Gross, Dieter and Susha, Andrei S. and Klar, Thomas A. and Da Como, Enrico and Rogach, Andrey L. and Feldmann, Jochen (2008) Charge separation in type II tunneling structures of close-packed CdTe and CdSe nanocrystals. NANO LETTERS, 8 (5). pp. 1482-1485.
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Official URL: http://dx.doi.org/10.1021/nl080489a
We report on charge separation between type II aligned CdTe and CdSe nanocrystals. Two types of electrostatically bound nanocrystal structures have been studied: first, clusters of nanocrystals hold together by Ca(II) ions in aqueous solution and, second, thin film structures of nanocrystals created with layer-by-layer deposition in combination with polyelectrolytes. In both types of structures, short interparticle distances of less than I nm have been achieved, whereby the isolating organic ligands on the nanocrystal surfaces and/or the polymer monolayers act as tunneling barriers between nanocrystals. We have observed an efficient quenching of photoluminescence and a reduced emission lifetime for CdTe nanocrystals in both types of type II heterostructures. This result is explained by a spatial charge separation of the photoexcited electron-hole pairs due to tunneling of charge carriers through the thin organic layer between CdTe and CdSe nanocrystals. Type II heterostructures demonstrated here may find future applications in photovoltaics.
|Subjects:||Physical Science > Nanophysics|
Material Science > Nanostructured materials
Material Science > Nanochemistry
|Deposited By:||Anuj Seth|
|Deposited On:||09 Dec 2008 14:09|
|Last Modified:||02 Mar 2009 10:31|
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