Energy transfer engineering in matrix-sensitized NaBa10Y5W4O30: Sm3+ orange-red phosphors for solid-state lighting

Abstract

A sequence of matrix-sensitized NaBa₁₀Y₅W₄O₃₀: xSm³⁺ (x = 0.01–0.09) orange-red phosphors was successfully fabricated using a high-temperature solid-state reaction method. Their structural and luminescence properties were systematically characterized by XRD, SEM, photoluminescence spectroscopy, fluorescence lifetime measurements, temperature-dependent PL measurements, and CIE chromaticity coordinate analysis. XRD analysis verified the successful synthesis of phase-pure compounds, with the successful incorporation of Sm³⁺ ions causing no significant lattice distortion. SEM images combined with EDS mapping verified the homogeneous distribution of all constituent elements throughout the sample. Under 348 nm UV excitation, NaBa₁₀Y₅W₄O₃₀: Sm³⁺ phosphor exhibited its characteristic emission peak at 579 nm, corresponding to the ⁴G_5/2 → ⁶H_5/2 transition of Sm³⁺. The emission intensity attained its peak value at x = 0.05, beyond which concentration quenching occurred via electric dipole-dipole interactions among Sm³⁺ ions. This observation was accompanied by a gradual reduction in fluorescence lifetime as the Sm³⁺ ion concentration increased. Furthermore, CIE chromaticity coordinates remained steady in the orange-red light area, and variable-temperature spectra in the 298–423 K range demonstrated exceptional thermal stability. Warm-white light emission properties were confirmed by the CIE chromaticity coordinates of (0.3514, 0.3800) for the packed warm-white LED device. These results demonstrate that NaBa₁₀Y₅W₄O₃₀: Sm³⁺ orange-red phosphor possesses considerable promise for applications in white LED lighting.