Application of Aniracetam in the Preparation of Water-resistant Perovskite Thin Films

Abstract

This invention discloses the application of aniracetam in the preparation of perovskite thin films resistant to water vapor erosion. Aniracetam is soluble in common perovskite solvents / antisolvents but insoluble in water, allowing it to be adapted to different perovskites without complex optimization. It can enrich grain boundaries, adhere to surfaces to block water vapor, reduce film defects, extend carrier lifetime, and improve battery efficiency and stability. Furthermore, modification with solvents such as isopropanol can ensure the film structure. In terms of performance, the PCE of batteries containing aniracetam is higher than that of the control group. Blending modification (0.5~1 mg / ml concentration, 400 μm thickness) yields the best PCE, reaching 23.8%~24.1%, which is superior to surface coatings. Moreover, this method is simple to operate and easily industrialized, providing support for stable and efficient perovskite devices.

Description

Technical Field

[0001] This invention relates to the field of perovskite photovoltaic technology, specifically to the application of aniracetam in the preparation of waterproof perovskite thin films. Background Technology

[0002] Perovskite solar cells, as a new generation of photovoltaic technology, have achieved a photoelectric conversion efficiency exceeding 26%, approaching the theoretical limit of traditional crystalline silicon cells. However, their commercialization is still limited by non-radiative recombination problems caused by grain boundaries and surface defects. During solution-based perovskite film preparation, rapid crystallization at grain boundaries easily generates defects such as ion vacancies and interstitial atoms. These defects act as carrier recombination centers, reducing cell performance parameters. While existing passivation technologies achieve partial defect suppression through Lewis acid / base compounds or polymer modification, three major technical bottlenecks exist: First, insufficient matching between the passivating agent and the perovskite lattice; for example, traditional Lewis acids (such as PbI2) easily release defects again at high temperatures, leading to poor long-term stability. Second, a lack of additive dispersion control technology; in existing solution-based processes, additives tend to agglomerate, forming micron-sized particles. Third, insufficient synergy between grain boundary and surface passivation; single-component passivating agents cannot simultaneously cover grain boundaries (three-dimensional defects) and surfaces (two-dimensional defects).

[0003] While existing technologies have made progress in specific scenarios, they still suffer from systemic defects. Taking patent CN113948646A as an example, it achieves surface passivation through the π-π conjugation of polystyrene and perovskite, but it has two major technical shortcomings: First, the polystyrene molecular chain length (Mn=50,000~200,000) does not match the perovskite grain size (200~500nm), resulting in less than 40% coverage at grain boundaries; second, the polarity of the cyclohexane solvent (ε=2.02) differs greatly from that of the perovskite precursor solvent (DMF, ε=36.7), easily inducing phase separation and reducing film uniformity by 20%~30%. Patent CN106033796A uses a one-step doping method with alkali metal salts (such as CsCl), which reduces film roughness, but faces the problem of additive concentration threshold: when Cs... + When the concentration exceeds 0.5 mol%, it easily induces a transformation of the perovskite crystal from the cubic to the tetragonal phase, resulting in a band gap widening of 0.1 eV and a decrease in light absorption efficiency of 18%. Furthermore, existing technologies generally lack consideration for the matching degree between the additive surface energy (γ) and the perovskite (γ≈25 mN / m). When the surface energy difference of the additive is >10 mN / m, pores are easily formed in the film, causing the carrier mobility to decrease to below 0.1 cm² / Vs. These technical shortcomings indicate that existing methods struggle to balance passivation efficiency, film quality, and long-term stability. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention proposes the application of aniracetam in the preparation of perovskite thin films that are resistant to water vapor corrosion. Aniracetam is used as a passivating agent. Aniracetam molecules have good solubility, being soluble in common perovskite solvents and antisolvents, but insoluble in water. During the thin film preparation process, aniracetam molecules can accumulate at the perovskite grain boundaries, preventing water vapor from penetrating into the film interior along the grain boundaries. They can also precisely adhere to the surface of the perovskite film, directly blocking the path of water vapor intrusion from the surface, thereby enhancing the stability of the film and the perovskite solar cells prepared from it.

[0005] To achieve the above objectives, the present invention provides the following technical solution: the application of aniracetam in the preparation of perovskite thin films.

[0006] Furthermore, anisictan was dissolved in a perovskite precursor solution to prepare perovskite thin films.

[0007] Furthermore, an anistetan coating is uniformly coated on the surface of the perovskite film.

[0008] Furthermore, the dosage of anisectane is 0.1 mg / ml to 2 mg / ml.

[0009] Furthermore, the dosages of anisectane are 0.1 mg / ml, 0.3 mg / ml, 0.5 mg / ml, 1 mg / ml, and 2 mg / ml.

[0010] The present invention also provides a perovskite thin film, wherein anisictan is present on the surface or at the grain boundaries of the perovskite thin film.

[0011] Furthermore, the dosage of anisectane is 0.1 mg / ml to 2 mg / ml.

[0012] Furthermore, the dosages of anisectane are 0.1 mg / ml, 0.3 mg / ml, 0.5 mg / ml, 1 mg / ml, and 2 mg / ml.

[0013] The present invention also provides a method for preparing the above-mentioned perovskite thin film, the specific steps of which are as follows: Method 1: Preparation of perovskite precursor solution; Aniracetam is dissolved in the perovskite precursor solution to prepare a perovskite wet film with a thickness of 80μm-150μm, which is then annealed to obtain a perovskite thin film. or Method 2: Prepare a perovskite precursor solution, prepare a perovskite wet film with a thickness of 80μm-150μm, anneal, and obtain a perovskite thin film; An anicester solution was prepared by dissolving anicester in a solvent that does not dissolve perovskite films. An anicester coating was then prepared on the surface of the perovskite film using the anicester solution.

[0014] The present invention also provides a perovskite solar cell, wherein the perovskite thin film is one of the perovskite thin films described above.

[0015] Compared with the prior art, the present invention has at least the following beneficial effects: This invention proposes the application of aniracetam in the preparation of perovskite thin films resistant to water vapor erosion. Aniracetam is soluble in common perovskite solvents and antisolvents, but insoluble in water. It can adapt to different perovskite material surface properties and defect types without the need for complex optimization of passivating agent composition and ratio. It exhibits good dispersibility in perovskite precursor solutions, facilitating the formation of smooth films, reducing roughness and defect state density, extending carrier lifetime, suppressing nonradiative recombination at grain boundaries, and improving the photoelectric conversion efficiency and stability of the battery. Furthermore, it can accumulate at grain boundaries or precisely adhere to the surface, blocking water vapor intrusion, achieving grain boundary and surface passivation, and enhancing the environmental stability of the thin film and the long-term operating performance of the battery.

[0016] Furthermore, solvents that do not dissolve perovskite can be used in the preparation process. An aniracetam layer can be prepared on the surface of the perovskite film using an aniracetam solution. This avoids damage to the already formed film during modification, preserving its original structure and properties. It is particularly beneficial for perovskite systems with poor stability, providing support for the preparation of reliable films from perovskite materials with different properties, broadening the application scenarios, and allowing aniracetam to play a role in more diverse perovskite systems, thus contributing to the construction of more stable and efficient perovskite films. The method of this invention is simple to operate, requires no complex post-processing steps, and is easy to industrialize. It has the advantages of convenient process and scalability in perovskite film preparation applications. Detailed Implementation

[0017] The present invention will be further described below with reference to specific embodiments.

[0018] This invention provides the application of aniracetam in the preparation of perovskite thin films, wherein the molecular structural formula of aniracetam is as follows:

[0019] Specifically, aniracetam is added during the preparation of perovskite thin films. Aniracetam is readily soluble in common perovskite solvents such as N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), allowing it to be directly incorporated into the perovskite precursor solution and dispersed at grain boundaries during film formation. Simultaneously, it is also soluble in perovskite antisolvents such as ethyl acetate, enabling the formation of an aniracetam layer on the perovskite film surface. This achieves passivation of the perovskite film's grain boundaries and surface, fully leveraging the passivation effect. During perovskite film preparation, there is no need for complex optimization of the passivating agent's composition and ratio, allowing it to adapt to different perovskite material surface properties and defect types. Furthermore, aniracetam is insoluble in water, enabling it to form an effective barrier within the perovskite film. When aniracetam molecules are positioned at grain boundaries or the film surface, they significantly inhibit water vapor permeation through hydrophobic interactions, reducing the rate of water-induced perovskite phase decomposition and thus improving the environmental stability of the film and the long-term operating performance of perovskite solar cells.

[0020] The specific steps are as follows: Preparation Method 1 Preparation of perovskite precursor solution; Aniracetam was dissolved in a perovskite precursor solution, and a perovskite wet film with a thickness of 80 μm-150 μm was prepared by spin coating / spray coating / scalpel coating, etc., followed by annealing to obtain a perovskite thin film.

