Luminescence properties, energy transfer and thermal stability of blue-green color tunable Sr3Y(BO3)3:Ce3+, Tb3+ phosphors

Abstract

In this paper, a class of blue-green tunable Sr3Y(BO3)3:Ce3+, Tb3+ phosphors were synthesized by the high-temperature solid phase reaction. Their XRD patterns, luminescence properties, energy transfer mechanisms, fluorescence lifetime, luminescence quantum efficiency, and thermally stable properties were researched in detail. At the excitation wavelength of 338 nm, Sr3Y(BO3)3:xCe3+ phosphors appeared intense blue light and the critical quenching concentration was x = 0.07. The studied phosphors could tune from blue to green by changing the Ce3+/Tb3+ ratio. From analyzing the luminescence spectra and fluorescence lifetime of the Sr3Y(BO3)3:Ce3+, Tb3+ phosphors, the energy transfer mechanism in the phosphors was the dipole-dipole. According to the calculation, the effective energy transfer reached to 86.5% when doped 0.5 mol Tb3+ and the critical distance was to 13.718 Å by spectral overlap method. Moreover, Sr2.93Y0.85(BO3)3:0.07Ce3+, 0.15Tb3+ phosphors were less sensitive to the thermal effect and the emission intensity at 373 K is 70% of that at room temperature. All results indicated that the Sr3Y(BO3)3:Ce3+, Tb3+ phosphors were one of the most essential candidates in phosphor-converted white LEDs.