Effect of molecular weight of oligomer on ionic diffusion in oligomer electrolytes and its implication for dye-sensitized solar cells

Jong Hyuk Park, Kyu Jin Choi, Junkyung Kim, Yong Soo Kang, Sang Soo Lee

Research output: Contribution to journalArticle

15 Citations (Scopus)


This study measures the diffusion coefficients of I- and I3 - in oligomer electrolytes as a function of the molecular weight of oligomers and investigates their effect on the performance of dye-sensitized solar cells (DSSCs). The high-diffusion coefficients of ions in an oligomer electrolyte with a lower molecular weight can help to promote the redox mechanism in DSSCs and thereby increase the short-circuit current density. They can also cause a decrease in the open-circuit voltage since a high-diffusion coefficient of I3 - is capable of reducing the lifetime of electrons in TiO2 electrodes. To offset these effects, N-methyl-benzimidazole is added to the oligomer electrolytes, thereby improving the open-circuit voltage and fill factor and, consequently, the overall energy-conversion efficiency, which increases to over 5%. A further test involving storage at a high temperature of 75 °C demonstrates that DSSCs employing the oligomer electrolytes show excellent thermal stability over 200 h.

Original languageEnglish
Pages (from-to)1029-1033
Number of pages5
JournalJournal of Power Sources
Issue number2 SPEC. ISS.
Publication statusPublished - 2007 Nov 15



  • Dye-sensitized solar cell
  • Ionic diffusion
  • Molecular weight
  • Non-volatile electrolyte
  • Poly(ethylene glycol)

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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