Abstract
Nanoporous, p-type NiO films were sensitized with coumarin 343 (C343), and the photoinduced electron transfer dynamics was studied in the presence of different concentrations of electrolyte (I3-/I- in propylene carbonate). Electron transfer from the valence band of NiO to the excited C343 is very fast, occurring on time scales from hundreds of femtoseconds to a few picoseconds, but also the subsequent recombination is quite rapid, on the time scale of tens of picoseconds. Nevertheless, formation of an intermediate, attributed to I2 -I NiO(+), was observed on the picosecond time scale. Simultaneously the reduced dye was converted back to the C343 ground state, indicating that recombination could be intercepted by I3 - reduction. Consistent with that interpretation, we observed oxidized NiO and depletion of I3 - persisting on the millisecond time scale. Complete dye-sensitized solar cells (DSSCs) with these films as photocathode gave up to 10-11% incident photon to current conversion efficiency at the C343 visible absorption maximum, which is the highest value reported for a p-type DSSC. Our results elucidate the main mechanism for photocurrent generation in this p-type DSSC, which is important for the understanding and development of these rarely studied counterpart of conventional n-type "Grätzel cells".
| Original language | English |
|---|---|
| Pages (from-to) | 9530-9537 |
| Number of pages | 8 |
| Journal | Journal of Physical Chemistry C |
| Volume | 112 |
| Issue number | 25 |
| DOIs | |
| Publication status | Published - Jun 26 2008 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Energy(all)
Cite this
Coumarin 343-NiO films as nanostructured photocathodes in dye-sensitized solar cells : Ultrafast electron transfer, effect of the i3/I - redox couple and mechanism of photocurrent generation. / Morandeira, Ana; Boschloo, Gerrit; Hagfeldt, Anders; Hammarström, Leif.
In: Journal of Physical Chemistry C, Vol. 112, No. 25, 26.06.2008, p. 9530-9537.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Coumarin 343-NiO films as nanostructured photocathodes in dye-sensitized solar cells
T2 - Ultrafast electron transfer, effect of the i3/I - redox couple and mechanism of photocurrent generation
AU - Morandeira, Ana
AU - Boschloo, Gerrit
AU - Hagfeldt, Anders
AU - Hammarström, Leif
PY - 2008/6/26
Y1 - 2008/6/26
N2 - Nanoporous, p-type NiO films were sensitized with coumarin 343 (C343), and the photoinduced electron transfer dynamics was studied in the presence of different concentrations of electrolyte (I3-/I- in propylene carbonate). Electron transfer from the valence band of NiO to the excited C343 is very fast, occurring on time scales from hundreds of femtoseconds to a few picoseconds, but also the subsequent recombination is quite rapid, on the time scale of tens of picoseconds. Nevertheless, formation of an intermediate, attributed to I2 -I NiO(+), was observed on the picosecond time scale. Simultaneously the reduced dye was converted back to the C343 ground state, indicating that recombination could be intercepted by I3 - reduction. Consistent with that interpretation, we observed oxidized NiO and depletion of I3 - persisting on the millisecond time scale. Complete dye-sensitized solar cells (DSSCs) with these films as photocathode gave up to 10-11% incident photon to current conversion efficiency at the C343 visible absorption maximum, which is the highest value reported for a p-type DSSC. Our results elucidate the main mechanism for photocurrent generation in this p-type DSSC, which is important for the understanding and development of these rarely studied counterpart of conventional n-type "Grätzel cells".
AB - Nanoporous, p-type NiO films were sensitized with coumarin 343 (C343), and the photoinduced electron transfer dynamics was studied in the presence of different concentrations of electrolyte (I3-/I- in propylene carbonate). Electron transfer from the valence band of NiO to the excited C343 is very fast, occurring on time scales from hundreds of femtoseconds to a few picoseconds, but also the subsequent recombination is quite rapid, on the time scale of tens of picoseconds. Nevertheless, formation of an intermediate, attributed to I2 -I NiO(+), was observed on the picosecond time scale. Simultaneously the reduced dye was converted back to the C343 ground state, indicating that recombination could be intercepted by I3 - reduction. Consistent with that interpretation, we observed oxidized NiO and depletion of I3 - persisting on the millisecond time scale. Complete dye-sensitized solar cells (DSSCs) with these films as photocathode gave up to 10-11% incident photon to current conversion efficiency at the C343 visible absorption maximum, which is the highest value reported for a p-type DSSC. Our results elucidate the main mechanism for photocurrent generation in this p-type DSSC, which is important for the understanding and development of these rarely studied counterpart of conventional n-type "Grätzel cells".
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U2 - 10.1021/jp800760q
DO - 10.1021/jp800760q
M3 - Article
VL - 112
SP - 9530
EP - 9537
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 25
ER -