Suspending Light-Absorbing Nanoparticles in Silica Aerogel Enables Numerous Superblacks

Current strategies for constructing sparse nanostructures for fabricating superblacks are only suitable for a few light-absorbing materials, severely limiting their applications. Herein, ultra-low reflective silica aerogels with ultra-high light transparency are used as solid smokes to individually or simultaneously suspend at least 100 species of light-absorbing nanoparticles with a volume fraction as low as 0.005%, for creating > 100 superblacks in practice and one billion superblacks in theory if taken permutation and combination among these 0D, 1D, or 2D nanoparticles into account. Depending on the composition of suspended nanoparticles and the structure of solid smoke, the resulting mechanically robust superblacks with supplementary properties including magnetism, full-spectrum absorption, high thermal stability, and excellent mechanical strength, are first observed. The wide choice of metallic or semiconductive LNs allows as-made superblacks to glitter in different catalytic reactions, and the resulting superblacks have been on-demand modified for endowing the self-cleaning performance in some contaminable environments. Benefiting from the superblack feature and porous network, these superblack monoliths have shown high-efficiency solar-heat conversion in some emerging light harvesting and managing fields. This powerful synthetic strategy for superblacks is expected to inspire researchers to conduct in-depth investigations on super-black optics, functional materials, etc.