Photoluminescence investigations of (Y 1−xLn x) 3Al 5O 12:Ce (Ln 3+=Gd 3+, La 3+) nanophosphors

Abstract

(Y 1− x Ln x ) 3Al 5O 12:Ce (Ln 3+=Gd 3+, La 3+) phosphors were synthesized by in situ esterification. The effects of Gd 3+ and La 3+ ions on structure and luminescence of YAG:Ce were investigated. For Gd 3+-doped YAG:Ce, when doping concentration increased beyond 50 mol%, GdAlO 3 phase appeared. For La 3+-doped YAG:Ce, as doping concentration increased beyond 20 mol%, YAG phase completely disappeared and LaAlO 3 phase emerged. As the doping concentration of Gd 3+ and La 3+ increased, the maximum emission band showed red shift. Because radii of Gd 3+ and La 3+ were larger than that of Y 3+, Gd 3+ and La 3+ replacement distorted YAG structure. More defects are formed in (Y 1− x Ln x ) 3Al 5O 12:Ce, which acts as quenching center. Therefore, emission intensity of (Y 1− x Ln x ) 3Al 5O 12:Ce was lower than YAG:Ce and luminescent lifetime of (Y 1− x Ln x ) 3Al 5O 12:Ce was shorter than YAG:Ce.