Chirality-controlled synthesis of single-walled carbon nanotubes-From mechanistic studies toward experimental realization

Carbon nanotubes (CNTs) have the recorded mechanical strength, exceptionally high thermal stability close to that of diamond, and an extremely high carrier mobility, which is two orders of magnitude higher than that of silicon. A CNT can be conducting, medium or small band gap semiconducting, depending on the exact atomic configuration and the tube diameter. To realize its applications in highend electronics and even replacing silicon in semiconductor industry, the synthesis of high-purity single-walled CNTs (SWCNTs) with unique structure (chirality) at a relatively low price, is essential. Direct synthesis of SWCNTs with the desired chirality has been one of the great challenges for more than 20 years and it is only very recently that direct synthesis of SWCNTs with purity >90% was achieved. In this review, we have summarized previous researches and state-of-the-art chirality-selective SWCNT synthesis, including experimental and theoretical studies dealing with the mechanism of SWCNT growth, potential routes toward chirality-selection during growth, and recent experimental techniques targeted toward the selective growth of high-purity SWCNTs.