Enhanced Photovoltaic Performance via Co-sensitization of Ruthenium (II)-Based Complex Sensitizers with Metal-Free Indoline Dye in Dye-Sensitized Solar Cells

Abstract

Co-sensitization is shown to be an effective method to improve the efficiency of dye-sensitized solar cells wherein ruthenium (ii)-based complex sensitizers (N749, N719) is co-sensitized with the metal-free indoline dye (D149), where photovoltaic efficiency of 5.40% is achieved by co-sensitized N749+D149 and efficiency of 4.94% is achieved by co-sensitized N719+D149. The assembled dye-sensitized solar cells were studied by UVvis absorption measurements of dye solutions, the absorption spectra of the dye-sensitized TiO 2 film along with co-sensitized TiO 2 film and current-voltage characteristics. The co-sensitized based device exhibits better photovoltaic performance compared to the devices fabricated from individual sensitizers. Upon optimization, the device made of co-sensitized N749+D149 yielded Jsc = 13.6 mA/cm 2 , Voc = 690 mV, FF = 0.576 and η = 5.40% and the device made of co-sensitized N719+D149 yielded Jsc = 13.3 mA/cm 2 , Voc = 660 mV, FF = 0.563 and η = 4.94%. This demonstrated that the performance of co-sensitized devices is improved from that of the devices sensitized with either N749 (4.56%), N719 (4.24%) or D149 (4.06%) under the same fabrication conditions.