Volume 3, Issue 2, April 2012


Editorial

Editorial

Ashutosh Tiwari

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 64-64
DOI: 10.5185/amlett.2012.2001

We are pleased to publish the 3 volume, 2nd issue, 2012 of Advanced Materials Letters, a quarterly international journal that is intended to provide top-quality peer-reviewed articles in the fascinating field of materials science particularly in the area of structure, synthesis and processing, characterization, advanced-state properties, and applications of materials. The journal publishes review articles, research articles, notes and short communications. The peer-review and proof-ready editing is expected to be completed with-in 3 months and the online version will be published immediately. Advanced Materials Letters is fully committed to publish articles with no page charges and all the published articles are indexed and are available for download for free.

Book Review On Intelligent Nanomaterials

Ingemar Lundstrom

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 65-65
DOI: 10.5185/amlett.2012.2002

I would like to congratulate the Editors for this impressive collection of contributions on the front line of nanomaterial research. The volume covers both fundamental materials science and innovative applications of nanomaterials. The different chapters with their extensive reference lists should serve as extremely good sources for new as well as already established researchers in the area. The whole book or parts of it may also serve as a text for Ph.D. and master courses on nanomaterials. Almost any “intelligent nanomaterial” can be found in the volume and some are described in several of the chapters. Perhaps, I would have expected to find more entrances to graphene, one of the “intelligent nanomaterials” of our time. This little remark cannot blur the fact, however, that Intelligent Nanomaterials, edited by Tiwari, Mishra, Kobayashi and Turner, is an exceptionally valuable reference book for many researchers and students in materials science, nano- and biotechnology.

Influence Of ZnO Buffer Layer On Growth Of Sb Doped ZnO Nano Wires Using Nano Particle Assisted Pulsed Laser Deposition (NAPLD) Using Sb As Catalyst

I.A. Palani; D. Nakamura; K. Okazaki; T. Shimogaki; M. Higashihata; T. Okada

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 66-70
DOI: 10.5185/amlett.2012.1302

Influence of ZnO buffer layer thickness on the structural and optical properties of the Sb catalyzed/doped ZnO nanowires synthesized using NAPLD has been investigated. Buffer layer with a thickness of 100 nm, 800 nm and 1600 nm coated with Sb are used as a substrate and pure ZnO was used as a target to synthesize Sb doped ZnO nanowires. Introduction of the buffer layer lead to the growth of vertically aligned along with horizontally grown ZnO nano wires. With the increase in buffer layer thickness, the core diameter of the vertically grown ZnO nano wires was subsequently increased. Nano wires synthesized with a buffer layer thickness of 1600 nm showed a significant change in the lattice constants, resulting in measurable lower angle of about 0.06º from XRD, widening of lattice fringe spacing of 0.54 nm from TEM and Suppression of A1T and E1(L0) modes in Raman Spectroscopic. In addition a strong UV emission with absence of visible emission was observed from the room temperature PL. This confirms the generation of Sb doped ZnO nano wire with high crystal quality.

Photoelectrochemical Cell Performance Of Chemically Deposited MoBi2Te5 Thin Films

Manauti M. Salunkhe; S. M. Patil; R. M. Mane; S. V. Patil; P. N. Bhosale

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 71-76
DOI: 10.5185/amlett.2012.1304

Molybdenum bismuth telluride thin films have been prepared on clean glass substrate using Arrested Precipitation Technique (APT) which is based on self organized growth process. As deposited MoBi2Te5 thin films were dried in constant temperature oven at 110 o C and further characterized for their optical, structural, morphological, compositional and electrical analysis. Optical absorption spectra recorded in the wavelength range 300-800 nm showed band gap (Eg) 1.44 eV. X-ray diffraction pattern and scanning electron microscopic images showed that MoBi2Te5 thin films were nanocrystalline having rhombohedral structure. The energy dispersive spectroscopic analysis of as deposited thin films showed close agreements in theoretical and experimental atomic percentages of Mo 4+ , Bi 3+ and Te 2- and suggest that the chemical formula MoBi2Te5 assigned to molybdenum bismuth telluride thin film material is confirm. The resistivity and thermoelectric power measurement studies showed that the films were semiconducting with n-type conduction. The fill factor and conversion efficiency (η) are determined by fabricating PEC cell using MoBi2Te5 thin film electrode. In this article we report the optostructural, morphological, compositional and thermoelectric characteristics of nanocrystalline MoBi2Te5 thin films to check its suitability as photoelectrode in PEC Cell.

