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.