The application and a substitution defect model for Eu3+→Eu2+ reduction in non-reducing atmospheres in borates containing BO4 anion groups Original Research Article

The variations of emission intensities of SrB4O7:Eu2+ and Sr2B5O9Cl:Eu2+ prepared in different atmospheres are discussed in view of the structure of host compounds. A model of substitution defects is proposed to explain the abnormal reduction of Eu3+→Eu2+ in non-reducing atmospheres of N2, air and O2. Experiment results show that SrB4O7:Eu2+ phosphor sample prepared in N2 atmosphere has an emission intensity of 94% as high as that of the sample prepared in H2 gas. This implies that the reduction of Eu3+→Eu2+ in non-reducing atmospheres could be potentially used in preparing phosphors, such as SrB4O7:Eu2+.