Non-radiative decay of a dipole emitter close to a metallic nanoparticle: Importance of higher-order multipole contributions

TL;DR

This paper investigates how higher-order multipoles significantly influence non-radiative decay rates of a dipole emitter near a metallic nanoparticle, revealing limitations of dipole approximations and improvements with size-corrected dielectric functions.

Contribution

It demonstrates the substantial role of higher-order multipoles in non-radiative decay and compares different computational methods for accuracy.

Findings

Higher-order multipoles contribute 50-101% to non-radiative rates.

Dipole approximation overestimates quantum yield.

Size-corrected dielectric functions reduce non-radiative rates near plasmon resonance.

Abstract

The contribution of higher-order multipoles to radiative and non-radiative decay of a single dipole emitter close to a spherical metallic nanoparticle is re-examined. Taking a Ag spherical nanoparticle (AgNP) with the radius of 5 nm as an example, a significant contribution (between 50% and 101% of the total value) of higher-order multipoles to non-radiative rates is found even at the emitter distance of 5 nm from the AgNP surface. On the other hand, the higher-order multipole contribution to radiative rates is negligible. Consequently, a dipole-dipole approximation can yield only an upper bound on the apparent quantum yield. In contrast, the non-radiative rates calculated with the quasistatic Gersten and Nitzan method are found to be in much better agreement with exact electrodynamic results. Finally, the size corrected metal dielectric function is shown to decrease the non-radiative rates near the dipolar surface plasmon resonance.