实验室董维，乔文成等同学在Nano-Micro Letters期刊发表了题为Surface Passivation and Energetic Modification Suppress Nonradiative Recombination in Perovskite Solar Cells的文章，通讯作者为姚叶锋老师，保秦烨老师以及丁黎明老师（国家纳米中心），在线发表日期为2022年4月19日（https://link.springer.com/article/10.1007/s40820-022-00854-0）。
Surface passivation via post-treatment is an important strategy for improving power conversion efficiency and operational stability of perovskite solar cells (PSCs). However, so far the interaction mechanisms between passivating additive and perovskite are not well understood. Here, we report the atomic-scale interaction of surface passivating additive 2,2-difluoroethylammonium bromine (2FEABr) on the MAPbI3. It is found that the bulky 2FEA+ cations tend to distribute at film surface, while the Br- anions diffuse from surface into bulk. A combination of 19F, 207Pb and 2H solid-state NMR further reveal the Br- anions’ partial substitution for the I- sites, the restricted motion of partial MA+ cations, and the firmed perovskite lattices, which would improve charge transport and stability of the perovskite films. Optical spectroscopy and ultraviolet photoelectron spectroscopy demonstrate that the 2FEABr induced surface passivation and energetic modification suppress the nonradiative recombination loss. These findings enable the efficiency of the p-i-n structured PSC significantly increasing from 19.44% to 21.06%, accompanied by excellent stability.Our work further establishes more knowledge link between passivating additive and PSC performance.
