Volume 6, Issue 8, August 2015

 Research Progress Of “Nanomaterials” In Ten Years

Lokman Uzun

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 670-672
DOI: 10.5185/amlett.2015.8001

After starting to compile one of the growing subject areas of “Energy” under Advanced Materials research in the last issue, we have extracted the data in accordance to cover “Nanomaterials” for the current issue. Herein, we collected the data for last ten years and separated into 1) beginning of five years and 2) latter five years. The comparative research progress of “Nanomaterials” has been achieved at two time intervals through last ten years. In this respect, we discuss the variations in the document types and subject area meanwhile we also present the variation in the ranking of top-ten countries working in the field .

 Ion Induced Modification Of Structural And Photoluminescence Properties Of  Y2O3:Eu3+/ Tb3+ Nanophosphors: A Comprative Study

S. Som; S. Dutta; Subrata Das; Mukesh Kumar Pandey; Ritesh Kumar Dubey; S. P. Lochab; S. K. Sharma

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 673-677
DOI: 10.5185/amlett.2015.5927

Herein, a comparative study on the structural and luminescence properties of optimized Y2O3:Eu 3+ /Tb 3+ nanophosphor has been reported after 150 MeV Ni 7+ , 120 MeV Ag 9+ and 110 MeV Au 8+ ion beam irradiation at various fluences ranging from 1×10 11 to 1×10 13 ions/cm 2 . The X-ray diffraction results confirm the cubic phase in case of unirradiatedY 2 O 3 :Eu 3+ /Tb 3+ nanophosphor. The loss of crystallinity was observed after ion irradiation and Au ion is more effective to damage the crystal structure in these phosphors. The transmission electron microscopic results show the reduction of the particle size from 100 nm to 50, 30 and 20 nm after ion irradiation with the Ni 7+ , Ag 9+ and Au 8+ ions, respectively. Diffuse reflectance spectra show a blue shift in the absorption band owing to the increase in the band gap after ion irradiation. An increase in the photoluminescence intensity without any shift in the peak positions was observed with the increase in the ion fluence. The colour tunability was observed with ion irradiation as the colour coordinate varies from red to white chromaticity.

Multiferroic Properties In Nanostructured Multilayered Magnetic Semiconductor Bi0.9La0.1Fe0.9Co0.1O3-BiFeO3 Thin Films

V. Annapu Reddy; Navneet Dabra; K. K. Ashish; Jasbir S. Hundal; N. P. Pathak; R. Nath

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 678-683
DOI: 10.5185/amlett.2015.5802

Multilayers with nanostructured thin films of Bi0.9La0.1Fe0.9Co0.1O3-BiFeO3 (BLFCO-BFO) were grown on Zn0.91Mn0.09O (ZMO) buffered Si (100) substrate by chemical solution deposition. Structural analysis indicates that rhombohedral crystal structure of BFO, changes to orthorhombic for BLFCO film. Increased ferroelectric saturation and reduced leakage current were obtained for bi-layered and four-layered thin films and are compared with those of BFO and BLFCO thin films.Improvement in ferroelectric properties, as well as induced ferromagnetism was enhanced for four-layered thin films than two-layered thin films. The interface coupling and interaction between the thin layers has led to the resultant improvements. Highly enhanced ferroelectric fatigue properties are observed in these multilayer films up to 10 8 switching cycles.

 Effect Of Nanoclay On The Toughness Of Epoxy And Mechanical, Impact Properties Of E-glass-epoxy Composites

K. Krushnamurty; I. Srikanth; B. Rangababu; S. K. Majee; R. Bauri; Ch. Subrahmanyam

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 684-689
DOI: 10.5185/amlett.2015.5817

Organically modified montimorillonite nanoclay was added to the epoxy and E-glass-epoxy composites. The influence of nanoclay content (varied between 0 to 5wt %) on the relative crosslink density and the fracture toughness of the epoxy matrix was studied. Differential scanning calorimetry (DSC) indicated that the amino functional groups present on the nanoclay react with the epoxy matrix to increase the crosslink density of about 13 and 18% at 3 and 5wt% addition, respectively. The toughness of the epoxy composites increased by 25% at 3wt% addition of nanoclay, whereas, it decreases at 5wt%. Flexural strength and tensile strength of the E-glass-epoxy composites were found to increase by 12% and 11% respectively at 3wt% addition of nanoclay, while at 5wt% addition these properties decreased due to the matrix embrittlement.  Interestingly matrix embrittlement is found to be beneficial in increasing the impact resistance due to spallation of embrittled matrix that ensures the dissipation of the impact energy. 5wt% nanoclay addition increases the impact strength by 29% and reduces the back face bulge of composite by 31%. These results may lead to the design and realization of glass-epoxy composites with better impact strength.

Competition Between Layering & Nano-clustering Of Indium Atoms On Reconstructed Si (113) 3x2 Surface

Shibin T. C. Krishna; Prachi Rastogi; Neha Aggarwal; Amit Kumar Singh Chauhan; Mukesh Kumar; Govind Gupta

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 690-694
DOI: 10.5185/amlett.2015.5822

Scanning tunneling microscopy and X-ray photoelectron spectroscopy have been utilized to probe the growth kinetics, phenomenon of nucleation and segregation of Indium nano-islands on atomically clean stepped Si (113) 3x2 surface. Kinetically controlled growth of few monolayers (2.5 ML) of Indium (In) atoms at room temperature leads the formation of two dimensional (2D) nanoclusters on Si (113) surface. The thermal stability of these In nanoclusters was investigated by residual thermal desorption experiments where the In adsorbed system was annealed at different temperatures (100-600 o C). It is found that, the size and density of the In nanoclusters on Si surface were influenced by the annealing temperature. In particular, on annealing the In/Si (113) system at 300 °C, 2D nanoclusters were converted into a metastable state of 3D nanoclusters. Competition between layering and nano-clustering has been observed twice during the entire thermal annealing process and discussed in detail. The size tunability of these metal nanoclusters on silicon surfaces could be utilized for the fabrication of next generation nanoscale devices.

Nano Sized C-doped TiO2 As A Visible-light Photocatalyst For The Degradation Of 2,4,6- Trichlorophenol

Atul B. Lavand; Yuvraj S. Malghe

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 695-700
DOI: 10.5185/amlett.2015.5800

Nanosized bare and carbon (C)-doped TiO2 were prepared using reverse micro-emulsion method. Synthesized powders were characterized with the help of X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray spectroscope (EDX) and UV-visible spectrophotometer. EDX study reveals that as calcination temperature increases amount of C on TiO2 decreases. SEM and TEM images show that TiO2 particles are spherical in shape and after increasing the calcination temperature size of particle increases. Particle size of TiO2 obtained from TEM data varies between 10 to 17nm.  Visible light photocatalytic degradation of 2,4,6-trichlorophenol (TCP) aqueous solution was carried out using nanosized bare as well as C-doped TiO2. UV-visible spectrophotometer and high pressure liquid chromatography (HPLC) techniques were used to analyze the concentration of TCP during the degradation process. In presence of visible light C-doped TiO2 obtained after calcination of precursor at 300°C shows better photocatalytic activity. Parameters affecting the photocatalytic process such as calcination temperature, amount of catalyst and TCP concentration are investigated. TCP photocatalytic degradation process was optimized. It is observed that to get better photocatalytic activity optimum amount of photocatalyst and concentration of TCP solution required are 1.0 gL -1 and 20 mg L -1 respectively. Reusability study indicates that C doped TiO2 prepared in the present work is highly stable and reusable photo catalyst.

