An oligothiophene dye with triphenylamine as side chains for efficient dye-sensitized solar cells

A novel oligothiophene-cyanoacrylic acid photosensitizer with two triphenylamine side chains (7T-2TPA) is designed and synthesized for dye-sensitized solar cells. 7T-2TPA exhibits broad (250–600 nm) and strong absorption (ε = 5.0 × 104 L mol−1 cm−1 at 496 nm). The optical band gap (Eg) is estimated from the onset absorption edge to be 2.07 eV. The oxidation potential Eox and reduction potential Ered vs NHE of the dye is 0.93 and −1.14 V, respectively. Dye-sensitized solar cell (DSSC) based on 7T-2TPA exhibits an open-circuit voltage (Voc) of 724 mV, a short-circuit current density (Jsc) of 16.28 mA cm−2, a fill factor (FF) of 0.684 and a power conversion efficiency of 8.06%. The efficiency of 8.06% is similar to that for widely used N719-based cell fabricated and measured under the same conditions.

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► An oligothiophene dye with two triphenylamine side chains (7T-2TPA) is synthesized.
► 7T-2TPA exhibits broad and strong absorption in the visible region.
► Dye-sensitized solar cells exhibit high power conversion efficiency of 8.06%.