Luminescent Solar Concentrator-Enhanced Hydrogel-Based Solar Evaporator for a High Evaporation Rate and Good Salt Resistance

Interfacial solar evaporation represents one of the most promising strategies to mitigate the global freshwater scarcity crisis. Hydrogels have emerged as an attractive platform for water evaporation due to exceptional water transport capabilities. However, hydrophilic hydrogels with densities exceeding that of water often require external floating supports to maintain interfacial evaporation, and the utilization of the floating platform has been overlooked. In addition, there are few research studies focusing on augmenting incident solar energy through a chemical luminescent solar concentrator (LSC). In this work, a novel structure by combining an LSC with a solar evaporator was designed. We integrated an LSC with a polydopamine/polyacrylamide (PDA/PAM) hydrogel-based evaporator to enhance light harvesting and thereby improve evaporation performance. The PDA/PAM hydrogel evaporator attained an evaporation rate (central hydrogel) of 3.85 kg m –2 h –1 under 1 sun in 3.5 wt % NaCl solution. In outdoor experiments, by using local river water, the device achieved a maximum apparent evaporation rate of 3.0 kg m –2 h –1 while simultaneously enabling water purification. Furthermore, the evaporator demonstrated exceptional salt resistance, exhibiting no salt accumulation during 4 h of operation in 20 wt % NaCl solution and maintaining stable performance over 30 consecutive evaporation cycles in real seawater.