V S I H S AK A HAPATNAM

Transcription

1 NANO MATERIALS K.SRIYOGI Assistant Professor Department of Industrial Production Engineering GITAM Institute Of Technology VISHAKHAPATNAM Nano technology-introduction: The emerging fields of nanoscience and nanoengineering are leading to unprecedented understanding and control over the fundamental building blocks of all physical matter. This is likely to change the way almost everything from vaccines to computers to automobile tires to objects not yet imagined is designed and made. K.SRIYOGI 2 1

2 Some notes on scale 1A0=10 power -10m 1 nm=10power-9m atomic/crystallographic 1 µm=10power-6m 1mm=10power-3m 1cm=10power-2m micro structure macro structure K.SRIYOGI 3 The word Nano means dwarf in Greek language. Use it as a prefix for any unit like a second or a meter and it means a billionth of that unit. A nanosecond is one billionth of a second. And a nanometer is one billionth of a meter about the length of a few atoms lined up shoulder to shoulder. A world of things is built up from the tiny scale of nanometers K.SRIYOGI 4 2

3 The human bodies are a few nanometers thick. Enzymes typically are constructions of thousands of atoms in precise molecular structures that span some tens of nanometers. The individual components of an Intel Pentium III microprocessor span about 200 nanometers. This is the reason that computing is so powerful and easy these days K.SRIYOGI 5 (a)less than a nanometre- individual atoms are up to a few angstroms, or upto a few tenths of a nanometer in diameter; (b) Nanometer- Ten shoulder-to-shoulder hydrogen atoms (blue balls) span 1 nm. DNA molecules are about 2.5 nm wide; (c) Thousands of nanometers- Biological cells, like these red blood cells, have diameters in the range of thousands of nm; (d) a million nanometers- A pinhead sized patch of this thumb (black point) is a million nanometers across; (e) Billions of nanometers-a two meter tall person is two billion nanometers tall. K.SRIYOGI 6 3

4 Mile Stones In The Evolution Of Nanotechnology 3.5 Mrd.years: First cells with nano machines. 400 B.C: Demokrit: Reasoning about atoms and matter. 1905: Albert Einstein: Calculated molecular diameter. 1931: Max knoll&ernst Ruska: Electron microscope 1959: Richard Feynman: There is plenty of room at the bottom. 1968: Alfred Y.Cho & JohnArthur (Bell Labs): MBE (atomic layer growth). 1974: Norio Taniguchi: Nanotechnology for fabrication methods below 1µm. K.SRIYOGI 7 Contd., 1981: Gerd Binnig& Heinrich Rohrer: Noble prize for inventing Scanning Tunneling Microscope. 1985: Robert F.Carl, Harald W.Kroto: Richard smalley: Bucky balls. 1986: K.Eric Drexler: writing with a STM tool. 1991: Sumio Ligima: Carbon Nanotubes. 1993: Warren robinett, R.Stanley Williams: Combination of SEM and VR (virtual reality system). 1998: Cees Dekkar et all: Carbon nanotube transistor. 1999: James M.Tour& Mark.A.Read: Single molecule switch. K.SRIYOGI 8 4

5 2000: Eigler et all: Construction of quantum mirrors. 2001: Florian Bambers: Soldering of nanotube with e-beam. 2004: Intel launches the Pentium iv PRESCOFT processor based on 90nm technology. K.SRIYOGI 9 Carbon Nano Tube Transistors K.SRIYOGI 10 5

6 This STM image shows the direct observation of standing-wave patterns in the local density of states of the Cu(111) surface. These spatial oscillations are quantum-mechanical mechanical interference patterns caused by scattering of the two- dimensional electron gas off the Fe ad atoms and point defects. K.SRIYOGI 11 Single Molecule Switch K.SRIYOGI 12 6

