Direct observation of cation-exchange in liquid-to-solid phase transformation in FA1-xMAxPbI3 based perovskite solar cells

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review

8 Scopus Citations
View graph of relations

Detail(s)

Original languageEnglish
Pages (from-to)9081-9088
Journal / PublicationJournal of Materials Chemistry A
Volume6
Issue number19
Online published11 Apr 2018
Publication statusPublished - 21 May 2018

Abstract

Mixed-organic-cation FA1-xMAxPbI3 perovskites are currently attracting intensive attention for their high photovoltaic performance. However, FA1-xMAxPbI3 usually has an undesired non-perovskite phase leading to a compromised efficiency, and a facile strategy to achieve pure-phase FA1-xMAxPbI3 has been rarely reported. Here, we demonstrate a facile approach to form δ-phase free FA1-xMAxPbI3 using a non-stoichiometric precursor solution. It is found that a small amount of excess methylammonium iodide (MAI) added to the precursor solution has a profound effect on perovskite crystallization during the liquid-to-solid phase transformation. Using an in situ photoluminescence spectroscopy measurement, it is found that the excess MAI can promote the formation of FA1-xMAxPbI3 and facilitate the cation-exchange between organic FA+ and MA+ during the film formation. Based on the optimized pure-phase FA1-xMAxPbI3, the perovskite solar cells exhibit an encouraging power conversion efficiency (PCE) of 17.40%. This study demonstrates a facile method to achieve high performance FA dominating mixed-organic-cation perovskite devices while providing insight into the ion-exchange process during perovskite crystallization.

Citation Format(s)

Direct observation of cation-exchange in liquid-to-solid phase transformation in FA1-xMAxPbI3 based perovskite solar cells. / Xie, Yue-Min; Yu, Binbin; Ma, Chunqing; Xu, Xiuwen; Cheng, Yuanhang; Yuan, Shuai; Wang, Zhao-Kui; Chandran, Hrisheekesh Thachoth; Lee, Chun-Sing; Liao, Liang-Sheng; Tsang, Sai-Wing.

In: Journal of Materials Chemistry A, Vol. 6, No. 19, 21.05.2018, p. 9081-9088.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalNot applicablepeer-review