Π SPACER EFFECT IN BENZIMIDAZOLE- QUINOLINE DONOR CONFIGURATION TO EXPLORE VISIBLE PHOTON ABSORPTION FOR DYE-SENSITIZED SOLAR CELLS.

[Display omitted] • A novel NSGDs/TiO 2 S-scheme heterojunction was successfully constructed. • TiO 2 possesses an urchin-like morphology with open mesoporous structure. • NSGDs offers better light absorption and photo-induced charge carriers' separation. • S-scheme heterojunction exhibits excellent photoactivity for toluene removal. In this study, we have considered a range of metal-free organic dyes with benzimidazole incorporated quinoline donors (BZQ) were designed with the configuration of Donor-Donor-π spacer-Acceptor (D-D-π-A). The impact of various π-spacer groups on their performance in dye-sensitized solar cells (DSSCs) was analyzed. The utilization of density functional theory (DFT) and time-dependent DFT (TD-DFT) methods has been employed in the examination of various aspects of electronic and absorption properties. The electronic absorption spectrum exhibits a red shift when the π spacer is increased, at the same time the energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) was reduced. Theoretical calculations of these dyes demonstrated that altering the π-spacer group can result in several beneficial effects on the photovoltaic performance. [ABSTRACT FROM AUTHOR]