Theoretical study of D-A-π-A organic dye molecules in dye-sensitized solar cells

Geometry optimization of two organic dye molecules WS-3 and WS-4 with D-A-π-A type was carry out by density functional theory, and the stable structures of WS-3 and WS-4 were obtained. In order to study the properties of photoelectric conversion between WS-3, WS-4 and TiO₂, WS-3 and WS-4 were dock with TiO₂ using the docking software, and WS-3 TiO₂ and WS-4 TiO₂ were obtained. Then the structures of WS-3 TiO₂ and WS-4 TiO₂ was optimized further, and stable structures of WS-3 TiO₂ and WS-4 TiO₂ in the ground state and in the excited state were obtained. Finally, frontier molecular orbitals of WS-3, WS-4, WS-3 TiO₂ and WS-4 TiO₂ were computed and net charges of TiO₂ were analyzed. The calculated results are in good agreement with the experimental results. We hope some results obtained may be useful as theoretical references for designing this kind of compounds. (authors)