Structure and Photoluminescent Properties of Microstructural YBO3 : Eu3+ Nanocrystals

2007 ◽  
Vol 7 (2) ◽  
pp. 593-601 ◽  
Author(s):  
Guohui Pan ◽  
Hongwei Song ◽  
Lixin Yu ◽  
Zhongxin Liu ◽  
Xue Bai ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Luminescent Properties ◽  
Radiative Transition ◽  
Surface Site ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
Hydrothermal Temperature ◽  
Transmission Electron ◽  
Site Selective ◽  
Radiative Transition Rate

YBO3 : Eu3+ nanocrystals (NCs) were prepared by a hydrothermal method and characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy. The results demonstrate that morphology and structure of the NCs varied strongly with hydrothermal temperature. Their luminescent properties were investigated in comparison to the bulk. A large number of NO&minus3 groups were adsorbed at the surface of hydrothermal products, which acted as luminescent killers; Two symmetry sites of Eu3+ ions in NCs, the interior and the surface sites, were identified by the site-selective excitation and time-resolved emission experiments; The intensity ratio of 5D0–7F2 to 5D0–7F1 of Eu3+ at the surface site increased greatly than that at the interior site; as a result, the chromaticity was improved; The total radiative transition rate of 5D0–ΣJ7Fj for Eu3+ at the surface site was 3–5 times larger than that at the interior.

scholarly journals Synthesis, Structure, and Luminescent Properties of Europium-Doped Hydroxyapatite Nanocrystalline Powders

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Carmen Steluta Ciobanu ◽  
Simona Liliana Iconaru ◽  
Florian Massuyeau ◽  
Liliana Violeta Constantin ◽  
Adrian Costescu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Textural Properties ◽  
Average Crystallite Size ◽  
Luminescent Properties ◽  
Nanocrystalline Powders ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Vibrational Studies ◽  
20 Nm

The luminescent europium-doped hydroxyapatite (Eu:HAp, Ca10−xEux(PO4)6(OH)2) with0≤x≤0.2nanocrystalline powders was synthesized by coprecipitation. The structural, morphological, and textural properties were well characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The vibrational studies were performed by Fourier transform infrared, Raman, and photoluminescence spectroscopies. The X-ray diffraction analysis revealed that hydroxyapatite is the unique crystalline constituent of all the samples, indicating that Eu has been successfully inserted into the HAp lattice. Eu doping inhibits HAp crystallization, leading to a decrease of the average crystallite size from around 20 nm in the undoped sample to around 7 nm in the sample with the highest Eu concentration. Furthermore, the samples show the characteristic5D0→7F0transition observed at 578 nm related to Eu3+ions distributed on Ca2+sites of the apatitic structure.

Luminescent properties of Y2O3:Eu3+ nanophosphor prepared from urea added precursor using flame spray pyrolysis

2009 ◽  
Vol 24 (8) ◽  
pp. 2584-2588 ◽  
Author(s):  
Jae Seok Lee ◽  
Se Jin Kim ◽  
Tae Kon Kim ◽  
Rajiv K. Singh ◽  
Madhav B. Ranade
Keyword(s):  
Electron Microscopy ◽  
Spray Pyrolysis ◽  
Red Light ◽  
Luminescent Properties ◽  
Flame Spray Pyrolysis ◽  
Cubic Phase ◽  
Flame Spray ◽  
X Ray Diffraction ◽  
Synthesis Conditions ◽  
Transmission Electron

Y2O3:Eu3+ nanophosphor was synthesized by flame spray pyrolysis (FSP) from urea added nitrate based liquid precursor. In this study, urea serves as fuel and subsequently provides additional heat in the flame zone during the synthesis of phosphor particles. The end product shows cubic phase Y2O3:Eu3+ nanophosphor successfully prepared by FSP without heat treatment. The influence of synthesis conditions such as different mol of urea and nitrate source materials in aqueous solution, and doping concentration on luminescent properties, were investigated. The characteristics of nanophosphor such as crystallinity and morphology under various experiments of conditions were carried out by x-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM). The particle size of product was found to be in the range of 20–30 nm from transmission electron microscopy (TEM). In photoluminescence (PL) properties, Y2O3:Eu3+ nanophosphor emitted red light with a peak wavelength of 609 nm when excited with 398 nm wavelength photons.

