Photoluminescence and energy transfer of a color tunable phosphors: Sr3La(BO3)3:Ln3+ (Ln = Dy, Eu, Tb) for warm white light UV-excited WLEDs

A series of color tunable Sr3La(BO3)3:Ln3+(Ln = Dy, Eu, Tb) phosphors were prepared via solid-state reaction method. The characterizations of X-ray diffraction (XRD), photoluminescence properties, the decay curves and energy transfer mechanism were investigated in detail. The color temperature of Sr3La(BO3)3:Dy, Eu was lower than Sr3La(BO3)3:Dy. The emission color of Sr3La(BO3)3:Tb, Eu was tunable from green to white and orange since the energy transfer of Tb3+ → Eu3+ in phosphors. The energy transfer efficiency reached 53.18% when y = 0.10. The phosphor Sr3La(BO3)3:0.04Tb, 0.04Eu could emit white light, and its correlated color temperature was 3929 K. Under 375 nm excitation, Sr3La(BO3)3:Tb, Eu, Dy emitted white light. What's more, the chromaticity coordinate of Sr3La(BO3)3:0.04Tb, 0.06Eu, 0.04Dy was (0.365,0.338) which was close to the standard white chromaticity coordinate, and its correlated color temperature was 4155 K. Those results indicated that Sr3La(BO3)3:Tb, Eu, Dy may be a potential warm white-emitting candidate for w-LEDs under n-UV excitation.