Studies on the structural, thermal and luminescence properties of Sr_1−xZrSi₂O₇:xEu³⁺ phosphors for solid state lighting

This paper reports the synthesis, structural, thermal and luminescence properties of Sr_1−xZrSi₂O₇:xEu³⁺ (x = 0.01 ≤ x ≤ 0.05 mol) phosphors by solid-state reaction method in air. The optimal Eu³⁺ ion concentration in Sr_1−xZrSi₂O₇:xEu³⁺ phosphor is 0.04 mol. The monoclinic crystal structure with P21/c space group was confirmed by the powder X-ray diffractometry (PXRD) technique. Thermal behavior of the present phosphors was investigated which shows better characteristics. Under 396 nm excitation, Eu³⁺ ions activated Sr_1−xZrSi₂O₇ phosphors exhibited a strong red emission centered at 617 nm due to the f–f transition of ⁵D₀ → ⁷F₂ transition. The critical doping concentration of Eu³⁺ ion was x = 0.04 mol and the critical distance was determined as 19.1117 Å. The energy transfer among Eu³⁺ ions in Sr_1−xZrSi₂O₇ phosphors was found to be a dipole–dipole interaction. Consequently, optimal phosphor shows a thermal stability up to 420 K, superior to that in analogous reports. And the quantum efficiency of prepared Sr_1−xZrSi₂O₇:xEu³⁺ phosphor with 396 nm excitation was calculated to be nearly 72%. The photometric results indicate that the synthesized Orange-Red phosphor can be potentially applicable for solid-state lighting and display devices applications.