D. Spassky

D. Spassky
Lomonosov Moscow State University | MSU · Skobeltsyn Institute of Nuclear Physics

PhD

About

227
Publications
20,040
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
2,389
Citations
Introduction
The field of activity includes systematic study of luminescence and optical properties (emission and excitation spectra, decay kinetics, TSL, reflectivity) of a wide range of compounds based on complex oxides. The studies are aimed on the revealing of processes of energy transfer to the emission centers including the role of energy and spatial distribution of electronic excitations created by the absorption of the incident radiation in the formation of the luminescence yield and kinetics.
Additional affiliations
April 2001 - present
Lomonosov Moscow State University
Position
  • Researcher

Publications

Publications (227)
Article
Full-text available
Defects that are formed during crystal growth pose a serious obstacle for potential application of La3Ga5.5Ta0.5O14 (LGT) as a laser or piezoelectric crystal. We have performed the study of the defects origin in LGT crystals grown in different atmospheres using optical, EPR and time-resolved luminescence characterization methods. The absorption ban...
Article
Na3.6Lu1.8-x(PO4)3:xEu3+ phosphors were synthesized by a high-temperature solid-state reaction. A powder X-ray diffraction study revealed that homogeneous solid solutions with a NASICON-type structure were formed at 0 ≤ x ≤ 0.7. The Na3.6Lu1.8(PO4)3 structure was refined from the powder X-ray diffraction data and the cation distribution in the latt...
Article
This paper describes the influence of sintering conditions and Eu3+/Tb3+ content on the structure and luminescent properties of K5Eu1-xTbx(MoO4)4 (KETMO). KETMO samples were synthesized under two different heating and cooling conditions. A K5Tb(MoO4)4 (KTMO) colorless transparent single crystal was grown by the Czochralski technique. A continuous r...
Article
Sulfate anion plays an important role in the development of inorganic phosphors and is considered as the path for increasing the intensity of the luminescent properties. The heterovalent [PO4]3– → [SO4]2– anion substitution in the β-Ca3(PO4)2-type compounds was realized using the “ellestadite”-type strategy called by the analogy with the apatite-ty...
Article
The studies of structural, optical and luminescent properties of undoped Gd3AlxGa5-xO12 (x = 0,1,2,3) and Gd2YAl2Ga3O12 mixed crystals were carried out. Mixed crystals composition and lattice parameters were determined using EDX and XRD techniques. The distribution of cations between sites with different symmetry was obtained using Rietveld method....
Article
Phosphates of Ca8ZnLn(PO4)7 (Ln³⁺ = La – Nd, Sm – Lu) with β-Ca3(PO4)2-type structure were prepared by high-temperature solid-state technique on air. All compounds of Ca8ZnLn(PO4)7 are centrosymmetric and have R3¯c space group, which has been proved by several methods such as second-harmonic generation, dielectric spectroscopy, and Rietveld analysi...
Article
Full-text available
Abstract—(Pb,Gd)3(Al,Ga)5O12:Ce3+,Eu3+ films have been grown by liquid-phase epitaxy from a supercooled high-temperature solution based on the PbO–B2O3 system. We have measured and analyzed their absorption, photoluminescence, and photoluminescence excitation spectra. The results demonstrate that there is energy transfer from Ce3+ to Eu3+, resultin...
Article
Full-text available
A series of novel phosphates with the general formulas Ca9Gd0.9−xTm0.1Smx(PO4)7 and Ca9Gd0.9−yTmySm0.1(PO4)7 were synthesized by solid-state method. As-obtained phosphates were characterized by powder X-ray diffraction and second harmonic generation analyses, dielectric measurements, luminescence spectroscopy. All samples were single phase and char...
Article
A series of substituted vanadates of Ca9.75±δEu0.5(XO4)0.1(VO4)6.9 (X = W⁶⁺, Nb⁵⁺, Ge⁴⁺, Cr⁶⁺, P⁵⁺) with Ca3(VO4)2-type structure have been synthesized via a standard solid-state method. Powder X-ray diffraction (PXRD), photoluminescence excitation (PLE) and emission (PL) spectra were used to characterize the solid solutions. The successful substit...
