Improved conduction in transparent single walled carbon nanotube networks drop-cast from volatile amine dispersions

Thin single walled carbon nanotube (SWNT) films have been fabricated by drop-casting from SWNT dispersions in the volatile organic solvent, n-butylamine. This solvent can be removed by a simple annealing step which leads to substantial improvements in both transparency and conductivity of the films. The key factor in this increase in conductivity is reduction of barriers in SWNT networks upon surfactant removal, leading to enhanced conduction by variable range hopping. Contributions to the increased conductivity also arise from a thermally activated current at temperatures above ∼225 K and a small metallic contribution which is visible at temperatures below ∼3 K.