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1.
O. M. Bordun 《Journal of Applied Spectroscopy》1998,65(1):149-151
Luminescence spectra of thin films of PbWO4 and Bi2WO6 are invesigated. The Alentsev-Fock method is used to separate the spectra into elementary components. The emission bands
with maxima at 2.8 eV in PbWO4 and at 2.93 eV in Bi2WO6 luminescence spectra are interpreted as the emission of self-localized Frenkel excitons. The bands with maxima at 2.35 and
1.75 eV in PbWO4 and at 2.35 and 1.9 eV in Bi2WO6 are related to oxygen vacancies.
L’vov State University, 50, Dragomanov St., L'vov, 290005, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii, Vol.
65, No. 1, pp. 143–145, January–February, 1998. 相似文献
2.
In the present work we investigate the tunneling luminescence (TL) of Y2O3, Y2O3:Eu, and Sc2O3 ceramics. From an analysis of the decay kinetics of the TL it is established that the recombinational processes are described
by a model involving recombination with a complex interaction. In addition, using the method of partial light sums, we show
that in the ceramics investigated the mechanisms of TL are the same and the majority of radiation-induced defects in pairs
are removed to distances exceeding the radius of effective tunneling transitions with a time constant of 10–100 sec. In the
Y2O3:Eu ceramics the distances between defects decrease. TL occurs in pairs whose electron component is F-centers that are thermally
released at 176 K in the Y2O3 ceramics and 200 K in the Sc2O3 ceramics. The hole components of tunneling pairs are associated with centers that are thermally released at 110 and 122 K
in the Y2O3 ceramics and at 121 and 146 K in the Sc2O3 ceramics.
To whom correspondence should be addressed.
I. Franko Lvov State University, 50, Dragomanov Str., Lvov, 290005, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 66, No. 5, pp. 649–651, September–October, 1999. 相似文献
3.
4.
We have studied the photoexcitation and luminescence spectra of Bi2WO6, Y2WO6 and Y2WO6: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 Bi2WO6, 3.02 eV in the luminescence spectrum of Y2WO6, and 2.95 eV in the luminescence spectrum of Y2WO6: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 Bi2WO6, 2.25 eV and 1.75 eV in the spectrum of Y2WO6, and 2.35 eV and 1.85 eV in the spectrum of Y2WO6:Bi are connected with oxygen vacancies.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 5, pp. 688–691, September–October, 2007. 相似文献
5.
Luminescence spectra for isostructural Y2SiO5 and Y2GeO5 are investigated. The spectra are resolved into elementary components by the Alentsev—Fock method. Bands with maxima in regions
of 2.6, 2.3, and 2.05 eV in the spectra of Y2SiO5 luminescence and in regions of 2.55, 2.25, and 2.0 eV in the spectra of Y2GeO5 luminescence are considered as radiative recombination of excited associative donor-acceptor Y3+−O2− pairs. The indicated bands are related to certain distances between yttrium (the donor) and oxygen (the acceptor). A band
with a maximum of 2.95 eV in Y2SiO5 and 3.0 eV in Y2GeO5 occurs in recombination of electrons with holes trapped by an anionic sublattice.
I. Franko L’vov State University, 50, Dragomanov St., L’vov, 290005, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 65, No. 4, pp. 528–531, July–August, 1998. 相似文献
6.
An investigation is made of the luminescence spectra of Me2WO6 ceramics (Me=Y, Sc, Bi). The spectra were decomposed into elementary components by the Alentsev—Fock method. Radiation hands
with a maximum at 3.02 eV in the Y2WO6 luminescence spectrum, at 2.8 eV in the ScWO6 spectrum, and at 2.93 eV in the Bi2WO6 spectrum are assigned to the light emission of self-localized Frenkel excitons. The bands with maxima at 2.25 and 1.75 eV
in the Y2WO6 spectrum, at 2.36 and 1.9 eV in the Sc2WO6 spectrum, and at 2.35 and 1.9 eV in the Bi2WO6 spectrum are related to oxygen vacancies.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol 67, No. 2, pp. 273–275, March–April, 2000. 相似文献
7.
For an ensemble of different types of luminescence centers with overlapping absorption bands, with no restrictions on the
optical densities, we have obtained relations describing the luminescence excitation spectra for each type of center. We consider
transformations of the relations in some limiting cases. We suggest a procedure for using the equations obtained to determine
the characteristics of the luminescence centers. Some of these procedures have been experimentally implemented in study of
intrinsic radiation color centers in lithium fluoride crystals. We have determined the ratios of the luminescence quantum
yields for F2 and F3+ color centers, and we have observed that a major role is played by nonradiative transitions in deactivation of the first
excited singlet state of F3+ centers.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 365–371, May–June, 2008. 相似文献
8.
