title: Failure criterion of silver nanowire electrodes on a polymer substrate for highly flexible devices.
abstract: Nanomechanical characteristics of standalone silver nanowires (Ag NWs) are a key issue for providing a failure criterion of advanced flexible electrodes that are trending towards smaller radius of curvatures (ROCs). Through in-situ tensile and buckling tests of pentagonal Ag NWs, we demonstrated that the intrinsic fracture strain provides a significant criterion to predict the mechanical and electrical failure of Ag NW electrodes under various strain modes, because the decrease in fracture strain limits figure of merit of flexible devices. The Ag NW electrodes on a polymer substrate exhibited a strain-dependent electrical failure owing to the unique deformation characteristics with a size-dependent brittle-to-ductile transition of the five-fold twinned Ag NWs. All the Ag NWs greater than approximately 40 nm in diameter exhibited brittle fracture with a size-independent stress-strain response under tensile and buckling modes, which leads to the electrical failure of flexible electrodes at the almost same threshold ROC. Meanwhile, the higher ductility of Ag NWs less than 40 nm in diameter resulted in much smaller threshold ROCs of the electrodes due to the highly extended fracture strains, which can afford a high degree of freedom for highly flexible devices.
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology(KIST), Seoul 02792, Republic of Korea.|Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 03722, Republic of Korea.
authors.forename: Donggyun
authors.initials: D
authors.lastname: Kim
authors.affiliation: Advanced Analysis Center, Korea Institute of Science and Technology(KIST), Seoul 02792, Republic of Korea.|Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea.
authors.forename: Sung-Hoon
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul 03722, Republic of Korea.
authors.forename: Jong Hak
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Materials Science and Engineering, Korea University, Seoul 02841, Republic of Korea.
authors.forename: Jae-Chul
authors.initials: JC
authors.lastname: Lee
authors.affiliation: Advanced Analysis Center, Korea Institute of Science and Technology(KIST), Seoul 02792, Republic of Korea.
authors.forename: Jae-Pyoung
authors.initials: JP
authors.lastname: Ahn
authors.affiliation: Clean Energy Research Center, Korea Institute of Science and Technology(KIST), Seoul 02792, Republic of Korea.|Clean Energy &Chemical Engineering, KIST campus, University of Science and Technology (UST), Seoul 02792, Republic of Korea.
authors.forename: Sang Woo
authors.initials: SW
authors.lastname: Kim