Dresden 2020 – wissenschaftliches Programm
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HL 76.25: Poster
Donnerstag, 19. März 2020, 15:00–17:30, P2/4OG
Surface charge-carrier dynamics of CsPbBr3 inorganic perovskite — •Felix Trunk, Janek Rieger, Thomas Fauster, and Daniel Niesner — Lehrstuhl für Festkörperphysik, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Staudtstr. 7, D-91058 Erlangen, Germany
Several models have been proposed to understand the outstanding long lifetimes of charge carriers in lead-halide perovskites. Amongst others, there is an ongoing debate about the role of the organic ion on the charge-carrier cooling. We investigated the femto- to picosecond dynamics of conduction-band electrons at the surface of the purely inorganic perovskite CsPbBr3.
Time-resolved bichromatic two-photon photoelectron spectroscopy with femtosecond time-resolution was carried out on epitaxially grown films with well-defined crystalline surfaces. The position of the conduction-band minimum indicates that our samples are intrinsic. Therefore, the carrier dynamics is dominated by electron-phonon scattering rather than electron-electron scattering.
In a systematic study, we could identify three different time regimes. After the initial cooling we can detect a second time constant before the charge carriers recombine.
The poster will focus on a comparison of carrier dynamics for different sample temperatures and thicknesses. From the latter we can distinguish carrier recombination at the surface from their diffusion into the bulk.