Optical properties and energy transfer of Eu2+/Ce3+ co-activated Na3Ca6(PO4)5 phosphor

Ce(3+) /Eu(2+) co-doped Na3 Ca6 (PO4 )5 phosphors were prepared using a combustion-assisted synthesis method. X-Ray powder diffraction (XRD) analysis confirmed the formation of a Na3 Ca6 (PO4 )5 crystal phase. Na3 Ca6 (PO4 )5 :Eu(2+) phosphors have an efficient bluish-green emission band that peaks at 489 nm, whereas Ce(3+) -doped Na3 Ca6 (PO4 )5 showed a bright emission band at 391 nm. Analysis of the experimental results suggests that enhancement of the Eu(2+) emission intensity in co-doped Na3 Ca6 (PO4 )5 :Eu(2+) ,Ce(3+) phosphors is due to a resonance-type energy transfer from Ce(3+) to Eu(2+) ions, which is predominantly governed by an exchange interaction mechanism. These results indicate that Ce(3+) /Eu(2+) co-doped Na3 Ca6 (PO4 )5 is potentially useful as a highly efficient, bluish-green emitting, UV-convertible phosphor for white-light-emitting diodes.