Host and defect-related photoluminescence of structurally disordered K3WO3F3 oxyfluoride crystals

5th International Congress on Energy Fluxes and Radiation Effects 2016

Kozlov, A.V.^1 ; Pustovarov, V.A.^1

Ural Federal University, Mira str. 19, Yekaterinburg

620002, Russia^1

关键词: Elastic collision;    Electronic transition;    Inter-band transition;    Low temperatures;    Luminescence band;    Self-trapped exciton;    Temperature dependence;    Time resolution;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/830/1/012127/pdf
DOI  :  10.1088/1742-6596/830/1/012127

来源: IOP

【 摘 要 】

Spectra of photoluminescence (PL) in the region of 1.5-5.5 eV, PL excitation spectra (3-22 eV), PL decay kinetics and PL temperature dependence were measured for single crystals and ceramics K3WO3F3as well as for ceramics K3WO3F3irradiated by fast electrons. Synchrotron radiation was used for low temperature PL experiments with time resolution. Single crystals are transparent in microwave, visible and near UV range, inter-band transition energy is Eg= 4.3 eV. In K3WO3F3, the wide band luminescence in the region of 2.5 eV with the Stokes shift of 1.5 eV with the microsecond decay kinetics is connected with luminescence of triplet self-trapped excitons (STE). This luminescence is formed by electronic transitions in [WO3F3] octahedron. Different distortion of KWOF crystal lattice is manifested in the change of the Stokes shift of the STE luminescence band. The 3.2 eV emission band in low-temperature PL spectrum with decay times of 1.8 ns and 11 ns corresponds to singlet STE luminescence. A new 2.9 eV emission band is discovered in low-temperature PL spectrum in the samples irradiated by fast electrons (E = 10 MeV, D = 160 kGy). This emission band is excited not through the intracenter mechanism but through the creation of excitons bound on the defects. It is suggested that it is F-like centers of anionic sublattice induced by the mechanism of elastic collision.