Unraveling the activation energy of halide migration in compressed mixed-halide perovskites

Mixed-halide perovskites suffer from phase segregation when continuously illuminated resulting in halide-rich domains with different bandgaps, hampering their applications in real devices. Interestingly, this process is fully reversible in the dark. Halide perovskites are very soft, contrary to other semiconductors, and their properties are strongly correlated to their crystal structure. Mild pressures have been used to shift the compositional threshold for phase segregation. However, little is known about the origin of this shift and the activation energy for halide migration as a function of pressure is not yet reported. In this proposal, we will use high-pressure time-resolved (seconds to minutes) X-ray under segregation conditions to obtain the the activation energy of the segregation (in light) and recovery (in dark) in the range of 0 ₋ 0.45 GPa.