Large Polaron Conduction, Photoconductivity, and Photochromism in GdOxH3−2x Oxyhydride Thin Films

Giorgio Colombi*, Bart Boshuizen, Diana Chaykina, Leyi Hsu, Herman Schreuders, Tom J. Savenije, Bernard Dam

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

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At ambient conditions, rare-earth oxyhydride thin films show reversible photochromism and photoconductivity, while their mechanism and relation are still unclear. In this work, this question is explored with in situ time-resolved measurements of both optical and transport properties of Gd-based oxyhydride thin films. It is found that p-type large polaron conduction is the initial mechanism of charge transport; however, upon photo-darkening, a 104-fold increase of conductivity occurs, and n-type carriers become dominant. Further, photochromism and photoconductivity are shown to originate from a single process, as indicated by the fact that the photoconductivity is exponentially proportional to the increase of optical absorption. This exponential relation, notably, cannot stem from any of the optically absorbing species thought responsible for photochromism and, therefore, suggests that their formation is accompanied by a concerted increase of negative charge carriers in the Gd oxyhydride films.

Original languageEnglish
Article number2202660
Number of pages10
JournalAdvanced Optical Materials
Issue number15
Publication statusAccepted/In press - 2023


  • gadolinium
  • hydrides
  • oxyhydrides
  • photochromism
  • photoconductivity
  • polarons

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