Self-Assembly by Coordination with Organic Antenna Chromophores for Dye-Sensitized Solar Cells.

The development of new sensitizers and new sensitization methods is one of the important means to enhance the conversion efficiency of DSSCs, the ultimate goal is to broaden the spectral response of dyes, reduce electron recombination, suppress dye aggregation. In this study, we have developed a series of new self-assembly dyes and applied in DSSCs. We prepared two organic antenna chromophores S1 and S2, and coordinated them with two acceptors A1 and A2 via zinc to construct A-Zn-S series self-assembled dyes. This method is very simple and feasible, and can avoid the complex synthesis steps of traditional dyes, the results show that the light-harvesting ability of devices can be improved and charge recombination can be reduced by adjusting the structures of the antenna chromophores and acceptors. The device of A2-Zn-S1 gived a PCE of 4.25%, which was higher than those of A1-Zn-S1 (3.88%), A1-Zn-S2 (3.21%) and A2-Zn-S2 (3.52%), the main reason is that the different coordination combinations between the antenna chromophore and the acceptor make a great difference in Voc and Jsc. The device based on A2-Zn-S1 showed a high Voc of 632 mV and a high Jsc of 9.54 mA cm-2, one reason is that S1 has better spectral responsiveness, another reason is that A2 has better steric resistance effectively reduces charge recombination. Besides, the IR indicates that these self-assembly dyes anchored on TiO2 surface by bicarboxyl anchoring group, it is also very beneficial for improving the performance of dyes.