[0021] Perovskite thin films were prepared using Method 1, which utilized the solubility of aniracetam in different solvents. Aniracetam is soluble in common perovskite solvents (DMF, DMSO, etc.) and perovskite antisolvents (ethyl acetate, etc.), but insoluble in water. Aniracetam was dissolved in a perovskite precursor solution to prepare perovskite thin films. This substance is located at the grain boundary in the solid film. Grain boundaries are channels for water vapor to erode the perovskite film. By using this substance, water vapor can be prevented from entering, thereby enhancing the performance of the film and the perovskite battery prepared from it.

[0022] Preparation Method 2 Preparation of perovskite precursor solution; Perovskite wet films with a thickness of 80 μm-150 μm were prepared by spin coating, spray coating, or blade coating, and then annealed to obtain perovskite thin films. An anicester solution was prepared by dissolving anicester in a solvent (isopropanol, hexafluoroisopropanol, etc.) that does not dissolve perovskite films. An anicester layer was then prepared on the surface of the perovskite film using the anicester solution.

[0023] The aniracetam layer prepared using method two adheres precisely to the surface of the perovskite film, directly blocking the path of water vapor intrusion from the surface, thus providing more targeted protection. The use of a solvent that does not dissolve perovskite avoids damage to the formed film during the modification process, preserving the original structure and properties of the film, and is more compatible with perovskite systems with poor stability.

[0024] Preferably, in the two preparation methods described above, the dosage of anisectane is 0.1 mg / ml to 2 mg / ml.

[0025] More preferably, in the two preparation methods described above, the amount of aniracetam added is 0.1 mg / ml, 0.3 mg / ml, 0.5 mg / ml, 1 mg / ml, and 2 mg / ml.

[0026] Preferably, the annealing temperature is 120~180℃, more preferably 130~160℃, and the annealing time is 15~45min, more preferably 25~35min. More preferably, annealing is performed at 100℃ for 30min.

[0027] Preferably, when using spin coating, the rotation speed is controlled at 1000rpm~3000rpm and the coating time is 30s~60s; Preferably, when using a spraying method, the nozzle is 10cm to 20cm away from the substrate, and the spraying pressure is 0.1MPa to 0.3MPa; Preferably, when using a scraping method, the scraping speed is 0.5 mm / s to 5 mm / s, and the substrate temperature is 25℃ to 60℃.

[0028] In summary, the perovskite thin film prepared by this invention exhibits excellent uniformity and density, effectively hindering the recombination of photogenerated carriers by the perovskite light-absorbing layer and improving photoelectric conversion efficiency. Simultaneously, the film's humidity and thermal stability are significantly enhanced, demonstrating good practical value. The perovskite thin film obtained through the above preparation process possesses excellent mechanical strength and chemical corrosion resistance, making it suitable for applications in various complex environments.

[0029] Example 1: A method for preparing anisictan-containing perovskite thin films includes the following steps: (1) Preparation of perovskite precursor solution: Lead iodide, lead bromide, formamidinium iodide and cesium iodide are mixed in a molar ratio of 0.85:0.15:0.78:0.22 and dissolved in a mixed solution of DMF and DMSO in a volume ratio of 4:1. The mixture is stirred at 25°C until completely dissolved to obtain perovskite precursor solution; (2) Adding anisracetam: Add anisracetam with a purity of 99.9% (molecular formula C6H4H4) 15N(CH3)3 (molecular weight 73.15) was dissolved in the perovskite precursor solution prepared in step (1), and the concentration of aniracetam was 0.5 mg / ml; (3) Preparation of perovskite wet film: The mixed solution is spin-coated onto an ITO glass substrate to form a wet film with a thickness of 150 μm; (4) Annealing treatment: The prepared wet film was annealed at 100°C for 3 hours under a nitrogen atmosphere to obtain a perovskite film.

[0030] Example 2: A method for preparing an aniracetam-containing perovskite thin film, which differs from Example 1 in that the concentration of aniracetam is 1 mg / ml.

[0031] Example 3: A method for preparing an aniracetam-containing perovskite thin film, which differs from Example 1 in that the concentration of aniracetam is 2 mg / ml.

[0032] Example 4: A method for preparing an aniracetam-containing perovskite film, which differs from Example 1 in that the concentration of aniracetam is 0.1 mg / ml.

[0033] Example 5: A method for preparing an aniracetam-containing perovskite film, which differs from Example 1 in that the concentration of aniracetam is 0.3 mg / ml.

[0034] Example 6: A method for preparing an aniracetam-containing perovskite film, which differs from Example 1 in that the wet perovskite film thickness is 100 μm.

[0035] Example 7: A method for preparing an aniracetam-containing perovskite film, which differs from Example 1 in that the wet perovskite film thickness is 80 μm.

