title: Energy Transfer Sensitization of Luminescent Gold Nanoclusters: More than Just the Classical Förster Mechanism.
abstract: Luminescent gold nanocrystals (AuNCs) are a recently-developed material with potential optic, electronic and biological applications. They also demonstrate energy transfer (ET) acceptor/sensitization properties which have been ascribed to Förster resonance energy transfer (FRET) and, to a lesser extent, nanosurface energy transfer (NSET). Here, we investigate AuNC acceptor interactions with three structurally/functionally-distinct donor classes including organic dyes, metal chelates and semiconductor quantum dots (QDs). Donor quenching was observed for every donor-acceptor pair although AuNC sensitization was only observed from metal-chelates and QDs. FRET theory dramatically underestimated the observed energy transfer while NSET-based damping models provided better fits but could not reproduce the experimental data. We consider additional factors including AuNC magnetic dipoles, density of excited-states, dephasing time, and enhanced intersystem crossing that can also influence ET. Cumulatively, data suggests that AuNC sensitization is not by classical FRET or NSET and we provide a simplified distance-independent ET model to fit such experimental data.
authors: Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, DC 20375, USA.|Sotera Defense Solutions, Inc. Columbia, MD 21046, USA.
authors: Eunkeu
authors: E
authors: Oh
authors: Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, DC 20375, USA.
authors: Alan L
authors: AL
authors: Huston
authors: Center for Computational Material Science Code 6390, U.S. Naval Research Laboratory, Washington, DC 20375, USA.
authors: Andrew
authors: A
authors: Shabaev
authors: Center for Computational Material Science Code 6390, U.S. Naval Research Laboratory, Washington, DC 20375, USA.
authors: Alexander
authors: A
authors: Efros
authors: Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, DC 20375, USA.
authors: Marc
authors: M
authors: Currie
authors: Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, DC 20375, USA.|Sotera Defense Solutions, Inc. Columbia, MD 21046, USA.
authors: Kimihiro
authors: K
authors: Susumu
authors: Materials and Sensors Branch Code 6361, U.S. Naval Research Laboratory, Washington, DC 20375, USA.
authors: Konrad
authors: K
authors: Bussmann
authors: Multifunctional Materials Code 6351, U.S. Naval Research Laboratory, Washington, DC 20375, USA.
authors: Ramasis
authors: R
authors: Goswami
authors: Optical Sciences Division Code 5600, U.S. Naval Research Laboratory, Washington, DC 20375, USA.
authors: Fredrik K
authors: FK
authors: Fatemi
authors: Center for Bio/Molecular Science and Engineering Code 6900, U.S. Naval Research Laboratory, Washington, DC 20375, USA.
authors: Igor L
authors: IL
authors: Medintz