Photoluminescence and excitation spectra of the spinel-type MgGa2O4 with 0.5 mol. % Mn2+ ions and Eu3+ content from 0 to 8 mol. % have been investigated in this work at room temperature. Polycrystalline samples were synthesized via high-temperature solid-state reaction method. Photoluminescence spectra of all samples exhibit host emission presented by a broad “blue” band peaking ∼430 nm, which consists of at least three elementary bands that correspond to different host defects. Excitation of the host luminescence showed the broad band with a maximum at 360 nm. Characteristic bands of d–d transitions of Mn2+ ions and f–f transitions of Eu3+ ions together with charge-transfer bands (CTB) of these ions were also found on the excitation spectra. Mn2+ and Eu3+ co-doped samples emit in green and red spectral regions. Mn2+ ions are responsible for the green emission band at 505 nm (4Т1→6А1 transition). The studies of photoluminescence spectra of activated samples with different Eu3+ ions content show characteristic f–f luminesecence of Eu3+ ions. The maximum of Eu3+ emission was found at 618 nm (5D0→7F2) and optimal concentration of activator ions was around 4 mol. %. 相似文献
9.
O. M. Bordun 《Journal of Applied Spectroscopy》2002,69(1):67-71
The luminescence spectra of Y2O3:Bi and Sc2O3:Bi ceramics have been investigated. The spectra have been resolved into elementary components by the Alentsev–Fock method. It has been established that the luminescence is attributed to emission centers of three types, two of which are due to the replacement of Y3+ (or Sc3+) by Bi3+ at the nodes of the crystal lattice of Y2O3 (or Sc2O3) with the point symmetry C
2 and C
3i
. The emission center Bi3+ in the position C3i
leads to the appearance of blue luminescence with maxima at 3.03 eV for Y2O3:Bi and at 3.05 eV for Sc2O3:Bi; this luminescence is attributed to the transition 3
P
1–1
S
0. The emission center Bi3+ in the position C
2 initiates green luminescence (which is also related to the 3
P
1–1
S
0 transition in Bi3+) with a maximum in the region of 2.40 eV in Y2O3:Bi and in the region of 2.46 eV in Sc2O3:Bi. The red luminescence band with maxima at 1.85 eV in Y2O3:Bi and at 1.95 eV in Sc2O3:Bi is related to the presence of structural defects. 相似文献
10.
I. N. Kassandrov N. N. Mel'nik A. P. Okonechnikov 《Journal of Applied Spectroscopy》1999,66(6):1004-1008
By the methods of amplitude and time-resolved spectroscopies the mechanisms of luminescence of ZnS−Ag(Al) single crystals
differing in dislocation density are studied in pulse laser excitation. Experimental results are analyzed based on the theory
of donor—acceptor pairs and the theory of centers surrounded with defect clouds. The data obtained are in agreement with the
second theory.
Ural State Technical University, 19 Mir Str., Ekaterinburg, 620002, Russia. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 66, No. 6, pp. 857–860, November–December, 1999. 相似文献
11.
Brian E. Trice 《光谱学快报》2013,46(2):333-348
We report a laser spectroscopic investigation of saturation effects in the spectra and dynamics of Eu2O3. The saturation effects occur at high laser intensity and appear as dips in the center of the fluorescence excitation lines and as a shortening of the 5D0 excited‐state decay curve. The saturation effects are observed in nanoparticles, micrometer‐sized particles, and a fused crystal of monoclinic‐phase Eu2O3 and in micrometer‐sized particles of cubic‐phase Eu2O3. We attribute the mechanism of the nonlinear luminescence quenching to upconversion by energy transfer. 相似文献
12.
V. T. Gritsyna Yu. G. Kazarinov V. A. Kobyakov Sickafus 《Journal of Applied Spectroscopy》2004,71(3):395-399
The flareup of x-ray luminescence in spinel single crystals (MgAl2O4) depending on the time of x-ray irradiation and the decay of fluorescence depending on the time elapsed after the termination of irradiation have been investigated. These dependences were measured at different powers of the irradiation dose (power of the x-ray tube) and at different temperatures of the samples. The experimental results suggest the existence of large-size complexes of defects, which include antisite defects and impurity ions, the exchange of charge carriers between which during and after irradiation leads to luminescence of the impurity ions. Transfer of charge carriers between isolated elements of the pairs of antisite defects (not interacting with the impurity ions) leads to the formation of a competing channel of recombination luminescence in the UV region of the spectra. The decay of fluorescence attributable to transitions in the Mn2+ and Cr3+ ions depending on the time elapsed after the termination of x-ray irradiation points to the existence of various combinations of antisite defects in the surroundings of these ions. 相似文献
13.
F. Sh. Aidaev 《Journal of Applied Spectroscopy》2002,69(3):484-486
The luminescence and luminescence excitation spectra of GaS:Pr single crystals are investigated. It is shown that in the single crystals of gallium sulfide the luminescence centers can be at two positions. The symmetry of the environment and the structure of these centers are considered. 相似文献
14.
E. M. Shishonok 《Journal of Applied Spectroscopy》2007,74(2):272-277
Complex and multiband photoluminescence spectra for GB and HBN centers in single crystals of cubic boron nitride (cBN) were
recorded in the wavelength ranges 385–400 nm and 365–395 nm and the nature of these centers was studied. The use of models
involving resonance vibrations and strongly shifted configuration diagrams for the electronic ground state and excited state
made it possible to associate formation of the GB-1 center with the presence of tungsten impurity in cBN. It was established
that the HBN band in the 300–350 nm range of the cathodoluminescence spectra of cBN polycrystals, single crystals, and micropowders
is associated with luminescence centers present in microinclusions of graphite-like boron nitride (hBN). The nature of the
hBN band is tentatively interpreted within the model of recombination of donor and acceptor defects in hBN: respectively nitrogen
vacancies and carbon atoms in positions substituting for nitrogen.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 2, pp. 241–246, March–April, 2007. 相似文献
15.
