Computational modeling of oligothiophenes‐based donor molecules to boost optoelectronic attributes of organic solar cells

Abstract The computational modeling of seven oligothiophene‐based donor molecules (TZ1–TZ7) designed by acceptor modification at the terminal position of the literature molecule (TZR) were discussed for organic solar cells (OSCs). DFT simulations using B3LYP/def2svp levels were performed to study the optoelectronic, and PV properties of TZ1–TZ7. A range of essential aspects for efficient small donor molecules like open circuit voltages ( V OC ), excitation energy ( E x ), dipole moment (μ), density of state (DOS), absorption maxima ( λ max ), transition density matrix (TDM), binding energy ( E b ), and frontier molecular orbitals (FMOs) of TZ1–TZ7 and TZR have also been investigated. DOS and FMOs analysis revealed a reduced energy gap ( E g ) and effective charge transfer (CT) in the TZ1–TZ7 molecules. The absorption spectra were examined using TD‐DFT. Due to smaller E g , E b , E x , and higher λ max , μ , the TZ1–TZ7 molecules exhibit remarkable optoelectronic properties. The computed V OC (0.969–1.189) and fill factor (0.886–0.897) for TZ1–TZ7 lead to improved power conversion efficiency (PCE) ranging from 14.05% to 17.60%. All compounds are strongly recommended for fabricating efficient OSCs with excellent PV properties. The current work is a step towards environmentally friendly organic PV and will pave the way for future structural engineering research for the efficient material design of OSCs.