MATERIALS SCIENCE: A Brighter Future by Working Together

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Science  19 Nov 2004:
Vol. 306, Issue 5700, pp. 1263a
DOI: 10.1126/science.306.5700.1263a

Both metal nanoparticles and semiconducting nanowires have interesting optical and electrical properties, but what happens when they are coupled together? Lee et al. try to answer this question for a collection of CdTe nanowires that are complexed with Au nanoparticles using the biotin-streptavidin ligand-receptor pair to connect the two together.

When these components were mixed in solution, the authors observed a fivefold increase in the peak luminescence intensity and a blue shift of the spectra that developed gradually with time. Surprisingly, as the intensity increased, the photoluminescence lifetime decreased, which is in contrast to normally observed trends. The authors interpreted their observations within a model in which the Au nanoparticles form a coaxial shell around the nanowires. They find that the gold particles generate an electro-magnetic field that stimulates photon emission from the nanowires, in a process that is reminiscent of surface-enhanced Raman scattering. This effect is not due to individual nanoparticle-nanowire interactions but instead to the collective effect of the aggregated metallic nanoparticles. — MSL

Nano Lett. 10.1021/nl048669h (2004).

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