3D self-assembly of aluminium nanoparticles for plasmon-enhanced solar desalination

Plasmonics has generated tremendous excitement because of its unique capability to focus light into subwavelength volumes(1), beneficial for various applications such as light harvesting(2,3), photodetection(4), sensing(5), catalysis(6) and so on. Here we demonstrate a plasmon-enhanced solar desalination device, fabricated by the self-assembly of aluminium nanoparticles into a three-dimensional porous membrane. The formed porous plasmonic absorber can float naturally on water surface, efficiently absorb a broad solar spectrum (>96%) and focus the absorbed energy at the surface of the water to enable efficient (similar to 90%) and effective desalination (a decrease of four orders of magnitude). The durability of the devices has also been examined, indicating a stable performance over 25 cycles under various illumination conditions. The combination of the significant desalination effect, the abundance and low cost of the materials, and the scalable production processes suggest that this type of plasmon-enhanced solar desalination device could provide a portable desalination solution.