Novel orange-yellow-green color-tunable Bi3+-doped Ba3Y4−wLuwO9 (0 ≤ w ≤ 4) luminescent materials: site migration and photoluminescence control

Abstract

A novel orange-yellow-emitting Ba₃Y₄O₉:Bi³⁺ phosphor (550 nm) has been firstly discovered. Meanwhile, we report isomorphic Ba₃Lu₄O₉:Bi³⁺ with green emission (526 nm). Based on the cation substitution strategy, a series of Ba₃Y_4−wLu_wO₉:Bi³⁺ (0 ≤ w ≤ 4) solid solution phases are successfully constructed, realizing consecutive photoluminescence control from orange-yellow to green light. The occurrence of site migration of Bi³⁺ ions from Y2/Lu2 and Y4/Lu4 to Y1/Lu1 and Y3/Lu3 sites results in the blueshift of Ba₃Y_4−wLu_wO₉:Bi³⁺ (0 ≤ w ≤ 4), which is confirmed by the linear increase of PL intensity I₍₁₊₃₎/I₍₂₊₄₎ with the substitution of Lu³⁺ ions for Y³⁺ ions. Besides, the improved thermal stability of Ba₃Y_4−wLu_wO₉:Bi³⁺ (0 ≤ w ≤ 4) with the substitution of Lu³⁺ for Y³⁺ originates from the better structure rigidity. The fabricated white light-emitting diodes (WLEDs) exhibit excellent warm white light, indicating that the as-prepared Ba₃Y_4−wLu_wO₉:Bi³⁺ (0 ≤ w ≤ 4) phosphors can act as a green to yellow emitting component in WLED lighting.