominated by bandgap states, inhibits the formation of induced defect states, and eliminates the interfacial electron extraction barrier, thereby significantly improving the efficiency of the perovskite solar cell. On the other hand, based on the heteroatom functionalization strategy and cavity size effect, the supramolecular metal complex can form strong interactions with uncoordinated ions in the perovskite layer. Through multi-mode host-guest recombination, synergistic passivation of surface and bulk defects in the perovskite film is achieved, significantly improving the stability of the perovskite solar cell.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A perovskite solar cell passivated with a supramolecular metal complex comprises, from bottom to top, a transparent conductive substrate layer, a hole transport layer, a perovskite light-absorbing layer, a surface passivation layer, an electron transport layer, an interface buffer layer, and an electrode layer. The surface passivation layer is made of a supramolecular metal complex with the general structural formula M·N, where M is a supramolecular material, including one of crown ethers, cryptethers, DNA, cyclodextrin, calixarene, calixpyrrole, calixcarbazole, cucurbitalurea, and columnar aromatics, and N is a metal fluoride, including one of LiF, CsF, NaF, RbF, KF, MgF2, PbF2, SnF2, GeF2, BaF2, ZnF2, LaF3, GdF3, CdF2, SrF2, GaF3, and InF3.

[0007] This invention provides a new approach for the controllable fabrication of high-efficiency and stable perovskite solar cells. Inserting a supramolecular metal complex surface passivation layer between the perovskite light-absorbing layer and the electron transport layer effectively improves the efficiency and stability of perovskite solar cells, mainly in the following aspects: (1) Supramolecular metal complexes can precisely control the interfacial energy level arrangement between perovskite and electron transport layer, induce the perovskite interface to form a downward band bending that is conducive to electron extraction, reduce the electron extraction barrier, improve the interfacial charge transport efficiency, reduce the accumulation of interfacial charge, effectively passivate the charge trap defects at the perovskite bulk phase and grain boundaries, improve the crystallinity and density of perovskite films, reduce non-radiative recombination loss, and achieve a significant improvement in the photoelectric conversion efficiency of the battery.

[0008] (2) The passivation layer on the surface of supramolecular metal complex can effectively regulate the nucleation and growth process of perovskite. It induces the directional growth of perovskite grains through hydrogen bonding and coordination between molecules, reduces the generation of defects during grain nucleation, fills the gaps between grains, effectively eliminates weak links at grain boundaries, significantly improves the crystal quality of perovskite, thereby enhancing the adhesion between the perovskite film and the charge transport layer, alleviating microcracks caused by internal stress in the film, inhibiting the generation of induced defect states, and improving the intrinsic stability and photoelectric properties of the perovskite film.

[0009] (3) The supramolecular metal complexes achieve dual fixation of insufficiently coordinated metal ions and halide ions in perovskite through chelation, effectively inhibiting the migration and segregation of halide ions in perovskite, significantly reducing the degradation rate of perovskite films under harsh external conditions such as light and thermal stress, and significantly enhancing the photothermal stability of perovskite solar cells.

[0010] (4) The ultrathin supramolecular metal complex passivation layer can effectively isolate the direct contact between the perovskite and the electron transport layer, suppress the formation of induced state traps at the interface, reduce the interface side reactions between the electron transport layer and the perovskite, and improve the interface bonding and compatibility, thus avoiding the rapid degradation of battery performance caused by interface deterioration and charge accumulation, and effectively extending the service life of the battery.

[0011] Further preferred, the supramolecular metal complex is 4-tert-butylcalix[6]arene·lithium fluoride.

[0012] Preferably, the perovskite light-absorbing layer has the general structural formula ABX3, where A is Rb + Cs + MA + or FA + B is Pb 2+ Sn 2+ Or Ge 2+ X is I - ,Br - or Cl -.

[0013] Preferably, the transparent conductive substrate layer is FTO glass, ITO glass, ITO / PET, ITO / PEN, or ITO / PI; the hole transport layer is nickel oxide or doped nickel oxide, 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), (4-(3,6-dimethyl-9H-carbazole-9-yl)butyl)phosphonic acid (Me-4PACz), or (2-(9H-carbazole-9-yl)ethyl)phosphonic acid (2PACz). The electron transport layer is a fullerene or its derivative, including C60, C70 or PC60M, etc.; the interface buffer layer is copper bath, tin oxide, zinc oxide, yttrium oxide, cerium oxide, tungsten oxide, titanium oxide or niobium oxide; the electrode layer is Cu, Ag, Au, Mo, Ni, Sb, Bi, ITO (tin-doped indium oxide), IZO (zinc-doped indium oxide), AZO (aluminum-doped zinc oxide), IWO (tungsten-doped indium oxide) or ICO (cerium-doped indium oxide).

