Interfacial charge transport in MAPbI3 perovskite on ZnO

Interfacial charge transport of methylammonium lead iodide (MAPbI3) perovskite close to the ZnO nanocrystal (NC) interface was probed using a field effect transistor (FET) device in which a perovskite/ZnO bilayer was formed between the source and drain electrodes. Through electric field gating the role of the underlying ZnO NC layer on the charge transport in the MAPbI3 perovskite was elucidated. In the presence of the ZnO NC layer, the FET was turned on earlier indicating that the carrier concentration at zero gate voltage is higher than that without a ZnO NC layer. This is attributed to reduced trap density by passivating the interfacial traps at the SiO2/perovskite interface. No significant change was observed for the FET mobility depending on the presence of the ZnO NC layer.