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

Abstract

The systems Y3-xCexA15012, Ys-~CexA15-zGazO12, and Y3-x-zGdzCexA15012 were studied. It was found that the solid solubility of Ce 3 § in Y3A15012 varies with the atmosphere during firing. Only 2 mole per cent (m/o) of Ce ~ § can be dissolved in the yttrium aluminum garnet in air while almost 6% Ce 3 § enters the garnet lattice when fired at 1450~ under a hydrogen atmosphere. Complete solid solutions were observed in the systems Y3A15Ol~-Gd~A15012 and Y3A15012-Y3GasO12. The cathodoluminescence emission-peak position of the Ce 3 § ion in Y~A15012 host shifted to a longer wavelength while the latttice parameter of the solid solution expanded when Gd 3. ions were substituted for y3 § On the other hand, the emission-peak position shifted to a shorter wavelength when the garnet host contained Ga s § ions in the A13 § position. The lattice parameter of the solid solution increased with Ga concentration. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 169.230.243.252 Downloaded on 2015-03-24 to IP Vol. 120, No. 2 Ce s § ACTIVATED Y3A15Ol~ 281

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

“…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+…”

“…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.…”

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

“…[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.…”

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

“…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.…”