High‐Efficiency Perovskite Solar Cells with Imidazolium‐Based Ionic Liquid for Surface Passivation and Charge Transport. (23rd December 2020)

• Record Type: Journal Article
• Authors: Zhu, Xuejie; Du, Minyong; Feng, Jiangshan; Wang, Hui; Xu, Zhuo; Wang, Likun; Zuo, Shengnan; Wang, Chenyu; Wang, Ziyu; Zhang, Cong; Ren, Xiaodong; Priya, Shashank; Yang, Dong; Liu, Shengzhong (Frank)
• Is Part Of: Angewandte Chemie. Volume 133:Number 8(2021)
• Page Start: 4284
• Page End: 4290
• Publication Date: 2020-12-23
• Subjects: energy levels -- ionic liquids -- passivation -- perovskites -- stability; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202010987
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Surface defects have been a key constraint for perovskite photovoltaics. Herein, 1, 3‐dimethyl‐3‐imidazolium hexafluorophosphate (DMIMPF6 ) ionic liquid (IL) is adopted to passivate the surface of a formamidinium‐cesium lead iodide perovskite (Cs0.08 FA0.92 PbI3 ) and also reduce the energy barrier between the perovskite and hole transport layer. Theoretical simulations and experimental results demonstrate that Pb‐cluster and Pb‐I antisite defects can be effectively passivated by [DMIM] + bonding with the Pb 2+ ion on the perovskite surface, leading to significantly suppressed non‐radiative recombination. As a result, the solar cell efficiency was increased to 23.25 % from 21.09 %. Meanwhile, the DMIMPF6 ‐treated perovskite device demonstrated long‐term stability because the hydrophobic DMIMPF6 layer blocked moisture permeation. Abstract : An ionic liquid, 1, 3‐dimethyl‐3‐imidazolium hexafluorophosphate (DMIMPF6 ), was used to passivate a perovskite to decrease the defects of Pb‐cluster and Pb‐I antisite, thereby reducing the energy barrier between the perovskite and hole transport layer. A perovskite solar cell attained a 23.25 % efficiency with a high stability due to hydrophobic DMIMPF6 .