Effects of organic cations on the defect physics of tin halide perovskites. Issue 29 (10th July 2017)

• Record Type: Journal Article
• Authors: Shi, Tingting; Zhang, Hai-Shan; Meng, Weiwei; Teng, Qiang; Liu, Meiyue; Yang, Xiaobao; Yan, Yanfa; Yip, Hin-Lap; Zhao, Yu-Jun
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 29(2017)
• Page Start: 15124
• Page End: 15129
• Publication Date: 2017-07-10
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c7ta02662e
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : The schematic diagram of different Sn-5s and I-5p antibonding strengths of FASnI3 and MASnI3 due to various bond lengths of Sn–I. Abstract : Tin (Sn) halide perovskite absorbers have attracted much interest because of their nontoxicity as compared to their lead (Pb) halide perovskite counterparts. Recent progress shows that the power conversion efficiency of FASnI3 (FA = HC(NH2 )2 ) solar cells prevails over that of MASnI3 (MA = CH3 NH3 ). In this paper, we show that the organic cations, i.e., FA and MA, play a vital role in the defect properties of Sn halide perovskites. The antibonding coupling between Sn-5s and I-5p is clearly weaker in FASnI3 than in MASnI3 due to the larger ionic size of FA, leading to higher formation energies of Sn vacancies in FASnI3 . Subsequently, the conductivity of FASnI3 can be tuned from p-type to intrinsic by varying the growth conditions of the perovskite semiconductor; in contrast, MASnI3 shows unipolar high p-type conductivity independent of the growth conditions. This provides a reasonable explanation for the better performance of FASnI3 -based solar cells in experiments with respect to the MASnI3 -based solar cells.