Blue-green tunable color of Ce ³⁺/Tb ³⁺ coactivated NaBa ₃La ₃Si ₆O ₂₀ phosphor via energy transfer

Abstract

A series of color tunable phosphors NaBa ₃La ₃Si ₆O ₂₀:Ce ³⁺, Tb ³⁺ were synthesized via the high-temperature solid-state method. NaBa ₃La ₃Si ₆O ₂₀ crystallizes in noncentrosymmetric space group Ama2 with the cell parameters of a = 14.9226(4) Å, b = 24.5215(5) Å and c = 5.6241(2) Å by the Rietveld refinement method. The Ce ³⁺ ions doped NaBa ₃La ₃Si ₆O ₂₀ phosphors have a strong absorption band from 260 to 360 nm and show near ultraviolet emission light centered at 378 nm. The Ce ³⁺ and Tb ³⁺ ions coactivated phosphors exhibit color tunable emission light from deep blue to green by adjusting the concentration of the Tb ³⁺ ions. An energy transfer of Ce ³⁺ → Tb ³⁺ investigated by the photoluminescence properties and lifetime decay, is demonstrated to be dipole–quadrupole interaction. These results indicate the NaBa ₃La ₃Si ₆O ₂₀:Ce ³⁺, Tb ³⁺ phosphors can be considered as potential candidates for blue-green components for white light emitting diodes.