Volume 6, Issue 5, May 2015

 Advanced Materials World Congress, Sweden

Ashutosh Tiwari

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 370-370
DOI: 10.5185/amlett.2014.8001

Dear Reader, We are pleased to announce next Advanced Materials World Congress (AMWC), 23-26 August, 2015, www.vbripress.com/amwc. It is a four-day international event organised by the International Association of Advanced Materials and sponsored by the VBRI Press, which usually meets every two-year. The upcoming world congress is going to host in the city of Nobel Prize, Stockholm, Sweden. The venue of congress will be on the floor of Baltic Sea from Stockholm-Mariehamn-Stockholm via the Viking Cinderella. The goal of congress is to provide a global platform for researchers and engineers coming from academia and industry to present their research results and activities in the field of fundamental and interdisciplinary research of materials science. The World Congress will provide opportunities for the delegates to exchange their face-to-face novel ideas and experiences with the international experts during the plenary and invited talks, oral presentations and poster sessions. We will also set up sessions with keynote forum, panel discussion and project negotiation. Important dates: • Abstract submission start: 10 July 2014 • Deadline of abstract submission: 15 December 2014 • Confirmation of abstract acceptation: 25 February 2015 • Registration starts: 15 January 2015 • Early bird registration closed: 30 April 2015

Effect Of Substrate Temperature On Nanocrystalline CeO2 Thin Films Deposited On Si Substrate By RF Magnetron Sputtering

Preetam Singh; K. M. K. Srivatsa;Sourav Das

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 371-376
DOI: 10.5185/amlett.2015.5777

Single oriented nanocrystalline CeO2 thin films have been deposited over Si (100) substrate by RF magnetron sputtering in the temperature range 600-700 o C, using CeO2 target. X-ray diffraction pattern for the as deposited CeO2 film at 700 o C shows the dominant (111) orientation with corresponding FWHM value of 0.378 o and the crystallite size 21.50 nm. The refractive index and the optical band gap both were found to increase from 2.35 to 2.66 and 3.25 to 3.43 eV, respectively with increasing substrate temperature. Atomic force microscopy results reveal highly smooth surface of the deposited films with surface roughness below 1.15 nm for the entire range of deposition temperatures. Further, the contact angle measurements on the as deposited CeO2 films showed variation from 122.36 to 81.67 o with respect to the substrate temperature, transforming the wetting property from hydrophobic to hydrophilic in nature. These results indicate the possibility of producing CeO2 films with varying properties for various device applications simply by controlling the substrate temperature.

 Fabrication And Plasmonic Characterization Of Au Nanowires With Controlled Surface Morphology

Ina Schubert; Wilfried Sigle; Loic Burr; Peter A. van Aken; Christina Trautmann; Maria Eugenia Toimil-Molares

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 377-382
DOI: 10.5185/amlett.2015.5721

Gold nanowires are attracting great attention due to their ability to sustain surface plasmons and are thus promising candidates for sensing applications such as surface enhanced Raman and infrared spectroscopy. Controlling all nanowire parameters is crucial to adjust the resonance wavelengths and to obtain high electric field enhancements. We have fabricated Au nanowires with controlled dimensions and surface morphology by electro-deposition of Au and Au-Ag nanowires in the pores of ion-track-etched polymer templates. Smooth and rough nanowires are fabricated by the use of different polymer types. By dealloying of Au-Ag wires, porous Au wires are being created. In addition, we have analyzed the surface plasmonic properties of smooth and porous Au nanowires by scanning transmission electron microscopy combined with electron energy-loss spectroscopy. Our results reveal the excitation of five different longitudinal modes in the smooth as well as in the porous Au wire. The resonance energies of the porous wire are red-shifted compared to the energies of a smooth Au wire with same dimensions, which demonstrates that the surface morphology of the nanowire is an important parameter to tune the multipole surface plasmon modes to specific energies. Knowledge on the plasmonic properties of nanowires dependent on their surface morphology is indispensable for their efficient application for sensor technology.

