Optical and electrical signatures of charge trapping in hybrid perovskite MAPbBr3 single crystals

Abstract

Understanding the dynamics of charge trapping and detrapping is essential for improving the optoelectronic performance of hybrid perovskite materials. In this study, we investigate temperature-dependent luminescence and electrical transport in single crystals of methylammonium lead bromide (MAPbBr3). Radioluminescence and photoluminescence spectra collected from 8 to 300 K reveal multiple emission features, with several trap-related peaks disappearing at specific temperatures. These changes correlate with thermoluminescence measurements, which identify two prominent glow peaks corresponding to trap levels with activation energies of 69 and 126 meV, suggesting thermally driven release of carriers. Complementary current–voltage measurements performed at cryogenic temperatures exhibit clear trap-filled-limit and space-charge-limited current regimes, emerging only above 100 K. The absence of trap-filled-limit behavior at lower temperatures supports the presence of traps that hinder charge transport, consistent with the observed luminescence dynamics. Together, these results provide a coherent picture of thermal detrapping and carrier recombination in MAPbBr3, offering insights relevant to perovskite-based optoelectronic applications.