Measurement of the radiative and non-radiative decay rates of single CdSe nanocrystals through controlled modification of their spontaneous emission

TL;DR

This paper introduces a straightforward method to measure radiative and non-radiative decay rates of single CdSe nanocrystals at room temperature by manipulating their proximity to a dielectric interface and analyzing their photoluminescence.

Contribution

It provides a novel single-molecule technique to accurately determine both radiative and non-radiative decay rates and quantum efficiency of CdSe nanocrystals.

Findings

Quantum efficiency of 98% for CdSe nanocrystals.

Direct evidence of the bi-dimensional transition dipole.

Validation of the method at room temperature.

Abstract

We present a simple method to measure the radiative and non-radiative recombination rates of individual fluorescent emitters at room temperature. By placing a single molecule successively close and far from a dielectric interface and simultaneously measuring its photoluminescence decay and its orientation, both the radiative and non-radiative recombination rates can be determined. For CdSe nanocrystals, our results demonstrate that the fluorescence quantum efficiency, determined at the single molecule level, is 98% in average, far above the value expected from conventional ensemble experiments. The bi-dimensionnal nature of the transition dipole is also directly evidenced from a single particle measurement.