Structural and luminescence properties of Lead Free Dy3+ derived Sr2ZnWO6 yellow nanophosphor for w-LEDs

Dy 3+ -doped double perovskite Sr 2 ZnWO 6 nanophosphors were successfully synthesized via a hydrothermal route. X-ray diffraction analysis confirms the formation of a single-phase cubic structure with Fm 3̅ m space group, and Williamson-Hall analysis reveals the presence of compressive lattice strain in the doped system. FTIR spectra corroborate the characteristic vibrational modes associated with the Sr-O, Zn-O, and W-O bonds, confirming the phase formation. Field-emission scanning electron microscopy indicates agglomerated particles with a nearly uniform surface morphology. Optical band gap values were estimated using Tauc plots, assuming a direct band gap transition and observed to be in the range of ∼3.16 to 3.27 eV. Photoluminescence investigations demonstrate an intense yellow emission centered at 573 nm, attributed to the 4 F 9/2 → 6 H 13/2 transition of Dy 3+ ions, under both 295 nm and 355 nm excitations. Dy 3+ concentration-dependent studies reveal effective color tunability for 1, 3, and 5 at% doping levels. Notably, under 355 nm excitation, the 5at% Dy 3+ -doped Sr 2 ZnWO 6 sample exhibits optimal luminescence performance with a high color purity of ∼79% and a correlated color temperature (CCT) of ∼4840 K. Study reveals the multicolor wavelength tunability under UV excitation and near UV excitation generates the white light emission for light emitting diode application.