Engineering of the electron donor of triarylamine sensitizers for high-performance dye-sensitized solar cells

Triphenylamine (TPA) and their derivatives are well-known electron-rich compounds that are widely used in various optical and electronic fields. Here, two new organic dyes (M40 and M41) featuring TPA or dihexyloxy-substituted triphenylamine (DHO-TPA) electron donor have been designed and synthesized. M40 sensitized DSCs employing the Co(II/III)-tris(1,10-phenanthroline)-based redox electrolyte affords a short circuit photocurrent of 14.32 mA cm(-2), an open circuit voltage of 907 mV, and a fill factor of 0.68, corresponding to an overall conversion efficiency of 8.83% under standard AM 1.5 sunlight. This efficiency is much higher than those of the M41 sensitized DSCs, being 7.81% under the same conditions. Absorption spectra, electrochemical measurements, theoretical calculations, and photovoltaic measurements are used to compare the light absorptions, energy-levels, and charge transfer dynamics that contribute to the photovoltaic behavior. (C) 2014 Elsevier B.V. All rights reserved.