Determination of redox states of (n,m)single-walled carbon nanotubes

Since the discovery of carbon nanotubes (CNTs), many groups have endeavored to understand the fundamental properties of the CNTs and explored their applications in nanomaterials science and engineering. The electronic structures of CNTs, one of the fundamental features of nanotubes, strongly depend on their chiralities. We discovered a method to determine the precise redox states of isolated single-walled carbon nanotube (SWNTs) having their own chirality indices; namely for the goal, we use in situ near-IR photoluminescence spectroelectrochemistry. This has been achieved by using a modifying polymer film on an indium tin oxide (ITO) electrode that retains the isolated SWNTs having chiralities of (6,5), (8,3), (7,5), (8,4), (10,2), (7,6), (9,4), (10,3), (8,6), (9,5), (12,1), (11,3), (8,7), (10,5), and (9,7) for HiPCO-SWNTs and (6,4), (7,3) and (9,1) for CoMoCAT-SWNTs. The spectroelectrochemical results were analyzed by the Nernst equation to determine their electronic states. Furthermore, the band gaps of (n,m)SWNTs were flound to be strongly affected by the change in micro-dielectric environments around the isolated (n,m)SWNTs.