Ultra-Broadband Spectrally Selective Absorber for Solar Thermal Absorption Based on TiN Square-Ring Meta-Structure

Abstract

Based on the TiN square-ring structure, a spectrally selective absorber for solar thermal absorption is proposed announcing an average absorption of 95.69% in the major solar spectral region (280nm~2500nm). When the wavelength exceeds 2500nm, the absorption declines rapidly and decreases to 40.4% at the wavelength of 4000nm, showing excellent spectral selectivity. As the incident angle of TE or TM polarized wave varies in a range of 0~60 degrees, the proposed absorber maintains more than 90% solar absorption efficiency, which proves the insensitivity of incident angle and polarization angle. With operating temperature T=300K and solar concentrating coefficient C=1, the solar-thermal conversion efficiency of the proposed absorber is 93.92%. At a high temperature of 700℃, the solar-thermal conversion efficiency can maintain more than 80% at the condition of C=200, demonstrating good thermal tolerance. It is believed that the proposed absorber has great potential to be applied in solar thermal absorption systems.

Perfect Solar Absorber Based on Four-Step Stacked Metamaterial

“…It is crucial to utilize the 300-2500 nm band to its full potential, as the solar radiation spectra of the AM1.5 shows that energy is concentrated in the ultraviolet, visible light, and infrared range. Solar absorbers have proven to be more efficient and have a broader bandwidth than solar cells and thermal power generation [5,6].…”