[0036] Example 8: A method for preparing anisictan-containing perovskite thin films includes the following steps: (1) Preparation of perovskite precursor solution: Lead iodide, lead bromide, formamidinium iodide and cesium iodide are mixed in a molar ratio of 0.85:0.15:0.78:0.22 and dissolved in a mixed solution of DMF and DMSO in a volume ratio of 4:1. The mixture is stirred at 25°C until completely dissolved to obtain perovskite precursor solution; (2) Preparation of perovskite wet film: The perovskite precursor solution was spin-coated onto an ITO glass substrate to form a wet film with a thickness of 150 μm; (3) Annealing treatment: The prepared wet film was annealed at 100°C for 3 hours under a nitrogen atmosphere to obtain a perovskite film. (4) Preparation of anisictan coating: Anisictan was dissolved in isopropanol to prepare an anisictan solution with a concentration of 2 mg / ml. An anisictan coating was uniformly coated on the surface of the perovskite film by spraying. The spraying pressure was 0.2 MPa and the coating thickness was 8 nm.

[0037] Example 9: A method for preparing an aniracetam-containing perovskite film, which differs from Example 8 in that the concentration of aniracetam is 1 mg / ml.

[0038] Example 10: A method for preparing an aniracetam-containing perovskite film, which differs from Example 8 in that the concentration of aniracetam is 0.5 mg / ml.

[0039] Example 11: A method for preparing an aniracetam-containing perovskite film, which differs from Example 8 in that the concentration of aniracetam is 0.3 mg / ml.

[0040] Example 12: A method for preparing an aniracetam-containing perovskite film, which differs from Example 8 in that the concentration of aniracetam is 0.1 mg / ml.

[0041] Example 13: A method for preparing an aniracetam-containing perovskite thin film, which differs from Example 8 in that the wet perovskite film thickness is 100 μm.

[0042] Example 14: A method for preparing an aniracetam-containing perovskite film, which differs from Example 8 in that the wet perovskite film thickness is 80 μm.

[0043] Comparative Example 1 A method for preparing a perovskite thin film, which differs from Example 1, involves modifying the perovskite thin film with phenylethylamine iodide.

[0044] Comparative Example 2 A method for preparing a perovskite thin film, which differs from Example 6, involves dissolving aniracetam in N-methylpyrrolidone.

[0045] Perovskite solar cells were assembled using the perovskite thin films of Examples 1-14 and Comparative Examples 1-2, respectively. The structure of the perovskite solar cells, from bottom to top, is glass / ITO / nickel oxide / perovskite / C60 / BCP / Cu. The specific preparation process is as follows: 1) The substrate is made of glass / ITO. It can be commercially available or prepared by sputtering a 15nm thick layer of ITO onto glass. Before use, the substrate is cleaned by sonication for 15 minutes each with ultrapure water, glass detergent, ultrapure water, and isopropanol. 2) The hole transport layer or the first carrier transport layer is made of nickel oxide. An aqueous solution of 10 mg / ml nickel oxide nanoparticles is prepared on a substrate by spin coating, blade coating, spray coating, etc., to obtain a nickel oxide film with a thickness of 15 nm. 3) Perovskite: Perovskite films from Examples 1-14 and Comparative Examples 1-2 were used respectively; 4) The electron transport layer / blocking layer uses C60 / BCP. C60 / BCP is deposited on a perovskite film containing aniracetam at thicknesses of 20 nm and 3 nm, respectively. 5) The metal electrodes are made of copper, silver, or gold. Copper, silver, or gold electrodes are deposited on the electron transport layer / blocking layer to a thickness of 100 nm. 6) Encapsulation yields perovskite solar cells.

[0046] The photoelectric conversion efficiency of perovskite solar cells was tested, as follows:

[0047] Note: Test conditions were AM1.5G simulated sunlight (100mW / cm²). 2 ), 25℃ room temperature, 3 parallel samples per group, PCE is the average value (error ±0.2%).

[0048] As shown in the table above, the power conversion efficiency (PCE) of all perovskite solar cells containing aniracetam (Examples 1-14) is higher than that of comparative examples 1-2. Among them, the blending modification method (Examples 1-7) is better than the surface coating method (Examples 8-14). The optimal parameters are aniracetam concentration of 0.5 mg / ml to 1 mg / ml and perovskite wet film thickness of 400 μm (Examples 1 and 2), with a PCE of 23.8% to 24.1%. The specific analysis is as follows: First, regarding the effect of aniracetam concentration on PCE, the blend system (Examples 1-5) showed a trend of first increasing and then decreasing, reaching a peak (23.8%-24.1%) at 0.5-1 mg / ml. If the concentration was too low (0.1 mg / ml), the PCE would only be 20.9% because the perovskite lattice defects could not be fully filled. If the concentration was too high (2 mg / ml), the PCE would drop to 22.7% because molecular aggregation would hinder carrier transport. In contrast, the PCE of the coating system (Examples 8-12) increased slightly with increasing concentration, reaching a maximum of 22.5% at 2 mg / ml, but was lower than that of the blend system overall. This is because the coating can only modify surface defects and cannot improve bulk defects.

