A Materials’ Screening Paradigm for Thermophotovoltaic Optical Emitters

Thermophotovoltaics (TPV) represent a promising route for converting heat into usable electricity via a clean energy paradigm. Yet, the material options used to date for the optical emitters substantially restrict the power conversion efficiency of this process. Here, we provide a survey of material options, based on a dual-layer emitter stack (coating + substrate) that could be scaled up. We screened the optical behavior of &gt;2,800 material combinations with melting point &gt;2,000 oC, comprising refractory silicides, borides, carbides, nitrides, etc. [1]. The mismatch in permittivity allowed for emission control, key for the successful employment of high performing TPV. We identified optical emitters for TPV with theoretical efficiency &gt;50% for GaSb solar cells, while considering both optical properties and thermochemical stability. We analyzed the promising SiC/AlN option, where we found this material combination to be stable up to 1,200 oC in air and 1,500 oC in inert environments [2], using in situ high-temperature optical measurements [3]. Further, we quantitatively assessed the maximum power conversion efficiency using this emitter for TPV systems comprised of InGaAsSb, InGaAs, Ge, GaSb, and Si photovoltaics. The material screening approach implemented here could be expanded to additional high-temperature photonic devices, such as thermal regulation ones, and barrier coatings for extreme environmental conditions.<br/><br/>[1] M. R. S. Dias et al. Joule 7, 2209 (2023).<br/>[2] M. Duncan et al. In preparation (2024).<br/>[3] T. Gong et al. ACS Appl. Opt. Mater 1, 1615 (2023).