Oh, Hyunuk Kim, Hayun Yoo, Hyunjun Park, Boik Chung, Seungjun Lee, Byeongmoon Hong, Yongtaek 2024-01-19T14:00:21Z 2024-01-19T14:00:21Z 2022-01-10 2021-09-15 1944-8244 https://pubs.kist.re.kr/handle/201004/116462 Random networks of single-walled carbon nanotubes (SWCNTs) offer new-form-factor electronics such as transparent, flexible, and intrinsically stretchable devices. However, the long-standing trade-off between carrier mobility and on/off ratio due to the coexistence of metallic and semiconducting nanotubes has limited the performance of SWCNT-random-network-based thin-film transistors (SWCNT TFTs), hindering their practical circuit-level applications. Methods for high-purity separation between metallic and semiconducting nanotubes have been proposed, but they require high cost and energy and are vulnerable to contamination and nanotube shortening, leading to performance degradation. Alternatively, additional structures have been proposed to reduce the off-state current, but they still compromise carrier mobility and suffer from inevitable expansion in device dimensions. Here, we propose a density-modulated SWCNT network using an inkjet-printing method as a facile approach that can achieve superior carrier mobility and a high on/off ratio simultaneously. By exploiting picoliter-scale drops on demand, we form a low-density channel network near the source and drain junctions and a high-density network at the middle of the channel. The modulated density profile forms a large band gap near the source and drain junctions that efficiently blocks electron injection under the reverse bias and a narrow band gap at the high-density area that facilitates the hole transport under the on-state bias. As a result, the density-modulated SWCNT TFTs show both high carrier mobility (27.02 cm(2) V-1 s(-1)) and a high on/off ratio (>10(6)). We also demonstrate all-inkjet-printed flexible inverter circuits whose gain is doubled by the density-modulated SWCNT TFTs, highlighting the feasibility of our approach for realizing high-performance flexible and conformable electronics. English American Chemical Society Inkjet-Printing-Based Density Profile Engineering of Single-Walled Carbon Nanotube Networks for Conformable High-On/Off-Performance Thin-Film Transistors Article 10.1021/acsami.1c11891 1 ACS Applied Materials & Interfaces, v.13, no.36, pp.43163 - 43173 ACS Applied Materials & Interfaces 13 36 43163 43173 scie scopus 000697282300079 2-s2.0-85115634042 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Science & Technology - Other Topics Materials Science Article single-walled carbon nanotube thin-film transistor channel density modulation energy band engineering inkjet printing on/off ratio