Tunable emission and energy transfer in single-phased Ba₉Lu₂Si₆O₂₄:Bi³⁺,Eu³⁺ for UV W-LEDs

A novel single-phased tunable emitting phosphor Ba₉Lu₂Si₆O₂₄:Bi³⁺,Eu³⁺ (BLSO:Bi³⁺,Eu³⁺) was successfully prepared via a simple solid-state approach. The main excitation peaks range from 320 to 400 nm of BLSO:Bi³⁺ were identified by photoluminescence characterization, indicating BLSO:Bi³⁺ viable for ultraviolet (UV) excitation. Emission spectra show that Bi³⁺ occupies at least two nonequivalent sites in BLSO host, and display broad emission peaks at 410 and 490 nm when excited by UV light, respectively. As red emitting center Eu³⁺ was introduced into BLSO:Bi³⁺, significant energy transfer (ET) occurs from Bi³⁺ to Eu³⁺ through a dipole-dipole mechanism. The ET efficiency reaches 97.57%. By varying the doped ratio of Bi³⁺ and Eu³⁺, tunable light and white emission can be easily realized. Results indicate that BLSO:Bi³⁺,Eu³⁺ is a potential tunable emission phosphor in UV excited W-LEDs.