A new class of organic sensitizers with fused planar triphenylamine for nanocrystalline dye sensitized solar cells

Five novel organic sensitizers that contain a fused-planar triphenylamine as electron donor have been synthesized and their photophysical properties, theoretical calculation and photovoltaic performances as well as stability test have been studied. Under standard AM 1.5 sunlight, the sensitizer JK-164 yielded a short-circuit photocurrent density of 15.32 mA cm−2, an open-circuit voltage of 0.70 V, and a fill factor of 0.74, corresponding to an overall conversion efficiency of 7.86%. The JK-164 cell exhibits an excellent stability, revealing a slight change after 1000 h of light soaking at 60 °C using a solvent free ionic liquid. The cell shows a higher open-circuit voltage (Voc) compared to that of JK-163 due to an increased electron life time (τc) in the conduction band of TiO2.