Superlattices of Semiconductor Quantum Size Particles in Layered Organic Acids

1999 ◽  
Vol 576 ◽  
Author(s):  
Ronit Popovitz-Biro ◽  
Shouwu Guo ◽  
Volker Hensel ◽  
Edna Shavit ◽  
Meir Lahav
Keyword(s):  
Organic Acids ◽  
Hydrocarbon Chain ◽  
Benzoic Acids ◽  
X Ray ◽  
Quantum Size ◽  
Transmission Electron ◽  
Layer Structures ◽  
Organic Matrices ◽  
Derivatives Of ◽  
Long Chain

ABSTRACTThe preparation of lead sulfide and cadmium sulfide quantum size particles arranged in periodic layers within organic matrices is described. Superlattices of the particles have been generated in crystals or thin films of long chain amphiphilic acids by topotactic gas-solid reactions of the lead or cadmium salts, that pack in layer structures, with H2S gas. X-ray powder diffraction and transmission electron microscopy reveal that the crystalline order of the reactant has been partially retained in the organic-inorganic composite. This approach is demonstrated by examples of organic acids bearing an aromatic ring along the hydrocarbon chain, such as derivatives of phenyl propionic and benzoic acids.

Grafted organic derivatives of kaolinite: I. Synthesis, chemical and rheological characterization

Clay Minerals ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 537-546 ◽  
Author(s):  
J. E. F. C. Gardolinski ◽  
G. Lagaly
Keyword(s):  
Alkyl Chain ◽  
Hydroxyl Groups ◽  
Rheological Characterization ◽  
Aqueous Dispersions ◽  
X Ray ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Transmission Electron ◽  
Yield Value ◽  
Derivatives Of

AbstractSeveral new interlayer-grafted derivatives of kaolinite were synthesized by esterification of inner-surface hydroxyl groups with alkanols, diols and glycol mono-ethers starting with the dimethyl sulphoxide intercalate. The derivatives were characterized by X-ray powder diffractometry, thermal analysis, Fourier transform infrared spectroscopy and transmission electron microscopy. The grafted molecules are arranged in monolayers between the kaolinite layers, with typical basal spacings of ~11.3 Å. Rheological studies of aqueous dispersions of the modified kaolinites revealed an exponential increase of the yield value and apparent viscosity with increasing alkyl chain length of the grafted molecules.

Ultrasonically Assisted Synthesis of Tin Sulfide Nanorods at Room Temperature

2009 ◽  
Vol 79-82 ◽  
pp. 313-316 ◽  
Author(s):  
Jun Pan ◽  
Jiang Ying Li ◽  
Sheng Lin Xiong ◽  
Yi Tai Qian
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ultrasonic Method ◽  
Band Gaps ◽  
Tin Sulfide ◽  
X Ray ◽  
Lattice Constants ◽  
Quantum Size ◽  
Tin Chloride ◽  
Transmission Electron ◽  
Standard Card

A simple ultrasonic method was developed to synthesize rod-like SnS nanocrystals, using tin chloride and thioacetamide as starting materials, ethanolamine and water as solvents. The as-obtained nanostructures were characterized by X-ray diffraction (XRD) study, energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Ultraviolet-visible spectrophotometry (UV). From the XRD pattern, the reflection peaks of the as-obtained samples can be indexed to the orthorhombic structure with lattice constants a = 3.99, b = 4.34, c = 11.20 Å , which are very consistent with the values in the standard card of SnS phase (JCPDS No. 39-0354). No characteristic peak was observed for other impurities such as SnO2 and SnS2, implying the formation of single-phase tin monosulfide. The quantification calculation shows the ratio of Sn/S to be 51.30/48.70 via the EDS analysis. These data clearly indicate that the as-prepared rod-like nanostructures are exactly SnS. TEM results show that, the SnS nanorods have length about 100nm and width less than 30nm. The direct and indirect band gaps of the SnS nanorods are determined to be 1.53 eV and 1.34 eV, respectively. The band gaps of the as-obtained SnS nanorods showed blue shifts due to the quantum size effects. The ultrasonic condition is believed to be critical for the formation of SnS with pure phase. For it provides the energy to form rod-like nanostructures and helps preventing the hydrolysis of Sn2+ to form tin oxides and hydrates. Also, it prevents oxidation of the final products.

