scholarly journals Effect of Ceramic Formation on the Emission of Eu3+ and Nd3+ Ions in Double Perovskites

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 5996
Author(s):  
Natalia Miniajluk-Gaweł ◽  
Bartosz Bondzior ◽  
Karol Lemański ◽  
Thi Hong Quan Vu ◽  
Dagmara Stefańska ◽  
...  
Keyword(s):  
Excited Level ◽  
Branching Ratio ◽  
Green Emission ◽  
Blue Shift ◽  
Quality Parameter ◽  
Sintering Process ◽  
X Ray ◽  
Dipole Emission ◽  
Structure Morphology ◽  
Powder Samples

Herein, the structure, morphology, as well as optical properties of the powder and ceramic samples of Ba2MgWO6 are presented. Powder samples were obtained by high temperature solid-state reaction, while, for the ceramics, the SPS technique under 50-MPa pressure was applied. The morphology of the investigated samples showed some agglomeration and grains with a submicron size of 490–492 µm. The theoretical density and relative density of ceramics were calculated using the Archimedes method. The influence of sample preparation on the position, shape, and character of the host, as well as dopants emission was investigated. Sample sintering enhances regular emission of WO6 groups causing a blue shift of Ba2MgWO6 emission. Nonetheless, under X-ray excitation, only the green emission of inversion WO6 group was detected. For the ceramic doped with Eu3+ ions, the emission of both host and dopant was detected. However, for the powder efficient host to activator energy, the transfer process occurred, and only the magnetic dipole emission of Eu3+ was detected. The intensity of Nd3+ ions of Ba2MgWO6 powder sample is five times higher than for the ceramic. The sintering process reduces inversion defects and creates a highly symmetrical site of neodymium ions. The emission of Ba2MgWO6:Nd3+ consists of transitions from the 4F3/2 excited level to the 4IJ multiplet states with the dominance of the 4F3/2→4I11/2 one. The spectroscopic quality parameter and branching ratio of Nd3+ emission are presented.

Spectrophotometric Investigation on the Growth Mechanism of a Single Tapered CuO Nanowire

2009 ◽  
Vol 1206 ◽  
Author(s):  
Anindita Chatterjee ◽  
C-Y Huang ◽  
S-B Liu ◽  
S-Y Wu ◽  
Chia-Liang Cheng
Keyword(s):  
Surface Defects ◽  
Green Emission ◽  
Cost Effective ◽  
Blue Shift ◽  
Energy Dispersive ◽  
X Ray ◽  
Cuo Nanowires ◽  
Cuo Nanowire ◽  
Photoluminescence Studies ◽  
20 Nm

AbstractIn this study, well separated tapered CuO nanowires have been synthesized on copper grid using an easy and cost effective thermal oxidation method. A set of spectroscopic investigations have been performed on one single tapered CuO nanowire using Energy Dispersive X-ray, confocal Raman and confocal Photoluminescence spectroscopy to get insight into the mechanism of growth of the nanowires. Energy Dispersive X-ray studies reveal crystallization process of CuO nanowires occur from Cu/Cu2O mixed phase state to pure CuO structure. Raman measurements indicate a little sharpening of the Raman peaks with increasing growth temperature of the nanowires starting from 400°C to 600°C. Photoluminescence studies were carried out by mapping along the length of the nanowire to investigate the growth as well as optical properties of a single tapered CuO nanowire. As the diameter of the single tapered CuO nanowire decreases, the green emission of the nanowire gradually shifts towards the higher energy side. A steady blue shift of 20 nm of the photoluminescence peak has been attributed to the nanosize effect of the tapered nanowire along the length and enhanced surface defects.

