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HL: Fachverband Halbleiterphysik
HL 42: Perovskite and Photovoltaics II (joint session HL/KFM)
HL 42.9: Talk
Thursday, March 21, 2024, 11:45–12:00, EW 203
Photon echo spectroscopy of CsPbI3 nanocrystals — Artur V. Trifonov1,2, •Mario Alex Hollberg1, Stefan Grisard1, Elena V. Kolobkova3,4, Maria S. Kuznetsov2, Mikhail O. Nestoklon1, Jan Kaspari5, Doris Reiter5, Dmitri R. Yakovlev1,6, Manfred Bayer1, and Ilya A. Akimov1 — 1Experimentelle Physik 2, Technische Universität Dortmund — 2St. Petersburg, Russia — 3St. Petersburg, Russia — 4St. Petersburg, Russia — 5Condensed Matter Theory, Technische Universität Dortmund — 6St. Petersburg, Russia
All-inorganic halide perovskite nanocrystals hold potential for future optoelectronic technologies. One of the paths to fully unlock their capabilities, is a deeper understanding of coherent exciton dynamics in these materials. In this work, we investigated a caesium lead tri-iodide (CsPbI3) nanocrystal ensemble using time-resolved photon echo spectroscopy at cryogenic temperatures (1.5 K). We observed a long exciton lifetime T1 of about 1 ns and an exciton coherence time T2 of up to approximately 300 ps. The initial tens of picoseconds in the photon echo decay exhibited oscillatory behavior with two most pronounced frequencies of 3.2 meV and 5.1 meV, which we attribute to the interaction between excitons and optical phonons. The exciton fine structure manifests itself at lower oscillation frequencies of 0.2 meV and 1.1 meV.
Keywords: Exciton; Photon Echo; Perovskite nanocrystal ensemble; Coherent optical phonons; Exciton fine structure