scholarly journals EFFECT OF LONG-CHAIN ALKYLAMINE ON THE DISPERSIBILITY AND TRIBOLOGICAL PROPERTIES OF ALKYL-GRAPHENE IN LUBRICANT OIL

2018 ◽  
Vol 56 (2A) ◽  
pp. 163-173 ◽  
Author(s):  
Nguyen Huu Van
Keyword(s):  
Electron Microscopy ◽  
Alkyl Chain ◽  
X Ray Diffraction ◽  
X Ray ◽  
Lubricant Oil ◽  
Transmission Electron ◽  
Lubrication Oil ◽  
Carboxylic Groups ◽  
Chain Lengths ◽  
Long Chain

We report on the preparation of Alkyl-Graphene by hydrothermal method, and their dispersion in lubrication oil. The alkylated graphenes with variable alkyl chain lengths (Cn = 8, 12, 18) are prepared by coupling of alkylamine with carboxylic groups of graphene oxide (GO). FTIR, XPS, TGA methods were used to analyze and assess the GO modified ability by amine. The morphology and microstructure of prepared GO and alkyl-graphene were examined using field emission scanning electron microscopy (FESEM), transmission electron microscopy (HRTEM), X-ray diffraction (XRD). The experiments confirmed the formation of GO and alkyl-graphene. Stably distributed system of alkyl-graphene in SN500 reached 13.2 g/l with octylamine and 9.5 g/l with decylamine and 6.0 g/l with dodecylamine. The lubricating characteristics of lubrication oil containing alkyl-graphene was determined according to ASTM D2783. Evaluation of the reduction performance of SN500 oil when adding with alkyl-graphene: modified GO by octylamine gave the best performance compared to decylamine, dodecylamine. The reduction of abrasion reached 11.3 % at 0.3 g/l and 12.5% at 0.4 g/l of octyl-graphene.

Mbe Growth of Strained-Layer InSb/InAlSb Structures

1990 ◽  
Vol 198 ◽  
Author(s):  
C.R. Whitehouse ◽  
C.F. Mcconville ◽  
G.M. Williams ◽  
A.G. Cullis ◽  
S.J. Barnett ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Critical Thickness ◽  
Multiple Quantum ◽  
Material System ◽  
X Ray Diffraction ◽  
Mbe Growth ◽  
X Ray ◽  
Strained Layer ◽  
Transmission Electron ◽  
Layer Structures

ABSTRACTThe MBE growth and related materials characterisation of InSb/InAlSb strained-layer structures is described. Band-gap considerations and critical thickness calculations are presented and indicate that this material system should offer considerable device potential. Detailed structural studies, performed using both transmission electron microscopy and X-ray diffraction, confirm the growth of high quality multiple quantum-wells, and 2K photoluminescence has shown corresponding energy upshifted transitions.

Microstructure - Stress - Property Relationships in Nanometer Ge/C Multilayers

1994 ◽  
Vol 343 ◽  
Author(s):  
Xiang Lu ◽  
Tai D. Nguyen ◽  
James H. Underwood
Keyword(s):  
Stress Measurement ◽  
Measurement Techniques ◽  
Normal Incidence ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Evolution Path ◽  
Layer Structures ◽  
Potential Applications ◽  
Ray Scattering

