Using Hydrophilic Ionic Liquid, [bmim]BF4 – Ethylene Glycol System as a Novel Media for the Rapid Synthesis of Copper Nanoparticles

In this work, we present a novel method for the synthesis of copper nanoparticles. We utilize the charge compensatory effect of ionic liquid [bmim]BF4 in conjunction with ethylene glycol for providing electro-steric stabilization to copper nanoparticles prepared from copper sulphate using hydrazine hydrate as a reducing agent. The formed copper nanoparticles showed extended stability over a period of one year. Copper nanoparticles thus prepared were characterized by powder X-ray diffraction measurements (pXRD), transmission electron microscopy (TEM) and quasi elastic light scattering (QELS) techniques. Powder X-ray diffraction (pXRD) analysis revealed relevant Bragg's reflection for crystal structure of copper. Powder X-ray diffraction plots also revealed no oxidized material of copper nanoparticles. TEM showed nearly uniform distribution of the particles in methanol and confirmed by QELS. Typical applications of copper nanoparticles include uses in conductive films, lubrication and nanofluids. Currently efforts are under way in our laboratory for using these nanoparticles as catalysts for a variety of organic reactions

Localized States Model of GeS2 Glasses Based on Electronic States of GenSm Clusters Calculated by Using TD-DFT Method

The first-principles calculation based on time dependent - density functional theory (TDDFT) reveals the origin of the molecular electronic structure and its connection to the localized states of the g-GeS2(T-i). The band gaps computed for GenSm clusters representing the local structures and their correlation to the experimental band gaps of g-GexS100-x together with possible model of band-tail states of g-GeS2 have been discussed. According to the observed results we propose to consider the band-gap states of g-GexS100-x as superposition of electronic states of GenSm clusters. The type and concentration of these clusters are compositionally-dependent and influenced by technological conditions used for glass preparation

Boson peak in low-frequency Raman spectra of AsxS100-x glasses: nanocluster contribution

The origin of the Boson peak was investigated using Raman spectroscopy and ab initio calculations. Low frequency Raman active vibrational modes of different branchy-, ring- and cage-like AsmSn nanoclusters were calculated and compared to experimentally determined Raman spectra of AsxS100-x glasses with different compositon. A good correlation was found between the spectral features and the calculated Raman modes. The possible structural nature of the Boson peak in arsenic chalcogenides is proposed and discussed

Ab initio and Raman study of medium range ordering in GeSe2 glass

High resolution Raman spectra of GeSe2 glass were measured and fitted using individual Gaussian components. The structural origin of the components were interpreted using the results of ab initio density functional theory calculations performed on GenSem nanoclusters (n = 2-6, 12; m = 6-9, 12, 14-16, 30) which represent the local structure of GeSe2 glass and on some "defect" GenSem clusters that are thought to be related to the inhomogeneity of the structure at the nanoscale. The calculated vibrational properties of GenSem nanoclusters and their couplings with the short- and medium-range order structure formations in GeSe2 glass are analyzed and discussed. (c) 2013 Elsevier B.V. All rights reserved

Видима фотолюмінесценція при кімнатній температурі в g- As2S3 та в стеклах на основі Ge

PL radiation from long term aged fractured surfaces of GeS2-based glasses was assigned to the surface contaminant effect from native oxidized layer, which might have formed in the air. When have been used for PL measuring the freshly fractured surface of g-GeS2(T3V2) all PL peaks which was connected with GeOx species where disappeared in PL spectrum.Фотолюминесцентное излучение которое наблюдалось со скола стекол на основе GeS2 при старении, отнесено к окисной фазе, которая образовалась на поверхности стекол в течении длительного хранения образцов на воздухе. Все ФЛ максимумы, связанные с центрами GeОx, исчезли с фотолюминесцентного спектра, когда фотолюминесцентный спектр был снят со свежесколотой поверхности объемного стекла g-GeS2(T3V2).Фотолюмінесцентне випромінювання, що спостерігалося зі сколу стекол на основі GeS2 при старінні, віднесено до окисної фази, що утворилася на поверхні стекол під час тривалого зберігання зразків на повітрі. Усі ФЛ максимуми пов'язані з центрами GeОx,зникли з фотолюмінесцентного спектру, коли фотолюмінесцентний спектр був знятий зі свіжесколотої поверхні з об'ємного скла g-GeS2(T3V2)