Nonradiative processes significantly impact the efficiency of semiconductor nanocrystal (NC)-based devices. This paper focuses on hot exciton cooling, the nonradiative relaxation of a highly excited electron/hole pair to form a band-edge exciton. Using an atomistic approach, the authors simulate cooling in CdSe NCs, finding that cooling occurs on ~30 fs timescales, circumventing the phonon bottleneck through a cascade of multiphonon-mediated relaxation events. The study also identifies NC handles for tuning the cooling timescale.

Dipti Jasrasaria, Eran Rabani