Coupled Charge and Radiation Transport Processes in Thermophotovoltaic and Thermoradiative Cells

TL;DR

This paper introduces a fully-coupled iterative model for charge and radiation transport in thermophotovoltaic and thermoradiative devices, revealing the importance of considering their interaction for accurate performance prediction.

Contribution

It develops the first fully-coupled model integrating charge and radiation transport, improving accuracy over previous methods that treated these processes separately.

Findings

Coupled modeling significantly affects photon recycling predictions.

Near-field effects are enhanced with the coupled approach.

Device performance predictions are more accurate with the new model.

Abstract

Accurate modeling of charge transport and both thermal and luminescent radiation is crucial to the understanding and design of radiative thermal energy converters. Charge carrier dynamics in semiconductors are well-described by the Poisson-drift-diffusion equations, and thermal radiation in emitter/absorber structures can be computed using multilayer fluctuational electrodynamics. These two types of energy flows interact through radiation absorption/luminescence and charge carrier generation/recombination. However, past research has typically only assumed limited interaction, with thermal radiation absorption as an input for charge carrier models to predict device performance. To examine this assumption, we develop a fully-coupled iterative model of charge and radiation transport in semiconductor devices, and we use our model to analyze near-field and far-field GaSb thermophotovoltaic and thermoradiative systems. By comparing our results to past methods that do not consider cross-influences between charge and radiation transport, we find that a fully-coupled approach is necessary to accurately model photon recycling and near-field enhancement of external luminescence. Because these effects can substantially alter device performance, our modeling approach can aid in the design of efficient thermophotovoltaic and thermoradiative systems.