Unveiling the structural evolution of halide double perovskite down to cryogenic temperatures

The development of next-generation semiconductors relies heavily on understanding their structure with atomic-level precision, which is critical for interpreting and predicting the interaction between carriers and their lattice. In particular, halide perovskites are characterized by a highly deformable octahedral framework, which makes conventional phase diagram reconstruction inadequate. Lead-free halide double perovskites (HDPs) are promising alternatives to lead-based semiconductors, addressing toxicity and stability issues. In this proposal, we aim to combine local structural insights from X-ray Absorption Near Edge Structure (XANES) experiments performed down to cryogenic temperatures with X-ray Total Scattering (TS). By reconstructing the interplay between local and average structural features of HPDs and their evolution down to cryogenic temperatures, we aim to establish a comprehensive framework that is currently lacking but essential for advancing HDPs in optoelectronics.