Article
Luminescence properties of calcium and strontium molybdates, undoped as well as doped with Nd3+ ions were studied. The influence of temperature on the energy transfer processes from the intrinsic emission centers to activator is shown on the basis of the analysis of the temperature dependencies of luminescence spectra and decay kinetics. It is conc...
Article
Single-phase Na3.6Y1.8-x(PO4)3:xDy³⁺ phosphors were synthesized by high-temperature solid-state reaction. Powder X-ray diffraction study reveals that a homogeneous solid solution with a NASICON-type structure is formed at 0 ≤ x ≤ 0.4. Luminescence properties of the phosphors were studied using the methods of UV and VUV spectroscopy. Narrow emission...
Article
Full-text available
Ce-doped (Pb, Gd) 3 (Al, Ga) 5 O 12 and Ce-doped (Bi, Gd)3(Al, Ga) 5 O 12 single crystalline garnet films were grown using liquid-phase epitaxy method from supercooled PbO–B 2 O 3 - and Bi 2 O 3 –B 2 O 3 -based melt solutions on substrates from Gd 3 Ga 5 O 12 , Gd 3 (Al, Ga) 5 O 12 and Y 3 Ga 5 O 12 single crystals. Optical absorption, photo- and c...
Poster
Full-text available
The influence of temperature on the absorption, luminescence and excitation spectra was studied. Pronounced peaks related to intracenter electron transitions between ground 4f and excited 5d(1) and 5d(2) Ce3+ states were observed in these spectra in the crystal’s transparency region. Parameters of the absorption and emission bands related to Ce3+ a...
Poster
Here, we present the results of the study of structure and luminescence properties of NASICON-type phosphors Na3.6A1.8(PO4)3 (A = Y, Lu) doped with RE ions (Eu3+, Dy3+).
Conference Paper
Full-text available
Garnet crystals with cubic symmetry Gd3Al2Ga3O12:Ce (GAGG:Ce) are high potential scintillation crystals with remarkable properties [1]. Garnet structure contains 160 elements in unit cell and one of the specific types of defects in garnets is antisite defect [2], which significantly influence on their physical properties [2, 3]. The nature of the d...
Presentation
Full-text available
Garnet crystals with cubic symmetry Gd3Al2Ga3O12:Ce (GAGG:Ce) are high potential scintillation crystals with remarkable properties [1]. Garnet structure contains 160 elements in unit cell and one of the specific types of defects in garnets is antisite defect [2], which significantly influence on their physical properties [2, 3]. The nature of the d...
Article
Solid solutions of ScxY1-xVO4:Eu³⁺ were grown by solid state method and their structural and luminescent properties were studied using XRD, SEM and luminescence spectroscopy techniques. The influence of annealing on sample phase purity is investigated. A linear decrease of crystal lattice constants with the increase of x value is shown. The influen...
Article
A series of new Sr-based phosphors Sr8M²⁺Sm1-х(PO4)7:xEu³⁺, M = Mg²⁺, Zn²⁺ with β-Ca3(PO4)2-type structure were synthesized and studied. The Sr8MgEu(PO4)7 was obtained by three types of synthetic routs: high temperature solid-state, hydrothermal and sol-gel methods. The influence of synthesis routes and annealing conditions on luminescent propertie...
Article
Sub-nanosecond luminescence of Mn²⁺ in Mn-, Sn/Mn-, and Cu/Mn-doped Li2B4O7 ceramics is observed under laser excitation. Picosecond pulsed laser radiation (350–370 nm) generates the frequency-doubled radiation directly in a single microcrystal selected in a ceramic sample, with this secondary radiation falling within the impurity-induced VUV excita...
Article
The origin and thermal stability of charge trapping centers were studied in Li2MoO4 cryogenic scintillators by correlated electron paramagnetic resonance (EPR) and thermally stimulated luminescence (TSL) measurements. Up to five electron and three hole trapping centers were detected in the crystals X-ray irradiated at 77 K. The electron traps were...
Article
The series of β-Ca3(PO4)2-type phosphors Ca9.5-1.5xMgEu x (PO4)7 were synthesized by a solid-state route. Observation of the proper Eu3+ ion distribution in the Ca9.5Mg(PO4)7 host matrix was made by a direct method using 151Eu Mössbauer spectroscopy in combination with X-ray analysis and dielectric and luminescent spectroscopy. The photoluminescenc...