[0049] Secondly, the influence of perovskite film thickness on PCE is consistent in both systems, but the blend system (Examples 1, 6, 7) performs better, with the highest PCE (23.8%) at a thickness of 400 μm. Thinner films of 100 μm and 200 μm will cause the PCE to decrease due to insufficient light absorption. The coating system (Examples 8, 13, 14) has lower PCE at all thicknesses. This is because the transmission loss caused by bulk defects and thickness is superimposed, making the performance decline more obvious.

[0050] Finally, the advantages of the blending method are clearly evident from the comparative results. At the same concentration (1 mg / ml) and thickness (400 μm), the blended system (Example 2, 24.1%) has a higher PCE than the coating system (Example 9, 22.2%). This is because blending allows aniracetam to be uniformly dispersed within the perovskite while suppressing bulk and surface defects. Furthermore, the modification effect of aniracetam is superior. Example 1 (23.8%) has a higher PCE than Comparative Example 1 (20.7%), due to its stronger binding ability of amino and amide groups to perovskite defects. Solvent selection is also crucial. N-methylpyrrolidone can damage the perovskite crystal structure, resulting in a lower PCE in Comparative Example 2 (19.5%) than in Example 6 (21.3%), which uses a DMF / DMSO mixed solvent. This verifies the compatibility advantage of the mixed solvent.

[0051] In summary, aniracetam demonstrates significant application value in the fabrication of perovskite thin films resistant to water vapor intrusion. It possesses both good solubility and hydrophobic properties, effectively blocking water vapor intrusion by enriching grain boundaries and adhering to surfaces. Furthermore, it is adaptable to various perovskite materials, achieving dual passivation of grain boundaries and surfaces without complex optimization, effectively reducing defect state density and extending carrier lifetime. Moreover, it is simple to operate, requires no complex post-processing, and is easy to industrialize. This application not only provides an effective path to improve the environmental stability of perovskite thin films and the long-term performance of batteries, but also broadens the application scenarios of perovskite materials, laying an important foundation for building stable and efficient perovskite devices.

Claims

1. Application of aniracetam in the preparation of perovskite thin films.

2. The application according to claim 1, characterized in that, Perovskite thin films were prepared by dissolving aniracetam in a perovskite precursor solution.

3. The application according to claim 1, characterized in that, An anistetan coating is uniformly applied to the surface of the perovskite film.

4. The application according to any one of claims 1 to 3, characterized in that, The dosage of anisictan is 0.1 mg / ml to 2 mg / ml.

5. The application according to claim 4, characterized in that, The dosages of aniracetam are 0.1 mg / ml, 0.3 mg / ml, 0.5 mg / ml, 1 mg / ml, and 2 mg / ml.

6. A perovskite thin film, characterized in that, Anistanetan is present on the surface or at the grain boundaries of the perovskite film.

7. The perovskite thin film according to claim 6, characterized in that, The dosage of anisictan is 0.1 mg / ml to 2 mg / ml.

8. The perovskite thin film according to claim 7, characterized in that, The dosages of aniracetam are 0.1 mg / ml, 0.3 mg / ml, 0.5 mg / ml, 1 mg / ml, and 2 mg / ml.

9. A method for preparing a perovskite thin film according to any one of claims 6 to 8, characterized in that, The specific steps are as follows: Method 1: Preparation of perovskite precursor solution; Aniracetam is dissolved in the perovskite precursor solution to prepare a perovskite wet film with a thickness of 80μm-150μm, which is then annealed to obtain a perovskite thin film. or Method 2: Prepare a perovskite precursor solution, prepare a perovskite wet film with a thickness of 80μm-150μm, anneal, and obtain a perovskite thin film; An anicester solution was prepared by dissolving anicester in a solvent that does not dissolve perovskite films. An anicester coating was then prepared on the surface of the perovskite film using the anicester solution.

10. A perovskite solar cell, characterized in that, The perovskite film is one of the perovskite films according to any one of claims 6 to 8 or the perovskite film prepared by the method in claim 9.

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