Direct solar desalination exhibits considerable potential for alleviating the global freshwater crisis. However, the prevention of salt accumulation while maintaining high water production remains an important challenge that limits its practical applications because the methods currently employed for achieving rapid salt backflow usually result in considerable heat loss. Herein, we fabricate a solar evaporator featuring vertically aligned mass transfer bridges for water transport and salt backflow. The 3D open architecture constructed using mass transfer bridges enables the evaporator to efficiently utilize the conductive heat that would otherwise be lost, significantly improving the water evaporation efficiency without compromising on salt rejection. The fabricated evaporator can treat salt water with more than 10% salinity. Moreover, it can continuously and steadily work in a real environment under natural sunlight with a practical solar-to-water collection efficiency of >40%. Using the discharged water from reverse osmosis plants and sea water from the Red Sea, the evaporator demonstrates a daily freshwater generation rate of ~5 L/m2, which is sufficient to satisfy individual drinking water requirements. With strong salt rejection, high energy efficiency, and simple scalability, the 3D evaporator has considerable promise for freshwater supply for water-stressed and off-grid communities.

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What's more, to make the DPRC devices economical and manufactured in large scale, polymers and microspheres are applied. [15,[19][20][21][22] General DPRC applications should selectively emit thermal radiation in the atmospheric window and minimize solar absorption, simultaneously. However, for transparent applications (e.g., transparent electrode, [23,24] display device, [25][26][27] and window [28][29][30][31] ), only visible light (0.38-0.78 µm) is allowed for view or illumination. The rest of the solar radiation (mainly NIR: 0.78-2.5 µm), if transmitted will cause overheating or additional energy for cooling.Many transparent NIR filters are proposed to block the NIR solar radiation in recent years. [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] However, several NIR filters block the NIR solar radiation by absorption, [28][29][30][31][32][33][34][35][36] for example, W 18 O 49 , [28] Cu 2−x S/SiO 2 [29] and (NH4) x WO 3 , [32] which will increase the additional heating load as well. [33] To reduce the heating load, it is important to filter the NIR solar radiation by reflection. [33][34][35][36][37][38][39][40][41] Such NIR reflecting filters can be realized by a conductive layer, [33][34][35][36][37][38][39][40][41] for example, ITO [37,40] and dielectric/metal/ dielectric (D/M/D) structure. [38,39,41] However, these NIR reflecting filters will also show high reflections (low emissions) within mid-infrared (MIR) bands, which suppress the radiative cooling. [37][38][39][40][41][42][43][44] As the radiative cooling power in 8-13 µm is significant, [1][2][3][4][5][6] the MIR radiation heat transfer between the cold sky and a NIR filter shouldn't be neglected. To realize high visible transmission, NIR reflection and MIR emission, simultaneously, one can combine a NIR reflecting filter (e. g., D/M/D [38][39][40][41][42][43][44] or ITO [37] ) and a transparent MIR emitting structure (e. g., SiO 2 [45,46] or PDMS [37,47] ). As a common visible transparent NIR reflecting film in energy saving, a D/M/D structure is often used as a spectrally selective filter that can transmit most of the visible light and reflect NIR solar radiation. [38][39][40][41][42][43][44][45][46] Dielectric layers can enhance visible transmission due to a destructive multi-reflective interference and a thin metal layer is responsible for NIR reflection, [38][39][40][41][42][43][44][45] which is higher than that of an ITO structure. [38] As a polymer, PDMS will age especially under sunlight [48,49] and it is much thicker than a SiO 2 based emitter. [45,46] As a potential material for transparent radiative cooling, silica is stable with high transmittance over most of the solar wavelength range and also exhibits a strong phononpolariton resonance in the wavelength range of 8-13 µm. [45,46] However, there is an emission dip within 8-13 µm for a silica layer. [45] With 2D silica photonic crystals [45] or gratings, [46] silica can show enhanced MIR emission. As a result, it is expected With a high NIR reflection, a transparent radiativ...