[0014] Preferably, the surface passivation layer has a thickness of 0.1~80nm; the perovskite light-absorbing layer has a thickness of 100~2000nm; the electron transport layer has a thickness of 1~100nm; the interface buffer layer has a thickness of 1~100nm; and the electrode layer has a thickness of 10~10000nm.

[0015] The present invention also provides a method for preparing the above-mentioned perovskite solar cell, comprising the following steps: S1. Deposit a hole transport layer on a transparent conductive substrate; S2. Perovskite powder is dissolved in an organic solvent, stirred and clarified to form a perovskite precursor solution. The perovskite precursor solution is coated or printed on the hole transport layer, and after heat treatment, a perovskite light-absorbing layer is obtained. S3. The supramolecular metal complex is dissolved in an organic solvent, stirred and clarified to obtain a supramolecular metal complex solution. The supramolecular metal complex solution is coated on the surface of the perovskite light-absorbing layer, and a surface passivation layer is obtained after heat treatment. S4. An electron transport layer, an interface buffer layer, and an electrode layer are sequentially deposited on the surface passivation layer to obtain a perovskite solar cell.

[0016] The supramolecular metal complex surface passivation layer introduced in the perovskite solar cell of this invention can be made by a simple solution processing method, which is highly compatible with the existing mainstream slot coating process. It does not require major modifications to existing production lines, has low preparation cost, simple process, and wide applicability.

[0017] Preferably, the organic solvent used to prepare the supramolecular metal complex solution is one or more of isopropanol, chlorobenzene, ethyl acetate, butanol, chloroform, benzene, isobutanol, sec-butanol, dichlorobenzene, dimethylbenzene, toluene, acetonitrile, dichloroethane, anisole, and butyl acetate mixed in any proportion; the organic solvent used to prepare the perovskite precursor solution is one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-methyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone, 1,3-dimethyl-2-imidazolinone, 2-methoxyethanol, and acetonitrile mixed in any proportion.

[0018] Further optimization involves using an organic solvent for preparing a supramolecular metal complex solution, which is a mixture of chlorobenzene and chloroform in a volume ratio of 9:1; and an organic solvent for preparing a perovskite precursor solution, which is a mixture of acetonitrile, N,N-dimethylformamide, and 1,3-dimethyl-2-imidazolinone in a volume ratio of 3:6.4:0.6.

[0019] Preferably, the concentration of the supramolecular metal complex solution is 0.001–100 mg / mL; and the concentration of the perovskite precursor solution is 0.1–3 mol / L.

[0020] Further preferably, the concentration of the supramolecular metal complex solution is 0.08 mg / mL; and the concentration of the perovskite precursor solution is 1.55 mol / L.

[0021] Preferably, the preparation process of the supramolecular metal complex is as follows: the supramolecular material and the metal fluoride are mixed in tetrahydrofuran, and the reaction is continuously stirred. After the reaction is completed, the mixture is filtered, and the filtrate is concentrated under reduced pressure until it is dried to obtain a crude product. The crude product is recrystallized multiple times to obtain the supramolecular metal complex.

[0022] The supramolecular metal complex preparation process used in this invention is simple, consisting of a liquid-phase reaction between supramolecular materials and metal fluorides.

[0023] Preferably, the heat treatment temperature of the surface passivation layer is 30–200°C and the time is 1–60 min; the heat treatment temperature of the perovskite light-absorbing layer is 30–300°C and the time is 5–120 min.

[0024] Preferably, the electron transport layer is deposited by vapor deposition; the interface buffer layer is deposited by coating, printing, vapor deposition, sputtering, reactive plasma deposition, chemical vapor deposition, coating or printing; the electrode layer is deposited by vapor deposition, sputtering, chemical vapor deposition, coating or printing.

