SPLTRAK Abstract Submission
Optimized Near-Field Thermophotovoltaic Cell using InAs and InAsSbP
Gavin P Forcade1, Christopher E Valdivia1, Sean Molesky2,3, Shengyuan Lu2, Alejandro W Rodriguez2, Jacob J Krich4, Raphael St-Gelais4,5, Karin Hinzer1
1SUNLAB, Center for Research in Photonics, University of Ottawa, Ottawa, ON, Canada
/2Department of Electrical and Computer Engineering, Princeton University, Princeton, NJ, United States
/3Department of Engineering Physics, Polytechnique Montreal, Montreal, QC, Canada
/4Department of Physics, University of Ottawa, Ottawa, ON, Canada
/5Department of Mechanical Engineering, University of Ottawa, Ottawa, ON, Canada

Industrial waste heat is a free and abundant energy source, a quarter of which exists at medium grade temperatures of 600-900 K. For this temperature range, near-field thermophotovoltaics (NFTPVs) are theorized to be the most effective solid-state technology to recycle the waste heat into electrical power. NFTPV devices rely on the enhanced radiation transfer between a radiator and a thermophotovoltaic (TPV) cell separated < 0.2 μm, which can improve power density and efficiency. Unoptimized NFTPV devices and/or large bandgap TPV cells have limited experimental efficiencies of < 1% for 600-900 K radiators.
In this work, we employ a validated 2D drift-diffusion model to optimize an NFTPV device composed of a lattice matched double-heterostructured InAsSbP/InAs/InAsSbP TPV cell positioned 0.1 μm away from a 700 K radiator. Our optimized device shows a 5.6× higher above-bandgap energy transfer compared to the blackbody limit, which produces enhanced power density. Within the 600-900 K temperature range, we locate a maximum efficiency of 13.1% and maximum power output of 1.56 W/cm2 at 900 K, although for different radiator-TPV gaps of 0.1 μm and 0.01 μm, respectively. The maximum efficiency was reached for a larger radiator-TPV gap because of the high parasitic sub-bandgap energy transfer for radiator-TPV gaps less than 0.1 μm. At all temperatures, device efficiency is higher with near-field than far-field illumination.