|
“Ferroelectric phase transition in the whitlockite-type Ca9Fe(PO4)7, crystal structure of the paraelectric phase at 923 K”. Lazoryak BI, Morozov VA, Belik AA, Stefanovich SY, Grebenev VV, Leonidov IA, Mitberg EB, Davydov SA, Lebedev OI, Van Tendeloo G, Solid state sciences 6, 185 (2004). http://doi.org/10.1016/j.solidstatesciences.2003.12.007
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.811
Times cited: 41
DOI: 10.1016/j.solidstatesciences.2003.12.007
|
|
|
“Layered ordering of vacancies of lead iron phosphate Pb3Fe2(PO4)4”. Malakho AP, Morozov VA, Pokholok KV, Lazoryak BI, Van Tendeloo G, Solid state sciences 7, 397 (2005). http://doi.org/10.1016/j.solidstatesciences.2005.01.007
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.811
Times cited: 7
DOI: 10.1016/j.solidstatesciences.2005.01.007
|
|
|
“New molybdenum oxides Ag4M2Zr(MoO4)6 (M=Mg, Mn, Co, Zn) with a channel-like structure”. Khobrakova ET, Morozov VA, Khasanov SS, Tsyrenova GD, Khaikina EG, Lebedev OI, Van Tendeloo G, Lazoryak BI, Solid state sciences 7, 1397 (2005). http://doi.org/10.1016/j.solidstatesciences.2005.08.010
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 1.811
Times cited: 9
DOI: 10.1016/j.solidstatesciences.2005.08.010
|
|
|
“Positional and orientational disorder in a solid solution of Sr9-xNi1.5-x(PO4)7 (x=0.3)”. Belik A, Izumi F, Ikeda T, Morozov VA, Dilanian R, Torii S, Kopnin E, Lebedev OI, Van Tendeloo G, Lazoryak BI, Chemistry and materials 14, 4464 (2002). http://doi.org/10.1021/cm0206901
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 28
DOI: 10.1021/cm0206901
|
|
|
“Ferroelectric and ionic-conductive properties of nonlinear-optical vanadate, Ca9Bi(VO4)7”. Lazoryak BI, Baryshnikova OV, Stefanovich SY, Malakho AP, Morozov VA, Belik AA, Leonidov IA, Leonidova ON, Van Tendeloo G, Chemistry of materials 15, 3003 (2003). http://doi.org/10.1021/cm031043s
Abstract: Structural, chemical, and physical properties of whitlockite-type Ca9Bi(VO4)(7) were studied by X-ray powder diffraction (XRD), electron diffraction (ED), second-harmonic generation (SHG), thermogravimetry, differential scanning calorimetry, dielectric, and electrical-conductivity measurements. A new phase-transition of the ferroelectric type was found in Ca9Bi(VO4)(7) with a transition temperature, T-c of 1053 +/- 3 K. The polar phase, beta-Ca9Bi(VO4)(7), is stable below T-c down to at least 160 K. The centrosymmetric beta'-phase is stable above T-c up to 1273 +/- 5 K. Above 1273 K, it decomposes to give BiVO4 and whitlockite-type solid solutions of Ca9+1.5xBi1-x(VO4)(7). The beta<---->beta' phase transition is reversible and of second order. Electrical conductivity of beta'-Ca9Bi(VO4)(7) is rather high (sigma = 0.6 x 10(-3) S/cm at 1200 K) and obeys the Arrhenius law with an activation energy of 1.0 eV. Structure parameters of Ca9Bi(VO4)(7) are refined by the Rietveld method from XRD data measured at room temperature (space group R3c; Z = 6; a = 10.8992(1) Angstrom, c = 38.1192(4) Angstrom, and V = 3921.6(1) Angstrom(3); R-wp = 3.06% and R-p = 2.36%). Bi3+ ions together with Ca2+ ions are statistically distributed among the M1, M2, M3, and M5 sites. Ca9Bi(VO4)(7) has a SHG efficiency of about 140 times that of quartz. Through the powder SHG measurements, we estimated the nonlinear optical susceptibility, Digital, at about 6.1-7.2 pm/V. This value for Ca9Bi(VO4)(7) is comparable with that for known nonlinear optical materials such as LiNbO3 and LiTaO3.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 51
DOI: 10.1021/cm031043s
|
|
|
“K₅Eu(MoO₄)₄, red phosphor for solid state lighting applications, prepared by different techniques”. Posokhova SMM, Morozov VA, Deyneko DVV, Redkin BSS, Spassky DAA, Nagirnyi V, Belik AAA, Hadermann J, Pavlova ETT, Lazoryak BII, CrystEngComm 25, 835 (2023). http://doi.org/10.1039/D2CE01107G
