scholarly journals Synthesis and Luminescence Properties of ZrO2:Gd3+, RE3+(RE = Sm3+ ,Er3+) Phosphors

2018 ◽  
Vol 36 (2) ◽  
pp. 162-166 ◽  
Author(s):  
Esra Yildiz
Keyword(s):  
Electron Microscopy ◽  
Pechini Method ◽  
Photoluminescence Properties ◽  
Sem Images ◽  
Lifetime Measurements ◽  
X Ray ◽  
Thermal Gravimetry ◽  
Spherical Grains ◽  
Co Doped ◽  
Scanning Electron

Abstract In the present study, ZrO2co-doped with Gd3+/Sm3+and Gd3+/Er3+ions have been synthesized using Pechini method. Phase composition, morphology and photoluminescence properties of the synthesized phosphors were investigated by using X-ray powder diffraction (XRD), differential thermal analysis/thermal gravimetry (DTA/TG), scanning electron microscopy (SEM) and photoluminescence spectrofluorometer (PL). After heating at 1200 °C, XRD revealed that the phosphors were crystallized as monoclinic and tetragonal multiphases. SEM images indicated that the phosphors consist of fine and spherical grains with a size around 200 nm to 250 nm. Luminescence studies of these phosphors have been carried out on the emission and excitation, along with lifetime measurements

scholarly journals Photoluminescence properties of ZrO2:Gd3+, ZrO2:Gd3+ – Dy3+ and ZrO2:Gd3+ – Yb3+ phosphors by Pechini method

2018 ◽  
Vol 36 (1) ◽  
pp. 157-161
Author(s):  
Esra Yildiz
Keyword(s):  
Powder Diffraction ◽  
Optical Materials ◽  
Pechini Method ◽  
Photoluminescence Properties ◽  
Emission Analysis ◽  
Lifetime Measurements ◽  
X Ray ◽  
Thermal Gravimetry ◽  
Potential Applications ◽  
Scanning Electron

AbstractZr0.99Gd0.01O2, Zr0.98Gd0.01Dy0.01O2 and Zr0.98Gd0.01Yb0.1O2 phosphors were synthesized by Pechini method at 1200 °C for 12 h in air. The phosphors were characterized by using X-ray powder diffraction (XRD), differential thermal analysis/thermal gravimetry (DTA/TG), scanning electron microscopy (SEM) and photoluminescence spectrofluorometer (PL). X-ray powder diffraction studies showed that the phosphors were crystallized as monoclinic and tetragonal multiphases. The particle size of the phosphors after heat treatment at 1200 °C was found to be of 200 nm to 250 nm. Luminescence studies on these phosphors have been carried out on the emission and excitation, along with lifetime measurements. The results of emission analysis indicate that the phosphors are expected to find potential applications as new optical materials.

scholarly journals An XRD, SEM and TG study of a uranopilite from Australia

2006 ◽  
Vol 70 (3) ◽  
pp. 299-307 ◽  
Author(s):  
R.L. Frost ◽  
M.L. Weier ◽  
G.A. Ayoko ◽  
W. Martens ◽  
J. Čejka
Keyword(s):  
Electron Microscopy ◽  
Mass Spectrometry ◽  
Northern Territory ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Evolved Gas ◽  
X Ray ◽  
Temperature Range ◽  
Step Over ◽  
Scanning Electron

AbstractA uranopilite from The South Alligator River, Northern Territory, Australia, has been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) with EDAX attachment, and thermogravimetry in conjunction with evolved gas mass spectrometry. The XRD shows that the mineral is a pure uranopilite with few if any impurities. The SEM images show that the uranopilite consists of elongated crystals, up to 50μm long and 5 μm wide. Thermogravimetry combined with mass spectrometry shows that dehydration occurs at ∼31°C resulting in the formation of metauranopilite. The first dehydration step over 20–71°C corresponds to a decrease of 5.4 wt.%, equivalent to 6.076 H2O. The second dehydration step, over the temperature range 71 –162.4°C corresponds to a decrease of 4.7 wt.%, equivalent to 5.288 H2O, making a total of 11.364 moles of H2O, close to 12 H2O for uranopilite.Dehydroxylation takes place over the temperature range 80–160°C. The loss of sulphate occurs at higher temperatures in two steps at 622 and 636°C. A mass loss also occurs at 755°C, accounted for by evolved oxygen.

