Highly crystallized transparent luminescent glass ceramics containing dual-phase ZnGa2O4 spinel and α-Zn2SiO4 willemite nanocrystals

Crystallization kinetics and photoluminescence studies on SiO2‐ZnGa2O4:Cr3+ glass ceramics

“…The effective lifetimes were determined to be 14.03 and 10.72 ms for SZ‐T0 and SZ‐T2 glass ceramics, respectively. The obtained luminescence lifetimes are much larger than that of Cr 3+ in ZnGa 2 O 4 nanophosphors (5.88 ms) prepared by hydrothermal reaction followed by post heat‐treatment 41 and ZnGa 2 O 4 :Cr 3+ in melt‐quenching glass ceramics (3.49 ms), 24 suggesting lower concentration of defects in the ZnGa 2 O 4 nanocrystals in this study. Moreover, the Cr 3+ luminescence lifetime was found to be prolonged when 2 mol% TiO 2 nucleant was added, which may be due to the higher crystallinity of ZnGa 2 O 4 in the glass ceramics by the aid of TiO 2 as also evidenced by the XRD results.…”

“…Similar Zn 2 SiO 4 nanocrystal phase was also observed to be precipitated the SiO 2 -Ga 2 O 3 -ZnO-Na 2 O glass ceramic prepared by melt quenching method. 22,24 The mean size of the precipitated ZnGa 2 O 4 nanocrystals was estimated to be 6 nm according to the Scherrer equation. When the annealing temperature increased to 1000 • C, the Zn 2 SiO 4 diffraction peaks become more evident.…”

“…15,[18][19][20][21] On the other hand, Cr 3+ -doped gallate transparent glass ceramics have been explored by many researchers. [22][23][24][25] Castaing et al introduced Yb 3+ and Cr 3+ into the ZnGa 2 O 4 nanocrystals imbedded in a glassy matrix, persistent luminescence in NIR wavelength region from both Cr 3+ and Yb 3+ ions was realized. 26 High fraction of ZnGa 2 O 4 :Cr 3+ nanocrystals were crystallized from the parent glass prepared by the melt-quenching method and intense NIR-persistent luminescence was observed.…”

“…Such Cr 3+ ‐doped gallate nanocrystals are excellent candidate as optical storage media in bioimaging due to their background‐free luminescence and deep tissue penetration properties 15,18–21 . On the other hand, Cr 3+ ‐doped gallate transparent glass ceramics have been explored by many researchers 22–25 . Castaing et al.…”

“…introduced Yb 3+ and Cr 3+ into the ZnGa 2 O 4 nanocrystals imbedded in a glassy matrix, persistent luminescence in NIR wavelength region from both Cr 3+ and Yb 3+ ions was realized 26 . High fraction of ZnGa 2 O 4 :Cr 3+ nanocrystals were crystallized from the parent glass prepared by the melt‐quenching method and intense NIR‐persistent luminescence was observed 22,24 . Sol‐gel provides a low‐temperature way to prepare transparent glass or glass ceramics.…”