Color-tunable, single phased BaLa2−x−yZnO5: xBi3+, yEu3+ phosphors with efficient energy transfer under ultraviolet excitation

Abstract Color-tunable phosphors BaLa 2− x − y ZnO 5 : x Bi 3+ , y Eu 3+ (0≤ x ≤0.2, 0≤ y ≤0.5) were prepared through solid state reaction. The structure, luminescence properties and the energy transfer from Bi 3+ to Eu 3+ are investigated in detail. Bi 3+ in BaLa 2 ZnO 5 emits blue light in a broad band peaking at 412 nm, which is attributed to the transition from excited state 3 P 1 to ground state 1 S 0 under the excitation of near-ultraviolet (N-UV) light with a wavelength of 312 nm. Eu 3+ in BaLa 2 ZnO 5 emits red light. The co-doping of small amount of Bi 3+ into Eu 3+ doped BaLa 2 ZnO 5 can realize brighter red light attributed to the energy transfer from Bi 3+ to Eu 3+ . The color-tunable emission can be found by adjusting the amount of Eu 3+ in BaLa 1.99−y ZnO 5 : 0.01Bi 3+ , y Eu 3+ phosphors. The decay curves of Bi 3+ were measured to understand the energy transfer processes better, and further the energy-transfer probability and efficiency from Bi 3+ to Eu 3+ on the Bi 3+ concentration were calculated.