Journal of Nanomaterials http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. Ge Nanoislands Grown by Radio Frequency Magnetron Sputtering: Comprehensive Investigation of Surface Morphology and Optical Properties Thu, 26 Mar 2015 14:27:57 +0000 http://www.hindawi.com/journals/jnm/2015/681242/ The comprehensive investigation of the effect of growth parameters on structural and optical properties of Si-based single layer Ge nanoislands grown via Stranski-Krastanov mechanism employing radio frequency magnetron sputtering due to its high deposition rate, easy procedure, economical cost, and safety is carried out. The estimated width and height of Ge nanoislands produced by this technique are in the range of ∼8 to ∼30 and ∼2 to 8 nm, respectively. Varieties parameters are manipulated to optimize the surface morphology and structural and optical behavior of Ge nanoislands. The resulted nanoislands are analyzed using various analytical techniques including atomic force microscope, X-ray diffraction, energy dispersive X-ray spectroscopy, room temperature photoluminescence, and Raman spectroscopy. The optimum parameters for growing high quality samples having high number density and homogenous and small size distribution are found to be 400°C for substrate temperature, 300 sec for deposition time, 10 sccm for Ar flow, and 100 W for radio frequency power. The excellent features of the results suggest that our systematic investigation on the organized growth factors and their effects on surface parameters and photoluminescence emission energy may constitute a basis for the tunable growth of Ge nanoislands (100) nanoislands suitable in nanophotonics. Alireza Samavati, M. K. Mustafa, Z. Othaman, and S. K. Ghoshal Copyright © 2015 Alireza Samavati et al. All rights reserved. The Formation of Carbon Nanostructures via Catalytic Pyrolysis of Naphthalene under Its Autogenic Pressure Thu, 26 Mar 2015 08:34:39 +0000 http://www.hindawi.com/journals/jnm/2015/752647/ The formation of carbon nanotubes (CNTs), spherical carbon nanocapsules (CNCs), and carbon spheres (CSs) is accomplished by using the method of reactions under autogenic pressure at elevated temperatures (RAPET). A powder mixture of naphthalene and nickel acetate tetrahydrate is dissociated under its autogenic pressure. The resultant CNTs and CNCs exhibit good graphitic quality, and the diameters range from 50~200 nm. Smooth and monodisperse CSs with the diameter ranging from 5~10 μm can be obtained by pyrolysis of pure naphthalene. Our results show that the reaction temperature and catalyst proportion play a key role in the formation of carbon nanostructures with RAPET method. Chao-Gang Wang, Xiao-Hong Shao, and Rui-Sheng Xue Copyright © 2015 Chao-Gang Wang et al. All rights reserved. Advances in Functionalized Materials Research Thu, 26 Mar 2015 06:05:46 +0000 http://www.hindawi.com/journals/jnm/2015/412690/ Daniela Predoi, Mikael Motelica-Heino, and Philippe Le Coustumer Copyright © 2015 Daniela Predoi et al. All rights reserved. Functional Nanomaterials for Energy Applications Wed, 25 Mar 2015 11:58:26 +0000 http://www.hindawi.com/journals/jnm/2015/131965/ Rupesh S. Devan, Yuan-Ron Ma, Kin-Hyeok Kim, Raghu N. Bhattacharya, and Kartik C. Ghosh Copyright © 2015 Rupesh S. Devan et al. All rights reserved. Heat Transfer Analysis of MHD Water Functionalized Carbon Nanotube Flow over a Static/Moving Wedge Tue, 24 Mar 2015 13:11:29 +0000 http://www.hindawi.com/journals/jnm/2015/934367/ The MHD flow and heat transfer from water functionalized CNTs over a static/moving wedge are studied numerically. Thermal conductivity and viscosity of both single and multiple wall carbon nanotubes (CNTs) within a base fluid (water) of similar volume are investigated to determine the impact of these properties on thermofluid performance. The governing partial differential equations are converted into nonlinear, ordinary, and coupled differential equations and are solved using an implicit finite difference method with quasi-linearization techniques. The effects of volume fraction of CNTs and magnetic and wedge parameters are investigated and presented graphically. The numerical results are compared with the published data and are found to be in good agreement. It is shown that the magnetic field reduces boundary layer thickness and increases skin friction and Nusselt numbers. Due to higher density and thermal conductivity, SWCNTs offer higher skin friction and Nusselt numbers. Waqar