Fabrication, characterization and chemical modification of anthracene based nanostructures

2007 ◽  
Vol 22 (10) ◽  
pp. 2719-2726 ◽  
Author(s):  
Alka Gupta ◽  
Shubhra Goel ◽  
Ranjana Mehrotra ◽  
H.C. Kandpal
Keyword(s):  
Electron Microscopy ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Reaction Chamber ◽  
Covalent Modification ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Ammonia Vapor ◽  
Reaction Products ◽  
Vapor Deposition Technique

Anthracene based nano/microstructures of different sizes and shapes like tubes/fibers are synthesized using a simple open air chemical vapor deposition technique. Thermal solid phase reaction between anthracene 9-carboxylic acid and calcium oxide reported recently [H. Liu et al., J. Am. Chem. Soc.125, 10794 (2003)] is used to obtain organic molecular nanostructures. The products of temperature (320 °C) induced reaction get deposited on the substrates placed inside the reaction chamber as well as on the inner walls in different nano/micrometer forms, tubes/rods/fibers and having different sizes. Structural characterization of the reaction products is performed using optical microscopy, field emission electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Chemical composition studies are conducted using infrared (IR), nuclear magnetic resonance (NMR), and gas chromatography (GC)-Mass spectroscopy, as well as elemental analysis. IR studies of the nanostructures obtained on the substrate using IR spectroscopy reveal the presence of C=O groups, the confirmatory evidence of which is obtained using energy dispersive x-ray spectroscopic (EDS) analysis. Interaction study of the C=O groups with ammonia vapor is conducted and resulting changes are monitored using Fourier transform infrared (FTIR). A strong covalent modification of anthracene based structures by exposure to ammonia molecules is indicated.

Preparation and Characteristics of Eu and Dy Doped Sr4Al14O25 Phosphor

2008 ◽  
Vol 569 ◽  
pp. 249-252 ◽  
Author(s):  
Hom Nath Luitel ◽  
Takanori Watari ◽  
Toshio Torikai ◽  
Mitsunori Yada
Keyword(s):  
Electron Microscopy ◽  
Solid Phase ◽  
Emission Peak ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
X Ray Diffraction ◽  
Green Color ◽  
X Ray ◽  
Initial Intensity ◽  
Scanning Electron

Sr4Al14O25:Eu2+, Dy3+ long persistent phosphors with different B, Eu and Dy contents were prepared by solid phase reaction at various temperatures in H2/N2=1/9 atmosphere. X- ray diffraction and scanning electron microscopy observations showed that, when the phosphor was doped with 40 at% B, single dense Sr4Al14O25 phase was formed but for the samples with less than 40 at% B, mixed phases containing SrAl12O19 and SrAl2O4 were observed while for higher B content (100 at%) SrAl2B2O7 phases appeared. The phosphor showed emission peak centered at 500 nm with blue green color. When 40 at% of H3BO3 was added and doped with 4 at% of Eu and 8 at% of Dy, it showed the maximum initial intensity of 3170 mcd.m-2 and the longest persistency which is greater than 20 h over value of 5 mcd.m-2.

Influence of ultrasonic vibrations on the combustion of condensed systems with solid-phase reaction products

1984 ◽  
Vol 20 (6) ◽  
pp. 669-672 ◽  
Author(s):  
Yu. M. Maksimov ◽  
A. I. Kirdyashkin ◽  
A. G. Merzhanov ◽  
L. G. Raskolenko
Keyword(s):  
Solid Phase ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Ultrasonic Vibrations ◽  
Reaction Products ◽  
Condensed Systems

scholarly journals Formation Mechanism of High-Purity Ti2AlN Powders under Microwave Sintering

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5356
Author(s):  
Weihua Chen ◽  
Jiancheng Tang ◽  
Xinghao Lin ◽  
Yunlong Ai ◽  
Nan Ye
Keyword(s):  
Electron Microscopy ◽  
Formation Mechanism ◽  
High Purity ◽  
Solid Phase ◽  
Raw Materials ◽  
Microwave Sintering ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Scanning Calorimetry ◽  
Transmission Electron

In the present study, high-purity ternary-phase nitride (Ti2AlN) powders were synthesized through microwave sintering using TiH2, Al, and TiN powders as raw materials. X-ray diffraction (XRD), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were adopted to characterize the as-prepared powders. It was found that the Ti2AlN powder prepared by the microwave sintering of the 1TiH2/1.15Al/1TiN mixture at 1250 °C for 30 min manifested great purity (96.68%) with uniform grain size distribution. The formation mechanism of Ti2AlN occurred in four stages. The solid-phase reaction of Ti/Al and Ti/TiN took place below the melting point of aluminum and formed Ti2Al and TiN0.5 phases, which were the main intermediates in Ti2AlN formation. Therefore, the present work puts forward a favorable method for the preparation of high-purity Ti2AlN powders.

