Color-tunable luminescence in Ce-, Dy-, and Eu-doped oxyfluoride aluminoborosilicate glasses

A series of Ce-, Dy-, and Eu doped oxyfluoride aluminoborosilicate glasses prepared by melt-quenching method are studied for light emitting diodes applications. These glasses are investigated via optical absorption, photoluminescence, X-ray diffraction, Fourier transform infrared spectra, Commission International de I'Eclairage (CIE) color coordinates, and correlated color temperatures (CCTs). We find that the emission bands of Ce3+ ions move to the longer wavelengths with increasing excitation wavelengths and the molar ratio of B2O3/SiO2, Al2O3/SiO2, and B2O3/Al2O3 in the glass compositions. The precipitation of CaF2 crystals in glass can also lead to the red shift of the emission of Ce3+. The energy transfer processes among Ce3+, Dy3+, Eu3+, and Eu2+ ions are also investigated. The influence of the variation of glass network structure on the luminescence of Ce/Dy/Eu codoped glasses is studied. The CIE color coordinates and CCTs could be effectively tuned by adjusting the glass matrix compositions and excitation wavelengths. Furthermore, the near-ideal white light emission (color coordinate x=0.32, y=0.31) from the Ce/Dy/Eu codoped glass under near ultraviolet (UV) light excitation is realized.