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Quantum Dots: The Disco Lights of the Nanomaterial World. By Marcus Fuentes. Texas A&M University Kingsville. What is a Quantum Dot. Special Semiconductor that emits light It comes in an assortment of sizes Sizes determine the color of light is seen. Old Mc Donald Raised Some Dots.
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Quantum Dots: The Disco Lights of the Nanomaterial World By Marcus Fuentes Texas A&M University Kingsville
What is a Quantum Dot • Special Semiconductor that emits light • It comes in an assortment of sizes • Sizes determine the color of light is seen
Old Mc Donald Raised Some Dots • Some quantum dots are formed because a small region of one material burring in another with a larger band gap • Some form spontaneously in quantum well structures • A few self assembled form a nucleus spontaneously • And some can be created from two dimensional electrons or gases present in remotely doped quantum wells or semiconductor heterostructures
Colloidal synthesis is the cheapest and least toxic • Electrochemical techniques involve templates that are created by an ionic reaction that in turn create quantum dots • Pyrolytic synthesis involves the production of large numbers of quantum dots that self-assemble into preferential crystal sizes
Look at what I can do • Detection of tumors • Used as a substitute for organic dyes • Silicon photovoltaic cells • Light-emitting diodes and other light sources • Used to battle counterfeit money Drawbacks • Toxicity • High cost of manufacturing • Unable to accurately predict
Conclusion • Quantum dot is an iridescent nanomaterial • Fabrication is expensive • New applications found everyday • Growing advantages in the medical field • Manufacturing is random and toxicity is a possibility
References Reed MA, Randall JN, Aggarwal RJ, Matyi RJ, Moore TM, Wetsel AE (1988). "Observation of discrete electronic states in a zero-dimensional semiconductor nanostructure". Phys Rev Lett60 (6): 535-537. PMID 10038575. (1988).[1] Reed MA (1993). "Quantum Dots" (PDF). Scientific American 268 (1): 118. Murray CB, Norris DJ, Bawendi MG (1993). "Synthesis and characterization of nearly monodisperseCdE (E = S, Se, Te) semiconductor nanocrystallites" (PDF). J Am Chem Soc 115: 8706-15. Peng ZA, Peng X (2001). "Formation of high-quality CdTe, CdSe, and CdSnanocrystals using CdO as precursor" (PDF). J Am Chem Soc 123: 183-4. Wang C, Shim M, Guyot-Sionnest P (2001). "Electrochromicnanocrystal quantum dots" (PDF). Science 291: 2390-2. Michalet X, Pinaud FF, Bentolila LA, et al (2005). "Quantum dots for live cells, in vivo imaging, and diagnostics". Science 307 (5709): 538-44. DOI:10.1126/science.1104274. PMID 15681376. Shim M, Guyot-Sionnest P (2000). "n-type colloidal semiconductor nanocrystals" (PDF). Nature 407 (6807): 981-3. DOI:10.1038/35039577. PMID 11069172. Buhro WE, Colvin VL (2003). "Semiconductor nanocrystals: Shape matters". Nature materials 2 (3): 138-9. DOI:10.1038/nmat844. PMID 12612665. Bandyopadhyay S, Miller AE (2001). "Electrochemically self-assembled ordered nanostructure arrays: Quantum dots, dashes, and wires", in Nalwa HS: Handbook of Advanced Electronic and Photonic Materials and Devices. ISBN 0125137451. Schaller RD, Klimov VI (2004). "High Efficiency Carrier Multiplication in PbSeNanocrystals: Implications for Solar Energy Conversion". Phys Rev Lett92 (18): 186601. DOI:10.1103/PhysRevLett.92.186601. Bowers MJ, McBride JR, Rosenthal SJ. "White-Light Emission from Magic-Sized Cadmium SelenideNanocrystals". J Am Chem Soc 127 (44): 15378-9. DOI:S0002-7863(05)05470-3 10.1021/ja055470d S0002-7863(05)05470-3.