Photo-enhanced ionic conductivity across grain boundaries in polycrystalline ceramics

Thomas Defferriere, Dino Klotz, Juan Carlos Gonzalez-Rosillo, Jennifer L.M. Rupp, Harry L. Tuller

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


Grain boundary conductivity limitations are ubiquitous in material science. We show that illumination with above-bandgap light can decrease the grain boundary resistance in solid ionic conductors. Specifically, we demonstrate the increase of the grain boundary conductance of a 3 mol% Gd-doped ceria thin film by a factor of approximately 3.5 at 250 °C and the reduction of its activation energy from 1.12 to 0.68 eV under illumination, while light-induced heating and electronic conductivity could be excluded as potential sources for the observed opto-ionic effect. The presented model predicts that photo-generated electrons decrease the potential barrier heights associated with space charge zones depleted in charge carriers between adjacent grains. The discovered opto-ionic effect could pave the way for the development of new electrochemical storage and conversion technologies operating at lower temperatures and/or higher efficiencies and could be further used for fast and contactless control or diagnosis of ionic conduction in polycrystalline solids.

Original languageEnglish
JournalNature Materials
Publication statusAccepted/In press - 2022

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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