Influence of the benzo[d]thiazole-derived π-bridges on the optical and photovoltaic performance of D–π–A dyes

New metal-free organic sensitizers containing a benzo[d]thiazole or phenyl unit as the π-conjugated system, a triphenylamine as an electron donor, and a cyanoacrylic acid moiety as an electron acceptor were synthesized and used for dye-sensitized solar cells. Photophysical and electrochemical properties of these dyes were investigated, and their performances as sensitizers in solar cells were measured. The introduction of a benzo[d]thiazole unit into the molecular structure resulted in a high incident photon-to-current conversion efficiency (more than 70%) from 340 nm to 600 nm. One solar cell containing a benzo[d]thiazole unit, produced a η of 5.85% (JSC = 10.63 mA cm−2, VOC = 0.72 V, and ff = 0.77) under 100 mW cm−2 simulated AM 1.5 G solar irradiation.

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► Three organic dyes with different π-conjugated bridges were applied in dye-sensitized solar cells.
► The benzo[d]thiazole unit was introduced into D–π–A organic sensitizer to inhibit aggregation.
► The device based on sensitizer DBT1 achieved an efficiency of 5.85% was measured for a solar cell device.