SPECTROSCOPIC CHARACTERIZATION OF DY3++IONS DOPED PHOSPHATE GLASSES FOR EPOXY-FREE WHITE LED APPLICATIONS

Abstract

The present work illustrates a detailed spectroscopic analysis carried out on dysprosium ions doped Zinc Alumino Sodium Phosphate (ZnAlNaP) glasses with a chemical composition of (10-x) ZnO 20Al2O3-10Na2O-60P2O5- xDy2O3 (x = 0.1 to 2.0 mol%). The XRD spectrum recorded for an un doped ZnAlNaP glass demonstrates a broad hump confirming its non-crystalline nature. The FT-IR and Raman spectrum recorded for an un-doped ZnAlNaP and ZnAlNaPDy1.0 glass elucidates various functional groups and vibrational modes involved. The DSC & TGA studies conducted on an un-doped ZnAlNaP glass revealed its overall weight loss and thermal stability. The absorption spectra recorded were used to calculate the optical bandgap for the titled glasses and were found to be in the range from 4.52 to 4.81 eV. To understand the applicability of the titled glasses for epoxy-free solid-state lighting devices, photoluminescence (excitation, emission, and decay) spectra were recorded and analysed. The photoluminescence (PL) emission recorded under 350 nm excitation show two significant bands, 4F9/2 6H15/2 (blue) and 4F9/2 6H13/2 (yellow) at 484 nm and 573 nm respectively. Temperature-dependent PL studies conducted on 1.0 mol% of the Dy3+ ions in ZnAlNaP glasses revealed activation energy of 0.212 eV with a percentage of loss 25.6% in PL intensity. The CIE-chromaticity coordinates and color correlated temperature (CCT) were evaluated from the PL spectral characteristics. All the spectroscopic investigations conducted on the titled glasses finally reveal their superior nature in fabricating epoxy-free white light-emitting diodes and other related optoelectronic devices.