Article
The series of Tm-doped phosphates Ca9-xZnxLa0.9(PO4)7:0.1Tm³⁺ for phosphor-convertible white LEDs (pc-WLED) with β-Ca3(PO4)2-type structure were synthesized using a standard high temperature route. Intense blue emission in the visible spectrum was observed due to 4f-4f transitions in the Tm³⁺ ion. The phosphates have been characterized by powder X-...
Poster
Full-text available
Langasite-type crystals such as langasite La3Ga5SiO14 (LGS), langatate La3Ga5,5Ta0,5O14 (LGT) and catangasite Ca3TaGa3Si2O14 (CTGS) are characterised by calcium-gallogermanate (Ca3Ga2Ge4O14) structure (point group 32). These crystals are piezoelectric, not pyro- and ferroelectric, not hygroscopic, show no phase transitions up to the melting point a...
Poster
Full-text available
Garnets are well-known type of mixed crystal used as hosts for RE elements. Wide possibilities of isomorphic substitution of cations and introduced dopants made garnets very perspective for application as luminescent and scintillation material. One of the new functional materials of garnet type is Gd3Al2Ga3O12:Ce (GGAG:Ce). GAGG:Ce is characterized...
Article
The structural features of a series of ZnxMg1–xWO4 mixed crystals (x = 0, 0.26, 0.41, 0.68, or 1) have been investigated using X-ray diffraction analysis and Raman spectroscopy; the luminescence properties of the grown crystals have also been studied. The dependence of the unit-cell volume on the substitution-cation concentration x is determined. I...
Article
The temperature dependence of the fundamental absorption edge in molybdates CaMoO4, SrMoO4, PbMoO4, Pb2MoO5, and MgMoO4 has been studied. The dependences are approximated using the Urbach formula. Parameter E0 obtained as a result of the approximation is shown can be used to estimate the energy gap width in the molybdates.
Article
CdWO4:Sm single crystals were studied by optical, electron-paramagnetic and thermoluminescence spectroscopy in the temperature range of 4–750 K. A hopping diffusion of self-trapped excitons and energy transfer to Sm³⁺ centres is demonstrated. The mechanism of energy transfer includes the formation of a Sm³⁺ bound exciton either by direct excitation...
Article
Full-text available
The luminescence properties of ScxY1−xPO4:Eu3+ solid solutions have been studied under excitation by synchrotron radiation in the energy range of 4.5–50 eV. The luminescence originating from three different types of emission centers was observed, and the origin of the emission centers was determined. The light output of ScxY1−xPO4:Eu3+ was shown to...
Article
Full-text available
Се-doped (Pb,Gd)3(Al,Ga)5O12 single crystalline garnet films were grown using liquid-phase epitaxy method from supercooled PbO–B2O3-based melt solutions on substrates from Gd3Ga5O12 and Gd3Al2.26Ga2.74O12 single crystals. Optical absorption and photo- and cathodoluminescent properties of these epitaxial garnet films were studied. Се-doped (Pb,Gd)3(...
Article
A series of Ca8MTb1–xEux(PO4)7 (M = Mg²⁺, Zn²⁺, Ca²⁺; 0 ≤ x ≤ 1) with β-Ca3(PO4)2-type structure have been synthesized via a standard solid-state method. X-ray diffraction, second harmonic generation, photoluminescence emission and excitation spectra, and decay time curves were used to characterize solid solutions. The color coordinates of as-prepa...
Article
The influence of Sc cation substituent on structural and luminescence properties of GAGG:Ce crystals was studied. Unit cell parameters and space group were obtained using the XRD analysis. The chemical compositions of the crystals were determined using SEM-EDX and TEM-EDX techniques. Structures were refined by Rietveld method and the distribution o...
Article
Full-text available
Се-doped (Pb,Gd)3(Al,Ga)5O12 single crystalline garnet films were grown using liquid-phase epitaxy from four series of supercooled PbO–B2O3-based melt solutions on Gd3Ga5O12 and Gd3Al2.26Ga2.74O12 single crystal substrates. The optical and scintillation properties of the epitaxial garnet films were studied. The 5d-4f emission of Ce³⁺ ions within 45...
