Observation of Long-Term Stable Response in MAPbBr3 Single Crystals Monitored through Displacement Currents under Varying Illumination

Abstract

Long life of perovskite devices in working conditions remains the bottleneck for technology application. Stable charge carriers’ transport together with nonreactive contact materials contributes to the increase of the device operation time. Still, an appropriate model for transport carrier mechanisms is needed because of the complex ionic–electronic interplay. Herein, methylammonium lead bromide perovskite single crystals are used to analyze the current flowing across the perovskite sample after biasing. Two methods are performed: 1) direct measurement using an amperemeter and 2) indirect method by means of an induced potential in a reference capacitor. Because of the continuity of the current, the latest method measures direct current through the sample by monitoring displacements currents. Intriguing features are observed: the displacement currents result in stable and highly reproducible responses for long-term biasing (≈2000 s), while the direct measurements produce larger and exponentially increasing current dependence on time. These findings highlight the nontrivial effect of contacting and measuring procedures in exploring thick perovskite electrical response.