Extraordinary Sensitivity of the Electronic Structure and Properties of Single-Walled Carbon Nanotubes to Molecular Charge-Transfer

Rakesh Voggu, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for AdVanced Scientific Research,
Chandra S. Rout, Chemistry and Physics of Materials Unit, Jawaharlal Nehru Centre for AdVanced Scientific Research
Aaron D. Franklin, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University
Timothy Fisher, Birck Nanotechnology Center, Purdue University
C. N. R. Rao, Jawaharlal Nehru Centre for Advanced Scientific Research

Abstract

Interaction of single-walled carbon nanotubes with electron-donor and -acceptor molecules causes significant changes in the electronic and Raman spectra. Electron-donating molecules such as tetrathiafulvalene and aniline cause changes opposite to those caused by electron-withdrawing molecules such as nitrobenzene and tetracyanoethylene. Thus, a proportion of the semiconducting SWNTs becomes metallic on electron donation through molecular charge transfer. Electrical resistivity measurements reveal a systematic variation with electron-donating or -withdrawing power of the interacting molecules.