Synthesis, characterization and optical tuning of Sm3+ doped NaZnPO4 phosphors for white LED technology

This study presents a comprehensive investigation into the synthesis, structural-spectroscopic characterization, and optical properties analysis of Sm3-activated NaZnPO4 phosphors with varied Sm3+-doping percentiles, aimed at developing tunable luminescent materials for white-light-emitting diode (WLED) applications. The polycrystalline samples NaZn(1-x) Smx3+ PO4 (x = 0.00, 0.05, 0.10 and 0.15) phosphors were synthesized via a solid-state reaction method. X-ray diffraction data analysis confirms single phase monoclinic lattice with space group P 1 21/c 1 for all compositions. The Rietveld procedure also confirms the single phase and monoclinic structure of synthesized phosphors. Fourier-transform infrared) spectroscopy confirms compositional homogeneity. FE-SEM micrographs show irregularly stacked microstructures and morphology for all compositions irrespective of Sm3+ doping percentage. While EDS and Elemental mapping confirm uniform incorporation of Sm3+ ions in phosphors lattice. Diffuse Reflectance Spectra studies show Sm3+ doping resulted in redshift and band gap narrowing. In Photoluminescence spectroscopies, excitation and emission spectra reveal that distinctive photoluminescence spectra with notable emission peaks at 402 nm (6H5/2 → 4F5/2) and 599 nm (4G5/2 → 6H5/2). CIE chromaticity coordinates demonstrated varied color purity and coordinates for different doping levels, with promising orange-red emissions and increased luminosity. The observed optical properties suggest the potential suitability of Sm3+-activated NaZnPO4 phosphors as promising candidates for enhancing WLED efficiency and color quality.