Wood-based Superblack

Abstract

Abstract The promise of superblack materials to revolutionize energy harvesting and optoelectronic technologies has been constrained by their cost and mechanical fragility. Here we report on a simple strategy, guided by computational methods, to develop robust superblack materials following metal-free wood delignification and carbonization (1500 oC). Subwavelength severed cells evolve under shrinkage stresses, yielding vertically aligned fibrillar arrays with a thickness of ~100 µm and light reflectance as low as 0.36 %, on par with conventional superblack materials. The negated light reflection is independent of the incidence angle and wood density. Moreover, our measurements indicate a laser beam reflectivity three-fold lower than commercial light stoppers in current use. Overall, the new wood-based superblack material is introduced as a mechanically strong and cost-effective surrogate for microfabricated carbon nanotube arrays.