Strong broad green UV-excited photoluminescence in rare earth (RE = Ce, Eu, Dy, Er, Yb) doped barium zirconate

The wet synthesis hydrothermal method at 100 °C was used to elaborate barium zirconate (BaZrO₃) unpurified with 0.5 mol% of different rare earth ions (RE = Yb, Er, Dy, Eu, Ce). Morphological, structural and UV-photoluminescence properties depend on the substituted rare earth ionic radii. While the crystalline structure of RE doped BaZrO₃ remains as a cubic perovskite for all substituted RE ions, its band gap changes between 4.65 and 4.93 eV. Under 267 nm excitation the intrinsic green photoluminescence of the as synthesized BaZrO₃: RE samples is considerably improved by the substitution on RE ions. For 1000 °C annealed samples, under 267 nm, the photoluminescence is dominated by the intrinsic BZO emission. It is interesting to notice that Dy³⁺, Er³⁺ and Yb³⁺ doped samples present whitish emissions that might be useful for white light generation under 267 nm excitation. CIE color coordinates are reported for all samples.