Channel Cracking and Interfacial Delamination of Indium Tin Oxide (ITO) Nano-Sized Films on Polyethylene Terephthalate (PET) Substrates: Experiments and Modeling
- 30 Downloads
Our research objective was to obtain a fundamental understanding of how ITO thin films layered on flexible polyethylene terephthalate (PET) substrates fail due to tensile, shear, and bending loading conditions. In our approach, we employed a nonlinear finite-element (FE) approach coupled with dislocation-density crystalline and hypoelastic material models and fracture approaches tailored for channel (film) cracking and interfacial delamination. These predictions were validated with mechanical experiments and characterization at different physical scales. Failure to strain and fracture predictions were used to account for interrelated mechanisms, such as channel and interfacial cracking nucleation and propagation along cleavage planes, interfaces, and within layers. Our predictions indicate that interfacial delamination occurred when channel cracks transitioned to interfacial cracks at the ITO/PET interface for tensile loading conditions. Furthermore, the thin film system, when subjected to three-point bending and shear loading conditions was more resistant to failure in comparison to systems subjected to tensile loading conditions.
KeywordsThin film failure Indium tin oxide Delamination Nanosized
We gratefully acknowledge financial support from Eastman Chemical Company and the discussions with T. Smart, J. Dougherty, J. Li, and T. Floyd from Eastman Chemical Company on thin films are gratefully acknowledged; those discussions spurred our research in new directions. This work was performed in part at the Analytical Instrumentation Facility (AIF) at North Carolina State University, which is supported by the State of North Carolina and the National Science Foundation (award number ECCS-1542015). The AIF is a member of the North Carolina Research Triangle Nanotechnology Network (RTNN), a site in the National Nanotechnology Coordinated Infrastructure (NNCI).