【作者】 张林；

【导师】 杨英； 朱刘；

【作者基本信息】 中南大学 ， 材料与化工（专业学位）， 2023， 硕士

【摘要】 钙钛矿/硅叠层太阳能电池光电转换效率（Power Conversion Efficiency,PCE）已经突破32%,叠层太阳能电池未来有可能成为研究和应用的主流电池。其中有机-无机杂化钙钛矿太阳能电池（Perovskite Solar Cells,PSCs）中存在易挥发的有机阳离子,使得器件在高温条件中表现出化学不稳定性。无机钙钛矿体系则将无机金属阳离子Cs⁺替换有机阳离子而有效地解决这一难题,进而显著提高了热稳定性。CsPbIBr₂的带隙约为2.10 e V,是理想的三结叠层电池顶电池材料,具备有优异的稳定性。然而CsPbIBr₂的结晶、成膜以及相稳定性受环境中湿度的影响显著,因此本文研究了湿度对CsPbIBr₂钙钛矿太阳能电池的影响机制,并采用化学浴沉积（Chemical Bath Deposition,CBD）修饰和制备电子传输层以提高光电性能。本文主要工作和结论如下:（1）CsPbIBr₂湿膜在制备过程中与湿度作用可以促进低温结晶,而CsPbIBr₂干膜在湿度空气中热处理可有效提高电池的光电性能。通过对比不同湿度条件下制备的CsPbIBr₂薄膜,发现在制备过程中,H₂O与二甲基亚砜（Dimethyl Sulfoxide,DMSO）相互作用使得Pb Br₂的层间距增加,促进Cs I进入Pb Br₂晶格内形成CsPbIBr₂。在RH≥40%的湿度条件下,由于Pb Br₂溶解度降低而析出引起的“小岛”效应显著降低了薄膜的覆盖率,导致空穴传输层（Hole Transport Layer,HTL）和电子传输层（Electron Transport Layer,ETL）之间相互接触,器件的光电性能下降。干膜在湿度空气中150°C热处理时,由于O₂与未配位的Pb形成Pb O,缓慢钝化缺陷减少了缺陷密度,改善了载流子的传输性能,提高了CsPbIBr₂ PSCs的开路电压、填充因子。通过系统地优化后,CsPbIBr₂ PSCs的光PCE提高至10.79%,未封装的器件在RH≤25%的空气中储存179天仍保持初始效率的97.8%。（2）SnCl₂·2H₂O CBD制备的ETL可有效阻挡空穴通过,C基CsPbIBr₂ PSCs的PCE从4.22%提升至9.04%。采用CBD界面修饰基于不同Sn源制备的底层Sn O₂,新构建的粗糙表面与CsPbIBr₂薄膜形成良好的界面接触,其中的Cl^-不仅可以钝化Sn O₂层中的V_o^··,还能与CsPbIBr₂形成相干中间层,提高钙钛矿的结晶度,促进载流子的界面传输,从而将PCE从4.22%提高到8.03%。进一步优化Sn Cl₂·2H₂O的浓度并采用纯CBD制备ETL,以近红外材料HJF 14修饰CsPbIBr₂/C界面,进一步将PCE提升至9.04%。图33幅,表21个,参考文献178篇更多还原

【Abstract】 The power conversion efficiency（PCE）of perovskite/silicon tandem solar cells has surpassed 32%,positioning them as potential mainstream candidates for research and practical applications.However,the presence of volatile organic cations in organic-inorganic hybrid perovskite solar cells（PSCs）introduces chemical instability under high-temperature conditions.To address this challenge,inorganic perovskite systems replace the organic cations with inorganic metal cations,such as Cs⁺,effectively improving thermal stability.CsPbIBr₂ with a bandgap of approximately 2.10 e V serves as an ideal top-cell material for triple-junction tandem solar cells,demonstrating excellent stability However,the crystallization,film formation,and phase stability of CsPbIBr₂ are significantly influenced by environmental humidity.This study investigates the impact of humidity on CsPbIBr₂ all-inorganic perovskite solar cells and explores strategies to enhance their optoelectronic properties.Specifically,chemical bath deposition（CBD）modification are employed to improve the performance.The main work and conclusions of this thesis were as follows.（1）Moisture triggered fast crystallization of wet CsPbIBr₂ film in low temperature preparation process,while post thermal treatment of CsPbIBr₂dry thin films in low humidity air could stably and effectively improve the photoelectric performance.By comparing CsPbIBr₂ films prepared under different humidity conditions,it was discovered that during the preparation of wet films,the interaction between H₂O and dimethyl sulfoxide（DMSO）increased the interlayer spacing of Pb Br₂,which promoted the entry of Cs I into the Pb Br₂ lattice to form CsPbIBr₂ clusters.However,under a condition with relative humidity（RH）greater than 40%,an"island"effect caused by the precipitation of Pb Br₂ from precursor solution was domiant,which reducing the coverage of the thin film and leading to mutual contact between the hole transport layer（HTL）and electron transport layer（ETL）with a decline in the photoelectric performance of PSCs.Moreover,when the dry film was thermally treated at 150°C under humid air,reacted with the uncoordinated Pb to form Pb O slowly and orderly,reducing the film’s defect density,improving the charge carrier transport properties,and enhancing the open-circuit voltage and fill factor of PSCs.Herein,a champion power conversion efficiency（PCE）of CsPbIBr₂ PSCs 10.79%was obtained,and unencapsulated device remained 97.8%of its initial efficiency after 179 days of storage in low humidity air.（2）The SnCl₂·2H₂O CBD-prepared ETL effectively inhibits hole transport and enhanced the PCE of C-based CsPbIBr₂ PSCs from 4.22%to9.04%.By modifying the underlying Sn O₂ with CBD interfacial treatment using different Sn sources,the newly created rough surface enabled good interfacial contact with the CsPbIBr₂ film.The Cl^-species not only passivated the Vo^··defects in the Sn O₂ layer,but also formed a coherent interlayer with CsPbIBr₂,leading to improved crystallinity and enhanced interfacial transport of carriers,resulting in an increased PCE from 4.22%to 8.03%.Further optimization of the Sn Cl₂·2H₂O concentration and the use of pure CBD for ETL preparation,combined with modification of the CsPbIBr₂/C interface using the near-infrared materials HJF 14,further boosted the PCE to 9.04%.There are 33 figures,21 tables and 178 references.更多还原