Enhanced luminescence properties and morphology evolution of Bi_1−xPO₄:xDy³⁺by introducing excessive PO₄³⁻ions

A series of Dy³⁺ions doped bismuth phosphate (BiPO₄) phosphors have been successfully synthesized via a facile and simple hydrothermal method by tuning the molar ratio of PO₄³⁻/[Bi³⁺+Dy³⁺] and the Dy³⁺ions concentration, and the structure, morphology and luminescence properties of the phosphors were characterized by X-ray diffraction (XRD), field-emission scanning electronic microscopy (FE-SEM) and photoluminescence (PL) spectra. The XRD patterns indicate that the BiPO₄:Dy³⁺sample with low temperature monoclinic phase (LTMP) grows preferentially along the (120) crystalline plane at the excessive PO₄³⁻introduced. From the FE-SEM images, the morphology of BiPO₄:Dy³⁺powder varying from irregular polyhedron-like to rod-like is observed with increasing the molar ratio of PO₄³⁻/[Bi³⁺+Dy³⁺]. More importantly, the emission intensity of BiPO₄:Dy³⁺phosphor enhances dramatically with the excessive PO₄³⁻ions in the precursor. Therefore, the luminescence properties of the BiPO₄:Dy³⁺phosphors can be improved significantly through controlling the molar ratio of PO₄³⁻/[Bi³⁺+Dy³⁺] in the precursor mixture, which may be a novel way to explore new luminescent materials.