Blocking the charge recombination with diiodide radicals by TiO2 compact layer in dye-sensitized solar cells

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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/I3) is known to improve its current-voltage characteristics. The compact layer decreases the recombination of electrons extracted through the FTO layer with I3 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 (I2−•). 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 I2−• is maintained.


  • Kazuteru Nonomura
  • Nick Vlachopoulos
  • Eva Unger
  • Leif Häggman
  • Anders Hagfeldt
  • Gerrit Boschloo
Enheter & grupper
Externa organisationer
  • Swiss Federal Institute of Technology
  • Helmholtz-Zentrum Berlin for Materials and Energy
  • Uppsala universitet

Ämnesklassifikation (UKÄ) – OBLIGATORISK

  • Materialkemi
Sidor (från-till)B3203-B3208
TidskriftJournal of the Electrochemical Society
Utgåva nummer9
StatusPublished - 2019
Peer review utfördJa