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Unformatted text preview: 6-1 Ch. 6 Quantum Dot ResearchObjectives Synthesize a nanoscale material Study absorbance and fluorescence properties of a nanoscale material Learn about methods of measuring nanoscale particle size Atomic Force Microscopy (AFM) Transmission electron microscopy (TEM) Correlate spectral data and microscopic data in determining particle size Overview of Lab In this three-week lab, you will be getting a small taste of the study of material science, including most of the major aspects of this work: synthesis of the material, characterization of the material, and the study of the properties/applications of the material. Week One: Synthesis of nanoscale material Week Two: Spectroscopy of Quantum Dots Absorbance Spectroscopy Correlation of absorbance data to size of quantum dots Fluorescence Spectroscopy Week Three: Non-optical Microscopy Tour of Transmission Electron Microscopy (TEM) Lab Analysis of TEM data Atomic Force Microscopy (AFM) Introduction We take for granted the amazing chemistry that shapes our lives every day in the form of materials. We wear synthetic materials every day. If you have “glasses” you probably don’t wear ones made out of glass; they are typically polycarbonate or other type of plastic. Paints and other coatings protect our possessions against the elements. Fireproof materials protect the Chapter Six 6-2 places we live. It isn’t an overstatement to say that material science affects us directly and almost continually in our society. These classical materials have found broad application, but there are a variety of modern materials that have previously unknown properties with revolutionary applications. Many of these modern materials can be classified as nanoscale materials. The nanoscale is roughly 1-100 nanometers. Materials of this small size have unique properties that allow them to serve as cellular biosensors, drug-delivery devices, solar energy storage systems, data storage devices, nanofilters, and catalysts. Some of the properties are based directly on the small size of the material. For instance, some nanomaterials are great catalysts because their small size maximizes the surface area to volume ratio of the material. Some of the other unique properties, though, are best esxplained by the fact that the properties of these small molecules can be better explained using quantum principles rather than classical physics. In this lab, we will be synthesizing a material made of clusters of atoms of cadmium and selenium. These very small clusters of atoms are on the scale of 2-5 nanometers, meaning that they contain on the order of hundreds or thousands atoms per cluster. These clusters are often called “quantum dots” because they effectively serve as “boxes” that confine electrons. Due to the boxes’ small size, the electronic absorption and emission characteristics behave like molecular semiconductors rather than bulk materials....
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This note was uploaded on 01/18/2012 for the course CHEM S117 taught by Professor Desouza during the Fall '10 term at Indiana.
- Fall '10