title: Nano-branched transparent conducting oxides: beyond the brittleness limit for flexible electrode applications.
abstract: Although the performance of transparent conducting oxides based on bixbyite In(2)O(3) (Sn doped In(2)O(3): ITO) and wurtzite ZnO (Al, In, and Ga doped ZnO) is sufficient in conventional optoelectronic devices, their flexibility remains insufficient for demands in mobile and foldable electronics generation. A lot of alternative materials such as metallic nanowires and carbon based nano-structures have been tried for transparent flexible electrodes, but poor thermal stability of metal nanowires and limits in conductivity of carbon based nano-structures are still waiting for permanent solutions. Here, we show that the cross-linked ITO nano-branches have superior mechanical flexibility compared to ITO bulk film without any cracks even with a bending radius of 0.1 cm. Moreover, for equivalent sheet resistivity, the ITO nano-branches exhibit optical transmittance comparable to that of commercial metallic nanowires (such as Ag and Cu in the visible spectrum) but show far superior thermal stability in conductivity without any degradation even at a temperature of 200 °C and a humidity of 90%.
authors.affiliation: Department of Materials Science and Engineering and Division of Advanced Materials Science, Pohang University of Science and Technology, Pohang, 790-784, Korea.
authors.forename: Hak Ki
authors.initials: HK
authors.lastname: Yu
authors.forename: Sungjun
authors.initials: S
authors.lastname: Kim
authors.forename: Bonhyeong
authors.initials: B
authors.lastname: Koo
authors.forename: Gwan Ho
authors.initials: GH
authors.lastname: Jung
authors.forename: Bola
authors.initials: B
authors.lastname: Lee
authors.forename: Juyoung
authors.initials: J
authors.lastname: Ham
authors.forename: Jong-Lam
authors.initials: JL
authors.lastname: Lee