PeroVIB · Control of Vibronic Coupling in Hybrid Perovskites and its Impact on Charge Transport

Owing to the “soft” nature of perovskite lattice, structural deformations (vibrations) play a crucial role in modulating the electronic dynamics of perovskites. In fact, one may engineer the key optoelectronic properties of this class of materials by tuning the coupling strength between photoexcited charge carriers and lattice phonons. Experimental realization of such vibronic coupling in the compositional space of perovskites remains so far unexplored. Herein through this project, I aim to identify the crucial vibrational modes of hybrid perovskites (of various compositions and dimensions) that influence the electronic dynamics and charge transport in real electronic devices of them. To address this fundamental problem, I plan to develop double-resonant excitation (infrared pre-excitation prior to electronic excitation) based ""Vibrationally Promoted Electronic Resonance"" spectroscopic technique that will give a direct access to monitor the vibrational dynamics of organic and inorganic sub-lattice in the electronically excited state of the hybrid perovskites. This technique is specifically proposed here for probing the vibronic coupling of these soft materials with high mode-selectivity. We will further explore pump-push photocurrent spectroscopy on real functional electronic devices of those perovskites to identify the role of structural fluctuations in modulating the charge transport efficiency. This unique hybrid spectroscopic approach will provide wealth of information from fundamental structural dynamics to device performance