Anthracene Organic Sensitizer with Dual Anchors for Efficient and Robust Dye-Sensitized Solar Cells

Two dyes DY1 and DY2 featuring 1,2-di(anthracene-9-yl)ethyne as an extended π-conjugated spacer and an N, N -diarylamino group as the donor have been designed and synthesized for application in dye-sensitized solar cells. On the other side of 1,2-di(anthracene-9-yl)ethyne, DY1 contains one carboxylic acid as the anchoring group at 10-position of anthracene, whereas the structural analogue DY2 has dual carboxylic acid groups at 4, 5-positions of anthracene as the anchors for binding to TiO 2 . With the introduction of dual carboxyl anchors, the higher dipole moment of the molecule may induce relatively high local I – concentration at the interface to reduce the oxidized dye (D + ); thus, the DY2 -based device has the highest short-circuit current ( J SC ). For open-circuit voltage ( V OC ), both DY1 - and DY2 -based devices have close V OC owing to their structures resembling CW6 . For the DY2 -based device, the power conversion efficiency of DSCs was η = 6.96% under simulated one-sun AM 1.5 G illumination with J SC = 13.08 mA cm –2, V OC = 0.73 V, and FF = 0.73, which is considerably higher than that of the DY1 -based device with η = 5.71%, J SC = 10.70 mA cm –2, V OC = 0.72 V, and FF = 0.74, whereas the reference dye CW6 exhibited a cell performance of η = 6.96%, J SC = 11.50 mA cm –2, V OC = 0.78 V, and FF = 0.78. Besides, the dual anchoring dye, DY2 -based device exhibited better stability than the others.