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HL: Fachverband Halbleiterphysik
HL 35: Perovskite and photovoltaics II (joint session HL/CPP)
HL 35.3: Vortrag
Dienstag, 17. März 2020, 14:30–14:45, POT 251
Ultrafast vibrational dynamics in lead halide perovskites — •Ajay Jha1, Hong-Guang Duan1, Vandana Tiwari1, Golibjon Berdiyorov2, Alexey Akimov3, Pabitra Nayak4, Zheng Li1, Hernry Snaith4, Michael Thorwart5, Mohamed Madjet2, and R. J. Dwayne Miller1,6 — 1MPSD, Hamburg — 2Qatar Environment & Energy Research Institute, Doha — 3Department of Chemistry, State University of New York — 4Department of Physics, University of Oxford — 5I. Institut für Theoretische Physik, University of Hamburg — 6Departments of Chemistry and Physics, University of Tornoto
Hybrid organic-inorganic perovskites have gathered much attention owing to their unprecedented success in photovoltaics. To unravel the secrets to this success, we have studied the ultrafast dynamics of lead halide perovskites using heterodyne-detected transient grating and 2D spectroscopy in thin films for tetragonal (room temperature) and orthorhombic phases (T = 20 K). Our measurements capture the different ultrafast exciton dynamics in two phases of perovskite. In addition, we distinctly observe the ground and excited state vibrational modes corresponding to organic and inorganic sub-lattices in two phases. The interplay of strongly coupled dominant vibrational modes to ultrafast carrier generation process will be discussed. To rationalize our observations, we have employed density functional theory (DFT) predicting changes in the vibrational observations highlighting the importance of interaction between organic cation and inorganic sub-lattice in stabilization of charges upon photoexcitation.