The study of ion migration in methylammonium lead bromide crystals

Abstract

The Inverse Temperature Crystallization (ITC) and seed-induced method were used to grow high-quality cubic samples within hours using a 1M solution of methylammonium lead bromide (MAPbBr3) samples. The current-voltage (I-V) hysteresis observed within the MAPbBr3 perovskite sample demonstrates anomalous dependence on scan rate and various preconditioning pulses. We investigate this dependence and the relationship of current-transient with slow migrating ions. The current transients fitted using a bi-exponential decay model produced two distinct time constants t1 = 38.4 s and t2 = 6.49 s associated with migrating ionic species. From the Arrhenius plot an activation energy of Ea = 0.410 associated with migrating Br ions was extracted. Future research is required towards the understanding of I-V hysteresis and the link to ion migration in MAPbBr3 perovskite.