Single-Particle Insights into Circularly Polarized Emission from Chiral Ligand-Tailored Perovskite Nanocrystals.

Abstract

Chiral ligand-functionalized perovskite nanocrystals (NCs) are promising sources of circularly polarized light, yet their intrinsic emissive behavior is often blurred by ensemble averaging, limiting mechanistic insights into chirality transfer. Here, by resolving individual emitters, single-NC spectroscopy unveils heterogeneity that complements ensemble measurements. Only a minority (∼22.2%) of NCs exhibit detectable chiroptical response, whereas rare emitters display circular polarization degrees approaching ∼48.0% while maintaining excellent single-photon purity of ∼95.0%. By disentangling fluorescence blinking and inhomogeneous broadening, we reveal that ligand chirality imprints distinct fingerprints on excitonic emission, including static energy splitting and dynamic asymmetry in radiative decay rates. These results provide direct evidence of the coupling between molecular chirality and NC band-edge emission states. Our findings underscore single-particle spectroscopy as an effective probe to identify emitter-specific behavior and offer fundamental insights for advancing chiral perovskite NCs toward efficient chiral quantum light sources.