Passivation material for perovskite thin film, perovskite solar cell and preparation method

Abstract

The invention discloses a passivation material for a perovskite thin film, a perovskite solar cell and a preparation method, and relates to the technical field of perovskite cells. Comprising a molecule with the following general formula: [R-Ph-R]. 2HI, and an R group is selected from amidino. According to the present invention, the amidino-substituted arylene chain structure is adopted as the core functional component, such that compared with the conventional ammonium ligand, the amidino-substituted arylene chain structure has significantly enhanced chemical stability and deprotonation resistance, further has strong surface binding ability and multi-tooth chelation, can efficiently inhibit non-radiative recombination, can improve the open-circuit voltage and the fill factor, and can improve the anti-radiation performance and the anti-deprotonation performance. The film has excellent thermal stability, is suitable for a commercialized component packaging environment, can be compatible with various processing technologies, and is easy to be integrated to an existing production line.

Description

Technical Field

[0001] This invention relates to the field of perovskite battery technology, and more specifically, to a passivation material for perovskite thin films, a perovskite solar cell, and a method for its fabrication. Background Technology

[0002] Significant progress has been made in the field of perovskite solar cells (PSCs) in the past two years. Through the application of surface passivation technology, the steady-state power conversion efficiency (PCE) of these cells has exceeded 26%. However, the current efficiency is still below the Shockley-Quisser theoretical limit, mainly due to the inherent defects commonly found in perovskite films prepared by solution methods. These defects include, but are not limited to, vacancy defects, interstitial atoms, impurity phases, uncoordinated ions, and dangling bonds, which are not only present in the bulk material but also widely distributed at interfaces. These defects can form trapped states, inducing nonradiative recombination processes, and may also become ion migration channels, ultimately leading to recombination losses of photogenerated carriers and degradation of device performance.

[0003] Defect passivation strategies, which reduce the density of defects in the perovskite bulk phase and grain boundaries, and decrease interface trap states, have proven to be a key approach for achieving high conversion efficiency and long-term operational stability in perovskite solar cells. However, existing passivation materials still suffer from insufficient defect repair efficiency, and their performance needs further improvement.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a passivation material for perovskite thin films, a perovskite solar cell, and a method for its preparation.

[0006] This invention is implemented as follows: In a first aspect, the present invention provides a passivation material for perovskite thin films, comprising a molecule having the following structural formula: [R-Ph-R]·2HI; wherein the R group is selected from amidine.

[0007] By selecting the passivation material with the above structure, it has stronger surface bonding ability and multi-tooth chelation effect, which can effectively suppress non-radiative recombination, improve open circuit voltage and fill factor, and has excellent thermal stability.

[0008] In an optional implementation, the passivating material has the following structural formula: , and At least one of them.

[0009] By selecting the passivation material with the above structure, the amidine group [C(NH2)2] is... +Compared to traditional ammonium-based passivation materials, it is more difficult for deprotonation reactions to occur, and it can maintain structural integrity under long-term light exposure and high-temperature operating conditions, effectively avoiding the regeneration of surface vacancies caused by ligand decomposition, thereby significantly improving the long-term operational stability of the device.

[0010] In an optional embodiment, the coating concentration of the passivation material is 0.8~1.2 mg / mL. By controlling the above concentration, a uniform, dense, and pinhole-free passivation layer film can be formed, improving defect passivation efficiency, while adapting to industrial process windows and enhancing the repeatability and scalability of device production.

[0011] Secondly, the present invention provides a method for preparing a passivating material as described in any of the foregoing embodiments, comprising reacting phthalonitrile with methanol under acidic conditions to undergo an imidization reaction to generate phthalimide dihydrochloride in situ; subjecting the phthalimide dihydrochloride to ammonolysis under the action of an ammonia source to generate phthalimidine dihydrochloride; and subjecting the phthalimidine dihydrochloride to an anion exchange reaction with potassium iodide in a hot solvent system, wherein the obtained reactants are purified to obtain the passivating material.

[0012] Phthalonil includes any one of ortho-phthalonitrile, terephthalonitrile, or iso-phthalonitrile.

[0013] In an optional embodiment, the imino esterification reaction process includes: mixing phthalonitrile and methanol to obtain a first mixture, adding hydrochloric acid or a hydrochloric acid reaction precursor to the first mixture to carry out the reaction, and controlling the reaction temperature to be <5°C; the hydrochloric acid reaction precursor is acetyl chloride.

[0014] And / or, the ammonolysis process includes: dissolving phenyl diimide dihydrochloride in methanol to obtain a second mixture, adding an ammonia source to the second mixture, mixing, cooling for 5-15 minutes, and then heating to react.

[0015] And / or, the anion exchange reaction process includes: mixing benzodiazepine dihydrochloride with methanol to obtain a third mixture, adding potassium iodide solution to the third mixture, then heating under reflux to react, filtering while hot after the reaction is completed, and concentrating the filtrate under reduced pressure.

[0016] Thirdly, the present invention provides a perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a perovskite absorber layer, an electron transport layer and a conductive electrode layer stacked sequentially, wherein at least one stacked surface of the perovskite absorber layer is provided with a passivation layer.

[0017] The passivation layer material includes any of the passivation materials described in the foregoing embodiments. By employing the aforementioned passivation material to prepare perovskite solar cells, the overall electrochemical performance of perovskite solar cells is improved.

[0018] In an optional implementation, the thickness of the passivation layer is 1~2 nm.

[0019] Fourthly, the present invention provides a method for fabricating a perovskite solar cell as described in the foregoing embodiments, comprising sequentially coating a hole transport layer, a perovskite absorber layer, an electron transport layer, and a conductive electrode layer on the surface of a transparent conductive substrate.

[0020] Furthermore, at least one layer of the perovskite absorber layer is coated with a passivation layer.

[0021] In an optional embodiment, the preparation of the passivation layer includes dissolving the passivation material in an alcohol solvent to obtain a passivation layer solution, applying the passivation layer solution to the surface of the perovskite absorber layer, and then performing an annealing treatment.

[0022] In optional implementations, at least one of the following features is included: 1) Alcohol solvents include at least one of hexafluoroisopropanol, isopropanol and ethanol.

[0023] 2) In the passivation layer solution, the concentration of the passivation material is 0.8~1.2 mg / mL.

[0024] 3) The annealing temperature of the passivation layer solution is 90~110℃, and the annealing time is 8~12min.

[0025] By controlling the preparation process of the passivation layer within the above-mentioned range, the defect repair effect of the passivation material can be maximized, while avoiding any impact on the performance of the perovskite absorber layer.

[0026] The present invention has the following beneficial effects: This invention provides a passivation material for perovskite thin films, a perovskite solar cell, and a preparation method thereof. By using an amidine-substituted aryl chain structure as the core functional component, it exhibits significantly enhanced chemical stability and deprotonation resistance compared to conventional ammonium ligands. It also possesses stronger surface binding ability and multidentate chelation effect, which can efficiently suppress nonradiative recombination, improve open-circuit voltage and fill factor, and demonstrate excellent thermal stability. It is suitable for commercial component packaging environments, compatible with various processing technologies, and easy to integrate into existing production lines. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1This is a schematic diagram of the structure of a perovskite solar cell provided in an embodiment of the present invention; Figure 2 The graph shows the thermal stability test results of the perovskite solar cells provided in Embodiment 1 and Comparative Example 1 of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0030] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0031] In a first aspect, the present invention provides a passivation material for perovskite thin films, comprising a molecule having the following structural formula: [R-Ph-R]·2HI; wherein the R group is selected from amidine.

[0032] Existing passivation materials for perovskite absorber layers are mainly low-dimensional perovskites, aromatic amines, and ammonium ligands. Although these can improve the stable power conversion efficiency (PCE) of perovskite solar cells, the efficiency of perovskite solar cells is still below the Shockley-Quiser theoretical limit.

[0033] This invention uses an amidoyl-substituted aryl chain as the core functional component, exhibiting significantly better technical effects than traditional ammonium-based passivation materials in terms of perovskite surface defect passivation and interface stability improvement.

[0034] By employing an amidoyl-substituted aryl chain as the core functional component, it exhibits significantly enhanced chemical stability and deprotonation resistance compared to conventional ammonium ligands. It also possesses stronger surface binding capacity and multidentate chelation, effectively suppressing nonradiative recombination, improving open-circuit voltage and fill factor, and demonstrating excellent thermal stability. It is suitable for commercial component packaging environments, compatible with various processing technologies, and easy to integrate into existing production lines.

[0035] In an optional embodiment, the passivating material has the following structural formula: , and At least one of them.

[0036] It should be noted that the above three amidine-substituted aromatic diamine iodides are formed by replacing the carbon group of propan-1,3-diammonium iodide (PDAI2) passivating material with a phenyl group, thereby creating ammonium-based passivating materials such as p-phenylenediamine iodide (PhDADI), m-phenylenediamine iodide (mPhDADI), and o-phenylenediamine iodide (oPhDADI). The chemical formula of p-phenylenediamine iodide (PhDADI) is... The chemical formula of m-phenylenediamine iodine (mPhDADI) is: The chemical formula of o-phenylenediamine iodine (oPhDADI) is: .

[0037] Then, the ammonium groups of the above three ammonium-based passivating materials (p-phenylenediamine iodine, m-phenylenediamine iodine, and o-phenylenediamine iodine) were substituted with amidine groups to obtain the passivating material provided by this invention. For ease of subsequent explanation, the compounds provided by this invention... Hereinafter referred to as PhDII2, Hereinafter referred to as mPhDII2, Hereinafter referred to as oPhDII2.

[0038] The inventors discovered that conventional ammonium ligands (such as PDAI2, PEAI, etc.) are prone to deprotonation reactions under photothermal stress, generating volatile amines and halogen vacancies, leading to passivation material failure. This invention selects compounds with the above three structures as passivation materials for perovskite films, among which the amidine cation [C(NH2)2]... + It possesses a planar conjugated structure and resonance stabilization effect, and its N–H bond dissociation energy (E) a The chemical stability of the passivation material is higher and more difficult to undergo deprotonation. Therefore, this invention creatively introduces an amidine group into the passivation material, which can maintain structural integrity under long-term light exposure and high-temperature operating conditions, effectively avoiding the regeneration of surface vacancies caused by ligand decomposition, thereby significantly improving the long-term operational stability of the device. Compared with existing ammonium-based ligand passivation materials, the amidine-substituted aromatic diamine iodide salt provided by this invention has significantly enhanced chemical stability and deprotonation resistance.

[0039] Furthermore, the amidine-substituted aromatic diamine iodide salt provided by this invention not only retains the benzene ring skeleton and the uncoordinated Pb on the perovskite surface, but also... 2+ The strong π-σ interaction between the perovskite and benzene rings also enables a tetradentate hydrogen bond coordination mode (which can form four hydrogen bonds simultaneously) through the amidine functional group, while traditional ammonium-based passivation materials can only form three hydrogen bonds. This results in stronger surface bonding and multidentate chelation compared to traditional ammonium-based passivation materials. Furthermore, the rigid structure of the benzene ring helps guide ordered termination on the perovskite surface, further reducing interfacial disorder. This multi-layered synergistic effect significantly enhances the bonding energy between the passivation layer and the perovskite surface, improving passivation coverage and durability.

[0040] In an optional embodiment, the coating concentration of the passivating material is 0.8~1.2 mg / mL.

[0041] By controlling the coating concentration of the passivation material within the above range, a uniform, dense, and pinhole-free passivation layer film can be formed, improving defect passivation efficiency, suppressing non-radiative recombination, and avoiding swelling or erosion of the underlying perovskite film. This adapts to industrial process windows and enhances the repeatability and scalability of device production.

[0042] When the coating concentration of the passivation material is below 0.8 mg / mL, the adsorption density of the active functional group (mididine group) on the perovskite film surface is insufficient, and Pb cannot be sufficiently passivated. 2+ Empty space and I - Major defects include vacancies; when the coating concentration of the passivation material exceeds 1.2 mg / mL, it may lead to excessively thick accumulation of passivation material molecules, introducing additional charge transport barriers. The coating concentration range of the passivation material provided by this invention can achieve an optimal balance between passivation coverage and interfacial charge transport performance, significantly improving open-circuit voltage (Voc) and fill factor (FF).

[0043] Secondly, the present invention provides a method for preparing a passivating material as described in any of the foregoing embodiments, comprising reacting phthalonitrile with methanol under acidic conditions to undergo an imidization reaction to generate phthalimide dihydrochloride in situ; subjecting the phthalimide dihydrochloride to ammonolysis under the action of an ammonia source to generate phthalimidine dihydrochloride; and subjecting the phthalimidine dihydrochloride to an anion exchange reaction with potassium iodide in a hot solvent system, wherein the obtained reactants are purified to obtain the passivating material.

[0044] Phthalonil includes any one of phthalonitrile, terephthalonitrile, or isophthalonitrile. Therefore, it is understandable that when the reactant is phthalonitrile, all intermediates in the reaction process are ortho-substituted, such as phthalimide dihydrochloride and phthalimidine dihydrochloride, and the final passivating material obtained from the reaction is also ortho-substituted, such as oPhDII2.

[0045] When the reactant is terephthalonitrile, all intermediates in the reaction process are para-substituted, such as terephthalimide dihydrochloride and terephthalamide dihydrochloride. The passivating material obtained by the final reaction is also para-substituted, such as PhDII2.