Dual Mode Emission In NaYF4:Yb Er Nanorods For Photovoltaics Application

Ashwani Kumar; Surya Kant Tripathi; Abhay D. Deshmukh

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 701-705
DOI: 10.5185/amlett.2015.5869

In the present study, synthesis, characterization, of dual mode emission (Up and downconversion) in lanthanide-doped NaYF4 nanorods is presented. The unique and rich energy-level structure of these lanthanide ions allows for efficient spectral conversion, including up and downconversion processes mediated by resonant energy transfer between neighboring lanthanide ions. The careful examination of nanorods indicates the perfect uniformity, monodispersity and well defined crystallographic facets. Er 3 + , Yb 3 + doped NCs exhibit green/red dual mode emission with low power density. As solar cells have majority of losses due to spectral mismatch, so with the help of these dual mode emission of nanorods can be utilized as up/down converter to increase the efficiency solar cell.

Electrospun Self-assembled ZnO Nanofibers Structures For Photocatalytic Activity In Natural Solar Radiations To Degrade Acid Fuchsin Dye

Ashish Gupta; Deoram V. Nandanwar; Sanjay R. Dhakate

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 706-710
DOI: 10.5185/amlett.2015.5834

Zinc oxide (ZnO) nanoparticles, self-assembled in the form of one dimensional ZnO nanofibers were synthesized using electrospinning technique from solution of polyvinyl alcohol (PVA) and zinc acetate followed by calcination at 600°C in oxidizing environment. Scanning Electron Microscope (SEM) analysis demonstrates that morphology of ZnO nanofibers having rough surface and corresponding Energy Dispersive Spectrometry (EDAX) confirmed the Zn: O atomic ratio approximately in 50:50. Transmission electron microscopy (TEM) images clearly demonstrate the rough morphology is due to the self-assembling of ZnO nanoparticles having diameter approximately 50nm. X-ray Diffraction (XRD) reveals the polycrystalline structure and Raman spectra show some shifts in phonon modes. The PL graph show exceptional emission at 342nm due to band-band transition. Under solar radiations as produced ZnO nanofibers degrades the 99% of 25ppm acid fuchsine which proven through UV spectra when compared to blank dye solution. This shows that natural solar radiations are sufficient to excite theses self-assembled high surface area ZnO nanofibers to show its photocatalytic activity.

Fabrication And Characterization Of SWCNT- Reinforced Polyester Nanocomposites Using Tensile Test And Nanoindentation Techniques

Minh-Tai Le;Shyh-Chour Huang

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 711-716
DOI: 10.5185/amlett.2015.5821

The main objective of this work is to conduct a manufacturing experiment on a single-walled carbon nanotube (SWCNT)/polyester nanocomposite for characterization of its mechanical properties using a tensile test and nanoindentation techniques. Experimental specimens were made under identical conditions using the hot press process. Dispersion of SWCNTs in an unsaturated polyester matrix was conducted by a sonication method, and a high-speed shear mixer was used for mixing the curing agent and resin. Following the manufacturing of the SWCNT/polyester nanocomposites, characterization of the mechanical properties of the material was performed by tensile testing and nanoindentation techniques. In addition, the morphologies of the fractured surface of SWCNT/polyester nanocomposites were observed with a scanning electron microscope (SEM). The results of mechanical tests exhibit improvements of Young’s modulus and hardness by 35% and 29%, respectively, at 1.0 wt% SWCNTs. In addition, the elastic modulus determined by the nanoindentation technique differs from the one obtained from tensile tests by 16%. The experimental samples are expected to yield the novel promising materials that offer a low-cost, high-strength material for use in the manufacture of lightweight components for automobiles, transportation systems and consumer products.