1.6-Diaminohexan als Schablonenverbindung in der Synthese von Zeolith ZSM-5 / 1.6-Diaminohexane as Template in the Synthesis of Zeolite ZSM-5

1987 ◽  
Vol 42 (10) ◽  
pp. 1256-1262 ◽  
Author(s):  
H. Lermer ◽  
K. K. Unger
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Infrared Spectroscopy ◽  
Reaction Time ◽  
X Ray Diffraction ◽  
X Ray ◽  
Molar Ratios ◽  
Thermal Gravimetry ◽  
Scanning Electron

Abstract A mixture characterized by the molar ratios of H2O/SiO2 = 20, SiO2/Al2O3, = 120, Na2O/SiO2 = 0.3 and 1.6 diaminohexane (DAH) as template was reacted at 182 °C. Dependent on the reaction time, the ratio of OH- /SiO2 and DAH/SiO2 ZSM-5 was crystallised with α-quartz as by-product. The materials were characterized by X-ray diffraction, scanning electron microscopy, infrared spectroscopy, thermogravimetry and differential thermal gravimetry.

scholarly journals Effects of annealing parameters on phase, structure and thermochromic properties of VO2 (M) derived from nanostructured VO2(B)

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hamdi Muhyuddin Barra ◽  
Soo Kien Chen ◽  
Nizam Tamchek ◽  
Zainal Abidin Talib ◽  
Oon Jew Lee ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Phase Transition ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
X Ray ◽  
Thermogravimetric Analyzer ◽  
Different Temperatures ◽  
Thermochromic Properties ◽  
Scanning Electron

Abstract Synthesis of thermochromic VO2 (M) was successfully done by annealing hydrothermally-prepared VO2 (B) at different temperatures and times. Conversion of the metastable VO2 (B) to the thermochromic VO2 polymorph was studied using thermogravimetric analyzer (TGA) under N2 atmosphere. Moreover, the phase and morphology of the synthesized samples were studied using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. Accordingly, the XRD scans of all the annealed samples exhibited the presence of monoclinic VO2 (M), while the FE-SEM images of the samples showed the formation of nanorods and nanospheres, particularly those heated at high temperatures (650 °C and 700 °C). Meanwhile, differential scanning calorimetry (DSC) was used to measure the phase transition temperature (τc), hysteresis, and enthalpy of the prepared VO2. Based on these results, all samples displayed a τc of about 66 °C. However, the hysteresis was high for the samples annealed at lower temperatures (550 °C and 600 °C), while the enthalpy was very low for samples heated at lower annealing time (1.5 h and 1 h). These findings showed that crystallinity and nanostructure formation affected the thermochromic properties of the samples. In particular, the sample annealed at 650 °C showed better crystallinity and improved thermochromic behavior.

scholarly journals Sintesis dan Karakterisasi Selulosa Bakteri Tercangkok Poliakrilonitril dan Teramidoksimasi Menggunakan Teknik Pra-iradiasi

2016 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Oktaviani Oktaviani ◽  
Emil Budianto ◽  
Sugiarto Danu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Acetobacter Xylinum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Thermal Gravimetry ◽  
Scanning Electron

