Wide Concentration Range of Tb3+ Doping Influence on Scintillation Properties of (Ce, Tb, Gd)3Ga2Al3O12 Crystals Grown by the Optical Floating Zone Method

Abstract

To obtain a deeper understand of the energy transfer mechanism between Ce3+ and Tb3+ ions in the aluminum garnet hosts, (Ce, Tb, Gd)3Ga2Al3O12 (GGAG:Ce, Tb) single crystals grown by the optical floating zone (OFZ) method were investigated systematically in a wide range of Tb3+ doping concentration (1–66 at.%). Among those, crystal with 7 at.% Tb reached a single garnet phase while the crystals with other Tb3+ concentrations are mixed phases of garnet and perovskite. Obvious Ce and Ga loss can be observed by an energy dispersive X-ray spectroscope (EDS) technology. The absorption bands belonging to both Ce3+ and Tb3+ ions can be observed in all crystals. Photoluminescence (PL) spectra show the presence of an efficient energy transfer from the Tb3+ to Ce3+ and the gradually quenching effect with increasing of Tb3+ concentration. GGAG: 1% Ce3+, 7% Tb3+ crystal was found to possess the highest PL intensity under excitation of 450 nm. The maximum light yield (LY) reaches 18,941 pho/MeV. The improved luminescent and scintillation characteristics indicate that the cation engineering of Tb3+ can optimize the photoconversion performance of GGAG:Ce.

First Observation of the Scintillation Cascade in Tb3+‐Doped Quaternary Garnet Ceramics

“…Such excitation provides a relatively high scintillation LY under conditions of strong concentration quenching, for example, in CeF 3 crystals. [10] With a more significant concentration of terbium ions, concentration quenching begins to appear in crystals of mixed garnets, [45] which diminishes the role of shock excitation. A further increase in the efficiency of the scintillation cascade, apparently, should be sought in the further adjustment of the composition of the compound to increase the efficiency of cross-relaxation.…”

Micro-Inclusion Engineering via Sc Incompatibility for Luminescence and Photoconversion Control in Ce3+-Doped Tb3Al5−xScxO12 Garnet

“…Aluminum garnets belong to the group of multifunctional materials due to their exceptional structural stability and compositional flexibility [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. This group of compounds exhibits a high degree of tolerance for doping ability and readily accepts a wide range of rare earth and/or transition metals [ 4 , 8 , 9 , 12 ].…”

“…This translates to a significant simplification of the crystal growth process from the melt and transparent ceramics sintering process, as the lattice structure does not change the phase during solidification, leading to crack-free material with high mechanical strength [ 2 , 3 , 8 , 9 ]. Therefore, aluminum garnets are important materials in diverse fields, including laser materials [ 14 ], scintillators [ 2 , 15 ], persistent luminescence phosphors [ 9 , 10 ], and photoconverters [ 1 , 8 , 11 ].…”

“…One frequent approach to tuning the emission color of Ce 3+ -doped Y 3 Al 5 O 12 involves the substitution of yttrium with other rare-earth elements within the Y 3 Al 5 O 12 crystal lattice. This tune involves either the partial or complete replacement of Y 3+ sites with larger cations, such as La 3 ⁺, Gd 3 ⁺, or Tb 3 ⁺, which typically results in a shift of the emission band towards longer wavelengths [ 1 , 2 , 11 , 16 , 18 ].…”

Nd:YAG Single Crystals Grown by the Floating Zone Method in a Laser Furnace

“…Moreover, the metallic materials are very sensitive to residual oxygen at high temperatures that reserve the growth processes only in an inert or reducing environment, although the work in pure oxygen under the pressure can significantly improve the optical properties of the oxide-based single crystals. 15 Our work primarily focuses on single crystal growth of scintillators and solid-state lasers based on a garnet structure derived from yttrium-aluminum garnet (YAG). The substituted variants of laser materials Nd:YAG, 16 Er:YAG, 17 Yb:YAG, 18 Tm:YAG, 19 or scintillator (Ce:YAG 20 ) have found very broad applications.…”