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Dye regeneration and charge recombination in dye-sensitized solar cells with ferrocene derivatives as redox mediators

Journal Article


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Abstract


  • Ferrocene compounds are promising redox shuttles for application in dye-sensitized solar cells (DSCs). Chemical modification of the cyclopentadienyl rings is easily achievable affording almost unlimited variation of the redox properties. This allows fine-tuning of the driving force for dye-regeneration and optimization of the energy conversion efficiency of DSCs. Herein, six ferrocene derivatives have been chosen for investigation which cover the large redox potential range of 0.85 V, by virtue of simple alkylation and halogenation of the cyclopentadienyl ring, and enable improved matching of the energy levels of the sensitizer and the electrolyte. Although the focus of this work was to examine the effect of the redox potential on charge transfer processes, DSCs were fabricated which achieved high energy conversion efficiencies of over 5%. Charge transfer reactions were studied to reveal the dependence of the dye regeneration rate, recombination losses and recombination pathways on the reaction driving force. An increase in redox potential led to a higher efficiency due to higher open circuit potentials until a threshold is reached. At this threshold, the driving force for dye regeneration (18 kJ mol -1, ΔE = 0.19 V) becomes too small for efficient device operation, leading to rapid recombination between the oxidized dye and electrons in the TiO 2 conduction band. As a result of this work guidelines can be formulated to aid the selection of redox couples for a particular sensitizer in order to maximize the utilization of incident solar energy. © 2012 The Royal Society of Chemistry.

UOW Authors


  •   Daeneke, A (external author)
  •   Mozer, Attila
  •   Kwon, Tae-Hyuk (external author)
  •   Duffy, Noel W. (external author)
  •   Holmes, A B. (external author)
  •   Bach, Udo (external author)
  •   Spiccia, Leone (external author)

Publication Date


  • 2012

Citation


  • Daeneke, T., Mozer, A. J., Kwon, T., Duffy, N. W., Holmes, A., Bach, U. & Spiccia, L. (2012). Dye regeneration and charge recombination in dye-sensitized solar cells with ferrocene derivatives as redox mediators. Energy and Environmental Science, 5 (5), 7090-7099.

Scopus Eid


  • 2-s2.0-84860385736

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=7605&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/4263

Number Of Pages


  • 9

Start Page


  • 7090

End Page


  • 7099

Volume


  • 5

Issue


  • 5

Place Of Publication


  • http://www.rsc.org/Publishing/Journals/EE/Index.asp

Abstract


  • Ferrocene compounds are promising redox shuttles for application in dye-sensitized solar cells (DSCs). Chemical modification of the cyclopentadienyl rings is easily achievable affording almost unlimited variation of the redox properties. This allows fine-tuning of the driving force for dye-regeneration and optimization of the energy conversion efficiency of DSCs. Herein, six ferrocene derivatives have been chosen for investigation which cover the large redox potential range of 0.85 V, by virtue of simple alkylation and halogenation of the cyclopentadienyl ring, and enable improved matching of the energy levels of the sensitizer and the electrolyte. Although the focus of this work was to examine the effect of the redox potential on charge transfer processes, DSCs were fabricated which achieved high energy conversion efficiencies of over 5%. Charge transfer reactions were studied to reveal the dependence of the dye regeneration rate, recombination losses and recombination pathways on the reaction driving force. An increase in redox potential led to a higher efficiency due to higher open circuit potentials until a threshold is reached. At this threshold, the driving force for dye regeneration (18 kJ mol -1, ΔE = 0.19 V) becomes too small for efficient device operation, leading to rapid recombination between the oxidized dye and electrons in the TiO 2 conduction band. As a result of this work guidelines can be formulated to aid the selection of redox couples for a particular sensitizer in order to maximize the utilization of incident solar energy. © 2012 The Royal Society of Chemistry.

UOW Authors


  •   Daeneke, A (external author)
  •   Mozer, Attila
  •   Kwon, Tae-Hyuk (external author)
  •   Duffy, Noel W. (external author)
  •   Holmes, A B. (external author)
  •   Bach, Udo (external author)
  •   Spiccia, Leone (external author)

Publication Date


  • 2012

Citation


  • Daeneke, T., Mozer, A. J., Kwon, T., Duffy, N. W., Holmes, A., Bach, U. & Spiccia, L. (2012). Dye regeneration and charge recombination in dye-sensitized solar cells with ferrocene derivatives as redox mediators. Energy and Environmental Science, 5 (5), 7090-7099.

Scopus Eid


  • 2-s2.0-84860385736

Ro Full-text Url


  • http://ro.uow.edu.au/cgi/viewcontent.cgi?article=7605&context=scipapers

Ro Metadata Url


  • http://ro.uow.edu.au/scipapers/4263

Number Of Pages


  • 9

Start Page


  • 7090

End Page


  • 7099

Volume


  • 5

Issue


  • 5

Place Of Publication


  • http://www.rsc.org/Publishing/Journals/EE/Index.asp