Muon Studies of Ion Diffusion in Single-Crystal Photovoltaic Materials

In recent years, the family of lead halide perovskite materials (e.g. MAPbI3) has attracted substantial interest due to their unique combination of properties and potential solar cell, light-emitting diode, and laser applications. One of the issues with these materials is to keep high efficiency during operation i.e. life-time problems. One of the main reasons behind such degradation has been identified as ion-diffusion causing inhomogeneities in the chemical composition, especially at surfaces and interfaces within the device. This proposed project aims to study the true intrinsic Iodine and Bromine ion diffusion process in high-quality single crystalline samples of MAPbI3 and MAPPbBr3 using our own developed muon spin rotation (muSR) technique. The study is an initial study on the course towards future in situ / in operando studies using the same (and similar) single crystal samples.