A Single-Phase Emission-Tunable Ca5(PO4)3F:Eu2+,Mn2+ Phosphor with Efficient Energy Transfer for White LEDs

Eu2+/Mn2+-co-doped white-emitting Ca-5(PO4)(3)F phosphors have been synthesized by a combustion-assisted synthesis method. The PXRD patterns confirmed the single-phase fluorapatite crystal structure for all the samples independently of their substitution level. Their luminescence properties reveal that the developed phosphors can efficiently convert UV light in a broad range from 250 to 420 nm into tunable white emission. Based on the luminescence spectra and fluorescence decay curves, we can confirm that energy trans-fer from the Eu2+ to Mn2+ ions takes place in the Ca5(PO4) 3F: Eu2+, Mn2+ phosphors, and that the energy-transfer efficiency increases with increasing Mn2+ content. The emission colors of the obtained phosphors can be tuned from blue to white and eventually to yellow by controlling the doping content of the Eu2+ and Mn2+ ions. These results suggest that these phosphors are potential single-component white-light phosphors for n-UV-pumped white LEDs.