Electrochemical approach to enhance the open-circuit voltage (Voc) of dye-sensitized solar cells (DSSCs)

Narayan Chandra Deb Nath, Ho Joon Lee, Won Youl Choi, Jae Joon Lee

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

The net enhancement of open-circuit voltage (Voc) of dye-sensitized solar cells (DSSCs) was achievedwith the novel electrolyte composed of interhalogen based binary-redox couples without regard to thechoice of sensitizers. The interhalogen ion, I2Br-, was formed in the conventional iodine-based elec-trolyte by both chemically and electrochemically and it was found to produce an extra redox pair, (I -,Br-)/I2Br-, with new energy state at a more positive potential than that of I-/I3 -. The Fermi level of theelectrolyte shifted positively by the weighted-average of the two redox systems. It induced the increase of V oc up to 30, 60, and 50 mV for cis-diisothiocyanato-bis(2,2′- bipyridyl-4,4′-dicarboxylato) ruthenium(II)bis(tetrabutylammonium) (N719), cis-dicyano-bis(2,2′-bipyridyl-4,4′-dicarboxylic acid) ruthenium(II)(Ruthenizer 505 or Ru505), and 2′,4′,5′,7′- tetrabromofluorescein (eosin Y) dyes, respectively, withoutaffecting the short circuit current much. It corresponded to the enhancement of the overall power con-version efficiency (η) up to 8, 14, and 13%, respectively. Moreover, the degree of enhancement of Voc was controllable by varying [I 2Br-] since the higher the contribution of [I 2Br-] the more positive shift in theenergy level of the binary redox couples.

Original languageEnglish
Pages (from-to)39-45
Number of pages7
JournalElectrochimica Acta
Volume109
DOIs
StatePublished - 2013

Keywords

  • Dye-sensitized solar cell
  • Electrolyte
  • Fermi level
  • Interhalogen
  • Redox couple

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