Revealing and Manipulating Hidden Fine-Structure Coherence of Bright Excitons in CsPbI<sub>3</sub> Perovskite Quantum Dots.
basic_science · Level V
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- Record sourced from PubMed, PMID 39480460.
- Also identified by DOI 10.1021/acs.nanolett.4c04772.
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Abstract
Observation and understanding of fine-structure splitting of bright excitons in lead halide perovskite quantum dots (QDs) are crucial to their emerging applications in quantum light sources and exciton coherence manipulation. Recent studies demonstrate that ensemble-level polarization-resolved transient absorption spectroscopy can reveal the quantum beats arising from the coherence between two fine-structure levels. Here we report the observation of an extra fine-structure quantum coherence hidden in previous studies by using cryo-magnetic quantum beat spectroscopy. In ∼6 nm CsPbI<sub>3</sub> QDs, two splitting energies of 0.25 and 1.20 meV were observed at 1.7 K, which gradually increased to 0.74 and 1.55 meV, respectively, when a longitudinal magnetic field up to 7 T was applied. The field dependence allowed us to extract two distinct nominal Landé <i>g</i>-factors corresponding to QDs with different orientations with respect to the external field.