[0046] When the reactant is isophthalonitrile, all intermediates in the reaction process are meta-substituted, such as isophthalimide dihydrochloride and isophthalamide dihydrochloride. The passivation material obtained by the final reaction is also meta-substituted, such as mPhDII2.

[0047] In an optional embodiment, the imino esterification reaction process includes: mixing phthalonitrile and methanol to obtain a first mixture, adding hydrochloric acid or a hydrochloric acid reaction precursor to the first mixture to carry out the reaction, and controlling the reaction temperature to be <5°C.

[0048] When hydrochloric acid is added to the first mixture, the molar ratio of phthalonitrile, methanol and hydrochloric acid is 1:1.8~2.2:1.8~2.2.

[0049] When the first mixture contains a hydrochloric acid reaction precursor, the molar ratio of phthalonitrile, methanol and hydrochloric acid reaction precursor is 1:2.9~6:2.9~3.2.

[0050] The hydrochloric acid precursor is acetyl chloride, or other raw materials that can generate HCl in the reaction system of phthalonitrile and methanol.

[0051] In an optional embodiment, to avoid side reactions, hydrochloric acid or hydrochloric acid reaction precursor is added to the first mixture dropwise, and the reaction temperature is controlled to be <5°C. For example, the reaction vessel can be placed in an ice bath to carry out the above process.

[0052] In an optional embodiment, after the hydrochloric acid or hydrochloric acid reaction precursor has been added, the ice bath is removed, and the reaction is stirred at room temperature for 12-24 hours.

[0053] In an optional embodiment, to ensure the purity and yield of the passivation material, the reactants obtained from the imino esterification reaction need to be post-processed. For example, the reactants obtained from the imino esterification reaction can be vacuum filtered, the white solid washed with a large amount of anhydrous diethyl ether, and then dried in a vacuum drying oven at 40-50°C for 6 hours to obtain a white powdery intermediate, phenylenediamine dihydrochloride.

[0054] In an optional embodiment, the ammonolysis reaction process includes: dissolving phenyl diimide dihydrochloride in methanol to obtain a second mixture, adding an ammonia source to the second mixture, mixing, cooling for 5-15 minutes, and then heating to react.

[0055] In an optional embodiment, the ammonia source is liquid ammonia. The molar ratio of phenylenediamine dihydrochloride to liquid ammonia is 1:0.8~1.2.

[0056] In optional embodiments, some intermediates, such as isophthalimide dihydrochloride, have relatively poor solubility. In such cases, a co-solvent such as anhydrous 1,4-dioxane can be added to aid dissolution. If isophthalimide dihydrochloride is soluble in methanol, a co-solvent is not necessary.

[0057] In an optional embodiment, the reaction temperature of phthalimide dihydrochloride and the ammonia source is 55~65°C, and the reaction time is 24~48h.

[0058] In an optional embodiment, the reaction temperature of terephthalimide dihydrochloride and the ammonia source is 0~25°C, and the reaction time is 24~48h.

[0059] In an optional embodiment, the reaction temperature of isophthalimide dihydrochloride and the ammonia source is 35~40℃, and the reaction time is 48~72h.

[0060] In an optional embodiment, to ensure the purity and yield of the passivation material, the reactants obtained from the ammonolysis reaction need to be post-treated. The post-treatment includes cooling the reactants to room temperature, then rotary evaporating them at 35-45°C to remove most of the solvent and ammonia, and washing the solid with cold anhydrous ethanol to obtain benzodiazepine dihydrochloride.

[0061] In an optional embodiment, the anion exchange reaction process includes: mixing benzodiazepine dihydrochloride with methanol to obtain a third mixture, adding potassium iodide solution to the third mixture, and immediately generating a white potassium chloride precipitate upon the addition of potassium iodide solution to the third mixture, then heating and refluxing the reaction, filtering while hot after the reaction is completed to remove the potassium chloride precipitate, then concentrating the filtrate under reduced pressure, and placing the concentrated solution at 0~5℃ for crystallization for 10~15h.

[0062] In an optional embodiment, the molar ratio of benzodiazepine dihydrochloride to potassium iodide is 1:1.8~2.2.

[0063] In an optional embodiment, purification includes washing the crystals obtained from crystallization with ice-cold methanol or an ethanol-ether mixture.

[0064] In an optional embodiment, to further improve the purity of the passivation material, a second washing with a hot water-methanol mixed solvent can be performed to further purify the product obtained from the reaction.

[0065] Thirdly, the present invention provides a perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a perovskite absorber layer, an electron transport layer and a conductive electrode layer stacked sequentially, wherein at least one stacked surface of the perovskite absorber layer is provided with a passivation layer.

[0066] It should be noted that the stacked surfaces of the perovskite absorber layer refer to the surfaces in contact with the hole transport layer and the surfaces in contact with the electron transport layer. By setting passivation layers between the stacked interfaces of the perovskite absorber layer, defects on the surface of the perovskite absorber layer can be better repaired, while improving the overall performance of the perovskite solar cell.

[0067] That is, the perovskite solar cell provided by this invention can have any one of the following three structures: 1) A perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a perovskite absorber layer, a passivation layer, an electron transport layer and a conductive electrode layer stacked sequentially.

[0068] 2) A perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a passivation layer, a perovskite absorber layer, an electron transport layer, and a conductive electrode layer stacked sequentially.

[0069] 3) A perovskite solar cell, comprising a transparent conductive substrate, a hole transport layer, a passivation layer, a perovskite absorber layer, a passivation layer, an electron transport layer, and a conductive electrode layer stacked sequentially.

[0070] The passivation layer material includes any of the passivation materials described in the foregoing embodiments, in order to improve the overall electrochemical performance of the perovskite solar cell.

[0071] In an optional embodiment, the thickness of the passivation layer is 1~2 nm. By controlling the thickness of the passivation layer within the above range, Pb can be sufficiently passivated. 2+ Empty space and I - The main defects include vacancies, while avoiding excessively thick accumulation of passivation material molecules, which would introduce additional charge transport barriers.

[0072] In an alternative implementation, the layers of the perovskite solar cell can be constructed using existing materials.

[0073] For example, the materials for transparent conductive substrates include, but are not limited to, indium tin oxide (ITO) and fluorine-doped tin oxide (FTO). Other existing materials suitable for perovskite solar cells can also be used as transparent conductive substrate materials.

[0074] The hole transport layer material includes at least one of Me-4PACZ, PFN-Br, MeO-4PACZ, Me-2PACZ, and MeO-2PACZ. Me-4PACZ is a methyl-modified carbazole-based organic semiconductor material, and PFN-Br is a conjugated polyelectrolyte material; both are common hole transport layer materials. Therefore, the passivation material provided by this invention is applicable to existing perovskite solar cell materials and has a wide range of applications.

