Strong plasmonic enhancement of biexciton emission: controlled coupling of a single quantum dot to a gold nanocone antenna

TL;DR

This study demonstrates that precisely positioning quantum dots near gold nanocone antennas significantly boosts biexciton emission efficiency, overcoming non-radiative decay channels and advancing nano-optics applications.

Contribution

The paper introduces a method for controlled coupling of quantum dots to gold nanocone antennas, achieving unprecedented enhancement of multiexcitonic emission.

Findings

Radiative decay rates of monoexcitons and biexcitons increased by over 100 times.

Quantum efficiencies reached 60% for monoexcitons and 70% for biexcitons.

Numerical calculations agree well with experimental results.

Abstract

Multiexcitonic transitions and emission of several photons per excitation comprise a very attractive feature of semiconductor quantum dots for optoelectronics applications. However, these higher-order radiative processes are usually quenched in colloidal quantum dots by Auger and other non-radiative decay channels. To increase the multiexcitonic quantum efficiency, several groups have explored plasmonic enhancement, so far with moderate results. By controlled positioning of individual quantum dots in the near field of gold nanocone antennas, we enhance the radiative decay rates of monoexcitons and biexcitons by 109 and 100 folds at quantum efficiencies of 60% and 70%, respectively, in very good agreement with the outcome of numerical calculations. We discuss the implications of our work for future fundamental and applied research in nano-optics.