A near-perfect metamaterial selective absorber for high-efficiency solar photothermal conversion

Abstract

High-efficiency solar metamaterial selective absorbers are indispensable technologies for new renewable energy, with significant application prospects in realizing high-efficiency solar photothermal and photoelectric conversion and desalination. Although various solar selective absorbers have been achieved, there are generally problems such as low efficiency, complex structure, and poor spectral selectivity. Herein, we propose a dual-dielectric-layer metamaterial selective absorber (DDMSA) that achieves near-perfect absorption in the entire solar spectrum while having low thermal radiation in the mid-infrared region. The proposed DDMSA can achieve strong absorption with an absorbance of above 90% over a wide spectrum from ultraviolet to near-infrared (i.e., from 280 to 2280 nm). This broadband strong absorption is attributed to several mechanisms, including interference effects, localized surface plasmon resonance (LSPR), propagating surface plasmon resonance (PSPR), and intrinsic losses of tungsten. An impressive solar photothermal efficiency surpassing 90% has been achieved spanning a broad temperature range from 100 to 1000 °C. Notably, it possesses superior performance in polarization-independent and wide-angle incidence behaviors. Therefore, the proposed metamaterial selective absorber has great potential in applications related to solar photothermal harvesting.