Effect of pH on the microstructure and luminescence of Eu3+-doped BiPO4 phosphors

We focus on the effect of pH on the microstructure and luminescence of an Eu3+-doped BiPO4 phosphor, BiPO4:0.05Eu3+. X-ray diffraction and field-emission scanning microscopy (FESEM) results show that as-prepared BiPO4:0.05Eu3+ has a hexagonal rod with cones, and that its crystallinity decreases with increased pH. With increased pH, more OH− ions exist and BiPO4 cannot completely precipitate, which leads to increased irregular morphology. Afterwards, intensities of emission spectra decrease. The best excitation wavelength is 395 nm. Emission spectra of BiPO4:0.05Eu3+ samples display bands associated with 5D0 → 7FJ electronic transition characteristics of Eu3+ ions at different positions. Intensities of emission spectra decrease with increased pH. These results reveal the possibility of using pH adjustment to improve the luminescence of BiPO4 phosphors for future research on device fabrication.