Silk-based systems for highly efficient photothermal conversion under one sun: portability, flexibility, and durability

As one of the most promising techniques for harvesting solar energy, solar-powered generation of steam has great potential for application in sterilization, desalination, and other industrial processes. Although various methods of solar-powered steam generation have been reported, it remains a challenge to develop solar steam generators with durability, portability, and high photothermal performance for practical use. In this study, a novel device composed of reduced graphene oxide and silk fabric (RGO-silk-fabric) was demonstrated for highly efficient, solar-driven generation of steam. The unique fabric structure of silk and the broadband absorption by RGO allowed the RGO-silk-fabric to exhibit high light absorption in the wavelength range of 300 to 2500 nm. Benefitting from the capillary effect and superb air permeability, the RGO-silk-fabric system with a thermal insulator (polyethylene foam) exhibited remarkably high photothermal performances (an evaporation rate of 1.48 kg m(-2) h(-1)) under one sun irradiation (1 kW m(-2)), even with minimal RGO content. Moreover, the RGO-silk-fabric showed great washability, flexibility, and excellent mechanical strength for low-cost, durable, and portable solar-steam applications. The simple fabrication process and scalability of the RGO-silk-fabric are expected to promote widespread application of the approach in water purification and other industrial processes.