Nanotechnology

Synthesize of optically and high luminescence of ZnO quantum dots in this work. XRD pattern show pure ZnO QDs and are genuinely polycrystalline with a hexagonal wurtzite structure. A typical TEM image of the material showed that particles are spherical in shape and their average size is (4) nm. No quantum dots with a diameter less than 2 nm or larger than 6.5 nm are found. PL spectrum of ZnO QDs is composed of an ultraviolet (UV) emission centered at about 360 nm and a broad green emission centered at about 475 nm.

Today’s pulp and paper industry is rapidly becoming a globalized industry which belongs to the Red category that is positioning itself to deliver low-cost, high-value, fiber-based products to consumers. Employing advanced chemical- and mechanical-based technologies. pulp, paper, and tissue manufacturers have sought to provide high-quality consumer. To overcome the challenges, new synthetic nonrenewable materials have been developed that have now begun to challenge the traditional dominance paper products has had in many applications. This paper will review emerging developments of these technologies and how these new research avenues will change paper from a pass. This presentation deals the vital role of Nano technology in pulp and paper manufacturing sector.

The Au and thiol substituted 2,5-divinylthiophene molecule has been studied for the zero field and various levels of applied external electric fields (EFs) using quantum chemical calculations coupled with AIM theory. The variation in geometrical parameters due to the various external EFs and the corresponding transport properties of the molecule has been analyzed. The variation in MPA and NPA charges, the reduction of HOMO-LUMO gap (from 2.34 to 1.08 eV) and the increase of electric dipole moment (from 0.98 to 13.21 D) with the increase of external EFs (from zero to 0.26 VÅ-1) of the molecule reveals that using thiol as linker and Au as electrodes, 2,5-divinylthiophene molecule can be act as an efficient molecular nanowire.

Porous Silicon (PS) layers were prepared by electrochemical etching in a single-tank cell on the surface of single-crystalline p-type (100) silicon wafers, using hydrofluoric acid (HF) and ethanol (C2H5OH) in the volume ratio of 1:2. The surface and cross-section morphologies of the PS were observed from images obtained using Scanning Electron Microscope (SEM). Likewise, the porosity of the PS sample was determined using the parameters obtained from SEM images by geometrical method. SEM images indicated that, the pores were surrounded by a thick columnar network of silicon walls. This porous silicon layer can be considered as a sponge like structure. The X-ray diffraction (XRD) pattern showed the growth of PS layer on silicon wafer and the grain size of the PS layer was found to be around 60.2 nm. The effective refractive index of porous silicon was calculated using Effective Medium Approximation (EMA) analysis. The optical properties of PS were investigated using Fourier Transform Infrared (FTIR) spectroscopy and Photoluminescence (PL). The surface chemical bonds of the PS were observed by FTIR and the band gap of the PS sample was obtained from PL spectra. The efficiency of ethanol gas sensing properties of PS was investigated at room temperature. The sensor was found to operate with maximum efficiency at a concentration of 100 ppm hence, this PS material can be used as an effective sensor element to detect ethanol vapour.

Smooth and adhesive nanocrystalline diamond (NCD) and microcrystalline diamond (MCD) coatings have been achieved on a chemically etched cemented tungsten carbide (WC-6%Co) substrates, using hot filament chemical vapor deposition (HFCVD) technique. Structural and micro-structural characteristics of these coatings were compared using X-ray diffraction (XRD), Raman spectroscopy and Scanning electron microscopy (SEM) techniques. The parameters affecting the integrity of these coating-substrate systems were studied and mathematical analysis was carried out for calculating the force of de-lamination and load bearing capacity.

Precious metals doped anatase titanium dioxide nanoparticles are used in various applications including environmental photocatalysis and solar cells. In this work we present the synthesis of Au- doped and Pt-doped TiO2 nanoparticles employing sol-gel methodology. The doping procedures based either on UV photodeposition (UV-PD). The morphology, composition, particle size and specific surface area of these synthesized nanoparticles have been characterized using several instrumental techniques namely, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDXS), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM) and Brunauer–Emmett–Teller (BET) theory. Au impregnated (2%) nano anatase TiO2 powder was examined in photo decolourization of Orange G as dye environmental pollutant under visible light illumination and optimum operational conditions.

