Organic solar cells have gained significant attention in recent years due to their properties of having low material costs, being lightweight, and undergoing high-throughput roll-to-roll production. However, their low efficiency and stability remain major challenges. Through our study, we aimed to address these issues by optimizing the optical and structural properties of the active layers to enhance performance and stability.
Here, we investigated how optical interference impacts device performance. Solar cell efficiency is influenced by various factors, including the materials used within their structures. To analyze the impact of structural geometry, we used bulk heterojunctions with P3HT as the donor layer and PCBM as the acceptor layer, forming the active layers. We examined various computed optical properties, such as the intensity of optical electric fields, the generation rate, absorption profiles inside the device, and reflection within the device. Additionally, we calculated the short-circuit current density concerning the active layers and found a high value of 11.35 mA/cm² for P3HT:PCBM active solar cells, which corresponds to the high absorption within the device structure. High performance was achieved in the case where high absorption was localized within the active-layer cells using the finite element method. The numerical simulation, conducted with COMSOL Multiphysics software, shows a strong correlation with published experimental data.