Fluorescence quenching near small metal nanoparticles

TL;DR

This paper presents a quantum-mechanical model for fluorescence quenching near small metal nanoparticles, revealing that quantum effects significantly influence energy transfer rates and differ from classical predictions.

Contribution

It introduces a microscopic quantum model that accounts for non-local and quantum-size effects in fluorescence near metal nanoparticles, improving upon semiclassical theories.

Findings

Quantum effects enhance dissipation in metal nanoparticles.

Energy transfer rates depend weakly on distance, deviating from classical $d^{-4}$ behavior.

Quantum-size effects are significant at nanometer scales.

Abstract

We develop a microscopic model for fluorescence of a molecule (or semiconductor quantum dot) near a small metal nanoparticle. When a molecule is situated close to metal surface, its fluorescence is quenched due to energy transfer to the metal. We perform quantum-mechanical calculations of energy transfer rates for nanometer-sized Au nanoparticles and find that non-local and quantum-size effects significantly enhance dissipation in metal as compared to those predicted by semiclassical electromagnetic models. However, the dependence of transfer rates on molecule's distance to metal nanoparticle surface, $d$, is significantly weaker than the $d^{-4}$ behavior for flat metal surface with a sharp boundary predicted by previous calculations within random phase approximation.