[0025] Therefore, the present invention has the following beneficial effects: (1) The passivation effect of the supramolecular metal complex on perovskite in this invention is based on physical chelation, interface energy level regulation, and grain boundary defect filling. The introduction of supramolecular metal complex generates strong interactions such as hydrogen bonds and coordination bonds, and forms a dense network structure in situ on the surface of the perovskite film. This effectively passivates the interface and grain boundary defects, suppresses nonradiative recombination and ion migration, releases residual stress at the interface, and improves the interface charge transport and carrier migration capabilities, thereby significantly improving the photoelectric conversion efficiency and long-term operational stability of the perovskite battery. (2) Moreover, the supramolecular metal complex does not undergo harmful chemical side reactions with the perovskite active layer, and will not introduce new charge traps or structural defects. Furthermore, the passivation material is chemically stable and is not easily decomposed, volatilized or migrated, which can achieve long-term passivation of perovskite batteries and avoid the gradual decline in battery performance caused by the failure of passivation materials and the decay of passivation effect. (3) The surface passivation layer composed of supramolecular metal complexes can be introduced into perovskite solar cells through a simple solution processing method. It is highly compatible with the existing mainstream slit coating process of perovskite solar cells, without the need for major modifications to existing production lines. The preparation cost is low and the process is simple. It can also be extended to multi-junction solar cells such as perovskite-crystalline silicon tandem and perovskite-perovskite tandem. It has a wide range of applications and good prospects for industrial promotion. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the perovskite solar cell of the present invention.

[0027] Figure 2 This is a schematic diagram of the structure of the supramolecular metal complex used in this invention.

[0028] Figure 3 These are scanning electron microscope (SEM) images of the perovskite solar cells of Example 1 and Comparative Examples 1-3 of the present invention.

[0029] Figure 4 The images show the steady-state fluorescence spectra of the perovskite solar cells of Example 1 and Comparative Examples 1-3 of this invention.

[0030] In the figure: 1. Transparent conductive substrate layer; 2. Hole transport layer; 3. Perovskite light-absorbing layer; 4. Surface passivation layer; 5. Electron transport layer; 6. Interface buffer layer; 7. Electrode layer. Detailed Implementation

[0031] The present invention will now be further described with reference to the accompanying drawings and specific embodiments. Example 1

[0032] like Figure 1 As shown, a perovskite battery includes, from bottom to top, a transparent conductive substrate layer 1, a hole transport layer 2, a perovskite light-absorbing layer 3, a surface passivation layer 4, an electron transport layer 5, an interface buffer layer 6, and an electrode layer 7. The surface passivation layer 4 is made of a supramolecular metal complex, and the general structural formula of the supramolecular metal complex is 4-tert-butylcalix[6]arene·lithium fluoride.

[0033] The method for preparing this perovskite solar cell includes the following steps: Step 1: Synthesis of supramolecular metal complex 4-tert-butylcalix[6]arene·lithium fluoride: 973.37 mg (1 mmol) of 4-tert-butylcalix[6]arene and 259.39 mg (10 mmol) of lithium fluoride (LiF) were weighed and added to 40 mL of anhydrous tetrahydrofuran. The reaction was carried out under nitrogen protection and stirred continuously at room temperature for 48 hours. Unreacted lithium fluoride was then filtered off, and the filtrate was concentrated under reduced pressure until dry to obtain a crude product. The crude product was recrystallized from anhydrous acetonitrile to obtain approximately 1 g of pure 4-tert-butylcalix[6]arene·lithium fluoride supramolecular metal complex (see schematic diagram). Figure 2 White solid powder.

[0034] Step 2: Fabrication of an inverse perovskite solar cell containing a supramolecular metal complex surface passivation layer: (1) The FTO glass was ultrasonically cleaned sequentially with glass cleaning agent, ultrapure water and alcohol, and dried after cleaning to obtain a clean transparent conductive substrate layer; (2) A 0.5 mg / mL Me-4PACz ethanol solution was applied to a clean FTO glass substrate. The applied Me-4PACz layer was heat-treated at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2.7 nm. (3) Weigh CsI, MAI, FAI, and PbI2 (molar ratio of 0.1:0.1:0.8:1.03) powder and dissolve them in a mixed solvent of acetonitrile, N,N-dimethylformamide and 1,3-dimethyl-2-imidazolinone in a volume ratio of 3:6.4:0.6. After stirring and clarifying, a 1.55 mol / L perovskite precursor solution is obtained. The perovskite precursor solution is coated on the slits of the hole transport layer surface. The coated perovskite wet film is heat-treated at 110℃ for 22 min to obtain a perovskite light-absorbing layer with a thickness of 600 nm. (4) Weigh 4-tert-butylcalix[6]arene·lithium fluoride and dissolve it in a mixed solvent of chlorobenzene and chloroform in a volume ratio of 9:1. After stirring and clarifying, a supramolecular metal complex solution of 0.08 mg / mL is obtained. The supramolecular metal complex solution is coated on the slit of the perovskite light-absorbing layer. The coated supramolecular metal complex is heat-treated at 100℃ for 3 min to obtain a surface passivation layer with a thickness of 1.7 nm. (5) A 15 nm thick C60 electron transport layer, a 15 nm thick tin oxide interface buffer layer, and a 300 nm thick IZO electrode layer are sequentially deposited on the surface passivation layer to obtain an inverse perovskite solar cell containing a supramolecular metal complex surface passivation layer. Example 2

