Laser-induced production of large carbon-based toroids

We report on the production of large carbon-based toroids (CBTs) from fullerenes. The process involves two-step laser irradiation of a mixed fullerene target (76% C60, 22% C70). Transmission electron microscopy (TEM) clearly identifies toroidalshaped structures as well as Q-shaped constructs. The typical diameters of the CBTs are 0.2–0.3 mm with tubular diameters of 50–100 nm, but toroids as wide as 0.5 mm are observed making them nanostructures on the verge of being microstructures.