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 pi-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 TiO2. 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 opencircuit 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 eta = 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 eta = 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 eta = 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.