Enhanced solar photocurrent using a quantum-dot molecule

Abstract

We present a detailed study on the influence of coherent tunneling on the photovoltaic properties of a semiconductor molecule driven by solar radiation. The connection between the power delivered by the quantum-dot molecule (QDM) and quantum coherence is not simply proportional but depends on interplay between the interdot coherent tunneling, the interaction of the system with thermal phonon reservoirs, and the resonance between the QDM and conduction bands. We explored numerically various parameter regimes and found that the maximum power delivered by the molecule is up to 30% greater than the power delivered by a single quantum-dot device. The calculated photovoltaic conversion efficiency is presented in terms of accessible experimental parameters and, as expected, is constrained by the second law.