Ce3+ Activated Y[sub 3]Al[sub 5]O[sub 12] and Some of Its Solid Solutions

Tien, T. Y.; Gibbons, E. F.; DeLosh, R. G.; Zacmanidis, P. J.; Smith, David Eugene; Stadler, H. L.

doi:10.1149/1.2403436

Cited by 132 publications

(86 citation statements)

References 4 publications

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“…3 Gd 3+ and La 3+ in Ce:YAG shift the yellow luminescence of Ce 3+ to longer wavelengths (red shift), 8,9 and, on the contrary, Ga 3+…”

Section: Introductionmentioning

confidence: 99%

“…12 Optically active Ce 3+ impurities are known to substitute for Y 3+ at D 2 (c) sites. 1,9 These sites are also occupied by inactive Lu 3+ , Gd 3+ , and La 3+ red shift inducing impurities 5,9,13 , whereas Ga 3+ and In 3+ blue shift leading impurities substitute for Al 3+ ions. 5 A necessary condition in order to understand the factors that govern how the Ce:YAG luminescence depends on codoping and, ultimately, to be able to control the color of the Ce:YAG: phosphor via codoping, is to acquire a detailed knowledge of the local structures of the double or multiple substitutional defects at the atomistic level, as well as of their electronic structures.…”

Section: Introductionmentioning

confidence: 99%

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Ce and La Single- and Double-Substitutional Defects in Yttrium Aluminum Garnet: First-Principles Study

Muñoz‐García

Seijo

2011

J. Phys. Chem. A

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The atomistic structure, energetics, and electronic structure of single substitutional Ce and La defects and double substitutional Ce-La defects in Ce,La-codoped yttrium aluminum garnet (YAG) Y 3 Al 5 O 12 have been studied by means of first-principles periodic boundary conditions density-functional theory calculations. Single substitution of Y by Ce or by La produces atomistic expansions around the impurities which are significantly smaller than the ionic radii mismatches and the overall lattice distortions are found to be confined within their second coordination spheres.In double substitutional defects, the impurities tend to be as close as possible. La-codoping Ce:YAG provokes an anisotropic expansion around Ce defects. The Ce impurity introduces 4f occupied states in the 5.0 eV computed gap of YAG, peaking 0.25 eV above the top of the valence band, and empty 4f , 5d, and 6s states starting at 3.8 eV in the gap and spreading over the conduction band.La-codoping produces very small effects on the electronic structure of Ce:YAG, the most visible one being the decrease of covalent bonding with one of the oxygen atoms, which shifts 0.05Å away from Ce and gets 0.04Å closer to La in the most stable Ce-La double substitutional defect.

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“…3 Gd 3+ and La 3+ in Ce:YAG shift the yellow luminescence of Ce 3+ to longer wavelengths (red shift), 8,9 and, on the contrary, Ga 3+…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ce and La Single- and Double-Substitutional Defects in Yttrium Aluminum Garnet: First-Principles Study

Muñoz‐García

Seijo

2011

J. Phys. Chem. A

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“…[4][5][6][7] Codopants are long ago known to be able to act as co-activators 6 and as wavelength shifters. 1,[8][9][10] In the case of Ce:YAG, Gd 3+ and La 3+ are known to shift the 5d → 4f yellow luminescence of the Ce 3+ defects to longer wavelengths (red shift), whereas codoping with Ga 3+ and In 3+ shifts the luminescence to shorter wavelengths (blue shift). 1,4,[8][9][10] The effects of these codopants on the 4f → 5d absorptions have not deserved the same attention as the luminescence.…”

Section: Introductionmentioning

confidence: 99%

Structural effects and4f−5dtransition shifts induced by La codoping in Ce-doped yttrium aluminum garnet: First-principles study

et al. 2010

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According to first-principles calculations performed on Ce-doped and Ce,La-codoped yttrium aluminum garnet (YAG) Y 3 Al 5 O 12 , the effect of La-codoping on the local structure around Ce defects in Ce:YAG is an anisotropic expansion in overall, in opposition to recent propositions of local lattice compression. Its effect on the lowest Ce 3+ 4f → 5d transition is found to be a red shift, in agreement with experiments. The red shift is the result of a decrease of the difference between the energy centroids of the 5d 1 and 4f 1 configurations and an increase of the effective ligand field on the Ce-5d shell associated with electronic effects of La substituting for Y. These effects are mitigated by the ligand field decrease associated with the local expansion around Ce, which gives a blue shift contribution of a smaller value. The behavior of the energy difference between the centroids of the configurations cannot be anticipated by the usual model for this quantity, in spite of its usefulness to rationalize 5d → 4f luminescences. The second 4f → 5d transition is found to be blue shifted upon La-codoping, also in agreement with experiments.

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“…and La 3+ co-doped Ce:YAG, combined periodic-boundary-conditions density-functionaltheory 25,26 (DFT) calculations and embedded-cluster CASSCF/CASPT2 calculations reproduced the opposite shifts experienced with both co-dopings 14,15 (blueshift with Ga 3+ and redshift with La 3+ ) and answered the long standing question of why they are opposite if both co-dopings induce lattice expansions 27,28 : The Ga Al defect does not have a preference to sit near Ce and its effects are dominated by the reduction of the ligand field splitting of the 5d shell due to the structural expansion, resulting in a blueshift of the lowest 4f −5d transition.…”

Section: Introductionmentioning

confidence: 87%

Antisite defects in Ce-doped YAG (Y3Al5O12): first-principles study on structures and 4f–5d transitions

2012

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The interactions between Ce 3+ and antisite defects (AD) in YAG (Y 3 Al 5 O 12 ) are studied by means of first-principles calculations: Periodic-boundary-conditions density-functional-theory for a 160 atom YAG unit cell with one Ce 3+ and one or two ADs, and complete-active-space secondorder perturbation theory for the 4f 1 , 5d 1 , and 6s 1 electronic manifolds of the (CeO 8 Al 2 O 4 ) 15− embedded cluster. Attractive interactions are found between Ce 3+ and the ADs. The formation of one AD is more favorable in Ce:YAG than in YAG, but the formation of a second AD is less favorable, which means that the presence of Ce tends to lower the concentration of antisite defects in YAG. The interaction between Ce 3+ and antisite defects blueshifts the two lowest Ce 3+ 4f → 5d transitions. This result rules out the involvement of antisite defects in the recently reported excitation of the lowest 5d → 4f emission with photons below the zero-phonon line and leaves other distorted Cerium centers for consideration, like Ce 3+ interacting with interstitial nonstoichiometric Yttrium or with vacancies. The reasons behind the blueshifts are analyzed in detail:They are dominated by a decrease in the effective ligand-field splitting of the 5d 1 manifold, almost entirely due to the structural changes of short-and long-range and with almost negligible electronic effects from the Y and Al site exchanges.

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Ce3+ Activated Y[sub 3]Al[sub 5]O[sub 12] and Some of Its Solid Solutions

Cited by 132 publications

References 4 publications

Ce and La Single- and Double-Substitutional Defects in Yttrium Aluminum Garnet: First-Principles Study

Ce and La Single- and Double-Substitutional Defects in Yttrium Aluminum Garnet: First-Principles Study

Structural effects and4f−5dtransition shifts induced by La codoping in Ce-doped yttrium aluminum garnet: First-principles study

Antisite defects in Ce-doped YAG (Y3Al5O12): first-principles study on structures and 4f–5d transitions

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