Multi-angle wide-spectrum light-trapping nanofiber membrane for highly efficient solar desalination

• A highly efficient photo-thermal membrane was fabricated with 3D light-trapping structure. • The membrane has broad spectrum and wide range of absorption angles of light. • The membrane has excellent photothermal conversion capacity, efficient solar desalination performance and salt resistance. • The membrane is scale production, low-cost, and recyclable. Solar-driven interfacial water evaporation has been recognized as one of the promising methods to solve the problem of fresh water shortage. However, due to the dependence of the incident angle of light, the light absorption performance of materials in practical applications is limited. Herein, a three-dimensional (3D) light-trapping structure was constructed by zinc oxide nanowires within carbon-based nanofiber membrane using electrospinning technology, hydrothermal growth and magnetron sputtering techniques for multi-angle wide-spectrum light absorption. It has excellent average absorption (>90 %) performance in a wide range of angles (0°- 80°), and a rapid photo-thermal conversion capacity (70℃ after 30 s solar illumination), which are higher than that in previous literature. The average absorption of light from 200 to 2500 nm can reach 95 %. Under 1 sun irradiation (1 kW m - 2 ), the solar evaporation rate can reach 1.73 kg m -2 h - 1 , and the evaporation efficiency can reach 94 %. The multi-angle wide-spectrum light-absorption of the membrane might provide a promising strategy for collecting water in other practical applications.