Synthesis and mechanoluminescent property of (Eu2+, Dy3+)-co-doped strontium aluminate phosphor by soft mechanochemistry-assisted solid-state method

(Eu²⁺, Dy³⁺)-co-doped strontium aluminate (SrAl₂O₄:Eu²⁺, Dy³⁺) powder as a mechanoluminescent (ML) phosphor was synthesized via soft mechanochemical pretreatment of precursor mixtures in a stirred media mill and subsequent calcination. Effect of soft mechanochemical pretreatment of precursors on the synthesis process as well as the photoluminescent (PL) and ML properties of SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor was investigated. The precursor mixtures unground and ground at different time and the resultant phosphors were characterized by laser particle size analysis, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy and optical property measurement. The results reveal that soft mechanochemical pretreatment of precursor mixture promotes the crystal growth, and reduces the subsequent calcination temperature. SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor can be obtained via calcining at 1200 °C for precursor mixture ground at 60 min, but formed via calcining at 1400 °C for unground precursor mixture. The phosphor synthesized with precursor mixture ground at 60 min has the maximum PL and ML intensities due to the enhancement of Eu²⁺ and Dy³⁺ ions into the crystal lattice to form more electron traps. The measurements by a designed ML instrument indicate that the ML intensity increases with increasing impact stress, and decreases with multiple applications of the same impact stress on phosphor disks.