[0035] A perovskite solar cell comprises, from bottom to top, a transparent conductive substrate layer, a hole transport layer, a perovskite light-absorbing layer, a surface passivation layer, an electron transport layer, an interface buffer layer, and an electrode layer. The surface passivation layer is made of a supramolecular metal complex, and the general structural formula of the supramolecular metal complex is dibenzo-18-crown ether-6·cadmium fluoride.

[0036] The method for preparing this perovskite solar cell includes the following steps: Step 1: Synthesis of the supramolecular metal complex dibenzo-18-crown ether-6·cadmium fluoride: 360.4 mg (1 mmol) of dibenzo-18-crown ether-6 and 1504.1 mg (10 mmol) of cadmium fluoride (CdF2) were weighed and added to 40 mL of anhydrous tetrahydrofuran. The reaction was carried out under nitrogen protection and stirred continuously at room temperature for 48 hours. Unreacted cadmium fluoride was then filtered off, and the filtrate was concentrated under reduced pressure until dry to obtain a crude product. The crude product was recrystallized from anhydrous acetonitrile to obtain approximately 1.3 g of pure dibenzo-18-crown ether-6·cadmium fluoride supramolecular metal complex solid powder.

[0037] Step 2: Fabrication of an inverse perovskite solar cell containing a supramolecular metal complex surface passivation layer: (1) The FTO glass was ultrasonically cleaned sequentially with glass cleaning agent, ultrapure water and alcohol, and dried after cleaning to obtain a clean transparent conductive substrate layer; (2) A 0.5 mg / mL Me-4PACz ethanol solution was applied to a clean FTO glass substrate. The applied Me-4PACz layer was heat-treated at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2.7 nm. (3) Weigh CsI, MAI, FAI, and PbI2 (molar ratio of 0.1:0.1:0.8:1.03) powder and dissolve them in a mixed solvent of acetonitrile, N,N-dimethylformamide and 1,3-dimethyl-2-imidazolinone in a volume ratio of 3:6.4:0.6. After stirring and clarifying, a 1.55 mol / L perovskite precursor solution is obtained. The perovskite precursor solution is coated on the slits of the hole transport layer surface. The coated perovskite wet film is heat-treated at 110℃ for 22 min to obtain a perovskite light-absorbing layer with a thickness of 600 nm. (4) Weigh dibenzo-18-crown ether-6·cadmium fluoride and dissolve it in a mixed solvent of chlorobenzene and chloroform in a volume ratio of 9:1. After stirring and clarifying, a 0.1 mg / mL supramolecular metal complex solution is obtained. The supramolecular metal complex solution is coated on the slits of the perovskite light-absorbing layer. The coated supramolecular metal complex is heat-treated at 100℃ for 3 min to obtain a surface passivation layer with a thickness of 1.7 nm. (5) A 15 nm thick C60 electron transport layer, a 15 nm thick tin oxide interface buffer layer, and a 300 nm thick IZO electrode layer are sequentially deposited on the surface passivation layer to obtain an inverse perovskite solar cell containing a supramolecular metal complex surface passivation layer. Example 3

[0038] A perovskite solar cell comprises, from bottom to top, a transparent conductive substrate layer, a hole transport layer, a perovskite light-absorbing layer, a surface passivation layer, an electron transport layer, an interface buffer layer, and an electrode layer. The surface passivation layer is made of a supramolecular metal complex, and the general structural formula of the supramolecular metal complex is cyclodextrin·gadolinium fluoride.

[0039] The method for preparing this perovskite solar cell includes the following steps: Step 1: Synthesis of the supramolecular metal complex cyclodextrin·gadolinium fluoride: Weigh 1134.99 mg (1 mmol) Cyclodextrin and 2142.5 mg (10 mmol) of gadolinium fluoride (GdF3) were added to 40 mL of anhydrous tetrahydrofuran. The reaction was carried out under nitrogen protection and stirred continuously at room temperature for 48 hours. Unreacted gadolinium fluoride was then filtered off, and the filtrate was concentrated under reduced pressure until dry to obtain a crude product. The crude product was recrystallized from anhydrous acetonitrile to obtain approximately 2.7 g of pure cyclodextrin-gadolinium fluoride supramolecular metal complex (solid powder).

