Optically Activated Delayed Fluorescence.

ABSTRACT: We harness the photophysics of few-atom silver nanoclusters to create the first fluorophores capable of optically activated delayed fluorescence (OADF). In analogy with thermally activated delayed fluorescence, often resulting from oxygen- or collision-activated reverse intersystem crossing from triplet levels, this optically controllable/reactivated visible emission occurs with the same 2.2 ns fluorescence lifetime as that produced with primary excitation alone but is excited with near-infrared light from either of two distinct, long-lived photopopulated dark states. In addition to faster ground-state recovery under long-wavelength co-illumination, this "repumped" visible fluorescence occurs many microsceconds after visible excitation and only when gated by secondary near-IR excitation of

SUBMITTER: Fleischer BC 

PROVIDER: S-EPMC6056314 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature