Journal Article perovskite solar cells THz spectroscopy charge-carrier recombination Research Support, Non-U.S. Gov't SnF2 cation disorder cesium chalcogenides charge diffusion length charge-carrier mobility charge-carrier transport colloids coordination crystallization kinetics distributed feedback lasers doping evaporation halide segregation hybrid perovskite photovoltaics interfacial chemistry long-term stability mixed-cation mixed-halide mixed-halide perovskites nanoimprinting nucleation optical devices perovskite films perovskites phase disorder