A. Khan, Richard Culham, and Rizwan Ul Haq Copyright © 2015 Waqar A. Khan et al. All rights reserved. Thermoelectric Transport Properties of Cu Nanoprecipitates Embedded Tue, 24 Mar 2015 13:09:53 +0000 http://www.hindawi.com/journals/jnm/2015/820893/ We suggest a simple and scalable synthesis to prepare Cu- (Cu-BTS) nanocomposites. By precipitating Cu nanoparticle (NP) in colloidal suspension of as-exfoliated BTS, homogeneous mixtures of Cu NP and BTS nanosheet were readily achieved, and then the sintered nanocomposites were fabricated by spark plasma sintering technique using the mixed powder as a raw material. The precipitated Cu NPs in the BTS matrix effectively generated nanograin (BTS) and heterointerface (Cu/BTS) structures. The maximum of 0.90 at 400 K, which is 15% higher compared to that of pristine BTS, was obtained in 3 vol% Cu-BTS nanocomposite. The enhancement of resulted from improved power factor by carrier filtering effect due to the Cu nanoprecipitates in the BTS matrix. Eunsil Lee, Jin Il Kim, Soon-Mok Choi, Young Soo Lim, Won-Seon Seo, Jong-Young Kim, and Kyu Hyoung Lee Copyright © 2015 Eunsil Lee et al. All rights reserved. Clarification of the Magnetocapacitance Mechanism for Fe3O4-PDMS Nanocomposites Tue, 24 Mar 2015 06:47:12 +0000 http://www.hindawi.com/journals/jnm/2015/982174/ We mainly focused on the magnetocapacitance effect of Fe3O4-PDMS nanocomposites. We also proposed the preparation method and measured microstructures, magnetic properties, and magnetocapacitance value of the nanocomposites. The magnetocapacitance measurement results show that the nanocomposites have magnetocapacitance property, the magnetocapacitance with magnetic field depends on the magnetic property, and the value at the same magnetic field is increasing with the volume fraction of Fe3O4 nanoparticles. The magnetocapacitance model is proposed to explain this phenomenon by analyzing the magnetic interaction between particles and the viscoelasticity of PDMS. We also calculated the theoretical capacitance value of all samples using the magnetization of nanoparticles and mechanical parameters of PDMS. From the theoretical values, it is concluded that the model we proposed can well explain the magnetocapacitance effect of Fe3O4-PDMS nanocomposites. Chen Guobin, Yang Hui, Zhang Xiaoming, Liu Jun, and Tang Jun Copyright © 2015 Chen Guobin et al. All rights reserved. DMA and Conductivity Studies in PVA:NH4SCN:DMSO:MWNT Nanocomposite Polymer Dried Gel Electrolytes Mon, 23 Mar 2015 12:48:00 +0000 http://www.hindawi.com/journals/jnm/2015/435625/ This paper deals with findings on dynamic mechanical analysis (DMA) and ion-conduction behavior of MWNTs (multiwall carbon nanotubes) doped PVA:NH4SCN:DMSO dried gel electrolyte system prepared for four filler concentrations (2, 4, 6 & 8 wt%) by solution cast technique. XRD measurements reveal enhancement in amorphous behavior of composite gel electrolyte upon incorporation of filler particles. Better mechanical stability is noticed in the composite system upon dispersal of MWNT along with presence of dynamic during DMA measurements. Enhancement in ionic conductivity has been noticed with an optimum value of 4.5 × 10−3 Scm−1 for 6 wt% MWNTs filled composite electrolyte. Composite system exhibits combination of Arrhenius and Vogel-Tammam-Fulcher (VTF) behavior in temperature dependent conductivity study. The a.c. conductivity response seems to follow universal power law. S. L. Agrawal and Neelesh Rai Copyright © 2015 S. L. Agrawal and Neelesh Rai. All rights reserved. Characterization of the Oxides Present in a Polydimethylsiloxane Layer Obtained by Polymerisation of Its Liquid Precursor in Corona Discharge Mon, 23 Mar 2015 08:49:25 +0000 http://www.hindawi.com/journals/jnm/2015/204296/ By combining the reflection-absorption infrared spectral studies with the peak fitting analysis we determined the type of the silicon oxides present in polydimethylsiloxane layers obtained on germanium and aluminium substrates in corona discharges. We have also evidenced that the dependence of silicon oxides density on the corona discharge current intensity is related to the existence of a concurrent anodizing process occurring at the polymer/Al substrate interface. The morphology of the Al substrate surface investigated by scanning electron microscopy proved that the anodizing process occurs. A. Groza and A. Surmeian Copyright © 2015 A. Groza and A. Surmeian. All rights reserved. Graphene and Other 2D