Luminescence studies of zinc borates activated with different concentrations of Ce and La under x-ray and electron excitation

Several ZnB₂O₄ powder samples having dopants concentrations of 0.1, 0.01, 0.04 wt% Ce and La were prepared using the nitric acid method via the starting oxides. Several complementary methods such as powder X-ray diffraction (XRD), thermal analyses environmental scanning electron microscopy (ESEM), Radioluminescence (RL) and Cathodoluminescence (CL) techniques were used. Unique luminescence properties of Ce doped ZnB₂O₄ powder samples are reported for the first time. A new luminescence bands appearing in red part of the spectrum and having all the characteristics of Ce³⁺ were obtained from RL results. Changing the Ce and La concentration of 0.01–0.1 wt% leads to an increase in RL and CL intensities of Ce³⁺ and La³⁺ ions and also CL emission spectra of ZnB₂O₄ show gradual shift towards longer wavelength. When we compare the luminescence intensity of the samples it is seen that Ce doped ZnB₂O₄ has the highest intense whereas La doped ZnB₂O₄ has the lowest one. However, emission spectra of both Ce and La doped samples kept unchanged. - Highlights: • We present preparation of Zn(BO₂)₂:Ce³⁺, La³⁺ phosphors by a nitric acid method. • The luminescence properties were studied by different excitation sources for the first time. • The synthesis of Zn(BO₂)₂ doped with Ce³⁺ and La³⁺ can be prospective materials for display applications.