Quantum simulation of multiple-exciton generation in a nanocrystal by a single photon

TL;DR

This paper presents a theoretical study demonstrating that small nanocrystals can efficiently generate multiple excitons from a single photon, with dynamics influenced by exciton-biexciton coupling and phonon relaxation.

Contribution

It introduces a quantum simulation approach that models complex exciton dynamics in nanocrystals, revealing conditions for efficient multiple exciton generation.

Findings

Efficient MEG observed in small nanocrystals within picoseconds.

Fast exciton-biexciton coupling is essential for MEG before phonon relaxation.

Quantum simulations include hundreds of thousands of exciton states.

Abstract

We have shown theoretically that efficient multiple exciton generation (MEG) by a single photon can be observed in small nanocrystals (NCs). Our quantum simulations that include hundreds of thousands of exciton and multi-exciton states demonstrate that the complex time-dependent dynamics of these states in a closed electronic system yields a saturated MEG effect on a picosecond timescale. Including phonon relaxation confirms that efficient MEG requires the exciton--biexciton coupling time to be faster than exciton relaxation time.