On the photo and thermally stimulated luminescence properties of U doped SrBPO 5

Photoluminescence properties of U in SrBPO5 host: Effect of concentration and annealing temperature

“…The uneven shape of the particles observed in this case was due to the synthesis procedure. The spectra is similar to the data reported by Kumar et al [20] that showed a five band structure for the samples with peaks at 481 nm (20,790 cm À 1 ), 498 nm (20,080 cm À 1 ), 519 nm (19,268 cm À 1 ), 539 nm (18,518 cm À 1 ) and 560 nm (17,875 cm À 1 ). Another weak but prominent hump in the spectra was observable at 595 nm (16,806 cm À 1 ).…”

“…Recently Kumar et al have reported the stabilization of uranium as uranyl in one of the borophosphate based host i.e. SrBPO 5 (SBP) prepared through solid state reaction route [20]. However, the dopant ion concentration in the work was arbitrarily fixed at 1 mol%.…”

Revealing the oxidation number and local coordination of uranium in Nd 2 Zr 2 O 7 pyrochlore: A photoluminescence study

“…The efficient green emission around 535 nm observed in this case, suggests the absence of tetrahedral UO 4 2 À (red emission). The broad green emission band spectral profile (its symmetry around the 535 nm peak) seems to match better with the UO 6 6 À unit [12]. The origin of this emission is assigned to the parity forbidden charge transfer transition 5f-t 1u that is vibronically coupled by the ungerade vibrational modes of the UO 6 6 À octahedron.…”

“…in case of the silicate [3], pyrophosphate [11], borophosphate [12] and borate matrices [13], uranium gets stabilized as uranyl (UO 2 2 þ ), whereas, in case of the tetraborate [14] and zirconate [15] matrices, it was the octahedral uranate species, UO 6 6 À that gets stabilized preferentially. This difference is probably because of U-O bond length.…”

“…Depending upon the crystal filed of host lattice; uranium can stabilize in different forms of U(VI) in solids. Based on some of the recent work from our laboratory it was observed that uranium stabilizes as UO 2 2 þ in Sr 2 SiO 4 , SrBPO 5 , Sr 2 P 2 O 7 , ThO 2 , YBO 3 [3,[11][12][13][14] whereas as UO 6 6 À in SrZrO 3 , SrB 4 O 7 [15,16] etc.…”