Y3Al5O12 garnet (YAG) phosphor co-doped with Terbium (Tb) and Magnesium (Mg) has been investigated. Tb3+ ions have a strong trend to transform into Tb4+ ions under an oxidizing atmosphere. Therefore, this study focused on the effects of structure and optical property of YAG co-doped with Tb4+ + Mg2+ in dodecahedral sites. Spherical phosphor particle is considered better than irregular-shaped particle to improve synthesis. Experimentally, solid reactants were mixed with pH-control and spherical particles were obtained using a spray-drying processing. YAG:Tb and YAG:(Tb, Mg) phosphors were synthesized under an attached air by this solid-state reaction method. When MgO is reached to 2.5 at.%, the MgAl2O4 phase is formed. The cell parameters are reduced by more MgO amount and a longer soaking time. However, a substitution limit of MgO (2.5 at.%) was observed because of the retarding phenomenon at cell parameters. MgO co-doping damaged the grain growth behavior and caused weaker emitting intensities than single-doped YAG:Tb phosphors. Tb4+ ions were also induced by MgO co-doping and this paper provided an explanation about Tb4+ in PL emission spectral analysis.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry