Synthesis and luminescence of A3Bi(PO4)3:Eu2+ (A = Ba and Sr) powders

A 3 Bi(PO 4 ) 3 :Eu 2+ (A = Ba and Sr) powders were synthesized by solid sate reaction. The XRD patterns show that the obtained samples have the structural type of eulytine. The diffraction profile of Ba 3 Bi(PO 4 ) 3 :Eu 2+ samples shifts towards a lower 2θ angle because of the increase of cell volume. The excitation spectra of A 3 Bi(PO 4 ) 3 :Eu 2+ samples show the broad absorption originating from the transitions of the Eu 2+ ions. Under the UV excitation of 380 nm, the emission spectra of A 3 Bi(PO 4 ) 3 :Eu 2+ samples show broad emission band due to the electric-dipole allowed 4f–5d transitions of the Eu 2+ ions. There is a red-shift in the emission spectra when Sr 2+ ions are substituted with the larger Ba 2+ ions, which is caused by the variation of the crystal field and the increase of covalence. The corresponding luminescence decay times of A 3 Bi(PO 4 ) 3 :Eu 2+ samples fit well with a second-order exponential decay curve.