Judd-Ofelt analysis of Eu3+ and adjustable emission in Eu3+/Eu2+ co-doped sodium aluminosilicate glasses

Europium-doped sodium aluminosilicate glasses were synthesized by using the melt quenching technique. X-ray diffraction, photoluminescence spectra and luminescence decay of Eu3+ ions in glasses were investigated to estimate structural and optical properties of the prepared glasses. Phonon energies, Judd-Ofelt (JO) intensity parameters Omega(lambda) (lambda = 2, 4, 6) and radiative properties such as transition probability (A), radiative lifetime (tau), and branching ratio (beta(R)) of Eu3+ ions in the prepared glasses were determined and Eu3+ emission may be suggested for suitable laser applications because of its high value of beta(R) = 70.8%. The adjustable emission of Eu3+/Eu2+ from red light to blue light can be reached by heating the prepared glasses in H-2 gas with various temperature and heating time. The reduction process from Eu3+ to Eu2+ ions in the glasses increases and maximum of Eu2+ emission shifts to the long wavelength with the increasing of temperature and heating time, that indicated the increase of the crystal field of sodium aluminosilicate heated in H-2 gas.