Radiative recombination of charged excitons and multiexcitons in CdSe quantum dots

TL;DR

This study uses semi-empirical pseudopotential calculations to analyze the emission spectra of charged excitons and multiexcitons in CdSe quantum dots, revealing shifts and additional peaks related to charge states and electron-hole recombination.

Contribution

It provides new insights into the emission characteristics of charged multiexcitons in CdSe nanocrystals through detailed computational analysis.

Findings

Main emission peak of charged multiexcitons is blue shifted compared to neutral excitons.

Negatively charged biexcitons show additional higher-energy emission peaks.

Recombination involving p-states contributes to observed spectral features.

Abstract

We report semi-empirical pseudopotential calculations of emission spectra of charged excitons and biexcitons in CdSe nanocrystals. We find that the main emission peak of charged multiexcitons - originating from the recombination of an electron in an s-like state with a hole in an s-like state - is blue shifted with respect to the neutral mono exciton. In the case of the negatively charged biexciton, we observe additional emission peaks of lower intensity at higher energy, which we attribute to the recombination of an electron in a p state with a hole in a p state.