# Enhancing thermophotovoltaic performance using graphene-BN-InSb near-field heterostructures

## TL;DR

This paper demonstrates that graphene-BN-InSb near-field heterostructures can significantly enhance thermophotovoltaic power output and efficiency within industrial waste heat temperature ranges, surpassing conventional thermoelectric devices.

## Contribution

It introduces optimized graphene-BN-InSb heterostructures for near-field thermophotovoltaic systems, achieving high power and efficiency through resonant coupling mechanisms.

## Key findings

- Maximum power density of 3.5×10^4 W/m^2 achieved.
- Efficiency reaches up to 27% of Carnot limit.
- Performance can surpass state-of-the-art thermoelectric devices.

## Abstract

Graphene---hexagonal-boron-nitride---InSb near-field structures are designed and optimized to enhance the output power and energy efficiency of the thermophotovoltaic systems working in the temperature range of common industrial waste heat, $400~\rm K \sim 800~\rm K$, which is also the working temperature range for conventional thermoelectric devices. We show that the optimal output electric power can reach $3.5\times10^{4} \rm\ W/\rm m^2$ for the system with a graphene---hexagonal-boron-nitride heterostructure emitter and a graphene-covered InSb cell, whereas the best efficiency is achieved by the system with the heterostructure emitter and an uncovered InSb cell (reaching to $27\%$ of the Carnot efficiency). These results show that the performances of near-field thermophotovoltaic systems can be comparable with or even superior than the state-of-art thermoelectric devices. The underlying physics for the significant enhancement of the thermophotovoltaic performance is understood as due to the resonant coupling between the emitter and the cell, where the surface plasmons in graphene and surface phonon-polaritons in boron-nitride play important roles. Our study provides a stepping stone for future high-performance thermophotovoltaic systems.