Characterization of two new (A–π)2–D–A type dyes with different central D unit and their application for dye sensitized solar cells

• Two dyes different TPA (D1) and pyran (D2) donor central unit used as sensitizer.
• The overall PCE is about 5.16% and 4.42% for DSSCs with D1 and D2, respectively.
• Longer electron lifetime for DSSC sensitized with D1 results higher PCE.
• Smaller charge transport resistance for D1 sensitized DSSC.

We report the photophysical, electrochemical and theoretical properties of two dyes with same acceptor, π-linker and anchoring acceptor unit and different TPA (D1) and pyran (D2) donor central unit. The change in the central unit resulted in corresponding different photophysical and electrochemical properties. The dye sensitized solar cell fabricated using dye D1 showed the higher incident photon to current efficiency of 54%, a short circuit current (Jsc) of 11.86 mA/cm2, an open circuit voltage of 0.64 V, and fill factor (FF) of 0.68, corresponding an overall power conversion efficiency of 5.16% which is higher than that for D2 based DSSCs (4.42%). The difference in the PCE of DSSCs based on D1 and D2 is partly, due to the smaller amount of dye loading, higher dark current and charge recombination rate of D1 based DSSC. The electrochemical spectra of DSSCs demonstrated longer electron life time and charge recombination resistance and small charge transport resistance for D1 sensitized DSSC, results the higher PCE.

The over all PCE for DSSC sensitized with D1 and D2 is 5.16% and 4.42%, respectively.Figure optionsDownload as PowerPoint slide