Selective emitters for thermophotovoltaic applications

Applying thermophotovoltaic (TPV) technologies to existing energy generators allows us to increase energy output while utilizing present infrastructure by reclaiming the heat lost during the production process. In order to maximize the efficiency of these sources, the conversion efficiency of the TPV system needs to be optimized. Selective emitters are often used to tailor the spectrum of incident light on the diode, blocking any undesirable light that may lead to device heating or recombination. Over the years, many different technologies have been researched to create an ideal selective emitter. Plasmas and rare‐earth emitters provided highly selective spectra early on, but their fixed peaks required tailoring the diode's band gap to the emitter's characteristic wavelength. Recent advances in engineerable materials, such as photonic crystals and metamaterials, allow the opposite to take place; an appropriate selective emitter can be designed to match the TPV diode, allowing the diode structure to be optimized independently from the emitter. The dramatic improvement of III‐V film quality in the past decade has caused a resurgence in thermophotovoltaic (TPV) cell development. The selective emitter, as part of the complete TPV system, allows use of a wide range of energy sources. Early development of these emitters utilized inherent atomic properties while more recent technologies leverage complex electromagnetic effects to engineer custom solutions.