Halide Perovskites

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Webinar "Shining light on phase-segregation in mixed-halide Perovskites" on July 4th

par qhuy -

Mixed-halide perovskites have been found to date the most promising materials in the family of hybrid perovskite materials for photovoltaic applications. However, these advanced perovskite materials may undergo phase-segregation under continuous light illumination due to halide ion migration, affecting their optoelectronic properties.

In this contribution, we report such phase segregation effect in triple-cation based mixed-halide (I, Br) hybrid perovskite film when subjected to photo-excitation. We present here the highlight of relationship between photo-induced phase segregation and unusual increase in carrier lifetime in mixed halide perovskite under illumination (> 1 μs). The halide ion migration leads to the formation of smaller-bandgap iodide-rich and larger-bandgap bromide-rich domains in the perovskite film. Interestingly, these photoinduced changes are fully reversible and thermally activated when the excitation power is turned off. A significant difference in activation energies for halide ion migration is observed during phase segregation and recovery process.

Additionally, we have addressed the key issue of such as, are point defects favorable to control materials’ properties ? Do structural defects play a role in the photo-induced phase segregation (halide mobility, kinetics of phase separation) ? Therefore, we introduced on purpose different defect concentrations into perovskite films with 1 MeV proton ion irradiation. Here, we will present the impact of radiation-defects on photo-induced phase segregation and radiation-stability of halide perovskites film against 1 MeV proton using time-resolved photoluminescence (PL) studies.