[0075] Materials for the perovskite absorber layer include, but are not limited to, Cs. 0.05 (FA 0.98 MA 0.02 ) 0.95 Pb(I 0.98 B r0.02 3. Cs 0.05 FA0.95 PbI3 and Cs 0.05 MA 0.05 FA 0.9 Any of the PbI3 materials, such as the perovskite absorber layer, can also be other existing materials that can be applied to perovskite solar cells.

[0076] The materials for the electron transport layer include, but are not limited to, at least one of C60, SnO2, PCBM and BCP. For example, other existing materials that can be used in perovskite solar cells can also be used for the electron transport layer.

[0077] The material of the conductive electrode layer includes, but is not limited to, at least one of copper, silver and gold. For example, the material of the conductive electrode layer can also be other existing materials that can be applied to perovskite solar cells.

[0078] Furthermore, the thickness parameters of each layer of the perovskite solar cell can be set according to actual needs. For example, the thickness of the transparent conductive substrate can be 2~5 mm. The thickness of the perovskite absorber layer can be 500~800 nm. The thickness of the electron transport layer can be 20~80 nm. The thickness of the conductive electrode layer can be 80~150 nm.

[0079] It should be noted that the thicknesses of the aforementioned transparent conductive substrate, perovskite absorber layer, electron transport layer, and conductive electrode layer are merely selectable thickness ranges provided in the embodiments of the present invention and should not be construed as limitations on the perovskite solar cells provided by the present invention. The core of the present invention lies in providing a novel passivation layer material, which has a wide range of applications and can be used in various existing perovskite solar cell structures.

[0080] Fourthly, the present invention provides a method for fabricating a perovskite solar cell as described in the foregoing embodiments, comprising sequentially coating a hole transport layer, a perovskite absorber layer, an electron transport layer, and a conductive electrode layer on the surface of a transparent conductive substrate.

[0081] Furthermore, at least one layer of the perovskite absorber layer is coated with a passivation layer.

[0082] In an optional embodiment, the preparation of the passivation layer includes dissolving the passivation material in an alcohol solvent to obtain a passivation layer solution, applying the passivation layer solution to the surface of the perovskite absorber layer, and then performing an annealing treatment.

[0083] In optional embodiments, alcohol solvents are not only good solvents but also functional processing media. While achieving efficient dissolution, they protect the perovskite bulk structure and promote the orderly arrangement of passivation molecules at the interface, which is the key process basis for achieving high-performance passivation.

[0084] The alcohol solvent includes at least one of hexafluoroisopropanol, ethanol and isopropanol, preferably hexafluoroisopropanol.

[0085] Because the passivation material used in this invention is a strongly polar organic cationic compound, there are strong hydrogen bonds and electrostatic interactions between molecules, making it difficult to dissolve effectively with conventional alcohols or nonpolar solvents. However, this invention uses hexafluoroisopropanol (HFIP) as the solvent for dissolving amidine-substituted aromatic diamine iodides. HFIP has strong hydrogen bond donor capability (high α value) and high polarity, which can effectively disrupt intermolecular forces, allowing these amidine salts to fully dissociate and stably disperse, forming a uniform and transparent passivation solution, ensuring the uniformity of subsequent film formation.

[0086] Furthermore, most organic solvents (such as DMF, DMSO, NMP, ethanol, etc.) can partially dissolve or swell perovskite films, leading to grain recrystallization, surface roughness, or the formation of new defects. The HFIP selected in this invention is a weakly nucleophilic, low-reactivity fluorinated alcohol. Its strong electron-withdrawing effect of fluorine atoms reduces the nucleophilicity and proton transfer ability of the hydroxyl groups, thus affecting the underlying Cs... 0.05 (FA 0.98 MA 0.02 ) 0.95 Pb(I 0.98 B r0.02 Perovskite materials of type 3 have almost no corrosive effect and can achieve non-destructive surface treatment.

[0087] Furthermore, HFIP has a moderate boiling point (approximately 58~60℃), allowing it to evaporate rapidly at lower temperatures (such as 100℃) after spin coating, avoiding side reactions caused by prolonged high-temperature processing. At the same time, HFIP has low surface tension, which helps the solution spread evenly on the perovskite surface, forming a dense, ultra-thin, and continuous passivation layer, thus improving interface coverage.

[0088] Furthermore, HFIP can enhance molecular orientation and interfacial interactions. The strongly polar environment of HFIP facilitates the adsorption of amidine cations in optimal conformation at perovskite surface defect sites (such as uncoordinated Pb). 2+ Or I - (Vacant), promoting its firm anchoring through NH…I hydrogen bonds and electrostatic interactions, thereby improving passivation efficiency.

[0089] In the passivation layer solution, the concentration of the passivation material is 0.8–1.2 mg / mL. Ensuring sufficient surface passivation while avoiding the negative effects of over-deposition, achieving excellent defect repair capabilities, efficient charge extraction performance, and superior thermal stability, is one of the key process parameters for obtaining high-efficiency, long-life perovskite solar cells.

[0090] The annealing temperature of the passivation layer solution is 90~110℃, and the annealing time is 8~12min. Controlling the annealing parameters within the above range can ensure the bonding between the passivation layer material and the perovskite absorber layer, while avoiding side reactions.

[0091] In an optional implementation, the materials for each layer of the perovskite solar cell can be prepared using conventional processes.

[0092] For example, the preparation of a hole transport layer includes coating a hole transport paste onto the surface of a transparent conductive substrate and then annealing it.

[0093] The cavitation transport slurry comprises a Me-4PACZ solution and a PFN-Br solution in a volume ratio of 8.5:1 to 9.5:1, with the Me-4PACZ solution having a concentration of 0.1 to 0.3 mg / mL and the PFN-Br solution having a concentration of 0.1 to 0.3 mg / mL.

[0094] The annealing temperature for the cavitation transport slurry is 90~110℃, and the annealing time is 8~12min.

[0095] The preparation of the perovskite absorber layer involves coating a perovskite slurry onto the surface of the hole transport layer and then annealing it.

[0096] The preparation of the perovskite slurry includes dissolving the material of the perovskite absorber layer with an organic solvent; the organic solvent includes at least one of N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), acetonitrile, and dimethyl sulfoxide.

[0097] The concentration of the perovskite absorber layer material in the perovskite slurry is 1~1.5M.

[0098] The annealing temperature of the perovskite slurry is 120~140℃, and the annealing time is 18~22min.

[0099] The electron transport layer is prepared by using thermal evaporation to prepare a C60 layer and / or by using atomic layer deposition to prepare a SnO2 layer.

[0100] The fabrication of the conductive electrode layer involves depositing the material of the conductive electrode layer using a thermal evaporation method.

