Photoluminescence and Energy Transfer Properties with Y+SiO₄ Substituting Ba+PO₄ in Ba₃Y(PO₄)₃:Ce³⁺/Tb³⁺, Tb³⁺/Eu³⁺ Phosphors for w‑LEDs

Abstract

A series of Ce³⁺, Tb³⁺, Eu³⁺ doped Ba₂Y₂(PO₄)₂­(SiO₄) (BYSPO) phosphors were synthesized via the high-temperature solid-state reaction route. X-ray diffraction, high-resolution transmission electron microscopy, Fourier transform infrared, solid-state NMR, photoluminescence (PL) including temperature-dependent PL, and fluorescent decay measurements were conducted to characterize and analyze as-prepared samples. BYSPO was obtained by the substitution of Y+SiO₄ for Ba+PO₄ in Ba₃Y­(PO₄)₃ (BYPO). The red shift of PL emission from 375 to 401 nm occurs by comparing BYSPO:0.14Ce³⁺ with BYPO:0.14Ce³⁺ under 323 nm UV excitation. More importantly, the excitation edge can be extended from 350 to 400 nm, which makes it be excited by UV/n-UV chips (330–410 nm). Tunable emission color from blue to green can be observed under 365 nm UV excitation based on the energy transfer from Ce³⁺ to Tb³⁺ ions after codoping Tb³⁺ into BYSPO:0.14Ce³⁺. Moreover, energy transfer from Tb³⁺ to Eu³⁺ ions also can be found in BYSPO:Tb³⁺,Eu³⁺ phosphors, resulting in the tunable color from green to orange red upon 377 nm UV excitation. Energy transfer properties were demonstrated by overlap of excitation spectra, variations of emission spectra, and decay times. In addition, energy transfer mechanisms from Ce³⁺ to Tb³⁺ and Tb³⁺ to Eu³⁺ in BYSPO were also discussed in detail. Quantum yields and CIE chromatic coordinates were also presented. Generally, the results suggest their potential applications in UV/n-UV pumped LEDs