A bionic multi-interface evaporator for omnidirectional solar-driven reverse multistage desalination

Solar-driven interfacial photothermal desalination has emerged as a promising strategy for addressing the growing global freshwater shortage by directly converting solar energy into localized heat for water evaporation. Recent advances in reverse multistage designs have achieved high evaporation rates and efficient water recovery. However, existing designs typically employ a single photothermal interface, resulting in strong dependence on the solar incident angle and optimal performance only under near-vertical irradiation. This limitation restricts their practical deployment under realistic, time-varying sunlight conditions and highlights the need for desalination architectures that can operate efficiently across a wide range of irradiation angles. Here, inspired by the multidirectional light exposure characteristics of Chimonobambusa quadrangularis, we design and fabricate a bionic evaporator incorporating multiple photothermal interfaces. The resulting reverse multistage system exhibits markedly reduced sensitivity to the solar incident angle under one-sun illumination. Notably, the multistage evaporator achieves an evaporation rate of 4.55 kg m^-2 h^-1 and a solar-to-steam efficiency of 300% even under horizontal irradiation. This work provides a practical strategy for enabling the efficient operation of reverse multistage desalination systems, overcoming a key barrier to their real-world deployment.