Theoretical investigation of Ga-corrole based dyes with different spatial structure for dye-sensitized solar cells

In order to investigate the effect of spatial arrangement of donor-acceptor group on gallium corroles for dye sensitized solar cells (DSSCs), this work had designed three new gallium corrole dye isomers C1-3 based on Ga-corrole dye C0. Their geometric structures, electronic structures, optical properties, intramolecular charge transfer (ICT) characteristics and the interactions with TiO2 clusters had been examined by using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. The results showed that the C1-3 dye molecules have good planarity, suitable HOMO-LUMO energy gap and strong UV-visible light absorption. Moreover, the dye molecule C2 has better charge separation and more favorable intramolecular charge transfer, showing that it is more helpful to improve the intermolecular charge transfer of gallium corrole dyes when the electron donor and acceptor are linked at the parallel meso-positions of the corrole macrocycle.