Mg-Induced Shift of Band Edge in ZnO:Mg Probed by the Visible Luminescence

2012 ◽  
Vol 590 ◽  
pp. 73-78
Author(s):  
Shu Xia Guo ◽  
Ji Wu Li
Keyword(s):  
Room Temperature ◽  
Blue Emission ◽  
Green Emission ◽  
Blue Shift ◽  
X Ray Diffraction ◽  
X Ray ◽  
Visible Luminescence ◽  
Co Precipitation ◽  
Mg Substitution ◽  
Mg Doped

Mg-doped ZnO was synthesized using a co-precipitation technique. X-ray diffraction (XRD) measurements and absorption spectra show that Mg ions are doped into the lattice positions of ZnO. In the room temperature photoluminescence (PL) spectra, two emission bands, ultraviolet (UV) and visible, were observed. Either of two emissions shows a blue-shift. The visible emission band is composed of the green emission and the blue emission. The amount of blue-shift in green emission is 0.03 eV, about half of the amount of blue-shift in blue emission. Mg substitution raises and lowers conduction- and valence-band edges, respectively.

SYNTHESIS, STRUCTURE, AND LUMINESCENCE PROPERTIES OF ZnSnO3 NANOWIRES

NANO ◽  
2012 ◽  
Vol 07 (02) ◽  
pp. 1250013 ◽  
Author(s):  
SOYEON AN ◽  
CHANGHYUN JIN ◽  
HYUNSU KIM ◽  
SANGMIN LEE ◽  
BONGYONG JEONG ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Green Emission ◽  
Blue Shift ◽  
Zno Nanowires ◽  
X Ray Diffraction ◽  
Ultraviolet Emission ◽  
Violet Emission ◽  
X Ray ◽  
Transmission Electron

ZnSnO3 nanowires were synthesized on Si substrates by thermal evaporation of a mixture of ZnO, SnO2 and graphite powders. The nanowires were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and photoluminescence spectroscopy. The ZnSnO3 nanowires varied from 10 to 100 nm in diameter and up to a few hundred of micrometers in length. Transmission electron microscopy and X-ray diffraction revealed that the nanowires are multiphase nanostructures containing ZnSnO3, Zn2SnO4, ZnO, and SnO2 phases. Photoluminescence measurements showed that ZnSnO3 nanowires had a sharp ultraviolet emission peak at approximately 375 nm as well as a broad green emission band centered at approximately 510 nm. The violet emission of ZnSnO3 nanowires exhibits a blue shift by approximately 5 nm compared to that of ZnO nanowires and the visible emission of ZnO nanowires shifted from the orange region to the green region, which should be attributed to the narrowing of Eg. Thermal annealing enhanced the green emission but degraded the ultraviolet emission of the ZnSnO3 nanowires. In addition, the origin of the enhanced luminescence of ZnSnO3 nanowires compared to ZnO and SnO2 nanowires is discussed.

Synthesis and Upconversion Luminescence of Water-Soluble of GdF3:Yb3+/Er3+ Nanoparticles

2016 ◽  
Vol 16 (4) ◽  
pp. 3981-3984 ◽  
Author(s):  
Gejihu De ◽  
B Asina ◽  
Wujiseleng Ma
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thermal Decomposition ◽  
Upconversion Luminescence ◽  
Green Emission ◽  
Water Soluble ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Morphology

Water-soluble Yb3+/Er3+ doped GdF3 nanocrystals were prepared using a thermal decomposition synthesis route. The crystal structure, morphology and up-conversion spectra of the samples were characterized using X-ray powder diffractometry, transmission electron microscopy and a fluores- cence spectrophotometer with single-wavelength diode laser of 980 nm. In Yb3+- and Er3+-codoped GdF3 nanocrystals, the relative intensity of green emission became stronger as the sample changed from water-soluble nanoparticles to hexane-dispersed nanoparticles. The synthesis of such monidisperse, water-soluble, lanthanide-doped upconvertion particles will open new opportunities in targeting and drug delivery applications.

Growth Kinetics of Quantum Size ZnO Particles

1998 ◽  
Vol 536 ◽  
Author(s):  
E. M. Wong ◽  
J. E. Bonevich ◽  
P. C. Searson
Keyword(s):  
Growth Kinetics ◽  
Ostwald Ripening ◽  
Chemical Potential ◽  
Colloidal Suspensions ◽  
Green Emission ◽  
Blue Shift ◽  
Constant Current ◽  
Mass Model ◽  
Zno Particles ◽  
Kinetics Of

