Effects of surface passivation on the exciton dynamics of CdSe nanocrystals as observed by ultrafast fluorescence upconversion spectroscopy
| Autor: | Rebecca L. Orndorff, Michael J. Bowers, Tadd Kippeny, James R. McBride, Sandra J. Rosenthal, Maria Danielle Garrett, Albert D. Dukes |
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| Rok vydání: | 2008 |
| Předmět: |
Materials science
Nanostructure Passivation Condensed Matter::Other Exciton General Physics and Astronomy Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Photochemistry Photon upconversion Condensed Matter::Materials Science chemistry.chemical_compound chemistry Nanocrystal Physical and Theoretical Chemistry Methylene Spectroscopy Surface states |
| Zdroj: | The Journal of Chemical Physics. 128:084713 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.2834692 |
| Popis: | The exciton dynamics of CdSe nanocrystals are intimately linked to the surface morphology. Photo-oxidation of the selenium surfaces of the nanocrystal leads to an increase in radiative decay efficiency from both the band edge and deep trap emission states. The addition of the primary amine hexadecylamine curtails nonradiative excitonic decay attributed to the dangling surface selenium orbitals by passivation of those trap sites by the methylene protons on the amine, leading to enhanced band edge emission and the absence of deep trap emission. Furthermore, CdSeZnSe core/shell nanocrystals are not immune from contributions from surface states because of the alignment of the band structures of the core and shell materials. |
| Databáze: | OpenAIRE |
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