Speaker
Description
Lattice dynamics play a central role in determining the optoelectronic performance and stability of metal halide perovskites. In lead-free vacancy-ordered Cs₂SnBr₆, understanding phonon behavior and electron–phonon interactions is essential for assessing its suitability for durable optoelectronic applications. Here, we investigate the vibrational properties of Cs₂SnBr₆ using inelastic neutron scattering (INS) on the MERLIN spectrometer at ISIS, complemented by X-ray absorption spectroscopy (XAS) at the IPE beamline (LNLS) to probe local structural order. The INS measurements reveal well-defined, temperature-stable phonon features over a wide energy range, indicating a rigid, weakly anharmonic lattice. A low-temperature enhancement of low-energy spectral weight suggests electron–phonon–coupled excitations, while the absence of structural anomalies confirms robust lattice stability. These results provide new insight into phonon-mediated processes in lead-free halide perovskites and support the potential of Cs₂SnBr₆ for stable optoelectronic devices.