Tuning of optoelectronic and charge transport properties of D–π–A diketopyrrolopyrrole-triphenylamine derivatives for organic solar cells application

Abstract

A series of D–π–A diketopyrrolopyrrole-triphenylamine-based molecules have been designed for organic solar cells (OSCs) applications. Their optical, electronic, and charge transport properties have been systematically investigated by applying density functional theory (DFT) and time-dependent DFT (TD-DFT) methods. It turned out that the vertical electronic transitions are characterized as intramolecular charge transfer. The calculated results show that the energetic driving force (ΔEL-L), adiabatic ionization potential (IPa), adiabatic electron affinity (EAa), and absorption spectrum can be tuned effectively by the introduction of different conjugate π-bridges. The designed molecules can serve as donor materials with smaller band gaps and intense absorption spectra, which is favourable for improving the efficiency of OSCs. Our results suggest that the designed molecules can provide match well with the typical fullerene acceptors PC61BM, bisPC61BM, and PC71BM. In addition, the designed molecules can be used as promising both eletron and/or hole transport materials. Furthermore, the different conjugate π-bridges do not significantly affect the stability of these molecules.