High-efficient plasmonic solar absorber and thermal emitter from ultraviolet to near-infrared region

Abstract

In this paper, the design and analysis of an ultra-broadband solar absorber based on the combination of two TiN metasurface resonators are presented. The absorber comprises a periodic array of combined TiN disk-square ring resonators located on a stack of TiO2/TiN films. The proposed absorber shows a high average absorption of 94% in the wavelength range of 250–3000 nm and provides a continuous bandwidth of 2200 nm (i.e., 250 nm to 2450 nm) for the absorption above 90%. The effects of geometrical parameters and the oblique incidences for both TE- and TM-polarized incident light on the absorption are discussed. Also, the impact of using other plasmonic metals instead of TiN is investigated. Simulation results obtained by the finite-difference time-domain (FDTD) method indicate a high absorption of about 80%, even for an oblique incidence up to 50° for both polarizations. Having outstanding properties like high absorption, ultra-wide bandwidth, independence to irradiance polarization, and insensitivity to radiation angle make the presented solar absorber a promising choice for various high-temperature applications like energy harvesting and emitting.