Synthesis of alkali-metal-doped C60 nanotubes

C60 nanotubes have been synthesized by a solution–solution method. After degassing in a dynamic vacuum, the C60 nanotubes doped with alkali metals by means of vapor evaporation method. Different temperatures have been studied to evaporate the alkali metals for the doping experiments. Raman spectrum was further employed to analyze the doping concentration of the obtained samples. It was found that all three alkali metals (Li, Na and K) used can be efficiently doped into the C60 nanotubes, forming AxC60 nanotubes. The doping concentration of Li, Na changed from low to high level, depending on the experiment temperatures, while K doping always gave saturated doping. The melt points, the ionic sizes and vapor pressures of alkali metals were thought to affect the final doping results.

Research Highlights
► Li, Na and K can be efficiently doped into C60 nanotubes.
► Metals’ melt points, ionic sizes, vapor pressures affect the doping concentration.
► The doping concentration of Li and Na changed, but K doping was always saturated.