Monocrystalline halide perovskite nanostructures for optoelectronic applications

Halide perovskites are a promising class of materials for incorporation in optoelectronics with higher efficiency and lower cost. The solution processability of these materials provides unique opportunities for simple nanostructure fabrication. In the first half of the thesis (chapter 2 and 3) we demonstrated a simple technique to fabricate thin halide perovskite single crystals with laterally large dimensions and make microscale devices. Using these devices, we observe the ionic migration in the presence of applied electric field by means of X-ray fluorescence. The photoluminescence of these crystals is enhanced in halide rich region, indicating the effect of ionic migration on the local optical properties of the crystals. In the second half of this thesis we present a method to fabricate vertical nanowires by extrusion of perovskite solution through nanopores of aluminum oxide (AAO) templates. We study the photoluminescence quantum yield and charge carrier recombination in these nanowires. The obtained results in this thesis provide an insight into new methods for fabrication of high quality single crystalline halide perovskite micro- and nanostructures. The fabricated perovskite microcrystals and nanowires are used as simple model systems to study the fundamental properties of halide perovskites by asking questions such as: Which ions are moving in perovskites? How does ionic migration affect the properties of perovskites? What is the potential for improving the surface properties of perovskites by alumina passivation? The answers to these questions expands our understanding of halide perovskite nanostructures and their potentials and limitations for incorporation into future optoelectronic devices