Tuning Of Optical Properties Of Glass By Embedding Silver Nanoparticles

Annu Sharma; Jyoti Rozra; Isha Saini

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 383-390
DOI: 10.5185/amlett.2015.5649

In the present work, effects of annealing temperature on structural and optical properties of silver-glass nanocomposites synthesized by the combined use of ion-exchange and subsequent thermal annealing in air have been investigated using Transmission electron microscopy (TEM), UV–Visible absorption spectroscopy and Photoluminescence spectroscopy. The appearance of SPR peak characteristic of silver nanoparticle formation around 429 nm in absorption spectra of silver-glass nanocomposite samples indicates towards the formation of silver nanoparticles in glass. The size of silver nanoparticles has been found to increase with increase in annealing temperature. At an annealing temperature of 200°C the size of silver nanoparticles comes out to be 2.31 nm which increases to a value of 7.60 nm at an annealing temperature of 550°C. TEM investigation indicates that silver nanoparticles of size 6.57+1.14 nm are formed in glass matrix. UV-visible absorption and reflection data has been analyzed to ascertain optical properties such as absorption coefficient (α), refractive index (n) and dielectric constant (ε). Emissions bands in the photoluminescence spectra were analyzed to investigate different oxidation states of silver present in the prepared nanocomposite samples. Formation of Ago atoms from Ag + ions are responsible for the quenching of photoluminescence intensity at higher temperature. Such nanocomposites are expected to be promising materials for ultrafast optical switches and for sensing applications.

How Ethanol Treatment Affects The Physico-chemical And Biological Characteristics Of Silk Fibroin Nanofibrous Scaffolds

Mazaher Gholipourmalekabadi; Masoud Mozafari; Mojgan Bandehpour; Marzieh Sameni; Hossein Ghanbarian

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 391-394
DOI: 10.5185/amlett.2015.5739

In this study, the effects of ethanol treatment on the mechanical and biological characteristics of the nanofibrous silk fibroin (NSF) scaffolds were evaluated. The results obtained from the mechanical tests confirmed that ethanol treatment significantly enhanced the physical properties of the scaffolds through the formation of a ß-sheet structure. It was shown that the ethanol treatment increased the mechanical property and cell viability, while decreased the porosity of the randomly arranged uniform nanofibers. The ultimate tensile strength for the NSF and ethanol-treated NSF (ET-NSF) scaffolds were 0.76 and 1.33 MPa, respectively. In addition, the ethanol treatment positively affected the proliferation rate of rat bone-marrow stromal cells (rBMSCs) without any detectable cytotoxicity. All the results obtained from this study strongly indicated the efficacy of ethanol treatment in enhancement of mechanical and biological characteristics of silk fibroin nanofibrous scaffolds.

Characterisation And Dielectric Property Analysis  of A-site Doped LaTiO3-δ Perovskites Synthesised by Ball Milling Method

Bradha Madhavan; Anuradha Ashok

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 395-401
DOI: 10.5185/amlett.2015.5827

The present work highlights a series of perovskites La0.8A0.2TiO3-δ, (where A= Ba, Ca, Sr), which includes a high dielectric constant, a low dielectric loss over a wide temperature, in a frequency range of 30 MHZ. Undoped and A-site doped LaTiO3-δ (with Ba 2+ , Sr 2+ and Ca 2+ ) perovskites were synthesised by solid state reaction method (ball milling). The perovskite phase formation of the milled precursor powders under thermal treatments was investigated by thermogravimetry/differential scanning calorimetry (TG/DSC). Structural analysis of the phase pure sintered pellets revealed an orthorhombic crystal structure for all perovskites. Surface morphology of the sintered pellets exposed the presence of nanosized grains. The oxidation states of La 3+ and Ti 3+ ions have been confirmed using X-ray Photoelectron Spectroscopy (XPS). The dielectric spectral analysis reveals that dielectric properties of the perovskites depend on temperature and frequency. Among the dopants Sr is found to be the most effective in increasing the dielectric properties of LaTiO3-δ. This makes it suitable as a high dielectric material for making capacitors operating at higher frequencies.

