Terminal Group Engineering in Small Molecule Acceptors: A First-Principles Approach to Improving Organic Solar Cell Performance

Abstract

In this study, eight new compounds have been designed to enhance the performance of organic solar cells (OSCs) using an end-capped modification strategy. Fullerene-free OSCs demonstrate excellent efficiency, positioning them as promising materials for photovoltaic applications. Optoelectronic properties of all these A 2 -D-A 1 -D-A 2 type molecules have been evaluated with the help of density functional theory (DFT) along with its time-dependent approach. All the proposed molecules possess low energy gap of 2.28-1.82 eV as compared to the reference molecule (2.30 eV). λ max values of all designed molecules are also higher (480-567 nm and 487-580 nm) in the gas and solvent (chloroform) phases respectively as compared to reference molecule (477 nm). To validate the optoelectronic characteristics of all the designed compounds, we have analyzed their frontier molecular orbitals, molecular electrostatic potential, charge transfer rate, reduced density gradient, absorption parameter, transition density matrix etc. These findings corroborate the superiority of the newly designed compounds as potential building blocks for OSCs with improved performance.