Carbon Vesicles: A Symmetry‐Breaking Strategy for Wide‐Band and Solvent‐Processable Ultrablack Coating Materials
Jing Guo, Dongdong Li, Zhenchao Qian, Heng Luo, Meng Yang, Qianxiang Wang, Jian Xu, Ning Zhao
Abstract
Abstract Solvent‐processable ultrablack materials have obvious application convenience in many situations, such as absorbing coatings on large and complex surfaces. However, developing solvent‐processable ultrablack materials with high light‐absorption performance and wide absorption band remains a great challenge. In this article, carbon vesicles (CVs) are fabricated for solvent‐processable ultrablack coating. The fabrication process involves a templated co‐condensation of silica and resorcinol formaldehyde resin (RF resin), followed by carbonization and template removal. The resultant structure shows a very thin inner layer, a rough outer layer, as well as a nano‐porous interlayer. This structure introduces randomness and breaks the spherical symmetry of the common carbon hollow spheres. As a result, structural color due to inner‐particle interference is avoided. In addition, the as‐fabricated CVs show a wide‐band low reflectance because of its low carbon filling ratio and nanoscale scatterer size. The lowest reflectance reaches ≈0.10% at 360 nm, making it the darkest solvent‐processable ultrablack material ever reported. The symmetry‐breaking strategy presented here provides an efficient way for the design of solvent‐processable ultrablack materials.