Development and luminescent properties of Ce3+-doped KNaMg3Zn2-xSi12O30 blue-emitting phosphor via solid-state reaction method for white light-emitting diodes (WLEDs)

Abstract

A novel series of Ce³⁺-doped KNaMg₃Zn_2-xSi₁₂O₃₀ blue-emitting phosphors, with Ce³⁺ concentrations ranging from 1 to 11 mol%, was synthesized using the solid-state reaction method. Phase formation was confirmed by powder X-ray diffraction (XRD), and photoluminescence (PL) spectroscopy was employed to investigate the luminescent properties. Surface morphology was examined through scanning electron microscopy (SEM). The XRD patterns of the samples closely matched JCPDS card No. 48–0418, indicating successful phase formation. The optical characteristics of the synthesized phosphors were evaluated using emission and excitation spectra, along with decay curves. All the phosphors exhibited a strong blue emission at 441 nm, corresponding to the 5d-4f transition of Ce³⁺ ions. The PL emission spectra revealed an intense peak at 441 nm, resulting from electric dipole transitions upon excitation at 342 nm. The effect of Ce³⁺ concentration on photoluminescence intensity was also investigated, showing an increase in intensity with Ce³⁺ concentration up to 11 mol%, after which a decline was observed due to concentration quenching, attributed to dipole-dipole interactions. The optimized phosphor (11 mol% Ce³⁺), under 342 nm excitation, exhibited Commission Internationale de l'Éclairage (CIE) chromaticity coordinates, correlated color temperature (CCT), and color purity values of (0.1899, 0.1605) and 99.6 %, respectively. These results suggest that the Ce³⁺-doped KNaMg₃Zn_2-xSi₁₂O₃₀ phosphor is a promising candidate for blue phosphors in white light-emitting diode (WLED) applications.