[0101] It should be noted that the methods for preparing the above-described transparent conductive substrate, hole transport layer, perovskite absorber layer, electron transport layer, and conductive electrode layer are merely examples of embodiments of the present invention and should not be construed as limiting the present invention. Any passivation layer prepared using the passivation material provided in the embodiments of the present invention, when applied to various existing perovskite solar cell structures, falls within the scope of protection of the present invention.

[0102] Example 1 This embodiment provides a passivation material for perovskite thin films, specifically PhDII2, with the following structure: .

[0103] This embodiment also provides a method for preparing the above-mentioned passivation material for perovskite thin films, including the following steps: S01, Imino esterification reaction Terephthalonitrile reacts with methanol under acidic conditions to undergo an imidization reaction, generating terephthalic acid ester dihydrochloride in situ. The reaction equation is as follows: NC-C6H4-CN (para position) + 2 CH3OH + 2 HCl (g) → [CH3O-C(=NH)-C6H4-C(=NH)-OCH3]·2HCl↓.

[0104] 10.0 g of terephthalonitrile was suspended in 19 mL of anhydrous methanol and cooled to 0 °C in an ice bath to obtain the first mixture. 16.7 mL of acetyl chloride and 80 mL of anhydrous dichloromethane were mixed in a dropping funnel and then slowly added dropwise to the first mixture to react. The reaction temperature was controlled to be <5 °C and the reaction was completed in about 1 to 1.5 h. The ice bath was then removed and the mixture was stirred at room temperature for 18 to 24 h to obtain the reactants for the imino esterification reaction.

[0105] To ensure the purity and yield of the passivation material, the reactants obtained from the imino esterification reaction need to be post-processed. Specifically, the reactants obtained from the imino esterification reaction can be vacuum filtered using a Buchner funnel to collect the white precipitate. The white solid is then washed with a large amount of anhydrous diethyl ether to remove residual methanol and byproducts. The solid is then dried in a vacuum drying oven at 40-50°C for 6 hours to obtain a white powdery intermediate, terephthalic acid dihydrochloride.

[0106] SO2, ammonolysis reaction The terephthalimine dihydrochloride obtained in step S01 was subjected to ammonolysis under the action of an ammonia source to generate terephthalamide dihydrochloride. The reaction equation is as follows: [CH3O-C(=NH)-C6H4-C(=NH)-OCH3]·2HCl + 2 NH3→ [H2N-C(=NH)-C6H4-C(=NH)-NH2]·2HCl + 2 CH3OH Take 15.0 g of terephthalic acid dihydrochloride obtained from step S01, then add 200 mL of 7 N ammonia-methanol solution, then cool the reaction system in an ice-water bath at 0 °C, then stopper the bottle tightly, and stir the reaction at 0 °C to room temperature.

[0107] To ensure the purity and yield of the passivation material, the reactants obtained from the ammonolysis reaction need to be post-treated. The post-treatment includes cooling the reactants to room temperature, then rotary evaporating them at 40°C to remove most of the solvent and ammonia, and washing the solid with cold anhydrous ethanol to obtain terephthalamide dihydrochloride.

[0108] SO3, anion exchange reaction The terephthalamide dihydrochloride obtained in step S02 was subjected to anion exchange reaction with potassium iodide in a hot solvent system. The resulting reactants were purified to obtain the passivating material (PhDII2). The reaction equation is as follows: [H2N-C(=NH)-C6H4-C(=NH)-NH2]·2HCl + 2 KI → [H2N-C(=NH)-C6H4-C(=NH)-NH2]·I2+ 2 KCl↓ 10.0 g of terephthalamide dihydrochloride obtained in step S02 was mixed with 150 mL of hot methanol (60 °C) to obtain a third mixture; 15.8 g of potassium iodide was dissolved in 30 mL of deionized water to obtain a potassium iodide solution; under stirring conditions, the potassium iodide solution was slowly added to the third mixture, and a large amount of white potassium chloride precipitate was immediately generated. The reaction system was then heated to reflux at 65 °C for 15-30 min. After the reaction was completed, the mixture was filtered while hot to remove the potassium chloride precipitate. The filtrate was then concentrated under reduced pressure, and the concentrate was placed at 4 °C overnight for crystallization.

[0109] The crystals obtained from crystallization are washed with ice-cold methanol or an ethanol-ether mixture. To further improve the purity of the passivation material, a second washing with a hot water-methanol mixture can be used to further purify the product obtained from the reaction.

[0110] Please refer to Figure 1 This embodiment also provides a perovskite solar cell 100, which includes a transparent conductive substrate 106, a hole transport layer 105, a passivation layer 103, a perovskite absorption layer 104, an electron transport layer 102 and a conductive electrode layer 101 stacked sequentially from bottom to top.

[0111] The transparent conductive substrate 106 is 5×5 cm. 2 The hole transport layer 105 is a mixture of Me-4PACZ and PFN-Br; the passivation layer 103 is made of PhDII2 provided in this embodiment; the perovskite absorber layer 104 is Cs 0.05 (FA 0.98 MA 0.02 ) 0.95 Pb(I 0.98 B r0.023; the electron transport layer 102 is a composite structure of C60 and SnO2; the conductive electrode layer 101 is a copper electrode.

[0112] This embodiment also provides a method for preparing the above-mentioned perovskite solar cell, including the following steps: S01. Indium tin oxide (ITO) material with a thickness of 2.2 mm is used as a transparent conductive substrate.

[0113] S02. Preparation of hole transport layer: Mix 0.2 mg / mL Me-4PACZ and 0.2 mg / mL PFN-Br at a volume ratio of 9:1 and stir overnight to obtain hole transport slurry.

[0114] Hole transport slurry was coated onto an ITO substrate using a spin coater, and then annealed at 100°C for 10 min to obtain a hole transport layer.

[0115] S03. Preparation of the perovskite absorber layer: DMF and NMP are mixed in a volume ratio of 6:1 to obtain a mixed solvent, and Cs is dissolved in this mixed solvent. 0.05 (FA 0.98 MA 0.02 ) 0.95 Pb(I 0.98 B r0.02 3. Cs in perovskite slurry 0.05 (FA 0.98 MA 0.02 ) 0.95 Pb(I 0.98 B r0.02 The concentration of 3 was 1.2M, and the mixture was stirred overnight to obtain a perovskite slurry.

[0116] The perovskite slurry was coated onto the surface of the hole transport layer in step S02 using a spin coater, and then annealed at 130°C for 20 min to obtain a perovskite absorber layer with a thickness of 600 nm.

[0117] S04. Preparation of passivation layer: Dissolve PhDII2 provided in this example in hexafluoroisopropanol and stir for 1 hour to prepare a passivation layer solution with a concentration of 1.0 mg / mL.

