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HL: Fachverband Halbleiterphysik
HL 46: Ultra-fast Phenomena II
HL 46.1: Vortrag
Donnerstag, 12. März 2026, 15:00–15:15, POT/0051
Ultrafast study of out-of-plane charge carrier diffusion in perovskite thin films via pump-probe sSNOM — •Daniel Sandner1, Branden Esses2, Zhao Yang3, Kai Zhu3, Joseph Berry2,3, Hristo Iglev1, and Markus Raschke2 — 1Laser- and X-ray physics E11, TU Munich — 2CU Boulder — 3NREL
Despite substantial evidence for polaron formation in lead halide perovskites (LHPs), which exhibit excellent photovoltaic performance, the role of polarons in transport remains unclear. We've measured diffusion with high spatial resolution by monitoring the carrier density at the top of a thin film via the tip-localized response in pump-probe mIR-sSNOM, while exciting the sample from below. Due to the small penetration depth of the pump beam, most electrons and holes are initially located at the bottom of the perovskite layer. Consistent with previous studies, we find local variations in the diffusion coefficient. To link transport and local structure, we employ a vibrational mode as an indicator of lattice stiffness and polaron formation [JACS 2024, 146(29), 19852-19862].
Keywords: Perovskite; Polaron; Diffusion; Near-field Microscopy; SNOM