Novel pyridoquinazolindone-containing triphenylamine dyes for dye-sensitized solar cells

Four novel "A-D-pi-A" pyridoquinazolinone-containing triphenylamine dyes were synthesized for dye-sensitized solar cell (DSSCs), which consist of triphenylamine as the electron donor, thiophene or C=C bond as pi-bridge, cyanoacrylic acid as the electron acceptor and pyridoquinazolinone as the auxiliary acceptor. Their photophysical, electrochemical properties and photovoltaic performance were investigated. Moreover, density functional theory (DFT) was performed for theoretical calculations. The results show that the incorporation of additional pyridoquinazolinone unit enables dyes with larger charge recombination resistance than the dyes with single pyridoquinazolinone unit, which benefits the increase of Voc. Besides, the introduction of thiophene bridge can broaden and red-shift the absorption region, which endows the dyes with better light-harvesting ability and subsequently brings about superior IPCE and Jsc. Therefore, dye with double pyridoquinazolinone units and thiophene bridge exhibits the best photoelectric conversion efficiency 5.19 % (Jsc = 11.71 mAcm(-2), Voc = 0.67 V, ff = 0.70).