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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 33: Perovskite and photovoltaics II (joint session HL/CPP)
CPP 33.7: Talk
Wednesday, March 29, 2023, 11:45–12:00, JAN 0027
Coherent Phonons in Halide Perovskite Nanocrystals — •Julian Georg Mann1, Fei He1, Quinten Akkerman1, Tushar Debnath2, and Jochen Feldmann1 — 1Chair for Photonics and Optoelectronics, Nano-Institute Munich and Department of Physics, Ludwig-Maximilians-Universität (LMU), Königinstr. 10, 80539 Munich, Germany — 2Centre for Nanotechnology, Indian Institute of Technology Guwahati, Guwahati-781039
Halide perovskite nanocrystals are gaining increasing attention in contemporary research due to their promising performance in both light-emitting and solar technologies. We recently showed that photoexcitation of halide-perovskite nanocrystals with ultrashort laser pulses produces coherent phonons (Nat. Comm. 12, 2629 (2021)). We report femtosecond pump-probe spectroscopy studies on the formation and dynamics of coherent phonons in formamidine lead-halide (FAPbX3) nanocrystals in terms of higher harmonic vibrational modes. In addition, we investigate the dynamics of vibrational wave packets in spherical Cs2AgBiBr6 double perovskite nanocrystals. Here, we observe that optically launched vibrational wave-packets alter spectral positions of excitonic resonances or oscillator strength of particular electronic transitions. Our results show that electron-phonon couplings (polaronic effects) need to be considered to fully understand the optoelectronic properties of halide-perovskite semiconductors.