Influence of position of auxiliary acceptor in D–A–π–A photosensitizes on photovoltaic performances of dye-sensitized solar cells
Several novel indoline dyes configured with donor–acceptor–bridge–acceptor (D–A–π–A) structures were designed and applied to organic dye-sensitized solar cells. These D–A–π–A dye molecules are composed of indoline (electron donating group), benzothiadiazole (BDT) (auxiliary acceptor), two furan rings (π-conjugated group), and 2-cyanoacrylic acid (electron accepting group). The influence of position of auxiliary acceptor in D–A–π–A organic sensitizer on the performance of photosensitize is investigated in detail. Calculated results show that the sensitizer could achieve a red-shifted absorption in long-wavelength region and a stronger absorption in short-wavelength region when the position of auxiliary acceptor changes from the donor to the acceptor. Moreover, among these dyes, WS-12, whose auxiliary acceptor nearing the 2-cyanoacrylic acid, possesses the better performance in terms of the charge transfer characteristics, lifetime of excited state as well as the vertical dipole moment when compared with WS-1 and WS-11. We hope that the present results could provide theoretical guidance for designing photosensitizes with higher efficiencies.