Synthesis and luminescence properties of Eu~(3+) and Sm~(3+) doped and co-doped BiPO_4 powders by a hydrothermal route

摘要

BiPO_4:Eu~(3+), BiPO_4:Sm~(3+), and BiPO_4:(Eu~(3+), Sm~(3+)) powders were synthesized by a hydrothermal route. The X-ray diffraction and Fourier-transform infrared spectroscopy results show that the samples are pure hexagonal phases. The excitation spectrum of BiPO_4:Eu~(3+) sample shows the characteristic absorption peaks of Eu~(3+) corresponding to the direct excitation from the ground state to the higher excited states of the europium f-electrons. The excitation spectrum of BiPO_4:Sm~(3+) sample consists of several narrow excitation lines due to the characteristic f-f transition of Sm~(3+). The emission spectrum of BiPO_4:Eu~(3+) specimen excited by 395 nm consists of lines mainly locating in the red area. The emission spectrum of BiPO_4:Sm~(3+) sample is composed of four emission bands, which are attributed to transitions from ~4G_(5/2) excited state to ~6H_(J/2) (J = 5, 7, 9, and 11) ground states of Sm~(3+). The excitation and emission spectra of BiPO_4:(Eu~(3+), Sm~(3+)) samples are different from single doped BiPO_4 samples. The introduction of Sm~(3+) can broaden and enhance the excitation intensity of Eu~(3+) and improve the emission dominance of Eu~(3+) at 617 nm.