High-Pressure Synthesis of 1D Low-Bandgap Polymers Embedded in Diamond-like Carbon Nanothreads

Abstract

The synthesis of hydrogenated carbon nanothreads at tens of GPa from aromatic systems is one of the most brilliant recent findings in high-pressure science. C-nanothreads combine the high tensile strength of diamond with the high flexibility of polymers, and many efforts are currently being undertaken to taylor some useful physicochemical properties by smartly modifying their local structure. We present the synthesis of double core diamond-like nanothreads with the two cores being bound by a conjugated C, polyacetylene-like backbone. The two cores also form a protecting sheath for the backbone. This material exhibits an optical bandgap of 1.74 eV, similar to polyacetyelene; it is then very attractive as a potential organic semiconductor with simultaneous outstanding mechanical properties. The synthesis was achieved by reacting diphenylacetylene in diamond anvil cells, at 25–30 GPa and room temperature, and the materials were characterized by optical spectroscopy, synchrotron X-ray diffraction, and ab initio computer simulations.