| dc.description.abstract | Dye-Sensitized Solar Cell, (DSSC) is one of the hottest research topics in the photovoltaic technology, due to its low production cost, transparent, colorful, and can be flexible. In the past a couple of decades, there are many studies focus on increasing the photocurrent of DSSCs by structural design of the dye molecules. Nevertheless there are very few papers focus on enhancing the open-circuit voltage of DSSC through the design of the sensitizers’ structure. In this study, we investigate the effect of the dye structure on the open-circuit voltage of the corresponding DSSC. The strategy is to avoid the electrolyte to contact TiO2 surface to produce dark current. Five ruthenium based dyes coded SJW-B4, SJW-B8, SJW-B10, SJW-B17, and SJW-B18 in which thiophene derivatives were incorporated to extend the conjugation length of the ancillary ligand, or more electron-donating ability atom (O, S) or a bulky group was incorporated in the ancillary ligand, or add more alkyl chains on the terminal of the ancillary ligand. The results show that SJW-B18 with the ancillary ligand containing 4 butyl chains improves the coverage of TiO2, decreasing the electron recombination between the TiO2 and electrolyte. DSSC sensitized by SJW-B18 with I-/I3- electrolyte has the highest Voc and conversion efficiency. Furthermore, when Co(II)/Co(III) electrolyte was used, DSSC sensitized by SJW-B18 has the highest Voc of 833 mV. SJW-B18 has 4 butyl chains on its ancillary ligand, forming good coverage on TiO2 surface, avoiding the charge recombination between the TiO2 and electrolyte, reducing the dark current, therefore the corresponding DSSC has high Voc. | en_US |