Observation of Three-Photon Cascaded Emission from Triexcitons in Giant CsPbBr<sub>3</sub> Quantum Dots at Room Temperature.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 39400074.
- Also identified by DOI 10.1021/acs.nanolett.4c03096 and PMC identifier 11503816.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Colloidal semiconductor nanocrystals have long been considered a promising source of time-correlated and entangled photons via the cascaded emission of multiexcitonic states. The spectroscopy of such cascaded emission, however, is hindered by efficient nonradiative Auger-Meitner decay, rendering multiexcitonic states nonemissive. Here we present room-temperature heralded spectroscopy of three-photon cascades from triexcitons in giant CsPbBr<sub>3</sub> nanocrystals. We show that this system exhibits second- and third-order correlation function values, g<sup>(2)</sup>(0) and g<sup>(3)</sup>(0,0), close to unity, identifying very weak binding of both biexcitons and triexcitons. Combining fluorescence lifetime analysis, photon statistics, and spectroscopy, we can readily identify emission from higher multiexcitonic states. We use this to verify emission from a single emitter despite high emission quantum yields of multiply excited states and comparable emission lifetimes of singly and multiply excited states. Finally, we present potential pathways toward control of the photon number statistics of multiexcitonic emission cascades.