Designing Small Silicon Quantum Dots with Low Reorganization Energy

TL;DR

This paper uses first principles analysis to explore strategies for designing silicon quantum dots with low reorganization energy, aiming to enhance exciton coherence and reduce decoherence in quantum dot solids.

Contribution

It introduces four approaches to reduce exciton-phonon coupling in silicon quantum dots, enabling improved control over excitonic properties and coherence.

Findings

Strategies can mitigate polaronic effects in quantum dot solids

Designs can alter spectral density to reduce decoherence

Potential to support partially coherent exciton transport

Abstract

A first principles, excited state analysis is carried out to identify ways of producing silicon quantum dots with low excitonic reorganization energy. These focus on the general strategy of either reducing or constraining exciton-phonon coupling, and four approaches are explored. The results can be implemented in quantum dot solids to mitigate polaronic effects and increase the lifetime of coherent excitonic superpositions. It is demonstrated that such designs can also be used to alter the shape of the spectral density for reorganization so as to reduce the rates of both decoherence and dissipation. The results suggest that it may be possible to design quantum dot solids that support partially coherent exciton transport.