Hysteric photo-conduction and negative differential resistance in cesium lead bromide

For the perovskite halides, current voltage hysteresis is the biggest puzzle to be solved before industrialization in spite of promising features for future photo-voltaic applications. All the possible causes, from the classical (viz., morphology, defects, slow transient capacitance, etc.) to quantum (viz., spin–orbit interaction) ones, are investigated. However, its origin is still under debate, as possibilities showed some ambiguity on the science known until now. In the present work, we have studied the time dependent photo-conduction behavior of $CsPbBr3$ in continuous illumination of AM 1.5 G Sun light for 3 h. We observed a negative differential resistance for a forward scanned current–voltage curve in AM 1.5 G Sun light. Our investigations suggest that the photo-current voltage hysteresis is primarily affected by the thermionic-field emission, which slows down the drift velocity of hot charge carriers with field applications. This study will further lead the scientific community to investigate whether this slowdown in drift velocity is related to the Gunn effect or the Rashba effect.