Direct Observation of Ultrafast Lattice Distortions during Exciton-Polaron Formation in Lead Halide Perovskite Nanocrystals.

ABSTRACT: The microscopic origin of slow hot-carrier cooling in lead halide perovskites remains debated and has direct implications for applications. Slow hot-carrier cooling of several picoseconds has been attributed to either polaron formation or a hot-phonon bottleneck effect at high excited carrier densities (>10¹⁸ cm^-3). These effects cannot be unambiguously disentangled with optical experiments alone. However, they can be distinguished by direct observations of ultrafast lattice dynamics, as these effects are expected to create qualitatively distinct fingerprints. To this end, we employ femtosecond electron diffraction and directly measure the sub-picosecond lattice dynamics of weakly confined CsPbBr₃ nanocrystals following above-gap photoexcitation. While we d

SUBMITTER: Seiler H 

PROVIDER: S-EPMC9933605 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature