Multi-carbazole derivatives: new dyes for highly efficient dye-sensitized solar cells

Three new multi-carbazole derivatives (2C–4C) with a twisted and zigzag-shape structure were designed, synthesized and used as sensitizers for dye-sensitized solar cells (DSSCs). The results showed that this non-planar structure of 2C–4C, combined with multi alkyl chains, can efficiently inhibit dye aggregation and charge recombination, which gave DSSCs with a high open circuit voltage (Voc) and an overall solar-to-electric conversion efficiency (η) of up to 6.33%.