Host-sensitized phosphorescence of Mn4+, Eu3+, and Yb3+ in MgAl2Si2O8

Mn4+ doped and Eu3+, Yb3+ co-doped MgAl2 Si2O8-based phosphors were prepared by conventional solid state reaction at 1,300 C. They were characterized by thermogravimetry, differential thermal analysis, X-ray powder diffraction, photoluminescence, and scanning electron microscopy. The luminescence mechanism of the phosphors, which showed broad red emission bands in the range of 600–715 nm and had a different maximum intensity when activated by UV illumination, was discussed. Such a red emission can be attributed to the intrinsic 2E + 4A2 transitions of Mn4+

Oxide ionic conductivity properties of binary δ-(Bi2O3)1 - x (Yb2O3) x system

In this study, after doping ytterbium oxide (Yb2O3) to a-bismuth trioxide (a-Bi2O3) in the range of 9% n 20% in a series of different mole ratios, heat treatment was performed by applying a cascade temperature rise in the range of 700–790 C for 48 hours and new phases were obtained in the (Bi2O3)1 x(Yb2O3)x system. After 24 hours of heat treatment at 700 C and 750 C and 48 hours of heat treatment at 790 C, mixtures containing 9–20 mol% Yb2O3 formed a face-centered cubic phase. With the help of X-ray diffraction (XRD), the crystal systems and lattice parameters of the solid solutions were obtained and their characterization was carried out. The surfaces of the solid solutions were detected by a scanning electron microscope (SEM). Thermal measurements were made by using a simultaneous DTA/TGA (differential thermal analysis/thermogravimetric analysis) system. The total conductivity (sT) in the d-Bi2O3 doped with Yb2O3 system was measured using the four-probe DC method

MgAl2Si2O8:Mn4+ systems doped with co-activator for optoelectronic applications

International Conference on Oxide Materials for Electronic Engineering - Fabrication, Properties and Applications, OMEE 2014 -- 26 May 2014 through 30 May 2014 -- -- 136309Mn4+ doped and Pr3+,4+, Sm3+, Gd3+, Tb3+,4+, Ho3+, Er3+, Tm3+ and Yb3+ co-doped MgAl2Si2O8-based phosphors were prepared by conventional solid state synthesis at 1300 ?. They were characterized by thermogravimetry (TG), differential thermal analysis (DTA), X-ray powder diffraction (XRD), photoluminescence (PL) and scanning electron microscopy (SEM). The luminescence mechanism of the phosphors, which showed broad red emission bands in the range of 600-715 nm and had a different maximum intensity when activated by UV illumination, was discussed. Such a red emission can be attributed to the intrinsic2E?4A2 transitions of Mn4+. © (2015) Trans Tech Publications, Switzerland

Comparison of MgAl2Si2O8:Mn4+ Systems Doped with Co-Activator Ions in Terms of Long Lifetime for Optoelectronic Applications

IEEE International Conference on Oxide Materials for Electronic Engineering - Fabrication, Properties and Applications (OMEE) -- MAY 26-30, 2014 -- Lviv Polytechn Natl Univ, Lviv, UKRAINEWOS:000363330400060Mn-4 doped and Pr-3+,Pr-4, Sm-3, Gd-3, Tb-3+,Tb-4, Ho3+, Er3+, Tm-3 and Yb3+ co-doped MgAl2Si2O8-based phosphors were prepared by conventional solid state synthesis at 1300 degrees C. They were characterized by thermogravimetry (TG), differential thermal analysis (DTA), X-ray powder diffraction (XRD), photoluminescence (PL) and scanning electron microscopy (SEM). The luminescence mechanism of the phosphors, which showed broad red emission bands in the range of 600-715 nm and had a different maximum intensity when activated by UV illumination, was discussed. Such a red emission can be attributed to the intrinsic E-2 ->(4)A(2) transitions of Mn-4.IEEE, Int Ctr Diffract Data, DEIS, IFPA, Minist Educ & Sci Ukrain

Novel red-emitting phosphors, (Mg(1-x-y)MnxDyy)Al2Si2O8 and (Mg(1-x-y)MnxTmy)Al2Si2O8

WOS:000339341300006Mn4+ doped and Dy3+, Tm3+ co-doped MgAl2Si2O8-based phosphors were prepared by conventional solid state reaction at 1,300 A degrees C. They were characterized by thermogravimetry, differential thermal analysis, X-ray powder diffraction, photoluminescence, and scanning electron microscopy. The luminescence mechanism of the phosphors, which showed broad red emission bands in the range of 600-715 nm and had a different maximum intensity when activated by UV illumination, was discussed. Such a red emission can be attributed to the E-2 -> (4)A(2) transitions of Mn4+.Erciyes University EUBAPErciyes University [FBD-09-804]This work was supported by Erciyes University EUBAP under project number FBD-09-804

