This special issue explores the extraordinary luminescence properties of metal halide perovskites. Metal halide perovskites have emerged at the forefront of next-generation, thin-film semiconductors for photovoltaic and light-emitting applications. These materials exhibit remarkable optoelectronic properties such as long charge carrier diffusion lengths and high radiative emission efficiencies, which are unexpected for low-temperature, solution-processed semiconductors. Despite impressive technological advancements in device efficiency, a fundamental understanding of perovskite photophysics and photochemistry is still lagging behind. In particular, perovskites often suffer from unpredictable variations in non-radiative recombination and a range of complex dynamic phenomena that remain poorly understood. This issue contains 26 peer-reviewed papers focused on elucidating and further exploring the intricate relationship between luminescence properties and perovskite synthesis, material composition and structure. The issue traces fundamental structure-function relationships on a microscopic level, which serves as a platform to further understand the photophysical processes in composite heterostructures and devices
