Hydrothermal Synthesis and Luminescent Properties of BiPO4:Eu3+ Phosphors

In this study, BiPO₄:Eu³⁺ phosphors were synthesized by a facile hydrothermal route at different temperatures. The BiPO₄:Eu³⁺ particles were characterized by x-ray powder diffraction (XRD), infrared spectra, and luminescence spectroscopy. The XRD results reveal that the BiPO₄:Eu³⁺ particles present different phases for different hydrothermal temperatures. It is found that a hexagonal phase is formed at 100°C, which transforms to a low-temperature monoclinic phase (MP) when the hydrothermal temperature is increased to 150°C. This low-temperature MP transforms to high-temperature MP when the temperature is increased beyond 200°C. The luminescent properties of the BiPO₄:Eu³⁺ particles were studied using an excitation wavelength of 270 nm. The emission spectra display the bands associated with the ⁵D₀ → ⁷F _J (J = 1, 2, 3, and 4) electronic transitions of the Eu³⁺ cations. The intensity of the emission spectra increases with increasing hydrothermal temperature. These results demonstrate that BiPO₄:Eu³⁺ with different phases can be obtained through the hydrothermal method, which may enrich the solution chemistry for preparation of advanced materials with tailored functionality.