Capacitance and Charging Transients at Interfaces in Hybrid Lead Halide Perovskites.

GARCÍA BATLLE, M.; CARAM, J.; OSBEL, A.; ARCE, R. D.; GARCÍA BELMONTE, G.

Conferencia; NanoGE Fall Meeting; 2019

Perovskite-based solar cells constitute a special type of light-harvesting devices because, in addition to electronic mechanisms, the presence of moving ionic species is supposed to modify current-voltage curves.Hysteresis and switchable photovoltaic characteristics have been connected to the kineticsof ion migration but the nature of the specific ionic mechanism (or mechanisms) able toexplain the operation distortions is still poorly understood. The localrearrangement of ions at the electrode interfaces gives rise to commonly observed capacitive effects.Here, we explore charging transients in response to step voltage stimuli using thick MAPbI3 samples deposited onto interdigitated metallic electrodes,and observe how the charging is governed by the local imbalance in the vicinity of the outer interfaces. Charging transients measures in the dark in the absence of direct current areconnected to the responseof a double-layer structure at the interface withthe non-reacting contacts. It is observed that ionic charging, with a typical response time of 10-100 s, isa local effect confined near the electrode.