ABSTRACTA series of sputtered as-prepared and annealed Ge/C multilayer structures with periods ranging from 2 to 8 nm has been studied with high resolution transmission electron microscopy (HRTEM), x-ray scattering, and stress measurement techniques. Ge/C multilayers have potential applications as normal incidence reflective mirrors near 4.4 nm wavelength. The reflectivity and stress in these structures depend on the microstructural evolution of the component layers. The as-prepared structure of both Ge and C layers appear amorphous from TEM imaging and diffraction. Annealing at 500°C for 60 minutes leads to crystallization of the Ge layers. As the phase diagram indicates, no carbide compound has been found. X-ray scattering reveals that the multilayer period expands by as much as 10% after annealing. Both TEM images and x-ray profiles suggest that the layer structures remain well-defined upon annealing. In-situ stress-temperature measurements directly show the Ge/C multilayer microstructure evolution path. X-ray measurements show that the structures with periods near 2 nm undergo a significant improvement on optical performance with annealing. The physical mechanisms that may have caused the optical enhancement are discussed. Correlation of the stress evolution in the multilayers and in individual layers during annealing, and their relationships to the microstructures and optical properties are examined.

Identification of vermiculite by transmission electron microscopy and X-ray diffraction

Clay Minerals ◽  
1992 ◽  
Vol 27 (2) ◽  
pp. 185-192 ◽  
Author(s):  
H. Vali ◽  
R. Hesse
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Natural Sample ◽  
X Ray Diffraction ◽  
X Ray ◽  
Stacking Order ◽  
Transmission Electron ◽  
Layer Structures ◽  
Ultrathin Sections ◽  
K Depletion

AbstractThe expandability of K-depleted biotite and natural vermiculite was studied using transmission electron microscopy (TEM) and X-ray diffraction (XRD). K-depletion in layer-silicates was achieved by treating ultrathin sections with 0·1 m CaCl2 and BaCl2 solutions. The natural sample of biotite, which by XRD revealed no expandability on ethylene glycol or glycerol solvation, displayed 10–15% expanded layers when viewed by TEM after alkylammonium intercalation. The proportion of expanded layers increased after CaCl2 treatment. XRD of vermiculite samples revealed two sets of expandable interlayers after alkylammonium treatment, corresponding to two types of particles with different layer structures observed by TEM. Identification of vermiculite by TEM based on basal spacings is reliable with alkylammonium treatment. Intercalation of alkylammonium ions into the interlayers of vermiculite improved the degree of stacking order of the 2:1 layers.

scholarly journals Green Synthesis of New Category of Pyrano[3,2-c]Chromene-Diones Catalyzed by Nanocomposite as Fe3O4@SiO2-Propyl Covalented Dapsone-Copper Complex

2021 ◽  
Vol 9 ◽  
Author(s):  
Leila Zare Fekri
Keyword(s):  
Reaction Times ◽  
Aromatic Aldehydes ◽  
Green Solvent ◽  
X Ray Diffraction ◽  
Multicomponent Synthesis ◽  
X Ray ◽  
High Productivity ◽  
Transmission Electron ◽  
Ft Ir ◽  
Derivatives Of

Nanomagnetic dapsone-Cu supported on the silica-coated Fe3O4 (Fe3O4@SiO2-pr@dapsone-Cu) nanocomposite was synthesized and characterized by Fourier transform infrared (FT-IR), energy-dispersive X-ray (EDX), X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), zeta potential, vibrating sample magnetometer (VSM), and thermogravimetric analysis (TGA). This newly synthesized nanocomposite was chosen to act as a green, efficient, and recyclable Lewis acid for the multicomponent synthesis of new derivatives of pyrano[3,2-c]chromene-diones through the reaction of aromatic aldehydes, indandione, and 4-hydroxycoumarin in water. All of the synthesized compounds are new and are recognized by FT-IR, NMR, and elemental analysis; this avenue is new and has advantages such as short reaction times, high productivity, economical synthesis, and use of green solvent, H2O, as a medium. The catalyst is magnetically recoverable and can be used after six runs without a decrease in the efficiency.

