Solar steam generation has been achieved by surface plasmon heating with metallic nanoshells or nanoparticles, which have inherently narrow absorption bandwidth. For efficient light-To-heat conversion from a wider solar spectrum, we employ adiabatic plasmonic nanofocusing to attain both polarization-independent ultrabroadband light absorption and high plasmon dissipation loss. Here we demonstrate large area, flexible thin-film black gold membranes, which have multiscale structures of varying metallic nanoscale gaps (0-200 nm) as well as microscale funnel structures. The adiabatic nanofocusing of self-Aggregated metallic nanowire bundle arrays produces average absorption of 91% at 400-2,500 nm and the microscale funnel structures lead to average reflection of 7% at 2.5-17 mm. This membrane allows heat localization within the few micrometre-Thick layer and continuous water provision through micropores. We efficiently generate water vapour with solar thermal conversion efficiency up to 57% at 20kWm2. This new structure has a variety of applications in solar energy harvesting, thermoplasmonics and related technologies.
Bibliographical noteFunding Information:
This research was supported by Basic Science Research Program and the Pioneer Research Center Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT and Future Planning (NRF-2015R1A2A2A11001112, NRF-2013M3C1A3065045), the Low Observable Technology Research Center Program of the Defense Acquisition Program Administration and Agency for Defense Development and an Asian Office of Aerospace R&D grant, FA2386-15-1-4024 (15IOA024).
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Biochemistry, Genetics and Molecular Biology(all)