Tuning of multicolor emissions in glass ceramics containing γ-Ga2O3 and β-YF3 nanocrystals

A novel tunable emitting glass ceramic containing beta-YF3:Tm3+ and gamma-Ga2O3:Mn2+ nanocrystals was fabricated based on a strategy of "dopant isolation". X-ray diffraction and transmission electron microscopy indicated two nanophases, i.e. beta-YF3 and gamma-Ga2O3, embedded in the glass matrix. Analyses on the crystal structure, photoluminescence spectra, time-resolved emission spectra, and decay curves revealed the incorporation of Mn2+ ions into the tetrahedral sites of gamma-Ga2O3, while the absorption spectrum and Judd-Ofelt calculations demonstrated the selective doping of Tm3+ ions in the nine-fold coordinated sites of beta-YF3. Evidently, energy transfer between Tm3+ and Mn2+ is suppressed due to their spatial separation, which enables the tuning of the emissive color from blue, green, yellow and red to white by varying the dopant species and concentrations in the material. Such a strategy would provide a convenient route to integrate separate single-color-emitting components into unity for near-UV excited white-light LEDs and great opportunities for fabricating various nanophase embedded glass ceramics doped with distinct active ions.