Effect Of Grain Size On The Structural And Magnetic Properties Of Nanocrystalline Al3Fe5O12 By Aqueous Coprecipitation Method

S.E.Naina Vinodini

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 717-725
DOI: 10.5185/amlett.2015.5874

Al3Fe5O12 (AIG) nanopowders were synthesized at different pH using aqueous co-precipitation method. The effect of pH on the phase formation of AIG is characterized using XRD, TEM, FTIR and TG/DTA. From the Scherer formula, the particle sizes of the powders were found to be 15, 21, 25 and 30 nm for pH= 9, 10, 11 and 12, respectively. It is found that as the pH of the solution increase the particle size also increases. It is clear from the TG/DTA curves that as the pH is increasing the weight losses were found to be small. The nanopowders were sintered at 900°C/4hrs using conventional sintering method. The phase formation is completed at 800°C/4h which is correlated with TG/DTA. The average grain size of the samples is found to be ~55 nm. As the pH increases the magnetization values are also increasing. The saturation magnetization was found to be 4 emu/g, 6 emu/g, 7 emu/g and 9 emu/g corresponding to pH= 9, 10, 11 and 12, respectively which clearly shows that the magnetization values are dependent on pH. Room temperature magnetization measurements established these compounds to be soft magnetic.  The dielectric and magnetic properties (εʹ, εʺ, µÊ¹ and µÊº) of AIG was studied over a wide range of frequency (1GHz-50GHz). With increase of pH both εʹ and µÊ¹ increased. This finding provides a new route for AIG materials that can be used in the gigahertz range.

Phytochemical Fabrication And Characterization Of Silver/ Silver Chloride Nanoparticles Using Albizia Julibrissin Flowers Extract

Akl M. Awwad

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 726-730
DOI: 10.5185/amlett.2015.5816

Silver/ silver chloride (Ag/AgCl-NPs) nanoparticles were synthesized by a simple procedure using Albizia julibrissin flowers extract. The flowers of Albizia julibrissin extract acts a reducing, chlorinated and capping agent in the formation of Ag/AgCl-NPs. UV-visible spectroscopy was used to monitor the quantitative formation of silver/ silver chloride nanoparticles. For complete conversion of silver ions to silver/ silver chloride nanoparticles, time of reaction is less than 5 min at temperature 80 o C and 24h in dark conditions at room temperature. The synthesized Ag/AgCl-NPs nanoparticles were characterized with X-ray diffraction (XRD), UV-vis Spectroscopy, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FT-IR). UV-visible absorption studies revealed surface plasmon resonance (SPR) peak around 410-430 nm, confirming the presence of Ag/AgCl nanoparticles. The average particle size ranged from 5-20 nm. The particle size could be controlled by changing the flowers extract, silver ion concentration and temperature. FT-IR spectra of flowers extract before and after the synthesis of silver/ silver chloride nanoparticles were determined to allow identification of possible functional groups responsible for the reduction of silver ions to silver/silver chloride nanoparticles.

 Investigation Into The Suitability Of Kenaf Fiber To Produce Structural Concrete

Noor Md. Sadiqul Hasan; Habibur Rahman Sobuz; Abubakar Sharif Auwalu; Nafisa Tamanna

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 731-737
DOI: 10.5185/amlett.2015.5818

This paper investigates of an experimental research that was conducted to study the effect of natural kenaf fiber on concrete production which implements in the sustainable construction industry as a low-cost material. Concrete produced with kenaf fiber reinforced concrete (KFRC) with fiber volume contents are increasing 0%, 1%, 3% and 5% in the mix proportions. The concrete fresh properties consisting slump and density are determined in the laboratory. The compressive strength, compacting factor test, modulus of rupture, surface strength, and direct shear test of KFRC specimens are investigated and compared to the properties of conventional concrete specimens. A total number of 36 concrete cubes with the size of 150 mm x 150 mm x 150 mm were tested for compressive strength, 36 Concrete beams with the size of 100 mm x 100 mm x 350 mm were tested for flexural strength, and also 36 concrete small beams with the size of 100 mm x 100 mm x 350 mm were tested for direct shear test. All of the specimens were cured for 7, 14 and 28 days before testing. The experimental results indicate that the mechanical and fresh properties of KFRC are decreased then the conventional concrete specimens with the increased of kenaf fiber content. It is also observed that the additions of fiber decreased the ultimate load of the concrete for compressive strength, modulus of rupture and direct shear test. However, kenaf fiber concrete enhanced more toughness and ductility behaviour compared with the conventional concrete. Finally, it concluded that kenaf fiber is a suitable material that could potentially be used to produce low-cost ‘green’ concrete which has higher toughness and reduce the cracking propagation in the concrete structural applications.

