DEVELOPMENT OF HIGH COLOUR PURITY RED LIGHT EMITTING Sm DOPED Gd2Zr2O7 PHOSPHORS

Gd₂Zr₂O₇:Sm³⁺ phosphors with varying samarium concentrations (8–24 mol%) were successfully synthesized using a conventional solid-state reaction method. X-ray diffraction (XRD) confirmed the formation of a single-phase cubic pyrochlore structure, irrespective of Sm³⁺ doping levels, indicating successful incorporation of dopant ions into the host lattice. Photoluminescence (PL) studies revealed characteristic excitation peaks at 275 nm and 409 nm, and emission peaks at 614 nm and 624 nm, corresponding to Sm³⁺ electronic transitions. The optimal PL intensity was achieved at 12 mol% Sm³⁺, beyond which concentration quenching occurred, attributed to dipole-dipole interactions as supported by Dexter’s theory. FTIR analysis further validated the material's phase purity. Thermoluminescence (TL) studies on the 12 mol% sample exhibited glow peaks at 116 °C and 240 °C. The chromaticity coordinates (x = 0.6720, y = 0.3276) confirmed a high color purity (~99.9%) in the red emission region, indicating the phosphor’s strong potential for red-emitting optoelectronic applications.