 Surface And Thermoluminescence Study Of Dy3+ Doped Sr3B2O6 Nanocrystalline Phosphor

Vinay Kumar; Jitendra Sharma; O.M. Ntwaeaborwa; H.C. Swart

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 402-406
DOI: 10.5185/amlett.2015.5868

In this letter, the thermoluminescence response and surface properties of Sr3B2O6:Dy 3+ nanophosphor prepared by combustion method exposed to γ–rays are reported. The crystalline structure of nanophosphors was confirmed by X-ray powder diffraction. The result indicates rhombohedral nanocrystalline structure with an average grain size of 41 nm. The microstructure and morphology were studied by transmission electron microscopy, which show nanowire like structure with an average diameter of 42 nm. The samples were irradiated with a γ-dose using 60Co source in the range of 100 Gy - 5000 Gy. The kinetic parameter such as activation energy (E), order of kinetics (b), and frequency factor (s) of the main glow peaks of the Sr3B2O6:Dy 3+ sample at 5000 Gy and different heating rates were determined using both the TLAnal program and Chen’s method. The effect of different heating rate at a fixed dose is discussed. X-ray photoelectron spectroscopy was used to study the surface chemical composition and the electronic states.

Development Of Lysine Biosensor Based On Core Shell Magnetic Nanoparticle And Multiwalled Carbon nanotube Composite

Jagriti Narang; Utkarsh Jain; Nitesh Malhotra; Sandeep Singh; Nidhi Chauhan

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 407-413
DOI: 10.5185/amlett.2015.5735

An amperometric lysine biosensor was fabricated by immobilizing lysine oxidase onto core shell magnetic nanoparticles (Core–shell MNPs)/multiwalled carbon nanotube (MWCNT) layer deposited on Au electrode via carbodiimide linkage. Transmission electron microscopy (TEM) for core–shell MNPs, scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and Fourier transform impedance spectroscopy (FTIR) studies were used to characterize the modified electrode. Sensor showed optimal response within 2s at 30ºC in 0.05 M sodium phosphate buffer pH 6.0 when polarized at +0.2 V vs. Ag/AgCl. Linear working range of the biosensor was determined by 0.05 -700 μM with a detection limit of 0.05 μM. A good correlation (r = 0.98) was obtained between serum lysine levels measured by the standard HPLC method (y) and the present method (x). A number of serum substances had practically no interference. The sensor was used in 150 assays and had a storage life of 180 days at 4 o C. This nanohybrid biosensor will be useful for detection of lysine in food and pharmaceutical industries.

Oxidative Synthesis And Electrochemical Studies Of Poly(aniline-co-pyrrole)-hybrid Carbon Nanostructured Composite Electrode Materials For Supercapacitor

Ashok Kumar Sharma; Preetam Bhardwaj; Sundeep Kumar Dhawan; Yashpal Sharma

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 414-420
DOI: 10.5185/amlett.2015.5690

A novel study on conducting polymers based composites involving hybrid carbon nanostructure assemblage of graphene, amine functionalized multiwalled carbon nanotubes and poly(aniline-co-pyrrole) has been done. The composites were synthesized by oxidative polymerization of 1:1 mixture of aniline and pyrrole monomer with ammonium per sulphate and ferric chloride oxidants. UV-vis Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR) and Raman Spectroscopy were used to identify the chemical structure of the obtained composites. Thermal studies indicate that the composites are stable in comparison to poly (aniline-co-pyrrole) alone showing that the hybrid carbon assemblage contributes towards thermal stability in the composites. Crystalline properties of the composites were investigated by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was used to characterize the surface morphology of the composites. The specific capacitance of the composites was characterized by cyclic voltammogram (CV). The capacitive studies reveal that the composite has synergistic effect and highest specific capacitance of 337.35F/g at scan rate of 10mV/sec and 193.06F/g at scan rate of 50 mV/sec was obtained for the composite having thinnest layer of co-polymer over hybrid carbon assemblage i.e., 02-PANI-co-PPY-C.

