3D Bioinspired Hair‐Based Solar Evaporator for Efficient Water Harvesting

Abstract Interfacial solar evaporation is a promising strategy for water purification, yet achieving both high efficiency and long‐term stability in saline environments remains challenging. Here, a broadband light absorption and thermal conversion strategy inspired by blackbody radiation principles to enhance solar evaporation performance is proposed. Human hair waste, exhibiting blackbody‐like radiative properties, is employed as a model system. The intrinsic broadband light trapping and favorable heat distribution, inherently low thermal conductivity, and cuticular scale structures synergistically improve heat utilization of human hair. Based on these advantages, a 3D solar steam generator composed of vertically aligned black hair is constructed. The device achieves a high evaporation rate of 3.945 kg m −2 h −1 (thermal efficiency 103%) and stable operation in 15 wt.% brine over 10 days. Furthermore, the evaporation rate is enhanced to 5.172 kg m −2 h −1 by integrating hollow truncated cone reflectors to optimize light distribution. Notably, the system exhibits edge‐preferential salt crystallization and self‐cleaning behavior, enabling continuous desalination. This work provides new theoretical insights into photothermal material design and highlights the potential of biomass‐derived resources for sustainable water purification technologies.