Abstract: The influence of preparation techniques on the structure and luminescent properties of K5Eu(MoO4)(4) (KEMO) was investigated. KEMO phosphors were synthesized by three different techniques: solid state and sol-gel (sg) methods as well as the Czochralski (CZ) crystal growth technique. Laboratory powder X-ray diffraction (PXRD) studies revealed that all KEMO samples had a structure analogous to that of other high temperature alpha-K5R(MoO4)(4) palmierite-type phases (space group (SG) R3m). Contrary to laboratory PXRD data, electron diffraction revealed that the KEMO crystal grown by the CZ technique had a (3 + 1)D incommensurately modulated structure (super space group (SSG) C2/m(0 beta 0)00) with the modulation vector q = 0.689b*. A detailed analysis of electron diffraction patterns has shown formation of three twin domains rotated along the c axis of the R-subcell at 60 degrees with respect to each other. Synchrotron XRD patterns showed additional ultra-wide reflexes in addition to reflections of the R-subcell of the palmierite. However, the insufficient number of reflections, their low intensity and large width in the synchrotron X-ray diffraction patterns made it impossible to refine the structure as incommensurately modulated C2/m(0 beta 0)00. An average structure was refined in the C2/m space group with random distribution of K1 and Eu1 in [M1A(2)O(8)]-layers of the palmierite-type structure. The dependence of luminescent properties on utilized synthesis techniques was studied. The emission spectra of all samples exhibit intense red emission originating from the D-5(0) -> F-7(2) Eu3+ transition. The integrated intensity of the emission from the Eu3+ 5D0 term was found to be the highest in the crystal grown by the CZ technique. The quantum yield measured for KEMO crystals demonstrates a very high value of 66.5%. This fact confirms that KEMO crystals are exceptionally attractive for applications as a near-UV converting red phosphor for LEDs.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.1
DOI: 10.1039/D2CE01107G
|
|
|
“Crystal Structure and Luminescent Properties of R2-xEux(MoO4)(3) (R = Gd, Sm) Red Phosphors”. Morozov VA, Raskina MV, Lazoryak BI, Meert KW, Korthout K, Smet PF, Poelman D, Gauquelin N, Verbeeck J, Abakumov AM, Hadermann J;, Chemistry of materials 26, 7124 (2014). http://doi.org/10.1021/cm503720s
Abstract: The R-2(MoO4)(3) (R = rare earth elements) molybdates doped with Eu3+ cations are interesting red-emitting materials for display and solid-state lighting applications. The structure and luminescent properties of the R2-xEux(MoO4)(3) (R = Gd, Sm) solid solutions have been investigated as a function of chemical composition and preparation conditions. Monoclinic (alpha) and orthorhombic (beta') R2-xEux(MoO4)(3) (R = Gd, Sm; 0 <= x <= 2) modifications were prepared by solid-state reaction, and their structures were investigated using synchrotron powder X-ray diffraction and transmission electron microscopy. The pure orthorhombic beta'-phases could be synthesized only by quenching from high temperature to room temperature for Gd2-xEux(MoO4)(3) in the Eu3+-rich part (x > 1) and for all Sm2-xEux(MoO4)(3) solid solutions. The transformation from the alpha-phase to the beta'-phase results in a notable increase (similar to 24%) of the unit cell volume for all R2-xEux(MoO4)(3) (R = Sm, Gd) solid solutions. The luminescent properties of all R2-xEux(MoO4)(3) (R = Gd, Sm; 0 <= x <= 2) solid solutions were measured, and their optical properties were related to their structural properties. All R2-xEux(MoO4)(3) (R = Gd, Sm; 0 <= x <= 2) phosphors emit intense red light dominated by the D-5(0)-> F-7(2) transition at similar to 616 nm. However, a change in the multiplet splitting is observed when switching from the monoclinic to the orthorhombic structure, as a consequence of the change in coordination polyhedron of the luminescent ion from RO8 to RO7 for the alpha- and beta'-modification, respectively. The Gd2-xEux(MoO4)(3) solid solutions are the most efficient emitters in the range of 0 < x < 1.5, but their emission intensity is comparable to or even significantly lower than that of Sm2-xEux(MoO4)(3) for higher Eu3+ concentrations (1.5 <= x <= 1.75). Electron energy loss spectroscopy (EELS) measurements revealed the influence of the structure and element content on the number and positions of bands in the ultraviolet-visible-infrared regions of the EELS spectrum.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 24
DOI: 10.1021/cm503720s
|
|
|
“Influence of the structure on the properties of NaxEuy(MoO4)z red phosphors”. Morozov VA, Lazoryak BI, Shmurak SZ, Kiselev AP, Lebedev OI, Gauquelin N, Verbeeck J, Hadermann J, Van Tendeloo G, Chemistry of materials 26, 3238 (2014). http://doi.org/10.1021/cm500966g
Abstract: Scheelite related compounds (A',A '')(n)[(B',B '')O-4](m) with B', B '' = W and/or Mo are promising new materials for red phosphors in pc-WLEDs (phosphor-converted white-light-emitting-diode) and solid-state lasers. Cation substitution in CaMoO4 of Ca2+ by the combination of Na+ and Eu3+, with the creation of A cation vacancies, has been investigated as a factor for controlling the scheelite-type structure and the luminescent properties. Na5Eu(MoO4)(4) and NaxEu(2-x)/33+square(2-x)/3MoO4 (0.138 <= x <= 0.5) phases with a scheelite-type structure were synthesized by the solid state method; their structural characteristics were investigated using transmission electron microscopy. Contrary to powder synchrotron X-ray diffraction before, the study by electron diffraction and high resolution transmission electron microscopy in this paper revealed that Na0.286Eu0.571MoO4 has a (3 + 2)D incommensurately modulated structure and that (3 + 2)D incommensurately modulated domains are present in Na0.200Eu0.600MoO4. It also confirmed the (3 + 1)D incommensurately modulated character of Na(0.138)Eu(0.621)Mo04. The luminescent properties of all phases under near-ultraviolet (n-UV) light have been investigated. The excitation spectra of these phosphors show the strongest absorption at about 395 nm, which matches well with the commercially available n-UV-emitting GaN-based LED chip. The emission spectra indicate an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+, with local minima in the intensity at Na0.286Eu0.571MoO4 and Na0.200Eu0.600MoO4 for similar to 613 nm and similar to 616 nm bands. The phosphor Na5Eu(MoO4)(4) shows the brightest red light emission among the phosphors in the Na2MoO4-Eu2/3MoO4 system and the maximum luminescence intensity of Na5Eu(MoO4)(4) (lambda(ex) = 395 nm) in the D-5(0) -> F-7(2) transition region is close to that of the commercially used red phosphor YVO4:Eu3+ (lambda(ex) = 326 nm). Electron energy loss spectroscopy measurements revealed the influence of the structure and Na/Eu cation distribution on the number and positions of bands in the UV-optical-infrared regions of the EELS spectrum.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 53
DOI: 10.1021/cm500966g
|
|
|
“Luminescence Property Upgrading via the Structure and Cation Changing in AgxEu(2–x)/3WO4and AgxGd(2–x)/3–0.3Eu0.3WO4”. Morozov VA, Batuk D, Batuk M, Basovich OM, Khaikina EG, Deyneko DV, Lazoryak BI, Leonidov II, Abakumov AM, Hadermann J, Chemistry of materials 29, 8811 (2017). http://doi.org/10.1021/acs.chemmater.7b03155
Abstract: The creation and ordering of A-cation vacancies and the effect of cation substitutions in the scheelite-type framework are investigated as a factor for controlling the scheelite-type structure and luminescence properties. AgxEu3+(2−x)/3□(1−2x)/3WO4 and AgxGd(2−x)/3−0.3Eu3+0.3□(1−2x)/3WO4 (x = 0.5−0) scheelite-type phases were synthesized by a solid state method, and their structures were investigated using a combination of transmission electron microscopy techniques and powder synchrotron X-ray diffraction. Transmission electron microscopy also revealed the (3 + 1)D incommensurately modulated character of AgxEu3+(2−x)/3□(1−2x)/3WO4 (x = 0.286, 0.2) phases. The crystal structures of the scheelite-based AgxEu3+(2−x)/3□(1−2x)/3WO4 (x = 0.5, 0.286, 0.2) red phosphors have been refined from high resolution synchrotron powder X-ray diffraction data. The luminescence properties of all phases under near-ultraviolet (n-UV) light have been investigated. The excitation spectra of AgxEu3+(2−x)/3□(1−2x)/3WO4 (x = 0.5, 0.286,0.2) phosphors show the strongest absorption at 395 nm, which matches well with the commercially available n-UV-emitting GaN-based LED chip. The excitation spectra of the Eu2/3□1/3WO4 and Gd0.367Eu0.30□1/3WO4 phases exhibit the highest contribution of the charge transfer band at 250 nm and thus the most efficient energy transfer mechanism between the host and the luminescent ion as compared to direct excitation. The emission spectra of all samples indicate an intense red emission due to the 5D0 → 7F2 transition of Eu3+. Concentration dependence of the 5D0 → 7F2 emission for AgxEu(2−x)/3□(1−2x)/3WO4 samples differs from the same dependence for the earlier studied NaxEu3+(2−x)/3□(1−2x)/3MoO4 (0 ≤ x ≤ 0.5) phases. The intensity of the 5D0 → 7F2 emission is reduced almost 7 times with decreasing x from 0.5 to 0, but it practically does not change in the range from x = 0.286 to x = 0.200. The emission spectra of Gd-containing samples show a completely different trend as compared to only Eu-containing samples. The Eu3+ emission under excitation of Eu3+(5L6) level (λex = 395 nm) increases more than 2.5 times with the increasing Gd3+ concentration from 0.2 (x = 0.5) to 0.3 (x = 0.2) in the AgxGd(2−x)/3−0.3Eu3+0.3□(1−2x)/3WO4, after which it remains almost constant for higher Gd3+ concentrations.
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 7
DOI: 10.1021/acs.chemmater.7b03155
|
|
|
“New solid electrolyte Na9Al(MoO4)6 : structure and Na+ ion conductivity”. Savina AA, Morozov VA, Buzlukov AL, Arapova IY, Stefanovich SY, Baklanova YV, Denisova TA, Medvedeva NI, Bardet M, Hadermann J, Lazoryak BI, Khaikina EG, Chemistry of materials 29, 8901 (2017). http://doi.org/10.1021/ACS.CHEMMATER.7B03989
Abstract: <script type='text/javascript'>document.write(unpmarked('Solid electrolytes are important materials with a wide range of technological applications. This work reports the crystal structure and electrical properties of a new solid electrolyte Na9Al(MoO4)(6). The monoclinic Na9Al(MoO4)(6) consists of isolated polyhedral, [Al(MoO4)(6)](9-) clusters composed of a central AlO6 octahedron sharing vertices with six MoO4 tetrahedra to form a three-dimensional framework. The AlO6 octahedron also shares edges with one NalO(6) octahedron and two Na2O(6) octahedra. Na3-Na5 atoms are located in the framework cavities. The structure is related to that of sodium ion conductor II-Na3Fe2(AsO4)(3). High-temperature conductivity measurements revealed that the conductivity (sigma) of Na9Al(MoO4)(6) at 803 K equals 1.63 X 10(-2) S cm(-1). The temperature behavior of the Na-23 and Al-27 nuclear magnetic resonance spectra and the spin-lattice relaxation rates of the Na-23 nuclei indicate the presence of fast Na+ ion diffusion in the studied compound. At T\u003C490 K, diffusion occurs by means of Na+ ion jumps exclusively through the sublattice of Na3-Na5 positions, whereas Na1 and Na2 become involved in the diffusion processes (through chemical exchange with the Na3-Na5 sublattice) only at higher temperatures.'));
