Single-phased white-emitting Ca3Y(GaO)(3)(BO3)(4):Ce3+ ,Tb3+ ,Sm3+ phosphors with high-efficiency: Photoluminescence, energy transfer and application in near-UV-pumped white LEDs

Novel single-phased white-emitting Ca3Y(GaO)(3)(BO3)(4):Ce3+, Tb3+, Sm3+ phosphors with high-efficiency, were successfully synthesized via traditional high temperature solid-state reaction method. X-ray diffraction, luminescence spectroscopy, fluorescence decay time and fluorescent thermal stability tests have been used to characterize the as-prepared samples. The energy transfer among of Ce3+, Tb3+ and Sm3+ ions in Ca3Y (GaO)(3)(BO3)(4) host have been studied in detail. The mechanisms of Ce3+ -> Tb3+ and Ce3+ -> Sm3+ energy transfer were demonstrated to be dipole-dipole interactions. The emission color of the obtained phosphors can be easily tuned by controlling the doping concentration ratios of Ce3+ /Tb3+ /Sm3+. Particularly, under the excitation at 340 nm, Ca3Y(GaO)(3)(BO3)(4):0.01Ce(3+), 0.15Tb(3+), 0.01Sm(3+) phosphor showed bright a white light with CIE coordinates of (0.2892, 0.2943) and internal quantum efficiency as high as 49.5%. By integrating this single-composition white-emitting Ca3Y(GaO)(3)(BO3)(4):0.01Ce(3+), 0.15Tb(3+), 0.01Sm(3+) phosphor with a 365 nm near-ultraviolet (NUV) light emitting diode (LED) chip, we successfully fabricated a prototype white LED (WLED) device, which exhibited high-brightness nearly ideal white light with CIE coordinates of (0.310, 0.330), color rendering index of 72.7 and a correlated color temperature of 6624 K. These results demonstrate that the proposed single-composition white-emitting Ca3Y(GaO)(3)(BO3)(4): Ce3+, Tb3+, Sm3+ phosphors can serve as promising phosphors for the application of NUV-excited WLEDs.