Aliovalent Yttrium Added Silver Sulphate: A Promising Candidate For SO2 Gas Sensor

S.W. Anwane; R.S. Anwane

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 77-81
DOI: 10.5185/amlett.2012.1314

Optimum alio-valent doping with yttrium sulphate creating 7% vacancy concentration provided promising features from sensor application view. This provides a better option over green Silver Sulphate. The sensors fabricated with the modified sulphate based silver ion conducting solid electrolyte, silver-silver sulphate reference electrode and test gas (Pt) electrodes has been tested over the range of 50-1000 ppm SO2 blended in constant oxygen-partial pressure and argon at 400 o C. A promising sensor characteristic behaviour is exhibited by the modified electrolyte - solid solution of silver sulphate with yttrium.

Solvent Tuned PANI-CNT Composites As advanced Electrode Materials For Supercapacitor application

Ashok K. Sharma; Yashpal Sharma; Rajesh Malhotra; J.K. Sharma

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 82-86
DOI: 10.5185/amlett.2012.1315

Composites of polyaniline and multiwalled carbon nanotube were prepared by in- situ chemical oxidative polymerization of the aniline monomer in 1M HCl and 1M HCl with 20% ethanol as solvent. The PANI-CNT composites were characterized by FTIR and XRD method. The surface morphology characterization of the composites was done by using scanning electron microscopy (SEM). Electrochemical behavior of prepared PANI-CNT composites was investigated by means of cyclic voltammetry. Specific capacitance of PANI-CNT composite using 0.02M aniline in 1M HCl (20% ethanol) and 1M HCl was 597.82 and 484.49 F/g respectively at scan rate of 2mV/s in 1M H2SO4.

Application Of Bismuth-film Modified Glassy Carbon Electrode For Solid-phase Extraction Of Sudan I

Jie Cai; Xiaozhou Zhou; Yuanqiang Tu; Guanwen Feng; Chunyan Huang

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 87-91
DOI: 10.5185/amlett.2011.4237

A sensitive electrochemical sensor for detection of sudan was developed based on solid-phase extraction (SPE) at bismuth-film modified glassy carbon electrode. SPE of sudan may be due to the physical adsorption between sudan and the bismuth film. The properties of the bismuth-film electrode (BiFE) designed for detection Sudan were examined by scanning electron microscopy (SEM), electrochemical impedance and voltammetry. The various bismuth plating solutions containing Cl-, Br- and I- respectively, were tested in bismuth-film generation. It has been found that the plating solution only containing Br- ensures the finest quality bismuth film for analytical purposes. Other operational parameters such as extraction time, pH of the electrolytic and sample solution, and co-solvents have been optimized. Under the optimum experimental conditions, the stripping voltammetric response was proportional to the concentration of sudan ranging from 0.1 to 10 M. The detection limit was 0.05 M.

Nonlinear Ferroelectric And Dielectric Properties Of Bi(Mg0.5Ti0.5)O3-PbTiO3 Perovskite Solid Solutions

Seema Sharma; Radheshyam Rai; D. A. Hall; Judith Shackleton

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 92-96
DOI: 10.5185/amlett.2011.6279

Polycrystalline samples of Bi(Mg0.5Ti0.5)O3-PbTiO3 (BMT-PT) solid solutions exhibit high ferroelectric Curie temperatures and are promising materials for high temperature piezoelectric devices. A morphotropic phase boundary (MPB) between ferroelectric rhombohedral and tetragonal phases occurs between BMT-PT ratio of 70-30 and 65-35 compositions. In the present investigation, ceramics having BMT-PT ratios in the range from 70-30 to 50-50 were prepared by a conventional solid state reaction method. The change of crystal structure as a function of composition and temperature has been studied using high temperature X-ray diffraction. Polarisation-Electric field hysteresis curves at different temperatures show antiferroelectric behaviour for x = 0.30, 0.35 and 0.40 compositions while 0.45 and 0.50 show a ferroelectric behavior.

Dielectric Relaxation And Conductivity Studies Of (K0.5Bi0.5)(Fe0.5Nb0.5)O3 Ceramics

Subhadarsani Sahoo; Dhiren K. Pradhan; R. N. P. Choudhary; B. K. Mathur

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 97-101
DOI: 10.5185/amlett.2011.4250

The polycrystalline sample of (K0.5Bi0.5)(Fe0.5Nb0.5)O3 was synthesized by a high- temperature solid-state reaction technique. The material crystallizes in cubic structure at room temperature. The dielectric properties of the material were investigated in a temperature range from 30-200 ºC in the frequency range (102–107 Hz). Impedance data is well fitted using proper equivalent circuit composed of a parallel resistance and capacitance in series with a parallel resistance, constant phase element and a capacitance. The compound shows a typical negative temperature coefficient of resistance type (NTCR) behavior like that of semiconductors. Modulus spectroscopy and dielectric conductivity formalism were employed to study dielectric relaxation phenomena in the material. The frequency dependence of conductivity is well fitted to Jonscher’s single power law.

