Dynamic fluctuations in ultrasmall nanocrystals induce white light emission.

Pennycook TJ, McBride JR, Rosenthal SJ, Pennycook SJ, Pantelides ST
Nano Lett. 2012 12 (6): 3038-42

PMID: 22568665 · DOI:10.1021/nl3008727

Individual ultrasmall CdSe nanocrystals have recently been found to emit white light, but the ultimate origin of the phenomenon has remained elusive. Here we use a combination of state-of-the-art experiment and theory to show that excitation sets the ultrasmall nanocrystals into a fluxional state. Their energy gaps vary continuously on a femtosecond time scale, so that even an individual nanocrystal can emit across the entire visual range. In addition, we observe the outer layers of the larger monochromatic emitting nanocrystals to be fluxional. Such fluxionality should be considered when optimizing nanocrystals for applications. Thus, small is indeed different, but ultrasmall is different yet again.

MeSH Terms (7)

Cadmium Compounds Color Lighting Materials Testing Nanostructures Particle Size Selenium Compounds

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