Laser-induced transformation of freestanding carbon nanotubes into graphene nanoribbons

Graphene nanoribbons (GNRs) were successfully produced by using a laser to transform the tubular structure of multiwalled carbon nanotubes (CNTs). A laser beam was controlled to scan along the longitudinal axis of the freestanding aligned CNT sheets in air. As a result of the thermal interactions between the laser beam and CNTs, local oxidation was observed to happen at the graphitic walls of CNTs. This oxidative phenomenon was assisted by the laser-induced thermal expansion of the graphitic tube which transformed the tubular structure of CNTs. The direction of the laser irradiation led to the production of two-dimensional GNRs. The produced GNRs were freestanding and featured smooth surfaces. This laser scanning method was simple and industrially scalable to continuously produce GNRs.