[0040] Step 2: Fabrication of an inverse perovskite solar cell containing a supramolecular metal complex surface passivation layer: (1) The FTO glass was ultrasonically cleaned sequentially with glass cleaning agent, ultrapure water and alcohol, and dried after cleaning to obtain a clean transparent conductive substrate layer; (2) A 0.5 mg / mL Me-4PACz ethanol solution was applied to a clean FTO glass substrate. The applied Me-4PACz layer was heat-treated at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2.7 nm. (3) Weigh CsI, MAI, FAI, and PbI2 (molar ratio of 0.1:0.1:0.8:1.03) powder and dissolve them in a mixed solvent of acetonitrile, N,N-dimethylformamide and 1,3-dimethyl-2-imidazolinone in a volume ratio of 3:6.4:0.6. After stirring and clarifying, a 1.55 mol / L perovskite precursor solution is obtained. The perovskite precursor solution is coated on the slits of the hole transport layer surface. The coated perovskite wet film is heat-treated at 110℃ for 22 min to obtain a perovskite light-absorbing layer with a thickness of 600 nm. (4) Weigh cyclodextrin·gadolinium fluoride and dissolve it in a mixed solvent of chlorobenzene and chloroform in a volume ratio of 9:1. After stirring and clarifying, a 0.16 mg / mL supramolecular metal complex solution is obtained. The supramolecular metal complex solution is coated on the slits of the perovskite light-absorbing layer. The coated supramolecular metal complex is heat-treated at 100℃ for 3 min to obtain a surface passivation layer with a thickness of 1.7 nm. (5) A 15 nm thick C60 electron transport layer, a 15 nm thick tin oxide interface buffer layer, and a 300 nm thick IZO electrode layer are sequentially deposited on the surface passivation layer to obtain an inverse perovskite solar cell containing a supramolecular metal complex surface passivation layer.

[0041] Comparative Example 1 The difference from Example 1 is that the supramolecular passivation layer replaces the surface passivation layer, that is, the passivation layer contains only the supramolecular material 4-tert-butylcalix[6] aromatic hydrocarbon.

[0042] The fabrication steps of this perovskite solar cell are as follows: (1) The FTO glass was ultrasonically cleaned sequentially with glass cleaning agent, ultrapure water and alcohol, and dried after cleaning to obtain a clean FTO glass substrate layer; (2) A 0.5 mg / mL Me-4PACz ethanol solution was applied to a clean FTO glass substrate. The applied Me-4PACz layer was heat-treated at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2.7 nm. (3) Weigh CsI, MAI, FAI, and PbI2 (molar ratio of 0.1:0.1:0.8:1.03) powder and dissolve them in a mixed solvent of acetonitrile, N,N-dimethylformamide and 1,3-dimethyl-2-imidazolinone in a volume ratio of 3:6.4:0.6. After stirring and clarifying, a 1.55 mol / L perovskite precursor solution is obtained. The perovskite precursor solution is coated on the slits of the hole transport layer surface. The coated perovskite wet film is heat-treated at 110℃ for 22 min to obtain a perovskite light-absorbing layer with a thickness of 600 nm. (4) Weigh 4-tert-butylcalix[6] aromatic hydrocarbons and dissolve them in a mixed solvent of chlorobenzene and chloroform in a volume ratio of 9:1. After stirring and clarifying, a supramolecular solution of 0.08 mg / mL is obtained. The supramolecular solution is coated on the slits of the perovskite light-absorbing layer. The coated supramolecular layer is heat-treated at 10°C for 3 min to obtain a supramolecular passivation layer with a thickness of 2.3 nm. (5) A 15 nm thick C60 electron transport layer, a 15 nm thick tin oxide interface buffer layer, and a 300 nm thick IZO electrode layer are sequentially deposited on the supramolecular passivation layer to obtain an inverse perovskite solar cell containing a supramolecular passivation layer.

[0043] Comparative Example 2 The difference from Example 1 is that the surface passivation layer is replaced by a lithium fluoride passivation layer, that is, the passivation layer contains only lithium fluoride.