Penelitian ini bertujuan untuk mempelajari kopolimerisasi cangkok akrilonitril pada selulosa bakteri (SB) dengan inisiasi radiasi serta penambahan hidroksilamin untuk menghasilkan gugus amidoksim. Pencangkokan akrilonitril pada SB diharapkan dapat meningkatkan ketahanan termal SB. Sedangkan SB yang bersifat sebagai pengkelat ion-ion logam berat, diharapkan dapat dihasilkan melalui penambahan hidroksilamin. Film selulosa bakteri telah berhasil dibuat dari air kelapa yang diinokulasi dengan bakteri Acetobacter xylinum. Film selulosa bakteri (SB) selanjutnya diiradiasi dengan berkas elektron pada rentang dosis 15-120 kGy, laju dosis 15 kGy/pass pada suhu 30 + 1 0C. Setelah diiradiasi, SB tersebut dikopolimerisasi cangkok dengan monomer akrilonitril. Kondisi optimum untuk kopolimerisasi cangkok akrilonitril pada SB adalah pada dosis 75 kGy, suhu 600C, waktu 3 jam, dan konsentrasi akrilonitril 30% b/b. Derajat pencangkokan tertinggi yang diperoleh adalah 56,03 %. Selulosa bakteri tercangkok akrilonitril (SB tercangkok PAN) selanjutnya diamidoksimasi. Amidoksimasi dilakukan dengan penambahan hidroksilamin hidroklorida 6 % b/v dalam pelarut metanol:air = 50:50 v/v pada pH 7, dan diperoleh waktu optimum selama 2 jam dengan densitas gugus amidoksim sebesar 5,425 mmol/ g. Hasil karakterisasi dengan Fourier Transform Infrared (FTIR) menunjukkan adanya spektrum spesifik gugus siano setelah proses pencangkokan akrilonitril pada SB dan intensitasnya menurun setelah diamidoksimasi. Hal tersebut diperkuat dengan hasil uji Scanning Electron Microscopy (SEM) yang memperlihatkan adanya gugus siano yang menempel setelah pencangkokan, dan gugus tersebut tidak terlihat lagi setelah amidoksimasi. Dari hasil uji dengan X-ray Diffraction (XRD), indeks kristalinitas SB tercangkok PAN akan semakin rendah dengan meningkatnya derajat pencangkokan dan pengujian dengan Thermal Gravimetry Analysis (TGA) menunjukkan bahwa ketahanan panas SB tercangkok PAN meningkat.

scholarly journals Synthesis and photoluminescence properties of Ba2Y3(SiO4)3F:Tm3+ blue-emitting fluorosilicate phosphors

2020 ◽  
Vol 185 ◽  
pp. 04051
Author(s):  
Junhui Yang ◽  
Huanyou Wang ◽  
Jinhua Liu ◽  
Jun Chen ◽  
Fanhua Zeng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Concentration Quenching ◽  
Photoluminescence Properties ◽  
Quenching Mechanism ◽  
Multipole Interaction ◽  
Phase Purity ◽  
X Ray ◽  
Chromaticity Coordinates ◽  
Scanning Electron

Various novel Ba2Y3(SiO4)3F:Tm3+ blue-emitting fluorosilicate materials were achieved via solid-state synthesis. The structure and phase purity of prepared Ba2Y3(SiO4)3F:xTm3+ (x = 0.001-0.10 mol) were examined by X-ray powder diffraction. The surface morphology of Ba2Y3(SiO4)3F:0.01Tm3+ was studied by scanning electron microscopy. Photoluminescence properties were systematically explored under the monitoring emission (λem = 468 nm) and excitation (λex = 302 nm) spectra. The optimum mole ratio of as-synthesized phosphors was 0.01 mol. The concentration quenching mechanism in the Ba2Y3(SiO4)3F host was due to electric multipole interaction. Particularly, the chromaticity coordinates (0.1334, 0.0474) of Ba2Y3(SiO4)3F:0.01Tm3+ are near to those of the commercial BaMgAl10O17:Eu2+. These results validated the Ba2Y3(SiO4)3F:Tm3+ fluorosilicate phosphor can be used as a good blue-emitting candidate for W-LEDs.

