Luminescence properties and energy transfer of Bi3+/Eu3+-codoped Ca10(PO4)6F2 phosphors

Ca10(PO4)6F2:Bi3+, Eu3+ phosphors have been synthesized by a high temperature solid-state reaction, and their luminescence properties, especially the energy transfer behaviors have been investigated by photoluminescence emission, excitation spectra, and luminescence lifetimes analysis. The obtained spectroscopic data indicate that energy transfer takes place from Bi3+ to Eu3+ ions, and the color-tunable yellow, orange and red emission can be found from the Ca10(PO4)6F2:Bi3+, Eu3+ phosphors with different Bi3+/Eu3+ ratio. The energy transfer efficiency reaches 50.3% for the selected sample, which has the optimized doping concentrations of 2% for Bi3+ and 8% for Eu3+. The energy transfer mechanism from Bi3+ to Eu3+ in the Ca10(PO4)6F2 host was ascribed to the quadrupole–quadrupole interactions