Failure mechanics of organic-inorganic multilayer permeation barriers in flexible electronics

Organic-inorganic multilayer permeation barriers are emerging as a promising solution to the stringent barrier requirement of flexible electronics. Yet the mechanical failure of the multilayer permeation barriers could be fatal to their barrier performance. We study two co-evolving failure mechanisms of the multilayer permeation barriers under tension, namely, the cracking of the inorganic oxide layer and the delamination along the oxide-organic interface, using computational modeling. An effective driving force for the oxide layer cracking is determined, which decreases as the oxide-organic interfacial adhesion increases. Emerging from the study is a simple but effective design to enhance the deformability of multilayer permeation barriers by applying a thin protective coating. Further studies show that strong adhesion of the coating-oxide interface is crucial for the coating performance. The results from this study provide quantitative guidance for the material selection and structural optimization of organic-inorganic multilayer permeation barriers of high mechanical durability. (C) 2010 Elsevier Ltd. All rights reserved.