Transparent selective photothermal coatings for antifogging applications

Surface fogging reduces light transmission of optically clear materials and causes various problems in daily life. Transparent photothermal materials have recently emerged as an eco-friendly and sustainable solution to surface fogging. However, most reported photothermal materials only exploited the broadband spectrum of solar energy, and the spectral feature has yet to be tuned to optimize the visibility and photothermal effect simultaneously. Here, we develop a highly transparent, photothermally selective coating, based on solution-processed cesium-doped tungsten trioxide nanoparticles. The transparent selective photothermal coating provides a visible transmittance up to 82% and a high absorption of ultraviolet and near-infrared light >90%, and achieves a temperature increase by 38°C under 1-sun illumination, resulting in remarkable antifogging and defogging abilities under extremely frigid or humid conditions. Large-scale complex surfaces with photothermal coatings are deployed in field antifogging tests as well as long-term durability tests, showing their great potential in antifogging applications.