Tang Xianglan, Lin Yun, Wan Fang, Deng Wen, Wang Lei, Hu Ting, Hu Xiaotian, Zhang Lin, Ouyang Fangping, Liu Biao, Yang Junliang, Chen Zhihui, Yang Bin, Ding Liming, Wang Xiao, Pang Shuping, He Jun, Chen Yiwang, Yuan Yongbo
Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha, Hunan 410083, P. R. China.
Jiangxi Key Laboratory of Work Safety of Risk Monitoring and Prevention, Jiangxi Academy of Emergency Management Science (JXAEMS), 1519 Chuntai Avenue, Nanchang 330001, P. R. China.
ACS Nano. 2025 Jul 15;19(27):24865-24873. doi: 10.1021/acsnano.5c03211. Epub 2025 Jul 1.
For the quasi-two-dimensional (Q-2D) perovskites containing formamidinium cations (FA), the chemical reaction between FA and amine-based organic spacers deteriorates the phase purity and repeatability of perovskite solar cells (PSCs), but it has attracted little attention so far. In this work, the aging process of the 1,3-propanediamine- (PDA-) and FA-based Dion-Jacobson (DJ) type Q-2D perovskite precursor has been investigated. The deprotonated PDA interacts with the FA via its two terminal amines successively to form a ring molecule, giving rise to a highly insoluble complex with lead iodide and causing reversible precursor aging. Adding a small amount of acid is demonstrated as a general route to eliminate the FA-related reactions in the precursor. In our study, the used methanesulfonic acid (MSA) effectively eliminates the precursor aging in both PDA- and butylamine (BA)-containing Q-2D perovskite films and meanwhile passivates the undercoordinated Pb with its S═O group, leading to both improved power conversion efficiency (PCE) of solar cells and precursor stability. FA-based Q-2D PSCs have been enhanced from 14.60% to 18.26%.
