Performance Analysis of a Near-Field Thermophotovoltaic Device with a Metallodielectric Selective Emitter and Electrical Contacts for the Photovoltaic Cell

TL;DR

This paper investigates a near-field thermophotovoltaic system with a multilayer tungsten-alumina emitter, demonstrating enhanced spectral heat flux and efficiency through surface plasmon coupling and optimized layer thicknesses, achieving 23.7% efficiency at 2000 K.

Contribution

It introduces a multilayer tungsten-alumina emitter design analyzed with fluctuational electrodynamics, revealing heat flux enhancement mechanisms and optimizing parameters for improved TPV performance.

Findings

Spectral heat flux is significantly enhanced with multilayer emitters.

Surface plasmon polariton coupling explains heat flux increase.

Achieved 23.7% conversion efficiency at 2000 K with optimized layers.

Abstract

A near-field thermophotovoltaic (TPV) system with a multilayer emitter of alternate tungsten and alumina layer is proposed in this paper. The fluctuational electrodynamics along with the dyadic Green function for a multilayered structure is applied to calculate the spectral heat flux, and the charge transport equations are solved to get the photocurrent generation and electrical power output. The spectral heat flux is much enhanced when plain tungsten emitter is replaced with multilayer emitter. The mechanism of surface plasmon polariton coupling in the tungsten thin film, which is responsible for the heat flux enhancement, is analyzed. In addition, the invalidity of effective medium theory to predict the optical properties of multilayer structure in near-field radiation is discussed. The tungsten and alumina layer thicknesses are optimized to match the spectral heat flux with the bandgap of TPV cell. Practically, with a gold reflector placed on the back of TPV cell, which also acts as the back electrode, and a 5-nm-thick indium tin oxide (ITO) layer as the front contact, when the emitter and receiver temperature are respectively set as 2000 K and 300 K, the conversion efficiency and electrical power output can be achieved to 23.7% and 0.31 MW/m2 at a vacuum gap distance of 100 nm.