The role of the AC signal on the dielectrophoretic assembly of carbon nanotubes across indium tin oxide electrodes

Abstract

Multi-walled carbon nanotubes (MWCNTs) can be aligned along electric field lines between transparent electrodes to form a conductive network. In this work, MWCNTs were successfully deposited across indium tin oxide (ITO) electrodes using dielectrophoretic (DEP) force. For the first time, the deposition of MWCNTs across ITO electrodes separated by a distance of 50 μm is demonstrated to form an aligned network. The role of the AC signal amplitude, frequency, and duration is investigated experimentally. We found that the alignment was improved as the frequency increases (>105 Hz), while the minimum amplitude per the unit distance to deposit MWCNTs across ITO electrodes was 0.2 V/μm. The deposition process is observed in real-time using optical microscopy, and the aligned MWCNTs are observed with FeSEM spectroscopy. The study also investigates the resistivity, density and length of the aligned MWCNTs as a function of time. The deposition of MWCNTs across transparent electrodes using a room temperature method that requires a simple setup has potential use in future transparent electronics.