Effect of anchoring groups number on the photovoltaic parameters in dye-sensitized solar cells

Abstract

Abstract We have developed a series of Ru sensitizers (GS16, GS17 and GS19) with molecular architecture containing a tridentate ligand with one, two and three anchoring groups and three thiocyanates. Furthermore, we have studied the effect of the number of carboxylic groups on photovoltaic properties. The absorption spectra of the novel sensitizers extended up to the red region (900 nm). The electrochemical studies reveal that the oxidation potentials are aligned below the iodine-based redox potential, feasible for easy regeneration, and the lowest unoccupied molecular orbital of all sensitizers lies above the TiO2 conduction band, which is favourable for easy electron injection. The overall efficiency (η) of the GS16, GS17 and GS19 is 1.13, 2.71 and 1.59% with short-circuit current (JSC) of 3.74 mA cm−2, 7.08 mA cm−2, 6.27 mA cm−2, open-circuit voltage (VOC) of 0.42 V, 0.54 V and 0.39 V and fill factor of 0.70, 0.70 and 0.65, respectively. The highest efficiency of 2.71% was observed in GS17, bearing the two anchoring groups compared to one and three carboxylic acid-containing sensitizers (GS16 and GS19). Theoretical studies are also examined and matched with the experimental data.