Structural and photoluminescence properties of terbium (III) activated Li₂SiO₃ phosphors: an approach for bluish-green light emission

In this paper, a series of bluish-green emitting Li₂SiO₃:xTb³⁺(x = 0.01, 0.02, 0.03, 0.04 and 0.05 mol) phosphors were synthesized by solid state reaction method. The effects of Tb³⁺ doping concentration on photoluminescence (PL) properties of Li₂SiO₃:xTb³⁺ were investigated. Powder X-ray diffraction (PXRD) analysis show that the prepared phosphors confirm the sample has orthorhombic crystal structure. Energy dispersive X-ray analysis (EDX) shown that Tb element are uniformly doped in Li₂SiO₃ phosphor with a proper stoichiometric ratio. UV–Visible absorption spectroscopy was used to determine the band gap of Li₂SiO₃:0.04Tb³⁺ phosphor. The near ultraviolet light at the wavelength of 379 nm can excite this phosphor and exhibits blue emission at 484 nm at transition ⁵D₃ → ⁷F₆, and green emission at 541 nm at transition ⁵D₄ → ⁷F_5. The critical quenching concentration of Tb³⁺ in Li₂SiO₃host is 0.04 mol_. The life time measurements were also performed for Li₂SiO₃:0.04Tb³⁺ phosphor and estimated average life time. From the photometric properties result indicates that prepared phosphors were emit bluish-green light and they were useful for the solid state lighting applications.