Blocking the Charge Recombination with Diiodide Radicals by TiO2 Compact Layer in Dye-Sensitized Solar Cells

The 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.


Published in:
Journal Of The Electrochemical Society, 166, 9, B3203-B3208
Year:
May 02 2019
Publisher:
Pennington, ELECTROCHEMICAL SOC INC
ISSN:
0013-4651
1945-7111
Keywords:
Laboratories:




 Record created 2019-06-18, last modified 2019-06-25


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