Effect of different acceptors in di-anchoring triphenylamine dyes on the performance of dye-sensitized solar cells

• Three triphenylamine dyes with different dual-channel anchoring groups are applied in dye-sensitized solar cells.
• The light absorption capacity of TPACR2 is better than that for TPAC1 and TPAR2.
• Photovoltaic performance of TPACR2-based DSSC is dramatically enhanced compared with TPAC1 and TPAR2.

Three di-anchoring triphenylamine dyes, which were coded as TPAC1, TPAR2 and TPACR2, were designed and synthesized for dye-sensitized solar cell application. The structural modification effect of different anchoring groups on photophysical, electrochemical and photovoltaic properties of the related DSSCs was extensively investigated. With the variation from cyanoacetic acid via rhodanine-3-acetic acid to co-rhodanine units, the molar extinction coefficients of the maximum absorption wavelength for the three dyes gradually increase due to the extension of π system. In comparison with that for TPAC1 and TPAR2, DSSC based on dye TPACR2 with double co-rhodanine groups shows the best overall conversion efficiency of 4.64% with simultaneous enhancement of photocurrent and photovoltage, which is attributed to the higher molar extinction coefficient (6.5 × 104 M−1 cm−1), broader absorption spectra, broader IPCE spectra and longer electron lifetime.