Mechanism of X-ray excited optical luminescence (XEOL) in europium doped BaAl2O4 phosphor

Abstract

This paper reports a luminescence mechanism in Eu-doped BaAl₂O₄ excited with monochromatic X-rays (also known as X-ray excited optical luminescence – XEOL) from synchrotron radiation. The material was prepared via a proteic sol–gel methodology. The X-ray absorption near edge structures (XANES) at the Ba L_III- and Eu L_III-edges exhibit typical absorption spectra. XEOL spectra recorded in energy ranges, either around the Ba L_III- or Eu L_III-edges, showed important differences concerning the intensity of the Eu²⁺ or Eu³⁺ emission bands. Nevertheless, the total area under the XEOL spectra increases as the energy of the X-ray photons increases in both ranges (Ba L_III- and Eu L_III-edges).