Effect of polyethylene glycol on luminescence properties and morphologies of BaAl2Si2O8:Eu2+ phosphors

Eu²⁺-doped BaAl₂Si₂O₈ blue phosphor was prepared by the one-step calcination process of the chemical coprecipitation method. The phase structure, luminescence properties and morphologies of the samples were investigated by X-ray powder diffraction, fluorescence spectrophotometer and scanning electron microscopy, respectively. A tiny amount of BaAl₂O₄ phase was detected after adding polyethylene glycol (PEG) in precursor solution. The emission intensity increased with increasing PEG concentration at the beginning, and then decreased owing to the adverse enhancement of impurity phase and concentration quenching of Eu²⁺ ions resulted from addition of PEG. The emission peak position of the sample with 4 wt% PEG has a blue-shift compared with the other concentrations, which is attributed to Eu²⁺ emission mainly influenced by the Nephelanxetic effect. The morphology of particles changed from platelet or block to subglobular with increasing PEG concentration because PEG changed a nucleation process of crystal and gave rise to steric hindrance effect.