Photoluminescent and thermal properties of (Sr0.995−x−y−zCaxBayMgz)2SiO4:0.01Eu2+ phosphors for warm white light-emitting diodes

A series of phosphors (Sr0.995−x−y−zCaxBayMgz)2SiO4:0.01Eu2+ (0 ≤ x ≤ 0.45, 0 ≤ y ≤ 0.015, 0 ≤ z ≤ 0.35) were synthesized by solid state reaction. Their phase compositions and photoluminescent properties were investigated in detail. The X-ray diffraction analysis indicates the impurity phase of SrSiO3 is formed only when z ≥ 0.25. A photoluminescence investigation shows, with x increasing the emission spectra of the phosphors (0 ≤ x ≤ 0.45, 0 ≤ y ≤ 0.015, z = 0) obviously red-shift, the corresponding color tones shift from yellow to orange–yellow and their CCTs reduce from 2875 to 2237 K. All the results are beneficial for the phosphors to combining blue light-emitting diode chips to generate warm white light. Besides, the thermal stability of the phosphor (x = 0.36, y = z = 0) is enhanced by doping Ba2+, due to the greater activation energy for the compounds containing barium.