Four novel D–D–π–A configuration metal-free organic dyes (C3, P2, C2 and P3) with triphenylethylene phenothiazine moieties or triphenylethylene carbazole moieties as additional electron donors for dye-sensitized solar cells (DSSCs) have been synthesized. The cells based on C3, P2, C2 and P3 dyes with efficiencies of 2.14%, 2.69%, 5.51% and 6.55%, respectively, are obtained. The P3 based cell exhibits the highest efficiency of 6.55 ...