Atomic and electronic structure modifications due to bismuth doping in hybrid perovskites

We aim to elucidate the role of Bi3+ as dopant in APbI3 hybrid halide pseudo-perovskites (A = CH3NH3+ (MA) or (CH3)3SO+ (TMSO)). These compounds present different connectivity of [PbI6] octahedra and, accordingly, a different structural dimensionality. This difference affects the electronic levels of the pristine compounds and, consequently, of the doped samples. Heterovalent doping on these perovskites significantly decreases the bandgap and is massively beneficial for electric conductivity. Through XAFS measurements at Pb- and Bi- edges on samples with different Bi doping, we expect to elucidate the role of the local structure in changing the electronic structure and band gap of model compounds for thermoelectrics and photovoltaics.