XPS analysis and luminescence mechanism of white SrZn2(PO4)2:Eu2+,Mn2+ phosphor with In3+ sensitizer

• Ligand fields around Sr2+ and Mn2+ varied, while those around Zn2+ and Eu2+ remained stable.
• Doping with In3+ created traps of charged species and clustered pairs in the phosphor.
• Carriers stored temporarily in traps then migrated to Eu2+ to yield an enhanced Eu2+ emission.

The influence of In3+ doping on the binding energy of ions and the energy transfer mechanism of white SrZn2(PO4)2:Eu2+,Mn2+ phosphor was investigated. The ligand fields around Sr2+ and Mn2+ varied with different kinds of doped ions, while those around Zn2+ and Eu2+ remained stable. Doping with In3+ created traps of charged species and clustered pairs in the phosphor. These traps captured excited carriers, leading to a decrease in energy transfer from Eu2+ to Mn2+ and a decline in Mn2+ emission. However, carriers stored temporarily in traps then migrated to Eu2+ to yield an enhanced Eu2+ emission. The phosphor emission was blue-shifted by the increase in In3+ concentration. Maximum Eu2+ energy absorption and emission were obtained when doped with 12 mol% of In3+. The decay time of the phosphor was 11.74 ms.