Chemical Strain-Relaxation of Single-Walled Carbon Nanotubes on Plastic Substrates for Enhanced Conductivity

We have demonstrated that the conductivity of single-walled nanotube network films on plastic substrates is enhanced by a simple solvent treatment via chemical welding with aromatic hydrocarbons. The welding effect on the conductivity was confirmed by welding over a surface, the properties of which were controlled by deposition of reduced graphene oxide sheets on the substrate before deposition of the SWCNTs. The correlation between the sheet resistance and the interfacial structure of nanotubes on polyester substrates is further discussed in conjunction with a solvent-induced strain-relaxation of nanotubes and the geometrical change of nanotubes confirmed by atomic force microscopy and Raman spectroscopy after introducing solvents. We observe a clear reversible shift to higher energies in the G-mode band after chemical welding, indicating relaxation of the strain induced by the interface structure at the substrate and network junction.