Role of chenodeoxycholic acid as co-additive in improving the efficiency of DSSCs

Abstract Dye sensitized solar cells (DSSCs) are the third generation photovoltaics that convert solar radiation into electricity. DSSCs have been widely studied due to their low cost and ease of fabrication. In this study, TiO2 photoanodes have been sensitized with organic dyes RhB and D149 and their performance was compared with conventional N719 sensitized photoanode. Further, the consequences of addition of chenodeoxycholic acid (CDA) on the performance of DSSCs sensitized with RhB, D149 and N719 dyes were analyzed. The photoanodes were characterized using FESEM, EDXs and XRD techniques. To reduce the cost of DSSCs, Graphite from HB pencil along with PEDOT:PSS (Gr-PEDOT) was used as catalytic material instead of expensive platinum in counter electrode. The electrocatalytic activity of prepared counter electrode was investigated by cyclic voltammetry. The performance of DSSCs was investigated by I-V characteristic measurement and Electrochemical Impedance Spectroscopy. The photo conversion efficiency of RhB, D149 and N719 sensitized DSSCs were found to be 1.42%, 6.67% and 6.34% respectively. At optimized condition, the addition of CDA in dye solution remarkably increased the performance of RhB, D149 and N719 sensitized DSSCs by 23.24%, 15.74% and 10.41% respectively. The electrochemical impedance spectroscopy has been analyzed in terms of Nyquist plot and an equivalent circuit has been modelled to find out series resistance, resistance due to redox reaction at counter electrode and charge transfer resistance at TiO2/dye/electrolyte interface.