Synthesis and tunable luminescence properties of SrY2O4:Dy3+phosphors

Abstract

In this study, SrY2O4:Dy3+ phosphors were synthesized using the solid-state reaction method and evaluated after heat treatment at 1300 degrees C for 5 h. XRD analysis confirmed the orthorhombic structure of SrY2O4 with residual Y2O3 present. The addition of Dy3+ ions caused lattice expansion, impacting grain size and crystallinity. SEM images showed that the phosphor particles had irregular shapes with minimal size variation, although they tended to agglomerate due to high-temperature heat treatment. Optical analysis revealed significant absorption and emission peaks, with a strong excitation band in the 200-306 nm range and prominent sharp peaks in the 306-480 nm range, particularly at a 0.5 mol% doping concentration. Emission spectra indicated the highest intensity at 0.5 mol% Dy3+ concentration, with intensity decreasing due to concentration quenching at higher levels. Thermal stability tests showed peak emission intensity at 70 degrees C, with stability maintained up to 190 degrees C before notable thermal quenching. Chromaticity coordinates remained within the warm white region at both temperatures. This study provides detailed insights into the effects of Dy3+ doping on the structural, optical, and thermal properties of SrY2O4 phosphors. Compared to previous studies on rare-earth-doped SrY2O4 phosphors, this work is the first to systematically explore the substitution of Y3+ ions with Dy3+ ions until full replacement. The study not only confirmed that the highest emission intensity occurs at 0.5 mol% Dy3+ concentration, but also demonstrated that Dy3+-doped SrY2O4 phosphors exhibit excellent thermal stability, with emission stability maintained below 150 degrees C. These findings expand the potential applications of Dy3+-doped SrY2O4 phosphors, particularly in high-temperature environments and solid-state lighting.