Synthesis and Characterization of Eu ³⁺ ‐Doped Transparent Glass–ceramics Containing Nanocrystalline Sr ^II Nb ^IV O ₃

Abstract

The glass–ceramics containing a rarely achievable nanocrystalline Sr II Nb IV O 3 phase in the 53.75 SiO 2 –18.25 K 2 O –9 Bi 2 O 3 –9 SrO –9 Nb 2 O 5 –0.5 CeO 2 –0.5 Eu 2 O 3 (mol%) glass system were prepared by the melt‐quench technique followed by a two‐stage controlled heat treatment. The unusual oxidation state of Nb in Sr II Nb IV O 3 crystal is 4+ and upon heat treatment of the samples at lower temperature of 500°C for several hours, the glass composition and chemical environment around Nb ions played a key role for the formation of Sr II Nb IV O 3 in the glass–ceramics. The microstructure of the glass–ceramics was studied using TEM and FESEM . The TEM images advocate 10–40 nm crystallite size of Sr II Nb IV O 3 . FTIR study confirms that all the samples consist of SiO 4 , BiO 3 , BiO 6 , and NbO 6 structural units. The refractive index at different wavelengths was found to vary in the range 1.7105–1.7905 and increase with increase in heat‐treatment time. The luminescence spectra of Eu 3+ ‐doped glass and glass–ceramics were recorded at 465 nm excitation wavelength and the luminescence intensity is found to be increased with heat‐treatment time due to increase in crystallinity. The high intensity ratio of 5 D 0 → 7 F 2 to 5 D 0 → 7 F 1 indicates that the Eu 3+ ‐doped nanocrystalline Sr II Nb IV O 3 glass–ceramics are promising candidate materials as red‐light source.