Sandwich-structured evaporator with multilayer confined heating interface for boosting solar vapor generation

• The proposed sandwich-structured evaporator is composed of multilayer light-absorbing layers and water absorption layers, which is significant different from traditional evaporators. • The area of heating interface is controllable in a simple manner. • So fabricated sandwich-structured evaporator can achieve a high water evaporation rate of 2.145 kg m −2 h −1 , outperforming most related materials. Achieving interfacial localized heating and generating abundant heating interface have been verified two critical factors to promote solar energy utilization and vapor generation rate, but still a great challenge. Herein, a sandwich-structured evaporator composes of multilayer Cu-CuO meshes and non-woven cotton via a physical layer-by-layer assembly method is reported, which is obviously different from the currently reported evaporators that only have one light-absorbing layer, thus it is conducive to expose abundant heating interface in a controllable manner, and resulting in the finely designed sandwich-structured evaporator can achieve a high evaporation rate approximately 2.145 kg m −2 h −1 . With the advantages of high evaporation rate, cost-effectiveness, simplicity, and reliable drinkable water yields from high-concentration brine, simulated seawater, dye wastewater, and heavy metal wastewater, this novel sandwich-structured design provides a new avenue to build up high-performance solar vapor generation systems.