Volume 5, Issue 4, April 2014


Editorial

International Conference On Smart Materials And Surfaces (SMS), Bangkok

Ashutosh Tiwari

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 161-162
DOI: 10.5185/amlett.2014.4001

We are pleased to announce International Conference on Smart Materials and Surfaces (SMS). It will be organised jointly by SETCOR, IAAM and VBRI Press during 26-28 August 2014 at Sheraton Grande Sukhumvit Hotel, Bangkok, Thailand. Smart Materials and Surfaces (SMS), Bangkok is a three-day event targeting researchers interested in the design, modification, characterisation and applications of Novel Smart & Active Surfaces and Materials. The goal of conference 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 Intelligent Materials science and engineering. The conference will provide opportunities for the delegates to exchange face-to-face their novel ideas and experiences with the international experts during plenary & invited talks, oral presentations and poster sessions. We will set up sessions with keynote forum, panel discussion, project negotiation along with welcome cocktail and gala dinner.

Fabrication And Characterization Of Efficient Hybrid Photocatalysts Based On Titania And Graphene For Acid Orange Seven Dye Degradation Under UV Irradiation

P. Muthirulan; C. K. N. Devi; M. M. Sundaram

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 163-171
DOI: 10.5185/amlett.2013.7507

Simple and proficient methodology has been proposed for the preparation of hybrid photocatalyst based on titanium dioxide (TiO2)-graphene (GR) nanocomposite for acid orange 7 (AO7) dye degradation under UV irradiation. High Resolution Transmission Electron Microscopy (HRTEM) and Scanning Electron Microscopy (SEM) studies revealed that TiO2 nanoparticles were uniformly dispersed on GR surface. TiO2-GR hybrid nanocomposite has also been characterized by Ultraviolet Diffusive Reflectance Spectroscopy (UV-DRS), Raman spectroscopy and X-ray diffraction (XRD) studies. Electrochemical Impedance spectroscopy (EIS) measurement revealed that the incorporation of GR with TiO2 nanoparticles significantly enhanced the electrical conductivity.The peak intensity of PL spectra of GR containing catalysts are lower than that of pristine TiO2, indicating that the electron–hole recombination rate of self-trapped excitations in TiO2 is reduced by the introduction of GR. The photocatalytic degradation measurements demonstrated that the TiO2-GR composites exhibited an enhanced photocatalytic activity for AO7 degradationunder UV irradiation compared to pure TiO2. This may due to greater adsorptivity ofdyes, extended light absorption and increased charge separation efficiency due to excellent electricalproperties of graphene and the large surface contact between graphene and TiO2 nanoparticles. Therefore, the TiO2-GR composites can be widely used as a ternary composite photocatalyst for treating the organic contaminant in the field of environmental protection.

Effect Of Process Parameters On The Properties Of Ultrananocrystalline Diamond Films Deposited Using Microwave Plasma Enhanced Chemical Vapor Deposition

Vijay Chatterjee; Rishi Sharma; P. K. Barhai

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 172-179
DOI: 10.5185/amlett.2013.10550

Ultrananocrystalline diamond (UNCD) films are deposited using microwave plasma enhanced chemical vapor deposition system. Depositions of films are carried out at low pressure 25 mbar, low temperature 400 ºC and at low microwave power (800 - 1000 Watt). Diamond thin films were characterized using Raman spectroscopy, AFM, field emission scanning electron microscopy and optical contact angle measurements. In-situ diagnosis of the plasma composition is carried out using optical emission spectroscopy (OES). OES spectra show intense peak at 516.5nm corresponding to C2 dimer. Peaks at 387.0nm, 405.3nm, 431.5nm, 486.1nm, and 656.1nm have also been observed. Effect of horizontal position of plasma ball with respect to substrate position has been critically analyzed. Relation between the horizontal positioning and plasma ball along with the emission spectra of different gas species are studied which are very much crucial to predict the uniformity and morphology of the films deposited. Dependence of film wetability with the plasma ball positioning and relative intensity of carbon dimer has been studied C2 dimer plays an important role not only in the nucleation and growth of UNCD films but also on the surface modification .

Towards Fabrication Of Stable Dye Sensitized Solar Cells Based On Acetonitrile As Solvent For The Redox Couple

Ambily Mathew; G. Mohan Rao; N. Munichandraiah

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 180-183
DOI: 10.5185/amlett.2013.8527

The present paper describes the scheme used to fabricate completely sealed dye sensitized solar cell (DSC) and its stability analysis employing acetonitrile as the solvent for redox couple. Since acetonitrile is extremely volatile a perfect sealing is essential to prevent the leakage of electrolyte. The usual hot melt sealing is employed for edge sealing whereas hole sealing is carried out with tooth pick and a UV curable adhesive. The degradation in efficiency is found to be 20% for low efficiency cells whereas, for high efficiency cells it is found to be 45% after 45 days. The leakage of highly volatile acetonitrile through the edge and hole is mainly responsible for the reduction in the performance of the device. Hence a high temperature sealing method is proposed to fabricate stable cells.

