International Seminar on Materials Science and Applications-2016 (ISMSA-2016)

In this work, an analysis has been done in order to describe the structural, electronic, nature and reactivity properties of the Non-steroidal anti-inflammatory drug Aceclofenac in detail. A great agreement is seen between experimentally and theoretically obtained structures and their parameters. The atomic charges which have been obtained from AIM, Mulliken, Hirshfeld and natural population analysis give better understanding towards the distribution of charges in the molecule. The NBO analysis provides path way to find out the charge transfer within the molecules and the strongest interaction and the details of various contributions of the atoms which involve in the bonding formation. The electrostatic potential predicts the sites of electrophilic and nucleophilic attack in the molecule.
Keywords: Charge, reactivity, electrophilicity index, electrophilic region, electrostatic potential

Manganese doped Multiwalled carbon nanotubes were synthesized through a solvo thermal method. The surface morphology and structural analyses of the MnO2 doped MCNT have performed by Transmission electron microscope (TEM), Field emission scanning electron microscope (FESEM), Atomic force Microscope (AFM), X-ray diffraction (XRD) and Energy dispersive spectroscopy (EDS). Fourier transform infrared (FTIR) spectrometry was used to analyze the chemical bonding and type of functional groups grafted onto the nanotubes. Morphological characterization reveals that three-dimensional hierarchy architecture built with a highly porous layer consisting of interconnected MnO2 uniformly coated on the CNT surface. The XRD and EDS results confirmed that the prepared samples containing MnO2/CNT in pure form without impurities. It also reveals that birnessite-type MnO2 is formed through the solvo thermal synthesis. The phase transition was take place at the annealing temperature of 400 C – 500 C.
Keywords: MWCNT, MnO2, Solvo thermal method, Nanocomposites, chemical bonding

The organic nonlinear optical salt trans – 4' – (dimethylamino) – N – phenyl – 4 – stilbazolium hexafluorophosphate (DAPSH) was synthesized and single crystals of DAPSH were grown by slow evaporation method using acetonitrile as solvent. The structure of the crystal was studied using single crystal X - ray diffraction. FTIR analysis were carried out to confirm the functional groups present in the crystal. From UV – vis –NIR studies, the crystal was found to be transparent in the region 400 -1100 nm. Dielectric constant and dielectric loss of DAPSH were measured in the frequency range from 50 Hz – 5 MHz at different temperatures. The surface features of the DAPSH crystal were analyzed by scanning electron microscope.
Keywords: DAPSH, THz, SEM.

Organic nonlinear optical crystal N, N-dimethylamino-N'- methylstilbazolium p-chlorobenzenesulfonate (DASC) has been successfully grown from mixed solvent of methanol: acetonitrile (1:1) solution by adopting slow solvent evaporation technique. Single crystal and powder X-ray diffraction analysis was carried out and it shows that DASC crystal belongs to monoclinic structure with Cc space group. The optical absorption is studied by UV-Vis absorption spectra. Second-harmonic generation (SHG) of DASC crystal has been investigated using Kurtz and Perry technique.
Keywords: Organic compound; X-ray diffraction; Stilbazolium derivative; Nonlinear optical materials

Al doped ZnO thin film (AZO) were deposited on cheap glass substrate by successive ion layer adsorption and reaction (SILAR) method at 0.1M concentration of zin nitrate hexahydrate and 1% of aluminium chloride hexahydrate. The structural, morphological and optical characterization on the AZO thin film such as X ray difraction, SEM and UV-visible spectrometer are taken respectively. From XRD study, the AZO thin film is polycrystalline in nature with hexagonal structure and the average crystallite size is 33 nm. The most prominent peaks corresponding to [100], [002] and [101] planes are found. SEM image of the thin film showing smooth and uniform flower grains on to the surface of the film. The transmittance of the film were as high as 80% in the visible range from 400-700 nm and the direct band gap value is 3.0eV. This technique is very simple and low cost to producing AZO thin film.
Key words: Al doped ZnO, SILAR, Structural, morphological and Optical measurements..