Material Components Dynamic Characterization and Nanofabrication at Atomic Scale Sun, 22 Mar 2015 12:51:51 +0000 http://www.hindawi.com/journals/jnm/2015/198126/ We demonstrate how abreaction corrected transmission electron microscopy (TEM) analysis techniques that are commonly used in nanostructure characterization can be used to study the morphology of graphene and other 2D materials at atomic scale, even subangstrom scale, and evolution of nanostructure and from which we determine the graphene components nanofabrication process. The key contributions of this work are perhaps focused on two areas: (1) recent progress on graphene characterization from the TEM aspect and (2) how the electron beam can be used to fabricate nanoribbon from graphene or similar 2D material. Wei Wang, Xing Wu, and Jian Zhang Copyright © 2015 Wei Wang et al. All rights reserved. Comparative Studies on Thermal Performance of Conic Cut Twist Tape Inserts with SiO2 and TiO2 Nanofluids Sun, 22 Mar 2015 12:47:49 +0000 http://www.hindawi.com/journals/jnm/2015/921394/ This paper presents a comparison study on thermal performance conic cut twist tape inserts in laminar flow of nanofluids through a constant heat fluxed tube. Three tape configurations, namely, quadrant cut twisted tape (QCT), parabolic half cut twisted tape (PCT), and triangular cut twisted (VCT) of twist ratio = 2.93 and cut depth = 0.5 cm were used with 1% and 2% volume concentration of SiO2/water and TiO2/water nanofluids. Typical twist tape with twist ratio of = 2.93 was used for comparison. The results show that the heat transfer was enhanced by increasing of Reynolds number and nanoparticles concentration of nanofluid. The results have also revealed that the use of twist tape enhanced the heat transfer coefficient significantly and maximum heat transfer enhancement was achieved by the presence of triangular cut twist tape insert with 2% volume concentration of SiO2 nanofluid. Over the range investigated, the maximum thermal performance factor of 5.13 is found with the simultaneous use of the SiO2 nanofluid at 2% volume concentration VCT at Reynolds number of 220. Furthermore, new empirical correlations for Nusselt number, friction factor, and thermal performance factor are developed and reported. Sami D. Salman, Abdul Amir H. Kadhum, Mohd S. Takriff, and Abu Bakar Mohamad Copyright © 2015 Sami D. Salman et al. All rights reserved. A Review on the Fabrication of Electrospun Polymer Electrolyte Membrane for Direct Methanol Fuel Cell Thu, 19 Mar 2015 14:01:11 +0000 http://www.hindawi.com/journals/jnm/2015/690965/ Proton exchange membrane (PEM) is an electrolyte which behaves as important indicator for fuel cell’s performance. Research and development (R&D) on fabrication of desirable PEM have burgeoned year by year, especially for direct methanol fuel cell (DMFC). However, most of the R&Ds only focus on the parent polymer electrolyte rather than polymer inorganic composites. This might be due to the difficulties faced in producing good dispersion of inorganic filler within the polymer matrix, which would consequently reduce the DMFC’s performance. Electrospinning is a promising technique to cater for this arising problem owing to its more widespread dispersion of inorganic filler within the polymer matrix, which can reduce the size of the filler up to nanoscale. There has been a huge development on fabricating electrolyte nanocomposite membrane, regardless of the effect of electrospun nanocomposite membrane on the fuel cell’s performance. In this present paper, issues regarding the R&D on electrospun sulfonated poly (ether ether ketone) (SPEEK)/inorganic nanocomposite fiber are addressed. Hazlina Junoh, Juhana Jaafar, Muhammad Noorul Anam Mohd Norddin, Ahmad Fauzi Ismail, Mohd Hafiz Dzarfan Othman, Mukhlis A. Rahman, Norhaniza Yusof, Wan Norhayati Wan Salleh, and Hamid Ilbeygi Copyright © 2015 Hazlina Junoh et al. All rights reserved. Multifunctional DNA Nanomaterials for Biomedical Applications Thu, 19 Mar 2015 13:06:12 +0000 http://www.hindawi.com/journals/jnm/2015/765492/ The rapidly emerging DNA nanotechnology began with pioneer Seeman’s hypothesis that DNA not only can carry genetic information but also can be used as molecular organizer to create well-designed and controllable nanomaterials for applications in materials science, nanotechnology, and biology. DNA-based self-assembly represents a versatile system for nanoscale construction due to the well-characterized