Article
Thin-film diamond-rare earth fluoride nanocomposites have been produced by chemical vapor deposition to be used as a source of intensive photo- and X-ray luminescence. The composites with embedded Eu containing nanoparticles show high-intensity orange narrow-band photoluminescence near the wavelength of 612 nm. Using β-NaGdF4: Eu instead of Eu(III)...
Article
Full-text available
Here we present the results of the study of fundamental absorption edge temperature dependence of CaMoO4, SrMoO4, PbMoO4, Pb2MoO5 and MgMoO4 molybdates. The dependencies were approximated using Urbach formula. It was shown that parameter E0 obtained from approximation can be used for the estimation of molybdates bandgap.
Article
Full-text available
This paper describes the influence of annealing temperature on the structure and luminescent properties of the KGd1−xEux(MoO4)2 (0≤x≤1). Compounds with the general formula (A’, A’’)n[(W, Mo)O4]m are investigated as luminescent materials for photonic applications, such as phosphor converted LEDs (light-emitting diodes). A KGd0.8Eu0.2(MoO4)2 light-ro...
Article
Charge carrier trapping was studied using EPR and TSL methods in ZnWO4, MgWO4 and mixed ZnxMg1-xWO4 crystals. An electron trapped at a perturbed W site was detected in MgWO4. It was also shown that holes are trapped at oxygen ions thus forming O−centers. Two different O− centers, one perturbed by a cation vacancy, another by Al impurity, were found...
Presentation
Full-text available
Here, we present the results of our study of the optical and photoluminescence properties of GAGG:Ce crystals irradiated by electron beam. All investigated samples were cut from crystals grown in JSC "Fomos-Materials" Co. using Czochralski method in Ir crucibles. The studies were performed on as-grown samples and on samples annealed in oxygen and v...
Conference Paper
Full-text available
Gd3Al2Ga3O12:Ce (GAGG:Се) are garnet crystals that are considered for application as scintillators. GAGG:Ce is characterized by short decay time (τ < 100 ns), high light yield (up to 50,000 ph/MeV), also its emission band corresponds to the sensitivity spectrum of conventional SiPMs. These properties allow application of GAGG:Ce in medical positron...
Cover Page
Full-text available
by Dina Deyneko et al. Luminescence of Eu 3+ as a probe for the determination of the local site symmetry in β-Ca 3 (PO 4) 2-related structures The symmetry breaking in the structures of β-Ca 3 (PO 4) 2 type compounds leads to signifi cant modifi cation of the properties. The work demonstrates a possibility of emission of Eu 3+ ions as a structural...
Article
Ca8CdEu(PO4)7 polycrystalline material with a β-Ca3(PO4)2-type (β-TCP) structure was obtained using a solid state technique. The structure was refined by Rietveld method using powder synchrotron X-ray diffraction data. The analysis of applying approaches confirmed that the Ca8CdEu(PO4)7 structure is similar to R3¯с structures of Ca8MEu(PO4)7 (M = M...
Article
Full-text available
Ca9–xMgxEu(PO4)7 solid solution with a β-Ca3(PO4)2-type (β-TCP) structure was obtained using a solid state technique studied by X-ray diffraction, luminescence and dielectric spectroscopy. The luminescent properties were measured, and the optical properties were related to the structural properties of the materials. The number of bands for the 5D0...
Article
Time-resolved luminescence of YAG-Ce (150 ppm) fiber crystal with Mg co-doping was studied under pulsed X-ray excitation and γ-rays (Cs 662 keV). The initial part of decay kinetics under X-ray excitation is faster than for direct cerium excitation (63 ns). Decay kinetics is also characterized by the presence of slow components with at least two cha...
Article
Novel red emitting phosphors Ca8MgSm1–х(PO4)7:xEu³⁺ with whitlockite-type structure were prepared by a high temperature solid-state reaction in air. Powder X-ray diffraction (PXRD), photoluminescence spectra, and fluorescence decay were used to characterize the structure and luminescence properties. All samples were found to have the expected rhomb...
Article
The optical and luminescence properties of La_3Ga_5SiO_14 lanthanum–gallium silicate crystals grown in atmospheres of argon and argon with the addition of oxygen are investigated. The results of calculations of the structure of energy bands are presented, obtained using the CASTEP module in the framework of the generalized gradient approximation an...
