Impact of blocking layer on DSSC performance based on new dye -indolo[3,2,1-jk]carbazole derivative and N719

Abstract

The impact of the thickness of the TiO2 blocking layer (50, 150 and 300 nm) on DSSC performance based on a new D-D-π-A architecture of metal-free organic dyes and commercial N719 was investigated. The blocking layers were prepared by atomic layer deposition. New indolo[3,2,1-jk]carbazole derivatives as sensitizers with a phenothiazine unit and an acetylene linkage containing either an aldehyde or cyanoacrylic acid were designed, synthesized and characterized. However, the lack of anchoring ability of –CHO group with TiO2 was demonstrated. It was found that the blocking layer thickness has an important role in cell performance. Finally, by the optimum thickness of TiO2 film being 50 nm, the highest efficiency was achieved at 3.70, 8.49 and 8.05% for DSSC based on indolo[3,2,1-jk]carbazole derivative, N719 and mixture of these dyes.