Ultra-broadband, near-perfect and thin-film scale solar absorber based on semiconductor-metal nanocone

In this paper, a solar energy absorber consisting of a periodic array of GaAs-Ti disks placed on the surface of a metal substrate tungsten (W) is proposed to realize the ultra-wideband, near-perfect absorption. The absorption characteristics of the absorber are investigated theoretically by using of the finite-difference time-domain method (FDTD). The researched results indicate that the absorption bandwidth with the absorption rate of over 90% exceeds 3400 nm, which is wider than that of the advanced solar energy absorption reported previously. The average absorption rate of this absorber at this bandwidth is up to 96.2%. The solar spectral weighted absorption efficiency η reaches 96.1%, and the ratio of the missed energy γ drops to 0.039. What’s more, the absorption performance of the absorber with different parameters, structures and materials is investigated systematically to determine the best absorption performance. The researched results discovery that propagating surface plasmons (PSPs), cavity modes, guided mode resonances (GMRs), localized surface plasmons (LSPs), plasmonic coupling and their synergy are excited to achieve the ultra-broadband and near-perfect absorption in visible and infrared wavelengths. It also has the characteristics of independent incident and polarization angles. These excellent properties and attractive findings demonstrate that the proposed solar absorber has more extensive applications in the field of energy collection and energy conversion.