Green Emission from Calcium Zirconium Silicate Doped with Trivalent Terbium Phosphor

Trivalent terbium ion (Tb³⁺)-doped calcium zirconium silicate (Ca₃ZrSi₂O₉) phosphors (Ca₃ZrSi₂O₉:xTb³⁺), with molar composition 0.005 ≤ x ≤ 0.13, were effectively produced by the standard sol–gel method. The synthesized samples were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform-infrared (FT-IR) spectroscopy, photoluminescence (PL) excitation and PL emission. XRD spectral profiles of the prepared samples demonstrate the formation of a monoclinic structure. SEM micrographs of the Ca₃ZrSi₂O₉:xTb³⁺ phosphor samples show chunky solids interlocked in a tile-like pattern. The FT-IR spectra reveal the structure and bond activities of the samples. The PL excitation spectra demonstrate the 4f⁸ → 4f⁷5d¹ transitions of Tb³⁺ ions under 545 nm emission wavelength. The PL emission spectra of Tb³⁺ ions recorded under 243-nm excitation wavelength exhibit ⁵D₃ → ⁷F_J (J = 6, 5, 4) and ⁵D₄ → ⁷F_J (J = 6, 5, 4, 3) transitions over the wavelength range of 350–650 nm. Of all these emission transitions, the one pertaining to the ⁵D₄ → ⁷F₅ transition around 545 nm is strong and attributed to green emission. The photometric analysis also confirms the green emission from the Ca₃ZrSi₂O₉:0.09Tb³⁺ phosphor, which further supports its potential application in the fabrication of LEDs and in solid state display applications.