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.