[0118] The completely dissolved passivation layer solution was coated onto the surface of the perovskite absorber layer obtained in step S03 using a spin coater, and then annealed at 100°C for 10 min to obtain the passivation layer.

[0119] S05. Preparation of electron transport layer: A C60 layer with a total thickness of 30 nm is prepared on the surface of the passivation layer in step S04 by thermal evaporation; then a SnO2 layer with a thickness of 20 nm is prepared by atomic layer deposition.

[0120] S06. Fabrication of the conductive electrode layer: On the surface of the electron transport layer from step S05, a copper electrode is deposited using a thermal evaporation apparatus. The vacuum level of the thermal evaporation chamber is 10. -5 Pa, metal evaporation rate of 5 nm / min, copper electrode thickness of 110 nm.

[0121] Example 2 This embodiment provides a passivation material for perovskite thin films, specifically mPhDII2, with the following structural formula: .

[0122] This embodiment also provides a method for preparing the above-mentioned passivation material, including the following steps: S01, Imino esterification reaction isophthalonitrile reacts with methanol under acidic conditions to undergo an imidization reaction, producing isophthalic acid ester dihydrochloride in situ. The reaction equation is as follows: NC-C6H4-CN (meta) + 2 CH3OH + 2 HCl (g) → [CH3O-C(=NH)-C6H4-C(=NH)-OCH3]·2HCl↓.

[0123] 10.0 g of isophthalonitrile was suspended in 100 mL of anhydrous methanol and cooled in an ice bath to -5 to 0 °C to obtain the first mixture. 16.7 mL of acetyl chloride and 80 mL of anhydrous dichloromethane were mixed in a dropping funnel and then slowly added dropwise to the first mixture to react. The reaction temperature was controlled to be <5 °C and the reaction was completed in about 1 to 1.5 h. The ice bath was then removed and the mixture was stirred at room temperature for 18 to 24 h to obtain the reactants for the imino esterification reaction.

[0124] To ensure the purity and yield of the passivation material, the reactants obtained from the imino esterification reaction need to be post-processed. Specifically, the reactants obtained from the imino esterification reaction can be vacuum filtered using a Buchner funnel to collect the white precipitate. The white solid is then washed with a large amount of anhydrous diethyl ether to remove residual methanol and byproducts. The solid is then dried in a vacuum drying oven at 40-50°C for 6 hours to obtain a white powdery intermediate, m-phenylenediamine dihydrochloride.

[0125] SO2, ammonolysis reaction The isophthalimide dihydrochloride obtained in step S01 is subjected to ammonolysis under the action of an ammonia source to generate isophthalamide dihydrochloride. The reaction equation is as follows: [CH3O-C(=NH)-C6H4-C(=NH)-OCH3]·2HCl + 2 NH3→ [H2N-C(=NH)-C6H4-C(=NH)-NH2]·2HCl + 2 CH3OH Take 15.0g of the m-phenylenediamine dihydrochloride obtained from step S01, then add 200mL of 7N ammonia-methanol solution, then place the reaction system in a 0℃ ice-water bath to cool for 10min, then stopper the bottle tightly, and stir vigorously at 35~40℃ and reflux condense (cool water is circulated through the condenser) for 48~72h.

[0126] To ensure the purity and yield of the passivation material, the reactants obtained from the ammonolysis reaction need to be post-treated. The post-treatment includes cooling the reactants to room temperature, then rotary evaporating them at 40°C to remove most of the solvent and ammonia, and washing the solid with cold anhydrous ethanol to obtain isophthalamide dihydrochloride.

[0127] SO3, anion exchange reaction The isophthalamide dihydrochloride obtained in step S02 was reacted with potassium iodide in a hot solvent system via anion exchange reaction. The resulting reactants were purified to obtain the passivating material (mPhDII2). The reaction equation is as follows: [H2N-C(=NH)-C6H4-C(=NH)-NH2]·2HCl + 2 KI → [H2N-C(=NH)-C6H4-C(=NH)-NH2]·I2+ 2 KCl↓ 10.0 g of isophthalamide dihydrochloride obtained in step S02 was mixed with 200 mL of hot methanol (65-70 °C) to obtain a third mixture; 15.8 g of potassium iodide was dissolved in 40 mL of deionized water to obtain a potassium iodide solution; under stirring conditions, the potassium iodide solution was slowly added to the third mixture, and a large amount of white potassium chloride precipitate was immediately generated. The reaction system was then heated to reflux at 70 °C for 30 min. After the reaction was completed, the mixture was filtered while hot to remove the potassium chloride precipitate. The filtrate was then concentrated under reduced pressure, and the concentrate was placed at 4 °C overnight for crystallization.

[0128] The crystals obtained from crystallization are washed with ice-cold methanol or an ethanol-ether mixture. To further improve the purity of the passivation material, a second washing with a hot water-methanol mixture can be used to further purify the product obtained from the reaction.

[0129] This embodiment also provides a perovskite solar cell and its preparation method, the only difference from Embodiment 1 is that the material of the passivation layer is mPhDII2 provided in this embodiment.

[0130] Example 3 This embodiment provides a passivation material for perovskite thin films, specifically oPhDII2, with the following structural formula: .

[0131] This embodiment also provides a method for preparing the above-mentioned passivation material, including the following steps: S01, Imino esterification reaction Phthalonil reacts with methanol under acidic conditions to undergo an imidization reaction, producing phthalimide dihydrochloride in situ. The reaction equation is as follows: NC-C6H4-CN (ortho) + 2 CH3OH + 2 HCl (g) → [CH3O-C(=NH)-C6H4-C(=NH)-OCH3]·2HCl↓.

[0132] 5.0 g of phthalonitrile was suspended in 8.1 mL of anhydrous methanol and cooled to 0 °C in an ice bath to obtain the first mixture. 8.6 mL of acetyl chloride and 50 mL of anhydrous dichloromethane were mixed in a constant pressure dropping funnel and then slowly added dropwise to the first mixture to react. The reaction temperature was controlled to be <5 °C and the reaction was completed in about 1 to 1.5 h. The ice bath was then removed and the mixture was stirred at room temperature for 12 to 24 h to obtain the reactants for the imino esterification reaction.

[0133] To ensure the purity and yield of the passivation material, the reactants obtained from the imino esterification reaction need to be post-processed. Specifically, the reactants obtained from the imino esterification reaction can be vacuum filtered using a Buchner funnel to collect the white precipitate. The white solid is then washed with a large amount of anhydrous diethyl ether to remove residual methanol and byproducts. The solid is then dried in a vacuum drying oven at 40–50°C for 4–6 hours to obtain a white powdery intermediate, phthalimino ester dihydrochloride. This product is highly hygroscopic and must be stored in a desiccator in a sealed container.

