Synthesis and spectroscopic investigation of Ba3La6(SiO4)6:Eu2+ green phosphors for white light-emitting diodes

A novel Eu2+-activated Ba3La6(SiO4)6:Eu2+ (BLSO:Eu2+) green-emitting phosphor with strong luminescence has been successfully prepared via a solid state reaction. The crystal structure, photoluminescence (PL) as well as thermal stability properties of BLSO:Eu2+ phosphor are investigated systematically. The BLSO:Eu2+ phosphor exhibits a broad excitation band extending from 250 to 450 nm, and gives an intense asymmetric green emission band centered at 507 nm. Two different Eu2+ emitting centers are identified by their PL spectra and PL decay lifetimes in BLSO:Eu2+ phosphor. The optimal Eu2+ content in BLSO:Eu2+ is confirmed to be 5 mol%, and the corresponding concentration quenching mechanism is determined to the electric dipole-dipole interaction. Moreover, compared to the initial one at room temperature, the PL intensity of the investigated phosphor can maintain 52% as heated up to 423 K. Finally, warm white light emitting diode with a low correlated color temperature of 4818 K and a high color rendering index of 82.9 is achieved by mixing blue/green/red (BaMgAl10O17:Eu2+/BLSO:Eu2+/CaAlSiN3:Eu2+) phosphors with the commercial n-UV-GaN chip. (C) 2016 Elsevier B.V. All rights reserved.