No CrossRef data available.
Published online by Cambridge University Press: 22 August 2011
Temperature dependent, dark current-voltage characteristics (I-V-T) of dye sensitized solar cells (DSSCs) were used to study the TiO2 surface defects on photovoltaic performance. Three kinds of DSSCs were used for this study. (1) DSSC with no surface treatment, (2) DSSCs with Al2O3 and (3) HfO2 treatments. Activation energy of charge transport, obtained from the I-V-T of the three DSSCs, suggest that Al2O2 and HfO2 surface treatment on the nanoporous TiO2 effectively suppressed the electron capture by the surface states from the conduction band of TiO2 and the consecutive electron transfer to the electrolyte in which the TiO2 is permeated. The reference DSSC showed activation energy of 1.03eV while the DSSCs with Al2O3 and HfO2 surface treatment showed 1.27 and 1.31eV respectively. The higher activation energy, in case of HfO2 surface treatment, suggest that electronically active TiO2 surface states present near to the redox potential of the electrolyte was reduced and hence resulted in improved photovoltaic performance than Al2O3 treated DSSC and the reference DSSC.