Temperature-Dependent Phase Stable Hybrid Halide Perovskite Films by Chemical Vapor Deposition

Methylammonium lead iodide (MAPbI_3–xCl_x) thin films were synthesized using chemical vapor deposition. Temperature-dependent grazing incidence synchrotron-based X-ray diffraction measurements confirm that the structure of MAPbI_3–xCl_x, where Cl acts more like a dopant, remains throughout in the tetragonal phase in the temperature range of 20–300 K. These studies are further correlated with temperature-dependent photoluminescence (PL) studies. The PL peak energy monotonically increases with temperature, suggestive of a single-phase behavior. Resistance measurements conducted as a function of temperature show an absence of inflection points, suggesting uniformity in its phase. Between 200 and 325 K, the resistance remains a constant.