Interfacial Failure in Flexible Electronic Devices

Flexible inorganic electronics with the delicate integration of stiff electronic films on soft substrate have attracted much attention recently. For the large mismatch of mechanical properties between the soft substrate and stiff electronic films in such devices, interfacial failures are always extremely dangerous. In this letter, we present theoretical analysis for the interfacial failures based on fracture mechanics and establish the criteria for the failure modes. It is found that the thin films always slip first and then transit to delamination from the substrate as the increasing of applied loading. The theoretical prediction is consistent with the experiment, which can guide the design and evaluate the reliability of flexible electronics.