Design and optical performance investigation of all-sprayable ultrablack coating

Although ultrablack surfaces are urgently needed in wide applications owing to their extremely low reflectance over a broadband wavelength, obtaining simultaneously the ultrablackness and mechanical robustness by simple process technique is still a great challenge. Herein, by decoupling different light extinction effects to different layers of coating, we design an ultrablack coating that is all-sprayable in whole process. This coating presents low reflectance over visible–mid-infrared (VIS–MIR) wavelength (av. R ≈ 1% in VIS), low multi-angle scattering (bidirectional reflection distribution function (BRDF) = 10⁻²–10⁻³ sr⁻¹), together with good substrate adhesion grade and self-cleaning ability, which are superior to most reported sprayable ultrablack surfaces. The light extinction effects of each layer are discussed. This method is also applicable in other material systems.