Positional isomers of pyridine linked triphenylamine-based donor-acceptor organic dyes for efficient dye-sensitized solar cells

•Synthesized meta and ortho positional isomers of pyridine linked triphenylamine D-A organic dyes D1 and D2.•Optical and electrochemical properties were investigated.•These dyes were used as sensitizers for dye sensitized solar cells.•The PCE of DSSC based on D1 and D2 are 5.16% and 4.27% respectively.

Two donor-acceptor (D-A) metal free dyes 3-{4-[Bis-(4-pyridin-2-ylethynyl-phenyl)-amino]-phenyl}-2-cyano-acrylic acid (D1) and 3-{4-[Bis-(4-pyridin-3-ylethynyl-phenyl)-amino]-phenyl}-2-cyano-acrylic acid (D2) have been designed, synthesized and used as sensitizers for the dye sensitized solar cells (DSSCs). The DSSCs based on D1 and D2 exhibit the power conversion efficiency (PCE) of 5.16% and 4.27%, respectively. The higher PCE value of D1 based DSSC is attributed to its enhanced short circuit current (Jsc) and open-circuit voltage (Voc) and fill factor (FF) values. The electrochemical impedance spectra demonstrated shorter electron transport time, longer electron lifetime and high charge recombination resistance for DSSC based on D1, as well as larger dye loading onto TiO2 are attributed to the higher PCE.

Graphical abstractDye sensitized solar cells based on D1 and D2 yielded Power conversion efficiency 5.61% and 4.27%, respectively.Figure optionsDownload full-size imageDownload as PowerPoint slide