Deposition Of PZT Thin Films With (001), (110), and (111) Crystallographic Orientations And Their transverse Piezoelectric Characteristics

D. Ambika; V. Kumar; K. Tomioka; Isaku Kanno

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 102-106
DOI: 10.5185/amlett.2011.7281

Pb(ZrxTi1-x)O3 [PZT] thin films of morphotropic phase boundary (MPB) composition having {001}, {110}, and {111}-orientations were fabricated on silicon substrates (111)Pt/Ti/SiO2/Si using a metal organic decomposition spin-coating technique. The influence of crystallographic orientation on the transverse piezoelectric coefficient e31 * of the films have been determined. The largest e31* was found in {110}-oriented film. The differences observed in e31 * have been explained on the basis of domain wall contributions which are dependent on film texture. The influence of thin film texture on polarization switching characteristics have also been studied.

Ferromagnetism In Inhomogeneous Bulk samples Of Co-doped ZnO

V. K. Sharma; M. Najim; G. D. Varma

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 107-111
DOI: 10.5185/amlett.2011.6276

We report on the effect of different gaseous environments (air, argon and Ar/H2) on the structural and magnetic properties of Zn0.98Co0.02O synthesized by the solid state reaction route. We have also studied the effect of different annealing times and temperatures on the as synthesized samples. M-H curves of the air sintered and the argon annealed samples show paramagnetic behavior whereas the samples annealed in the hydrogenated argon (Ar/H2) environment exhibit ferromagnetic property at room temperature. Based on the structural and magnetic properties it has been found that Co metal clusters are responsible for the observed room temperature ferromagnetism (RTFM) in the hydrogenated samples.

Study Of Surface Morphology And Grain Size Of Irradiated MgO Thin Films

Jitendra Pal Singh; I. Sulania; Jai Prakash; S. Gautam; K. H. Chae; D. Kanjilal; K. Asokan

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 112-117
DOI: 10.5185/amlett.2012.1307

Present work reports 200 MeV Ag 15+ irradiation induced effects on the surface morphology, grain size and local electronic structure in MgO thin films deposited by e-beam evaporation under ultra High vacuum. The grain size was found to decrease from 37 nm (pristine film) to 23 nm for the sample irradiated with fluence of 1×10 12 ions/cm 2 and thereafter it increases upto fluence of 5×10 12 ions/cm 2 . Similar changes with ion fluence were also observed for surface roughness. Shifting and disappearance of peaks in X-ray absorption spectra with irradiation shows the electronic structure modification after irradiation. The detailed analysis of observed results has been done on the basis of existing theories.

Citrate–nitrate Derived Sr0.5Ba0.5Ta2O6 Tetragonal Tungsten Bronze Nanorods: Investigation Of Their Optical And Dielectric Properties

Yogesh Kumar Sharma; Krishna Kumar; Chandrashekhar Sharma; R. Nagarajan

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 118-125
DOI: 10.5185/amlett.2011.6278

First time novel complex strontium barium tantalate, Sr0.5Ba0.5Ta2O6 was successfully synthesized in 1D structure (nanorods) by citrate-nitrate gel route. Their structural properties were examined via X-ray diffractometry (XRD) and revealed the formation of tetragonal tungsten bronze (TTB) structure at as low as 1100ºC. Also, FT-IR, FT-Raman, UV-vis, SEM, TEM and PL were used to identify the structure and properties of powders. Well isolated nanorods of the average diameter of ~200nm can be fabricated by this route. PL spectrum showed strong and broad visible emission band around 439nm due to particles with little surface defects. The frequency dependent dielectric dispersion of SBT50 powders sintered at 1300°C/4 h was investigated in a frequency range from 1 kHz-1MHz and at different temperatures (25°C- 450°C). It is observed that: (i) the dielectric constant (ε') and loss tangent (tan δ) are dependent on frequency, (ii) the temperature of dielectric constant maximum shift toward lower temperature side and the maximum dielectric constant (ε) was observed to be 2400 at 1 kHz. The Tc was found to be ~444-449°C and ferroelectric relaxor or diffuse phase transition like behavior was observed at around 449°C.

