Broadband High-Efficiency Solar Absorber Based on Tungsten Hole-Mesh

Abstract

Solar energy is widely considered a “green energy” source, and to maximize its utilization, efficient solar absorbers that can absorb solar energy at various optical frequencies are necessary. We report a high-performance, broadband solar absorber made of just two materials –W and Al2O3. The absorber is composed of three layers, arranged from top to bottom: an Al2O3 dielectric layer, a W hole-mesh layer, and a W substrate layer. Finite difference time domain method analysis simulations demonstrated an ultra-high absorption rate of 97.64% across a wide spectrum of visible and near-infrared light. The high absorption rate is attributed to the combined effects of surface plasmon resonance, cavity resonance, and the high imaginary part of the permittivity of tungsten. Furthermore, we analyzed the influence of the geometric parameters of the W hole-mesh absorber on the absorption performance and explained the physical mechanism of the high absorption rate by analyzing impedance matching. Interestingly, the absorber is insensitive to polarized light and can still maintain a high absorption rate of 90% at an incident angle of 0–60°. Our findings indicate that the W hole-mesh absorber has significant advantages in solar energy harvesting, paving the way for more efficient and cost-effective solar energy technology.