【作者】 杨明；

【导师】 臧志刚；

【作者基本信息】 重庆大学 ， 光学工程， 2024， 硕士

【摘要】 有机-无机杂化钙钛矿太阳能电池（PSCs）在近十年内实现了显著的效率提升,从2009年的3.8%跃升至2023年的26.1%,与晶体硅太阳能电池的效率相当。然而,由于其有机成分在光照、高湿、高温环境下的不稳定性,这些电池的进一步发展受到了限制。为了解决这一问题,研究者们采用了铯（Cs）金属元素代替A位有机成分,制备了无机卤化物CsPbX₃（X:I、Br或杂化卤化物）薄膜,这显著提升了热稳定性。在无机钙钛矿体系中,特别是混合卤素CsPbIBr₂电池,其短路电流已经接近理论极限,但由于载流子动力学管理不当,开路电压和填充因子的进一步提升受到限制,导致效率低下。此外,CsPbIBr₂薄膜在持续光照下会在晶界位置发生卤素离子移动,形成富I相和富Br相,产生相分离现象,严重影响稳定性。针对这些问题,本研究以反式无机CsPbIBr₂ PSCs为研究对象,通过引入自组装分子空穴传输层和上界面修饰等手段,开展了钙钛矿薄膜与载流子传输层间的电荷提取、能级匹配优化以及相分离抑制的研究工作。具体研究工作包括:（1）深入探究了三种自组装分子空穴传输材料（Meo-2PACz、2PACz和Me-4PACz）对CsPbIBr₂薄膜质量、空穴传输层/钙钛矿界面的载流子传输行为和光伏性能的影响。结果显示,Meo-2PACz展现出了最优性能,能够显著降低CsPbIBr₂PSCs的缺陷态密度,最终将光电转换效率从7.89%提升至10.51%。（2）研究了不同碳链长度卤化双胺分子对CsPbIBr₂薄膜上界面及其太阳能电池性能的作用机制。结果显示,1,3-二氨基丙烷二氢碘酸盐（PDAI₂）的钝化能力最强,能够有效地与薄膜表面的缺陷态结合,减少晶界的缺陷密度,并提高载流子提取效率。经PDAI₂处理的器件,其光电转换效率显著提升,最高效率从10.51%提升至12.48%,实现了1.296 eV开路电压和12.05 mA·cm^-2短路电流密度。综上所述,本研究针对无机钙钛矿太阳能电池的效率低下和光致相分离问题,通过引入自组装分子空穴传输层和界面修饰,优化了载流子传输层与钙钛矿薄膜之间的电荷提取和能级匹配,并抑制了相分离问题。这些优化策略为推动无机钙钛矿太阳能电池技术的发展提供了重要指导。更多还原

【Abstract】 Organic-inorganic hybrid perovskite solar cells（PSCs）have achieved significant efficiency improvements in the last decade,soaring from 3.8% in 2009 to 26.1% in 2023,comparable to the efficiency of crystalline silicon solar cells.However,the further development of these cells has been limited due to the instability of their organic components under conditions of light exposure,high humidity,and high temperature.To address this issue,researchers have used the cesium（Cs）metal element to replace the A-site organic components,preparing inorganic halide CsPbX₃（X:I,Br,or hybrid halide）thin films,which significantly improve thermal stability.In the inorganic perovskite system,especially for mixed halide CsPbIBr₂ cells,the short circuit current has approached the theoretical limit.However,due to improper management of carrier dynamics,further improvements in open circuit voltage and fill factor are limited,resulting in low efficiency.In addition,CsPbIBr₂ films undergo halogen ion movement at grain boundaries under continuous light exposure,forming I-rich and Br-rich phases,leading to phase segregation,which severely affects stability.In response to these issues,this study focuses on the inverted type inorganic CsPbIBr₂ PSCs,and through the introduction of self-assembled molecular hole transport layers and upper interface modifications,it has conducted research on charge extraction,energy level matching optimization,and phase segregation suppression between the perovskite film and the carrier transport layer.The specific research work includes:（1）An in-depth exploration of the effects of three self-assembled molecular hole transport materials（Meo-2PACz,2PACz,and Me-4PACz）on the quality of CsPbIBr₂films,the carrier transport behavior at the hole transport layer/perovskite interface,and photovoltaic performance.The results show that Meo-2PACz exhibits the best performance,significantly reducing the defect state density of CsPbIBr₂ PSCs and ultimately increasing the photoelectric conversion efficiency from 7.89%to 10.51%.（2）A study on the mechanism of action of halogenated diamine molecules with different carbon chain lengths on the upper interface of CsPbIBr₂ films and their solar cell performance.The results indicate that 1,3-diaminopropane dihydroiodate（PDAI₂）has the strongest passivation ability,effectively combining with the defect states on the film surface,reducing the defect density at the grain boundaries,and improving carrier extraction efficiency.Devices treated with PDAI₂ exhibit a significant increase in photoelectric conversion efficiency,with the highest efficiency increasing from 10.51% to 12.48%,achieving an open-circuit voltage of 1.296 eV and a short-circuit current density of 12.05 mA·cm^-2.In summary,this study addresses the issues of low efficiency and photoinduced phase segregation in inorganic perovskite solar cells by introducing self-assembled molecular hole transport layers and interface modifications,optimizing charge extraction and energy level matching between the carrier transport layer and the perovskite film,and suppressing phase segregation.These optimization strategies provide important guidance for promoting the development of inorganic perovskite solar cell technology.更多还原