Berlin 2024 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 31: Perovskite and Photovoltaics III (joint session HL/KFM)
KFM 31.10: Vortrag
Freitag, 22. März 2024, 12:00–12:15, EW 203
Nanospectroscopy and ultrafast out-of-plane carrier dynamics in metal halide perovskites — •Martin Zizlsperger1, Svenja Nerreter1, Qimu Yuan2, Kilian B. Lohmann2, Fabian Sandner1, Felix Schiegl1, Christian Meineke1, Yaroslav Gerasimenko1, Laura M. Herz2, Thomas Siday1,2, Markus A. Huber1, Michael B. Johnston2, and Rupert Huber1 — 1Department of Physics and Regensburg Center for Ultrafast Nanoscopy (RUN), University of Regensburg, 93040 Regensburg, Germany — 2Department of Physics, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
The high efficiencies of metal halide perovskite solar cells have been associated with effective charge-carrier diffusion. Still, the characteristic nanograins and crystallographic disorder entailed in perovskite films hindered unraveling details of the vertical transport, calling for simultaneous experimental access to chemical composition, structural phase and ultrafast out-of-plane dynamics. Here, we promote depth-sensitive terahertz near-field nanospectroscopy to extreme subcycle time scales. In FA0.83Cs0.17Pb(I1−xClx)3 films, we discern domains of the α-phase from δ-phase and PbI2 nano-islands. Based on deep-subcycle time shifts of the scattered terahertz waveform after photoexcitation, we access the single-grain vertical diffusion. Despite topographic irregularities, diffusion is surprisingly homogeneous on sub-micrometer length scales, only varying between mesoscopic regions. Our approach linking nano-morphology with carrier dynamics may benefit all future optoelectronic devices using nanocrystalline materials.
Keywords: Near-field microscopy; THz-spectroscopy; Ultrafast; Metal halide perovskites; Diffusion