Influence of compositional variation on optical and structural properties of Tb3+ and Dy3+ doped phosphosilicate glasses

The Tb3+ and Dy3+ doped phosphosilicate glasses prepared by melt quenching method are studied for light emitting diode applications. For certain base glass compositions, the crystals Ca3(PO4)2 and CaZn2(PO4)2 are precipitated during the melt quenching process, which induce the narrowness of the full width at half maximum (FWHM) of the emission bands peaked at 574 nm of Dy3+ ions. The intensity of emission bands of Tb3+ ions at 489 and 544 nm is significantly enhanced with the increase of P2O5 content. The ratio of the emission located at the yellow wavelength portion to that located at the blue wavelength region of the Dy3+ ions can be apparently tuned by changing the P2O5 content as well. In addition, the energy transfer between Tb3+ and Dy3+ in the as-prepared glasses is also discussed. The Commission International de I'Eclairage (CIE) chromaticity diagram shows that the emission hue is dependent on the glass composition. The Tb3+ and Dy3+ doped phosphosilicate glasses have promising prospects in light emitting diode applications.