Exploring the effect of end-capped modifications of carbazole-based fullerene-free acceptor molecules for high-performance indoor organic solar cell applications

Organic solar cells (OSCs) have received much attention because of their versatile advantages including solution process ability, flexibility, transparency, and lightweight. Fullerene-free acceptor molecules are efficiently utilized in organic solar cells due to their perfect symmetry with donor polymer. In this study, modifications of fullerene-free acceptor molecules have been done using efficient end-capped units. Five new molecules have been designed and explored through DFT and TD-DFT approaches at MPW1PW91 method with 6-31G(d,p) level of theory. Analysis of frontier molecular orbitals, transition density matrix, open-circuit voltage, excitation and binding energies has been done for exploring the photovoltaic and opto-electric properties of the designed molecules. Electron and hole reorganization energies are also computed for examining the mobility of charge density in designed molecules. Results of different geometric analyses suggested that EC1 to EC5 are effective contributors for highly stable organic solar cells. Graphical abstract: [Figure not available: see fulltext.]