Design of organic dyes for dye-sensitized solar cells: Extending π-conjugation backbone via ‘Click’ reaction to improve photovoltaic performances

•Dyes containing 1,2,3-triazole unit has been synthesized via the “Click” reaction.•The thienyl group as a π-bridge can improve the short-circuit current of the DSSCs.•The relationship of structure with photovoltaic property was primarily explored.

The organic dyes have been synthesized via a ‘Click’ reaction and employed in dye-sensitized solar cells, in which an electron-deficient 1,2,3-triazole unit is introduced to connect the thienyl group and the phenoxyl group as π-linkers. Compared with the non-thiophene containing reference dye, these new dyes show stronger intramolecular charge transfer and higher molar extinction coefficient with incremental increase of thienyl groups. Thus, the short-circuit current of solar cells based on them is greatly increased. Moreover, the existence of 1,2,3-triazole unit is favorable for the charge separation that can retard the charge recombination and improve the open circuit voltage. Consequently, the solar cell based on the dithienyl containing dye presents the best performance with a Jsc of 10.00 mA cm−2, a Voc of 0.68 V and a FF of 0.71, corresponding to an overall conversion efficiency of 4.81% among them.

Graphical abstractThe dyes containing an electron-deficient 1,2,3-triazole unit has been synthesized for DSSCs. The introduction of thienyl groups extends the conjugation length and strengthens the intramolecular charge transfer, and the existence of 1,2,3-triazole group is beneficial for the spatial separation of charge.Figure optionsDownload full-size imageDownload as PowerPoint slide