Electrical Modeling of Active Layer Morphology Alterations in Response to the Applied Mechanical Strain in Organic Solar Cells

Thin-film organic solar cells are becoming in-creasingly interesting owing to their flexibility and ease of integration in many applications. Hence to further enhance the practical implementation, investigating the effects of mechanical deformation on the device's behavior is of high interest. This study proposes the electrical modeling of the effect of applied mechanical strain on the active layer morphology of organic solar cells. The effect of applied tensile strain is modeled by observing the variations in bimolecular recombination and the effective band gap of the active layer. A conventional bulk heterojunction organic solar cell, utilizing a P3HT :PCBM mixture as its active layer, is considered. Two-dimensional (2-D) drift-diffusion equations are solved using the finite element method in COMSOL Multiphysics. The results of this first-of-its-kind study show an enhancement of short circuit current, open circuit voltage, fill factor, and efficiency when the device is subjected to tensile strain, which is in good agreement with experimental observations.