End-group modification of terminal acceptors on benzothiadiazole-based BT2F-IC4F molecule to establish efficient organic solar cells

In this study utilizing an end-capped modification approach seven novel molecules were created to improve the working of OSCs. Fullerene-free organic solar cells (OSCs) have a high potential to be used as promising photovoltaic devices due to their high efficiency and extended life span. Optoelectronic properties of all these A2-D-A1-D-A2 type molecules were evaluated with the help of density functional theory (DFT) along with its time-dependent approach. Proposed molecules possessed low band gap of 2.06–2.14 eV as opposed to the reference. The λmax values of designed molecules were also higher (705–744 nm and 742–781 nm in the gas and solvent (chloroform) phases respectively) as compared to BT2F-IC4F (reference molecule) having λmax at 702 nm in the gaseous phase and 739 nm in chloroform (CF) phase. The frontier molecular orbital, molecular electrostatic potential, density of states, and transition density matrix analyses were performed for validating the optoelectronic properties of created compounds. Open circuit voltage (Voc) of the formulated molecules except BT2F-U7 was also significantly improved; 1.07–1.41 eV compared to 1.24 eV of the reference. These findings corroborate the superiority of the newly designed compounds as potential building blocks for enhanced OSCs.