A high-efficiency cyanine dye for dye-sensitized solar cells

A novel organic cyanine dye containing triphenylamine-benzothiadiazole dyad has been synthesized and applied successfully to sensitization of nanocrystalline TiO₂-based solar cell. Their absorption spectra, electrochemical, and photovoltaic properties were studied. Upon adsorption on a TiO₂ electrode, the absorption spectra of the cyanine dye are all broadened at both the red and blue spectral ends relative to its respective spectra in acetonitrile and ethanol mixture solution. An overall conversion efficiency of 7.62% (J_sc=22.10 mA cm⁻², V_oc=0.54 V, ff=0.48) is achieved under irradiation with 75 mW cm⁻² white light from a Xe lamp.