Fabrication of an Omnidirectional 2D Photonic Crystal Emitter for Thermophotovoltaics

[摘要] In a thermophotovoltaic (TPV) system, a heat source brings an emitter to incandescence and the spectrally confined thermal radiation is converted to electricity by a low-bandgap photovoltaic (PV) cell. Efficiency is dominated by the emitter's ratio of in-band emissivity (convertible by the PV cell) to out-of-band emissivity (inconvertible). Two-dimensional photonic crystals (PhCs) offer high in-band emissivity and low out-of-band emissivity at normal incidence, but have reduced in-band emissivity off-normal. According to Lambert's law, most thermal radiation occurs off-normal. An omnidirectional PhC capable of high in-band emissivity at all angles would increase total in-band power by 55% at 1200°C. In this work, we present the first experimental demonstration an omnidirectional hafnia-filled 2D tantalum PhC emitter suitable for TPV applications such as combustion, radioisotope, and solar TPV. Dielectric filling improved the hemispherical performance without sacrificing stability or ease of fabrication. The numerical simulations, fabrication processes, and optical and thermal characterizations of the PhC are presented in this paper.

[发布机构] Institute for Soldier Nanotechnologies, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge; MA; 02139, United States^1;Department of Electrical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge; MA; 02139, United States^2;U.S. Army Natick Soldier Research Development and Engineering Center, 1 4th Ave., Natick; MA; 01760, United States^3;Department of Physics, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge; MA; 02139, United States^4

[效力级别] 能源学

[关键词] 2-D photonic crystals;Dielectric filling;Experimental demonstrations;Fabrication process;Thermal characterization;Thermophotovoltaic systems;Thermophotovoltaics;Two-dimensional photonic crystals