Understanding the mechanisms that change the conductivity of damaged ITO-coated polymeric films: A micro-mechanical investigation
KAUST DepartmentPhysical Sciences and Engineering (PSE) Division
Mechanical Engineering Program
Composite and Heterogeneous Material Analysis and Simulation Laboratory (COHMAS)
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AbstractDegradation from mechanical loading of transparent electrodes made of indium tin oxide (ITO) endangers the integrity of any material based on these electrodes, including flexible organic solar cells. However, how different schemes of degradation change the conductivity of ITO devices remains unclear. We propose a systematic micro-mechanics-based approach to clarify the relationship between degradation and changes in electrical resistance. By comparing experimentally measured channel crack densities to changes in electrical resistance returned by the different micro-mechanical schemes, we highlight the key role played by the residual conductivity in the interface between the ITO electrode and its substrate after delamination. We demonstrate that channel cracking alone does not explain the experimental observations. Our results indicate that delamination has to take place between the ITO electrode and the substrate layers and that the residual conductivity of this delaminated interface plays a major role in changes in electrical resistance of the degraded device. © 2014 Elsevier B.V.
SponsorsFunding for this study was provided by KAUST-OCRF. The authors are grateful to King Abdullah University of Science and Technology for its financial support (AEA Round 3 project "Hierarchically-based Adaptive and Flexible Electronic Energy Harvesting Membranes for Large Surface Area Deployment").