Degradation mechanisms in organic solar cells: Localized moisture encroachment and cathode reaction

Xizu Wang, Cindy Xinxin Zhao, Gu Xu*, Zhi Kuan Chen, Fu Rong ZHU

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

90 Citations (Scopus)


Organic solar cells (OSCs) have been under intensive studies, due to their attractive properties such as large scale, low cost, lightweight. However, their short lifetime, compared with the inorganic counterparts, has placed a severe restriction on the potential applications. To reveal the cause of the short life, here we report the finding of two distinguishable degradation mechanisms, from a typical organic/polymeric solar cell, based on polymer blend of regioregular poly(3-hexylthiophene):[6,6]-phenyl-C61-butyric acid methyl ester, fabricated on indium tin oxide-coated glass substrate. The first mode is associated with a localized failed area due to moisture encroachment, where the confronted areas are either completely dead or still 100% functioning. The second mode was found to be related to a mild decrease in power conversion efficiency (PCE) and was induced by a possible interfacial passivation occurred at the organic/cathode interface, due to the presence of residual oxygen, moisture and other impurities. The simulation results agree well with our experimental findings in showing that the degradation due to the localized moisture encroachment may be delayed by encapsulating the OSCs with desiccant. The degradation due to the interfacial passivation could be eliminated by the removal of low work function cathode at the sacrifice of PCE.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalSolar Energy Materials and Solar Cells
Publication statusPublished - Sept 2012

Scopus Subject Areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films

User-Defined Keywords

  • Degradation
  • Lifetime
  • Organic photovoltaics
  • Solar cells


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