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. The optoelectronic properties of all these A₂–D–A₁–D–A₂-type molecules have been evaluated with the help of density functional theory along with its time-dependent approach. The proposed molecules exhibit reduced energy gaps compared to the reference molecule, which consequently results in red shifted absorption with higher maximum absorption wavelengths. 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.