Fabrication and electrical properties of all-printed carbon nanotube thin film transistors on flexible substrates

Abstract

In this manuscript, we developed a high-performance, printable and water-based semiconducting SCNT ink, and fabricated all-printed chemically functionalized CoMoCat 76 SCNT thin film transistors (TFTs) on flexible substrates via a suite of printing technologies. The metallic species in the pristine CoMoCat 76 SCNTs were effectively eliminated by organic radicals, and the functionalized SCNTs were characterized by UV-Vis-NIR spectroscopy and Raman spectra. The high quality, printable and water-based functionalized SCNT inks were obtained by tuning the ink ingredients, such as the concentrations of surfactants and additives. The printing methods we investigated include inkjet printing, aerosol jet printing and a hybrid with nanoimprinting. Large area source and drain electrode patterns were first fabricated on flexible substrates by a hybrid printing method, and then the optimal SCNT ink was printed on the channel of the TFT devices by ink-jet printing. Subsequently, the silver side-gate electrode and ion gel dielectric layer were deposited by aerosol jet printing. The all-printed flexible TFTs exhibited an effective mobility up to 1.5 cm² V⁻¹ s⁻¹ and an on/off ratio up to 4 × 10³. This work opens up a way to fabricate scalable and all-printed flexible electronics, and it is of benefit to generalize the practical applications of flexible electronics in the future.