Facile and low-cost length sorting of single-wall carbon nanotubes by precipitation and applications for thin-film transistors

Published

February 14, 2016

Author(s)

Jeffrey Fagan, Hui Gui, Chongwu Zhou, Bilu Liu, Haitian Chen, Ming Zheng

Abstract

Semiconducting single-wall carbon nanotubes (SWCNTs) with long lengths are highly desirable for many applications such as thin film transistors and circuits. Previous reported length sorting techniques usually require sophisticated instrumentations and are hard to scale up. In this paper, we report for the first time a general phenomenon of length-dependent precipitation of surfactant-dispersed carbon nanotubes by polymers, salts, and their combinations. Polyelectrolytes such as polymethacrylate (PMAA) and polystyrene sulfonate (PSS) are found to be especially effective on cholate and deoxycholate dispersed SWCNTs. By adding PMAA to these nanotube dispersions in a stepwise way, we have achieved nanotube precipitation in a length-dependent order: first nanotubes with average length of 650 nm, and then successively of 450 nm, 350 nm, and 250 nm. Similar effect of nanotube length sorting has also been observed for PSS. To demonstrate the utility of the length fractionation, the 650-nm-long nanotube fraction was subjected to aqueous two-phase separation to obtain semiconducting enriched nanotubes. Thin-film transistors fabricated with the resulting semiconducting SWCNTs showed carrier mobility up to 18 cm2/(Vs) and on/off ratio up to 107. Our result sheds new light on the phase behavior of aqueous nanotube dispersions under high concentrations of polymers and salts, and offers a facile, low-cost, and scalable method to produce length sorted semiconducting nanotubes for macroelectronics applications.

Citation

Nano Research

Pub Type

Journals

Keywords

carbon nanotubes, length sorting, polymer precipitation

Citation

Fagan, J. , Gui, H. , Zhou, C. , Liu, B. , Chen, H. and Zheng, M. (2016), Facile and low-cost length sorting of single-wall carbon nanotubes by precipitation and applications for thin-film transistors, Nano Research (Accessed October 8, 2025)