Thermoluminescence properties of La3+, Gd3+, Dy3+ and Ho3+ co-doped MgAl2Si2O8:Mn4+

WOS:000453515900006PubMed:30302897Thermoluminescence properties of Mn4+-doped and La3+, Gd3+, Dy3+ and Ho3+ co-doped MgAl2Si2O8 host phosphors were investigated in detailed and reported for the first time. The phosphors were exposed to beta- Dand alpha-irradiation and the glow curves appeared at 260-262 +/- 2 degrees C and 245-252 +/- 2 degrees C, respectively. Thermoluminescence analysis show that the main glow peaks actually consisted of three distinct peaks (P-1, P-2 and P-3). In addition, all the phosphors had a main peak, and many satellite peaks also appeared up to 200 degrees C. Moreover, it was observed that La3+, Gd3+, Dy3+ and Ho3+ dopants in MgAl2Si2O8Mn4+ phosphor can change the thermoluminescence peak intensities, but they did not cause any new glow peak. In addition, when alpha-irradiation was used, the glow peaks were shift to a lower temperature region. Kinetic parameters of P-1, P-2 and P-3 were calculated, and it was found that P-1 and P-3 had first-order kinetics and P-2 had general-order kinetic parameters. In addition, it was found that when the easy and convenient annealing procedure was applied to the phosphorus, the thermoluminescence signal was measured as stable over many repetitions. The dose sensitivity, reproducibility and fading features of the powdered phosphors were investigated and computerized glow curve deconvolution analysis was also performed. Results showed that thermoluminescence properties of these materials were good but the fading reliabilities were poor and therefore the sintered or single crystal forms should be preferred for their better fading properties

Synthesis, characterization and oxide ionic conductivity of /3-type solid solution in bismuth oxide doped with ytterbium oxide binary system

In this study, after doping Yb203 substance to a-Bi203 substance in the range of 1% 3 system was measured using four-probe d.c. method

Fabrication of MgAl2Si2O8 : M-0.01 (M = Ni2+, Cu2+, Pd2+, Pt2+ and Ru3+): catalytic effects for the reduction of 2-or 4-nitroanilines in water

WOS:000363841700024Five new MgAl2Si2O8 : M-0.01 (M = Ni2+, Cu2+, Pd2+, Pt2+ and Ru3+) materials were developed for the reduction of nitroarenes as catalysts by conventional solid state reaction at 1300 degrees C. The prepared materials were characterized by thermal analysis, Fourier transform infrared spectroscopy, X-ray powder diffraction analysis, scanning electron microscopy, energy-dispersive X-ray analysis and nitrogen adsorption-desorption analysis. The catalytic activities of the prepared catalysts were tested in the reduction of 2- or 4-nitroanilines in aqueous media at ambient temperature in the presence of NaBH4 by UV-vis spectrophotometer. Furthermore, the MgAl2Si2O8 : M-0.01 catalysts can be recovered by filtration and reused for five cycles for the reduction of 2-nitroaniline. These results show that the MgAl2Si2O8 : M-0.01 catalysts can be used in practical applications in the reduction of nitroanilines.Erciyes University (ERUBAP)Erciyes UniversityWe acknowledge the financial support granted by Erciyes University (ERUBAP)

Nickel (II) complex [NiCl2(DMF)(2)L-2] bearing diaminobenzene and sulfonamide: Crystal structure and catalytic application in the reduction of nitrobenzenes

A new Bis[N-(2-aminophenyl)benzenesulfonamidej-di-chloro-Bis[O'-N,N-dimethyl-formamide]-nickel (II) complex [NiCl2(DMF)(2)L2] was synthesized in DMF solution in reflux media with NiCl2.2H(2)O and the pre-prepared N-(2-aminophenyl)benzenesulfonamide and the [NiCl2(DMF)(2)L-2] complex was crystallized in DMF/diethyl ether solution, for its single crystal. The complex characterized by FT-IR, elemental analysis, TG-DTA and UV Vis spectrophotometry methods, and its single crystal study were also performed by X-ray spectroscopy. Additionally, the catalytic efficiency of the fabricated [NiCl2(DMF)(2)L-2] complex was determined by UV Vis spectrophotometry in the reduction reaction of 2-nitroaniline (2-NA), 4-nitroaniline (4-NA) and nitrobenzene (NB) in presence of NaBH4 in water. The best conversion obtained as a result of the reduction of nitroarenes in the short time of 10 min. was 62.5 %, which was obtained at the 2-NA reduction. The conversion obtained from of the reduction of nitroarenes, are sequenced as 2-NA (62.5 %) > NB (56.5 %) > 4-NA (25.5%) in 10 min. In addition, the reaction products, both aqueous and short-term, are harmless to the environment, which will provide a significant reaction variety in terms of green chemistry. (C) 2019 Elsevier Ltd. All rights reserved