High Rate Capability Of Coconut Kernel Derived Carbon As An Anode Material For Lithium-ion Batteries

Tirupathi Rao Penki; Brij Kishore;N. Munichandraiah; D. Shanmughasundaram

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 184-190
DOI: 10.5185/amlett.2013.8530

Carbon has been prepared by pyrolysis of grated, milk-extracted coconut kernel at 600 ºC under nitrogen atmosphere. The disordered carbon has sheet like morphology. The carbon exhibits a high reversible Li + intercalation capacity in a non-aqueous electrolyte. The initial charge and discharge capacities are 990 and 400 mAh g -1 , thus resulting in an irreversible capacity loss of 590 mAh g -1 . Nevertheless, subsequent discharge capacity is stable over a large number of charge-discharge cycles. The electrodes withstand charge-discharge currents as high as 1257 mA g -1 and they deliver discharge capacity of 80 mAh g -1 . Diffusion coefficient of Li+ obtained from galvanostatic intermittent titration is 6.7 x 10 -12 cm 2 s -1 . Thus the coconut kernel derived carbon is a suitable anode material for Li-ion batteries.

Synthesis Of Air Stable Copper Nanoparticles And Their Use In Catalysis

Razium Ali Soomro; Syed Tufail Hussain Sherazi; Najma Memon; Mohammad Raza Shah; Nazar Hussain Kalwar; Keith Richard Hallam; Afzal Shah

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 191-198
DOI: 10.5185/amlett.2013.8541

The undertaken study describes synthesis of air resistant copper nanoparticles (Cu NPs) in an aqueous phase using sodium borohydride as a reducing agent via chemical reduction method. The hydrosol has resistant to oxidation by atmospheric oxygen for several days. The air stability was induced by capping Cu NPs with anionic surfactant “sodium dodecyl sulfate (SDS)”.  Ascorbic acid was used as an antioxidant. These Cu NPs were characterized by ultraviolet-visible (UV-VIS) spectroscopy, which contributed towards the understanding of surface plasmon resonance (SPR) generation and optical behavior of Cu NPs. It was used as an optical tracer for size control and confirmation of Cu NPs and was found to be affected by various parameters like reaction time, pH, concentration of copper sulfate and the surfactant SDS. SPR peaks were found to shift from 597 to 569 nm, while apparent color changes from yellow to brick red.  Further characterization studies were carried out by using fourier transform infrared (FT-IR) spectroscopy to investigate the co-ordination between Cu NPs and SDS. X-ray diffraction (XRD) was used for phase purity of Cu NPs. Transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used the size and morphological characterization. The average size of the Cu NPs was found to be 15 nm in diameter with an average height of 14 nm. The Cu NPs showed excellent catalytic activity in the reductive degradation of Eosin B (EB) dye in just 16 sec of reaction time and maintained their catalytic activity when reused multiple times. The degradation rate was found to follow first order reaction kinetics with the EB degradation. The Cu NPs enhanced the rate of EB degradation 30 times more than the control test. Copper was found an attractive catalyst in the nanosize regimes. The Cu NPs are more economical as compared to noble metals. The Cu NPs are expected to be suitable alternative and play an imperative role in the fields of catalysis and environmental remediation.

Structural, Optical And Magnetic Properties Of (Fe, Ag) Co-doped ZnO Nanostructures

B. Sankara Reddy; S. Venkatramana Reddy; N. Koteeswara Reddy; Y. Prabhakara Reddy

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 199-205
DOI: 10.5185/amlett.2013.8529

The (Fe, Ag) co-doped ZnO nanostructures are developed through chemical precipitation method at various percentages of Fe. The X-ray diffraction studies suggest that all the as-synthesized (Fe, Ag) doped ZnO nanopowders have single phase wurtzite structure with no secondary phases. However, the positions of diffracted peaks slightly shifted towards lower (2θ) angles. Photoluminescence studies reveal that 1 mol% of Fe doped ZnO sample has the best ultra violet (UV) emission properties than the other samples. On the other hand, 5 mol% of Fe doped ZnO nanopowders consists of strong green emission band, which belongs to oxygen interstitial defect states. Magnetization analysis shows that 5 mol% of Fe doped ZnO nanopowders have highest room temperature ferromagnetism (RTFM) than the RTFM of other samples. The observed RTFM in co-doped ZnO nanopowders is discussed with the help of structural and emission studies. The results strongly suggest the future development of efficient luminescence and magnetic materials at normal laboratory temperatures with (Fe, Ag) co-doped ZnO nanostructures.

