A comparison of the electronic and photovoltaic properties of novel twin-anchoring organic dyes containing varying lengths of π-bridges in dye-sensitized solar cells

•Phenothiazine dyes with varying numbers of thiophene bridging units were synthesized.•DSSC fabricated with the dithiophene dye exhibited enhanced power conversion efficiency.•These results were supported by the decay curve of Voc, and IPCE.

Two novel donor acceptor π-conjugated (D–π–A) organic dyes have been engineered as sensitizers for applications in dye-sensitized solar cells. The derivatives of phenothiazine containing different numbers of thiophene units in the chromophore were synthesized to investigate the correlation between the number of π-bridge photovoltaic properties as photosensitizers for dye-sensitized solar cells. The organic dye with dithiophene units exhibited a higher molar extinction coefficient and more efficient electron injection from the dye to TiO2 conduction band leading to an improved light harvesting efficiency. The solar-to-electricity conversion efficiency of 7.3% in the case of the bis(dithienyl) bridged dye with an open-circuit voltage of 0.636 V and short-circuit photocurrent density of 18.692 m A cm−2, deriving from a higher absorption with respect to the mono (2,5-thienyl) containing dye, as conformed by incident photo-to-current conversion efficiency measurements.