Synthesis, characterization and optical properties of BaCeO3: Eu - An efficient red phosphor for w-LED applications

Abstract Single phase perovskite structured barium cerate (BaCeO 3 ) doped with europium phosphors were prepared through solution combustion route followed by calcination in air atmosphere. The morphology of the phosphor was analyzed from scanning electron micrograph. Diffuse reflectance spectra were recorded to determine the band gap energy of both undoped and Eu-doped BaCeO 3 using the Kubelka-Munk method. Eu 3+ exhibited intense red emission with high color purity and varied with Eu-concentration. The asymmetry ratio of Eu 3+ varied for different excitation wavelength and Eu-concentration. The environment around Eu 3+ was found to be more symmetric at 77 K unlike at 300 K. PL lifetime decay measurements of Eu 3+ luminescence revealed two different sites for it in this host. Time-resolved emission spectroscopy confirmed the presence of two different sites for Eu 3+ occupancy, exhibiting two different emission profiles. Thermally stimulated luminescence indicated multiple trap sites, and the intensity was linear with γ-dose in the range of 0–1000 Gy suggesting the possibility of using this material as a dosimetry phosphor. Positron annihilation lifetime spectroscopic studies indicated the presence of oxygen and barium vacancy-related defects.