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

Nonomura, Kazuteru ; Vlachopoulos, Nick ; Unger, Eva LU ; Häggman, Leif ; Hagfeldt, Anders and Boschloo, Gerrit (2019) In Journal of the Electrochemical Society 166(9). p.3203-3208
Abstract

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... (More)

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.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of the Electrochemical Society
volume
166
issue
9
pages
3203 - 3208
publisher
Electrochemical Society
external identifiers
  • scopus:85066898933
ISSN
0013-4651
DOI
10.1149/2.0281909jes
language
English
LU publication?
yes
id
c66aec5f-360c-4ed3-8f7c-2371d07c64f1
date added to LUP
2019-06-25 13:26:58
date last changed
2020-09-23 07:47:40
@article{c66aec5f-360c-4ed3-8f7c-2371d07c64f1,
  abstract     = {<p>The addition of a compact titanium dioxide (TiO2) layer between the fluorine-doped tin oxide (FTO) coated glass substrate and the mesoporous TiO<sub>2</sub> layer in the dye-sensitized solar cell (DSC) based on the iodide/triiodide redox couple (I<sup>−</sup>/I<sub>3</sub><sup>−</sup>) is known to improve its current-voltage characteristics. The compact layer decreases the recombination of electrons extracted through the FTO layer with I<sub>3</sub><sup>−</sup> 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 TiO<sub>2</sub> and FTO. Here, we demonstrate that the compact TiO<sub>2</sub> layer has another beneficial effect: it blocks the reaction between charge carriers in the FTO and photogenerated diiodide radical species (I<sub>2</sub><sup>−•</sup>). Using photomodulated voltammetry, it is demonstrated that the cathodic photocurrent found at bare FTO electrodes is blocked by the addition of a compact TiO<sub>2</sub> layer, while the anodic photocurrent due to reaction with I<sub>2</sub><sup>−•</sup> is maintained.</p>},
  author       = {Nonomura, Kazuteru and Vlachopoulos, Nick and Unger, Eva and Häggman, Leif and Hagfeldt, Anders and Boschloo, Gerrit},
  issn         = {0013-4651},
  language     = {eng},
  number       = {9},
  pages        = {3203--3208},
  publisher    = {Electrochemical Society},
  series       = {Journal of the Electrochemical Society},
  title        = {Blocking the charge recombination with diiodide radicals by TiO<sub>2</sub> compact layer in dye-sensitized solar cells},
  url          = {http://dx.doi.org/10.1149/2.0281909jes},
  doi          = {10.1149/2.0281909jes},
  volume       = {166},
  year         = {2019},
}