Spectroelectrochemical recognition of chemical dopants in the inner space of carbon nanostructures

By in situ Raman spectroelectrochemistry the state of chemical dopants in the inner space of potassium vapor treated single-walled carbon nanotubes (SWCNT), double-walled carbon nanotubes (DWCNT) and C-60 fullerene peapods was followed. We show that the spectroelectrochemistry is a method of choice to locate the dopant within carbon nanostructures. The presence of potassium inside the carbon nanostructures was found to be associated with a characteristic response of the tangential (TG) mode of SWCNT to electrochemical doping after treatment of the sample with the water. Our study confirmed the presence of residual potassium in peapods even after treatment with water. On the other hand, potassium was not found in the interior of the water-treated DWCNT and SWCNT.