A remarkable enhancement of efficiency by co-adsorption with CDCA on the bithiazole-based dye-sensitized solar cells

Three new organic dyes containing a 5,5′-bithiazole or 2,2′-bithiazole entity have been synthesized for dye-sensitized solar cell (DSSC) applications. The conversion efficiencies of DSSCs fabricated are moderate due to serious dye aggregation. Upon addition of CDCA co-adsorbents, the optimized cell efficiencies were improved by 43–86%. The best efficiency was 6.31%, which reached 86% of N719-based DSSC fabricated and measured under similar condition. The efficiency can be further improved to 6.45% by adding a near-IR absorbing dye as the co-sensitizer due to broadened IPCE spectrum.