Fabry-Perot Cavity Based Selective Emitters Intended for Medium Grade Waste Heat Sources and Spectral Response of Silicon, Germanium and Gallium Arsenide Converter Cells for Thermophotovoltaic Systems

This research investigates the design and performance of Fabry-Perot cavity-based selective emitters for medium-grade waste heat sources focusing on their application in thermophotovoltaic (TPV) systems. A series of metal-insulator-metal multilayer stacks, comprising various metals (such as aluminum, tungsten, gold, silver, and titanium nitride) and dielec- trics, were analyzed, using the transfer matrix method (TMM) to determine their absorption and emission spectra. The goal was to optimize the selective emission properties for TPV systems using Silicon, Germanium and Gallium Arsenide converter cells. Results show that certain MIM structures, particularly those based on aluminum and silica, offer narrow absorption peaks that align with the bandgap wavelengths of these converter cells, maximizing efficiency while mini- mizing thermal losses. The study further explores the spectral response of the converter cells and the effect of material thickness, angle of incidence and polarization on the absorption spectra. This work demonstrates that tailored selective emitters can significantly affect the performance of TPV systems, contributing to enhanced energy efficiency in medi- um-grade heat recovery applications.