Visualization of dynamic polaronic strain fields in shape-tuned nanocrystalline CsPbBr3 perovskites

Lead halide perovskites (LHPs) have shown superior performance in various electro-optic applications, such as light-emitting diodes, and photovoltaic cells, which depend on the interconversion of photons and mobile charge carriers. The charge carrier becomes thus dressed by a local lattice deformation, forming a polaron quasiparticle. Because of the weak-to-intermediate electron-phonon interaction in LHPs, large polarons develop, with the lattice distortion spanning over multiple lattice constants, i.e., a few nanometres. Our target is to identify the crystallographic phase, coordination chemistry, local octahedral tilting, disorder, etc. on illuminated CsPbBr3 nanocrystals with synthetically tuned morphologies of cubes, hexagon and polygons. For the development of the relation between particle shape and corresponding polaron, we have to performed temperature dependent wide angle x-ray scattering with and without applying femtosecond pulsed laser.