A new rare-earth phosphate compound Cs4PbTb2(PO3)12: Crystal structure and multicolor emitting properties introduced by Eu3+ doping

For the first time, rare-earth phosphate compound Cs 4 PbTb 2 (PO 3 ) 12 was prepared using molten salt method and structurally characterized by single-crystal X-ray diffraction (XRD). Its structure features a three-dimensional (3D) open framework constructed by P 4 O 12 cyclotetraphosphate groups and (Pb|Tb)O 8 polyhedra, with large holes filling with Cs + ions. The P 4 O 12 groups in this structure are isolated and each P 4 O 12 is surrounded by four (Pb|Tb)O 8 polyhedra by sharing terminal O atoms. Furthermore, the powder XRD , infrared (IR) spectrum, Ultraviolet–visible (UV–Vis) spectroscopy and photoluminescence (PL) properties for title compound were studied. Under near-UV excitation (378 nm), the emission colour turns from green through yellow to pure red by simply adjusting the Eu 3+ concentration due to the efficient Tb 3+ →Eu 3+ energy transfer mechanism.