Supramolecular doping for the stabilization of n-type carbon nanotubes

Abstract

Nanocarbons, including carbon nanotubes, have been widely studied for the construction of human-friendly and wearable electronics and power modules. However, the absence of air- and thermally-stable n-type nanocarbon materials has hindered the development of practical PN junction devices such as field effect transistors, photovoltaic cells and thermoelectric modules. Here we solve this issue by using soft chemistry with ordinary salt-crown ether complexes. Thermoelectric property measurements revealed that various ordinary salts convert p-type carbon nanotubes to air-stable n-type forms efficiently in the presence of crown ethers. The n-type carbon nanotubes were stabilized by the coordination of alkali metal-crown ether host-guest complexes. This material showed excellent n-type thermoelectric properties, and unprecedented thermal stability in air.