Three-Dimensional Fabrication of Carbon Nanotube-Conducting Polymer Composite Wires by Ink-Pen Growth method

S.K. Seol, D. Kim, S. Jung, W.S. Chang, Y.M. Bae
KERI(Korea Electrotechnology Research Institute), KR

Keywords: CNT/conducting polymer composite wire, ink-pen growth, high aspect ratio, site-specific positioning

Summary:

Carbon nanotube (CNT)/conducting polymers (such as polypyrrole (PPy), PEDOT:PSS [Poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate)], polyaniline (PANI)) composite are very interesting materials combining high conductivity and excellent mechanical properties.1 The potential applications of CNT/conducting polymer composite micro- and nanowires include bio and chemical sensors, electrochromic displays, field effect transistors, light emitting diodes and electrical interconnections. For such advanced applications, however, three-dimensional (3D) growth, site-specific positioning, and individual control of the wire characteristics are required. None of the fabrication techniques used so far - including lithography, template based synthesis, and electrospinning - can match all these requirements. Here, using ink-pen growth method,2 we demonstrate 3D fabrication of CNT/PEDOT:PSS composite wires with controlled dimensions, site-specific positioning and high aspect ratios. Individual micro- and nanowires are grown by controlled pulling of a micropipette (“Ink-pen”) filled with mixed solution (“Ink”) of CNT and PEDOT:PSS. The ink is released locally from the end of ink-pen and the solvent is evaporated at the same time, resulting in formation of CNT/PEDOT:PSS composite wires. We also investigate I-V characteristic of grown wires by concentration ratio of CNT and PEDOT:PSS included in the ink.