conformation of DNA and its predictability in the formation of base pairs. The structural features of nucleic acids form the basis of constructing a wide variety of DNA nanoarchitectures with well-defined shapes and sizes, in addition to controllable permeability and flexibility. More importantly, self-assembled DNA nanostructures can be easily functionalized to construct artificial functional systems with nanometer scale precision for multipurposes. Apparently scientists envision artificial DNA-based nanostructures as tool for drug loading and in vivo targeted delivery because of their abilities in selective encapsulation and stimuli-triggered release of cargo. Herein, we summarize the strategies of creating multidimensional self-assembled DNA nanoarchitectures and review studies investigating their stability, toxicity, delivery efficiency, loading, and control release of cargos in addition to their site-specific targeting and delivery of drug or cargo molecules to cellular systems. Dick Yan Tam and Pik Kwan Lo Copyright © 2015 Dick Yan Tam and Pik Kwan Lo. All rights reserved. Effects of Different Doping Ratio of Cu Doped CdS on QDSCs Performance Thu, 19 Mar 2015 12:46:48 +0000 http://www.hindawi.com/journals/jnm/2015/498950/ We use the successive ionic layer adsorption and reaction (SILAR) method for the preparation of quantum dot sensitized solar cells, to improve the performance of solar cells by doping quantum dots. We tested the UV-Vis absorption spectrum of undoped CdS QDSCs and Cu doped CdS QDSCs with different doping ratios. The doping ratios of copper were 1 : 100, 1 : 500, and 1 : 1000, respectively. The experimental results show that, under the same SILAR cycle number, Cu doped CdS quantum dot sensitized solar cells have higher open circuit voltage, short circuit current density photoelectric conversion efficiency than undoped CdS quantum dots sensitized solar cells. Refinement of Cu doping ratio are 1 : 10, 1 : 100, 1 : 200, 1 : 500, and 1 : 1000. When the proportion of Cu and CdS is 1 : 10, all the parameters of the QDSCs reach the minimum value, and, with the decrease of the proportion, the short circuit current density, open circuit voltage, and the photoelectric conversion efficiency are all increased. When proportion is 1 : 500, all parameters reach the maximum values. While with further reduction of the doping ratio of Cu, the parameters of QDSCs have a decline tendency. The results showed that, in a certain range, the lower the doping ratio of Cu, the better the performance of quantum dot sensitized solar cell. Xiaojun Zhu, Xiaoping Zou, and Hongquan Zhou Copyright © 2015 Xiaojun Zhu et al. All rights reserved. Synthesis and Characterization of Hierarchical Structured TiO2 Nanotubes and Their Photocatalytic Performance on Methyl Orange Thu, 19 Mar 2015 12:24:39 +0000 http://www.hindawi.com/journals/jnm/2015/201650/ Hierarchical structured TiO2 nanotubes were prepared by mechanical ball milling of highly ordered TiO2 nanotube arrays grown by electrochemical anodization of titanium foil. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, specific surface area analysis, UV-visible absorption spectroscopy, photocurrent measurement, photoluminescence spectra, electrochemical impedance spectra, and photocatalytic degradation test were applied to characterize the nanocomposites. Surface area increased as the milling time extended. After 5 h ball milling, TiO2 hierarchical nanotubes exhibited a corn-like shape and exhibited enhanced photoelectrochemical activity in comparison to commercial P25. The superior photocatalytic activity is suggested to be due to the combined advantages of high surface area of nanoparticles and rapid electron transfer as well as collection of the nanotubes in the hierarchical structure. The hierarchical structured TiO2 nanotubes could be applied into flexible applications on solar cells, sensors, and other photoelectrochemical devices. Kai Liu, Shiwei Lin, Jianjun Liao, Nengqian Pan, and Min Zeng Copyright © 2015 Kai Liu et al. All rights reserved. Advances in Multiferroic Nanomaterials Assembled with Clusters Thu, 19 Mar 2015 09:14:09 +0000 http://www.hindawi.com/journals/jnm/2015/101528/ As an entirely new perspective of multifunctional materials, multiferroics have attracted a great deal of attention. With the rapidly developing micro- and nano-electro-mechanical system (MEMS&NEMS), the new kinds of micro- and nanodevices and functionalities aroused extensive research activity