Development of YK₃B₆O₁₂: RE (RE = Eu³⁺, Tb³⁺, Ce³⁺) tricolor phosphors under near-UV light excitation

Polycrystalline phosphors YK₃B₆O₁₂:RE³⁺ (RE = Eu, Ce, Tb) were prepared by the solid-state synthesis. The single crystal-phases of the samples were confirmed by X-ray powder diffraction (XRD) measurements and the structural refinements. The field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and electron dispersive X-ray (EDX) measurements were applied to analyze the morphologies of the phosphors. The photoluminescence excitation spectra (PLE) and emission (PL) spectra, decay curves and lifetimes were investigated. Under the near-UV light excitation, YK₃B₆O₁₂:Eu³⁺, YK₃B₆O₁₂:Ce³⁺, and YK₃B₆O₁₂:Tb³⁺ phosphors exhibit the characteristic emission transitions from Ce³⁺ (5d→4f transitions in blue color), Eu³⁺ (⁵D₀→⁷F₂, red color), and Tb³⁺ (⁵D₄→⁷F₅, green color), respectively. The luminescence internal quantum efficiency (QE), the optimal doping level and the thermal stability with the activation energy (ΔE) were measured. The result in this work could be useful for the further applications of this new host as a potential phosphor. © 2016 Elsevier B.V.