Doping Effects and Charge-Transfer Dynamics at Hybrid Perovskite/Graphene Interfaces

In this work doping effects and charge transfer processes at the perovskite/graphene interface in the dark and under illumination are investigated. Hall effect, field effect, and surface photovoltage measurements suggest that hybrid perovskite layers induce strong n-type doping of graphene after annealing at low temperature (330 K) in vacuum. It is found that the observed photoinduced changes in the electronic properties of graphene, functionalized by a hybrid organic-inorganic perovskite layer, are caused by two independent mechanisms with different time scales: (i) a fast collection of photogenerated holes by graphene from the perovskite layer and (ii) a slow ion rearrangement in the perovskite lattice at the perovskite/graphene interface. The observed annealing-induced n-type and photoinduced p-type doping effects allow to reversibly switch the type of conduction of the perovskite/graphene system.