Structural, morphological and scintillation properties of Ce 3+-doped Y 3Al 5O 12 powders and films elaborated by the sol–gel process

Abstract

Luminescent Ce 3+-doped and Ce 3+/Tb 3+-codoped Y 3Al 5O 12 powders and spray-coated films have been elaborated by the sol–gel technique. Their purity has been assessed by X-ray diffraction whereas X-ray Absorption Spectroscopy has evidenced the partial oxidation of Ce 3+ into Ce 4+ in samples containing or not Tb 3+. Film thicknesses have been determined by profilometry. Powder and film morphology has been studied using Scanning Electron and Transmission Electron Microscopies, evidencing nanostructured well-densified phosphors. Scintillation properties of both kinds of samples have been investigated upon X-ray radiation and optimal cerium concentration has been determined for crystallized powders. Substitution of one part of yttrium ions by terbium ions in Y 3Al 5O 12:Ce samples has entailed a significant enhancement of scintillation efficiency for both powders and films. These improvements will be discussed regarding in particular the changes in the X-ray absorption by photoelectric effect related to the matrix modification. In addition to this enhancement, emission maximum of co-doped samples is red-shifted to 544 nm, that matches more suitably with the optical photon detectors used in X-ray imaging.