Photoluminescence, energy transfer, color tunable properties of Sr₃La(BO₃)₃:Ce, Tb phosphors

A series of blue-green color tunable Sr₃La(BO₃)₃:Ce, Tb phosphors were prepared via a solid-state reaction method. The characterizations of X-ray diffraction (XRD), photoluminescence properties, the diffuse reflectance spectra (DRS), the decay curves, energy transfer mechanism and color tunable properties were investigated in detail. As Ce³⁺ ions single doped in Sr₃La(BO₃)₃, the phosphor presents intense light blue under n-UV excitation. As for Sr₃La(BO₃)₃:Ce, Tb, with the increase of the concentration of Tb³⁺, the emission intensity of Tb³⁺ characteristic wavelength increased and that of Ce³⁺ deceased at the same time. By comparing the decay curves of Sr₃La(BO₃)₃:0.03Ce, y Tb, the results indicated that energy transfer existed between Ce³⁺ and Tb³⁺, the energy transfer efficiency reached 91.57% when y = 0.5. The energy transfer mechanism from Ce³⁺ to Tb³⁺ in Sr₃La(BO₃)₃ was demonstrated to be dipole-quadrupole and the critical distance was calculated to be 7.6295 Å∼10.1741 Å by Dexter's energy transfer theory. Those results indicated that the color tunable Sr₃La(BO₃)₃:Ce, y Tb phosphors can be a potential green-emitting candidate for w-LEDs under n-UV. - Highlights: • Sr₃La(BO₃)₃:Ce, Tb is a blue-green color tunable phosphor. • Effective energy transfer Ce→Tb existed in Sr₃La(BO₃)₃:Ce, Tb phosphor. • The ET mechanism of Ce→Tb in Sr₃La(BO₃)₃ was proved to be dipole-quadrupole.