Synthesis and luminescent properties investigation of novel red emission phosphors Ca7Zn2(PO4)6: Re3+ (Re =Eu, Sm and Pr)

Abstract A series of new red emission phosphors Ca 7 Zn 2 (PO 4 ) 6 : Re 3+ (Re 3+  = Eu 3+ , Sm 3+ , Pr 3+ ) are synthesized by solid state reaction. The crystal structure and microstructure are systematically investigated by X-ray diffraction Rietveld structure refinement, scanning electron microscopy and energy dispersive spectrometer. The photoluminescence properties of Ca 7 Zn 2 (PO 4 ) 6 : Re 3+ (Re 3+  = Eu 3+ , Sm 3+ , Pr 3+ ) are studied in detail. The results show that Eu 3+ , Sm 3+ or Pr 3+ single doped Ca 7 Zn 2 (PO 4 ) 6 could emit red emissions with dominate peaks at 612 nm, 602 nm and 612 nm, respectively, which are attributed to the characteristic transitions ( 5 D 0 - 7 F 2 , 4 G 5/2 - 6 H 7/2 and 3 P 0 - 3 H 6 ) of Eu 3+ , Sm 3+ and Pr 3+ . The concentration dependent emission spectra of Ca 7 Zn 2 (PO 4 ) 6 : Sm 3+ are studied as well. A charge compensator Li 2 CO 3 is added in Sm 3+ doped Ca 7 Zn 2 (PO 4 ) 6 and the emission intensity is compared with the commercial red phosphor Y 2 O 3 :Eu 3+ . The room temperature fluorescence lifetimes of Ca 7 Zn 2 (PO 4 ) 6 : Re 3+ (Re 3+  = Eu 3+ , Sm 3+ , Pr 3+ ) are measured and the average lifetimes are evaluated. Finally, the Commission Internationale de L'Eclairage chromaticity coordinates and their color purity are calculated.