Prof. Dr. R. Tuğrul Senger on January 31, 2024 at 15:30 in SA-240


Prof. Dr. R. Tuğrul Senger
Department of Physics, İzmir Institute of Technology

“Polaronic Excitons in Lead Halide Perovskites”

Hybrid organic–inorganic lead halide perovskites are promising materials for photovoltaic and optoelectronic applications. In this talk, I will present temperature-dependent diffusion characteristics of photogenerated carriers in single-crystal microstructures of methylammonium lead iodide/bromide (MAPbI3 and MAPbBr3) as obtained by using scanning photocurrent microscopy. We observe an interesting abrupt enhancement in carrier diffusion lengths during the tetragonal to orthorhombic phase transitions of these crystals. Specifically, at 80 K, the carrier diffusion length reaches a significant value of 200±50 μm for MAPbI3. We attribute this phenomenon to the efficient formation and diffusion of free excitons within the low-temperature phase of these materials. Regarding the strong electron-phonon coupling in hybrid halide perovskites, we propose dominance of polaronic-excitons as a potential mechanism for the observed increase in carrier diffusion lengths at lower temperature.

Date: January 31, 2024 Wednesday
Time: 15:30
Place: SA-240

All interested are cordially invited.