Electrically driven ion pumping in a single walled carbon nanotube through coulomb drag

Coulomb drag-induced ion current flow is reported, achieved through coupling of electronic charge carriers along the lattice of a narrow single-walled carbon nanotube to electrolytic charge within the confines of the nanotube. Solid-state electrical contacts to the nanotube induce ion transport through it in the absence of an axial electric field; in the presence of such a field, the device behaves as an n-type ionic transistor. Ionic currents as high as 1nA have been recorded without alternate driving forces. Asymmetric functionalization of single walled carbon nanotube end groups further enhances the rectifying behavior of the device, yielding a current rectification ratio as high as 10 at moderate axial field strengths. By achieving ion pumping through a solid-state electrical input, the system offers promising solutions to nanoscale applications including purification, drug delivery, and desalination.