A robust synthesis route of confined carbyne

The unique mechanical, optical, and electrical properties of carbyne, a one-dimensional allotrope of carbon, make it a highly promising material for various applications. It has been demonstrated that carbon nanotubes (CNTs) can serve as an ideal host for the formation of confined carbyne (CC), with the yield being influenced by the quality of the carbon nanotubes for confinement and the carbon source for carbyne growth. In this study, a robust synthesis route of CC within CNTs is proposed. C70 was utilized as a precursor to provide an additional carbon source, based on its ability to supply more carbon atoms than C60 at the same filling ratio. Multi-step transformation processes, including defect creation, were designed to enhance the yield of CC. As a result, the yield of CC was significantly increased for the C70 encapsulated single-walled CNTs by more than an order of magnitude than the empty counterparts, which also surpasses that of the double-walled CNTs, making it the most effective route for synthesizing CC. These findings highlight the importance of the additional carbon source and the optimal pathway for CC formation, offering valuable insights for the application of materials with high yield.