Novel cyanine dyes with different methine chains as sensitizers for nanocrystalline solar cell

Novel cyanine dyes (Sqb and Cyb3) with carboxylbenzyl group and different methine chains as solar cell sensitizers were synthesized and the photoelectrochemical behaviors of the TiO2 nanocrystalline electrode sensitized by them were investigated. The results show that Isc (2.76 mA/cm2), monochromatic incident photon-to-current conversion efficiency (IPCE) (46%) and η (1.7%) of TiO2 nanocrystalline solar cell sensitized by Sqb were higher than that of TiO2 nanocrystalline solar cell sensitized by Cyb3 when TiO2 nanostructured porous film was 6.5 μm thick and was sensitized for 6 h and 4 h, respectively. The excited state level of these dyes matches the conductive band edge of TiO2 nanoparticles. Therefore, the sensitization of the dyes can increase the photocurrent density of TiO2 nanocrystalline electrode.