Dark and Bright Excitons in Halide Perovskite Nanoplatelets.

ABSTRACT: Semiconductor nanoplatelets (NPLs), with their large exciton binding energy, narrow photoluminescence (PL), and absence of dielectric screening for photons emitted normal to the NPL surface, could be expected to become the fastest luminophores amongst all colloidal nanostructures. However, super-fast emission is suppressed by a dark (optically passive) exciton ground state, substantially split from a higher-lying bright (optically active) state. Here, the exciton fine structure in 2-8 monolayer (ML) thick Cs_{n - 1} Pb_n Br_{3n + 1} NPLs is revealed by merging temperature-resolved PL spectra and time-resolved PL decay with an effective mass model taking quantum confinement and dielectric confinement anisotropy into account. This approach exposes a thickness-depend

SUBMITTER: Gramlich M 

PROVIDER: S-EPMC8844578 | biostudies-literature | 2022 Feb

REPOSITORIES: biostudies-literature