Iodide-Free Ionic Liquid with Dual Redox Couples for Dye-Sensitized Solar Cells with High Open-Circuit Voltage

Chun Ting Li, Chuan Pei Lee, Chi Ta Lee, Sie Rong Li, Shih Sheng Sun*, Kuo Chuan Ho

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)


A novel ionic-liquid mediator, 1-butyl-3-{2-oxo-2-[(2,2,6,6-tetramethylpiperidin-4-yl)amino]ethyl}-1H-imidazol-3-ium selenocyanate (ITSeCN), has been successfully synthesized for dye-sensitized solar cells (DSSCs). ITSeCN possesses dual redox channels, imidazolium-functionalized 2,2,6,6-tetramethylpiperidine N-oxyl (TEMPO) and selenocyanate, which can serve as the cationic redox mediator and the anionic redox mediator, respectively. Therefore, ITSeCN has a favorable redox nature, which results in a more positive standard potential, larger diffusivity, and better kinetic heterogeneous rate constant than those of iodide. The DSSC with the ITSeCN electrolyte shows an efficiency of 8.38% with a high open-current voltage (VOC) of 854.3 mV, and this VOC value is about 150 mV higher than that for the iodide-based DSSC. Moreover, different electrocatalytic materials were employed to trigger the redox reaction of ITSeCN. The ITSeCN-based DSSC with the CoSe counter electrode achieved the best performance of 9.01%, which suggested that transition-metal compound-type materials would be suitable for our newly synthesized ITSeCN mediator.

Original languageEnglish
Pages (from-to)1244-1253
Number of pages10
Issue number7
Publication statusPublished - 2015 Apr 13
Externally publishedYes


  • dye-sensitized solar cells
  • electrochemistry
  • ionic liquids
  • radicals
  • redox chemistry

ASJC Scopus subject areas

  • Environmental Chemistry
  • General Chemical Engineering
  • General Materials Science
  • General Energy


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