Improving luminescent property of SrIn₂O₄:Eu³⁺ by codoped A⁺ (A = Li, Na, K) or Sm³⁺

A series of SrIn₂O₄:Eu³⁺ phosphors are synthesized by a high temperature solid-state method, and their luminescent properties are investigated. They can be excited by 395-nm radiation, and produce red emission (619 nm); however, they have a low absorption of near-ultraviolet light with the wavelength of 400 nm-405 nm. When co-doped with A⁺ (A=Li, Na, K), the emission intensity of SrIn₂O₄:Eu³⁺ is significantly enhanced, but its emission and excitation spectral profile is unchanged. With codoping Sm³⁺, not only is the emission intensity of SrIn₂O₄:Eu³⁺ enhanced, but also the absorption is broadened and strengthened in the range of 400 nm-405 nm. The effect of Sm³⁺-doped content on the emission intensity of SrIn₂O₄:Eu³⁺, Sm³⁺ is investigated, and the optimal Sm³⁺ content is 0.02 mol.