Synthesis and spectroscopic properties of Er3+-doped CaF2 nanocrystals in transparent oxyfluoride tellurite glass–ceramics

Transparent glass–ceramics in TeO2–SiO2–AlF3–CaO–NaF–ErF3 system were prepared. Effect of heat-treatment schedules on crystallization behavior and microstructure were analyzed by differential scanning caborimetry, X-ray diffraction, infrared spectrum and scanning electron microscopy. The sole CaF2 nanocrystal phase was confirmed, grains were spherical and distributed uniformly. Te and Si atoms existed in [TeO3] and [SiO4] forms. The full width at half maximum at 1533 nm emission increased from 39.16 nm to 43.37 nm after crystallization. Er3+ ions were incorporated into CaF2 nanocrystals with low phonon energies. The transmittance of glass–ceramics reached 78% at 780 nm and 90% at 1017 nm.

► Transparent oxyfluoride tellurite glass–ceramics were prepared successfully.
► CaF2 nanocrystals embedded homogeneously in residual glass matrix.
► FWHM at 1533 nm increased from 39.16 nm to 43.37 nm after crystallization.
► Er3+ ions were incorporated into CaF2 nanocrystals with low phonon energies.
► Transmittance reached 75% in visible light and 90% in infrared waveband.