Inhibited spontaneous emission of quantum dots weakly coupled to off resonant silver nanoplatelets and silver nanowires

TL;DR

This paper demonstrates that coupling quantum dots to silver nanostructures with off-resonant plasmonic modes can inhibit their spontaneous emission rate, providing insights into emission control outside resonant conditions.

Contribution

It shows for the first time that off-resonant silver nanostructures can suppress quantum dot emission rates through weak coupling, expanding the understanding of emission modulation mechanisms.

Findings

Quantum dots coupled to silver nanostructures exhibit suppressed emission rates.

Off-resonant plasmonic modes can inhibit spontaneous emission.

Time-resolved photoluminescence confirms emission suppression.

Abstract

Spontaneous emission (SE) rate of any light emitters directly scales with the locally available modes for photons. The emission rate can be modified, by changing the dielectric environment of light emitters. Generally cavities with modes in resonance to light emission frequency, are used to amplify the light emission rate. The Fermi golden rule predicts that if the cavity modes are offresonant to the emission frequency, then the SE rate is suppressed. In this study, we demonstrate that the SE of colloidal alloyed quantum dots is inhibited by coupling them to chemically synthesized Silver nanowires and Silver nanoplatelet systems. The silver nanoplatelet and silver nanowire plasmonic resonance modes are in ultraviolet and infrared regions of the electromagnetic spectrum. The quantum dots emit in visible region of light. This off-resonant weak coupling of emitters and cavities results in emission rate suppression and is quantified by time resolved photoluminescence (TRPL) measurements. TRPL decay profiles show that the emission rate can be suppressed by coupling self assembled quantum dot monolayers to a single silver nanoplatelet and a single silver nanowire respectively.