Spectroscopic and photoluminescence characterization of Dy3+in Sr0.5Ca0.5TiO3phosphor

Influence of Dy3+ ion concentration on photoluminescence and energy transfer mechanism of promising KBaScSi3O9 phosphors for warm white LEDs

A novel white light emitting silicate-based phosphor of Dy³⁺ activated KBaScSi₃O₉ (xDyKBS) was prepared by a conventional solid state method. Powder X-ray diffraction patterns represent the pure phase of synthesized materials that was formed with monoclinic structure. The metal-ligand bonding nature and electronic band structure have been examined optical absorption spectra. The luminescence emission curves of the silicate phosphors display an intense yellow emission peak at 579 nm and a blue emission peak at 491 nm. Among the emission bands, the band observed in the yellow region due to ⁴F_9/2→⁶H_13/2 transition was found to be higher intensity. The radiative parameters like transition probabilities (A_R), branching ratios (β_R) and stimulated emission cross-section (σ_P^E) values were calculated using Judd-Ofelt parameters and refractive index values for the observed transitions in emission spectra. The life time measurements were made for ⁴F_9/2 → ⁶H_13/2 transition of all the studied samples by keeping an excitation at 350 nm and emission at 579 nm and decay curves were fitted to bi-exponential fitting method. The CCT values obtained from the color coordinates suggested that present xDyKBS phosphors can emit warm and neutral white light depending upon the dopant concentration under near-UV excitation. Our results demonstrated that the optimum concentration 0.05DyKBS phosphor can be successfully utilized as a promising and potential candidate for various innovative photonic applications like warm white LEDs, solar cells, optical sensors and lasers.