Article
Ag+ for Sm3+ substitution in the scheelite-type AgxSm(2-x)/3•(1-2x)/3WO4 tungstates has been investigated for its influence on the cation-vacancy ordering and luminescence properties. The x = 0.286, 0.2 scheelite-type phases were synthesized using a solid state method. Transmission electron microscopy revealed the (3+1)D incommensurately modulated...
Article
The luminescence properties of Y(NbxTa1-x)O4 mixed crystals were studied. Local structure modifications arise due to the inhomogeneous distribution of the substitutional ions in the mixed crystal and can be traced using the luminescence spectroscopy. In particular, it is shown that the intensity of exciton emission under interband VUV excitation in...
Article
Full-text available
Cathodoluminescence yield of hot intraband luminescence (IBL) under ∼100 keV pulsed electron excitation was evaluated in several halide and oxide compounds. Its values lie in the range of 5–35 ph/MeV, which is in accordance with the general assumptions on the mechanism of IBL. The expected inverse correlation between the IBL yield and highest phono...
Article
Ceramic samples of gadolinium tantalo-niobate mixed crystals were obtained by the solid-state technique. The dependence of luminescence properties on the Nb/Ta ratio in the Gd(Nb x Ta 1-x)O 4 system is studied in the 5e450 K temperature range, including thermostimulated luminescence curves in the series of solid solutions. The relation of nonlinear...
Article
Solid solutions LuxY1-xPO4 doped with Eu3+ were synthesized by the sol-gel method. Luminescence spectra under UV and X-ray excitation and luminescence excitation spectra in the UV-VUV energy range are presented. Observed variations of the structure of 4f-4f Eu3+ lines with the composition of the solid solution are explained by the fluctuations in t...
Article
This paper reports the luminescence properties of nanosized SrAl2O4:Eu2+ (1%) phosphors. The samples were prepared by combustion method at 600C, followed by annealing of the resultant combustion ash at 1000C in a reductive (Ar+H2) atmosphere. X-ray diffraction (XRD), photo luminescence (PL) and cathodoluminescence (CL) analysis and thermal stimulat...
Conference Paper
Full-text available
Molybdate single crystals are perspective for the cryogenic scintillating bolometers that operate in ultra-low temperature conditions and used for the registration of rare events. The article describes the favorable features and imperfections of molybdate cryogenic scintillators, the peculiarities of the crystal growth, the luminescence properties...
Article
Full-text available
The optical absorption and photoluminescence properties of cerium-activated (Pb,Gd)3(Al,Ga)5O12 epitaxial films are studied. The films are grown on single-crystal (111)-oriented Gd3Ga5O12 substrates by liquid-phase epitaxy from supercooled PbO – B2O3 melt solutions at different concentrations of gadolinium, cerium, and aluminium oxides in the charg...
Article
Mixed LuxY1-xVO4 crystals, undoped and doped with Eu3+, were synthetized by the solid state reaction method. The crystal structure and phase composition were controlled by the X-ray diffraction (XRD), Raman analysis, and scanning electron microscope (SEM) measurements. The samples' crystallinity was improved by annealing. Nevertheless, the lattice...
Article
Luminescent, optical and electronic properties of Na2Mo2O7 single crystals grown by two different procedures, the conventional Czochralski method and the low-temperature gradient Czochralski technique, are presented. The band structure calculations were performed in generalized gradient and local density approximations and allowed to determine the...
Article
La3Ga5.5Ta0.5O14 crystals were grown in pure argon and in an argon + 2% oxygen atmosphere. The growth atmosphere significantly effects the elemental composition of the crystals, their color, and the genesis and intensity of absorption bands in the ultraviolet, visible, and infrared spectral regions. Two types of defects were identified in the cryst...
Article
The Ca9Y(VO4)7-x(PO4)x (x=0, 1, 3, 4) solid solution whitlockite-like single crystals have been grown by the Czochralski method from mixtures of single phase Ca9Y(VO4)7 and Ca9Y(PO4)7 starting materials produced by solid-state synthesis. Real compositions of solid solution crystals has been determined and analyzed. It is found that crystals with x=...