Investigations of BaCl2:Eu2+ nanophosphor using electron paramagnetic resonance, structural analysis and thermoluminescence

Processing and Optical Properties of Eu-Doped Chloroborate Glass-Ceramic

“…Previous studies have indicated a surface crystallization in the glasses containing BaO and B 2 O 3 [24], but in the present case, the SEM image ( Figure 3) indicated a ceramization process within the glass sample volume. Eu 2+ dopants [20,21], there is a relatively small distortion of the BaCl2 crystalline structure assigned to the ionic radii difference of 1.47 Å for Ba 2+ and 1.3 Å for Eu 2+ [22]. However, for the glass-ceramic, we observed a strong crystalline lattice expansion effect (Table 1).…”

“…For Eu 2+ -doped BaCl2 nanocrystals where the Ba 2+ ions are substituted by the According to the results of the XRD pattern analysis (Table 1), the cell parameters of BaCl 2 :Eu 2+ nanocrystals in the glass ceramic showed a clear increase compared to the corresponding nanocrystalline powder. For Eu 2+ -doped BaCl 2 nanocrystals where the Ba 2+ ions are substituted by the Eu 2+ dopants [20,21], there is a relatively small distortion of the BaCl 2 crystalline structure assigned to the ionic radii difference of 1.47 Å for Ba 2+ and 1.3 Å for Eu 2+ [22]. However, for the glass-ceramic, we observed a strong crystalline lattice expansion effect (Table 1).…”

“…The same glow peaks were observed in the glass-ceramic annealed in a reducing atmosphere, where 134 °C was the dominant feature, accompanied by a shoulder at about 180 °C. The high temperature peak at 134 °C has been observed on Eu 2+ -doped BaCl2 nanocrystalline powder, and it has been assigned to the recombination of F(Cl) centers in the BaCl2 crystalline lattice [21]. During the heating, the electrons are thermally released from the F(Cl) trapping centers and recombine with holes trapped as Eu 3+ /(Eu 2+hole) centers giving rise to the excited (Eu 2+ ) * ions and radiative emission according to:…”

“…The results of the x-ray diffraction (XRD) pattern analysis of Eu-doped chloroborate glass-ceramic annealed at 570 • C in an air and reducing atmosphere (H 2 -Ar); the lattice parameters for BaCl 2[20] and BaCl 2 :Eu 2+ nanocrystals[21] are included for comparison.…”

Europium (II)-Doped CaF2 Nanocrystals in Sol-Gel Derived Glass-Ceramic: Luminescence and EPR Spectroscopy Investigations

“…As the thermoluminescence spectra analysis of the Eu 2+ -doped CaF 2 has shown the Eu 2+ luminescence [ 21 ], this indicates the thermally activated recombination of F-type centers with Eu 2+ stabilized hole centers followed by Eu 2+ radiative emission. During the heating, the electrons are thermally released from the F-type centers and recombine with holes trapped as Eu 3+ /(Eu 2+ -hole) centers giving rise to the excited (Eu 2+ )* ions and radiative emission according to the reaction [ 51 ]: (Eu 2+ -hole) + é – k B T → (Eu 2+ )*→Eu 2+ + h ν (425 nm) …”