Probing the optical properties and luminescence mechanism of a UV-emitting SrBPO 5 :Ce 3+ phosphor

Ce-doped (1 × 10 to 3.0 mol%) SrBPO phosphors were synthesized using a conventional solid-state reaction route at 1273 K in an air atmosphere. Phase and morphology of the samples were studied from powder X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) micrographs, respectively. The band gap energies of the pure and Ce-doped SrBPO phosphors were calculated from the recorded diffuse reflectance spectra. Photoluminescence (PL) and Ce lifetime were recorded at 300 and 77 K. Photoluminescence lifetime measurements revealed two-lifetime values for Ce at both 300 K (17 and 36 nsec) and 77 K (12 and 30 nsec), suggesting the presence of two different environments around Ce . Time-resolved emission spectroscopy (TRES) studies confirmed the presence of Ce in two different environments. In addition, SrBPO :Ce exhibited intense UV emission, signifying its possible use as an efficient sensitizer for solid-state lighting applications. The effect of γ-irradiation on PL was also determined. Thermally stimulated luminescence (TSL) glow curves of the γ-irradiated phosphor, along with trap parameters, dose-response, and the possible TSL mechanism were also investigated. Positron annihilation lifetime spectroscopy was carried out to probe defects present in undoped and Ce-doped SrBPO .