From Structural Design to Molecular Mechanisms: The Evolution of Solar Evaporators

To address global water scarcity, solar-driven interfacial evaporation has emerged as a promising solution that minimizes energy consumption and environmental impact by harvesting solar energy directly at the air-water interface. Recent advances show that performance breakthroughs depend on the synergistic interplay between macroscopic structural designs and molecular-level mechanisms. This review traces the evolution of solar evaporators, from buoyancy-driven floating architectures and enhanced water transport enabled by capillary and osmotic pressure differences, to state-of-the-art regulation of water association states through hydrophobic interaction, hydrogen-bonding, and electrostatic interaction. These strategies accelerate mass transport, optimize solar energy utilization, lower evaporation enthalpy, and enhance long-term stability, achieving water transport rates up to 0.091 g min^-1, evaporation rates up to 6.92 kg m^-2 h^-1 under 1 kW m^-2 illumination, and salt rejection efficiencies above 99.99%. Despite these advances, challenges remain in achieving a precise mechanistic understanding of interfacial evaporation, scaling up fabrication, and standardized performance evaluation. This review highlights these issues and outlines future research directions to accelerate the practical deployment of solar-driven interfacial evaporation technologies for sustainable desalination and water purification.