Enhanced performance of dye-sensitized solar cells with novel 2,6-diphenyl-4H-pyranylidene dyes

Novel 2,6-diphenyl-4H-pyranylidene derivatives were designed and synthesized as dyes for dye-sensitized solar cells (DSSC). Dyes 2a, b with a phenyl substituent showed high DSSC energy conversion efficiencies of 5.3% (Jsc = 10.3 mA/cm2, Voc = 0.72 V, FF = 0.72) and 4.7% (Jsc = 8.9 mA/cm2, Voc = 0.73 V, FF = 0.72) at 100 mW/cm2 under simulated AM 1.5 G solar light conditions. These values are twice better than that of dye 1 without the phenyl substituent under the same conditions. Both the photocurrent density (Jsc) and open circuit voltage (Voc) of DSSCs based on dyes 2a, b are increased compared with 1. It can be attributed to their twisted structures, absorption abilities and proper energy levels. This result shows that the tetraphenylpyranylidene is a promising electron-donor unit for high-efficiency DSSCs.

Graphical abstractNovel organic dyes with 2,6-diphenyl-4H-pyranylidene unit as donor part were developed for dye-sensitized solar cells and phenyl-substituted derivatives 2a, b showed good energy conversion efficiencies of 5.3 and 4.7%.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We developed novel diphenylpyranylidene dyes for DSSCs application. ► The newly introduced phenyl group leads to greater steric effect. ► Phenyl-substituted dyes showed good DSSC efficiencies of 5.3% and 4.7%.