High Mobility, Low\nOff-Current, and Flexible Fiber-Based\na‑InGaZnO Thin-Film Transistors toward Wearable Textile OLED\nDisplays

Fiber-based organic light-emitting diodes (OLEDs) are\ngaining attention\nas promising candidates to achieve truly wearable textile displays\nbecause of their favorable electrical and mechanical characteristics.\nHowever, although fiber OLEDs have been developed into passive-matrix\ndisplays, it has not been possible to achieve active OLED operation\nbecause of the difficulty of realizing fiber-based thin film transistors\n(TFTs) with the proper electrical and mechanical performance at the\nsame time. Here, 1D cylindrical fiber-based IGZO TFTs, which simultaneously\nexhibit a high electrical performance and flexibility, are reported.\nTo address this trade-off relationship, four key stages of a novel\nfabrication process and unique device structures that suitable for\nthe thermal properties and cylindrical structure of the fiber were\napplied: (I) prethermal treatment, (II) partially patterned layers,\n(III) coplanar structure, and (IV) continuous postannealing (CPA)\nprocess. As a result, the fabricated fiber-based IGZO TFTs showed\nhigh mobility (8.6 cm<sup>2</sup>/(V s)) and low off-current (∼10<sup>–12</sup> A), comparable to that glass-based TFTs, as well\nas flexibility. Furthermore, based on these valid performances, it\nwas demonstrated that fiber phOLEDs could be driven by fiber-based\nIGZO TFTs using a wiring connection with Cu wire and Ag paste. The\nresults suggest that this may allow the potential fabrication of fully\ntextile AMOLED displays, integrated with TFTs.