Effect of charging on CdSe/CdS dot-in-rods single-photon emission

TL;DR

This study investigates how charging affects the single-photon emission properties of CdSe/CdS dot-in-rods nanocrystals, revealing the impact of charge states on photon statistics and emission quality.

Contribution

It introduces a post-selection method to distinguish neutral and charged states, providing new insights into their different emission behaviors.

Findings

Charged states degrade single-photon purity.

Two emitting states identified: exciton and trion.

Quantum yields differ between neutral and charged states.

Abstract

The photon statistics of CdSe/CdS dot-in-rods nanocrystals is studied with a method involving post-selection of the photon detection events based on the photoluminescence count rate. We show that flickering between two states needs to be taken into account to interpret the single-photon emission properties. With post-selection we are able to identify two emitting states: the exciton and the charged exciton (trion), characterized by different lifetimes and different second order correlation functions. Measurements of the second order autocorrelation function at zero delay with post- selection shows a degradation of the single photon emission for CdSe/CdS dot-in-rods in a charged state that we explain by deriving the neutral and charged biexciton quantum yields.