in the area of multiferroics. As an ideal building block to assemble the nanostructure, cluster exhibits particular physical properties related to the cluster size at nanoscale, which is efficient in controlling the multiferroic properties for nanomaterials. This review focuses on our recent advances in multiferroic nanomaterials assembled with clusters. In particular, the single phase multiferroic films and compound heterostructured multiferroic films assembled with clusters were introduced detailedly. This technique presents a new and efficient method to produce the nanostructured multiferroic materials for their potential application in NEMS devices. Shifeng Zhao Copyright © 2015 Shifeng Zhao. All rights reserved. Hydrothermal Synthesis of Bi2MoO6 Visible-Light-Driven Photocatalyst Thu, 19 Mar 2015 08:38:41 +0000 http://www.hindawi.com/journals/jnm/2015/135735/ Bismuth molybdate (Bi2MoO6) nanoplates were synthesized by the hydrothermal reaction of bismuth nitrate and sodium molybdate as starting materials at 120–180°C for 5–20 h. X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, and scanning electron microscopy (SEM) were used to investigate the effect of reaction temperature and length of reaction time on phase and morphologies of the as-synthesized Bi2MoO6 samples. In this research, orthorhombic well-crystallized Bi2MoO6 nanoplates with the presence of stretching and bending vibrations of MoO6 and BiO6 octahedrons were detected, and the Bi2MoO6 nanoplates synthesized at 180°C for 5 h exhibit the highest photocatalytic efficiency over 96% within 100 min visible-light irradiation. Anukorn Phuruangrat, Sunisa Putdum, Phattranit Dumrongrojthanath, Somchai Thongtem, and Titipun Thongtem Copyright © 2015 Anukorn Phuruangrat et al. All rights reserved. Characterization of Carbon Nanotube/Graphene on Carbon Cloth as an Electrode for Air-Cathode Microbial Fuel Cells Thu, 19 Mar 2015 08:07:53 +0000 http://www.hindawi.com/journals/jnm/2015/686891/ Microbial fuel cells (MFCs), which can generate low-pollution power through microbial decomposition, have become a potentially important technology with applications in environmental protection and energy recovery. The electrode materials used in MFCs are crucial determinants of their capacity to generate electricity. In this study, we investigate the performance of using carbon nanotube (CNT) and graphene-modified carbon-cloth electrodes in a single-chamber MFC. We develop a process for fabricating carbon-based modified electrodes and Escherichia coli HB101 in an air-cathode MFC. The results show that the power density of MFCs can be improved by applying a coat of either graphene or CNT to a carbon-cloth electrode, and the graphene-modified electrode exhibits superior performance. In addition, the enhanced performance of anodic modification by CNT or graphene was greater than that of cathodic modification. The internal resistance decreased from 377 kΩ for normal electrodes to 5.6 kΩ for both electrodes modified by graphene with a cathodic catalyst. Using the modified electrodes in air-cathode MFCs can enhance the performance of power generation and reduce the associated costs. Hung-Yin Tsai, Wei-Hsuan Hsu, and Ying-Chen Huang Copyright © 2015 Hung-Yin Tsai et al. All rights reserved. Rare Earth Doped Apatite Nanomaterials for Biological Application Thu, 19 Mar 2015 07:56:47 +0000 http://www.hindawi.com/journals/jnm/2015/705390/ In most biological analyses, a sensitive detection technique is primarily dependent on the fluorescence labeling agent. New generation of fluorophores called rare earth doped apatite nanoparticle (REAnp) has the ability to emit near infrared radiations which are of low absorptivity by tissue chromophores and especially suitable for biological system imaging. Moreover, bioapatite is demonstrated to be an excellent candidate for biomedical applications because of its biocompatibility, biodegradability, and bioactivity. During recent years a lot of efforts have been made for achievement of REAnp for medical diagnostics and targeted therapeutics applications. In this review, we discuss the significance of REAnps in biological systems, different root of synthesis, and biological applications. Also we discuss the future studies for the effective biological applications of REAnps. Thalagalage Shalika Harshani Perera, Yingchao Han, Xiaofei Lu, Xinyu Wang, Honglian Dai, and Shipu Li Copyright © 2015 Thalagalage Shalika Harshani Perera et al. All rights