[0044] The fabrication steps of this perovskite solar cell are as follows: (1) The FTO glass was ultrasonically cleaned sequentially with glass cleaning agent, ultrapure water and alcohol, and dried after cleaning to obtain a clean FTO glass substrate layer; (2) A 0.5 mg / mL Me-4PACz ethanol solution was applied to a clean FTO glass substrate. The applied Me-4PACz layer was heat-treated at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2.7 nm. (3) Weigh CsI, MAI, FAI, and PbI2 (molar ratio of 0.1:0.1:0.8:1.03) powder and dissolve them in a mixed solvent of acetonitrile, N,N-dimethylformamide and 1,3-dimethyl-2-imidazolinone in a volume ratio of 3:6.4:0.6. After stirring and clarifying, a 1.55 mol / L perovskite precursor solution is obtained. The perovskite precursor solution is coated on the slits of the hole transport layer surface. The coated perovskite wet film is heat-treated at 110℃ for 22 min to obtain a perovskite light-absorbing layer with a thickness of 600 nm. (4) A 1 nm thick lithium fluoride passivation layer is deposited on the surface of the perovskite light-absorbing layer; (5) A 15 nm thick C60 electron transport layer, a 15 nm thick tin oxide interface buffer layer, and a 300 nm thick IZO electrode layer are sequentially deposited on the passivation layer of lithium fluoride to obtain an inverse perovskite solar cell containing a lithium fluoride passivation layer.

[0045] Comparative Example 3 The difference from Example 1 is that the surface passivation layer is replaced by a combination of supramolecular passivation layer and lithium fluoride passivation layer.

[0046] The fabrication steps of this perovskite solar cell are as follows: (1) The FTO glass was ultrasonically cleaned sequentially with glass cleaning agent, ultrapure water and alcohol, and dried after cleaning to obtain a clean FTO glass substrate layer; (2) A 0.5 mg / mL Me-4PACz ethanol solution was applied to a clean FTO glass substrate. The applied Me-4PACz layer was heat-treated at 100 °C for 10 min to obtain a hole transport layer with a thickness of 2.7 nm. (3) Weigh CsI, MAI, FAI, and PbI2 (molar ratio of 0.1:0.1:0.8:1.03) powder and dissolve them in a mixed solvent of acetonitrile, N,N-dimethylformamide and 1,3-dimethyl-2-imidazolinone in a volume ratio of 3:6.4:0.6. After stirring and clarifying, a 1.55 mol / L perovskite precursor solution is obtained. The perovskite precursor solution is coated on the slits of the hole transport layer surface. The coated perovskite wet film is heat-treated at 110℃ for 22 min to obtain a perovskite light-absorbing layer with a thickness of 600 nm. (4) Weigh 4-tert-butylcalix[6] aromatic hydrocarbons and dissolve them in a mixed solvent of chlorobenzene and chloroform in a volume ratio of 9:1. After stirring and clarifying, a supramolecular solution of 0.08 mg / mL is obtained. The supramolecular solution is coated on the slit surface of the perovskite light-absorbing layer. The coated supramolecular layer is heat-treated at 100 °C for 3 min to obtain a supramolecular passivation layer with a thickness of 2.3 nm. (5) A lithium fluoride passivation layer with a thickness of 1 nm is deposited on the surface of the supramolecular passivation layer; (6) A 15 nm thick C60 electron transport layer, a 15 nm thick tin oxide interface buffer layer, and a 300 nm thick IZO electrode layer are sequentially deposited on the lithium fluoride passivation layer to obtain an inverse perovskite solar cell based on a supramolecular / metal fluoride composite passivation layer.

[0047] The performance of perovskite solar cells was tested using an AM1.5 G standard solar spectrum simulator under environmental conditions of 25°C, humidity below 30%, and a nitrogen protective atmosphere. The performance of the perovskite solar cells obtained in Examples 1-3 and Comparative Examples 1-3 was characterized, including open-circuit voltage, short-circuit current density, fill factor, photoelectric conversion efficiency, and efficiency degradation rate after 1000 hours of maximum power point tracking. The results are shown in Table 1.

