3D printed solar-driven interfacial evaporator: From photothermal materials to advanced architectures

Solar driven interfacial water evaporation (SDIE) has emerged as a green and efficient strategy for freshwater production, where the three dimensional (3D) structural design of photothermal evaporators is critical to substantially enhancing evaporation performance. This paper systematically reviews the research progress on photothermal evaporators, with a particular focus on those fabricated via 3D printing. The fundamental photothermal conversion mechanisms, namely localized surface plasmon resonance (LSPR), nonradiative relaxation (NRR), and molecular thermal vibration (MTV), are thoroughly elucidated. Subsequently, the state-of-the-art research status of advanced photothermal conversion materials, including polymers, carbons, metals, semiconductors, and other novel materials, is comprehensively summarized, with an emphasis on the regulatory effects of material composition and microstructure on evaporation performance. On this basis, the characteristics of three mainstream 3D printing technologies, including Powder Bed Fusion (PBF), Material Extrusion (MEX), and Vat Photopolymerization (VPP), as well as their applications in the integrated fabrication of 3D evaporators are introduced, and the progress of 3D-printed photothermal evaporators is overviewed. Furthermore, the cutting-edge development trends of salt crystallization resistance, as well as those of multifunctional photothermal evaporators for volatile organic compounds (VOCs) degradation and water-electricity cogeneration are projected. This review aims to provide instructive guidance for the design and fabrication of high efficiency, stable, and multifunctional photothermal evaporators.