Effect of mixing process on the luminescent properties of SrAl₂O₄:Eu²⁺, Dy³⁺ long afterglow phosphors

A new mixing method was developed for solid-state reaction synthesis of SrAl₂O₄: Eu²⁺, Dy³⁺ long afterglow phosphors. The morphology and crystal structure of the phosphors were analyzed with scanning electron microscope (SEM) and X-ray diffractometer (XRD). The excitation and emission spectra of the long afterglow phosphors were measured, and the main emission band was around 514 nm. The decay time of the product was measured and compared with the phosphors prepared using dry-mixing method and wet-mixing method. It was found that the aggregates and impurities in the phosphors prepared using dry-mixing method and wet-mixing method impaired the luminescent properties. The phosphors synthesized using the new mixing method had high initial brightness and slow decay speed. This method is considered of great potential applications in industry.