Mechanical stability analysis of organic thin film transistors considering interfacial delamination

The mechanical characteristics of organic thin film transistor (OTFT) currently capture increasing researchers´ attentions for its advanced applications. Experiments have shown that the failures of the device during bending test highlight in the interfacial delamination of the top-electrode in recent literature. However, the mechanism of interfacial crack of the OTFT is still not clear. Aiming at this problem, the interfacial peeling of the top-electrodes, because the substrate is subjected to pure bending loading, is investigated using the finite element method combined with virtual crack closure technique (VCCT) with dummy nodes in this paper. The interfacial stresses and energy release rate (ERR) are introduced to determine crack position and facture propagation, considering the effects of key factors such as the geometrical dimensions and material properties. It is shown that the thinner and more compliant top-electrode as well as the thinner substrate can be adopted when design the stable and reliable OTFT devices. This work is expected to provide efficient method to improve mechanical stability of the OTFT.