Photothermal synthesis of confined carbyne

The recent materialization carbyne confined to double-walled carbon nanotubes represents a major breakthrough in materials science but the control of its properties remains a major challenge. Here, localized photothermal heating through laser annealing and the possibility to perform Raman spectroscopy in-situ allow fabricating confined carbyne with tailored properties. Transmission electron microscopy shows the confined carbyne can reach about 10 nm in length. Evident interaction between the nanotubes and the confined carbyne alters the tube's diameter. Furthermore, the mechanism to tailor the properties of the confined carbyne could be associated to its corresponding Raman mode. The evolution of the synthesis constricted to the tube under increasing laser power can be monitored step by step from the moment the growth starts until a knock-off threshold is reached. Photothermal annealing represents a real possibility to synthesize carbyne confined to single-chirality carbon nanotubes, which is not entirely feasible otherwise.