Presentation on theme: "Nanomaterials and Synthesis"— Presentation transcript:
1Nanomaterials and Synthesis Chapter 1IntroductiontoNanomaterials and Synthesis
2A. Nanomaterials and Nanotechnology Nanomaterial is a key element of Nanotechnology.Nanotechnology is based on nanomaterials.Nanotechnology does not exist without nanomaterials.
3B. Nanotechnology A technology that deals with small structrues or small-sized materials (with a typical dimension spanning from subnanometer to several hundred nanometers.)F1.123- A nanometer (nm) is one billionth of a meter, or 10-9m nm ≒10 hydrogen or 5 silicon atoms aligned in a line.A technology of designing, fabrication and applications of nanostructures and nanomaterials.Fundamental understanding of physical properties and phenomena of nanomaterials and nanostructures.Study on fundamental relationships between physical properties and phenomena and material dimensions in the nanometer scale.
4C. Nanomaterials Materials with at least one dimension falling in nanometer scale or with nano-sale structures.Types of nano materialsF3.14F3.19- Zero-dimensional nanomaterials: nanoparticles or nano powder- One-dimensional nanomaterials: nanofibers, nano wires, nonobelts, nanotubes and nanorods.F4.14F4.7F4.23F4.29- Two dimensional nanomaterials: Thin films, nanoflakes, nano platelets nanosheets and nano coatings.- Three-dimensional nanomaterials:Monolithic, bulk made of nanoscale building blocksor consisting of nanoscale structures.F.1F.8F.3
5Properties of Nanomaterials Materials in the micrometer scale mostly exhibit physical properties the same as that of bulk form; materials in the nanometer scale may exhibit properties distinctively different from that of bulk:• a lower melting point (the difference can be as large as 1000℃);• reduced lattice constants;• band gap broading;(e.g., semiconductors become indulators;)• exhibit catalytic properties(e.g., nano Au particles).9F.8-13F.8-15F.8-22F.8-24F.8-23#12#36
6D. Nanomaterial and Synthesis In order to explore novel physical properties and phenomena and realize potential applications of nanostructures and nanomaterials, the ability to fabricate and process (synthesis and processing) nanomaterials and nanostructures is the first corner stone in nanotechnology.
7E. Some applications of Nanomaterials Zero-dimensional nano materials: Nanoparticles or nano powderOne-dimensional nano materials: Nanofibers, Nano wires, and Nanorods.Two-dimensional nano materials: Thin films, nano flakes, nano platelets nanosheets and nano coatings.Three-dimensional nano materials: Monolithic, bulk made of nanoscale building blocks or consisting of nanoscale structures.147148ABCFig1D10222F.8BNgraphene#40DSC11#13IPervoskite
9Zero-dimensional nano materials (classification of powders according to size) Molecularclusterpowder (particles)0.001μm0.01μm0.1μm1μm1nm10nm100nm1000nmnano powder (particles)submicron powder (particles)microsizedparticlesd < 100nm :nano powder (particles)ultra fine powder (particles)d < 1μm:submicron powder (particles)fine powder (particles)
10Dye-Sensitized Solar Cells mechanism：4. Cathode:1.Absorption2. Electron injection3. RegenerationOur research goals：to synthesize various nanopowder and nanostructured materials (TiO2, ZnO,CeO2…) with different morphologies for the fabrication of semiconductor electrode for DSSCs.Requirement:semiconductor thin film.high specific surface areaenergy levels matching the dye moleculesand the electrolyte(LAMA, NCKU)
25F.1Characterization of BN nanosheets. (a) SEM image of laterally large BN nanosheets. The inset is a BN product of around 100 mg in weight obtained during a single experimental run. (b) A magnified image of an ultra-thin BN nanosheet. (c) TEM image of plentiful BN nanosheets which were dispersed in ethanol. The inset is a selected magnified image showing a detailed folded corrugation landscape. (d) HRTEM image of a six-layered BN nanosheet. The inset image is a zoomed-in picture indicating a perfect honeycomb-like BN crystal lattice. The inset profile is the corresponding EELS of BN nanosheets. (e) AFM tapping mode image of two pieces of large BN nanosheets. (f) 3D view of the marked region in (e). (g) Cross-sectional profile along the scan marked in (e) and (f).
38BN: as a carrier for drug delivery BN has a layered structure similar to graphite. Dopamine is a neurotransmitter which plays an important party in the neural system in human body especially in the brain. In the brain, dopamine is released by nerve cells to act as intermediate to send signals to other receptors. This is why this compound has a critical role in learning ability, memory function, controlling the noise tolerance as well as adjusting the personal character.Required properties:˙ chemically inert˙ nontoxic˙high drug adsorption
39grapheneGraphene is one planar sheet of sp2 -bonded carbon atoms arranged in a hexagonal lattice and is the basis of carbon nanotubes The importance of graphene sheets has been demonstrated in a variety of applications including high electron mobility, and the enhancement of mechanical and electrical properties of composite materials.
43Perovskite Solar CellPervoskitePerovskite structure(ABX3) Ex:CH3NH3PbX3 (X = Cl,Br, I) CH3NH3PbI3-xClxDevice architecturestem from DSSCAu: counter electrode HTM: hole transport CH3NH3PbI3: absorbermesoporous-TiO2: scaffold, electron transport TiO2 compact layer: block the contact between HTM and FTO(hole transport material)TiO2 compact layerlight