Luminescence Centers of MgS, CaS and CaSe Phosphors Activated with Eu²⁺ Ion

Abstract

Emission and excitation spectra of Eu 2+ ions incorporated in MgS, CaS and CaSe were measured at temperatures 300, 80 and 6 K. Both spectra are interpreted as due to the allowed transition between the Eu 2+ ion's ground state ( 8 S 7/2 ) of 4f 7 configuration and the excited states of 4f 6 5d configuration, together with the forbidden transition arising from the configuration interaction between 4f 6 5d and4f 6 6s. From the observed excitation spectra for CaS: Eu 2+ and CaSe: Eu 2+ phosphors, \(^{8}\varGamma_{4}(t_{\text{2g}})\)-, \(^{8}\varGamma_{3}(e_{\text{g}})\)-bands were assigned for lower concentrations of Eu 2+ ion; besides these bands \(^{8}\varGamma_{1}(6s)\)- and \(^{6}\varGamma_{4}(t_{\text{2g}})\)-bands were assigned for higher concentrations of Eu 2+ ion. From the assigned \(^{8}\varGamma_{4}(t_{\text{2g}})\)- and \(^{8}\varGamma_{3}(e_{\text{g}})\)-bands, it has been found that 10 D q for MgS, CaS and CaSe are 19500 cm -1 , 18750 cm -1 and 17300 cm -1 , respectively.