Preparation and Luminescence Properties of ZnS: Cu/Fe Nanocrystalline

2014 ◽  
Vol 1033-1034 ◽  
pp. 1054-1057
Author(s):  
Xiang Zhang ◽  
Jin Liang Huang ◽  
Li Hua Li
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Thioglycolic Acid ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zinc Blende ◽  
Transmission Electron ◽  
Fe Nanoparticles

ZnS: Cu/Fe nanocrystals were synthesized by hydrothermal method with thioglycolic acid as a stabilizer. The phases, grain size and luminescent properties of the nanocrystals were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and fluorescence photometer respectively. The results showed that ZnS: Cu/Fe nanoparticles have a particle size about 7nm and possess a cubic zinc blende crystal structure. The luminous intensity of ZnS: Cu/Fe nanocrystals was strongly when they were reacted at 140°C for 12 hours.

Luminescent Properties of La3PO7:Eu3+ Nanoparticles

2008 ◽  
Vol 8 (3) ◽  
pp. 1410-1413 ◽  
Author(s):  
Shaozhe Lü ◽  
Jishen Zhang
Keyword(s):  
Charge Transfer Band ◽  
Emission Spectra ◽  
Local Environment ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
Time Resolved ◽  
Transmission Electron ◽  
Light Excitation ◽  
Average Size

La3PO7:Eu3+ samples were prepared by combustion and annealing and characterized by X-ray diffraction and transmission electron microscopy. It was found that the average size of the particles is about 80 nm. The red emission from the 5D0 → 7F2 transition of the Eu3+ ions under ultraviolet light excitation is much stronger than the orange emission from the 5D0 → 7F1 transition. The emission spectra, charge transfer band, laser selective excitation spectra, and time-resolved spectra indicate that symmetry of the local environment of Eu3+ lacks an inversion center and Eu3+ ions occupy at least two types of sites in the La3PO7 crystal. The superior color chromaticity compared to other phosphates and borates doped with Eu3+ means La3PO7:Eu3+ may have potential as a luminescent material.

Controllable synthesis, characterization, and electrochemical properties of manganese oxide nanoarchitectures

2008 ◽  
Vol 23 (3) ◽  
pp. 780-789 ◽  
Author(s):  
Lichun Zhang ◽  
Liping Kang ◽  
Hao Lv ◽  
Zhikui Su ◽  
Kenta Ooi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electrochemical Properties ◽  
Manganese Oxide ◽  
Manganese Oxides ◽  
Hydrothermal Reaction ◽  
Reaction Times ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Hydrothermal Temperature ◽  
Transmission Electron

Flowerlike manganese oxide microspheres and cryptomelane-type manganese oxide nanobelts were selectively synthesized by a simple decomposition of KMnO4 under mild hydrothermal conditions without using template or cross-linking reagents. The effect of varying the hydrothermal times and temperatures on the nanostructure, morphology, compositional, and electrochemical properties of the obtained manganese oxides was investigated. X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies showed that the flowerlike manganese oxide microspheres could be obtained at relatively low hydrothermal temperatures, while high hydrothermal temperatures were favorable for the formation of cryptomelane-type manganese oxide nanobelts. A morphology and crystalline evolution of the nanostructures was observed as the hydrothermal temperature was increased from 180 to 240 °C. On the basis of changing the temperatures and hydrothermal reaction times, the formation mechanism of cryptomelane-type manganese oxide nanobelts is discussed. Cyclic voltammetry (CV) was used to evaluate the electrochemical properties of the obtained manganese oxide nanostructures, and the results show that the electrochemical properties depend on their shape and crystalline structure. This easily controllable, template-free, and environmentally friendly method has the potential for being used in syntheses of manganese oxide nanomaterials with uniform morphologies and crystal structures.

Facile Controlled Synthesis of Manganese Oxide Hierarchical Microspheres by Hydrothermal Method

2011 ◽  
Vol 688 ◽  
pp. 107-115 ◽  
Author(s):  
Dong Yan Li ◽  
Yun Fa Chen
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Reaction ◽  
Nitrogen Adsorption ◽  
Bet Surface Area ◽  
Formation Mechanisms ◽  
X Ray Diffraction ◽  
Tem Analysis ◽  
Hydrothermal Temperature ◽  
Transmission Electron ◽  
Hierarchical Microspheres

MnO2hierarchical microsphere has been synthesized by a facile and direct hydrothermal reaction between KMnO4and HCl without the aids of catalysts, surfactants or templates. The as-prepared microsphere, as characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) analysis and nitrogen adsorption and desorption, is in form of K0.27MnO2(H2O )0.54, with a flower-like hierarchical microsphere structure and a BET surface area value of 52 m2/g. The morphology of the product can be simply tailed by controlled by reaction temperature or period and crystallinity can be modified by changing the concentrate of KMnO4. In general, excessive KMnO4and low hydrothermal temperature are favor to forming flower-like hierarchical structure. Besides, the formation mechanisms of the hierarchical schemes are proposed.