[0134] SO2, ammonolysis reaction The phthalimide dihydrochloride obtained in step S01 is subjected to ammonolysis under the action of an ammonia source to generate phthalimidine dihydrochloride. The reaction equation is as follows: [CH3O-C(=NH)-C6H4-C(=NH)-OCH3]·2HCl + 2 NH3→ [H2N-C(=NH)-C6H4-C(=NH)-NH2]·2HCl + 2 CH3OH Take 5.0 g of phthalimide dihydrochloride obtained from step S01 and mix it with 50 mL of anhydrous methanol to obtain a second mixture. Carefully transfer the second mixture into a sealed reactor. Slowly introduce liquid ammonia into the reactor through the inlet valve. The liquid ammonia will vaporize, rapidly cool, and generate high pressure. Then close the valve, start stirring, and heat to 60°C for 24–48 h. Due to the vaporization of liquid ammonia and methanol vapor, the pressure will increase significantly, expected to be in the range of 10–20 bar. After the reaction is complete, cool the reactor to room temperature, then slowly and carefully release excess ammonia gas in a fume hood. Open the reactor and transfer the reaction mixture to a round-bottom flask.

[0135] To ensure the purity and yield of the passivation material, the reactants obtained from the ammonolysis reaction need to be post-treated. The post-treatment includes cooling the reactants to room temperature, then rotary evaporating them at 40°C to remove most of the solvent and ammonia, and washing the solid with cold anhydrous ethanol to obtain phthalimidine dihydrochloride.

[0136] SO3, anion exchange reaction The phthalimidine dihydrochloride obtained in step S02 was subjected to an anion exchange reaction with potassium iodide in a hot solvent system. The resulting reactants were purified to obtain the passivating material (oPhDII2). The reaction equation is as follows: [H2N-C(=NH)-C6H4-C(=NH)-NH2]·2HCl + 2 KI → [H2N-C(=NH)-C6H4-C(=NH)-NH2]·I2+ 2 KCl↓ 3.0 g of phthalimidine dihydrochloride obtained in step S02 was mixed with hot methanol (70 °C) to obtain a third mixture; 4.6 g of potassium iodide was dissolved in 10 mL of deionized water to obtain a potassium iodide solution; under stirring conditions, the potassium iodide solution was slowly added to the third mixture, and a large amount of white potassium chloride precipitate was immediately generated. The reaction system was then heated to reflux at 70 °C for 15 min. After the reaction was completed, the mixture was filtered while hot to remove the potassium chloride precipitate. The filtrate was then concentrated under reduced pressure, and the concentrate was placed at 4 °C overnight for crystallization.

[0137] The crystals obtained from crystallization are washed with ice-cold methanol or an ethanol-ether mixture. To further improve the purity of the passivation material, a second washing with a hot water-methanol mixture can be used to further purify the product obtained from the reaction.

[0138] This embodiment also provides a perovskite solar cell and its preparation method, the only difference from Embodiment 1 is that the material of the passivation layer is oPhDII2 provided in this embodiment.

[0139] Comparative Example 1 This comparative example provides a perovskite solar cell and its fabrication method. The only difference from Example 1 is that the passivation layer material is PhDADI, and its structure is... .

[0140] Comparative Example 2 This comparative example provides a perovskite solar cell and its fabrication method. The only difference from Example 1 is that the passivation layer material is mPhDADI, and its structure is... .

[0141] Comparative Example 3 This comparative example provides a perovskite solar cell and its fabrication method. The only difference from Example 1 is that the passivation layer material is oPhDADI, and its structure is... .

[0142] Comparative Example 4 This comparative example provides a perovskite solar cell and its fabrication method. The only difference from Example 1 is that the passivation layer material is amidine-substituted propylenediamine iodine, and its structure is as follows: .

[0143] Experimental Example 1 The perovskite solar cells provided in Examples 1-3 and Comparative Examples 1-3 were respectively fabricated into series modules. In order to connect the sub-cells of each example and comparative example in series, the present invention uses the same laser scribing method to divide and connect the sub-cells. The transparent conductive substrate 106 is scribed with line P1, the various functional layers of the perovskite (hole transport layer 105, passivation layer 103, perovskite absorption layer 104 and electron transport layer 102) are scribed with line P3, and the conductive electrode layer 101 is scribed with line P3.

[0144] Each perovskite module assembled in series is encapsulated using the same method: first, butyl rubber is used to surround the battery, then a POE film is laid on top, and finally, a backsheet glass is laminated. The lamination temperature is 115℃ and the lamination time is 8 minutes.

[0145] The encapsulated perovskite modules were subjected to IV performance tests, and the test results are shown in Table 1. Simultaneously, the encapsulated perovskite modules of Example 2 and Comparative Example 1 were subjected to thermal stability tests at 85℃, and the test results are shown in Table 1. Figure 2 As shown.

[0146] The core conditions for IV testing of perovskite modules include: Standard Test Condition (STC) of 1000 W / m 2 Irradiance, 25°C component temperature, AM 1.5G spectrum.

[0147] The 85℃ thermal stability test method is as follows: The core of the 85℃ thermal stability test for perovskite modules is to place the perovskite modules in a constant temperature environment of 85℃ (such as a high temperature chamber) for continuous aging (usually 1000h+), and periodically monitor the IV characteristics, open circuit voltage and other electrical properties and the integrity of the package.

[0148] Table 1 IV Performance of Perovskite Modules

[0149] As shown in Table 1, the experimental results of the three sets of examples 1 and 2, 2 and 3, and 3 of this invention reveal that, based on similar compound skeletons, the passivation material with amidine-substituted compounds in the examples of this invention exhibits a higher short-circuit current density (J / L) compared to the conventional ammonium-substituted passivation material in the comparative examples. SC The larger open-circuit voltage (Voc) and larger fill factor (FF) directly demonstrate that the passivation material provided in the embodiments of the present invention has excellent interface passivation capability and charge transport performance, thereby enabling the embodiments of the present invention to have higher photoelectric conversion efficiency (PCE).

[0150] Furthermore, Comparative Example 4 uses an alkylene chain to replace the arylene structure of the present invention to obtain an amidine-substituted passivation material. Its short-circuit current density, open-circuit voltage, fill factor, and photoelectric conversion efficiency are all lower than those of the examples, indicating that the passivation material provided by the present invention has a more significant performance improvement effect.

[0151] Depend on Figure 2 It can be seen that after 1000 hours at 85°C, the photoelectric conversion efficiency of the perovskite module using a time detector is approximately 95% of the initial efficiency of the amidine-substituted PhDII2 passivation material provided in Example 1, while the ammonium-substituted PhDADI passivation material used in Comparative Example 1 only maintains approximately 85% of the initial efficiency. This indicates that the thermal stability of the passivation material provided in this embodiment is significantly better than that of existing ammonium-substituted passivation materials.

