Refractory Ultrathin Nanocomposite Solar Absorber with Superior Spectral Selectivity and Thermal Stability

Highly efficient solar-thermal energy conversion requires refractory absorbers harnessing full spectrum of sunlight, minimal thermal emission, and structural stability at higher operating temperatures. Herein, an ultrathin ultrabroadband omnidirectional silicon carbide-tungsten (SiC-W) refractory nanocomposite is fabricated by high-throughput co-sputtering with superior thermal and oxidation stability. The as-fabricated SiC-W nanocomposite (78 nm) deposited on tungsten layer with top anti-reflective film exhibits high solar absorptance of 95.45% in the wide range of 250-2500 nm with thermal emittance below 0.05 at ambient temperature. The ultrabroadband absorption is achieved by plasmonic resonances triggered by self-formed tungsten nanoclusters in the range of 500-1500 nm combined with SiC intrinsic absorption below lambda < 500 nm. SiC as diffusion barrier also prevents interlayer diffusion and oxidation of tungsten nanoclusters to achieve superior thermal/oxidation stability, when annealed at 900 K (air) and 1050 K (vacuum). This work demonstrates outstanding capability of refractory nanocomposites in high-performance solar thermal technologies for both terrestrial and space environments.