Zernike seminar: Artem Bakulin - IR spectroscopy of perovskites – carrier cooling, electron-phonon coupling, and charge trapping dynamics

Hot carriers in metal-halide perovskites (MHPs) present a foundation for understanding carrier-phonon coupling in the materials as well as the prospective development of high-performance devices and hot-carrier photovoltaics. While the carrier population dynamics during the carrier cooling have been scrutinized by many studies, the evolution of the hot carrier properties, including carrier energetics, mobility, and trapping remains largely unexplored. Here we introduce novel ultrafast visible pump–infrared push spectroscopy with different types of probes including IR, terahertz and photocurrent to monitor the real-time conductivity dynamics of carriers in different types of perovskite based materials and devices. Our results reveal the sensitivity of electron-phonon coupling and hot phonon bottleneck to material properties. The also highlight the importance of localized lattice heating toward the hot carrier mobility and effect of surface passivation on charge extraction.