Improved Uniformity and Processability of Inkjet-Printed Single-Walled Carbon Nanotube Thin-Film Transistor by Introducing Cellulose Dispersant

Abstract

Solution-processed thin-film transistors (TFTs) based on single-walled carbon nanotubes (SWCNTs) hold great potential for next-generation electronics owing to their remarkable electrical, mechanical, and optical characteristics. However, challenges in efficiently dispersing SWCNTs hinder scalable fabrication. Conventional methods using surfactants improve SWCNT dispersion but lead to degradation of device performance due to increased contact resistance between the SWCNTs. Furthermore, the surfactant removal process induces unexpected characteristic nonuniformity by residual surfactant and network impairment. Here, we propose a facile and effective strategy for achieving superior performance uniformity in inkjet-printed SWCNT TFTs by using cellulose as a dispersant for SWCNTs. Cellulose-based SWCNT ink exhibits excellent dispersibility and stability, preserving the intrinsic electronic properties of SWCNTs while enabling optimal droplet formation for inkjet printing by adjusting the cellulose concentration. Based on the thermal decomposition characteristics of cellulose, we form a uniform SWCNT random network channel without affecting the nanotube network by selectively removing cellulose through a simple annealing process. As a result, the SWCNT TFTs fabricated on a 4-in. wafer substrate show significant improvements in characteristic uniformity, with a reduction of over 35% in performance variation, and exhibit strengths in switching performance compared to conventional surfactant-based SWCNT TFT fabrication methods.