Synthesis and Theoretical–Experimental Characterization of BiOBr: The Role of Oxygen and Halide Vacancies on the Optoelectric Properties of this Bismuth Oxyhalide

In the present work, we report the synthesis and theoretical–experimental characterization of BiOBr employing X-ray diffraction, Raman spectroscopy, conductivity measurements, and first principles calculations based on Functional Density Theory (DFT). This work aims to elaborate on the impact of optoelectronic properties by the presence of oxygen and halogen vacancies in the bismuth oxybromide. To our knowledge, this is the first detailed study of the optical properties of reduced BiOBr. The results included in this work could explain, for the first time, the peculiarities of the changes observed in the dielectric function (real and imaginary part) as well as the related quantities such as absorption coefficient, refractive index, reflectivity and extinction coefficient. It was also possible to determine the vibrational modes of the stoichiometric system using in combination Raman and DFT calculations.