Stable Solid-Phase Ohmic Contacts to n-GaAs with Diffusion Barriers

1988 ◽  
Vol 126 ◽  
Author(s):  
E. Kolawa ◽  
C. W. Nieh ◽  
W. Flick ◽  
J. Molarius ◽  
M-A. Nicolet
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ohmic Contacts ◽  
Solid Phase ◽  
Diffusion Barriers ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Resistivity Measurements ◽  
Gaas Substrates ◽  
Transmission Electron

ABSTRACTContacts to GaAs substrates with n-type epilayers formed by GaAs/Ni/Ge/WN/Au, GaAs/Ni/Ge/Ni/WN/Au and GaAs/Ge/ Ni/WN/Au systems were investigated. Ohmic contacts in these systems were formed by a solid-phase reaction between Ni/Ge and GaAs. Interfacial reaction and electrical properties of these contacts are characterized by backscattering spectrometry, transmission electron microscopy and contact resistivity measurements. Resistivities in the 10−δ Ω cm range are achieved.

Prepare of ZnAl2O4/-Al2O3 complex substrates and growth of GaN films

2001 ◽  
Vol 693 ◽  
Author(s):  
Z.X. Bi ◽  
R. Zhang ◽  
W. P. Li ◽  
X.S. Wang ◽  
S.L. Gu ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Single Crystal ◽  
Solid Phase ◽  
Chemical Vapor ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
X Ray Diffraction ◽  
Zno Film ◽  
Result Show ◽  
Oriented Single Crystal

AbstractWith the solid phase reaction between the ZnO film and -Al2O3 substrate, the ZnAl2O4/-Al2O3 complex substrate have been prepared. GaN films were then directly grown on this new kind of substrate using light-radiation heating low-pressure metalorganic chemical vapor deposition (LRH-LP-MOCVD) without any nitride buffer layer. The structure and surface morphology of the ZnAl2O4/-Al2O3 substrates and GaN epilayers have been characterized by employing X-ray diffraction (XRD) and scanning electron microscope (SEM). The result show that as the thickness of ZnAl2O4 layer is increased, the film changes from a (111)-oriented single crystal to a poly-crystal, together with the surface morphology transforms from uniform islandsa a to the bulgy-line structure, leading to GaN films grown on ZnAl2O4/ -Al2O3 substrates varying from c-axis oriented single-crystal to poly-crystal.

Facile composite synthesis and photoluminescence of NaGd(MoO4)2: Ln3+ (Ln = Eu, Tb) submicrometer phosphors

2009 ◽  
Vol 24 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Bing Yan ◽  
Jianhua Wu
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Solid Phase ◽  
Hydrothermal Process ◽  
Reaction Process ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Average Grain Size ◽  
Temperature And Humidity ◽  
Crystalline Water

NaGd(MoO4)2:Ln3+ (Ln = Eu, Tb) submicrometer phosphors have been synthesized by a composite method including the solid state reaction process at room temperature and the hydrothermal process. It is revealed that temperature and humidity have an influence on the reaction rate and that higher temperature and humidity can speed up the reaction process. Crystalline water is necessary for the solid phase reaction at room temperature. The x-ray diffraction (XRD) patterns indicate that NaGd(MoO4)2:Ln3+ (Ln = Eu, Tb) submicrometer phosphors crystallize well with the scheelite structure. Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images illustrate that the average grain size of NaGd(MoO4)2:Ln3+ is about 225 nm without conglomeration. The luminescent lifetime and quantum efficiency for NaGd(MoO4)2:Eu3+ are determined.

X-ray emission during the combustion of condensed systems with solid-phase reaction products

2014 ◽  
Vol 454 (1) ◽  
pp. 5-7
Author(s):  
A. I. Kirdyashkin ◽  
V. G. Salamatov ◽  
Yu. M. Maksimov ◽  
V. F. Tarasenko ◽  
E. A. Sosnin ◽  
...  
Keyword(s):  
Solid Phase ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Reaction Products ◽  
X Ray ◽  
Condensed Systems
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