Organic dyes with oligo-n-hexylthiophene for dye-sensitized solar cells: Relation between chemical structure of donor and photovoltaic performance

Organic dyes with the oligohexylthiophene linkage having several donor parts, carbazole, indole, and indoline, were newly synthesized as sensitizers for dye-sensitized solar cells. The carbazole was most efficient donor moiety for DSSCs among these dyes with the oligothiophene linkage. Carbazole dyes were adsorbed with larger amount of molecules on the TiO2 film than both indole dyes and indoline dyes. Therefore, both the VOC and the electron lifetime of DSSCs with the carbazole dyes were highly observed. The decreasing of JSC of DSSCs with indole and indoline dyes also caused by the reducing the adsorption amount of dyes.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We synthesized nine new dyes with the oligohexylthiophene linkage. ► We investigated the relation between donor structures and photovoltaic performances. ► The absorption property of indoline dyes was improved due to high donor ability. ► The performances of DSSCs/indoline were worse than those for the carbazole dyes. ► The dye-uptake on the TiO2 electrode strongly affected the performances of DSSCs.