Effect of pH on the microstructure and luminescence of Eu~(3+)-doped BiPO_4 phosphors

摘要

We focus on the effect of pH on the microstructure and luminescence of an Eu~(3+)-doped BiPO_4 phosphor, BiPO_4:0.05Eu~(3+). X-ray diffraction and field-emission scanning microscopy (FESEM) results show that as-prepared BiPO_4:0.05Eu~(3+) has a hexagonal rod with cones, and that its crystallinity decreases with increased pH. With increased pH, more OH~- ions exist and BiPO_4 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 BiPO_4:0.05Eu~(3+) samples display bands associated with ~5D_0 → ~7F_J electronic transition characteristics of Eu~(3+) 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 BiPO_4 phosphors for future research on device fabrication.