Fe Clusters As Origin Of Ferromagnetism In Hydrogenated Zn1-xFexO (x= 0.02 & 0.05) Samples

V. K. Sharma; G.D. Varma

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 126-129
DOI: 10.5185/amlett.2011.7283

Bulk samples of Zn1-xFexO (x=0.02 and 0.05) were synthesized via solid state reaction route by sintering in air at 800 o C. Some sintered samples were annealed in Ar/H2 at 800 o C for ~ 5 hrs. X-ray diffraction results reveal that the basic crystal structure of the as sintered and hydrogenated (Ar/H2) samples corresponds to ZnO wurtzite structure together with some traces of ZnFe2O4 in the as sintered and Fe metal in the hydrogenated samples. The as sintered samples of both compositions show paramagnetic behaviour and after hydrogenation they exhibit ferromagnetic interactions at room temperature. Increase in the electrical conductivity has also been observed in the hydrogenated samples. The presence of small Fe clusters in the hydrogenated samples are expected to be responsible for the observed room temperature ferromagnetism.

Synthesis And Thermal Analysis Of Yttrium Metallorganic Complexes For Evaluation As Chemical Vapor Deposition Precursors

J. Selvakumar; K. S. Nagaraja

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 130-135
DOI: 10.5185/amlett.2011.7293

The thermal stability and suitability of synthesized yttrium metallorganic complexes were studied for chemical vapor deposition use by thermogravimetric analyses. The phase purity of the synthesized complexes was analyzed by powder X-ray diffraction and mass spectral techniques. The equilibrium vapor pressure of screened yttrium complexes was measured over a temperature range 319–475 K using the horizontal thermogravimetric analyzer as a transpiration apparatus. Model and model-free solid-state kinetic methods were applied to non-isothermal and isothermal measurements to derive kinetic characteristics of the sublimation/evaporation process of selected yttrium vapor sources in the conversion range of 0.1 < 0.7. The relevant results are discussed in detail.

Synthesis And Characterization Of Graft copolymers Of Methacrylic Acid Onto Gelatinized potato Starch Using Chromic Acid Initiator In Presence Of Air

Deepak Pathania; Reena Sharma

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 136-142
DOI: 10.5185/amlett.2011.8297

The graft copolymerization of methacrylic acid onto gelatinized potato starch has been carried out at 70 0 C using chromic acid as initiator. The different reaction parameters such as effect of temperature, initiator and monomer concentrations were optimized to determine the maximum percentage grafting. The maximum grafting efficiency of 87.5% was optimized at reaction temperature (60 0 C), monomer concentration (0.81molL -1 ) and initiator concentration (0.02 mmol.L -1 ). The grafted samples were evaluated for other physico-chemical properties such as swelling behavior, moisture absorption and chemical resistance. The grafted samples were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) techniques. The additional peaks observed in FTIR spectra of grafted samples confirmed the grafting of monomer onto gelatinized starch. The grafted co-polymers have been successfully used for the removal metal ions and organic dyes from aqueous system.

A Study Of Structural, Dielectric And Electrical properties of Ba(Nd0.5Nb0.5)O3 Ceramics

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 143-148
DOI: 10.5185/amlett.2011.8298

Dielectric spectroscopy is applied to investigate the electrical properties of a barium neodymium niobate, Ba(Nd0.5Nb0.5)O3 (BNN) in a temperature range from 323 K to 453 K and in the frequency range from 50 Hz to 1 MHz. The X-ray diffraction of the sample at room temperature shows a tetragonal phase. The scanning electron micrograph of the sample shows the average grain size of BNN ~ 1.92 mm. An analysis of the dielectric constant (e ¢) and loss tangent (tand) with frequency is performed assuming a distribution of relaxation times. The low frequency dielectric dispersion corresponds to DC conductivity. The logarithmic angular frequency dependence of loss peak is found to obey an Arrhenius law with activation energy of 0.55 eV. The frequency dependence of electrical data is also analyzed in the framework of conductivity and electric modulus formalisms. Both these formalisms show qualitative similarities in relaxation times. The scaling behavior of tangent loss (tanδ) suggests that the distribution of relaxation times is temperature independent in BNN. 

