Narrow-gap, semiconducting, superhard amorphous carbon with high toughness, derived from C60 fullerene

New carbon forms that exhibit extraordinary physicochemical properties can be generated from nanostructured precursors under extreme pressure. Nevertheless, synthesis of such fascinating materials is often not well understood. That is the case of the C60 precursor, with irreproducible results that impede further progress in the materials design. Here, the semiconducting amorphous carbon, having band gaps of 0.1–0.3 eV and the advantages of isotropic superhardness and superior toughness over single-crystal diamond and inorganic glasses, is produced from fullerene at high pressure and moderate temperatures. A systematic investigation of the structure and bonding evolution is carried out with complementary characterization methods, which helps to build a model of the transformation that can be used in further high-pressure/high-temperature (high p,T) synthesis of novel nano-carbon systems for advanced applications. The amorphous carbon materials produced have the potential of accomplishing the demanding optoelectronic applications that diamond and graphene cannot achieve. [Display omitted] •Narrow-gap, superhard amorphous carbon materials are formed from compressing C60•Two distinct, short-range microstructures in the amorphous carbon are recognized•A long-missing structural transformation model is developed from C60 to amorphous carbon Synthesis of amorphous carbon from fullerene C60 under extreme pressure is often not well understood, which impedes further progress in the materials design. Zhang et al. propose a long-missing structural transformation model from C60 to amorphous carbon and raise the future development of amorphous carbon with controllable disorder.