Synthesis And Characterization Of Thermally Resistant Aromatic Polyamide-metal Complexes

Sandeep Rai; Anjali Bajpai; Snehal Lokhandwala

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 206-213
DOI: 10.5185/amlett.2013.7509

Amino group terminated oligomeric aromatic polyamides were prepared using phosphorylation technique and subsequently converted into Schiff’s base coordination polymers by reaction with Co (II), Ni (II) and Cu (II) complexes of salicyladehyde [M(SAL)2] and 2-hydroxy-1-naphthaldehyde [M(NAPHTHAL)2]. These polyamide metal complexes were characterized by elemental analysis, IR spectroscopy and thermo gravimetric analysis; and an oxygen and nitrogen coordinated structure was inferred. Magnetic moment values of the different products indicated the variation in geometry. Introduction of metal ions into the polyamide chains enhanced the thermal stability of the coordination polymers as compared to the respective polymeric ligands.  As an extension of this simple and easy technique, the thermal stability of fibers, films, sheets and blocks of amino group containing polyamides can be increasing by introduction of metal ions through Schiff base formation. These polyamide Schiff base complexes are expected to show promising antimicrobial activities.

Synthesis And Evaluation Of Swelling Characteristics Of Fullerene (C60) Containing Cross-linked Poly(2-hydroxyethyl Methacrylate) Hydrogels

Rashmi Katiyar; Dibyendu S Bag; Indira Nigam

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 214-222
DOI: 10.5185/amlett.2013.8532

Fullerene containing cross-linked poly (2-hydroxyethyl methacrylate) polymers (CFPH) with varying C60 content were synthesized by free radical polymerization. The fullerene content in the cross-linked polymers was determined by TGA analysis. The swelling properties of these fullerene containing hydrogels (CFPH) were studied in distilled water (pH=7.2) at room temperature (25 o C) and compared to the corresponding hydrogel without fullerene (CPHEMA). The equilibrium swelling ratio is lower for the fullerene containing hydrogels (54.68% and 40.0% for hydrogels having 6.0 wt% and 18.0 wt% fullerene respectively) due to the presence of hydrophobic fullerene moieties inside the hydrogels than that of the hydrogel (68.75%) without fullerene. The hydrophobic fullerene nanomaterials acting as inherent nanofillers obstruct the path of water permeation inside the polymers thereby taking more time to achieve equilibrium swelling for fullerene containing hydrogels than that of the hydrogel without fullerene. The kinetics of swelling behavior of such fullerene containing cross-linked hydrogels (CFPH) was observed to follow Fickian behavior. Increase of temperature and ionic strength of the medium decrease the water uptake capacity of the fullerene containing cross-linked hydrogels. Fullerene containing hydrogels may be useful in drug delivery system and other biomedical applications.

Interfacial Mixing In Te/Bi Thin Film System

T. Diana; D. C. Agarwal; P. K. Kulriya; S. K. Tripathi; H. Nandakumar Sarma

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 223-228
DOI: 10.5185/amlett.2013.7510

100 MeV Ag ions have been used to study the swift heavy ion (SHI) induced modification in Te/Bi bilayer system. The samples were analysed using Rutherford backscattering spectroscopy (RBS), Atomic force microscopy (AFM) and X-ray diffractometer (XRD). The elemental depth study with RBS results show a strong mixing between the top Te layer and the underlying Bi layer on irradiation. Surface roughness as calculated by AFM is found to increase from 8 to 30 nm on irradiation for the fluence 3x10 13 ions/cm 2 .  XRD results confirm the formation of Bi-Te alloy phases on mixing and are expected to be formed due to the interfacial reaction taking place within the molten ion tracks. Ion beam mixing has the potential to induce the formation Bi-Te alloy thin films which are the promising candidate for thermoelectric applications near room temperature.

Multiferroic Properties Of 0.05 NZF - 0.95 Ba0.9-3x/2Sr0.1LaxTiO3 Magnetoelectric Composites

Renu Rani; K. K. Raina;Chandra Prakash; J. K. Juneja; Sangeeta Singh

Advanced Materials Letters, 2014, Volume 5, Issue 4, Pages 229-233
DOI: 10.5185/amlett.2013.fdm.63

For the present work, the magnetoelectric (ME) composites with composition 0.05 Ni0.8Zn0.2Fe2O4 - 0.95 Ba0.9-3x/2Sr0.1LaxTiO3(NZF-BSLT) with x = 0, 0.01and 0.02 were synthesized by conventional solid state reaction route. The existence of both phases was confirmed by the X-Ray diffraction (XRD) technique. The dielectric properties such as dielectric constant and dielectric loss were measured as a function of temperature at different frequencies. P-E hysteresis loops and M-H hysteresis loops confirm the ferroelectric and ferromagnetic nature of the composite samples.La substitution in ferroelectric phase results in significant improvement in properties of composite samples. The investigated composites seem to be very attractive for multiple state memory devices where data can be stored both as polarization (P) and magnetization (M).