[0048] Table 1. Performance parameters of devices in the examples and comparative examples As shown in Table 1, the photoelectric conversion efficiency of the inverted perovskite solar cell with the passivation layer of 4-tert-butylcalix[6]arene·lithium fluoride supramolecular metal complex is as high as 26.79%, and the efficiency of the cell only decreases by 0.4% after 1000 hours of maximum power point tracking. The device efficiency and stability are far superior to the inverted perovskite solar cells prepared in Comparative Examples 1 and 2. This shows that the supramolecular metal complex can effectively passivate the surface and grain boundary defects of the perovskite film, suppress non-radiative recombination loss, optimize the interface energy level arrangement, and at the same time construct a stable molecular barrier layer to suppress ion migration and resist external water and oxygen erosion, thereby achieving a synergistic improvement in the efficiency and stability of the perovskite cell. Moreover, the supramolecular metal complex passivation layer can effectively isolate the direct contact between the perovskite and the electron transport layer, reduce the interfacial side reactions between the electron transport layer and the perovskite, suppress the formation of induced state traps at the interface, and improve the interfacial bonding force and compatibility, avoiding the rapid degradation of the cell performance caused by interface degradation and charge accumulation, and maintaining long-term working stability.

[0049] In addition, the inverted perovskite solar cell passivated by the 4-tert-butylcalix[6]arene and lithium fluoride composite system in Comparative Example 3 achieved a photoelectric conversion efficiency of 26.13%, but the efficiency still decreased by 5.2% after 1000 hours of maximum power point tracking. This further confirms that the precise coordination structure and spatial shielding effect of supramolecular metal complexes are the core to achieving high efficiency and stability of perovskite cells. Simple physical blending is difficult to form a stable defect passivation interface and cannot simultaneously improve the efficiency and operational stability of the cells.

[0050] Perovskite solar cells using other supramolecular metal complexes, such as the inverted perovskite solar cell with a surface passivation layer of dibenzo-18-crown ether-6·cadmium fluoride supramolecular metal complex used in Example 1, have a photoelectric conversion efficiency as high as 26.48%, and the efficiency only decreases by 1.2% after 1000 hours of maximum power point tracking. The inverted perovskite solar cell with a surface passivation layer of cyclodextrin·gadolinium fluoride supramolecular metal complex used in Example 2 has a photoelectric conversion efficiency as high as 26.7%, and the efficiency only decreases by 0.7% after 1000 hours of maximum power point tracking. This shows that high photoelectric conversion efficiency and stability can also be achieved by using other supramolecular metal complexes.

[0051] like Figure 3 As shown, compared with Comparative Examples 1-3, the perovskite film in Example 1, passivated by the 4-tert-butylcalix[6]arene·lithium fluoride supramolecular metal complex, exhibits superior microstructural characteristics. The grain size of the film is significantly increased, the grains are tightly and orderly arranged, and there are no obvious pores or cracks, nor obvious lattice distortions or dislocation defects. This indicates that the supramolecular metal complex induces the directional growth of perovskite grains through intermolecular hydrogen bonds and coordination, reduces the generation of defects during grain nucleation, and fills the gaps between grains, effectively eliminating weak links at grain boundaries and significantly improving the crystallinity of perovskite.

[0052] like Figure 4 As shown, the perovskite film passivated by the supramolecular metal complex of 4-tert-butylcalix[6]arene·lithium fluoride in Example 1 had a much higher fluorescence emission intensity than that in Comparative Examples 1 and 2, indicating that the nonradiative recombination of photogenerated carriers in the perovskite film after passivation with the supramolecular metal complex was significantly suppressed. At the same time, the position of the fluorescence emission peak of the film after passivation did not show a significant red shift or blue shift, indicating that the passivation process of the supramolecular metal complex did not destroy the crystal structure of the perovskite, did not introduce impurity phases or generate lattice stress, but instead improved the crystal integrity and purity of the crystal through defect passivation, improved the separation and transport efficiency of photogenerated carriers in the perovskite, reduced the recombination loss of carriers inside the film, and directly promoted the improvement of the photoelectric conversion efficiency of the battery.

[0053] In summary, the precise coordination structure and spatial shielding effect of supramolecular metal complexes are the core mechanisms for optimizing the microstructure and improving the photoelectric performance of perovskite thin films, thereby simultaneously improving battery efficiency and stability. This further highlights the significant advantages of supramolecular metal complexes compared to simple composite passivation systems, and this technology provides a new solution for the large-scale manufacturing of perovskite batteries.

