Unraveling temperature-dependent structural instabilities in halide double perovskite nanocrystals

The development of colloidal nanocrystals as next-generation semiconductors relies heavily on understanding their structure with atomic-level precision, which is critical for interpreting and predicting the interaction between charge carriers and their lattice. In particular, halide perovskites are characterized by highly deformable octahedra frameworks, which makes conventional pictures based on phase diagrams inadequate to account for their structural subtleties; halide double perovskites with alternating octahedral units add one further layer of complexity. With the present proposal, we plan a combined XAS/TS approach to characterize the structural response of halide perovskite nanocrystals in a wide temperature range relevant to optoelectronic applications and provide a comprehensive description of their local structure and dynamics across different length scales.