Robust Ultrablack Coating for Omnidirectional Broadband Light Absorption

Abstract

Developing robust ultrahigh light absorption coatings has been a significant challenge, limited by the absorption‐adhesion tradeoff. Herein, a robust carbon‐based coating with omnidirectional broadband high absorption is designed and fabricated using a one‐step spray method. A novel rapidly cross‐linking resin is utilized as the binder to enhance adhesion. Beyond leveraging the intrinsic optical properties of carbon absorbents, the construction of a micro‐nano multi‐scale trapping structure is crucial for achieving high absorption efficiency in the coating. Innovatively, an inorganic matting agent is introduced to further diminish reflection by scattering incident light. The resulting ultrablack coating demonstrates good adhesion and an exceptionally high integral light absorption of 99.34% within the wavelength range of 1500–1800 nm, marking the highest reported value for binder‐incorporated spray coatings to date. This robust coating also exhibits outstanding thermal stability and resistance to vacuum thermal cycling and vibration. Furthermore, the application of the ultrablack coating via spraying is scalable and can be readily adapted to the surfaces or interiors of complex structural components made from diverse materials. The coating shows remarkable potential for solar energy harvesting and target stealth. This study presents a simple and efficient approach for developing robust ultrablack coatings suitable for widespread practical applications.