Luminescence of Ce3+ ions in strontium haloborates

Luminescence of Ce3+ ions in alkaline earth borophosphates

“…This scheme implies that in samples with relatively high concentrations of Ce 3+ a single cation vacancy will compensate one Ce 3+ ion locally and one Ce 3+ distantly. Such a mechanism was reported before for SrB 4 O 7 :Ce 3+ [21] and Sr 2 B 5 O 9 X:Ce 3+ (X = Cl, Br) [13,22]. In the other type, the charge compensation is provided by an interstitial oxygen ion (O i ).…”

Valence States and Luminescence Properties of Ytterbium Ions in Strontium Haloborates

“…Between 8 and 16 eV, the emission intensity continues to increase with increasing excitation energy. Note that in the 7}18 eV region the excitation spectrum is similar to that for Sr B O X doped with either Ce> (8) or Eu> (9). Figure 4 shows the time-resolved excitation spectra of the UV emission at 350 nm of Sr \V Yb V B O Cl (x"0.01) after annealing at 7003C for 2 h in air.…”

“…When Yb> ions are doped into strontium haloborates they substitute for strontium ions and therefore require charge compensation to maintain the overall charge neutrality of the crystal. In our previous work on Ce> in these host lattices (8) it was found that the dominant charge compensation mechanism in Sr B O X : Ce> (X"Cl, Br) solid solutions includes the formation of one vacancy per two rare-earth ions incorporated. This process can be described by the KroK ger}Vink notation:…”

“…The strong resemblance between the emission and UV excitation spectra for Sr B O X : Yb> (X"Cl, Br) indicates that the energy position of the Yb>-levels in strontium haloborates is mainly determined by the in#uence of neighboring oxygen ions belonging to the borate groups, and not by the two halogen ions. For Ce> and Eu> ions in these host lattices, the stronger nephelauxetic e!ect of Br\ in comparison with Cl\ causes the shift to longer wavelengths of the excitation and emission bands of the impurity ions in the bromoborates compared to the chloroborates (8).…”

Photoluminescence of Ce3+ in haloapatites Ca5(PO4)3X

“…Because, the unshielded 5d excited state is strongly influenced by the crystal field, the symmetry of local crystal field may induce splitting of d-orbital and, consequently, influence the emission wavelengths and intensity of the materials. Hence, the luminescence properties of Ce 3þ ions in different matrices have been studied extensively [2][3][4][5][6]. Materials doped with Ce 3þ ions have attractively considerable interests due to applications as phosphors, scintillators for elementary particles, detectors for ionizing radiation, UV absorbing filter or UV emitters.…”