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 9.466
Times cited: 13
DOI: 10.1021/ACS.CHEMMATER.7B03989
|
|
|
“Antiferroelectric phase transition in Sr9In(PO4)7”. Stefanovich SY, Belik AA, Azuma M, Takano M, Baryshnikova OV, Morozov VA, Lazoryak BI, Lebedev OI, Van Tendeloo G, Physical review : B : condensed matter and materials physics 70, 172103 (2004). http://doi.org/10.1103/PhysRevB.70.172103
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 3.836
Times cited: 17
DOI: 10.1103/PhysRevB.70.172103
|
|
|
“High-temperature phase transition in the whitlockite-type phosphate Ca9In(PO4)7”. Morozov VA, Belik AA, Stefanovich SY, Grebenev VV, Lebedev OI, Van Tendeloo G, Lazoryak BI, Journal of solid state chemistry 165, 278 (2002). http://doi.org/10.1006/jssc.2001.9521
Abstract: The double phosphate Ca9In(PO4)(7) was obtained by solid-state reaction and was studied by room and high-temperature Xray powder diffraction, electron diffraction, high-resolution electron microscopy, second-harmonic generation (SHG) technique, differential scanning calorimetry, dielectric and conductivity measurements. The beta-Ca9In(PO4)(7) room-temperature phase is related to the mineral whitlockite and is similar to beta-Ca-3(PO4)(2). It has space group R (3) over barc, with unit cell parameters: a = 10.4008(1) Angstrom, c = 37.272(1) Angstrom, Z = 6. The structure was refined by the Rietveld method (R-wp = 4.69, R-I = 1.81). A reversible first-order beta <----> beta' phase transition of the ferroelectric type with T-c = 902 K is revealed by SHG, differential scanning calorimetry and dielectric measurements. The centrosymmetric beta'-Ca9In(PO4)(7) (973 K) has space group R (3) over barc, a = 10.4611(2) Angstrom, c = 37.874 (1) Angstrom (R-wp = 4.27, R-I = 4.11). Compared to the low-temperature beta-Ca9In(PO4)(7) structure, beta'-Ca9In(PO4)(7) can be described as an orientational disordering of the P1O(4) tetrahedra together with a calcium disordering on the M3 site. (C) 2002 Elsevier Science (USA).
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 57
DOI: 10.1006/jssc.2001.9521
|
|
|
“A new iron oxophosphate SrFe3(PO4)3O with chain-like structure”. Morozov VA, Pokholok KV, Lazoryak BI, Malakho AP, Lachgar A, Lebedev OI, Van Tendeloo G, Journal of solid state chemistry 170, 411 (2003). http://doi.org/10.1016/S0022-4596(02)00133-0
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 12
DOI: 10.1016/S0022-4596(02)00133-0
|
|
|
“Structures of three polymorphs of the complex oxide K5Yb(MoO4)4”. Morozov VA, Lazoryak BI, Lebedev OI, Amelinckx S, Van Tendeloo G, Journal of solid state chemistry 176, 76 (2003). http://doi.org/10.1016/S0022-4596(03)00350-5
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 8
DOI: 10.1016/S0022-4596(03)00350-5
|
|
|
“Ag1/8Pr5/8MoO4: an incommensurately modulated scheelite-type structure”. Morozov VA, Mironov AV, Lazoryak BI, Khaikina EG, Basovich OM, Rossell MD, Van Tendeloo G, Journal of solid state chemistry 179, 1183 (2006). http://doi.org/10.1016/j.jssc.2005.12.041
Keywords: A1 Journal article; Electron microscopy for materials research (EMAT)
Impact Factor: 2.299
Times cited: 35
DOI: 10.1016/j.jssc.2005.12.041
|
|
|
“A novel red Ca8.5Pb0.5Eu(PO4)7 phosphor for light emitting diodes application”. Deyneko DV, Morozov VA, Hadermann J, Savon AE, Spassky DA, Stefanovich SY, Belik AA, Lazoryak BI, Journal of alloys and compounds 647, 965 (2015). http://doi.org/10.1016/j.jallcom.2015.06.123
