Mixed solvothermal synthesis and characterization of BaFBr:Eu ²⁺ nano/micro-crystals

Uniform BaFBr:Eu ²⁺ nano/micro-crystals with different morphology and size were prepared by solvothermal method in the ethanol-water mixed solvents. A possible formation process of the products was proposed on the basis of phase and morphology results under different reaction conditions. The phase structure, morphology and optical properties of the products were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), high-resolution TEM (HRTEM) and photoluminescence (PL). Preliminary results reveal that the phase, size and morphology of the products strongly depend on the reaction time, temperature and surfactant amounts. Annealing at 300°C under reducing atmosphere and excited at 280 nm UV-light, the BaFBr:Eu ²⁺ samples show sharp emission at 390 nm due to the transitions of 4f ⁶5d ¹ → 4f ⁷ of Eu ²⁺, which suggests the as-prepared BaFBr:Eu ²⁺ is a promising X-ray storage phosphor in imaging plates for computed radiography.