Pseudohalide-Induced Moisture Tolerance in Perovskite CH3NH3Pb(SCN)2I Thin Films

• Published in: Angewandte Chemie International Edition Vol. 54; no. 26; pp. 7617 - 7620
• Main Authors: Jiang, Qinglong, Rebollar, Dominic, Gong, Jue, Piacentino, Elettra L., Zheng, Chong, Xu, Tao
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 22.06.2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: moisture tolerance; perovskite phases; pseudohalides; solar cells; Solar energy; Thin films; thiocyanates
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201503038

Two pseudohalide thiocyanate ions (SCN−) have been used to replace two iodides in CH3NH3PbI3, and the resulting perovskite material was used as the active material in solar cells. In accelerated stability tests, the CH3NH3Pb(SCN)2I perovskite films were shown to be superior to the conventional CH3NH3PbI3 films as no significant degradation was observed after the film had been exposed to air with a relative humidity of 95 % for over four hours, whereas CH3NH3PbI3 films degraded in less than 1.5 hours. Solar cells based on CH3NH3Pb(SCN)2I thin films exhibited an efficiency of 8.3 %, which is comparable to that of CH3NH3PbI3 based cells fabricated in the same way. The replacement of two iodides by two pseudohalide thiocyanate ions in CH3NH3PbI3 results in a perovskite material with superior tolerance to moisture when used as the active material of a solar cell. For the CH3NH3Pb(SCN)2I perovskite films, no significant degradation was observed after the film had been exposed to air with a relative humidity of 95 % for over four hours, whereas the CH3NH3PbI3 films degraded in less than 1.5 hours.