Comparison of triphenylamine based single and double branched organic dyes in dye-sensitized solar cells

A series of single and double branched organic dyes (1–4) utilizing two different acceptor groups, 2-cyanoacetic acid and rhodanine-3-acetic acid as anchoring moieties, were synthesized and characterized for their potential in dye sensitized solar cells (DSSCs). The DSSC based on sensitizer 3 has the best power conversion efficiency (3.51%) among all the devices assessed, which was 2 times higher than that of 1 with only one anchoring group. Compared to the 1–2 congeners with only one anchor, the dianchoring dyes 3–4 could suppress charge recombination more effectively and increase the electron injection efficiency, leading to a higher open-circuit voltage and short-circuit current.