Ultra-broadband Perfect Metamaterial Absorber for Solar Energy Harvesting

We propose an ultra-broadband solar metamaterial absorber based on a three-layer Ti-SiO₂-Fe configuration. The top metal layer Fe is designed as a flat top pyramid structure to enhance the broadband absorption. The simulation results show that the absorber has a nearly perfect absorption performance in the wavelength range of 150–4150 nm with an average absorptance over 98%. The weighted average absorption efficiency (under AM 1.5G) is as high as 97.91%, showing that the designed absorber has a strong ability to collect energy from solar radiation. Furthermore, the photothermal conversion efficiency of the absorber is as high as 93.5% at the temperature of 1000 K. In addition, the absorber is not sensitive to the incident angle and polarization angle of light. The proposed ultra-broadband metamaterial absorber has enormous potential applications in many areas such as solar energy harvesting, optical sensor, solar cell and near-infrared detection.