On the mechanism leading to afterglow in Gd2O2S:Pr

Cees Ronda, Andries Meijerink

Research output: Contribution to journalArticleAcademicpeer-review


The performance of scintillator materials and phosphors for x-ray imaging is adversely affected by afterglow, giving rise to ghost images and thus compromising image quality. Here, the afterglow of the well-known computed tomography (CT) phosphor Gd2O2S:Pr is investigated with time-delayed afterglow spectroscopy. It is shown that these afterglow spectra mainly show Eu3+ emission. This points to a mechanism, during excitation across the bandgap, in which holes are captured by Pr3+ ions, resulting in Pr4+ and electrons are captured by Eu3+ ions, creating Eu2+. Afterglow is due to thermal excitation of electrons from the valence band to Pr4+ ions (detrapping of holes from Pr4+), restoring Pr3+ ions. Capture of the resulting holes in the valence band by Eu2+ ions leads to excited Eu3+ ions that generate Eu3+ emission thus causing the undesired afterglow. Time delayed Eu3+ afterglow spectra are observed already for very low Eu3+ concentrations (
Original languageEnglish
Article number100091
Pages (from-to)1-4
JournalOptical Materials: X
Publication statusPublished - Dec 2021


  • Afterglow
  • Computed tomography
  • Eu3+
  • Gd2O2S:Pr3+
  • Luminescence
  • Scintillator


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