1 Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA 2 Department of Material Science, University of Southern California, Los Angeles, California 90089, USA 3 Department of Chemistry, University of Southern California, Los Angeles, California 90089, USA § These authors contributed equally to this work.
Due to their excellent electrical properties and compatibility with room-temperature
deposition/printing processing, high-purity single-walled semiconducting carbon
nanotubes hold great potential for macroelectronic applications such as in
thin-film transistors and display back-panel electronics. However, the relative
advantages and disadvantages of various nanotubes for macroelectronics remains
an open issue, despite the great significance. Here in this paper, we report a comparative
and systematic study of three kinds of mainstream carbon nanotubes
(arc-discharge, HiPCO, CoMoCAT) separated using low-cost gel-based column
chromatography for thin-film transistor applications, and high performance
transistors—which satisfy the requirements for transistors used in active matrix
organic light-emitting diode displays—have been achieved. We observe a trade-off
between transistor mobility and on/off ratio depending on the nanotube diameter.
While arc-discharge nanotubes with larger diameters lead to high device mobility,
HiPCO and CoMoCAT nanotubes with smaller diameters can provide high
on/off ratios (> 106) for transistors with comparable dimensions. Furthermore,
we have also compared gel-based separated nanotubes with nanotubes separated
using the density gradient ultracentrifuge (DGU) method, and find that
gel-separated nanotubes can offer purity and thin-film transistor performance
as good as DGU-separated nanotubes. Our approach can serve as the critical
foundation for future carbon nanotube-based thin-film macroelectronics.