Shape-Controlled Synthesis of Gadolinium Oxide Nanostructure via Facile Process

2012 ◽  
Vol 182-183 ◽  
pp. 265-269
Author(s):  
Qing Zhang ◽  
Pei Wen Hao ◽  
Xin Qu ◽  
Chun Wang ◽  
Rui Xia Li
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Process ◽  
X Ray Diffraction ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Heating Treatment ◽  
Shape Controlled ◽  
Low Dimensional ◽  
Hydrolysis Of

A facile method to selectively synthesize nano-scaled Gd2O3 with different morphology such as nanosheres and nanorods has been developed in our report. The precursors GdOHCO3 can be prepared by a two-step hydrothermal process via homogeneous generation of hydroxide ions through the hydrolysis of urea, and the formation of different morphology structures were obtained under different reaction temperatures. After further heating treatment, a transformation from GdOHCO3 to cubic Gd2O3 takes place. The morphology and size of nano Gd2O3 strongly depend on that of the precursors GdOHCO3. The X-ray diffraction, transmission electron microscopy and scanning electron microscopy were employed to characterize the as-obtained low-dimensional nanostructures. And the effects of hydrothermal temperature, solvent and urea concentration on the morphologies of the products were also studied.

Simplified Synthesis and Luminous Mechanism of Eu2+-Doped α-Si3N4 Nanowires with Strong Green Luminescent Properties

2017 ◽  
Vol 727 ◽  
pp. 635-641 ◽  
Author(s):  
Rui Su ◽  
Zhi Feng Huang ◽  
Fei Chen ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Broad Band ◽  
Luminescent Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Broad Band Emission ◽  
Band Emission ◽  
Nitridation Process ◽  
Transmission Electron

Ultra-long, single crystal, Eu-doped α-Si3N4 nanowires were prepared by a simple approach involving nitriding Eu-doped cryomilled nanocrystalline Si powder in NH3 flow at 1350 °C for 4 h. Phases, chemical composition and microcosmic feature of cryomilled powders and as-prepared nanowires were tested by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), respectively. The results suggested that Eu was successfully introduced into Si lattice after the cryomilling process and then entered into the lattice of α-Si3N4 during the nitridation process. The as-synthesized Eu-doped α-Si3N4 nanowires had highly uniform dimension with 20~30 nm in diameter and ~100 μm in length. The room temperature photoluminescence (PL) spectrum of as-synthesized nanowires showed a broad band emission center at 570 nm which was attributed to the transition from 4f65d to 4f7 in Eu2+. The transition from Eu3+ to Eu2+ during nitridation process was tested by X-ray photoelectron spectroscopy (XPS).

HYDROTHERMAL SYNTHESIS OF α-MoO3 NANORODS FOR NO2 DETECTION

2012 ◽  
Vol 11 (06) ◽  
pp. 1240044 ◽  
Author(s):  
SHOULI BAI ◽  
SONG CHEN ◽  
YUAN TIAN ◽  
RUIXIAN LUO ◽  
DIANQING LI ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Molybdenum Trioxide ◽  
Hydrothermal Process ◽  
High Sensitivity ◽  
X Ray Diffraction ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Transmission Electron ◽  
Ft Ir

Thermodynamically stable molybdenum trioxide nanorods have been successfully synthesized by a simple hydrothermal process. The product exhibits high-quality, single-crystalline layered orthorhombic structure (α- MoO3 ), and aspect ratio over 20 by characterizations of X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and Fourier transform infrared (FT-IR). The growth mechanism of α- MoO3 nanorods can be understood by electroneutral and dehydration reaction, which is highly dependent on solution acidity and hydrothermal temperature. The sensing tests show that the sensor based on MoO3 nanorods exhibits high sensitivity to NO2 and is not interferred by CO and CH4 , which makes this kind sensor a competitive candidate for NO2 detection. The intrinsic sensing performance of MoO3 maybe arise from its nonstoichiometry of MoO3 owing to the presence of Mo5+ and oxygen vacancy in MoO3 lattice, which has been confirmed by X-ray photoelectron spectroscopy (XPS) analysis. The sensing mechanism of MoO3 for NO2 is also discussed.

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