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\nsynthesized via the high-temperature solid-state reaction route. X-ray\ndiffraction, high-resolution transmission electron microscopy, Fourier\ntransform infrared, solid-state NMR, photoluminescence (PL) including\ntemperature-dependent PL, and fluorescent decay measurements were\nconducted to characterize and analyze as-prepared samples. BYSPO was\nobtained by the substitution of Y+SiO₄ for Ba+PO₄ in Ba₃Y­(PO₄)₃ (BYPO). The\nred shift of PL emission from 375 to 401 nm occurs by comparing BYSPO:0.14Ce³⁺ with BYPO:0.14Ce³⁺ under 323 nm UV excitation.\nMore importantly, the excitation edge can be extended from 350 to\n400 nm, which makes it be excited by UV/n-UV chips (330–410\nnm). Tunable emission color from blue to green can be observed under\n365 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\nupon 377 nm UV excitation. Energy transfer properties were demonstrated\nby overlap of excitation spectra, variations of emission spectra,\nand 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\ncoordinates were also presented. Generally, the results suggest their\npotential applications in UV/n-UV pumped LEDs.