Solar energy harvester based on polarization insensitive and wide angle stable UWB absorber for UV, visible and IR frequency range

This paper proposes an ultrawideband electromagnetic absorber operating in the infrared, visible light, and ultraviolet regime. The overall structure of the proposed absorber is made up of multiple square rings arranged in a symmetrical configuration. The absorber consists of three layers, the ground layer made of nickel, the intermediate substrate layer is made of polyimide and the top layer is constructed from nickel. The overall unit cell dimension of 119 nm × 119 nm × 31 nm has been proposed for the optimum performance of the absorber. It has absorption (A) of more than 90 % for the frequency range of 131.59 THz to more than 4500 THz. The proposed absorber is polarization-independent. The absorber shows more than 70 % absorption for incident angle<65° in both transverse electric and transverse magnetic modes. The absorber covers the range of infrared, visible, and ultraviolet frequencies. Using this proposed absorber, high solar absorption efficiency (η_A) of 96.84 % and high thermal emission efficiency (η_E) of 90.19 %, 92.54 %, 95 % and 96.64 % are achieved at 1000K, 1500K, and 2500K & 3500 K, respectively. Due to the ultrawideband characteristic of the proposed design in the infrared, visible, and ultraviolet regimes, the proposed design can be used as a highly efficient absorber in many applications such as photovoltaics, photo-detectors, thermal emitters, IR (Infrared) detectors, cloaking, solar energy harvesting, sensing, and UV (Ultra-Violet) protection.