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Nanotech News

April 17, 2006

Do-It-Yourself Quantum Dots

Citing a need for an inexpensive method to synthesize quantum dots, researchers at Indiana University-Purdue University in Indianapolis have developed a way to make these highly fluorescent semiconductor nanoparticles that virtually any laboratory can duplicate to create its own quantum dots. The investigators note that this new synthetic approach should provide a boost to efforts aimed at using quantum dots in biomedical research.

Reporting its work in the journal Chemistry of Materials, a team of investigators led by colleagues Christoph Naumann, Ph.D., and Bruce Young, Ph.D., used sound energy to catalyze the formation of cadmium selenide nanoparticles and then added a thin shell of zinc sulfide to form highly luminescent quantum dots. Until now, quantum dots were synthesized using high heat and complex process controls to ensure that the resulting nanoparticles were luminescent and of suitable size.

Characterization of the quantum dots prepared using sonic energy showed that their key optical properties were comparable to commercially available quantum dots. For example, quantum dots prepared using sonic energy were just as bright as those synthesized by conventional methods.

The researchers note that their new method offers two advantages over commercially available quantum dots. The first is price – the new method is so easy to carry out that the resulting quantum dots cost far less than those sold by commercial suppliers. Their low cost should enable more laboratories to explore their use in biomedical research applications. In addition, the mild reaction conditions used in the new technique could enable researchers to add temperature-sensitive molecules to the reaction mixture, which in turn could lead to “one-pot” methods for creating new types of quantum dots that may have their own useful properties.

This work is detailed in a paper titled, “Facile sonochemical synthesis of highly luminescent ZnS-shelled CdSe quantum dots.” This paper was published online in advance of print publication. An abstract of this paper is available at the journal’s website.
View abstract.