Experimental Techniques For The Synthesis And Characterization Of Nanomaterials

Semiconductor Nano crystals or quantum dots are materials that are typically 2-20 nm in diameter, consisting of approximately twelve to fourteen thousand atoms. The effect of quantum confinement results, in the electrons and holes in the Nano crystal to exhibit quantized energy states; thus enabling them to exhibit novel physical properties that are not found in their bulk counterparts. Research in semiconductor quantum dots started with the realization that the optical and electronic properties of these particles were strongly dependent on particle size, due to quantum confinement of the charge carriers in small spaces.

Goal: Synthesize Cadmium Selenide (CdSe) Quantum Dot Crystals using Cadmium Oxide (CdO) and Selenium (Se) dissolved in Triphenylphosphine solution. The product created will be a colloidal solution, bound to the exterior of the crystal lattice and it remains soluble in the octadecene (Boatman & Nordell). Along with this the product will most likely vary in color as well due to the changes in wavelength, energy and transitions, that all correspond to a smaller crystal. The variations in particle size will prove to be an important feature in the experiment, so the goal is to use diverse size particles. The crystals are created in a solution in which they cannot be filtered out since they do not settle.

Nanotechnology is a term of two words: the first word is “Nano” and derives from the Greek word “Nanos” and it means “Dwarf” or something very small. The second word is “Technology” and it means applied application of knowledge in a certain field. So nanotechnology is the technology of very small substances, and it specializes in treating the substance on the Nano measure to produce new, useful, and unique resultants in its properties [22-23].The Nano is a unique measuring unit and from the physical and mathematical point of view, the Nano equals one part of a billion of the measured unit. The nanometer (nm) equals a part of a billion part of a meter. Thus, it is 10-9 of a meter. The Nano is used as a measuring unit for very minute particles [24-26].

Working with nanoparticles is critical due to its nanoscale; they should be handled carefully considering safety

Research Theme: Building on the building blocks of life: Nanoscale materials for investigating biologically inspired and environmentally important systems.

XRD analysis was performed using a PanAlytical X-ray diffractometer with a Cu anode, generating Kα radiation (=1.54046 Å) and operating at 40 kV and 30 mA. Raman spectra were recorded at room temperature with a Bruker Optik GmbH Raman microscope-spectrometer Senterra using a 100x MPLN Olympus objective. The wavelength of the excitation laser was 448 nm. Surface morphology was analyzed by SEM on a Raith PIONEER System and the particle size distribution histogram was determined using particle detection software (SPIP, Image Metrology). A Nanosurf easyScan 2 AFM (Nanosurf, Liestal, Switzerland) in contact mode was employed to obtain topographical images and the Gwyddion software [34] was used for image processing and root mean square roughness (Rrms) calculation. The electrical properties such as resistivity and carrier concentration were determined from Hall Effect measurements at room temperature using an Ecopia HMS-300 system based on the van-der-Pauw method. The optical transmittance spectra were recorded at room temperature by a Safas UVmc2 UV–Vis spectrophotometer and the optical bandgap energy data was then derived from the transmission spectra. The optical waveguiding characterizations were carried with a Metricon Model 2010/M Prism Coupler System equipped with a polarized He-Ne laser beam operating at a 632.8 nm wavelength. A Veeco Dektak 150 Surface Profiler was used for film thickness investigation. The thickness of the AZO films prepared at 6, 12, 18 and 24 coatings was measured to be 232, 425, 617 and 798 ± 1 nm,

Nanotechnology is a novel technology what generally deals with structures and systems with a size less than 100nm. [1] Due to its unique tiny size, the properties are quite different from bulk properties include physical properties, chemistry properties, biological properties. For example, gold in bulk form is inert, but in nano scale, it tends to be very active. Moreover, different sizes, structures, and surface areas of gold nanoparticles make it exhibit different colors.

Nanotechnology, the manipulation of matter on the molecular scale, can be applied to numerous scientific fields, such as medicine, surface chemistry, micro fabrication, and organic chemistry (Destito, Schneemann & Manchester, 2009). In general, these small-sized particles are used to improve the functioning of commercial products and, in the subsection of nanomedicine, are used for therapeutics, tumor targeting, and vaccines (Crisci, Bárcena & Montoya, 2012). For example, the use of molecular nanotechnology improves vehicle fuel cells and catalytic converters, helps filter wastewater, and strengthens commercial products, such as bowling balls and glue. (Doll et. al., 2012). Harisinghani, through multiple experiments, also discovered that nanoparticles such as iron oxide can be used to image lymph nodes in patients with prostate cancer (Destito et. al., 2009). However, even with their vast range of applications, nanotechnology continues to raise issues on its toxicity and negative impact on the environment (Destito et. al., 2009).

Nanotechnology is the gateway to near limitless possibilities for the human race. It opens the window to a new realm we previously have never experienced-- Nanotechnology is a branch of engineering that deals with the manipulation of atoms at the molecular level. The Institute of Nanotechnology in the U.K. expresses it as "science and technology where dimensions and tolerances in the range of 0.1 nanometer (nm) to 100 nm play a critical role”. Once automated, the nanoparticles will infiltrate every aspect of our lives- from medical, engineering, biomaterials energy production, to name a few. Practically everything we use today could be replaced by nanomaterial in some way, and it even has the capability to create new materials.

The understanding that by adding designed shape or interaction anisotropy to nanoparticles will further increase possible packing schemes to the motifs in their self-assembly process. Therefore, the understanding of how individual anisotropy scale up to build complex structures are of desperate desire for designing creative particles to be transformed into materials with desired properties.

Nanotechnology and Applied Nanoscience allow creating innovative nanostructure materials and also technological transformations that excel to develop new materials in every industry i.e. Pharmacy, Chemical, Mechanical, Bio-Medical Science and others. It builds a bridge between the conventional and future technology by teaching lessons to keep environment safe, healthy and in favor of mankind by making contribution to improve of quality of life. Nanoscience open doors for advance researches those are able to change properties of materials by its size and behavior, following all disciplines of engineering while keeping

Today many common commercial products contain some sort of engineered nanoparticles. “Examples include cosmetics, sunscreens, clothes, solar cells, sporting good[s], paints, and electronics” (Kosal 8). Although major developments have only occurred in the last decade, the US military began conducting nanotechnology research in the early 1980s. It was not until the mid-1990s, after the Department of Defense (DoD) identified nanotechnology as one of the six ‘Strategic Research Areas’ of Interest, that major investments in the research and development in nanotechnology began. Nanotechnology research seeks to advance both offensive and defensive military objectives (Lele 234). In January of 2000, President Bill Clinton “unveiled the National Nanotechnology Initiative (NNI) where he called for an initiative with funding levels around 500 million dollars” (Tate 23). “All branches of the U.S. military currently conduct nanotechnology research, including the Defense Advanced Research Projects Agency (DARPA), Office of Naval Research (ONR), Army Research Office (ARO), and Air Force Office of Scientific Research (AFOSR)” (Tate 20). By the conclusion of this paper, the reader will have a basic understanding of nanotechnology and its applicability in military affairs. Additionally, the reader will understand the hazards of nanotechnology in order to determine if the military should continue to focus on nanotechnology.

In producing of CNTs by using CVD method , catalyst helps to CNTs to grow from at surfaces. The growth of the nanotubes can be controlled by van der Waals forces and applied electric

“Nanocrystalline particles represent a state of matter in the transition region between bulk solid and single molecule. As a consequence, their physical and chemical properties gradually change from solid state to molecular behaviour with decreasing particle size.

Akash Mondal B.Tech Student, Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, India