Ce^(3+)and Dy^(3+)co-doped oxyfluoride glasses and glass ceramics containing CeF3 nanocrystals are prepared in a reducing atmosphere.XRD measurements and the calculated lattice parameters suggest that Dy^(3+)ions are incorporated with precipitated CeF3 nanocrystals along with a rise in the Dy^(3+)concentration or an increase in the annealing temperature.The glass ceramics emit white light close to the CIE coordinates of(0.3,0.3),derived from a combination of Ce^(3+)and Dy^(3+)emission.The CIE chromaticity coordinates of the Ce^(3+)and Dya+codoped glass ceramics can be tuned by varying the ratio of Ce^(3+)/Dy^(3+),while the luminescence intensity can be enhanced by heat treatment above 620℃.
The Eu 2＋ /Tb 3＋ /Sm 3＋ co-doped oxyfluoride glass ceramics containing Ba2LaF7 nanocrystals are prepared in the reducing atmosphere.The X-ray difiraction results show that Eu 2＋ ,Tb 3＋ and Sm 3＋ ions are enriched into the precipitated Ba2LaF7 nanophase after the annealing process.It deduces efficient energy transfers from Eu 2＋ to Tb 3＋ and Sm 3＋ and intenses warm white luminescence of the glass ceramics. Comparing with the glass,the luminescence quantum yield of the glass ceramics is also enlarged by about 3 times.This demonstrates the potential white light-emitting diode application of the glass ceramics produced in this letter.
The Ce^3＋and Dy3＋ co-doped fluorosilicate glass and glass ceramics containing SrF2 or CeF3 nanocrystals were prepared under reducing atmosphere. The precipitated nano-crystalline phase shifted from cubic SrF2 to hexagonal CeF3 gradually with the heat treatment temperature increasing flom 620 to 680 ℃. The glass and glass ceramics emitted white light, deriving from a combination of the Ce3＋ blue and the Dy3＋ yellow light. The CIE coordinates could be tuned by adjusting the ratio of Ce3＋/Dy3＋ concentration. The luminescence could be enhanced significantly by annealing the samples at the temperatures lower than 640℃.
