Red color Sr2NaMg2V3O12:Eu3+ phosphor with high thermal stability for w-LEDs

Sr2NaMg2V3O12:xEu phosphors with uniform particle size/morphology and good dispersion can be synthesized via solid state reaction. Under the optimum excitation wavelength of ∼340 nm, the Sr2NaMg2V3O12:xEu phosphor displays the broad emission band at ∼500 nm (blue-green emission, 3T1,2 → 1A1 transition of [VO4]3– and sharp emission peak at ∼610 nm (red emission, 5D0→7F2 transition of Eu3+), respectively. With the Eu3+ content increasing, the emission intensity of [VO4]3– decreases gradually while the emission intensity of Eu3+ increases, which is ascribed to the energy transfer from [VO4]3– to Eu3+ ions. The decay time of [VO4]3– (∼500 nm) increases gradually with the Eu3+ content increasing. The energy transfer efficiency and mechanism of [VO4]3–→Eu3+ ions were analyzed, respectively. The emission color of Sr2NaMg2V3O12:xEu phosphor was regulated from green to red via altering the Eu3+ ions concentration. It is delightful for us that the white color emission can be just achieved when the Eu3+ content is 5 at% (x = 0.05), and the w-LED can be assembled. By studying the luminescence temperature dependence and activation energy of Sr2NaMg2V3O12:xEu phosphor, it is shown that the phosphor has good thermal stability. The Sr2NaMg2V3O12:xEu powder is expected to be a new type of phosphor widely used in light and display areas.