Effect of Al/Ga Substitution on Photoluminescence and Phosphorescence Properties of Garnet-Type Y₃Sc₂Ga3–xAlxO₁₂:Ce³⁺ Phosphor

Garnet-type Y 2.96 Sc 2 Ga 3– x Al x O 12:0.04Ce 3+ ( x = 0–3) phosphors have been prepared by using the high temperature solid-state reaction. Al/Ga ratio dependent Y 3 Sc 2 (Ga,Al) 3 O 12 phase structures, photoluminescence (PL) properties, and long-lasting phosphorescence (LLP) properties for the Ce 3+ -doped phosphors have been investigated in detail. The PL emission bands of Y 2.96 Sc 2 Ga 3– x Al x O 12:0.04Ce 3+ showed a red-shift tendency gradually from 503 to 520 nm with increasing Al content ( x value), and the emission intensities increased first, maximized at x = 1, and then decreased. Y 3 Sc 2 Ga 3 O 12:Ce 3+ can show the green LLP emission, and afterglow can be obviously enhanced when (1) Al ions replaced Ga ions for a small amount and (2) the reaction atmosphere was varied from reducing to oxidation one. The afterglow emission, decay curves, and thermoluminescence (TL) of Y 2.96 Sc 2 Ga 3– x Al x O 12:0.04Ce 3+ ( x = 0–0.7) phosphors have been investigated, and related luminescence mechanisms are systematically discussed as well.