title: Improving mechanical fatigue resistance by optimizing the nanoporous structure of inkjet-printed Ag electrodes for flexible devices.
abstract: The development of highly conductive metallic electrodes with long-term reliability is in great demand for real industrialization of flexible electronics, which undergo repeated mechanical deformation during service. In the case of vacuum-deposited metallic electrodes, adequate conductivity is provided, but it degrades gradually during cyclic mechanical deformation. Here, we demonstrate a long-term reliable Ag electrode by inkjet printing. The electrical conductivity and the mechanical reliability during cyclic bending are investigated with respect to the nanoporous microstructure caused by post heat treatment, and are compared to those of evaporated Ag films of the same thickness. It is shown that there is an optimized nanoporous microstructure for inkjet-printed Ag films, which provides a high conductivity and improved reliability. It is argued that the nanoporous microstructure ensures connectivity within the particle network and at the same time reduces plastic deformation and the formation of fatigue damage. This concept provides a new guideline to develop an efficient method for highly conductive and reliable metallic electrodes for flexible electronics.
authors.affiliation: Institute for Applied Materials, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Byoung-Joon
authors.initials: BJ
authors.lastname: Kim
authors.forename: Thomas
authors.initials: T
authors.lastname: Haas
authors.forename: Andreas
authors.initials: A
authors.lastname: Friederich
authors.forename: Ji-Hoon
authors.initials: JH
authors.lastname: Lee
authors.forename: Dae-Hyun
authors.initials: DH
authors.lastname: Nam
authors.forename: Joachim R
authors.initials: JR
authors.lastname: Binder
authors.forename: Werner
authors.initials: W
authors.lastname: Bauer
authors.forename: In-Suk
authors.initials: IS
authors.lastname: Choi
authors.forename: Young-Chang
authors.initials: YC
authors.lastname: Joo
authors.forename: Patric A
authors.initials: PA
authors.lastname: Gruber
authors.forename: Oliver
authors.initials: O
authors.lastname: Kraft