X-shaped organic dyes with a quinoxaline bridge for use in dye-sensitized solar cells

Two novel X-shaped organic sensitizers (FNE48 and FNE49) with a quinoxaline bridge have been designed and synthesized. The structural difference between the two sensitizers is the number of anchoring groups. The relationship between the chemical structures and their optoelectronic properties has been systematically investigated. It is found that a broader and more intense charge transfer band is observed for sensitizer FNE48, with a single anchoring group, in comparison to sensitizer FNE49, which contains twin anchoring groups. Consequently, a high power conversion efficiency (eta) of 6.2% is achieved for a dye-sensitized solar cell (DSSC) based on sensitizer FNE48 using a liquid electrolyte. Moreover, a eta of 5.2% is obtained for a quasi-solid-state DSSC based on sensitizer FNE48 and this remains at 100% of the initial value after continuous light irradiation for 1500 h.