In this work, flower-like MnO2 nanostructure was successfully synthesized by reducing potassium permanganate in acidic condition employing microwave-assisted reflux method. The as-prepared samplewas characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray analysis (EDX) and high resolution transmission electron microscopy (HRTEM). Electrochemical measurements were carried out with three electrode configuration by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). The electrochemical results indicate that the prepared material can be used as electrode material for energy storage applications.
Keywords: Manganese dioxide, Microwave-assisted reflux, Nanostructure, Supercapacitor

In this paper, preparation of titania nanotubes (TiO2 NTs)through rapid breakdown anodization (RBA) is described. Bundles of TiO2 NTs were formed as observed in the Scanning Electron Microscope (SEM) at an applied potential of 20 V. Elemental analysis through Electron Diffraction X-ray Analysis (EDAX) confirmed the presence of only Ti and O peaks and revealed the absence of any impurities in the formation process. The anatase phase of TiO2 NTs was established using X-ray Diffraction (XRD). Characteristic peaks of TiO2 were noticed in the Fourier Transform Infra-red Spectroscopy (FT-IR). The TiO2 NTs powder was found to be stable in anatase form till 500 oC using Thermogravimetry and Differential Thermal Analysis (TGDTA). This TiO2 NTs powder sample was then subjected to investigate the photocatalytic activity through the photo-degradation of methylene blue (MB). The percentage of photo-degradation was examined using UV-Visible spectrophotometer (UV-Vis).
Keywords: Titanium dioxide, Nanotubes, Rapid breakdown Anodization, Photocatalysis

Graphene has gained considerable research interest for the potential applications in composites, energy conversion and energy storage devices. Graphene based materials are currently being studied in the field of science and engineering due to their fascinating thermal, mechanical, electronic and electrochemical properties. To realize the practical applications of graphene based materials, it is highly desirable to prepare scalable and high quality graphene via low cost and environment friendly approach. In this work, we report the room temperature preparation of graphene oxide (GO) from graphite powder with slight modification in the improved Hummers' method. The prepared GO was chemically reduced at relatively low temperature. The structural, morphological and chemical properties were investigated by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). From the HRTEM images, thin and transparent graphene sheets with typical wrinkled structure were observed. The material developed by simple and low cost method may find applications in solar cells, supercapacitors and Li-Ion batteries especially, the nanostructures of metal oxides/graphene based composites.
Keywords: Graphene oxide, Improved Hummers method, Reduction.

In the present investigation, we have attempted the incorporation of Plasmon into SnO2 nanoparticles to tailor their electrical, optical and structural properties for prospective application as photoanode in DSCCs. Bare and Cu assisted SnO2 nanoparticles were synthesized via facile sol-gel approach and characterized using X-ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), UV–VIS Diffuse Reflectance Spectroscopy (DRS), and Field dependent dark and photoconductivity studies. Both samples confirmed the tetragonal structure of SnO2. FESEM images of bare and Cu assisted samples evidenced nearly spherical nanoparticles. It was found from UV–VIS Diffuse Reflectance Spectra (DRS) that due to Cu incorporation, the absorbance of SnO2 has extended to the visible portion of the spectrum due to Surface Plasmon Resonance (SPR) phenomena. Field dependent dark and photoconductivity studies revealed that Cu supported SnO2 nanoparticles show ~ 36 folds higher photocurrent than bare one, thereby exhibiting an excellent photo response. On comparison, Cu assisted SnO2 nanostructured photo anode showcased improved performance and could serve as a potential photo anode for photovoltaic applications.
Keywords- SnO2; Plasmon, FESEM; Field dependent dark and photoconductivity; UV-DRS

Tin oxide (SnO2) nanoparticles and Silver (Ag) doped SnO2 nanoparticles synthesized via facile sol-gel route have been investigated in the present study for conditions relevant to their utilization for optical applications. The as-synthesized nanoparticles were evaluated by different characterization tools for structural, morphological and optical descriptions. X-Ray Diffraction (XRD) studies and Field EmissionScanning Electron Microscope (FE-SEM) studies indicate decrement in crystallite and particle size for Ag doped SnO2 nanoparticles than bare SnO2 nanoparticles suggesting an enhancement in surface area for the Ag doped SnO2 nanoparticles.The Ag doped SnO2sample was found to be optically enhanced than that of bare SnO2 nanoparticles as understood from Ultra Violet–Diffuse Reflectance Spectroscopy(UV-DRS) analysis. The findings from the present study assert that the Ag doped SnO2 nanoparticles present feasibility for energy and optical applications.
Keywords: SnO2, Sol-gel, Silver, Optical, Energy.

An aqueous solvothermal method was used to synthesise anatase TiO2 nanococoons using titanium isopropoxide and ammonium hydroxide (25%) as solvent. The X-ray diffraction pattern was used to confirm the highly crystalline nature of the anatase TiO2. High resolution transmission electron microscopy (HRTEM) reveals nanococoons with diameter of about 15nm and length of about 50 nm with few rhombohedral particles. The HRTEM along the length of the rod shows the fringe spacing of 0.35 nm corresponding to (101) planes of anatase TiO2. The UV visible diffuse reflectance spectrum shows a blue shift in the band gap (3.4 eV) . Room temperature PL spectrum shows a sharp luminescence peak in the green region of the visible spectrum.
Keywords: Nanococoons, blue shift, solvothermal method

L-Alanine oxalate [C8H16N2O8], abbreviated as LAO material were grown from aqueous solution by
low temperature solution growth technique. The harvested crystals have been subjected to single crystal XRD to
identify the cell parameters. FTIR spectroscopy reveals the presence of functional groups in the grown crystal.
Microhardness studies were carried out using Vickers pyramidal indentation method at room temperature shows
the crystal belongs to soft material category.

Glycine Lithium Sulphate (GLS) is one of the potential materials for non-linear optical property applications. Single crystals of glycine lithium sulphate (GLS) with very high degree of transparency were grown from aqueous solution by slow evaporation technique. Single crystal X-ray diffraction analysis reveals that the crystal belongs to orthorhombic system with the space group Pna21. The presence of functional groups was identified from FTIR spectrum. The optical absorption study depicts the transparency of the crystal in the entire visible region and the cut off wavelength has been found to be 300 nm. The microhardness studies were also reported for grown crystals.

Spinel cobalt ferrite (CoFe2O4) nanoparticles have awestruck incredible and remarkable combinations of properties, principally its optical properties and magnetic. These properties are catered in CoFe2O4 which make it a fitting candidate in the field of electronics. Nanocrystalline CoFe2O4 powders were expediently synthesized by a primitive co-precipitation technique. The X-ray Diffraction (XRD) pattern shows that all diffraction peaks were indexed as the cubic spinel structure and the particle sizes has been calculated using Scherrer equation. The estimated average grain sizes were about 10.58 nm corresponding to the most prominent plane (311). The Fourier transform infrared (FT-IR) characterization of the synthesized sample confirmed the inverse spinel structure of cobalt ferrite. By analysing the UV- Visible Absorption Spectra, their optical band gaps (Eg) were calculated. Magnetic property of cobalt ferrite nanoparticles were studied using Vibrating Sample Magnetometer (VSM). Obtained rententivity values for the sample synthesized is 8.7338×10-3emu/g. Further the Coercivity value is found out to be 427.03 G.
Keywords: Cobalt Ferrite (CoFe2O4); Nanomaterials; Coprecipitation synthesis; X-ray technique.

The I2-II-IV-VI4 quarternary compound copper zinc tin sulphide (CZTS), due to its manifold merits such as near optimum direct band gap energy of 1.4 to 1.6 eV, large absorption coefficient (>104 cm-1), non toxic and earth abundant constituents, has become an promising material for photovoltaic applications. Investigations on the structural, morphological and optical properties of CZTS nanoparticles synthesized by a simple co-precipitation technique with copper chloride dihydrate, zinc chloride, tin (IV) chloride pentahydrate and thiourea were carried out in the present work using powder x-ray diffraction (XRD), uv-visible spectroscopy (uv-vis), photoluminescence spectroscopy (PL) and scanning electron microscopy (SEM) analysis. The crystalline nature and purity of the sample was confirmed by XRD. All the diffraction peaks were indexed to kesterite CZTS nanoparticles and the average grain size was estimated using the Sherrer formula. SEM observations demonstrate the morphology of the nanoparticles. The Uv-vis and PL measurements divulge the optical properties which confirm that the prepared CZTS nanoparticles will be an fitting entrant for photovoltaic applications and other light emitting applications.

The synthesis and growth of an ionic organic crystal 4-N, N-dimethylamino-4-N'-methylstilbazolium 4-aminotoluene-3-sulfonate (DAAS) are reported. The chemical composition of DAAS crystal was determined using CHN analysis. The single crystal XRD data of DAAS crystal confirms triclinic structure with non-centrosymmetric space group of P1. The proton NMR spectrum was recorded by dissolving the sample in deuterated methanol to confirm the presence of hydrogen. Dielectric measurements in the frequency range of 50 Hz - 5 MHz suggest that the permittivity and the dielectric loss of DAAS decrease with increase in frequency at different temperatures.
Keywords: Ionic organic crystal; Stilbazolium derivative; Single Crystal XRD; CHN analysis; NLO material

Novel organic material P-hydroxy N-Methyl 4-Stilbazoliumchlorobenzoate (HMSCB)was synthesized by metathesization of the P-Hydroxy N-Methyl stilbazolium Iodide (DHSI) salt with sodium p-chloro benzoic acid. Growth of nonlinear optical HMSCB crystal was carried out with the addition of activated carbon into the methanol solutions by adopting the slope nucleation coupled slow evaporation method. HMSCB crystals with size 3×2×2 mm3 were grown within a period of 35 days. Thecrystalsystemandlattice parameterswerefoundfromsinglecrystalX-raydiffractionstudies.The actual composition and various functional groups present in the sample were identified from Fourier transform infrared (FT-IR) spectral studied. The UV-Vis –NIR absorption spectra and microhardness studiesof the sample were used to find the nature of transition occurred in the sample.

Semi Organic Potassium Hydrogen Phthalate single crystal with amino acid L-Phenylalanine as a dopant was grown by slow evaporation technique. The grown crystals were subjected to powder XRD analysis, and the results confirm its structure and lattice parameters. The Fourier Transform confirms the incorporation of L-Phenylalanine in to KHP crystal. The optical transparency of the grown crystal was studied by UV-Visible spectroscopy. Mechanical strength of the grown crystal was estimated by Vickers hardness Test. Both dielectric constant and dielectric loss decreases with the increase in temperature at constant frequency.
Key words: Semi - organic material; X-ray diffraction; Infrared spectroscopy; optical transmittance studies; Dielectric studies;

The pure and Co doped CdS polycrystalline films have been deposited onto glass substrates by Chemical Bath Deposition (CBD) method. X - ray diffraction (XRD) pattern reveals that all the films exhibit hexagonal phase with preferential orientation and the estimated crystallite size decreased from 38nm to 24nm for pure and Co doped CdS films. SEM images show that the deposition covered the substrate well. Energy dispersive X-ray study confirmed the presence of Cd, S and Co in the films. Fluorescence spectra for as prepared films exhibit two distinct strong emission peaks around 518nm and 541nm. The sulphur deficiency is reduced due to the presence of Co dopant. The room-temperature ferromagnetic behavior obtained only for Co doped CdS films. This DMS material is mainly used for spintronics applications.
KEYWORDS: CBD, fluorescence, DMS, ferromagnetic, spintronics.

The effective reduction and regeneration triiodide/iodide (I3-/I-) redox couple are important for an efficient Dye Sensitized Solar Cell (DSSC) that is ruled by the properties of the counter electrode (CE). Among the non-noble metal electro catalysts, transition metal dichalcogenide, molybdenum disulphide has been identified as a low cost and efficient platinum free potential counter electrode material for Dye Sensitized Solar Cells (DSSCs). The present work reports, the morphological effect of MoS2 nanoflakes via convenient hydrothermal method. The physical and chemical properties of the as-synthesized samples were characterized using different analytical tools. From the morphological studies, it is observed that the nano flakes have a layered planar structure with smooth surfaces which benefit the enhancement of electrochemical activity. The UV-diffuse reflectance spectrum confirms the band structure transition due to the quantum confinement effect of MoS2. The photoconductivity studies revealed that there is a linear increase of current in the dark and visible light-illuminated MoS2 nanoflakes with increase in the applied field. Thus, the improved photoconductive and interesting behavior of MoS2 nanoflakes validates it as a promising counter electrode for DSSCs.
Keywords: DSSCs, MoS2, Nanoflakes, Counter electrode, Transition metal dichalcogenide.

Organic stilbazolium family single crystal 4-N, N-diethylamino-4-N-methyl-stilbazolium Iodide (DESI) has been successfully grown from aqueous methanol solution by adopting slow solvent evaporation technique. Single crystal X-ray diffraction analysis was carried out and it shows that DESI crystal belongs to triclinic structure with P-1 space group. The presence of hydrogen in the crystal structure was determined by recording H1 NMR spectrum. The excitation spectrum of the DESI was recorded by fluorescence analysis. The thermal study confirms the stability of the material.
Keywords: Organic compound; X-ray diffraction; Thermal Analysis; Proton NMR

Metal sulphides establish a diverse and essential group of materials. Lead Sulphide exhibit more interest owing to its extensive range of properties, structures and applications. The present work was focused on the hydrothermal materialization of cetyltrimethyl ammonium bromide (CTAB) surfactant mediated PbS nanoparticles. The X-ray diffraction spectrum confirmed the cubic PbS phase formation. The optical property of CTAB capped PbS nanoparticle was examined using UV spectrophotometric analysis. Fourier transform infrared spectrum was studied to reveal the functional group of PbS nanoparticles. High-resolution transmission electron microscopy (HRTEM) images show that the morphology of the CTAB capped lead sulphide sample consists of cubic structure and also confirms the crystalline nature of the particles with distinct lattice fringes. The dielectric analysis provided information on the dielectric constant and the AC conductivity helped us to understand the significance of polarization of the material.
Keywords: Lead Sulphide, CTAB, hydrothermal method, UV-Vis analysis, HRTEM and Dielectric analysis.

Dye Sensitized Solar Cell (DSSC) was fabricated using TiO2-ZrO2 thin film nanocomposite photoelectrode. We report herein the analysis of a nanocomposite TiO2-ZrO2 in thin film form, synthesized through facile sol-gel methods followed by spin coating respectively. The as-synthesized samples were characterized by Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD), Fourier Transform Infrared (FT-IR) spectroscopy, Ultra Violet -Visible Spectroscopy (UV-Vis) and Photoconductivity techniques. FESEM micrographs revealed lamellar and rough pattern of interconnected pores and nanoscale-particle in the thin film nature. XRD results indicated the presence of TiO2 peaks in anatase phase and ZrO2 in amorphous form. FTIR spectra asserted the presence of Zr-O-Ti vibrations. The UV–Vis absorption spectra of as-synthesized sample shows slight shift in the absorption peaks towards near visible region. The field dependent dark and photoconductivity studies revealed the linear increase of dark and photocurrent with increase in applied electric field. Hence the DSSCs based on TiO2-ZrO2 nanocomposite photoelectrode shows enhancement in solar power conversion efficiency (ƞ).
Keywords: Nanocomposite, Thin film, Sol-Gel, Spin Coating, Photoconductivity, DSSCs.

