Physicochemical insights and in silico designing of new fullerene-free acceptor molecules for highly efficient and stable organic solar cells

A rational design of efficient low-band-gap non-fullerene acceptors for high-performance organic solar cells (OSCs) remains challenging. The main challenge is to design new materials with narrow band gap and high power conversion efficiency. Herein, efforts are made to design new acceptor materials (JA1–JA4) by end-capped modifications of a recently synthesized acceptor molecule (IDT-ED-4F). Density functional theory (DFT) and time dependent DFT (TDDFT) are used to examine the structure–property relationship and opto-electronic properties. Different geometric properties like transition density matrix, placement of frontier molecular orbitals, and open circuit voltage of the designed molecules are examined and verified through quantum chemical techniques. Light absorption properties of newly designed materials are also explored through a TDDFT approach. Low reorganization energy of electrons and holes with good values of open circuit voltage are achieved using molecules JA1–JA4 with PM6 donor polymer. Outcomes of different analyses indicate that the designed molecules should be effective contributors to high-performance OSC applications.