Carbon nanotube/indium tin oxide hybrid transparent conductive film: Effect of nanotube diameter

Hybrid transparent conductive films (TCFs) based on indium tin oxide (ITO) and carbon nanotubes (CNTs) are prepared through a sol-gel dip coating method. The effect of CNT diameter on optoelectrical properties of TCF is investigated. The surface roughness and grain size are decreased and the optical transmittance is increased with CNT diameter. The existence of bundles in smaller CNTs is the main reason for lower transmittance in these samples. In terms of electrical resistivity, the large diameter CNT incorporated ITO film shows lower sheet resistance than bare ITO film at high enough film thicknesses. It seems that the large diameter CNT incorporation in ITO matrix can remarkably reduce the microcrack formation, especially at higher thicknesses, and act as nanobridges when microcracks are formed. Furthermore, the sensitivity of ITO film to thermal cycling is dramatically enhanced with these CNTs. In addition, the figure of merit of ITO film is considerably improved with large diameter CNT incorporation. (C) 2014 Elsevier B.V. All rights reserved.