Effects of Eu³⁺Sites on Photoluminescence in Ba₂Ln(BO₃)₂Cl (Ln = Gd, Y) Hosts

A series of Eu3+ ions doped Ba2Ln(BO3)2Cl (Ln = Gd, Y) orange-red emitting phosphors were prepared by solid state reaction method. The structure and optical properties were characterized by the X-ray diffraction and photoluminescence spectra. The samples could be excited efficiently by charge transfer band (CTB) centered at 254 nm and n-UV light (350–410 nm) from the 4f6 electron configuration transition. The orange-red emission peaked at 593 nm from the magnetic dipole transition dominates the emission spectra. Crystallographic sites of Eu3+ ions, the structure defect and charge compensation mechanism were discussed. The spectra properties were investigated according to the symmetry of crystallography of Eu3+ ion occupancy. The electric dipole transitions become stronger with the increase of Eu3+ ions concentration, and the optimal compositions of the Ba2Ln(BO3)2Cl:Eu3+ (Ln = Gd, Y) phosphors were also determined.