Affiliation:
1. School of Physics Southeast University Nanjing 211189 China
2. Department of Materials Science & Engineering City University of Hong Kong Kowloon 999077 Hong Kong
Abstract
AbstractTin organic–inorganic halide perovskites (tin OIHPs) possess a desirable band gap and their power conversion efficiency (PCE) has reached 14 %. A commonly held view is that the organic cations in tin OIHPs would have little impact on the optoelectronic properties. Herein, we show that the defective organic cations with randomly dynamic characteristics can have marked effect on optoelectronic properties of the tin OIHPs. Hydrogen vacancies originated from the proton dissociation from FA [HC(NH2)2] in FASnI3 can induce deep transition levels in the band gap but yield relatively small nonradiative recombination coefficients of 10−15 cm3 s−1, whereas those from MA (CH3NH3) in MASnI3 can yield much larger nonradiative recombination coefficients of 10−11 cm3 s−1. Additional insight into the “defect tolerance” is gained by disentangling the correlations between dynamic rotation of organic cations and charge‐carrier dynamics.