Spectral properties and thermoluminescence of codoped PbWO₄:(Mo,Y) and PbWO₄:(F,Y) crystals

Abstract

Lead tungstate, PbWO4 single crystals codoped with Mo6+/F– and Y3+ ions were grown using the modified Bridgman method. Optical transmission, X‐ray excited luminescence, photoluminescence, ultrashort pulsed X‐ray excited fluorescent lifetime and thermoluminescence have been investigated. Compared to pure PbWO4, the codoped PbWO4:(Mo,Y) and PbWO4:(F,Y) crystals exhibit improved transmittance in the short‐wavelength region. Luminescence and light‐yield measurements demonstrated that Mo6+/F– and Y3+ codoping could enhance the luminescence of PbWO4 and reduce slow decay components. Doped Mo6+ and F– ions in PbWO4 were tentatively considered to occupy W and O sites, while Y3+ ions codoped in PbWO4:Mo/F mostly occupy Pb sublattice sites. The second excitation peak at 335 nm, which is the second effective excitation for the enhanced blue‐green emission in as‐grown PbWO4:(Mo,Y) and PbWO4:(F,Y) crystals, should be related to MoO42– groups and O vacancies (VO). Thermoluminescence glow curve measurement between RT and 400 °C provides complementary information about trapping states and the effect of Y3+ ion codoping resulting in the reduction of stable and temporary hole centers. Further work is needed to explain the doping and energy‐transfer mechanism. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Photo- and thermally stimulated luminescence of non-stoichiometric undoped PbWO4crystals

“…One can notice that the PbWO 4 :50.5 m% PbO crystal is similar to the PbWO 4 Bridgman crystal studied in Refs. 19, 26. In the latter crystal, the annealing creates the isolated WO 3 ‐type V O (responsible for the TSL peak at ≈200 K) from V O clusters (responsible for the TSL peaks around 230 K).…”

“…There are new ideas about the coloration, i.e., radiation damage mechanism in PbWO 4 24. To further increase the light yield, the continued attention is paid to doubly doped PbWO 4 25, 26. It is also worth mentioning that another technologic ways of PbWO 4 preparation were tempted, namely in the nanocrystal 27, 28 and thin film 29 forms which can provide further insight in the optical and luminescence characteristics of PbWO 4 .…”

Influence of Mo/Sb Co-Doping on Scintillation Properties of PbWO₄Crystal

“…In the past decade years, M. obayashi, M. Nikl and Mao et al have investigated the effects of doping PWO with different ions on the light output and other scintillation properties, including single dopant, co-doping, and three dopants [3][4][5][6][7]. It has been found that Mo 6+ or Fion doping could increase LO of the PWO crystals to about 10% of the BGO crystal [5,7], but it simultaneously produces a red shift of the position of maximum X-ray luminescence and very slow components of decay. S. H. Wang et al [8] reported that doping Sb 3+ could improve LO and reduce slow decay components even though it was inadequate in improving crystal radiation hardness.…”