Aryl/hetero-arylethyne bridged dyes: the effect of planar pi-bridge on the performance of dye-sensitized solar cells

We have designed and synthesized three metal-free sensitizers consisting of dimethoxy-substituted triphenylamine as donor, cyanoacrylic acid as acceptor with planar pi-bridge. The photon to current conversion efficiency of these dyes were measured as sensitizers for DSSCs analysis. The results obtained from these experiments show that the overall conversion efficiency of D3 gave the highest overall efficiency 4.98% with short circuit current density (J(sc)) of 11.29 mA cm(-2), an open-circuit voltage (V-oc) of 0.637 V and a fill factor of 69.2% under standard global AM 1.5 solar conditions. In addition, the experimental results show that pi-conjugated bridge can extend the absorption of dye molecular and strong planarity (close-packing) can suppress the charge recombination at TiO2/electrolyte interface. Hence, the donor-pi bridge-acceptor architectures can generate a unidirectional current flow, to some extent, which can enhance the cell performance.