Electron-Density and Electron-Lifetime Profile in Nanocrystalline-TiO2 Electrode of Dye-Sensitized Solar Cells Analysed by Voltage Decay and Charge Extraction

The dependence of the electron density and electron lifetime in nanocrystalline-TiO2 electrode on the electron back reaction with I3− in a dye-sensitized solar cell, based on a mesoporous titania (TiO2) matrix immersed in an iodine-based electrolyte, has been presented by analyzing the results of voltage decay and charge extraction measurements without modelling, without interpretation of mechanism, and without complicating calculations. This new analysis approach utilizes simple equations and basic definition of kinetics, concluding in absolute electron-density and charge-lifetime measurements. The relation of electron lifetime to open-circuit voltage indicates a peak of the long-lifetime charge at 5.5 V, which is consistent with the information of middle band suggested by Bisquert et al. (2004).