Green synthesis of Zinc Oxide nanoflowers by plant extract is currently under utilization. This research account on the exploit of aqueous leaf extract of Azadirachta indica in the biosynthesis of bioactive zinc oxide nanoflowers with aqueous solutions of zinc acetate and sodium hydroxide at ambient temperature. The aqueous extract of Azadirachta Indica can be used as a template to control particle size and stabilize ZnO nanoparticles. The ZnO nanoflowers prepared by the green synthesis exhibited a hexagonal wurtzite structure with a crystalline size of 51 nm and particle size of 100 nm. To make the process environmentally viable the reaction was carried out under solvent free conditions. Formation of zinc oxide nanoflowers was confirmed by Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction patterns and scanning electron microscopy (SEM) with Energy dispersive X-ray (EDX) patterns. The results confirmed that aqueous leaf extract of Azadirachta indica is a suitable green template to prepare heterogeneous ZnO nanoflowers. Green methods are be good competent for the chemical procedures, which are environment friendly and convenient.

Gold nanoparticles have been synthesized and they have been made to self assemble on indium tin oxide (ITO) coated with 3-mercaptopropyltrimethoxysilane. An aqueous solution of gold chloride was added to tetraoctyl ammonium bromide dissolved in toluene. The mixture was stirred well. Then an aqueous solution of sodiumborohydride was added and the mixture was stirred for 4 hours at room temperature. The organic phase was washed with water in a separating funnel. The solvent was removed by evaporating the solution in vacuum to get a black solid. The black solid was suspended in ethanol and kept under refrigeration overnight. The residue was filtered and washed thoroughly with ethanol. The residue was dried. The gold nanoparticles produced were characterized by Transmission Electron Microscope (TEM). A clean indium titanium oxide electrode was prepared. It was immersed in an aqueous solution containing potassium ferro cyanide and sodium chloride solution in a three electrode cell assembly. Saturated calomel electrode was used as reference electrode. A platinum foil was used as counter electrode. Cyclic voltammogram was recorded in the potential range of -0.1v to 0.5v at a sweep rate of 50mV/s. The experiment was repeated with the ITO electrode coated with 3-mercaptopropytrimethoxysilane. It was seen from the cyclic voltammogram that the redox peaks were absent and there was decrease in the current. This suggests the formation of MPTMS monolayer which acts as a barrier. Since the redox probe has to diffuse through the monolayer, the redox current decreased compared to the bare ITO. When ITO electrode modified with MPTMS was immersed in gold nanoparticles self assembled on the monolayer of MPTMS. The gold nanoparticles were attached to the –SH groups of MPMS. When CV was run with this electrode, there was increase in redox current suggesting that the GNPs have assembled on ITO electrode modified with MPTMS. These electrodes may find application in Biosensors.

In this work we have demonstrated an experimental study and theoretical analysis of the effect of power intensity of illumination on the SnO2/n-Si Hetero-junction devices that irradiated with 150 min. (Cs 137) Gamma ray. The (J-V) characteristic was plotted as function of power intensity of illumination (1.95, 2.88, 3.78, 5.9, and 9.5) mw/cm2. This was shown increase in efficiency of this device until reach maximum efficiency at 9.5 mw/cm2 which represent optimal case. Theoretical analysis of this processes achieve by using “Table Curve 2D version 5.01” program leading to estimate theoretical modeling equation Y= a + b x +c ex We calculate these parameters (a, b, and c) as function of power intensity and testing the equation for power intensity (4 and 8 mw/cm2). Theoretical (J- V) curves are plotted with experimental data, there is a good agreement between them and the behavior of these two curves contain linear term and exponential term.

In the present work, Y2O3:Eu3+ nanoparticles like-spheres have been synthesized via simple method. Synthesis conditions such as calcination temperature and the additive 2,3-dihyrosybutanedioic acid are played a role for synthesizing Y2O3:Eu3+ nanoparticles with superior optical properties. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies have been carried out to understand surface morphological features and the particle size. The as-obtained nanoparticles have average crystallite size ranging between 25 to 45 nm. Crystal structure of the nanoparticles has been investigated by X-ray diffraction (XRD) technique. The incorporation of Eu3+ activator in these nanoparticles has been checked by luminescence characteristics, establishing that the main emission peak located at 613 nm corresponds to the hypersensitive forced electric dipole transition between 5D0 and 7F2 level of Eu3+ ions.