Inverted Ternary Bulk Hetrojunction Hybrid Photovoltaic Device Based On AgInSe2 –polymer Blend As Absorber And PEDOT: PSS As Hole Transport Layer

Dinesh Pathak; Tomas Wagner; Tham Adhikari; J.M. Nunzi

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 421-424
DOI: 10.5185/amlett.2015.5781

For the first time Inverted ternary bulk hetrojunction hybrid photovoltaic device based on AgInSe2 – polymer blend as absorber and PEDOT:PSS as hole transport layer was fabricated and characterized. Blends of MDMOPVV.PCBM.AIS (MDMOPVV-Poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene], PCBM-(Phenyl-C61-butyric acid methyl ester), AIS-AgInSe2) used as absorber layer. Bulk hetrojuction hybrid Photovoltaic device Ag/PEDOT:PSS /MDPVV.PCBM.AIS/ZnO/ITO was fabricated and tested with standard solar simulator and device characterization system as inverted cell configuration. The best performance and photovoltaic parameters, were obtained using an open-circuit voltage of about Voc 0.24 V, a photocurrent of Jsc 0.56 JSC (mA/cm 2 ), 28.4 (%) FF and an efficiency of 0.038 percent with a white light illumination intensity of 100 mW/cm 2 . Further improvement efforts for better performance are on the way. Successful fabrication and working of this inverted device suggest further optimizations like spinning rate/thickness/solvents/depositions rates for active layers and proceeding further in light of knowledge of recombination studies and molecular modeling of AIS nanopowder with this organic system for better performance of a bulk hetrojunction hybrid solar cell.

 Optical Properties Of Ion Exchanged And Swift Heavy Ion Beam Treated Silicate Glasses

Ranjana S. Varma; D.C. Kothari; A.K. Mallik; A. Bhatnagar; D. Kanjilal; S. Santra; R.G. Thomas; R. Tewari; S. Neogy; G.K. Dey

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 425-431
DOI: 10.5185/amlett.2015.5724

Silver ion exchanges on silicate glasses were carried out at different temperatures 320 °C, 400 °C, and 500 °C for 60 min. The exchanged glasses were either annealed at 500 °C for 60 min or swift heavy ion (SHI) irradiated using 120 MeV Ag 9+ ions at a fluence of 5 x 10 12 ions/cm 2 . Silver nanoparticles were formed in the samples ion exchanged at 500 °C without any post-exchange treatments. Post-exchange annealing treatment resulted in silver nanoparticle formation for samples ion exchanged at temperature of 320 °C and 400 °C. Whereas post irradiation treatment for ion exchanged sample at 320 °C resulted in Ag4 nanocluster formation. After post-irradiation, the density of Ag nanoparticles increases for the sample ion exchanged at temperature of 500 °C. RBS was used to obtain silver depth profiles in the ion exchanged samples. Near surface accumulation of Ag atoms is observed in the RBS spectra for the samples prepared at high ion exchange temperature of 500 °C or SHI irradiated samples, in which Ag nanoparticle formation was also observed. UV-vis absorption spectroscopy and Transmission Electron Microscopy (TEM) were used to obtain signatures of nano-particles and to estimate their size. The ion exchanged glasses without nanoparticles were characterized for their possible use in multimode planar waveguides. The post-exchange treated glasses lost their waveguide property, but exhibited nonlinear optical property indicating their potential use for optical switching. Open aperture z-scan measurements for the sample prepared at high ion exchange temperature of 500 °C shows optical limiting behavior, whereas the samples prepared at low ion exchange temperature followed by annealing or irradiation show saturation behavior.

Noval Approach For Synthesis Sulfur (S-NPs) Nanoparticles Using Albizia Julibrissin Fruits Extract

Akl M. Awwad; Nidá M. Salem; Amany O. Abdeen

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 432-435
DOI: 10.5185/amlett.2015.5792

Sulfur nanoparticles have been successfully prepared from sodium thiosulfate in the presence of Albizia julibrissin fruits extract at room temperature. The resulting sulfur nanoparticles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). XRD characterizes the final product as highly crystalline sulfur, exhibited high purity, spherical shape with average particle size of about 20 nm, and particle size distribution in range 10 nm to 100 nm. The particle size of nanoparticles could be controlled by tuning the amount of Albizia julibrissin fruits extract. FT-IR analysis of S-NPs indicated a new chemistry linkage on the surface of sulfur nanoparticles. This suggests that Albizia julibrissin fruits extract can bind to sulfur nanoparticles through carbonyl of the amino acid residues in the protein of the extracts, therefore acting as stabilizer and dispersing agent for synthesized sulfur nanoparticles. This research provides a greener and more environment-friendly synthetic method for the production of sulfur nanoparticles for antibacterial and antifungal activities.

