Dual use of anionic azobenzene derivative as dispersant and dopant for carbon nanotubes for enhanced thermal stability of transparent conductive films

摘要

Air- and thermally stable carbon nanotube (CNT)-based transparent conductive films have been developed by a facile wet-coating method using an anionic azobenzene derivative with sulfonate group that was synthesized by a simple one step process. The conductive film showed low sheet resistance (122 Omega/sq at T = 81%) without any post-treatment processes such as the removal of dispersant or acid treatment, because the azobenzene derivative served both dispersant and dopant roles in the CNT films. The conductive films showed constant sheet resistance under various thermal and environmental conditions, such as in air at room temperature over an 8-month period, in air at 250 degrees C for 1 h, and in vacuo at 100 degrees C for 1 h. This stability comes from the strong intermolecular interactions between the azobenzene derivative and CNT. Thermally less susceptible property of the azobenzene derived from the substituent size also reduces the thermal desorption of the azobenzene from the CNT surface, supporting the stability of transparent conductive films at relatively high temperatures. (C) 2019 Elsevier Ltd. All rights reserved.