Triphenylamine-based organic dyes containing a 1,2,3-triazole bridge for dye-sensitized solar cells via a 'Click' reaction

Three new organic dyes with one, two and three branched D-pi-A A structures derived from an electron donating triphenylamine core and connected by 1,2,3-triazole group to an electron deficient cyanoacrylate system have been conveniently synthesized via a 'Click' reaction. It was found that all three dyes show UV-vis absorptions in the 300-500 nm range with high molar extinction coefficients. A red-shift of UV-vis absorption band was observed in the solid thin film compared with the dioxane solution. Dye-sensitized solar cell devices based on the dyes were fabricated and tested. The one branched triphenylamine-based dye exhibits the highest energy conversion efficiency. Increase of the branched D-pi-A structure around the triphenylamine core results in the decrease of energy conversion efficiency of the dyes, which can be attributed to less attachment of the dyes onto TiO2 photoanode with the enlarged molecular size of the corresponding multibranched structure. (C) 2011 Elsevier Ltd. All rights reserved.