Energy transfer and luminescence properties of Eu 3+ /Tb 3+ activated Na 6 Ca(SO 4 ) 4 phosphors

In this study, a series of Na6Ca(SO4)4:Eu3+/Tb3+ phosphors was synthesized using the wet chemical approach. X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), Ultraviolet-visible diffuse reflectance spectroscopy (UV-DRS) and Photoluminescence (PL) were used to characterize the synthesized materials. Powder XRD verified their crystal structure and phase purity. The Kubelka-Munk function was used to study the optical properties of doped and codoped phosphor samples. Excitation peaks occurred at 395 and 467 nm, whereas PL emission spectra revealed emission bands at 616 nm for Eu3+ ions, corresponding to the 5D0→7F2 transition. The green emission peak for Tb3+ ions is 545 nm. Excitation bands at 353, 373, and 379 nm indicated their potential for optoelectronic devices. This analysis indicates an effective energy transfer between Tb3+ and Eu3+ ions inside the host lattice. Blue, yellow, and orange-red emissions were validated by photometric analysis using the CIE-1931 chromaticity diagram. The Na6Ca(SO4)4:Eu3+/Tb3+ phosphor may be adjusted to emit different hues of light, making it useful for solid-state lighting, notably blue LED chip systems.