reserved. Effects of Niobium-Loading on Sulfur Dioxide Gas-Sensing Characteristics of Hydrothermally Prepared Tungsten Oxide Thick Film Thu, 19 Mar 2015 07:32:40 +0000 http://www.hindawi.com/journals/jnm/2015/820509/ Nb-loaded hexagonal WO3 nanorods with 0–1.0 wt% loading levels were successfully synthesized by a simple hydrothermal and impregnation process and characterized for SO2 sensing. Nb-loaded WO3 sensing films were produced by spin coating on alumina substrate with interdigitated gold electrodes and annealed at 450°C for 3 h in air. Structural characterization by X-ray diffraction, high-resolution transmission electron microscopy, and Brunauer-Emmett-Teller analysis showed that spherical, oval, and rod-like Nb nanoparticles with 5–15 nm mean diameter were uniformly dispersed on hexagonal WO3 nanorods with 50–250 nm diameter and 100 nm–5 µm length. It was found that the optimal Nb loading level of 0.5 wt% provides substantial enhancement of SO2 response but the response became deteriorated at lower and higher loading levels. The 0.50 wt% Nb-loaded WO3 nanorod sensing film exhibits the best SO2 sensing performances with a high sensor response of ~10 and a short response time of ~6 seconds to 500 ppm of SO2 at a relatively low optimal operating temperature of 250°C. Therefore, Nb loading is an effective mean to improve the SO2 gas-sensing performances of hydrothermally prepared WO3 nanorods. Viruntachar Kruefu, Anurat Wisitsoraat, and Sukon Phanichphant Copyright © 2015 Viruntachar Kruefu et al. All rights reserved. Elaboration of Nanoparticles Containing Indomethacin: Argan Oil for Transdermal Local and Cosmetic Application Wed, 18 Mar 2015 06:59:30 +0000 http://www.hindawi.com/journals/jnm/2015/935439/ The objective of this work is the preparation of nanocapsules which are intended for the treatment of rheumatoid arthritis (RA). We use Argan oil as vehicle of hydrophobic drugs such as indomethacin. Nanoprecipitation technique was used like a method for preparation of nanocapsules, where polycaprolactone, acetone, and Argan oil are used as polymer, solvent, and carrier, respectively. Primarily, investigation of Argan oil amount addition was performed; then systematic study to optimize the formulation was done. Nanocapsules containing indomethacin (loaded nanocapsules) and others without indomethacin (blank nanocapsules) were characterized by studying particles size, zeta potential, and encapsulation efficiency. It is shown that particle size ranged between 290 nm and 350 nm. The zeta potential values were negative (from −40 up to −50 mV) while encapsulation efficiency ranged between 65 and 75%. Waisudin Badri, Karim Miladi, Rkia Eddabra, Hatem Fessi, and Abdelhamid Elaissari Copyright © 2015 Waisudin Badri et al. All rights reserved. Retracted: Restoration of Critical-Sized Defects in the Rabbit Mandible Using Autologous Bone Marrow Stromal Cells Hybridized with Nano-β-tricalcium Phosphate/Collagen Scaffolds Tue, 17 Mar 2015 14:13:14 +0000 http://www.hindawi.com/journals/jnm/2015/137312/ Journal of Nanomaterials Copyright © 2015 Journal of Nanomaterials. All rights reserved. Grown Low-Temperature Microcrystalline Silicon Thin Film by VHF PECVD for Thin Films Solar Cell Tue, 17 Mar 2015 13:51:07 +0000 http://www.hindawi.com/journals/jnm/2015/327596/ Hydrogenated microcrystalline silicon thin films can be used to fabricate stable thin film solar cell, which were deposited by very high frequency plasma-enhanced chemical vapor deposition at low temperatures (~200°C). It has been found that the obtained film presented excellent structural and electrical properties, such as high growth rate and good crystallinity. With the decreasing of silane concentration, the optical gap and the dark conductivity increased, whereas the activation energy decreased. A reasonable explanation was presented to elucidate these phenomena. In addition, we fabricated p-i-n structure solar cells using the optimum microcrystalline silicon thin films, and preliminary efficiency of 4.6% was obtained for 1 μm thick microcrystalline silicon thin film solar cells with open-circuits voltage of 0.773 V and short-circuits current density of 12.28 mA/cm2. Future scope for performance improvement lies mainly in further increasing the short-circuit current. Shanglong Peng, Desheng Wang, Fuhua Yang, Zhanguo Wang, and Fei Ma Copyright © 2015 Shanglong Peng et al. All rights reserved. Co3O4 Electrode Prepared by Using Metal-Organic Framework as a