Design and Utilization of Infrared Light for Interfacial Solar Water Purification

Clean drinking water is increasingly perceived as one of the most critical global challenges. Direct solar desalination with a minimal carbon footprint is a promising technology to alleviate the water challenge. However, this technology still faces a series of problems, such as poor salt-rejection of the absorber and low condensation efficiency and water output. Currently, the design and utilization of infrared light shows unique advantages in solving these problems. With this background, this Focus Review aims to summarize the state-of-the-art progress of three infrared-light-based strategies for direct solar desalination: the use of selective absorbers to obtain higher solar-to-vapor conversion efficiency, the use of radiative energy to indirectly heat the water to resolve the salt-rejecting problem of the absorber, and use of radiative cooling to enhance the output of freshwater. Also, unsolved scientific and technical issues associated with the outlook in these directions are discussed, with the hope of further promoting direct solar desalination for sustainability and global welfare.