Luminescence and energy transfer of Tm³⁺ and Dy³⁺ co-doped Na₃ScSi₂O₇ phosphors

A series of Tm³⁺ and Dy³⁺ ions single- or co-doped Na₃ScSi₂O₇ (NSSO) phosphors were prepared by a conventional solid state reaction method. The X-ray diffraction (XRD) patterns, photoluminescence (PL) properties, fluorescence decay curve and energy transfer behavior of the samples were studied. The XRD patterns show that all the diffraction peaks of the samples are consistent with the JCPDS standard data. Under UV excitation, the singly doped NSSO phosphors with Tm³⁺ and Dy³⁺ ions show blue and yellow characteristic emission. The emission color of NSSO:Tm³⁺,Dy³⁺ can be adjusted by the corresponding Tm³⁺-Dy³⁺ energy transfer. In addition, the chromaticity coordinate of NSSO:0.04Tm³⁺,0.13Dy³⁺ is (0.3195, 0.3214), which is close to the ideal white light (0.333, 0.33). These results show that NSSO:Tm³⁺,Dy³⁺ has potential application value in white light emitting diodes (WLEDs).