This study utilizes transient absorption in the mid-infrared region to monitor electron signatures in the conduction bands of perovskite materials, without interference from other dynamical species. The recombination and trapping processes of excited carriers are monitored within 4000-6000 nm (2500–1666 cm⁻¹). Iodide-based films show a greater tendency to trap excited electrons compared to bromide-based films, a process identified by mid-infrared emission. Various parameters, including film composition, excitation dependence, and probing wavelength, were tested. This research establishes mid-infrared transient absorption as a tool for studying trapping processes in perovskite films, both qualitatively and quantitatively.

Ahmed M. El-Zohry, Bekir Turedi, Abdullah Alsalloum, Partha Maity, Osman M. Bakr, Boon S. Ooi, Omar F. Mohammed