Highly non-stoichiometric YAG ceramics with modified luminescence properties

21 October 2022, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


Yttrium aluminium garnet Y3Al5O12 (YAG) is a widely used phosphor host. Its optical properties are tuned by chemical substitution at its YO8 or AlO6/AlO4 sublattices, with emission wavelengths defined by a finite number of rare-earth (YO8 sublattice) and transition-metal (AlO6/AlO4 sublattice) dopants which have been explored extensively. Non-stoichiometric compositions Y3+xAl5-xO12 (x ≠ 0) may offer a route to new emission wavelengths by distributing dopants over multiple crystallographic sites, but deviation from Y3Al5O12 stoichiometry is difficult to achieve and limited generally to ≤ 1% excess Y3+. Here we report a series of highly non-stoichiometric YAG ceramics Y3+xAl5-xO12 (0 ≤ x ≤ 0.4), with up to 20% of the AlO6 sublattice substituted by Y3+, synthesised by advanced melt-quenching techniques. This impacts the up-conversion luminescence of Yb3+/Er3+-doped systems, whose yellow-green emission differs from the red-orange emission of their stoichiometric counterparts. This contrasts with YAG:Ce3+ where the dopant ions occupy the YO8 sublattice exclusively, with down-conversion luminescence that is hardly affected by host non-stoichiometry. Beyond YAG, analogous highly non-stoichiometric systems should be obtainable for a range of functional garnets, demonstrated here by the successful synthesis of Gd3.2Al4.8O12 and Gd3.2Ga4.8O12. This opens the way to property tuning by control of garnet host stoichiometry, and the prospect of improved performance or new applications for garnet-type materials.


aerodynamic levitation
powder diffraction
solid state NMR

Supplementary materials

Supporting Information
Supporting information file including: - CSD deposition numbers - Supporting Figures S1-S9 - Supporting Table S1-S3 - Supporting Text (glass characterisation; powder diffraction; STEM; solid state NMR; EXAFS; luminescence; electron microprobe)


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.