SnO2 Nanoparticles Synthesis Via Liquid-phase Co-precipitation Technique 

G. T. Lamdhade; F. C. Raghuwanshi; R. M. Agrawal; V. M. Balkhande; T. Shripath

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 738-742
DOI: 10.5185/amlett.2015.5877

The samples have been prepared in the form of pellets of SnO2 nanoparticles and synthesized via the liquid-phase co-precipitation technique. The ac electrical conductivity of samples is found to be frequency dependent. The dielectric constant increases with temperature and decreases with frequency of applied field. The semiconducting behavior of SnO2 nanoparticles have been studied from I-V characteristics. The characterization of samples has been studied by XRD, FESEM, UV-spectra and TG-DTA plot

Erbium Induced Raman Studies And Dielectric Properties Of Er-doped ZnO Nanoparticles

C. Jayachandraiah; G. Krishnaiah

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 743-748
DOI: 10.5185/amlett.2015.5801

Pure and erbium (1.30, 1.79, 2.83 and 3.53 at. %) doped ZnO nanoparticles are synthesized by wet chemical co-precipitation method. The synthesized samples are characterized by powder X-ray diffraction (XRD), energy-dispersive analysis of X-rays (EDAX), transmission electron microscopy (TEM), Raman spectroscopy, UV–visible diffusion reflectance spectroscopy (DRS) and LCR Impedance spectroscopy. The XRD measurements confirmed the hexagonal wurtzite structure of all samples and size of the particle is found to be decreased with Er content. TEM images show spherical shape with more agglomeration in Er doped ZnO nanoparticles. Raman spectra confirmed the hexagonal wurtzite structure of pure and Er doped ZnO nanoparticles with E2 (high) mode at 438 cm -1 and presence of other possible defects. UV visible DRS shows decrease in the band gap with increasing Er 3+ in ZnO host. Dielectric constant, dielectric loss factor and ac conductivity properties were decreased with Er dopant in tune with Maxwell -Wagner principle and surface-orientation polarizations.

An Investigation Of Electrical, Magnetic And Optical Properties Of La1-xCaxMnO3 (x= 0.0, 0.3, 0.5 And 0.7) System

Khalid Sultan; M. Ikram

Advanced Materials Letters, 2015, Volume 6, Issue 8, Pages 749-755
DOI: 10.5185/amlett.2015.5875

Results from a detailed investigation on the structural, optical, electrical and magnetic properties of polycrystalline bulk samples of La1-xCaxMnO3 (x=0, 0.3, 0.5 and 0.7) synthesized by solid state reaction method are presented. The Rietveld analysis of the X-Ray diffraction (XRD) profiles clearly indicated that the XRD patterns are well fitted with orthorhombic structure. Raman spectral features revealed their finger print modes and irreducible representations at the brillouin zone center as per the group theory. It is also observed that as doping is increased, these compounds tend towards a cubic form. Ooptical band gap ‘Eg’ study reveals that the Eg decreases with Ca doping resulting in increase in conductivity. This is consistent with the resistivity measurements. In all the samples, except when x = 0.0 and 0.7, the resistivity at the highest temperature measured (ρ300 K) is less than that at 5 K (ρ5K), although for temperature T<Tp, the material shows a metal variation of ρ with temperature (d ρ/dT > 0) whereas the value of ρ300 K decreases as x increases. Magnetization study revealed that temperatures corresponding to magnetic transitions Tc increases with doping. It is observed that the composition x = 0.5 show both a paramagnetic to ferromagnetic transition and an antiferromagnetic transition. An effort has been made to relate above observed results in the compound with the structural changes brought about by Ca doping.Possible mechanisms such as activated transport and Zener double exchange are used to understand the phase diagram of these materials.