Exciton Coherence in CsPbBr3 Nanocrystals is Bounded by Phonon-Mediated Bright-Triplet Relaxation
Year: 2026
Type: preprint
Abstract: Scalable sources of indistinguishable single photons or entangled photon pairs are fundamental to many quantum photonic technologies. Colloidal lead halide perovskite nanocrystals are promising such sources, but their exciton coherent properties are not fully understood. We show that in single CsPbBr3 nanocrystals at 4 K, acoustic phonon-mediated exciton fine structure relaxation (EFSR) drives leakage of population between the bright exciton triplet states, competing with the radiative lifetime. The leakage pathway reaches 0.64 $\pm$ 0.04 of the radiative rate, bounding state coherence to 0.81 times the transform limit at 4 K. This pathway is intrinsic to the nanocrystal, not its environment, making it a tractable target for materials and device design. We identify fine structure and acoustic phonon engineering as effective intrinsic routes to higher coherence in perovskite quantum light sources.
Source: arXiv (Cornell University)
Institutions: Massachusetts Institute of Technology, Lund University
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
Funders: National Science Foundation, U.S. Department of Energy, Center for Hybrid Organic Inorganic Semiconductors for Energy, European Commission, Office of Science, HORIZON EUROPE Framework Programme, Office of Naval Research, Division of Materials Research, Basic Energy Sciences, Army Research Office
OpenAlex ID: W7212063788