Luminescence properties of BiPO4:Tb nanophosphors fabricated by facile chemical method

A facile chemical method was employed to prepare fine BiPO4:Tb3+ phosphor particles calcined at the same temperature. Introducing lithium greatly affected the morphology of the samples and further affected the luminescence intensity. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence (PL) spectroscopy. The XRD patterns of BiPO4:Tb3+ indicated a monoclinic phase. According to the fluorescence emission spectra, the most intense emission is the 5 D 4 → 7 F 5 transition peaking around 545 nm, corresponding to the green light. Based on the intensity ratios of 5 D 4 → 7 F 6 to 5 D 4 → 7 F 5 in the emission spectra, it can be concluded that introducing Li+ can change the symmetry of the crystal lattice and modify the emission intensity. Sharp lines at 377 nm are the strongest f–f transitions and match well with near-UV LED chips.