Effects of the terminal donor unit on the photovoltaic parameters of benzocarbazole-based dyes for DSSCs: DFT/TD-DFT investigations

In this paper, a computational study on five organic p-conjugated molecules based benzocarbazole (BC) is reported. These new dyes were characterize theoretically by density functional theory (DFT) and time-dependent (TD-DFT) approaches. Different electron side groups were introduced as a terminal donor to investigate their effects on the electronic structure; the HOMO, LUMO, free energy of electron injection (∆G inject ), free energy regeneration (∆G reg ), open circuit voltage (V oc ), the gap energy and UV–visible absorption spectra analysis of these dyes have been reported and discussed. The calculated results show that dye M3 with phenoxazine as a terminal donor groups can be used as a potential donor of electron in DSSCs, due to its best electronic and optical properties and good photovoltaic.