Dy(3+)-doped zinc fluorophosphate glasses for white luminescence applications.

Dysprosium (Dy(3+)) ions doped zinc fluorophosphate (PKAZLFDy: P2O5-K2O-Al2O3-ZnF2-LiF-Dy2O3) glasses have been prepared and investigated their spectroscopic properties using absorption, emission and decay measurements. Judd-Ofelt analysis has been carried out to obtain the intensity parameters and in turn predicted radiative properties for the (4)F9/2 level of 1.0 mol% of Dy2O3 doped glass. Visible luminescence spectra have been obtained due to (4)F9/2→(6)HJ (J=11/2, 13/2, 15/2) transitions of Dy(3+) ions under 385 nm excitation. The yellow-to-blue luminescence intensity ratios and chromaticity coordinates of Dy(3+) ions in these glasses have been analyzed as a function of Dy(3+) ion concentration. The decay profiles for the (4)F9/2 level exhibit perfectly single exponential at lower concentrations (up to 1.0 mol%) and turn into non-exponential for higher concentrations (>1.0 mol%) due to energy transfer between donor (excited state Dy(3+) ion) and acceptor (ground state Dy(3+) ion). The results reveal that these glasses emit bright white light which is suitable for the development of W-LEDs.