Isatin (1H-indole-2,3-dione) is an endogenous compound that has been identified in humans and possesses a wide range of biological activities, such as anxiogenic and sedative activities. A variety of biological activities are associated with isatin, including central nervous system (CNS) activities (Raj, 2012). The single crystal X-ray diffraction study of the title compound has been made and its structure is compared with the optimized structure obtained with MOPAC2016's PM7 algorithm. The title compound, C10H8BrNO2, containing the isatin moiety crystallized with two independent molecules (A and B) in the triclinic space group P-1. The unit cell parameters are a=9.5293 (3) Å, b= 0.0581 (3) Å, c= 1.2138 (3) Å, =78.921 (1)°, =75.261 (1)°, = 85.151 (1)° with V=982.34 (5) Å3 and Z=4. The structure is solved by direct methods using SHELXS-97 and refined by full matrix least square on F2 to an R- value of 0.03 for 2982 reflections (I>2(I)) using SHELXL-2014. The total energy and dipole moment of the title molecule are computed as -2335.01 eV and 4.642 Debye respectively. The relative conformation about the bond joining the isatin moiety and the ethyl group of the compound is defined by the C1—N1—C9—C10 torsion angle, 78.9 (4)° and 86.7 (5)° in molecules A and B respectively, decreased to 72.41° in the isolated optimized structure. This indicates a greater twist leading to further separation between the isatin moiety and ethyl group and suggests that the crystal packing is influenced by the collective effect of the intermolecular interactions. The structural stability of the crystal is found mainly to be due to C—H···O interactions.

In recent years the synthesis of metal doped nanoparticles has attracted particular attention owing to their structural, morphological, optical and photoconducting properties. In the present work, a simple sol gel method is followed to synthesize Aluminium (Al) doped Zinc Oxide (ZnO) nanoparticles. The as- synthesized nanoparticles were characterized by X-Ray Diffraction (XRD), High Resolution Scanning Electron Microscopy (HRSEM) equipped with Energy Dispersive X-Ray Spectroscopy analysis (EDAX), Ultra Violet-Diffuse Reflectance Spectroscopy (UV-DRS) and Brunauer–Emmett–Teller (BET) Analysis which evidenced the formation of highly crystalline, homogeneous nanoparticles with an average crystallite size of 23.15nm, band gap of 2.57eV and surface area of 7.68m2 /g respectively. Also investigation of the electrical properties of the sample using field dependent dark and photoconductivity measurements presented a significant increase in photoconductivity. Thus the results show that Al doped ZnO would be a promising candidate for photovoltaic applications especially as photoelectrodes in Dye-Sensitized Solar Cells (DSSCs).
Keywords: Band Gap, Doping, Optical Properties, Photoconductivity, Sol-gel

Polymer electrolytes are an important component of many electrochemical devices. In the present study, an attempt has been made to prepare the proton conducting polymer electrolytes based on poly vinyl alcohol doped with amino acid proline and different molar ratios of ammonium thiocyanatethat have been prepared by Solution Casting Technique using distilled water as solvent. The maximum conductivity has been found to be 1.1710-3 S/cm at ambient temperature for 75Mwt% PVA: 25Mwt% Proline: 0.5 molar mass percentage NH4SCN polymer membrane using AC impedance analyzer. The temperature - dependent conductivity of the polymer membrane obeys Arrhenius behavior. The highest ionic conductivity polymer electrolyte has low activation energy 0.08eV among the prepared polymer electrolytes. The dielectric spectra exhibit the low frequency dispersion due to space charge accumulation at the electrode – electrolyte interface.
Keywords: AC Impedance analyzer, Dielectric studies.

In the present work, pure and Zn2+ ions doped ninhydrin single crystals were grown by slow evaporation method. The powder X-ray diffraction analysis was done to calculate the lattice parameters of the pure and doped crystals. The vibrational frequencies of various functional groups in the crystals have been derived from FT-IR analysis. The percentage of transmittance of the crystal was recorded using the UV-Visible Spectrophotometer. The mechanical strength of the crystal was found out using Vickers microhardness test. The second harmonic generation efficiency was employed by powder Kurtz method.
Keywords: Organic crystal, X-Ray diffraction method, FT-IR analysis, Vickers microhardness test, second harmonic generation (SHG)

Pure and Ni–doped Tin Oxide (SnO2) nanoparticles were synthesized by simple co-precipitation method. The structural, morphological and optical properties of these nanoparticles were investigated by using X-ray diffraction, UV-Vis spectroscopy, FTIR and Photo Luminescence Studies. The X-ray diffraction revealed that all samples are pure tetragonal rutile- structure with crystalline space (P42/mnm) and the nickel doping did not change the tetragonal structure of tin oxide. The optical band energies of pure and Ni doped SnO2 nanoparticle were evaluated from UV-Vis-NIR studied and found to be 2.16 eV and 1.75 eV respectively.
Key Words: Tin Oxide, X-ray Diffraction, UV-Absorption, FTIR, PL Studies

Pure and Ni–doped Tin Oxide (SnO2) nanoparticles were synthesized by simple co-precipitation method. The structural, morphological and optical properties of these nanoparticles were investigated by using X-ray diffraction, UV-Vis spectroscopy and SEM Studies. The X-ray diffraction revealed that all samples are pure tetragonal rutile- structure with crystalline space (P42/mnm) and the nickel doping did not change the tetragonal structure of tin oxide. The optical band energies of pure and Ni doped SnO2 nanoparticle were evaluated from UV-Vis-NIR studied and found to be 2.16 eV and 1.75 eV respectively. The surface morphology of the pure and Ni doped SnO2 nanoparticles studied by SEM.
Key Words: Tin Oxide, X-ray Diffraction, UV-Absorption, SEM Studies

PThe present work elaborates the dielectric and cyclic voltammetric behaviour for pure and lanthanum doped γ-manganese dioxide nanoparticles. The structural characterizations clearly reveal the Nsutite phase of the material with their orthorhombic nature and good crystallinity. The doped samples also display the same nature with successful incorporation of lanthanum ions. The dielectric constant is found to be a frequency dependent parameter. The dielectric loss depends on a.c. resistivity and the a.c conductivity depends on the interfacial polarisation and electrical conduction. The cyclic voltammetric behaviour shows the material to display a quasi-reversible redox process and the specific capacitance of the doped samples are higher than the pure ones.
Key Words: manganese dioxide, cyclic voltammetry, quasi-reversible redox process

An important area of research in nanotechnology is the biosynthesis of silver nanoparticles which are found to have wide applications. Micro-organisms and plant extracts have received attention for the biosynthesis of nanoparticles.A novel approach for the green synthesis of silver nanoparticles (AgNPs) from aqueous solution of AgNO3 using fungus culture is reported in this work. Several fungi were isolated from soil among which Aspergillusniger was found to be most promising organism which were able to convert AgNO3 solution to silver nanoparticles extracellularly. The synthesis was observed within 24h, and AgNPs showed characteristic absorbance around 410 nm. Spherical nanoparticles of size 50-100 nm were observed in transmission electron microscopy. The AgNPs showed highly potent antimicrobial activity against Gram-positive, Gram-negative bacteria.It may be concluded from this experiment that silver nanoparticles obtained from fungus are very significant and indicate that the synthesized silver nanoparticles may have an important advantage over conventional antibiotics.
Key Words: Aspergillusniger, Nanoparticles, Antibacterial activity, SEM.