Nonomura, KazuteruVlachopoulos, NickUnger, EvaHaggman, LeifHagfeldt, AndersBoschloo, Gerrit2019-06-182019-06-182019-06-182019-05-0210.1149/2.0281909jeshttps://infoscience.epfl.ch/handle/20.500.14299/157771WOS:000466839800002The addition of a compact titanium dioxide (TiO2) layer between the fluorine-doped tin oxide (FTO) coated glass substrate and the mesoporous TiO2 layer in the dye-sensitized solar cell (DSC) based on the iodide/triiodide redox couple (I-/I-3(-)) is known to improve its current-voltage characteristics. The compact layer decreases the recombination of electrons extracted through the FTO layer with I-3(-) around the maximum power point. Furthermore, the short-circuit photocurrent was improved, which previously has been attributed to the improved light transmittance and/or better contact between TiO2 and FTO. Here, we demonstrate that the compact TiO2 layer has another beneficial effect: it blocks the reaction between charge carriers in the FTO and photogenerated diiodide radical species (I-2(-center dot)). Using photomodulated voltammetry, it is demonstrated that the cathodic photocurrent found at bare FTO electrodes is blocked by the addition of a compact TiO2 layer, while the anodic photocurrent due to reaction with I-2(-center dot) is maintained. (C)The Author(s) 2019. Published by ECS.ElectrochemistryMaterials Science, Coatings & FilmsElectrochemistryMaterials Scienceconducting glass/tio2 interfacestitanium-dioxideredox coupleelectron-transferback-reactionlow-costefficientfilmsdepositioncomplexestext::journal::journal article::research article