Photoluminescent properties of Ce3+ in compounds Ba2Ln(BO3)2Cl (Ln = Gd and Y)

Abstract

Ce³⁺-doped Ba₂Ln(BO₃)₂Cl (Ln = Gd, Y) phosphors were synthesized through a conventional high-temperature solid state method in CO atmosphere. Structural and spectroscopic characterizations of the samples have been performed by X-ray diffraction and photoluminescence spectra measurements. The phosphors can be efficiently excited by near ultraviolet (n-UV) light resulting in blue emission. The optimal Ce³⁺ dopant concentrations in both compounds were determined, and the concentration quenching mechanisms were also discussed. The photoluminescence excitation (PLE) and emission (PL) spectra, and decay curves at liquid helium temperature were measured to analyze the crystallographic occupancy sites of Ce³⁺ in the Ba₂Ln(BO₃)₂Cl (Ln = Gd, Y) hosts. The thermal stabilities of the phosphors Ba₂Ln(BO₃)₂Cl:Ce³⁺ (Ln = Gd, Y) were studied using the dependence of the luminescence intensities on temperature (300–500 K), and their luminescence quenching temperatures and thermal activation energies were also determined. The results indicate that the phosphor Ba₂Gd(BO₃)₂Cl:Ce³⁺ offers excellent optical properties as a potential blue-emitting phosphor candidate for n-UV LEDs, such as a higher thermal stability and a stronger luminescence intensity, than those of the phosphor Ba₂Y(BO₃)₂Cl:Ce³⁺.