Computational optimization and optical analysis of thin-film organic solar cells for high efficiency

This paper reports the computational investigation of two thin-film organic solar cell (TFOSC) structures which are based on two different species, i.e., fullerene-based material (PTB7:PCBM) and non-fullerene-based material (PIF8BT:PDI). Computational investigations are performed on the optimization of thickness for the active absorber layers because the major portion of the sunlight is absorbed in this area. The electrical parameters include the open-circuit voltage (V_oc), short-circuit current density (J_sc), fill factor (FF), and power conversion efficiency (η). The extracted modeling results indicate that 200 nm is sufficient to cover the visible spectrum range of photons within the investigation range of 150–400 nm. Moreover, the present study also highlights the optical analysis of the architecture, which shows the absorption of photons in the active region with various thicknesses. After the comparative analysis of the two structures, the results suggest that the structure based on fullerene is 0.97% more efficient than the non-fullerene-based structure. The highest conversion efficiency achieved with the fullerene-based scheme (FTO/PEDOT:PSS/PTB7:PCBM/PFN/Ag) was 4.79%, whereas the highest efficiency rate delivered by the non-fullerene scheme (FTO/PEDOT:PSS/PIF8BT:PDI/PFN/Ag) was 3.82%. The recorded results are in good agreement with the theoretical models and standard action.