Preparation of Ultrablack Composite Sheets with Excellent Mechanical and Chemical Stability from Sandpaper-Based Template-Imprinting

Ultrablack materials have applications in wide areas such as visible stealth, solar cells, and sea water evaporation. However, their high production cost, low mechanical property, and poor chemical stability have restricted their wide applications. Herein, a low-cost method is reported for preparing large-area ultrablack composite sheets with excellent mechanical and chemical stability. This is achieved by mixing a light absorber and transparent resin, and then copying and molding microconvex structures of sandpaper. The result shows that the absorption rate of the prepared composite sheet can reach more than 99% in the visible light range. More importantly, its performance remains almost unchanged after many cycles of mechanical stretching and long-term chemical soaking. This excellent ultrablack performance is mainly attributed to the light-trap effect of the subwavelength convex structure with the light absorber embedded in the resilient resin. Such composite sheets open a new pathway to developing high-performance ultrablack materials with practical applications.