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Photo-induced enhancement of lattice fluctuations in metal-halide perovskites.

ABSTRACT: The optoelectronic properties of metal-halide perovskites (MHPs) are affected by lattice fluctuations. Using ultrafast pump-probe spectroscopy, we demonstrate that in state-of-the-art mixed-cation MHPs ultrafast photo-induced bandgap narrowing occurs with a linear to super-linear dependence on the excited carrier density ranging from 10¹⁷ cm^-3 to above 10¹⁸ cm^-3. Time-domain terahertz spectroscopy reveals carrier localization increases with carrier density. Both observations, the anomalous dependence of the bandgap narrowing and the increased carrier localization can be rationalized by photo-induced lattice fluctuations. The magnitude of the photo-induced lattice fluctuations depends on the intrinsic instability of the MHP lattice. Our findings provide insight into ultrafast processes in MHPs following photoexcitation and thus help to develop a concise picture of the ultrafast photophysics of this important class of emerging semiconductors.

SUBMITTER: Wang M

PROVIDER: S-EPMC8866428 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature

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Photo-induced enhancement of lattice fluctuations in metal-halide perovskites.

Wang Mingcong M Gao Yajun Y Wang Kai K Liu Jiang J De Wolf Stefaan S Laquai Frédéric F

Nature communications 20220223 1

The optoelectronic properties of metal-halide perovskites (MHPs) are affected by lattice fluctuations. Using ultrafast pump-probe spectroscopy, we demonstrate that in state-of-the-art mixed-cation MHPs ultrafast photo-induced bandgap narrowing occurs with a linear to super-linear dependence on the excited carrier density ranging from 1017 cm-3 to above 1018 cm-3. Time-domain terahertz spectroscopy reveals carrier localization increases with carrier den ...[more]

PMID: 35197455

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