Mechanical testing and analysis of polymer based flexible solar cell and full cell packaging

Polymer-based organic photovoltaic systems hold the promise for a cost-effective, lightweight solar energy conversion platform, which could benefit from simple solution processing of the active layer. However, few researchers have studied the mechanical properties of solar cell packaging, which can strongly affect the lifetime of the photovoltaic module. Therefore, we are motivated to study how the packaging structure and associated materials affect the reliability. In this research, the solar cell package, which is a five-layer structure where solar cell photo-reactive material printed on a polymer substrate, is presented. Additionally, there are two electrode layers and a coverage layer. Tests have already been conducted by a unique micro tester with small load high deformation resolution. Both layers and the overall package have undergone uniaxial tensile test. What we have found are as follows: 1) coverage, photo-reactive and substrate layers exhibit high ductility, the elongation at break of these layers are around 20%; 2) the strength and elongation of photo-reactive layer is the highest; 3) the delamination occurs earlier than the final collapse, showing that the bonding can be an issue in the process development; 4)The elongation of two electrode layers are 0.2% and 0.5%, which are the weakest part of the overall package. SEM method has been adopted to investigate the microstructure of overall packaging and each layer, the smooth and flat fracture surface results in low elongation property of the electrode material.