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2005
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In the Laboratory
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A Safer, Easier, Faster Synthesis for CdSe Quantum Dot Nanocrystals
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Elizabeth M. Boatman and George C. Lisensky
Department of Chemistry, Beloit College, Beloit, WI 53511Karen J. Nordell
Department of Chemistry, Lawrence University, Appleton, WI 54912
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November 2005
Vol. 82 No. 11
p. 1697
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| Abstract |
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Properties that vary with particle size are an important feature of nanoscale materials. CdSe quantum dot nanocrystals vary in color from green–yellow to orange–red and luminesce from blue to yellow, where shorter wavelength, higher energy, electronic transitions correspond to smaller particle sizes. CdSe quantum dot nanocrystals are a visually engaging way to demonstrate quantum effects in chemistry, since their transition energies can be explained as a "particle in a box", where a delocalized electron is the particle and the nanocrystal is the box. Following the method pioneered by Xiaogang Peng and coworkers, CdSe nanocrystals are synthesized from CdO, oleic acid, elemental Se, and trioctylphosphine using a kinetic growth method in octadecene at 225 °C and a less than three-minute reaction time. This synthesis has several advantages over methods using dimethyl cadmium, a chemical that is extremely toxic, expensive, unstable, pyrophoric, and requires inert atmosphere techniques. When excited at 400 nm, the colloidal suspensions of quantum dots give relatively sharp emission spectra with ∼35-nm peak widths, indicating monodisperse particle sizes. Corresponding absorbance spectra are also of high quality.
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| Supplement |
Instructions for the students and notes for the instructor are available
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| More Information |
Citation |
Boatman, Elizabeth M.; Lisensky, George C.; Nordell, Karen J. J. Chem. Educ. 2005 82 1697.
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Keywords |
Cadmium; Colloids; Fluorescence Spectroscopy; Hands-On Learning / Manipulatives; Inorganic Chemistry; Laboratory Instruction; Nanotechnology; Physical Chemistry; Selenium; Upper-Division Undergraduate; UV-Vis Spectroscopy
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History |
Created:
Last Updated: |
9/22/2005
9/29/2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
2005
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November
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1697
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