Hu Guangcai, Zhao Ziyue, Shen Yang, Wang Yong, Yang Deren
State Key Laboratory of Silicon and Advanced Semiconductor Materials, School of Materials Science and Engineering, and Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou, Zhejiang, 310027, P. R. China.
College of Optical and Electronic Technology, China Jiliang University, Hangzhou, 310018, P. R. China.
Small. 2025 Jun;21(23):e2502025. doi: 10.1002/smll.202502025. Epub 2025 Apr 14.
Formamidinium lead iodide (FAPbI) perovskite, one of the most promising light-absorbing materials, faces substantial stability issues, including FA organic component volatilization and undesirable phase transition between corner-sharing and face-sharing [PbI] octahedra. Especially, the asymmetric hydrogen bonding, arising from oriented and irregularly spinning FA cation, accelerates these transformations, compromising both the efficiency and long-term stability of FAPbI PSCs. Herein, a robust strategy is reported to stabilize FAPbI perovskite by using tricyclohexylphosphine trifluoromethanesulfonate (CyPHSOCF ) to strengthen hydrogen bonds within FA and alleviate octahedral deformation. The hydrogen-bonding capacity of CyPH effectively constrains and stabilizes orientated FA through strong hydrogen bonds (F─H, N─H), while the strong electronegative SOCF ion modifies [PbI] octahedral deformation by diversified covalent bonds (Pb─F, Pb─O) and releases the internal stress of the lattice. As such, the resulting FAPbI demonstrates mitigated organic volatilization and suppressed phase transition, significantly enhancing phase stability under thermal/humidity stress conditions. Moreover, because of co-regulated FA cation and octahedral lattice, FAPbI perovskite exhibits improved carrier dynamics and better matched energy-level alignment with carrier transport layers. The optimized FAPbI-based PSCs deliver an impressive efficiency of 25.93% and exhibit exceptional stability, retaining 97% of initial efficiency after over 1500 h maximum power point tracking.
甲脒碘化铅（FAPbI）钙钛矿是最具潜力的吸光材料之一，但面临着诸多稳定性问题，包括FA有机成分挥发以及角共享和面共享[PbI]八面体之间不良的相变。特别是，由取向且不规则旋转的FA阳离子产生的不对称氢键加速了这些转变，损害了FAPbI钙钛矿太阳能电池的效率和长期稳定性。在此，报道了一种稳健的策略，通过使用三氟甲磺酸三环己基膦（CyPHSOCF）来稳定FAPbI钙钛矿，以加强FA内部的氢键并减轻八面体变形。CyPH的氢键能力通过强氢键（F─H，N─H）有效地约束和稳定取向的FA，而强电负性的SOCF离子通过多种共价键（Pb─F，Pb─O）改变[PbI]八面体变形并释放晶格内应力。因此，所得的FAPbI表现出减轻的有机挥发和抑制的相变，在热/湿度应力条件下显著提高了相稳定性。此外，由于FA阳离子和八面体晶格的共同调节，FAPbI钙钛矿表现出改善的载流子动力学以及与载流子传输层更好匹配的能级排列。优化后的基于FAPbI的钙钛矿太阳能电池实现了25.93%的令人印象深刻的效率，并表现出卓越的稳定性，在超过1500小时的最大功率点跟踪后仍保留97%的初始效率。