Synthesis, Characterization And Catalytic Behaviour Of Entrapped Transition Metal Complexes Into The Zeolite-Y

Chetan K. Modi; Parthiv M. Trivedi

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 149-153
DOI: 10.5185/amlett.2011.10313

Zeolites encumbered with transition metal ions are promising heterogeneous catalysts. Knowledge about the location and structure of the metal centers is of paramount importance for the understanding of the catalytic potential of these materials. A series of entrapped transition metal complexes in the nanopores of zeolite-Y of the type [M(EVTCH)2]-Y [where M = Mn(II), Co(II), Ni(II) and Cu(II); ethylvanillin thiophene-2-carboxylic hydrazone (EVTCH)] have been synthesized by Flexible Ligand Method (FLM). These materials have been characterized by various physico-chemical techniques such as ICP-OES, GC-MS, elemental analyses, (FT-IR, 1H- and 13C-NMR and electronic) spectral studies, BET, scanning electron micrographs (SEMs) as well as X-ray diffraction patterns (XRD). The catalytic significance of these materials has been carried out over the liquid-phase hydroxylation of phenol with 30 % H2O2 to give catechol as a major product and hydroquinone as a minor product.

Synthesis Of Nanostructured Iron-antimonate and Its Application In Liquefied Petroleum Gas sensor

Satyendra Singh; B. C. Yadav; Archana Singh; Prabhat K. Dwivedi

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 154-160
DOI: 10.5185/amlett.2011.11318

In this paper we report the synthesis of iron-antimonate (FeSbO4) via co-precipitation method for the LPG sensing application. X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray analysis (EDAX) were used to confirm the crystal structure, crystallite size, surface morphology and elemental composition of the sensing material. Our XRD results confirm the single phase formation with tetragonal crystal structure of the synthesized material. Extremely broad reflections were observed indicating nanosized particle nature of the material obtained. The estimated value of average crystallite size was found 3 nm. Optical characterizations were done using UV-visible spectrophotometer and the value of energy band gap was found 3.8 eV by Tauc plot. Fine powder resulted from the chemical co-precipitation reaction was used to prepare the LPG sensing element in the form of pellet. The average sensor response of the FeSbO4 pellet was 2.2. LPG sensor based on iron-antimonate shows 97% reproducibility after one month, which illustrates the stability of the fabricated sensor. Electrical properties of iron-antimonate in air were also investigated. 

Synthesis And Characterization Of Linear polylactic Acid-based Urethanes Using Tin modified Solid Cloisite-30B Catalyst

Balaji S. Selukar; Sharad P. Parwe; Kavita K. Mohite; Baijayantimala Garnaik

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 161-171
DOI: 10.5185/amlett.2011.11325

In recent year, biocompatible, biodegradable materials (linear polylactic acid-based urethanes) in the solid and/or liquid form have attracted tremendous attention in biomedical application particularly in stent coating. Low molecular weight poly (lactic acid) s (PLA), having narrow molecular weight distribution was by dehydropolycondensation method using tetraphenyltin as a catalyst. Hydroxyl terminated linear polylactic acid was prepared reacting PLA with aliphatic diol compounds. The hydroxyl end groups were determined by 31P NMR. PLA oligomers containing both hydroxyl and carboxylic groups were also synthesized by the ring opening polymerization using stannous octoate as an initiator and water as a coinitiator and their structures were confirmed by spectral techniques. The tin modified solid cloisite-30B catalyst was prepared and characterized. The reaction of PLA oligomers and isocyanates (4,4’ methylene bis (phenyldiisocyanate), toluenediisocyanate, 4,4’ methylenebis (cyclohexyldiisocyanate), hexamethylene diisocyanate) was carried out using tin modified solid cloisite-30B catalyst. The effect of the reaction conditions, i.e. the reaction temperature, molar ratio, isocyanates and catalyst on the molecular weight were explored. The structure of the ploymer samples was determined with FT IR, 1H NMR, 13C NMR, matrix-assisted laser-desorption ionization time-of-flight mass spectroscopy (MALDI– TOF MS) and TEM. The present work will highlight the synthesis and characterization of various linear polylactic acid-based urethanes using tin modified solid cloisite catalyst.

Fascinating World Of Immerging Graphene Technologies

Atul Tiwari

Advanced Materials Letters, 2012, Volume 3, Issue 2, Pages 172-173
DOI: 10.5185/amlett.2012.2003

After decades, allots of research to exploit the unique properties of graphite resulted to a successful discovery of a new nano material called graphene. Unprecedented efforts by two Manchester University professors resulted in an extraction of a single layer of graphite in the year 2004 that earned them a Nobel Prize of physics in 2010. Several terms that are interrelated to graphene such as graphite nano platelets, graphite oxide, single layer or few layers of graphite oxide, graphene oxide, functionalized graphene sheets or functionalized nano graphene sheets, exfoliated graphene oxide and their numerous processing techniques have appeared in the last few years.