The luminescence spectra of thin Bi2W2O9 films have been investigated. The spectra were separated into elementary components by the Alentsev–Fock method. The radiation band with a maximum at 2.43 eV in the luminescence spectrum of Bi2W2O9 has been assigned to the Frenkel autolocalized excitons. The luminescence bands with maxima at 2.10 and 1.90 eV have been assigned to the emission of the centers whose energy levels are located in the forbidden band. The luminescence of the Bi2W2O9 films is due to the emission of the WO6 complex. 相似文献
16.
O. M. Bordun I. I. Kukharskii V. V. Dmitruk Yu. B. Kotsan 《Journal of Applied Spectroscopy》2006,73(5):667-671
We have studied the luminescence spectra and luminescence excitation spectra of Pb2Bi6O11 and Sn2Bi6O11 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 Pb2Bi6O11 and Sn2Bi6O11 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 Pb2Bi6O11 and Sn2Bi6O11 is due to radiative processes in structural complexes containing a bismuth ion in a nearest-neighbor oxygen environment.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 5, pp. 597–600, September–October, 2006. 相似文献
17.
Heat-stimulated luminescence (HSL) of x-ray-irradiated Y2O3, Y2O3:Eu, and Sc2O3 ceramics samples is investigated. An analysis of the form of the elementary contours making the HSL curves shows that recombination
processes at the HSL peaks with maxima at 110, 122, 176, 185, 200, and 247 K in Y2O3. ceramics and with those at 121, 136, 200, 215, and 221 K in Sc2O3 are described in terms of linear kinetics. The spectral composition of the HSL of the ceramic obtained is studied. Some methods
are employed to determine the activation energies and frequency factors corresponding to the HSL peaks. It is established
that the recombination processes occurring upon release of the trapping sites in the Y2O3 and Sc2O3 ceramic samples are conditioned by diffusion-controlled tunneling recombination due to heat-stumulated migration of Vk-centers.
L'vov I. Franko State University, 50, Dragomanov St., L'vov, 290005, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 3, pp. 348–353, May–June, 1997. 相似文献
18.
Luminescence spectra and photoluminescence excitation spectra of Y2O3:Bi and Y3Al5O12:Bi thin films were investigated. Luminescence was stimulated by the emission from two types of centers that were associated
with the substitution of Bi3+ for Y3+ in sites of the crystal lattice of Y2O3 (Y3Al5O12) with point symmetries C2 and C3i (D2 and C3i). The emission of Bi3+ in the site with point symmetry C3i causes blue luminescence in both Y2O3:Bi and Y3Al5O12:Bi films with maxima at 3.03 eV and 3.15 eV, respectively, that is related to the 3P1-1S0 transition. The emission of Bi3+ in the site with point symmetry C2 gives green luminescence in Y2O3:Bi with the maximum at 2.40 eV that is also related to the 3P1-1S0 transition. The emission of Bi3+ in the site with point symmetry D2 leads to ultraviolet luminescence in Y3Al5O12:Bi with the maximum at 3.75 eV that corresponds to the 3P1-1S0 transition. The red luminescence band with the maximum at 1.85 eV in Y2O3:Bi is due to the presence of structural defects.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 2, pp. 202–207, March–April, 2008. 相似文献
19.
Abstract Luminescence in Hg2Cl2, crystals excited with UV light is investigated in the spectral region 0.8–2.25 eV. Measurements are performed on as-grown samples and on samples previously exposed to UV light at RT. Six emission bands are found which depend on the concentration of the photochemical entities produced by irradiation of the crystals at RT. It is concluded that infra-red (IR) luminescence of Hg2Cl2 originates from crystal defects. The observed emission bands are tentatively attributed to the emission of (HgCIxBr3?x)? and (HgClxBr4?x)2? complexes formed with residual Br impurities. Centres responsible for IR Hg2Cl2 emissions are excited: (i) via excitons of Hg2Cl2, (ii) via excited states of isolated Hg2Br2 molecules, and (iii) resonantly through the excitation bands of defect centres. 相似文献
20.
V. I. Pokatashkin V. V. Syt'ko A. N. Krasovskii D. S. Umreiko 《Journal of Applied Spectroscopy》2000,67(6):1004-1010
The characteristic features of the low-temperature (6 K) luminescence of Rb3UO2F5 crystals in resonant selective laser excitation within an inhomogeneously broadened contour of a phonon-free line have been investigated. The presence of a nonselective spectral migration of the electron-excitation energy over a subsystem of uranylfluoride complexes is established. The energy migration is due to the Raman scattering of crystal phonons and is associated with the interaction of the lower excited energy levels of the uranyl complex, which leads to a disturbance of adiabaticity. 相似文献