Optical properties of Eu- and Dy-doped calcium aluminoborosilicate glasses for LED applications

Abstract

The Eu-/Dy-single and co-doped calcium aluminoborosilicate glasses for potential applications in light-emitting diodes are studied. We prepared these glasses using melt quenching method in ambient atmosphere and investigated their structural and optical properties by Fourier transform infrared spectra, absorption spectra, photoluminescence spectra, color coordinates, and correlated color temperatures (CCTs). The spontaneous conversion from Eu3+ to Eu2+ occurs in the as-prepared glasses. With increasing the content of B2O3 in Eu/Dy co-doped glasses, more Eu3+ ions are converted to Eu2+ ions and the emission color can be adjusted accordingly. Besides, the dependence of the spontaneous reduction of Eu3+ to Eu2+ on the Eu concentration is examined. We also find that the introduction of Dy3+ ions can affect the reduction extent from Eu3+ to Eu2+. Furthermore, the emission colors and CCTs of the Eu/Dy co-doped glasses can be modulated effectively by changing the glass compositions and the excitation wavelengths.