Surface versus Bulk Currents and Ionic Space-Charge Effects in CsPbBr<sub>3</sub> Single Crystals
Osbel Almora, Gebhard J. Matt, Albert These, Andrii Kanak, Ievgen Levchuk, Shreetu Shrestha, Andres Osvet, Christoph J. Brabec, Germà García-Belmonte
Abstract
with a negative voltage bias dependency. By means of a guard ring (GR) configuration, we separate bulk and surface mobilities showing significant qualitative and quantitative transport differences. Our experiments of current transients and impedance spectroscopy indicate the formation of several regimes of space-charge-limited current (SCLC) associated with mechanisms similar to the Poole-Frenkel ionized-trap-assisted transport. We show that the ionic-SCLC seems to be an operational mode in this lead halide perovskite, despite the fact that experiments can be designed where the contribution of mobile ions to transport is negligible.