Materials Science

Protecting and Connecting

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Science  06 Jun 2003:
Vol. 300, Issue 5625, pp. 1477
DOI: 10.1126/science.300.5625.1477c

Semiconductor nanocrystals or quantum dots consisting of cadmium selenide (CdSe) or telluride (CdTe) are highly fluorescent and thus potentially useful in optical devices and solar cells and as biological labels. A capping ligand or a matrix material is required to stabilize them, but embedding the nanocrystals into a polymer matrix is hard because of incompatibilities between the two materials. Zhang et al. overcome this problem by first capping the CdTe nanocrystals with a surfactant that makes the nanocrystals soluble in styrene. A subsequent polymerization step creates a transparent and still fluorescent CdTe-polystyrene composite. Although nonpolymerizable surfactants produced composites that are opaque and have low photoluminescence (due to the phase separation of the nanocrystals), a mixture of methylmethacrylate and styrene as solvent resulted in CdTe-polymer composites with improved long-term transparency.—MSL

Adv. Mater. 15, 777 (2003).

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