Wydział Chemii

Anna Madej

M. E. Witkowski

Andrzej J. Wojtowicz

Eugeniusz Zych

2015

Journal of Luminescence

160

50-56

10.1016/j.jlumin.2014.10.059

Naukowa

Angielski

Artykuł

Undoped and Bi³⁺-doped lutetium oxytungstate (Lu₂WO₆) powder materials were prepared by a solid state reaction method at selected temperatures between 1000 and 1400 °C. The structural, radio- and photoluminescent properties of these materials were investigated. Upon Bi activation, red-shifts of both emission and excitation bands are observed. While a broad emission band characteristic of undoped Lu₂WO₆ and resulting from a charge transfer transition of the tungstate group WO₆ peaks at 450 nm, the Bi³⁺-activated Lu₂WO₆ shows a broad band emission peaking at about 510 nm. This emission can be related to the transition between excited and ground states of a deep Bi donor. The ground state of this donor corresponds to an electron-occupied Bi-level at about 0.45 eV above the top of the valence band. Both compositions generate bright radioluminescence upon X-ray excitation at low temperatures. For Lu₂WO₆:Bi the radioluminescence efficiency is roughly stable in the range between 10 and 250 K, while undoped Lu₂WO₆ suffers from moderate thermal quenching above 10 K. The fraction of total radioluminescence due to Bi contribution in Lu₂WO₆:Bi increases from 0.19 at 10 K to 0.53 at room temperature. A simple configuration coordinate diagram is introduced in order to illustrate and describe the charge carrier recombination and light generation mechanism in these materials.

Lu2WO6, Radioluminescence, Photoluminescence, Deep Bi donor

http://dx.doi.org/10.1016/j.jlumin.2014.10.059

http://www.elsevier.com