Claims

1. A perovskite solar cell passivated with a supramolecular metal complex, comprising, from bottom to top, a transparent conductive substrate layer, a hole transport layer, a perovskite light-absorbing layer, a surface passivation layer, an electron transport layer, an interface buffer layer, and an electrode layer, characterized in that, The surface passivation layer is made of a supramolecular metal complex with the general structural formula M·N, where M is a supramolecular material, including one of crown ether, cryptether, DNA, cyclodextrin, calixarene, calixpyrrole, calixcarbazole, cucurbitalurea, and columnar aromatics, and N is a metal fluoride, including one of LiF, CsF, NaF, RbF, KF, MgF2, PbF2, SnF2, GeF2, BaF2, ZnF2, LaF3, GdF3, CdF2, SrF2, GaF3, and InF3.

2. The perovskite solar cell according to claim 1, characterized in that, The structure of the perovskite light-absorbing layer is ABX3, wherein A is Rb + , Cs + , MA + , or FA + , B is Pb 2+ , Sn 2+ , or Ge 2+ , and X is I - , Br - , or Cl - .

3. The perovskite solar cell according to claim 1 or 2, characterized in that, The transparent conductive substrate layer is FTO glass, ITO glass, ITO / PET, ITO / PEN, or ITO / PI; the hole transport layer is nickel oxide and doped nickel oxide, PTAA, Spiro-OMeTAD, Me-4PACz, 2PACz, MeO-2PACz, or P3HT; the electron transport layer is fullerene or its derivative; the interface buffer layer is copper bath, tin oxide, zinc oxide, yttrium oxide, cerium oxide, tungsten oxide, titanium oxide, or niobium oxide; the electrode layer is Cu, Ag, Au, Mo, Ni, Sb, Bi, ITO, IZO, AZO, IWO, or ICO.

4. The perovskite solar cell according to claim 1, characterized in that, The surface passivation layer has a thickness of 0.1~80nm; the perovskite light-absorbing layer has a thickness of 100~2000nm; the electron transport layer has a thickness of 1~100nm; the interface buffer layer has a thickness of 1~100nm; and the electrode layer has a thickness of 10~10000nm.

5. A method for preparing a perovskite solar cell according to any one of claims 1 to 4, characterized in that, Includes the following steps: S1. Deposit a hole transport layer on a transparent conductive substrate; S2. Perovskite powder is dissolved in an organic solvent, stirred and clarified to form a perovskite precursor solution. The perovskite precursor solution is coated or printed on the hole transport layer, and after heat treatment, a perovskite light-absorbing layer is obtained. S3. The supramolecular metal complex is dissolved in an organic solvent, stirred and clarified to obtain a supramolecular metal complex solution. The supramolecular metal complex solution is coated on the surface of the perovskite light-absorbing layer, and a surface passivation layer is obtained after heat treatment. S4. An electron transport layer, an interface buffer layer, and an electrode layer are sequentially deposited on the surface passivation layer to obtain a perovskite solar cell.

6. The preparation method according to claim 5, characterized in that, The organic solvent used to prepare the supramolecular metal complex solution is one or more of isopropanol, chlorobenzene, ethyl acetate, butanol, chloroform, benzene, isobutanol, sec-butanol, dichlorobenzene, dimethylbenzene, toluene, acetonitrile, dichloroethane, anisole, and butyl acetate, mixed in any proportion; the organic solvent used to prepare the perovskite precursor solution is one or more of N,N-dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone, 1,3-methyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone, 1,3-dimethyl-2-imidazolinone, 2-methoxyethanol, and acetonitrile, mixed in any proportion.

7. The preparation method according to claim 5, characterized in that, The concentration of the supramolecular metal complex solution is 0.001–100 mg / mL; the concentration of the perovskite precursor solution is 0.1–3 mol / L.

8. The preparation method according to claim 5, 6, or 7, characterized in that, The preparation process of the supramolecular metal complex is as follows: the supramolecular material and the metal fluoride are mixed in tetrahydrofuran and stirred continuously. After the reaction is completed, the mixture is filtered, and the filtrate is concentrated under reduced pressure until dry to obtain a crude product. The crude product is recrystallized multiple times to obtain the supramolecular metal complex.

9. The preparation method according to claim 5, characterized in that, The heat treatment temperature of the surface passivation layer is 30–200℃, and the time is 1–60 min; the heat treatment temperature of the perovskite light-absorbing layer is 30–300℃, and the time is 5–120 min.

10. The preparation method according to claim 5, characterized in that, The electron transport layer is deposited by vapor deposition; the interface buffer layer is deposited by coating, printing, vapor deposition, sputtering, reactive plasma deposition, chemical vapor deposition, coating or printing; the electrode layer is deposited by vapor deposition, sputtering, chemical vapor deposition, coating or printing.

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