[0152] The present invention provides a passivation material for perovskite thin films, a perovskite solar cell, and a method for its preparation, which have at least the following advantages: First, the inventors discovered that conventional ammonium ligands (such as PDAI2, PEAI, etc.) are prone to deprotonation reactions under photothermal stress, generating volatile amines and halogen vacancies, leading to the failure of passivation materials. However, the amidine-based [C(NH2)2] ligand in this invention... + It possesses a planar conjugated structure and resonance stabilization effect, and its N–H bond dissociation energy (E) a The chemical stability of the passivation material is higher and more difficult to undergo deprotonation. Therefore, this invention creatively introduces an amidine group into the passivation material, which can maintain structural integrity under long-term light exposure and high-temperature operating conditions, effectively avoiding the regeneration of surface vacancies caused by ligand decomposition, thereby significantly improving the long-term operational stability of the device. Compared with existing ammonium-based ligand passivation materials, the passivation material provided by this invention has significantly enhanced chemical stability and deprotonation resistance.

[0153] Secondly, the amidine-substituted aromatic diamine iodide salt provided by this invention not only retains the aromatic amine framework and the uncoordinated Pb on the perovskite surface, but also... 2+The strong π-σ interaction between the perovskite and benzene rings also enables a tetradentate hydrogen bond coordination mode (which can form four hydrogen bonds simultaneously) through the amidine functional group, while traditional ammonium-based passivation materials can only form three hydrogen bonds. This results in stronger surface bonding and multidentate chelation compared to traditional ammonium-based passivation materials. Furthermore, the rigid structure of the benzene ring helps guide ordered termination on the perovskite surface, further reducing interfacial disorder. This multi-layered synergistic effect significantly enhances the bonding energy between the passivation layer and the perovskite surface, improving passivation coverage and durability.

[0154] Furthermore, experimental results show that the perovskite solar cells fabricated using the passivation material of this invention significantly improve both the open-circuit voltage (Voc) and fill factor (FF) while maintaining a high short-circuit current density (see performance comparison of examples and comparative examples). This is attributed to its efficient passivation capability for deep-level surface defects (especially Pb-I antisite defects and halogen vacancies), which significantly reduces nonradiative recombination losses of charge carriers at the interface, thereby improving the photoelectric conversion efficiency of the device. The passivation material provided by this invention effectively suppresses nonradiative recombination and improves open-circuit voltage and fill factor.

[0155] Furthermore, the passivation material provided by this invention exhibits excellent thermal stability, making it suitable for commercial module encapsulation environments. In stability tests, perovskite modules encapsulated with this passivation material maintained over 95% of their initial efficiency after 1000 hours of continuous heating at 85°C, significantly outperforming traditional ammonium-based materials (approximately 85%). This result fully demonstrates the material's outstanding thermal stability, meeting the stringent aging requirements of photovoltaic modules in practical applications, and providing crucial material support for the industrial mass production and long-term reliable operation of perovskite solar cells.

[0156] Finally, the passivation material provided by this invention is compatible with various processing techniques and is easy to integrate into existing production lines. This passivation material is soluble in low-corrosive alcohol solvents (such as hexafluoroisopropanol), making it suitable for low-cost solution-based preparation processes such as spin coating and inkjet printing. It does not damage the underlying perovskite film structure, has a wide process window, good repeatability, and is beneficial for quality control in large-scale production.

[0157] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A passivation material for perovskite thin films, characterized in that, Including molecules having the following general formula: [R-Ph-R]·2HI; wherein the R group is selected from amidine.

2. The passivation material according to claim 1, characterized in that, The structural formula of the passivation material includes: , and At least one of them.

3. The passivation material according to claim 1, characterized in that, The coating concentration of the passivation material is 0.8~1.2 mg / mL.

4. A method for preparing a passivation material as described in any one of claims 1 to 3, characterized in that, The method includes reacting phthalonitrile with methanol under acidic conditions to undergo an imidization reaction, generating phthalimide dihydrochloride in situ; subjecting the phthalimide dihydrochloride to ammonolysis under the action of an ammonia source to generate phthalimidine dihydrochloride; and subjecting the phthalimidine dihydrochloride to an anion exchange reaction with potassium iodide in a hot solvent system. The resulting reactants are then purified to obtain the passivation material. The phthalonitrile includes any one of ortho-phthalonitrile, terephthalonitrile, or iso-phthalonitrile.

5. The preparation method according to claim 4, characterized in that, The imino esterification reaction process includes: mixing the phthalonitrile and the methanol to obtain a first mixture, adding hydrochloric acid or a hydrochloric acid reaction precursor to the first mixture to carry out the reaction, and controlling the reaction temperature to be <5°C; the hydrochloric acid reaction precursor is acetyl chloride; And / or, the ammonolysis reaction process includes: dissolving the phenylenediamine dihydrochloride in methanol to obtain a second mixture, adding an ammonia source to the second mixture, mixing, cooling for 5-15 minutes, and then heating to react; And / or, the anion exchange reaction process includes: mixing the benzodiazepine dihydrochloride with methanol to obtain a third mixture, adding potassium iodide solution to the third mixture, then heating under reflux to react, filtering while hot after the reaction is completed, and concentrating the filtrate under reduced pressure.

6. A perovskite solar cell, characterized in that, It includes a transparent conductive substrate, a hole transport layer, a perovskite absorption layer, an electron transport layer and a conductive electrode layer stacked sequentially, and at least one stacked surface of the perovskite absorption layer is provided with a passivation layer. The material of the passivation layer includes the passivation material as described in any one of claims 1 to 3.

7. The perovskite solar cell according to claim 6, characterized in that, The thickness of the passivation layer is 1~2nm.

8. A method for preparing a perovskite solar cell as described in claim 6 or 7, characterized in that, The method includes sequentially coating the hole transport layer, the perovskite absorption layer, the electron transport layer, and the conductive electrode layer onto the surface of the transparent conductive substrate; Furthermore, at least one layer surface of the perovskite absorber layer is coated with the passivation layer.

9. The preparation method according to claim 8, characterized in that, The preparation of the passivation layer includes dissolving the passivation material in an alcohol solvent to obtain a passivation layer solution, applying the passivation layer solution to the surface of the perovskite absorber layer, and then performing an annealing treatment.

10. The preparation method according to claim 9, characterized in that, Includes at least one of the following features: 1) The alcohol solvent includes at least one of hexafluoroisopropanol, isopropanol, and ethanol; 2) In the passivation layer solution, the concentration of the passivation material is 0.8~1.2 mg / mL; 3) The annealing temperature of the passivation layer solution is 90~110℃, and the annealing time is 8~12min.

Images