Synthesis and photoluminescence enhancement of Ca3Sr3(VO4)4:Eu3+ red phosphors by Sm3+ doping for white LEDs

A new type of red-emitting Eu 3+ and Sm 3+ co-doped Ca 3 Sr 3 (VO 4 ) 4 phosphor was synthesized by the combustion method. The photoluminescence properties and microstructure were investigated by photoluminescence spectroscopy, X-ray powder diffraction, and scanning electron microscopy. All samples were found to match perfectly with the rhombohedral structure and belong to the R 3 c space group. The photoluminescence emission intensity of the optimal phosphor Ca 3 Sr 3 (VO 4 ) 4 :0.05Eu 3+ , 0.09Sm 3+ at 619 nm was significantly enhanced compared with those of Ca 3 Sr 3 (VO 4 ) 4 :Eu 3+ samples and commercial Y 2 O 3 :Eu 3+ at an excitation wavelength of 393 nm, as a result of the energy transfer from Sm 3+ to Eu 3+ . The energy transfer process between Sm 3+ and Eu 3+ is discussed and interpreted by considering the energy level diagram. Furthermore, the CIE chromaticity coordinate of Ca 3 Sr 3 (VO 4 ) 4 :0.05Eu 3+ , 0.09Sm 3+ was closer to the standard red-emitting point ( x = 0.67, y = 0.33) than Y 2 O 3 :Eu 3+ . The luminescence performance of Ca 3 Sr 3 (VO 4 ) 4 :Eu 3+ , Sm 3+ upon excitation by near-UV radiation makes it a promising red phosphor for manufacturing white-light-emitting diodes.