Luminescence photoexcitation spectra of α-Bi 2 O 3 ceramics are investigated. Luminescence spectra were deconvoluted into fundamental components using the Alentsev-Fok method. It is established that the luminescence spectra of α-Bi 2 O 3 ceramics consist of three fundamental bands with maxima at 2.75, 2.40, and 1.97 eV. A comparison of the results with those from an investigation of luminescence of various modifications of bismuth oxide and bismuth germanates suggests that luminescence of these compounds is caused by radiation processes that occur in structural complexes that contain the bismuth ion in a nearest oxygen environment.

with maxima at 3.03 eV and 3.15 eV, respectively, that is related to the 3 P 1 -1 S 0 transition. The emission of Bi 3+ in the site with point symmetry C 2 gives green luminescence in Y 2 O 3 :Bi with the maximum at 2.40 eV that is also related to the 3 P 1 -1 S 0 transition. The emission of Bi 3+ in the site with point symmetry D 2 leads to ultraviolet luminescence in Y 3 Al 5 O 12 :Bi with the maximum at 3.75 eV that corresponds to the 3 P 1 -1 S 0 transition. The red luminescence band with the maximum at 1.85 eV in Y 2 O 3 :Bi is due to the presence of structural defects.Introduction. Luminophores based on yttrium oxide Y 2 O 3 and yttrium-aluminum garnet Y 3 Al 5 O 12 are promising materials for electronics and scintillation and laser technology [1,2]. Such luminophores activated by ions of rare-earth elements are especially common. Moreover, Y 2 O 3 and Y 3 Al 5 O 12 activated by another group of important activators, the so-called mercury-like ions, of which Bi 3+ is one, are poorly studied [3,4]. Thin films of such compounds can be used as scintillators in luminescent screens or mercury-free luminescent photomultiplier bulbs. The spectral properties of these materials have been well studied [3][4][5][6][7]. However, many questions of scientific interest have not been finally resolved. These concern establishing the nature of the luminescence centers and their interaction with processes occurring in the excited lattice. Therefore, the investigation of thin films of Y 2 O 3 and Y 3 Al 5 O 12 is timely and addressed herein.Experimental. Thin films of Y 2 O 3 :Bi and Y 3 Al 5 O 12 :Bi were prepared by separate vaporization in vacuo on a fused quartz substrate. Sputtered films were annealed in air at 900-950 o C for 3-4 h. The content of Bi 3+ activator was 0.5-1.0 mol %. X-ray diffraction showed a polycrystalline structure with primary orientation in planes (222), (400), and (440) for Y 2 O 3 :Bi films and (400), (420), and (521) for Y 3 Al 5 O 12 :Bi films.Luminescence excitation and photoluminescence (PL) spectra of thin films of Y 2 O 3 :Bi and Y 3 Al 5 O 12 :Bi and luminescence spectra upon x-ray and laser excitation of Y 2 O 3 :Bi films were investigated. The photoexcitation source was a DKsEl-1000 lamp with ZMR-3 monochromator; the x-ray excitation source, an URS-55A (Russia) unit with a copper anode (40 kV, 2-12 mA). Luminescence upon laser excitation was studied using pulsed excitation by radiation from a LGI-21 laser (Ukraine) with λ ex = 337.1 nm. Emission of samples was analyzed using a SF-4A monochromator and recorded using an FÉU-51 (Russia) photomultiplier, the signal from which was fed through an amplifier into a PDA-1 recorder (Ukraine). An automatically regulated monochromator slit kept the number of quanta constant during the study of excitation spectra. A correction for the photodetector sensitivity was applied for luminescence spectra.Results and Discussion. Previous investigations of Y 2 O 3 :Bi ceramic [5][6][7] showed that the luminescence spectra contained at least two emission bands wi...

We have studied the photoexcitation and luminescence spectra of Bi 2 WO 6 , Y 2 WO 6 and Y 2 WO 6 :Bi ceramics. We used the Alentsev-Fock method to decompose the spectra into elementary components. The emission bands with maximum at 2.93 eV in the luminescence spectrum of Bi 2 WO 6 , 3.02 eV in the luminescence spectrum of Y 2 WO 6 , and 2.95 eV in the luminescence spectrum of Y 2 WO 6 :Bi are assigned to luminescence of self-localized Frenkel excitons. The bands with maxima at 2.35 eV and 1.90 eV in the spectrum of Bi 2 WO 6 , 2.25 eV and 1.75 eV in the spectrum of Y 2 WO 6 , and 2.35 eV and 1.85 eV in the spectrum of Y 2 WO 6 :Bi are connected with oxygen vacancies.Introduction. The problems of personal, industrial, and reactor dosimetry and also the use of nuclear physics methods in geophysics, medicine, and other fields of science and technology are responsible for the increasingly rigorous and diverse demands made on solid-state scintillators. Recently studies of tungstate compounds have become significantly widespread [1,2]. Tungstates are among a group of inorganic crystal phosphors whose luminescence is generally connected with excitation of elements of the crystal lattice itself. Among tungstate systems, some interest has been stimulated in oxytungstate compounds of lanthanides and also Y and Bi [3,4]. The spectral properties and kinetics of tungstates are considerably affected by defects which arise both in the crystal lattice and also as a consequence of deviation of the crystal composition from stoichiometric [1]. Taking into account the fact that the nature of the optically active centers determining the luminescent properties of these phosphors mainly remains unclear, study of oxytungstate systems in different states, such as single crystalline, ceramic, and thin-film states, seems rather important. The aim of this work was to study the luminescence of the ceramics Bi 2 WO 6 , Y 2 WO 6 , and Y 2 WO 6 :Bi.Experimental Procedure. Ceramic samples of the oxytungstates Bi 2 WO 6 , Y 2 WO 6 and Y 2 WO 6 :Bi were obtained by solid-phase synthesis, by annealing in air a premixed and pressed mixture of oxides of stoichiometric composition. The annealing temperature of 1000 o C-1100 o C corresponded to a temperature for the formation of Me 2 WO 6 (Me = Bi) in the oxide system Me 2 O 3 -WO 3 [5,6]. The content of the activator Bi 3+ in the starting material was 0.5 mole %. The x-ray excitation source was an URS-55 apparatus (Russia) with a copper anticathode (40 kW, 2-12 µA). The luminescence with laser excitation was studied in pulsed excitation mode using an LGI-21 laser with wavelength of the exciting light equal to 337.1 nm (3.68 eV). The photoexcitation source was a DksEl-1000 lamp with a ZMR-3 monochromator. Luminescence of the samples was analyzed using an SF-4A monochromator and detected by an FÉU-51 photomultiplier, the signal from which was fed through an amplifier to a PDA-1 recorder (Ukraine). The luminescence spectra were corrected for the spectral selectivity of the photodetector.Results and Disc...

We have studied the luminescence spectra and luminescence excitation spectra of Pb 2 Bi 6 O 11 and Sn 2 Bi 6 O 11 ceramics at 80 K. We have used the Alentsev-Fock to decompose the spectra into elementary components. We have established that the luminescence spectra of Pb 2 Bi 6 O 11 and Sn 2 Bi 6 O 11 ceramics contain three elementary bands each with maxima at 2.60, 2.32, 12.93 eV and 2.62, 2.30, 2.00 eV. Comparison of the data obtained with the results of a study of the luminescence spectra for a series of bismuth-containing oxide compounds suggest that luminescence of Pb 2 Bi 6 O 11 and Sn 2 Bi 6 O 11 is due to radiative processes in structural complexes containing a bismuth ion in a nearest-neighbor oxygen environment.