Abstract: Ca9-xPbxEu(PO4)(7) (0 <= x <= 1) solid solutions with a whitlockite-type (or beta-Ca-3(PO4)(2)-type) structure (sp.gr. R3c) were prepared by a standard solid-state method in air. Their luminescent properties under near-ultraviolet (n-UV) light were investigated. Excitation spectra of Ca9-xPbxEu(PO4)(7) showed the strongest absorption at about 395 nm, which matches well with commercially available n-UV-emitting GaN-based LED chips. Emission spectra indicated an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+, with a maximum in the intensity for Ca8.5Pb0.5Eu(PO4)(7). The emission intensity of Ca8.5Pb0.5Eu(PO4)(7) was about 1.8 times higher than that of a Ca9Eu(PO4)(7) phosphor. We suggest that the introduction of Pb2+ is an efficient approach to enhance luminescence properties of such phosphors. We clarified the influence of the Ca2+/Pb2+ substitution on intensities of three bands for the D-5(0) -> F-7(0) transition in excitation spectra of Ca9-xPbxEu(PO4)(7). In addition, we found a reversible first-order phase transition from R3c to R (3) over barc symmetry by second-harmonic generation in the range from 753 K (x = 1) to 846 K (x = 0). (C) 2015 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
Impact Factor: 3.133
Times cited: 18
DOI: 10.1016/j.jallcom.2015.06.123
|
|
|
“Antiferroelectric properties and site occupations ofR3+ cations in Ca8MgR(PO4)7 luminescent host materials”. Belik AA, Morozov VA, Deyneko DV, Savon AE, Baryshnikova OV, Zhukovskaya ES, Dorbakov NG, Katsuya Y, Tanaka M, Stefanovich SY, Hadermann J, Lazoryak BI, Journal of alloys and compounds 699, 928 (2017). http://doi.org/10.1016/J.JALLCOM.2016.12.288
Abstract: Ca8MgR(PO4)(7) = La, Pr, Nd, Sm-Lu, and Y) phosphates with a beta-Ca-3(PO4)(2) related structure were prepared by a standard solid-state method in air. Second-harmonic generation, differential scanning calorimetry, and dielectric measurements led to the conclusion that all Ca8MgR(PO4)(7) are centrosymmetric and go to another centrosymmetric phase in the course of a first-order antiferroelectric phase transition well above room temperature (RT). High-temperature electron diffraction showed that the symmetry changes from R (3) over barc to R (3) over barm during the phase transition. Structures of Ca8MgR(PO4)(7) at RT were refined by the Rietveld method in centrosymmetric space group R (3) over barc. Mg2+ cations occupy the M5 site; the occupancy of the M1 site by R3+ cations increases monotonically from 0.0389 for R = La to 0.1667 for R = Er-Lu, whereas the occupancy of the M3 site by R3+ cations decreases monotonically from 0.1278 for R = La to 0 for R = Er-Lu. In the case of R = Er-Lu, the M3 site is occupied only by Ca2+ cations. P1O(4) tetrahedra and cations at the M3 site are disordered in the R (3) over barc structure of Ca8MgEu(PO4)(7). Using synchrotron X-ray powder diffraction, we found that annealing conditions do not significantly affect the distribution of Ca2+ and Eu3+ cations between the structure positions of Ca8MgEu(PO4)(7). Luminescent properties of CasMgEu(PO4)(7) powder samples were investigated under near-ultraviolet (n-UV) light. Excitation spectra of CasMgEu(PO4)(7) show the strongest absorption at about 395 nm that matches with commercially available n-UV-emitting GaN-based LED chips. Emission spectra show an intense red emission due to the D-5(0) -> F-7(2) transition of Eu3+. (C) 2016 Elsevier B.V. All rights reserved.
Keywords: A1 Journal article; Engineering sciences. Technology; Electron microscopy for materials research (EMAT)
DOI: 10.1016/J.JALLCOM.2016.12.288
|
|