Growth And Characterization Of Large Grained Poly-Si Films Grown On Biaxially Textured Ni-W Substrate By Hot-wire CVD

Preetam Singh; K. M. K. Srivatsa; Sourav Das

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 436-441
DOI: 10.5185/amlett.2015.5754

Polycrystalline Si (Poly-Si) film with highly crystalline nature, and having most of the grains in the range of 50-100 µm has been grown over biaxially textured Ni-W substrate by Hot-wire chemical vapor deposition technique, using a single buffer layer of CeO2 thin film. This result has been achieved for the SiH4 source gas diluted to 95% with added H2 gas, and for the substrate temperature of 840±10oC and a deposition pressure of 40 mTorr. XRD analysis shows that the Poly-Si films have grown with (111) and (200) orientations. Raman studies reveal that a crystalline volume fraction of 95.3% has been achieved. The imaginary part of pseudo dielectric function, <ε2>, as extracted from ellipsometric data, shows two prominent shoulders at energy positions 3.4 eV and 4.2 eV corresponding to the optical absorption of crystalline Si, indicating a high crystallinity of the Poly-Si film. SEM micrograph shows that the grown Poly-Si film is following the morphology and grain size as that of biaxially textured Ni-W substrate. SIMS analysis of the total multilayer structure shows a formation of very sharp interfaces, with no diffusion between Si and Ni, indicating that a single buffer layer of CeO2 is sufficient to avoid the formation of nickel silicide while growing Si over Ni substrate. Thus, these results are very encouraging for the fabrication of Poly-Si film based solar cells with increased efficiency by minimizing the undesired recombination of charge carriers at grain boundaries.

Effect Of Heavy Ion Irradiation At Low Temperature In Fe-14Cr-0.2Ti-0.3Y2O3

Sruthi Mohan; S. Balaji; S. Amirthapandian; C. David; B.K. Panigrahi

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 442-445
DOI: 10.5185/amlett.2015.5732

Fe-14Cr-0.2Ti-0.3Y2O3, ODS alloy samples are irradiated with 880 keV Fe + ions at 230 K and 300 K upto a damage of 40 dpa at the surface. Transmission electron microscopy studies reveal a reduction in sizes of oxide dispersions in the ion irradiated alloys as compared to the as-prepared specimens; with greater diminution for samples irradiated at 230 K. Although the ion irradiation conditions (stage III) are favorable for vacancies to couple with solute atoms to cause precipitate growth, it is shown that such effects are less pronounced here and the ballistic effects dominate to cause oxide particle dissolution.

Quantum Chemical Studies Of Nitrogen Substitution On ZnO Nanoclusters Stability

S. Sriram; R. Chandiramouli; A. Thayumanavan

Advanced Materials Letters, 2015, Volume 6, Issue 5, Pages 446-451
DOI: 10.5185/amlett.2015.5786

Importance of p-type transparent conducting oxide (TCO) is much needed in the optoelectronics industry. Due to lack of intrinsic p-type TCO, it is necessary to design or tune the properties existing n-type TCO are very essential. This present work describes, n-type ZnO is tuned to p-type by doping of nitrogen on to the nanocluster. The structural stability of ZnxOx-1N for x=(2-5) is optimized using Gaussian 09 program package with a B3LYP/6-31G level basis set. The optimization result shows that when the cluster size increases the stability also increases. The dipole moment depends on the structure of the ZnxOx-1N cluster. These optimized structural geometries are used to calculate the binding energy, HOMO-LUMO energy gap, ionization potential and electron affinity of nanoclusters. The binding energy for ring structures is found to be more than the other two structures. Vibrational analysis is carried out for all the structures and reported. The ring structure is found to be more stable than the linear and 3D structures. The findings of the present work will provide an insight to synthesis, p-type ZnO nanoclusters.