PbSe Nanocrystals Synthesized by an Ultrasonic Electrochemical Method

2011 ◽  
Vol 194-196 ◽  
pp. 545-548
Author(s):  
Wen Ran Feng ◽  
Hai Zhou
Keyword(s):  
Electrochemical Method ◽  
Sodium Citrate ◽  
Energy Gap ◽  
Slenderness Ratio ◽  
X Ray ◽  
Quantum Size ◽  
Transmission Electron ◽  
Visible Spectra ◽  
Uv Visible ◽  
20 Nm

Lead selenide (PbSe) is quite an important semiconductor material with several superior physical properties, e.g. optical and electrical ones. In this paper, PbSe nanocrystals (NCs) with different morphologies such as sphere, rod and hexagon were successfully prepared by an ultrasonic electrochemical method, using sodium citrate as the coordination agent, at room temperature. The crystal structure and the morphology of the as-prepared PbSe NCs were confirmed by means of the Transmission Electron Microscopy (TEM) and X-ray diffractometer (XRD). The ultraviolet-visible Spectrophotometer (UV) was performed to analyze the optical properties of the PbSe NCs. Results show that the nanospheres were about 60 nm in diameter, and the nanorods were 20 nm in diameter with a slenderness ratio of 25. The possible mechanism for the nanorods growth was discussed. The energy gap of the PbSe NCs deduced from the UV-visible spectra was much larger than their bulk counterparts, due to the quantum size effect.

Microstructures and interdiffusions of Pt/Ti electrodes with respect to annealing in the oxygen ambient

1995 ◽  
Vol 10 (7) ◽  
pp. 1790-1794 ◽  
Author(s):  
Kyu Ho Park ◽  
Cha Yeon Kim ◽  
Young Woo Jeong ◽  
Hyun Ja Kwon ◽  
Kwang Young Kim ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Electron Spectroscopy ◽  
Auger Electron ◽  
Annealed Sample ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Layer Structures ◽  
Degree Of Oxidation ◽  
Increasing Temperature

The microstructural variation and the interdiffusion of Pt (80 nm)/Ti (70 nm)/SiO2/Si during annealing in O2 were investigated using Auger electron spectroscopy, x-ray diffraction, transmission electron microscopy, and scanning electron microscopy. While the as-deposited and 400 °C annealed samples showed well-defined layer structures without any significant interfacial reaction, the degree of oxidation remarkably increased with increasing temperature above 500 °C. The PtTi alloy phase with Pmma structure (AuCd type) was observed from the 500 °C annealed sample. Drastic interdiffusion occurring above 600 °C changed the Pt/Ti bilayer into a very entangled structure. Some TiO2 phases were exposed to the ambient between Pt hillocks. In addition, a small amount of Pt-silicide was found near the TiOx/SiO2 interface.

The Microstructure Evolution of Corrosion Phenomenon on Aluminum Bond Pads

2005 ◽  
Author(s):  
Jian-Shing Luo ◽  
Hui-Min Lo ◽  
Jeremy D. Russell
Keyword(s):  
Electron Microscopy ◽  
Microstructure Evolution ◽  
Photoelectron Spectroscopy ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
X Ray ◽  
Nano Crystalline ◽  
Transmission Electron ◽  
Layer Structures ◽  
Bond Pads

Abstract X-ray photoelectron spectroscopy (XPS) is a very popular tool for identification of the chemical state of fluorine contamination on aluminum (Al) bond pads. To date, as far as the authors are aware the detailed microstructures of fluorine corrosion on bond pads have not been reported. This paper reports the microstructure evolution of fluorine corrosion on bond pads in a plastic box under specific environment conditions by using transmission electron microscopy (TEM), optical microscopy, focused ion beam and scanning electron microscopy (SEM). The elemental distributions and chemical bonding were performed by using Gatan Image Filter/TEM, energy dispersive X-ray/Scanning TEM (STEM), Auger electron spectroscopy and XPS, respectively. On Al pads with 35 atomic %, fluorine residual, corrosion was observed after around 10 days of storage and became more severe with time. The corrosion layers consist of nano-crystalline and amorphous for both single and double-layer structures.

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