摘要：SummaryThis work experimentally studies a silicon-cored tungsten nanowire selective metamaterial absorber to enhance solar-thermal energy harvesting. After conformally coating a thin tungsten layer about 40 nm thick, the metamaterial absorber exhibits almost the same total solar absorptance of 0.85 as the bare silicon nanowire stamp but with greatly reduced total emittance down to 0.18 for suppressing the infrared emission heat loss. The silicon-cored tungsten nanowire absorber achieves an experimental solar-thermal efficiency of 41% at 203°C during the laboratory-scale test with a stagnation temperature of 273°C under 6.3 suns. Without parasitic radiative losses from side and bottom surfaces, it is projected to reach 74% efficiency at the same temperature of 203°C with a stagnation temperature of 430°C for practical application, greatly outperforming the silicon nanowire and black absorbers. The results would facilitate the development of metamaterial selective absorbers at low cost for highly efficient solar-thermal energy systems.Graphical AbstractDisplay OmittedHighlights•Si-cored tungsten nanowires are fabricated by conformal coating of 40-nm tungsten•Total solar absorptance of 0.85 with greatly reduced total emittance is achieved•Solar-thermal efficiency of 41% at 203°C under 6.3 suns is measured•74% efficiency at 203°C with a stagnation temperature of 430°C is projectedThermal Engineering; Thermal Property; Nanomaterials; Energy Materials
