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Recent progress in advanced optical materials based on gadolinium aluminate garnet (Gd 3 Al 5 O 12 )

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ABSTRACT

This review article summarizes the recent achievements in stabilization of the metastable lattice of gadolinium aluminate garnet (Gd3Al5O12, GAG) and the related developments of advanced optical materials, including down-conversion phosphors, up-conversion phosphors, transparent ceramics, and single crystals. Whenever possible, the materials are compared with their better known YAG and LuAG counterparts to demonstrate the merits of the GAG host. It is shown that novel emission features and significantly improved luminescence can be attained for a number of phosphor systems with the more covalent GAG lattice and the efficient energy transfer from Gd3+ to the activator. Ce3+ doped GAG-based single crystals and transparent ceramics are also shown to simultaneously possess the advantages of high theoretical density, fast scintillation decay, and high light yields, and hold great potential as scintillators for a wide range of applications. The unresolved issues are also pointed out.

No MeSH data available.


A schematic illustration of the crystal structure of LnAG, where Aloct and Altet represent the Al atoms taking octahedral and tetrahedral lattice sites, respectively. Adapted with permission from [1], copyright 1999 by the American Physical Society.
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Figure 1: A schematic illustration of the crystal structure of LnAG, where Aloct and Altet represent the Al atoms taking octahedral and tetrahedral lattice sites, respectively. Adapted with permission from [1], copyright 1999 by the American Physical Society.

Mentions: Rare-earth aluminate garnets, having a general formula of Ln3Al5O12 (LnAG, Ln: lanthanide and Y), are an important family of multi-functional ceramic materials. The compounds crystallize in a bcc structure (space group: with 160 (80) atoms in the cubic (primitive) cell, where the Ln occupies the 24c sites (D2 point symmetry, CN = 8; CN: coordination number) and the oxygen atoms take the 96h sites. The Al atoms have two positions to reside on: the 16a sites with an octahedral point symmetry (C3i, 40%; CN = 6) and the 24d sites with a tetragonal point symmetry (S4, 60%; CN = 4) [1]. The garnet structure can be viewed as a framework built up via corner sharing of the Al–O polyhedra, with the Ln residing in dodecahedral interstices [1]. A schematic diagram of the crystal structure is shown in figure 1.


Recent progress in advanced optical materials based on gadolinium aluminate garnet (Gd 3 Al 5 O 12 )
A schematic illustration of the crystal structure of LnAG, where Aloct and Altet represent the Al atoms taking octahedral and tetrahedral lattice sites, respectively. Adapted with permission from [1], copyright 1999 by the American Physical Society.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5036492&req=5

Figure 1: A schematic illustration of the crystal structure of LnAG, where Aloct and Altet represent the Al atoms taking octahedral and tetrahedral lattice sites, respectively. Adapted with permission from [1], copyright 1999 by the American Physical Society.
Mentions: Rare-earth aluminate garnets, having a general formula of Ln3Al5O12 (LnAG, Ln: lanthanide and Y), are an important family of multi-functional ceramic materials. The compounds crystallize in a bcc structure (space group: with 160 (80) atoms in the cubic (primitive) cell, where the Ln occupies the 24c sites (D2 point symmetry, CN = 8; CN: coordination number) and the oxygen atoms take the 96h sites. The Al atoms have two positions to reside on: the 16a sites with an octahedral point symmetry (C3i, 40%; CN = 6) and the 24d sites with a tetragonal point symmetry (S4, 60%; CN = 4) [1]. The garnet structure can be viewed as a framework built up via corner sharing of the Al–O polyhedra, with the Ln residing in dodecahedral interstices [1]. A schematic diagram of the crystal structure is shown in figure 1.

View Article: PubMed Central - PubMed

ABSTRACT

This review article summarizes the recent achievements in stabilization of the metastable lattice of gadolinium aluminate garnet (Gd3Al5O12, GAG) and the related developments of advanced optical materials, including down-conversion phosphors, up-conversion phosphors, transparent ceramics, and single crystals. Whenever possible, the materials are compared with their better known YAG and LuAG counterparts to demonstrate the merits of the GAG host. It is shown that novel emission features and significantly improved luminescence can be attained for a number of phosphor systems with the more covalent GAG lattice and the efficient energy transfer from Gd3+ to the activator. Ce3+ doped GAG-based single crystals and transparent ceramics are also shown to simultaneously possess the advantages of high theoretical density, fast scintillation decay, and high light yields, and hold great potential as scintillators for a wide range of applications. The unresolved issues are also pointed out.

No MeSH data available.