Issue 6

Conference Report Of ICMTech – 2016, India

Ashutosh Tiwari

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 419-420
DOI: 10.5185/amlett.2016.6001

Vinoba Bhave Research Institute (VBRI) organized a four day International Conference on Materials Science & Technology (ICMTech-2016) from 01 - 04 March, 2016 on the occasion of their silver jubilee establishment in Delhi, India. VBRI provides research and innovation leadership in rural technology and sustainable developments maintaining core and shared facilities, vocational training, rural entrepreneurship activities and fostering collegial exchanges of international expertise. 

Improvements In Electronic Structure And Properties Of Graphene Derivatives

Velram Balaji Mohan; Manfred Stamm;Debes Bhattacharyya; Dongyan Liu; Krishnan Jayaraman

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 421-429
DOI: 10.5185/amlett.2016.6123

This article focuses on the reduction of graphene oxides using different reductants and conditions systematically varying the chemical and physical structure, surface topography and chemistry and film thickness of reduced graphene oxide (rGO) films, with a focus on how these influence the property of most interest: electrical conductivity. The reduction process restores graphene oxide to a graphene-like structure, improving electrical conductivity while creating changes such as increased roughness, film thickness and new surface functionality. Films with smooth surfaces and minimal thicknesses have been shown to possess higher electrical conductivity. There have been minor changes in d-spacing and improvements in crystal perfection and orientation could be concluded from XRD patterns. Through XPS analysis, a significant decrease in the amount of oxygen functional groups at the surface has been noticed as the films get thinned. 

Thermally Activated And Field Dependent Hole Transport In Poly(3-hexylthiophene)

Ranoo Bhargav; Asit Patra; Suresh Chand

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 430-435
DOI: 10.5185/amlett.2016.5991

Here, we investigate the hole transport mechanism in poly(3-hexylthiophene) (P3HT). First, ohmic contact has been established at indium tin oxide (ITO)/P3HT interface by molybdenum oxide (MoOx) hole injection layer. Thickness of MoOx layer is observed to play a crucial role with ohmic contact being observed even for 1 nm layer. However, device with less than 5 nm layer are found to be extremely unstable. A device with a 5 nm layer of MoOx is found to be stable and ohmic injection at ITO/P3HT layer enabled to observe ohmic conduction at low voltages (< 3 V), trap free space charge limited conduction (SCLC) for > 3 V. At higher voltages, effect of field on charge carrier mobility is also observed. Observation of SCLC enabled us to directly evaluate the hole mobility in P3HT which is calculated to be 5.4 × 10 -5 cm 2 /Vs. Conductivity is calculated from the low voltage region and found to be 6.85 × 10 -8 S/cm. Temperature dependent mobility is used to study the charge transport behavior and it has been observed that mobility is thermally activated with an extremely low activation energy of 39 meV. 

Electrical Characterization Of Pr3+ Containing Lithium Borate Glasses By Impedance Spectroscopy

D. D. Ramteke; H. C. Swart; R. S. Gedam

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 436-440
DOI: 10.5185/amlett.2016.6329

The role Pr 3+ ions in the lithium borate glasses have been investigated by electrochemical impedance spectroscopy technique. The glasses were prepared by conventional melt quench technique with formula 27.5 Li2O-(72.5-X) B2O3-X Pr6O11 (where, X= 0.5, 1, 1.5 and 2). It is observed that the conductivity of the glasses decreases with the addition of Pr 3+ ions which was correlated with increase in the activation energy of the glasses. The observed conductivity behavior in the present study is mostly govern by the Pr 3+ as it has higher molecular weight as compared to other component in the glass system. Insight of conduction mechanism was revel by the scaling of modulus and conductivity data of the prepared samples. Scaling confirms that the conduction mechanism is compositional dependent. Based on the present study it is possible to use and modified these glasses as an insulating and dielectric material.

 Preparation And Electrochemical Characterization Of PANI/PVA And PANI/Zr/PVA Composites For Supercapacitor Application

Tatiana N. Myasoedova; Eugeniya N. Shishlyanikova; Tatiana A. Moiseeva; Maria Bzerzinskaya

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 441-444
DOI: 10.5185/amlett.2016.6074

In the present work, the PANI and PANI/Zr composite powders were synthesized by the method of chemical polymerization in the inorganic acid medium. The morphology of prepared composites demonstrates fiber-like structure revealed by scanning electron microscopy. The value of the specific surface area estimated by the BET technique depends on the type of the composite powder and was found to be 66.8 and 142.05 m 2 /g for PANI and PANI/Zr respectively. UV–Vis spectroscopy was employed to characterize the optical properties of the synthesized powder composites. The incorporation of zirconium gives rise to the red shift of π– π* transition of pristine PANI. The synthesized composite powders were used for preparation of PANI/PVA and PANI/Zr/PVA composites which electrochemical properties were compared in different electrolytes: 0.5 M KOH, 0.5 M NaCl and 0.5 M H2SO4. Excellent electrochemical reversibility was found out for both PANI/PVA and PANI/Zr/PVA composites. Effect of electrolyte type and current value on the specific capacitance of the prepared composites was observed. 

Structure Dependent Room Temperature Ferromagnetism In Co, Nb Co-doped BaTiO3 Thin Films Prepared By RF Sputtering

R. Siddheswaran; Petr Nov

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 445-448
DOI: 10.5185/amlett.2016.6183

Thin films of BaTiO3 and Co, Nb co-doped BaTiO3 on glass and Si (100) substrates were deposited by RF sputtering (at 350 ºC), and annealed. The amorphous and crystalline phases were observed for the as-deposited and annealed samples, respectively from the X-ray diffraction (XRD) studies. The magnetic behaviour of the pure and doped BaTiO3 films was studied by vibrating sample magnetometry (VSM). In this study, the ferromagnetic behaviour at room temperature was observed in the Co, Nb co-doped BaTiO3 of both amorphous and crystalline films. The annealed polycrystalline Co, Nb co-doped BaTiO3 films have the larger saturation magnetization and coercivity than the amorphous films. The room temperature ferromagnetic responses were also observed by the Magneto-optical Kerr effect (MOKE) measurements for both as-deposited and annealed samples. 

Synthesis And Characterization Of Ring Shaped Spermine Mediated Nanogold Assemblies At The Air Water interface

Divya Sachdev; Sandeep Singh;Renu Pasricha; Shweta Gupta; Veeresh Kumar

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 449-455
DOI: 10.5185/amlett.2016.6036

Surface tension mediated U-shaped interlinked diammine network (spermine) assembled at the air-water interface, when interacted with aqueous functionalized gold nanoparticles (AuNPs), form ring like nanogold structures. These electrostatic force guided self-assembies of the ligand diammine with gold provides a facile route for control on the nanostructure formation while portraying double linkage ability of the diammine (here spermine). Pressure-area isotherm of controlled multilayer formation of spermine linked gold NPs (spermine-AuNPs) were studied and characterized by UV-vis spectroscopy, Fourier transform infrared spectroscopy and Transmission electron microscopy (TEM). The TEM micrographs clearly elucidate the formation of ring like networks of gold NPs under the influence of spermine. Furthermore we believe that these spermine-AuNPs will surely have supportive role as a bio-diagnostic material for ultra-sensitive biological detection and pave way for a novel route for assembly fabrication. 

Comparison Studies Of SiO2 and HCl-SiO2 Filler On The Film Formation And Ionic Conductivity Of PMMA/ENR 50 Electrolytes

Sharil Fadli Mohamad Zamri; Famiza Abdul Latif; Siti Izzati Husna Mohd Azuan; Ab Malik Marwan Ali; Ruhani Ibrahim; Norashima Kamaluddin; Fitrah Hadip

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 456-460
DOI: 10.5185/amlett.2016.6125

In this study, polymer electrolytes derived from polymethyl methacrylate/50 % epoxidized natural rubber (PE) were successfully prepared. The effects of silicon dioxide (SiO2) (15 nm) and acid modified SiO2 (HCl-SiO2) (15 nm) on the film formation and ionic conductivity of polymer electrolytes were investigated. In samples preparation, SiO2 was used as received. Meanwhile, HCl-SiO2 was prepared by reacting SiO2 with 7 M of hydrochloric acid (HCl) solution. PE, PE filled with SiO2 (PE-SiO2) and PE filled with HCl-SiO2 (PE-HCl-SiO2) electrolytes were prepared by solvent casting method with tetrahydrofuran (THF) as solvent and lithium tetrafluoroborate (LiBF4) as doping salt. The smoothness surface, opacity and agglomeration of PE-HCl-SiO2 film were found in between PE and PE-SiO2. CHNS analysis shows that the percentage of hydrogen in HCl-SiO2 and SiO2 are 0.88 and 2.07 %, respectively. Fourier transform infra-red (FT-IR) analysis confirm that HCl-SiO2 has low number of silanol group (Si-OH) but high number of siloxane group (Si-O-Si) compared to SiO2. Field Emission Scanning Electron Microscopy (FESEM) analysis shows that HCl-SiO2 has smaller size of agglomeration and porosity compared to SiO2. Meanwhile, electrochemical impedance spectroscopy (EIS) analysis shows that the ionic conductivity of  PE-HCl-SiO2 is higher than PE but slightly lower than PE-SiO2. 

Poly(3, 4-ethylene Dioxythiophene) Grafted Multiwalled Carbon Nanotube Decorated Polyurethane Foam For Antistatic And EMI Shielding Applications

M. Farukh;S.K.Dhawan

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 461-466
DOI: 10.5185/amlett.2016.6011

The paper reports the designing of PEDOT grafted PU foam by in-situ emulsion polymerization of ethylene dioxy thiophene (EDOT) on polyurethane foam (PU) containing multi-walled carbon nanotube (MWCNT) and by coating PEDOT on PU foam and to study their antistatic and electromagnetic shielding behavior. Static decay time measurements reveal that PEDOT grafted PU foam shows static decay time ranging from 0.17 sec to 0.75 sec on going down from 5000 v to 500 volts. EMI shielding measurement of the foam in Ku-band shows a shielding attenuation of 8-10 dB which indicates that that the foam can find applications as antistatic encapsulation material in electronic packaging of high tech equipments. SEM studies of the foam shows a uniform coating of PEDOT on PU foam leading to better conductivity of the conducting foam which accounts for its better anti-static properties.

Nano Sized Fe Doped Strontium Titanate For Photocatalytic Degradation Of Dibutyl Phthalate Under Visible Light

Husien A. Abbas; Tarek S. Jamil

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 467-471
DOI: 10.5185/amlett.2016.6146

Nano-sized SrTiO3 and SrTi0.7Fe0.3O3 photocatalysts were prepared by the complex route precursor method. The prepared photocatalysts were characterized by XRD, TEM, XPS and diffuse reflectance. The effect of iron doping on the structural properties and the photocatalytic activity was studied. All the prepared samples have single cubic perovskite structure. It was found that doping of SrTiO3 with Fe shifted the peak positions toward higher 2θ value, decreased both the cubic lattice parameter and the unit cell volume, decreased the average crystallite size of SrTiO3 from 53 nm to 35 nm and shifted the absorption to the visible light range (red shift). The photocatalytic degradation activity of 30 mole % Fe doped SrTiO3 was significantly improved the degradation of dibutyl phthalate in 90 minutes under visible light irradiation by 4 times higher than SrTiO3. 

Enhanced Electrochemical Performance Of Xanthine Biosensor By Core - Shell Magnetic Nanoparticles And Carbon Nanotube Interface

Utkarsh Jain; Jagriti Narang;Nidhi Chauhan

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 472-479
DOI: 10.5185/amlett.2016.5985

Xanthine oxidase (XOD) was extracted from bovine milk. Immobilization of extracted XOD was performed by covalently N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxy succinimide (NHS) chemistry on core–shell magnetic nanoparticles (MNPs)/carboxylated multiwalled carbon nanotube (c-MWCNT) composite film. The film was electrodeposited on glass plate electrode (usually the surface of fluorine doped tin oxide (FTO). In order to characterize nanocomposite modified FTO electrode, various methods including scanning electron microscopy (SEM), cyclic voltammetry (CV), Fourier transform infrared (FTIR), and electrochemical impedance spectroscopy (EIS) were performed. These methods were evaluated prior and following XOD immobilization. The working optimal conditions for instance 30 °C, +0.2 V vs. Ag/AgCl, sodium phosphate buffer at pH 7.0 were attributed for developing this biosensor. The linearity of the response upto 150 μM xanthine concentration, 0.05 μM (S/N = 3) detection limit and a response time within 3 s were obtained. The biosensor was stored at 4 °C and used above 100 times for a long period of 120 days. The loss of 50 % of activity was noticed. This fabricated biosensor was then employed determining xanthine in fish meat sample.

Theoretical Survey Of Luminescence Observed In Nanostructured Silicon Rich Oxide Films Attributed To annealing Processes

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 480-484
DOI: 10.5185/amlett.2016.6312

The motivation of this work is to apply a new model, which we had called the Global Reactions Model (GRM), for the theoretical study of the optical and electronics properties of Silicon Rich Oxides (SRO) structures regardless of the technique used to fabricate such structures. Recently we published the Global Reactions Model (GRM) to describe a set of chemical reactions that could hypothetically occur during the process of obtaining silicon rich oxide (SRO) films, notwithstanding of the technique used to grow such films. Particularly, chemical reactions that occur during the process of growing of SRO films by Low Pressure Chemical Vapor Deposition (LPCVD) and Hot Filament Chemical Vapor Deposition (HFCVD) techniques were emphasized in these models. We suggest and evaluate either some types of molecules or resulting nanostructures and we have predicted theoretically, by applying the density functional theory (DFT), the contribution that they may have to the phenomenon of luminescence. We calculated the luminescent spectra of the as grown and the annealed structures. In this work we focused in siloxanes species presumably found in SRO. 

Enhanced Optical Absorbance Of Hydrophobic Ti Thin Film: Role Of Surface Roughness

Jyoti Jaiswal; Manpreet Singh;Ramesh Chandra; Amit Sanger; Ashwani Kumar; Satyendra Mourya; Samta Chauhan; Ritu Daipuriya

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 485-490
DOI: 10.5185/amlett.2016.6056

In the present work, structural, morphological, optical and wettability properties of DC magnetron sputtered titanium (Ti) thin films have been investigated. The nanostructured Ti thin films were deposited on glass and silicon substrates at various deposition angles, θD = 0°, 30°, 45° and 60°. HCP structure of Ti thin films with preferred peak orientations (100) and (002) were revealed from XRD. It was observed that as the deposition angle increases, film thickness (~260 - 100 nm) as well as average crystallite size (~27 - 11 nm) of Ti thin films decrease. Significant changes in topography of the films, with change in deposition angle, have been observed. The optical and wettability results suggested that transmission, reflection, absorption and water contact angle of Ti thin films are strongly influenced by deposition angle due to change in its surface roughness. The large near infrared (NIR) absorbance (~ 66 - 75%) was found for the sample deposited at θD = 30°, which exhibited hydrophobic (~ 94.6°) nature with high surface roughness (~ 28 nm). 

Influence Of Hybridization On The Performance Of Glass Composites Under Low And High Velocity Impact

T. Sreekantha Reddy; P. Rama Subba Reddy; V. Madhu

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 491-496
DOI: 10.5185/amlett.2016.6316

Hybrid composites find applications in many advanced fields that include aerospace and armour due to their high specific strength and high energy absorption capacity. The present study has attempted to develop cost effective E and S2 glass based hybrid composites for armour applications in order to get advantages of both fibres i.e superior impact properties at reduced cost. Three hybrid composites based on E glass and S2 glass in the volume ratios of 75:25, 50:50 and 25:75 were fabricated using epoxy matrix. Low velocity impact (60-110 J energy) experiments using instrumented drop tower on 2 mm thickness laminates show that composites perform better when impacted on E glass strike face than on S2 glass strike face. Hybrid composite made of 25% E glass and 75 % S2 glass (ES 25-75) has shown equal performance to that of 100 % S2 glass/epoxy (S 100) laminate. Ballistic evaluation on 6 mm thick laminates against 7.62 mm mild steel projectile also prove that the performance of hybrid composites increases with increase in S2 glass content and ES 25-75 composite performs similar to S 100 laminate in terms of energy absorption as well as damage volume.

Investigation Of Dosimetric Features Of Beta – Irradiated Er3+ Doped Strontium Pyrophosphate

Nimesh P. Patel; M. Srinivas; Vishwnath Verma; Dhaval Modi; K. V. R.Murthy

Advanced Materials Letters, 2016, Volume 7, Issue 6, Pages 497-500
DOI: 10.5185/amlett.2016.6160

Thermoluminescence (TL) of Sr2P < sub>2O7: Er 3+ phosphors had been studied in order to investigate the nature of the trapping centers created due to doping ions. The effect of beta – irradiation was analyzed for various doses given to the samples. The measurements of TL glow curves have been done at the heating rate 6 K/s. The TL measurements done for the study of the dosimetric properties of samples showed that the β-dose response is linear from 5 Gy to about 50 Gy. The experimental glow curves had been analyzed by glow curve fitting technique which revealed that the glow curve is consist of three curves with peak temperature 400 K, 430 K and 464 K. The activation energy ‘Ea’ of the peaks had been calculated to be 0.90 ± 0.03 eV, 1.10 ± 0.04 eV and 1.05 ± 0.03 eV, respectively. The geometrical factor ‘μg’ having values 0.51, 0.52 and 0.48, imply that the glow curve having second order kinetics. The linear dose response, fading effect after exposed and reusability of samples are very reliable for dosimetry applications.