Visualizing the valence states of europium ions in Eu-doped BaAl₂O₄ using X-ray nanoprobe mapping

Abstract

This study develops and successfully demonstrates visualization methods for the characterization of europium (Eu)-doped BaAl2O4 phosphors using X-ray nanoprobe techniques. X-ray fluorescence (XRF) mapping not only gives information on the elemental distributions but also clearly reveals the valence state distributions of the Eu2+ and Eu3+ ions. The accuracy of the estimated valence state distributions was examined by performing X-ray absorption spectroscopy (XAS) across the Eu L 3-edge (6.977 keV). The X-ray excited optical luminescence (XEOL) spectra exhibit different emission lines in the selected local areas. Their corresponding emission distributions can be obtained via XEOL mapping. The emission properties can be understood through correlation analysis. The results demonstrate that the main contribution to the luminescence intensity of the Eu-doped BaAl2O4 comes from the Eu2+ activator and the emission intensity will not be influenced by the concentration of Eu2+ or Eu3+ ions. It is anticipated that X-ray nanoprobes will open new avenues with significant characterization ability for unravelling the emission mechanisms of phosphor materials.

Shielding effect and compensation defect study on Na3Sc2(PO4)y:Eu2+,3+ (y = 2.6–3.0) phosphor by anion-group-induced phase transition

“…Therefore, using the XRF mapping, the induced shielding effect on Eu 2+ (6975 eV) and Eu 3+ (6983 eV) ions by the anion group of P ions (2146 eV) can be measured. 27 The y = 2.6 distributions of Eu 2+ (6975 eV), Eu 3+ (6983 eV), and P (2146 eV) are shown in Fig. 4a, b, and c, respectively.…”

Cation Substitution-Induced Partial Inversion to Pervade Short-Wave Infrared Light for Improving the Accuracy of Artificial Intelligence Image Recognition System

“…XANES is a powerful technology for charge variation research involving synchrotron radiation. 29 The K-edge transition of Ni from the 1s core electron to the 4p electron in the conduction band as well as the Ni 2+ peak of the XANES spectrum at approximately 8350 eV are presented in Figure 2. 30 At y = 0 to 0.9, the energy from 8352 eV shifts to 8350 eV, which indicates that Ni valence decreases from Ni 2+/3+ to Ni 2+ .…”