Synthesis and Photoluminescence of Rhombic NaLa(MoO4)2:Ln3+ Nanocrystals

2016 ◽  
Vol 16 (4) ◽  
pp. 3617-3621 ◽  
Author(s):  
Yuping Wang ◽  
Mingxia Li ◽  
Kai Pan ◽  
Rong Li ◽  
Naiying Fan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Luminescence Intensity ◽  
Dopant Concentration ◽  
Emission Spectra ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Rhombic NaLa(MoO4)2:Ln3+ (Ln = Eu and Tb) nanocrystals were synthesized by a hydrothermal method. The structures and morphologies of the nanocrystals were characterized by X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The results indicated that the crystalline size increased with increasing Na2MoO4 content. The photoluminescence properties of NaLa(MoO4)2:Ln3+ nanocrystals were investigated in detail. In the emission spectra of NaLa(MoO4)2:Eu3+ nanocrystals, the 5D0 → 7F2 is dominant, and the peak positions and spectral shapes of emissions were independent of Eu3+ concentration. The luminescence intensity increased with increasing Eu3+ concentration, up to about 10 mol%, and then decreased. In the emission spectra of NaLa(MoO4)2:Tb3+ nanocrystals, the 5D4 → 7F5 is dominant. The sample with a dopant concentration of 20 mol% showed the highest emission intensity.

Study of Calcium Magnesium Aluminate CaMgAl10O17 Formation

2015 ◽  
Vol 670 ◽  
pp. 162-167 ◽  
Author(s):  
Ekaterina A. Gavrilenko ◽  
Ekaterina E. Kuznetsova ◽  
Liliya A. Selyunina ◽  
Lyudmila N. Mishenina
Keyword(s):  
Electron Microscopy ◽  
Alkaline Earth ◽  
Sol Gel ◽  
Magnesium Aluminate ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alkaline Earth Elements ◽  
Calcium Magnesium ◽  
Scanning Electron

Aluminates of alkaline earth elements have high photoluminescence properties and resistance to UV radiation. Due to this, they are widely used in optical industry. In this work magnesium calcium aluminate was prepared by sol-gel method. The main stages of the formation of the crystalline structure CaMgAl10O17 were determined by thermal analysis, X-ray diffraction and IR spectroscopy. The surface morphology was studied using scanning electron microscopy. The ratio of elements in the product was installed by X-ray microanalysis.

Investigation on the Effects of Zn on PbTiO3

2008 ◽  
Vol 368-372 ◽  
pp. 5-7
Author(s):  
J.A. Garcia ◽  
M.U. Herrera
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Scanning Electron Microscopy ◽  
Mole Fraction ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Solid State Method ◽  
X Ray ◽  
State Method ◽  
Scanning Electron

Synthesis of Zn-doped PbTiO3 was done using solid-state method. The effects of varying amount of Zn were investigated. Stoichiometric amount of precursors were mixed and ground. The pressed mixtures were calcined at 800°C and sintered at 1,100 °C after regrinding. The samples were characterized using X-ray Diffraction (XRD), Differential Thermal Analysis (DTA), and Scanning Electron Microscopy (SEM). The XRD verifies the existence of PTO in the samples. DTA shows the thermal profile of the samples. Among the different concentrations of Zn that were added, the sample with 5% mole fraction showed the lowest melting point. For 5% mole fraction and greater, SEM images showed flattening and fusing of grains.

scholarly journals Study of α-Fe2O3@ ZnO nanoleaves: Morphological and optical study

2020 ◽  
Vol 2 (1) ◽  
pp. 118-124
Author(s):  
Parastoo Khalili ◽  
◽  
Majid Farahmandjou ◽  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Weight Percent ◽  
Optical Study ◽  
X Ray Diffraction ◽  
Sem Images ◽  
X Ray ◽  
Transmission Electron ◽  
Stretching Vibrations ◽  
Scanning Electron

In this paper, α-Fe2O4@ZnO nanoparticles (NPs) were synthesized by coprecipitation method in the presence of PVP and EG surfactants. The samples were charactrized by x-ray fluorescence (XRF), x-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), and fourier transform infrared spectroscopy (FTIR). The XRD results exhibited rhombohedral α-Fe2O3 and wurtzite structure of ZnO. The SEM images showed that the NPs changed from rod-shape to nanoleaves particles after heat treatment. The TEM studies displayed the formation of Fe2O3@ZnO core-shell of as-synthesized NPs. The stretching vibrations peaks in FTIR in the wavenumber of 532 cm-1 and 473 cm-1 ascribed to the Fe and Zn groups. The XRF data indicated decreasing of the Fe weight percent from 22 %Wt. to 25 %Wt., after heat treatment.

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