Reliability modeling of thin films under mechanical and thermal loads for solar cell applications

The solar cell system has economic and environmental impacts that cause many researchers to investigate its capability in electrical system design. Designing and developing flexible electronic devices to be more reliable is still challenging in this field of industry. In this work we focus on studying mechanical and thermal behavior of conductive polymer and conducting transparent conductive oxide coated on flexible plastic substrate. Samples of Poly (3, 4-ethylenedioxythiophene) (PEDOT) with two different resistances (150O/□ and 225O/□) coated on polyethyleneterephthalate (PET) and Indium tin oxide (ITO) with two different resistances (60O/□Ω and 200O/□) coated on PET were used in experiments. Therefore, cycling bending, tensile loads, and damp heat tests were conducted on both thin films. PEDOT showed good mechanical properties with a small resistance change and no clear deformation or cracks that formed on the surface under mechanical loads. However, the resistance of ITO significantly increased due to clear cracks developed on its surface. At addition of electrical resistance the transparency of thin films was studied after a damp heat test. Further design of experiment approach was used to study the effect of different parameters.;Finite element analysis approach was used to predict stress developed in thin films (PEDOT&ITO) when subject to cyclic bending and tensile loads and the effect of thicknesses for both thin films on induced stresses. Furthermore, Finite element modeling results provided high agreement with experiments results. Artificial neural network used as a multi-dimensional curve fitting procedure to fit experimental data. Multi-dimensional neural network techniques were utilized to build different models between PCER and parameters. However, the artificial neural network model provides good accuracy results when compared with other classical techniques.