All in the Dope

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Science  09 Dec 2005:
Vol. 310, Issue 5754, pp. 1589
DOI: 10.1126/science.310.5754.1589a

Cadmium selenide nanoparticles are used in light-emitting diodes, lasers, and sensors and for biological labeling. However, the toxicity of cadmium is a major concern. Zinc chalcogenides, such as ZnSe, doped with transition metal ions may offer as much flexibility and dynamic range as CdSe, but it has been difficult to dope particles uniformly. Recent success in separating the nucleation and growth phases in making high-quality nanoparticles prompted Pradhan et al. to consider whether efficient and controlled doping could be introduced. For growth-stage doping, seed ZnSe particles were quenched, and copper was then added as a dopant. Overgrowth with additional ZnSe shifted the photoluminescence (PL) toward the red wavelengths. For the nucleation strategy, Mn was added to shift the PL even further toward the red. The nanoparticle syntheses were performed as one-pot reactions so control of the doping relative to the nucleation or growth could be achieved by varying the reactivity of the precursors and the temperature. — MSL

J. Am. Chem. Soc.10.1021/ja055557z (2005).

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