7 Construction of quantum mirrors K.SRIYOGI 13 Soldering of nano tube with e-beam K.SRIYOGI 14 7

8 Definition: Nano technology relates to the ability to build assembly functional of devices nano scale technological applications. based on objects the for controlled specific Difference between Nano science and Nano technology: Study on fundamental relationships between physical properties and phenomena and material dimensions in the nanometer scale referred to as Nano science. But Nano technology is the application of these nano structures and principles behind them to make nano scale devices and to produce new materials. K.SRIYOGI 15 NANO MATERIALS History of Nanomaterials: The history of nanomaterials began immediately after the big bang when Nanostructures were formed in the early meteorites. Nature later evolved many other Nanostructures like seashells, skeletons etc. Nano scaled smoke particles were formed during the use of fire by early humans. K.SRIYOGI 16 8

9 K.SRIYOGI 17 The scientific story of nanomaterials however began much later. One of the first scientific report is the colloidal gold particles synthesised by Michael Faraday as early as Nanosized amorphous silica particles have found large-scale applications in many every-day consumer products, ranging from non-diary coffee creamer to automobile tires, optical fibers and catalyst supports. In the 1960s and 1970s metallic nano powders for magnetic recording tapes were developed K.SRIYOGI 18 9

10 Nanoscale materials can be defined as those whose characteristic length scale lies within the nanometric range, i.e in the range between one and several hundreds of nanometers( preferably between 0-100nm) nm). According to Siegel, Nano structured materials are classified as Zero dimensional, one dimensional, two dimensional, three dimensional nanostructures. K.SRIYOGI 19 Classification of nanomaterials following Siegel Nano particles Nano wires or Nano rods Thin films Nano composites wires or Nano rods K.SRIYOGI 20 10

11 Some present and future applications of Nanomaterials In electronics & optoelectronics: nano phosphors for affordable high-definition television and flat panel displays. Electroluminescent nano crystalline silicon, opening the way for optoelectronic chips and possibly new type of color displays. Efficient light-emitting diodes based on quantum dots with a voltage-controlled, tunable output color. Powder or plastic layers using nano particles as an active scattering medium. Optical switches and fibers based on nonlinear behavior. Transparent conducting layers. Three-dimensional optical memories. K.SRIYOGI 21 Electronics Materials for the next-generation computer chips. Single-electronelectron tunneling transistors using nano particles as quantum dots. Efficient electrical contacts semiconductor devices. Electrically conducting nano ceramics. Capacitive materials for, random access memories (DRAM). for for, e.g., dynamic K.SRIYOGI 22 11

12 Magnetic Applications Magnetic memories based on materials with a high coercivity. Magneto restrictive materials, important for shielding components and devices. Soft magnetic alloys resistors and varistors resistors). such as Finemet (voltage-dependent High-temperature superconductors nano particles for flux pinning. using K.SRIYOGI 23 In optics Graded refractive index (GRIN) optics: special plastic lenses. Anti-fogging coating for spectacles and car windows. Inexpensive colored glasses and optical filters. In energy storage: Novel solar cells, such as the Gratzel cell based on TiO2 materials. window layers in classical solar cells utilizing the increased band gap due. high energy density (rechargeable) batteries. Smart windows based on the photo chrome effect or electrical magnetic orientation effects. better thermal or electrical insulation materials, again using the higher gap. nano crystalline hydrogen storage materials. Magnetic refrigerators from K.SRIYOGI super paramagnetic materials

13 In Gas sensing devices: Gas sensors for Nox, Sox, CO, CO2, CH4 and aromatic hydrocarbons. UV sensors and robust optical sensors based on nano structured silicon carbide (SiC). Smoke detectors. Ice detectors. Ice detectors on aircraft wings. Protection coatings: Cost-effective corrosion protection materials. Elimination of pollutants in catalytic converters utilising the large surface area of nanomaterials. Scratch-resistanceresistance top-coat using hybrid nano composite materials K.SRIYOGI 25 Medical applications: longer-lasting lasting medical implants of biocompatible nano structured ceramic and carbides. bio-compatible coating for medical applications. magnetic nano particles for hyperthermia. controlled drug release and drug delivery. Catalysis: Photo catalyst air and water purifiers. better activity, selectivity and lifetime in chemical transformations and fuel cells. precursors for a new type of catalyst (Cortex- catalysts). Stereo selective catalysis using chiral modifiers on K.SRIYOGI 26 the surface of metal nano particles. 13

14 THANK YOU K.SRIYOGI 27 14