Host for Supercapacitors Tue, 17 Mar 2015 09:36:39 +0000 http://www.hindawi.com/journals/jnm/2015/192174/ Co3O4 nanoparticles were prepared from cobalt nitrate that was accommodated in the pores of a metal-organic framework (MOF) ZIF-8 (Zn(MeIM)2, MeIM = 2-methylimidazole) by using a simple liquid-phase method. Analysis by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that the obtained Co3O4 was composed of separate nanoparticles with a mean size of 30 nm. The obtained Co3O4 nanoparticles exhibited superior electrochemical property. Co3O4 electrode exhibited a maximum specific capacitance of 189.1 F g−1 at the specific current of 0.2 A g−1. Meanwhile, the Co3O4 electrode possessed the high specific capacitance retention ratio at the current density ranging from 0.2 to 1.0 A g−1, thereby indicating that Co3O4 electrode suited high-rate charge/discharge. Jiaqiang Jiang, Fuxiang Wei, Genxi Yu, and Yanwei Sui Copyright © 2015 Jiaqiang Jiang et al. All rights reserved. Interface-Induced Plasmon Nonhomogeneity in Nanostructured Metal-Dielectric Planar Metamaterial Tue, 17 Mar 2015 08:42:20 +0000 http://www.hindawi.com/journals/jnm/2015/876247/ Transformations of the electronic structure in thin silver layers in metal-dielectric (TiAlN/Ag) multilayer nanocomposite were investigated by a set of electron spectroscopy techniques. Localization of the electronic states in the valence band and reduction of electron concentration in the conduction band was observed. This led to decreasing metallic properties of silver in the thin films. A critical layer thickness of 23.5 nm associated with the development of quantum effects was determined by X-ray photoelectron spectroscopy. Scanning Auger electron microscopy of characteristic energy losses provided images of plasmon localization in the Ag layers. The nonuniformity of plasmon intensities distribution near the metal-nitride interfaces was assessed experimentally. A. I. Kovalev, D. L. Wainstein, A. Yu. Rashkovskiy, R. Gago, F. Soldera, J. L. Endrino, and G. S. Fox-Rabinovich Copyright © 2015 A. I. Kovalev et al. All rights reserved. Functionalization of Hollow Mesoporous Silica Nanoparticles for Improved 5-FU Loading Mon, 16 Mar 2015 12:42:54 +0000 http://www.hindawi.com/journals/jnm/2015/872035/ Hollow mesoporous silica nanoparticles were successfully fabricated and functionalized with appropriate silanes. After modifications, amine, carboxyl, cyano, and methyl groups were grafted onto the nanoparticles and all functionalized hollow mesoporous silica nanoparticles maintained a spherical and hollow structure with a mean diameter of ~120 nm and a shell thickness of ~10 nm. The loading capacity of the hollow mesoporous silica nanoaprticles to the anticancer drug, 5-fluorouracil, can be controlled via precise functionalization. The presence of amine groups on the surface of nanoparticles resulted in the highest loading capacity of 28.89%, due to the amine functionalized nanoparticles having a similar hydrophilicity but reverse charge to the drug. In addition, the change in pH leads to the variation of the intensity of electrostatic force between nanoparticles and the drug, which finally affects the loading capacity of amine functionalized hollow mesoporous silica nanoparticles to some extent. Higher drug loading was observed at pH of 7.4 and 8.5 as 5-fluorouracil becomes more deprotonated in alkaline conditions. The improved drug loading capacity by amine functionalized hollow mesoporous silica nanoparticles has demonstrated that they can become potential intracellular 5-fluorouracil delivery vehicles for cancers. Xiaodong She, Lijue Chen, Chengpeng Li, Canzhong He, Li He, and Lingxue Kong Copyright © 2015 Xiaodong She et al. All rights reserved. PVP Assisted Synthesis of Hydroxyapatite Nanorods with Tunable Aspect Ratio and Bioactivity Sun, 15 Mar 2015 13:58:06 +0000 http://www.hindawi.com/journals/jnm/2015/621785/ Highly crystalline and reasonably uniform hydroxyapatite (HA) nanorods were prepared by polyvinylpyrrolidone (PVP) assisted hydrothermal synthesis which produces high aspect ratio (length/width) nanorods. The aspect ratio of the nanorods was higher in the presence of PVP and increased with increasing concentrations of PVP. X-ray diffraction (XRD) analysis showed that the HA nanorods were of the hexagonal apatite phase. High resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) patterns confirmed that the nanorods grew in the c-axis direction (preferred orientation). The calculated lattice spacing was ~0.35 nm which is the c-axis value of hexagonal HA. Morphological variations of pristine and PVP added HA were evaluated by field emission scanning electron microscopy (FESEM) and TEM, which revealed that the presence of PVP greatly increased the aspect ratio of the HA nanorods. The formation mechanism of the PVP assisted HA was studied and a possible reaction model was given. Cell viability analysis by in vitro studies showed encouraging results for the high aspect ratio nanorods and indicated a possibility for tuning the activity based on controlling the aspect ratio. A. Joseph Nathanael, Young Ho Seo, and Tae Hwan Oh Copyright © 2015 A. Joseph Nathanael et al. All rights reserved. Influence of NH4Cl on Hydrothermal Formation of α-CaSO4·0.5H2O Whiskers Sun, 15 Mar 2015 13:16:52 +0000 http://www.hindawi.com/journals/jnm/2015/670872/ The influence of NH4Cl on hydrothermal formation of CaSO4·0.5H2O whiskers from CaSO4·2H2O precursor at 135°C was investigated in this paper. Compared with the blank experiment, the presence of 3 × 10−2 mol·L−1 NH4Cl led to the increase of the lengths of the whiskers from 50 to 160 μm to 150 to 300 μm and the decrease of the diameters from 1.0 to 1.5 μm to 0.2 to 0.5 μm. The dissolution of CaSO4·2H2O was accelerated by the complex interactions with NH4Cl and the soluble cations, which led to the decrease of the induction time for the occurrence of α-CaSO4·0.5H2O from 46 minutes to 34 minutes and the formation of CaSO4·0.5H2O whiskers with high aspect ratios. Furthermore the critical supersaturation for the formation of α-CaSO4·0.5H2O was investigated. Haoyuan Chen, Jing Wang, Sichao Hou, and Lan Xiang Copyright © 2015 Haoyuan Chen et al. All rights reserved. Laser-Assisted Synthesis of Mn0.50Zn0.50Fe2O4 Nanomaterial: Characterization and In Vitro Inhibition Activity towards Bacillus subtilis Biofilm Sun, 15 Mar 2015 13:11:14 +0000 http://www.hindawi.com/journals/jnm/2015/896185/ There is growing interest in the development of novel nanomaterials with potential antimicrobial activity and lesser toxicity. In the current research work, Mn0.5Zn0.5Fe2O4 nanoparticles were synthesized via a novel coprecipitation cum laser ablation technique yielding fine spinal structured material. The synthesized nanomaterial was structurally characterized by X-ray diffraction technique which confirmed the formation and the crystalline nature of Mn0.50Zn0.50Fe2O4 nanomaterial. The crystallite size determined by Debye-Scherrer’s formula was found to be ~12 nm. The formation of nanoparticles was evidenced by scanning electron microscopy. Energy dispersive X-ray analysis (EDXA) was performed for elemental analysis. The synthesized nanomaterial was interestingly found to be an effective antimicrobial agent and inhibited the growth of Bacillus subtilis biofilm formation. The 5 µg of Mn0.5Zn0.5Fe2O4 nanomaterial dissolved in 1 mL of DMSO showed excellent biofilm inhibitory activity 91.23% ± 1.87 against Bacillus subtilis. Shaukat Ali Shahid, Farooq Anwar, Muhammad Shahid, Nazia Majeed, Ahmed Azam, Mamoona Bashir, Muhammad Amin, Zahed Mahmood, and Imran Shakir Copyright © 2015 Shaukat Ali Shahid et al. All rights reserved. Functionalized Magnetic Nanoparticles and Their Effect on Escherichia coli and Staphylococcus aureus Thu, 12 Mar 2015 11:15:24 +0000 http://www.hindawi.com/journals/jnm/2015/416012/ Magnetite (Fe3O4) nanoparticles were prepared using coprecipitation and subsequently surface-functionalized with 3-aminopropyltriethoxysilane (APTS), polyethylene glycol (PEG), and tetraethoxysilane (TEOS). Nanoparticle morphology was characterized using scanning electron microscopy, while structure and stability were assessed through infrared spectroscopy and zeta potential, respectively. Average size of the nanoparticles analysed by dynamic light scattering was 89 nm, 123 nm, 109 nm, and 130 nm for unmodified magnetite and APTS-, PEG-, and TEOS-modified magnetite nanoparticles, respectively. Biological effect was studied on two bacterial strains: Gram-negative Escherichia coli CCM 3954 and Gram-positive Staphylococcus aureus CCM 3953. Most of modified magnetite nanoparticles had a significant effect on S. aureus and not on E. coli, whereas PEG-magnetite nanoparticles displayed no significant effect on the growth rate of either bacteria. Mohamed S. A. Darwish, Nhung H. A. Nguyen, Alena Ševců, and Ivan Stibor Copyright © 2015 Mohamed S. A. Darwish et al. All rights reserved.