<scp> <scp>Eu‐</scp> </scp> , <scp> <scp>Tb‐</scp> </scp> , and <scp> <scp>Dy</scp> </scp> ‐Doped Oxyfluoride Silicate Glasses for <scp>LED</scp> Applications

Abstract

Luminescence glass is a potential candidate for the light‐emitting diodes ( LED s) applications. Here, we study the structural and optical properties of the Eu ‐, Tb ‐, and Dy ‐doped oxyfluoride silicate glasses for LED s by means of X‐ray diffraction, photoluminescence spectra, Commission Internationale de L'Eclairage ( CIE ) chromaticity coordinates, and correlated color temperatures ( CCT s). The results show that the white light emission can be achieved in Eu / Tb / Dy codoped oxyfluoride silicate glasses under excitation by near‐ultraviolet light due to the simultaneous generation of blue, green, yellow, and red‐light wavelengths from Tb , Dy , and Eu ions. The optical performances can be tuned by varying the glass composition and excitation wavelength. Furthermore, we observed a remarkable emission spectral change for the Tb 3+ single‐doped oxyfluoride silicate glasses. The 5 D 3 emission of Tb 3+ can be suppressed by introducing B 2 O 3 into the glass. The conversion of Eu 3+ to Eu 2+ takes place in Eu single‐doped oxyfluoride aluminosilicate glasses. The creation of CaF 2 crystals enhances the conversion efficiency. In addition, energy transfers from Dy 3+ to Tb 3+ and Tb 3+ to Eu 3+ ions occurred in Eu / Tb / Dy codoped glasses, which can be confirmed by analyzing fluorescence spectra and energy level diagrams.