title: Ambient atmosphere-processable, printable Cu electrodes for flexible device applications: structural welding on a millisecond timescale of surface oxide-free Cu nanoparticles.
abstract: Recently, various functional devices based on printing technologies have been of paramount interest, owing to their characteristic processing advantages along with excellent device performance. In particular, printable metallic electrodes have drawn attention in a variety of optoelectronic applications; however, research into printable metallic nanoparticles has been limited mainly to the case of an environmentally stable Ag phase. Despite its earth-abundance and highly conductive nature, the Cu phase, to date, has not been exploited as an ambient atmosphere-processable, printable material due to its critical oxidation problem in air. In this study, we demonstrate a facile route for generating highly conductive, flexible Cu electrodes in air by introducing the well-optimized photonic sintering at a time frame of 10(-3) s, at which the photon energy, rather than conventional thermal energy, is instantly provided. It is elucidated here how the surface oxide-free, printed Cu particulate films undergo chemical structural/microstructural evolution depending on the instantly irradiated photon energy, and a successful demonstration is provided of large-area, flexible, printed Cu conductors on various substrates, including polyimide (PI), polyethersulfone (PES), polyethylene terephthalate (PET), and paper. The applicability of the resulting printed Cu electrodes is evaluated via implementation into both flexible capacitor devices and indium-gallium-zinc oxide (IGZO) flexible thin-film transistors.
authors.affiliation: Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), Daejeon 305-600, Republic of Korea. youngmin@krict.re.kr sjeong@krict.re.kr.
authors.forename: Sang-Jin
authors.initials: SJ
authors.lastname: Oh
authors.forename: Yejin
authors.initials: Y
authors.lastname: Jo
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Lee
authors.forename: Sun Sook
authors.initials: SS
authors.lastname: Lee
authors.forename: Young Hun
authors.initials: YH
authors.lastname: Kang
authors.forename: Hye-Ji
authors.initials: HJ
authors.lastname: Jeon
authors.forename: Song Yun
authors.initials: SY
authors.lastname: Cho
authors.forename: Jin-Seong
authors.initials: JS
authors.lastname: Park
authors.forename: Yeong-Hui
authors.initials: YH
authors.lastname: Seo
authors.forename: Beyong-Hwan
authors.initials: BH
authors.lastname: Ryu
authors.forename: Youngmin
authors.initials: Y
authors.lastname: Choi
authors.forename: Sunho
authors.initials: S
authors.lastname: Jeong