AbstractColloidal chemistry techniques were used to synthesize ZnO particles in the nanometer size regime. The particle aging kinetics were determined by monitoring the optical band edge absorption and using the effective mass model to approximate the particle size as a function of time. We show that the growth kinetics of the ZnO particles follow the Lifshitz, Slyozov, Wagner theory for Ostwald ripening. In this model, the higher curvature and hence chemical potential of smaller particles provides a driving force for dissolution. The larger particles continue to grow by diffusion limited transport of species dissolved in solution. Thin films were fabricated by constant current electrophoretic deposition (EPD) of the ZnO quantum particles from these colloidal suspensions. All the films exhibited a blue shift relative to the characteristic green emission associated with bulk ZnO. The optical characteristics of the particles in the colloidal suspensions were found to translate to the films.

scholarly journals Comprehensive Characterisation of the Ketoprofen-β-Cyclodextrin Inclusion Complex Using X-ray Techniques and NMR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4089
Author(s):  
Katarzyna Betlejewska-Kielak ◽  
Elżbieta Bednarek ◽  
Armand Budzianowski ◽  
Katarzyna Michalska ◽  
Jan K. Maurin
Keyword(s):  
Nmr Spectroscopy ◽  
Inclusion Complex ◽  
Crystal And Molecular Structure ◽  
Binding Constants ◽  
Nmr Studies ◽  
X Ray ◽  
Cyclodextrin Inclusion ◽  
Powder Samples ◽  
Cyclodextrin Inclusion Complex ◽  
Co Precipitation

Racemic ketoprofen (KP) and β-cyclodextrin (β-CD) powder samples from co-precipitation (1), evaporation (2), and heating-under-reflux (3) were analysed using X-ray techniques and nuclear magnetic resonance (NMR) spectroscopy. On the basis of NMR studies carried out in an aqueous solution, it was found that in the samples obtained by methods 1 and 2, there were large excesses of β-CD in relation to KP, 10 and 75 times, respectively, while the sample obtained by method 3 contained equimolar amounts of β-CD and KP. NMR results indicated that KP/β-CD inclusion complexes were formed and the estimated binding constants were approximately 2400 M−1, showing that KP is quite strongly associated with β-CD. On the other hand, the X-ray single-crystal technique in the solid state revealed that the (S)-KP/β-CD inclusion complex with a stoichiometry of 2:2 was obtained as a result of heating-under-reflux, for which the crystal and molecular structure were examined. Among the methods used for the preparation of the KP/β-CD complex, only method 3 is suitable.

scholarly journals Controlled Synthesis of CuS and Cu9S5 and Their Application in the Photocatalytic Mineralization of Tetracycline

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 899
Author(s):  
Murendeni P. Ravele ◽  
Opeyemi A. Oyewo ◽  
Damian C. Onwudiwe
Keyword(s):  
Electron Microscopy ◽  
Visible Light ◽  
Blue Shift ◽  
X Ray Diffraction ◽  
X Ray ◽  
Copper Sulfides ◽  
Transmission Electron ◽  
Single Source Precursor ◽  
Pure Phase ◽  
Pure Phases

Pure-phase Cu2−xS (x = 1, 0.2) nanoparticles have been synthesized by the thermal decomposition of copper(II) dithiocarbamate as a single-source precursor in oleylamine as a capping agent. The compositions of the Cu2−xS nanocrystals varied from CuS (covellite) through the mixture of phases (CuS and Cu7.2S4) to Cu9S5 (digenite) by simply varying the temperature of synthesis. The crystallinity and morphology of the copper sulfides were studied using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), which showed pure phases at low (120 °C) and high (220 °C) temperatures and a mixture of phases at intermediate temperatures (150 and 180 °C). Covellite was of a spherical morphology, while digenite was rod shaped. The optical properties of these nanocrystals were characterized by UV−vis–NIR and photoluminescence spectroscopies. Both samples had very similar absorption spectra but distinguishable fluorescence properties and exhibited a blue shift in their band gap energies compared to bulk Cu2−xS. The pure phases were used as catalysts for the photocatalytic degradation of tetracycline (TC) under visible-light irradiation. The results demonstrated that the photocatalytic activity of the digenite phase exhibited higher catalytic degradation of 98.5% compared to the covellite phase, which showed 88% degradation within the 120 min reaction time using 80 mg of the catalysts. The higher degradation efficiency achieved with the digenite phase was attributed to its higher absorption of the visible light compared to covellite.

