An investigation on luminescence and energy transfer of Ce³⁺ and Tb³⁺ in Ca₃Y₂Si₃O₁₂ phosphors

The present investigation aims to demonstrate the potentiality of Ca ₃ Y₂Si₃O₁₂ doped with Ce ³⁺ and Tb³⁺ along with Tb³⁺ and Ce³⁺ co-doped phosphors, which are prepared by a sol-gel method. Photoluminescence (PL) spectra revealed a brighter and broader violet-blue emission from the Ce³⁺ [5d (²D) → ²F_5/2,7/2] and an intense sharp green emission (545 nm) from the Tb³⁺ ( ⁵D₄ →⁷F₅) doped phosphors. For Tb³⁺ and Ce³⁺ co-doped phosphors, a strong green emission (⁵D₄→⁷F₅) was observed upon excitation with a UV wavelength (242 nm). An energy transfer phenomenon from Ce³⁺ to Tb³⁺ was observed in these co-doped nanocrystalline phosphors. It was also observed that their PL intensity depends on the doping concentration of Ce³⁺, while the concentration of Tb³⁺ is fixed. The mechanism involved in the energy transfer between Ce3+ and Tb3+ was explained with an energy level diagram. For these phosphors, X-ray diffraction and transmission electron microscopy were carried out to understand their structural properties.