An unusual thiazolo[5,4-d]thiazole sensitizer for dye-sensitized solar cells

A novel unsymmetrical thiazolo[5,4-d]thiazole, TZ1, endowed with an unusual π–D–A structure featuring a highly conjugated light-harvesting backbone, has been synthesized and characterized from the photo- and electrochemical point of view. Although its structure did not resemble that of typical organic sensitizers, the new compound showed properties compatible with its employment in dye-sensitized solar cells. The experimental findings were supported by the results of DFT calculations. Indeed, when tested as a sensitizer in dye-sensitized solar cells, compound TZ1 gave rise to a high average open-circuit voltage (Voc) of 0.712 V and an average short-circuit current (Jsc) of 7.0 mA cm−2, resulting in a power conversion efficiency (η) of 2.55%.