Diffusing Mn⁴⁺ into Dy³⁺ Doped SrAl₂O₄ for Full-Color Tunable Emissions

Dy³⁺ and Mn⁴⁺ codoped SrAl₂O₄ (SrAl₂O₄:Dy³⁺,Mn⁴⁺) phosphors were obtained by diffusing Mn⁴⁺ ions into Dy³⁺-doped SrAl₂O₄ via the constant-source diffusion technique. The influences of diffusion temperature and diffusion time on the emissions of SrAl₂O₄:Dy³⁺,Mn⁴⁺ were investigated. It was found that: (i) efficient red emission peaking at 651 nm can be readily achieved for SrAl₂O₄:Dy³⁺ by simply diffusing Mn⁴⁺ into SrAl₂O₄:Dy³⁺ at 800 °C and above; (ii) the red emission of Mn⁴⁺ becomes dominant over the characteristic emissions of Dy³⁺ when the diffusion temperature is 900 °C or higher; and (iii) the intensity of the red emission of SrAl₂O₄:Dy³⁺,Mn⁴⁺ is far more sensitive to diffusion temperature than to diffusion time. Our results have demonstrated that full-color tunable emissions can be realized for SrAl₂O₄:Dy³⁺, Mn⁴⁺ by tuning the parameters of diffusion temperature and diffusion time, which opens up a space for realizing easy color control of Dy³⁺-doped inorganic materials.