Phase Distributions and Local Bandgap Energies in Mixed-Halide Perovskite Nanoparticles

Monochromated, aberation-corrected scanning transmission electron microscopes enable the investigation of chemical distribution and optical properties such as the bandgap energy. We conducted valence and core electron energy-loss spectroscopy on nanoparticles made of the inorganic double-halide perovskites CsPb(IxBr1-x)3 (x=0-1) to investigate the distribution of halogen anions as well as Cs and Pb cations inside the nanoparticles and correlated the results with bandgap energy mappings. Changes of the chemical distribution with continuous electron beam irradiation were observed.