Orderly-assembled photothermal photonic crystals with multiple structural colors for high-performance interfacial solar desalination

The microstructure of photothermal materials plays a central role in interfacial solar evaporation, which is vital to solar absorption, thermal management, water and vapor transportation. Ordered structures constructed on cross-scale in a controllable fashion are potentially important for high-performance photothermic vaporization, and may provide fundamental insight into the correlation between microstructure and evaporation efficiency. Herein, the ordered photothermal materials featuring brilliant structural colors and spectral and thermal management are cross-scale assembled using unique colloidal photonic crystals (PCs) as the building block. Multidimensional ordered PC photothermal materials including PC layered nanofilms, microbeads and three-dimensional (3D) scaffolds are facially constructed by Langmuir-Blodgett, microfluidics and 3D printing techniques, respectively, exhibiting excellent internal light reflection and water wettability. As a result, the corresponding solar vaporization rates of 2.23, 2.14 and 2.0 kg m^-2h⁻¹ are achieved under 1 sun, greatly surpassing that in disordered PC films. Notably, the structural color originated from periodic-arranged PC structure shows a regulable and colorful appearance, in contrast to the monotonous black color in conventional broadband photothermal materials. The controllable methodology for ordered architecture construction inspires more novel nanostructured and multifunctional photothermal materials for solar evaporation materials.