Editorial
Hisatoshi Kobayashi; Mikael Syväjärvi
Abstract
Most of us are active in research and focus on the scientific issues and expert areas of our profession. Nanotechnology is recognized as potential arena which can have a profound societal impact. It includes all aspects important for innovation: technology sectors, value chains and business areas. However, ...
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Most of us are active in research and focus on the scientific issues and expert areas of our profession. Nanotechnology is recognized as potential arena which can have a profound societal impact. It includes all aspects important for innovation: technology sectors, value chains and business areas. However, it is still challenged in industrialization by the width of what may be considered as nanotechnology. It includes life science, semiconductors, communication, processors, textiles etc, and nanotechnology initiatives are facing the need to either boost arena or select niches. At the same time there are rural challenges, and we need to meet to propose paths for solutions.
Research Article
Pramod K Nampoothiri; Mayuri N Gandhi; Ajit R Kulkarni
Abstract
The luminescence at the absorption maximum of c-Si solar cells (1002 nm) of Ytterbium (3+) ions (Yb3+) make them a suitable candidate for solar spectrum converting material for c-Si solar cell. In this work oleic acid functionalized lanthanum fluoride (OA-LaF3) nanoparticles doped with Nd3+, Yb3+ (2-5 ...
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The luminescence at the absorption maximum of c-Si solar cells (1002 nm) of Ytterbium (3+) ions (Yb3+) make them a suitable candidate for solar spectrum converting material for c-Si solar cell. In this work oleic acid functionalized lanthanum fluoride (OA-LaF3) nanoparticles doped with Nd3+, Yb3+ (2-5 nm) were synthesized by coprecipitation method in which Nd3+ (Neodymium (3+) ions) acts as the sensitizer for Yb3+. The oleic acid chemisorption on LaF3 nanoparticles was confirmed by FTIR and TGA analysis. OA-LaF3: Nd3+ Yb3+ nanoparticles (Nd3+ -10 mol%, Yb3+-0 to 20 mol% ) luminescent at 880 nm, 1053 nm, 1325 nm (Nd3+ ions) and 1002 nm (Yb3+ ions) was observed for excitation at 575 nm. The excitation spectra for the Yb3+ emission from OA-LaF3: Nd3+ Yb3+ showed all the excitation peaks of Nd3+ in the visible region. This confirmed the energy transfer from Nd3+ to Yb3+ ions. The increase in the Yb3+ emission intensity at 1002 nm was observed as Yb3+ dopant concentration increased from 0 to 5%. Above 5% of Yb3+ doping concentration, Yb3+ luminescence was observed to be decreasing, which was attributed to the concentration quenching. Copyright © 2017 VBRI Press.
Research Article
Shahjad .; Ranoo Bhargav; Dinesh Bhardwaj; Asit Patra
Abstract
Currently significant progress has been made for the small molecules, indeed, achieved comparable performance compared to polymer in electronic devices mainly due to the many advantages of small molecules over the polymers. Designing better small molecules for electronic applications are required a comprehensive ...
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Currently significant progress has been made for the small molecules, indeed, achieved comparable performance compared to polymer in electronic devices mainly due to the many advantages of small molecules over the polymers. Designing better small molecules for electronic applications are required a comprehensive understanding of the structure-properties relationship and the factors affecting it. Valuable information can be generated directly toward understanding by systematically theoretical and experimental studies (band gap, HOMO, LUMO energy levels and geometry). Hybrid density functional B3LYP level of theory is a very good method for predicting the reliable geometry, electronic structure and properties of conjugated systems. In the present work, we have calculated the band gaps, highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and geometry of a series of small molecules based on oligothiophene, benzodithiophene and dithienosilole unit using the hybrid density functional (B3LYP/6-31G(d)) level of theory and correlated with experimental values. The study provides details for the effect of the extended conjugation, two-dimension conjugation, substitution on geometry, HOMO, LUMO and band gaps of the small molecules. Copyright © 2017 VBRI Press.
Research Article
Nandini Sharma; Ranjana Jha
Abstract
Zinc oxide nanoparticles were synthesized utilizing a green and simple sonochemical route. The synthesized ZnO nanoparticles were characterized for the analysis of structural and optical properties. Characterization with XRD and TEM shows that the synthesized particles were uniformly distributed, crystalline ...
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Zinc oxide nanoparticles were synthesized utilizing a green and simple sonochemical route. The synthesized ZnO nanoparticles were characterized for the analysis of structural and optical properties. Characterization with XRD and TEM shows that the synthesized particles were uniformly distributed, crystalline in nature with spherical shape and narrow size distribution of particles (48-50 nm). UV-Vis and PL spectra shows optical band gap to be 3.5 eV and ZnO sample possess fewer defect states. ZnO nanoparticles synthesized shows good optical properties and was observed to be a promising candidate to be used in thin film solar cells. Copyright © 2017 VBRI Press.
Research Article
Manmath Kumar Dash; T. Karthikeyan; S. Saroja
Abstract
Chromium alloyed Ferritic/Martensitic steels are widely used as structural materials in power plants, and considered for core applications of fast and fusion reactors. Characterization and fundamental interpretation of deformed microstructure through crystal plasticity principles are useful for tailoring ...
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Chromium alloyed Ferritic/Martensitic steels are widely used as structural materials in power plants, and considered for core applications of fast and fusion reactors. Characterization and fundamental interpretation of deformed microstructure through crystal plasticity principles are useful for tailoring desired microstructure by optimal processing methods. This study reports the characterization of plastic strain distribution in cold rolled 9Cr-1Mo steel using Electron back scatter diffraction (EBSD) technique. Small orientation changes within the individual grains were studied to gauge the accumulation of ‘geometrically necessary’ dislocations in deformed material, and correlate with the load geometry. The correlated misorientation angle distribution showed a significant presence of low angle boundaries in the deformed microstructure as compared to the annealed specimen. Crystal orientation map of deformation bands indicated significant intra-grain rotation, and the extent of rotation was distinctly different for different grains. A heterogeneous accumulation of plastic strain distribution is inferred from the grain maps of local misorientation angle (0.5º-5º) and orientation spread parameters. Analysis by Schmid factor criteria (0.4-0.5) showed more than 50% of the grains to exhibit favorable orientation for {110} <111> slip activity, whereas higher stress would be required for plastic deformation of remaining grains. Copyright © 2017 VBRI Press.
Research Article
Nandeibam Nilima; Mamata Maisnam; Sumitra Phanjoubam
Abstract
Li-Ni-Co ferrite/SiO2 composites with representative formula Li0.41Ni0.1Co0.08Fe2.41O4+ xSiO2 (i.e., x = 0wt. %, 5wt. %,10wt. % and 20wt. %) were prepared by sol-gel method. The prepared composites were pre-sintered at 600ºC for 2 hrs and then finally sintered at 1000ºC for 6 hrs. X-ray diffraction ...
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Li-Ni-Co ferrite/SiO2 composites with representative formula Li0.41Ni0.1Co0.08Fe2.41O4+ xSiO2 (i.e., x = 0wt. %, 5wt. %,10wt. % and 20wt. %) were prepared by sol-gel method. The prepared composites were pre-sintered at 600ºC for 2 hrs and then finally sintered at 1000ºC for 6 hrs. X-ray diffraction studies showed diffraction peaks indicating single phase with spinel structure. However, peaks of SiO2 were found in composites of higher (x). The microstructure of the samples was studied by using Scanning Electron Microscopy. The crystallite size and average grain size were found to decrease with increase of SiO2 content. The room temperature frequency variation of dielectric constant and dielectric loss was measured from 100Hz-1MHz and they showed a dispersive behavior. The variation has been explained by Verwey mechanism of electron hopping and Koop’s two-layer model. The addition of SiO2 plays significant role in influencing the various structural, microstructural and electrical properties. Uniform and refined microstructures are observed with the addition of SiO2 and this reduces the value of dielectric constant and loss significantly, which is desirable for high frequency applications. The results obtained and mechanisms involved are discussed. Copyright © 2017 VBRI Press.
Research Article
Shobhna Choudhary; Ram J. Sengwa
Abstract
The dielectric and electrical spectra of solution cast prepared nanocomposite films comprising poly(vinyl alcohol) (PVA) as polymer matrix and zinc oxide (ZnO) as inorganic nanofiller (PVA–x wt% ZnO (x = 0, 1, 3 and 5)) have been investigated in the frequency range from 20 Hz to 1 MHz. Anomalous ...
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The dielectric and electrical spectra of solution cast prepared nanocomposite films comprising poly(vinyl alcohol) (PVA) as polymer matrix and zinc oxide (ZnO) as inorganic nanofiller (PVA–x wt% ZnO (x = 0, 1, 3 and 5)) have been investigated in the frequency range from 20 Hz to 1 MHz. Anomalous increase is observed in real part of complex permittivity with increase of ZnO concentration, whereas relaxation peak corresponding to PVA chain segmental motion is appeared in the intermediate frequency region of dielectric loss tangent and the loss part of electric modulus spectra of the nanocomposites. These results confirm that the interaction of ZnO nanoparticles with hydroxyl groups of PVA acts as exciter for polymer chain segmental dynamics in the nanocomposites. The temperature dependent dielectric investigations on PVA–3 wt% ZnO film reveal that the dielectric polarization and chain segmental dynamics increase with the increase of temperature. The dielectric relaxation and conductivity activation energies values of the film are determined from the Arrhenius relation, which are found equal. The X-ray diffraction study confirms that the crystalline phase of PVA matrix abruptly reduces with doping of only 1 wt% ZnO which suggests that the interaction of polymer-nanoparticles significantly alter the hydrogen bonded crystalline structure of pristine PVA matrix. The dielectric and electrical results showed that these nanodielectrics are potentially useful as an electrical insulation material for various electronic devices. Copyright © 2017 VBRI Press.
Research Article
Ishwar Naik; Rajashekhar Bhajantri; Sunil Rathod; Jagadish Naik
Abstract
In the present work, spin coated thin films of P3HT: NTCDA donor- acceptor blends of weight ratios 3:1, 1:1 ,1:3 are prepared in Toluene using the self-made spin coating machine. The experiment is focused to optimize the P:N weight ratio of the photoactive blend that can absorb maximum solar energy and ...
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In the present work, spin coated thin films of P3HT: NTCDA donor- acceptor blends of weight ratios 3:1, 1:1 ,1:3 are prepared in Toluene using the self-made spin coating machine. The experiment is focused to optimize the P:N weight ratio of the photoactive blend that can absorb maximum solar energy and also to enhance the absorption by doping it with gold nano particles. Absorption property of the samples are studied using JASCO UV VIS 670 spectrometer which shows that 1:3 blend has the broad spectral response and considered to be the best active blend. The optical band gaps of the samples are determined through Tauc’s plot, wherein the onset wavelength for 1:3 sample is found to be 660nm with a band gap of 1.87 eV. The optimized 1:3 blend is doped with gold nano-particle dispersion in citrate buffer. The absorbance gets increased on doping with nano particle with extremely broadened spectral response which is attributed to the Localized Surface Plasmon Resonance(LSPR). Photons are trapped by the gold particles in the polymer matrix for the efficient harvesting of the solar energy. The construction of the solar cell using this Plasmon enhanced photoactive material is the work under progress. Copyright © 2017 VBRI Press.
Research Article
Kartick Prasad Dey; Sumit Mishra
Abstract
In this article, we have reported the synthesis of Polyacrylamide grafted Barley (Ba-g-PAM) by free radical copolymerization technique. Ceric ammonium nitrate (CAN) was used as a free radical initiator for this synthesis process. Various grades of Ba-g-PAM were synthesized by varying the CAN and AM concentration. ...
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In this article, we have reported the synthesis of Polyacrylamide grafted Barley (Ba-g-PAM) by free radical copolymerization technique. Ceric ammonium nitrate (CAN) was used as a free radical initiator for this synthesis process. Various grades of Ba-g-PAM were synthesized by varying the CAN and AM concentration. The swelling properties of these different grades of Ba-g-PAM were performed in different pH media like 1.2, 6.8& 7.4 at 250C and 370C. All grades showed better swelling properties at 370C than 250C. The matrix tablets of different grades of grafted materials were prepared by following the standard protocol using 5-flurouracil as a model drug. The swelling and erosion property of each matrix tablet was performed at 370C in different pH media like 1.2, 6.8& 7.4. The percentage of drug released from different matrix tablets was determined in different pH media like 1.2, 6.8& 7.4 (similar to GI tract). The drug release kinetics was also determined with the help of percentage drug release results. The matrix tablet of best grade i.e. Ba-g-PAM5 follows non-fickian kinetics, so, the diffusion rate of drug from matrix tablet and the relaxation rate of the polymer chains in the matrix tablets are comparable. The acute oral toxicity test was performed on the basis of Organization of Economic Co-operation and Development (OECD) guidelines, showing non-toxic behavior. The above results support that the controlled release of5-flurouracil in the colonic region has been successfully carried out. This developed material may be of help in the colon cancer treatment. Copyright © 2017 VBRI Press
Research Article
Ajay S. Utiye; Sanjay Kumar Awasthi; S. K. Bajpai; B. Mishra
Abstract
The method of preparation of Gelatin/poly (aniline) composite films has been discussed. Gelatin was cross linked with glyoxal (Glox) in aqueous medium. The composite film was prepared by in-situ polymerization of Aniline within the Gelatin film matrix. The films so prepared have been characterized with ...
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The method of preparation of Gelatin/poly (aniline) composite films has been discussed. Gelatin was cross linked with glyoxal (Glox) in aqueous medium. The composite film was prepared by in-situ polymerization of Aniline within the Gelatin film matrix. The films so prepared have been characterized with XRD, tensile testing and conductivity measurements. The variation in mechanical/electrical properties of Gelatin/poly(aniline) composite films with varying concentration of aniline have been investigated. It was observed that the electrical conductivity of the films increase appreciably with the concentration of aniline in the film. In addition, the tensile strength of the films was also found to increase with aniline concentration. The results from XRD, conductivity test and tensile testing were correlated. A stronger material having added advantage of conductivity has been reported. Copyright © 2017 VBRI Press.
Research Article
Neha Sharma; K. Prabakar; S. Ilango; S. Dash; A. K. Tyagi
Abstract
AIN thin films were grown by ion beam sputter deposition in reactive assistance of N+/N2+ ions on Si (100) substrates. During deposition, assisted ion energy (EA) was varied as 90 eV and 120 eV with a post deposition exposure to N2 plasma. The resultant films were characterized by grazing incidence x-ray ...
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AIN thin films were grown by ion beam sputter deposition in reactive assistance of N+/N2+ ions on Si (100) substrates. During deposition, assisted ion energy (EA) was varied as 90 eV and 120 eV with a post deposition exposure to N2 plasma. The resultant films were characterized by grazing incidence x-ray diffraction (GIXRD) for their structure and atomic force microscopy (AFM) for their root mean square (rms) surface roughness (δ). UV-VIS spectrophotometry was carried out to explore their optical band-gap with associated Urbach (EU) and weak absorption tail (EWAT) energies. Our results show that, AlN thin film grown with 90 eV reactive ion assistance possesses larger optical band gap (Eg) of 5.3 eV associated with comparatively narrower band tails when compared to those AlN thin film samples which were grown for 120 eV reactive ion assistance. These optical band-gaps are further correlated with corresponding Urbach energy tails which can be used as a measure of disorder in microstructure of the film. Also, appropriate optimization of energy tails substantiates the possibility of band gap engineering as per the requirement of different thin film devices. Copyright © 2017 VBRI Press.
Research Article
Ujjal Chowdhury
Abstract
Room temperature multiferroicity has been in the centre of interest for last few years due to its enormous potential to be applied as real multifunctional device. LuFeO3 is a potential candidate as room temperature multiferroic1, which offers strong multiferroic coupling at room temperature [1]. Presence ...
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Room temperature multiferroicity has been in the centre of interest for last few years due to its enormous potential to be applied as real multifunctional device. LuFeO3 is a potential candidate as room temperature multiferroic1, which offers strong multiferroic coupling at room temperature [1]. Presence of ferroelectric polarization is observed in Mn-doped LuFeO3 also. The main area of restriction is its low polarization, which is to be improved before it can be applied in real devices. In order to do that proper understanding of the mechanism of generation of ferroelectricity is needed. In order to do that we observed that, the ferroelectric and multiferroic properties at room temperature, in orthorhombic distorted perovskite LuFeO3 are greatly affected by Cu or Mn doping. If we replace Fe+3 ion (Ionic Radius=126) with some amount another ion of increasing ionic radius Mn+2 (Ionic Radius=127) and Cu+2 (Ionic Radius = 128) the ferroelectric properties are greatly affected as evidenced by the P-E Hysteresis loop measurements. The appearance of ferroelectricity in LuFeO3 could be attributed to the spin current based model as proposed by katsura et al. [3]. The effect of Cu and Mn doping also can be explained with the Spin current based model [3]. Copyright © 2017 VBRI Press.
Research Article
Pawan K. Kaul; A. Joel Samson; I V M V Enoch; Paulraj Mosae Selvakumar
Abstract
In this report, we have explored the thermal stability and flammability of unsaturated polyester resin (UP) nano-composites blended with flame retardant trixylenyl phosphate (TXP) and nano-filler dodecyl sulphate intercalated magnesium aluminum layered double hydroxide (MgAlDS LDH). MgAl LDH was synthesized ...
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In this report, we have explored the thermal stability and flammability of unsaturated polyester resin (UP) nano-composites blended with flame retardant trixylenyl phosphate (TXP) and nano-filler dodecyl sulphate intercalated magnesium aluminum layered double hydroxide (MgAlDS LDH). MgAl LDH was synthesized by co-precipitation method and anion dodecyl sulphate was intercalated by ion exchange method. The XRD analysis denoted the presence of layered double hydroxide crystal lattice which supports the structural conformation. The IR spectra of trixylenyl phosphate (TXP), MgAl LDH and MgAlDS LDH depicted their relevant vibrational transitions. The nano-composites of unsaturated polyester, crossed linked with styrene, were prepared by mixing varying proportions of TXP and MgAlDS LDH. The XRD of the composites reveal the exfoliation of MgAlDS LDH in polymer matrix, which enhances the thermal stability of nano-composite containing 1% MgAlDS LDH along with TXP than the polymer containing TXP alone, was shown by TGA. The Unsaturated polyester (UP) resin nano-composite decomposes by two stages. There was 8% reduction in peak mass loss rate of nano-composite containing 1% MgAlDS LDH along with TXP in comparison to nano-composite containing only TXP. UL-94 study shows that MgAlDS LDH had flame retardant properties as confirmed by reduction of burning rate in comparison to virgin unsaturated polyester resin. Morphology analysis by SEM on Charred residue of nanocomposite containing 23% TXP and 1% MgAlDS LDH has shown more compact, hard and without any pin holes upper layer than nanocomposite containing only 24% TXP alone. This can be used in preparation of flame retardant articles of unsaturated polyester resin and will allow use of unsaturated polyester on places where it is avoided due to high flammability and low thermal stability. Copyright © 2017 VBRI Press.
