Conjugating pillararene dye in dye-sensitized solar cells

Summary The improvement of open-circuit voltage (VOC) is a crucial goal to develop efficient dye-sensitized solar cells (DSSCs). Here, conjugating pillar[5]arene dyes (PPI and PPII) are designed, synthesized, and applied in DSSCs. The presence of pillar[5]arene moiety in the dyes inhibits the dye aggregation and charge recombination in the DSSCs, leading to the enhancement of VOC. PPI with a single D-π-A backbone and a pillar[5]arene moiety achieves a VOC of 715 mV, which is much higher than the reference dye (VOC of 674 mV) with the same D-π-A backbone but no pillar[5]arene moiety. PPII with 2 D-π-A backbones also achieves a VOC of 746 mV and a much higher short-circuit photocurrent (JSC) than the reference dyes. In addition, the host-guest interaction can adjust the VOC and JSC by coupling dye with the imidazolium in electrolyte, as confirmed by the electrolyte engineering.