Synergistic integration of Ni and vertically aligned carbon nanotubes for enhanced transport properties on flexible substrates

We report on the enhanced in-plane electrical and thermal transport properties of a novel hybrid material consisting of Ni and vertically aligned carbon nanotubes (VACNTs) on a flexible polycarbonate substrate. The Ni layer is integrated on the as-grown VACNTs by sputtering, and a non-intrusive laser-assisted dry transfer technique is adopted to prepare test strips that retain the aligned structure of as-grown VACNTs. First, we determine the in-plane electrical and thermal conductivity of intrinsic VACNTs. Then we confirm the significant transport property enhancement by repeating the same measurements with the Ni-VACNT hybrid material. Our systematic results reveal that the in-plane transport properties are highly dependent not only on the height of the VACNTs, but also on the thickness of the added Ni layer. We also conduct mechanical fatigue tests where the Ni-VACNT strips show a superior bendability under cyclic loading. Our results suggest that the synergistic combination of VACNTs and the Ni layer compensates for the anisotropic limitation of transport properties in VACNTs. This facile and cost-effective approach offers promise for application in next-generation flexible devices. (C) 2013 Elsevier Ltd. All rights reserved.