scholarly journals Hydrothermal Synthesis, Characterization and Exploration of Photocatalytic Activities of Polyoxometalate: Ni-CoWO4 Nanoparticles

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 456
Author(s):  
Fahad A. Alharthi ◽  
Hamdah S. Alanazi ◽  
Amjad Abdullah Alsyahi ◽  
Naushad Ahmad
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Structure Morphology ◽  
Photocatalytic Activities ◽  
Ft Ir ◽  
Photocatalytic Reactions ◽  
Cobalt Tungstate

This study demonstrated the hydrothermal synthesis of bimetallic nickel-cobalt tungstate nanostructures, Ni-CoWO4 (NCW-NPs), and their phase structure, morphology, porosity, and optical properties were examined using X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS), high resolution Transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller (BET) and Raman instruments. It was found that as-calcined NCW-NPs have a monoclinic phase with crystal size ~50–60 nm and is mesoporous. It possessed smooth, spherical, and cubic shape microstructures with defined fringe distance (~0.342 nm). The photocatalytic degradation of methylene blue (MB) and rose bengal (RB) dye in the presence of NCW-NPs was evaluated, and about 49.85% of MB in 150 min and 92.28% of RB in 90 min degraded under visible light. In addition, based on the scavenger’s study, the mechanism for photocatalytic reactions is proposed.

Determination of crystallinity of Chinese handmade papers by means of X-ray diffraction

2020 ◽  
Vol 41 (2) ◽  
pp. 69-86
Author(s):  
Peng Liu ◽  
Hongbin Zhang ◽  
Sinong Wang ◽  
Hui Yu ◽  
Bingjie Lu ◽  
...  
Keyword(s):  
Negative Influence ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Eulaliopsis Binata ◽  
Different Types ◽  
Powder Samples ◽  
Xrd Patterns ◽  
Xrd Method

AbstractThe crystallinity indices (CrI) of Chinese handmade papers were investigated using the X-ray diffraction (XRD) method. Four Chinese handmade papers, Yingchun, Zhuma, Yuanshu and Longxucao papers were used as model substrates of mulberry bark, ramie, bamboo and Eulaliopsis binata papers, respectively. Two forms of the paper samples, paper sheets and their comminuted powders, were used in this study. The results showed that their XRD patterns belong to the cellulose-I type and Iβ dominates the cellulose microstructure of these paper samples. Moreover, it was found that the microstructures and CrIs of cellulose of these papers were changed by the grinding treatment. This work suggested that the sheet form of the handmade papers is suitable to determine CrI by XRD, despite the contribution of non-cellulosic components in the papers. The order of CrIs for these paper sheet samples was Yingchun, Zhuma, Longxucao and Yuanshu papers. Besides CrIs, differences in cross-sectional areas of the crystalline zone of cellulose can be used for comparing different types of handmade papers. It was also found that the CrIs and crystallite size of paper cellulose varied between the sheet samples and the powder samples, illustrating that the pulverisation has a negative influence on the microstructure of the handmade papers.

Sintering Process of Nd:YAG Transparent Ceramic

2013 ◽  
Vol 281 ◽  
pp. 475-479
Author(s):  
Bo Wang ◽  
Quan Xi Cao ◽  
Guang Xu ◽  
Sen Tian
Keyword(s):  
Grain Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Crystal Structures ◽  
Heating Rate ◽  
Optical Transmittance ◽  
Sintering Process ◽  
X Ray ◽  
Polycrystalline Ceramics ◽  
Scanning Electron

1.0at% Nd:YAG polycrystalline ceramics were sintered at 1420°C, 1500°C, 1600°C and 1730°C respectively by different heating rate (1°C/min and 5°C/min). The crystal structures were indexed by X-ray diffractometer (XRD). The microstructure and the grain size of the samples were characterized by scanning electron microscope (SEM). The optical transmittance spectra of the samples were measured using V-570 UV spectrophotometer. The sintering process of Nd:YAG ceramics and the effect of heating rate on the microstructure of samples have been investigated.

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