Spectral studies of Dy3+:zincphosphate glasses for white light source emission applications: A comparative study

Recently, much efforts have been focused on Dy3+-doped glasses due to their optical and luminescent properties for several applications such as display devices, white light emitting diodes, waveguides for optical telecommunication, etc. In the present study, the Dy3+-doped zinc phosphate (Dy3+:PZKAN (P2O5+ZnO+K2O+Al2O3+Na2O+Dy2O3)) glasses have been prepared by melt quenching technique and characterized through absorption (optical band gap, Urbach energies and Judd-Ofelt (JO) theory), photoluminescence (yellow (Y) to blue (B) luminescence intensity ratios (Y/B) and CIE color coordinates), decay time and quantum yield measurements. With the help of optical absorption, transition intensities and the well proposed JO theory, three phenomenological JO fitted parameters were estimated and in turn adopted to evaluate the required radiative parameters for specific excited luminescent levels of Dy(3+)ion. The luminescence transitions exhibit de-excitation (refers radiative-emission) levels in the optical region of 450-750 nm. Also while increasing Dy3+ ion content, the de-excitation intensities were quenched due to presence of higher content of Dy3+ ions. The fluorescence decay curve for all the glass samples have been recorded with 350 nm pumping and observed the de-excitation at 575 nm that belongs to the F-4(9/2)-> H-6(13/2) level. The CIE color coordinates were estimated with the help of CIE chromaticity diagram and the quantities were in close proximity of the optimised white light (towards yellow) region for all the glasses. The lifetime (952 mu s to 358 mu s) and quantum yield (67 to 11) values decreases with increasing concentration (Dy3+:0.05 mol % to 3.0 mol %). The present results have been compared and discussed with those of 72 reported Dy3+:glasses besides uniform labeling of glass compositions. From these results, it is concluded that the Dy3+:PZKAN glasses could also be useful for optical display devices and yellow laser applications.