Abstract
We have systematically tuned the spectral response of black dye using the co-sensitization technique. In this study we have selected two co-sensitizers coded as AK-01 and U01. The individual overall conversion efficiencies (eta) of these co-sensitizers AK-01 and U01 are 6.20% and 6.01%, respectively. A better power conversion efficiency of 10.21% and 10.56% of DSSC was observed when black dye was co-sensitized with AK-01 and U01, respectively, compare to individual single black dye (9.18%). Both AK-01 and U01 co-sensitizers effectively overcome the light absorption of redox electrolyte and improved the dip in the incident-photon-to-current conversion efficiency spectra at 350-420 nm region compared with single black dye. Intensity-modulated photovoltage spectroscopy result shows the longer lifetime of black dye+U01 compared to the black dye which suggest the robust U01 dye sufficiently suppressed the recombination of electrons in the TiO2 with redox electrolyte without any interaction with black dye when co-adsorbed on TiO2. (C) 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim