Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Centre for Nanotechnology Research

Effective and targeted delivery of the antitumour drugs towards the specific cancer spot is the major motive of drug delivery. In this direction, suitably functionalised magnetic iron oxide nanoparticles (NPs) have been utilised as a theranostic agent for imaging, hyperthermia and drug delivery applications. Herein, the authors reported the preparation of multifunctional polyethyleneglycol-diamine functionalised mesoporous superparamagnetic iron oxide NPs (SPION) prepared by a facile solvothermal method for biomedical applications. To endow targeting ability towards tumour site, folic acid (FA) is attached to the amine groups which are present on the NPs surface by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride/Nhydroxysuccinimide chemistry. FA attached SPION shows good colloidal stability and possesses high drug-loading efficiency of ∼ 96% owing to its mesoporous nature and the electrostatic attachment of daunosamine (NH3 +) group of doxorubicin (DOX) towards the negative surface charge of carboxyl and hydroxyl group. The NPs possess superior magnetic properties in result endowed with high hyperthermic ability under alternating magnetic field reaching the hyperthermic temperature of 43°C within 223 s at NP's concentration of 1 mg/ml. The functionalised NPs possess non-appreciable toxicity in breast cancer cells (MCF-7) which is triggered under DOX-loaded SPION. © 2020 Institution of Engineering and Technology. All rights reserved.

World University root node

Vellore Campus

Fulltext

IET Nanobiotechnology

Folate encapsulation in PEG-diamine grafted mesoporous Fe2O3nanoparticles for hyperthermia and in vitro assessment

In this paper, luminescence properties of orthovanadates, Y1− x − yGdxVO4:ySm3+ (where x = 0.05–0.50, y = 0.01–0.05), and the energy transfer mechanism from VO4 3− to Sm3+ via Gd3+ ions were investigated in detail. X-ray diffraction (XRD) analysis confirmed the crystalline phase for synthesized nanophosphor in a tetragonal structure with I41/amd space group. The average crystallite size estimated from XRD was ∼28 nm. Field-emission scanning electron microscopy coupled with energy dispersive X-ray analysis revealed oval shaped morphology and composition of the nanophosphor, respectively. From high-resolution transmission electron microscopy observations, the particle sizes were found to be in the range 10–80 nm. The photoluminescence studies of Y0.77Gd0.20VO4:0.03Sm3+ nanophosphor under 311 nm excitation exhibits dominant emission peak at 598 nm corresponding to 4G5/2 → 6H7/2 transition. The energy transfer occurs from VO4 3− to Sm3+ via Gd3+ ions was confirmed by applying Dexter and Reisfeld's theory and Inokuti-Hirayama model. Moreover, the energy transfer efficiencies and probabilities were calculated from the decay curves. Furthermore, Commission Internationale de l'Eclairage (CIE) color coordinate (0.59, 0.37) has been observed to be in the orange-red (598 nm) region for Y0.77Gd0.20VO4:0.03Sm3+ nanophosphor. These results perfectly established the suitability of these nanophosphors in improving the efficiency of silicon solar cells, light emitting diodes, semiconductor photophysics, and nanodevices. © 2017 King Saud University

Arabian Journal of Chemistry

Luminescence properties of yttrium gadolinium orthovanadate nanophosphors and efficient energy transfer from VO4 3− to Sm3+ via Gd3+ ions

Originating from Wuhan, China, in late 2019, and with a gradual spread in the last few months, COVID-19 has become a pandemic crossing 9 million confirmed positive cases and 450 thousand deaths. India is not only an overpopulated country but has a high population density as well, and at present, a high-risk nation where COVID-19 infection can go out of control. In this paper, we employ a compartmental epidemic model SIPHERD for COVID-19 and predict the total number of confirmed, active and death cases, and daily new cases. We analyze the impact of lockdown and the number of tests conducted per day on the prediction and bring out the scenarios in which the infection can be controlled faster. Our findings indicate that increasing the tests per day at a rapid pace (10k per day increase), stringent measures on social-distancing for the coming months and strict lockdown in the month of July all have a significant impact on the disease spread. © 2020 Elsevier Ltd

Department of Communication Engineering

School of Electronics Engineering

Chaos, Solitons and Fractals

An epidemic model SIPHERD and its application for prediction of the spread of COVID-19 infection in India

Fabrication, physical modeling and dynamic response of p -type Al-doped SnOx active channel thin film transistors (TFTs) are presented for the potential application of ultra-high definition (UHD) displays. After deposition of Al-doped SnOx active layer using reactive co-sputtering, the channel was treated with plasma fluorination which improve the device performance of high ION/IOFF ratio of &gt; 106, low subthreshold swing of 100 mV/dec and high field-effect mobility ( μ FE) of 4.8 cm2V-1s-1. To understand the origin of such high performance, physical modeling and numerical simulations were performed using density of state (DOS) model of defects/traps of oxide semiconductor. This model describes the modifications of donor-like tail states and acceptor-like Gaussian defect states due to Al doping on SnOx and fluorine treatment. To evaluate the device performance for UHD large scale displays, the dynamic responses of p -type TFT pixel circuit for various requirements are simulated with physical models. These results suggest that the Al-doped SnOx TFTs are potential candidates for future high-definition displays and many applications in transparent electronics. © 2013 IEEE.

Department of Physics

School of Advanced Sciences

IEEE Journal of the Electron Devices Society

Physical Modeling of p-Type Fluorinated Al-Doped Tin-Oxide Thin Film Transistors

The present study reports the use of one-dimensional carbon wrapped VO 2 (M) nanofiber (VO 2 (M)/C) as a cost-effective counter electrode for dye-sensitized solar cells (DSSCs); where M denotes monoclinic crystal system. Uniform short length nanofiber was synthesised by a sol-gel based simple and versatile electrospinning and post carbonization technique. The investigation of nanostructure and morphological analysis were performed by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), and transmission electron microscope (TEM) with EDAX. The electrochemical response was comprehensively characterized by cyclic voltammetry, electrochemical impedance spectroscopy and Tafel polarization. The electrochemical analysis of the VO 2 (M)/C nanofiber counter electrode exhibits significant electrocatalytic activity towards the reduction of triiodide and low charge transfer resistance at the electrode-electrolyte interface. The DSSCs fabricated with carbon-wrapped VO 2 (M) nanofiber CE showed high power conversion efficiency of 6.53% under standard test condition of simulated 1SUN illumination at AM1.5 G, which was comparable to the 7.39% observed for conventional thermally decomposed Pt CE based DSSC under same test conditions. This result encourages the next step of modification and use of low-cost VO 2 (M) as an alternate counter electrode for DSSCs to achieve a substantial efficiency for future energy demand. © 2019, The Author(s).

VIT Unitversity

Scientific Reports

Pt-free, low-cost and efficient counter electrode with carbon wrapped VO2(M) nanofiber for dye-sensitized solar cells

Numerical analysis of surface plasmon behaviour is performed on graphene surface supported on different dielectric medium and with varying graphene chemical potential. The dielectric medium of graphene is varied from free standing graphene to rigid SiO2 wafer substrate to flexible PMMA polymer for diverse graphene plasmonics applications. The dispersion relation, propagation length and penetration depth of graphene surface plasmons are computed and analysed for the different dielectrics. The results show that graphene plasmonic behaviour in the various dielectrics highly depends on its chemical potential, the excitation input frequencies and produces surface plasmons with high field localization and low losses. This study of plasmonic behaviour on flexible dielectric opens up application of graphene plasmonics in the field of flexible optoelectronics.

Electronics

Chennai Campus

International Journal of Recent Technology and Engineering Regular Issue

Frequency Dependent Graphene Surface Plasmon Properties on Different Dielectrics

Semiconductor photocatalysts are one of the major sought area of research due to their extensive use in the degradation of organic pollutants under UV–visible and solar light. Herein, we are reporting the synthesis of microscopic spindle shaped ZnO photocatalysts with different reducing agents such as sodium hydroxide, hydrazine hydride, sodium borohydride and lithium triethyl borohydride. These spindle shaped ZnO are synthesized by facile soft chemical approach by varying reducing agents with fixed molar ratio at 1:2 zinc precursor to reducing agents. These ZnOs were thoroughly characterised by various sophisticated characterization techniques such as XRD, FTIR, SEM, and HRTEM, Raman and ESR spectroscopies. Microscopic results show that these ZnO show similar fusiform morphologies with the variation in sizes and their distributions, and hence possess different defect related properties. The structural growth mechanism and defect related properties were explained on the basis of different reducing abilities of reducing agents (different reaction pH) and their nucleation with the aid of morphological analysis, and ESR analysis. Furthermore, the photocatalytic activity of these spindle shaped ZnO were evaluated against two cationic dyes (methylene blue dyes, Rhodamine B) under UV light. The photocatalytic results show that these spindle shaped ZnO are very effective for the photo-catalytic degradation of methylene blue and rhodamine B dye under the illumination of UV light. © 2019, Springer Nature Switzerland AG.

SN Applied Sciences

Effect of induced defects on the properties of ZnO nanocrystals: surfactant role and spectroscopic analysis

MnFe2O4/Graphene and ZnFe2O4/Graphene Nanocomposites (MFG &amp; ZFG)were synthesized by solvothermal route and further tested as promising electrocatalyst towards Hydrogen Evolution Reaction (HER). The morphology, structural and electrochemical activity of the nanocomposites were studied by X-ray Diffraction, Scanning electron microscopy, Transmission electron microscopy, Linear Sweep Voltammetry (LSV), Cyclic Voltammetry, Tafel polarization and Electrochemical Impedance Spectroscopy (EIS). MnFe2O4/Graphene and ZnFe2O4/Graphene nanocomposites were found efficient electrocatalysts for hydrogen generation via the hydrogen reduction mechanism. The nanocomposites exhibited good activity in acidic medium with a low over potential (313 mV and 315 mV)and a Tafel slope of 106.4 mVdecade−1 and 114.3 mVdecade−1 respectively. An exchange current density of 60.11 mAcm−2, 47 mAcm−2, TOF being 1.47H2/s and 1.09H2/s was observed for MFG and ZFG. Further, an electrochemical specific surface area of 1.51 mFcm−2, 0.3 mFcm−2 and a less charge transfer resistance value of 8.5Ω and 13.0Ω was calculated for MFG and ZFG electrocatalysts respectively. The kinetic parameters indicated that the reaction was governed by Volmer mechanism. © 2019 Elsevier B.V.

Journal of Alloys and Compounds

Manganese and zinc ferrite based graphene nanocomposites for electrochemical hydrogen evolution reaction

In recent years, considerable attention has been given to the plant-mediated synthesis of nanoparticles because it is an eco-friendly method compared to the synthesis by chemical route. This study aims to optimise the biosynthesis of zinc oxide nanoparticles (ZnO-NPs) mediated by coconut water using response surface methodology (RSM). The effects of the individual variables (concentration of coconut water, temperature and time) and their interactions during the biosynthesis of ZnO-NPs were determined by RSM employing Box-Behnken design. The variables selected were tested by a 17-run experiment and quadratic model was used for the analysis of the results. The accuracy of the model was confirmed by the coefficient of determination (R2) value of 0.9968. The significance of the regression model was found to be high which is validated by the low probability value of P &lt; 0.0001. The ZnO-NPs thus synthesised was evaluated for its antimacrofouling activity against mollusks using in-vitro foot-adherence bioassay. The results demonstrated the potential of biosynthesised ZnO-NPs in inhibiting fouling induced due to the test organisms. © The Institution of Engineering and Technology 2019

Department of Bio-Medical Sciences

School of Bio Sciences and Technology

Process optimisation for green synthesis of ZnO nanoparticles and evaluation of its antimacrofouling activity

The category of transition metal nitrides has been least explored for DSSC. Here, Mo2N was synthesized by a solgel followed by nitridation method and utilized as the counter electrode for DSSC. The structural studies were carried out with XRD, morphology with SEM, TEM, electrochemical studies with Cyclic Voltammetry, EIS and Tafel. Further I-V characteristic was studied using solar simulator Oriel Class AAA under standard test conditions. The Mo2N counter electrodes showed excellent electrochemical activity comparable to that of platinum. DSSC with Mo2N generated an average efficiency of 2.79% and hence can be a promising alternative to Platinum. © 2019 Elsevier Ltd. All rights reserved. Peer-review under responsibility of the scientific committee of the Exploring Nanostructures for Enhanced Power Conversion Efficiency of Solar Cells Conference.