Eight novel diketopyrrolopyrrole (DPP)-based A-D-A-D-A structure molecules were designed for organic solar cells (OSCs) applications. In these molecules, the electron-deficient DPP and dicyanovinyl groups were used as the acceptor groups and different planar electron-rich groups were employed as the donor π-bridges. Applying the B3LYP/6-31G (d,p) and TD-B3LYP/6-31G (d,p) methods, the optoelectronic and charge transport properties were investigated. It turned out that the different π-bridges can tune effectively the frontier molecular orbital energy levels, band gap, and absorption spectra. Furthermore, the different π-bridges also affect the charge transport properties of the designed molecules. Our results suggest that the investigated molecules can serve as donor materials. Additionally, some investigated molecules can also be used as hole and/or electron transport materials for OSCs. Graphical abstract A series of novel A-D-A-D-A molecules are investigated systematically. The optical and electronic properties can be tuned effectively by the π-bridges. All derivatives can be used as donor materials for OSCs. Some designed molecules can be used as hole and/or electron transport materials. The different π-bridges do not significantly affect the stability of the molecules.
Keywords: Dicyanovinyl; Diketopyrrolopyrrole (DPP); Optoelectronic property; Organic solar cells (OSCs); Reorganization energy.