Full spectrum efficient solar absorption through coupling light to multiple parts of a Ti strip

Abstract

Solar energy is a clean and renewable energy source with excellent exploitation potential. A three-layer structure is designed to couple light from free space and then absorb it. Simulation results show high average absorption of 98.7 % in the 400 to 3000 nm range under normal incidence. The average absorption rate for AM1.5 solar incident light source is up to 97.6 %. The designed structure matches the impedance of free space in the broadband range. Poynting vector evolution reveals that the short, medium and long wave ranges are absorbed mainly by the Ti strip's top, middle and bottom parts. This structure has a high absorption of over 98 % when changed to a centrosymmetric form, realizing polarization independence. The designed structures have the advantages of ultra-broadband, perfect absorption, high-temperature resistance, and polarization independence, which can be applied to solar thermal energy collections, thermoelectric and thermal emitters.

Keywords

• Solar energy
• Ultra-broadband
• Perfect absorption
• Poynting vector evolution