Quantum Yield Heterogeneity among Single Nonblinking Quantum Dots Revealed by Atomic Structure-Quantum Optics Correlation
| Autor: | Kemar R. Reid, Noah J. Orfield, James R. McBride, Feng Wang, Sandra J. Rosenthal, Jennifer A. Hollingsworth, Matthew R. Buck, Joseph D. Keene, Han Htoon |
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| Rok vydání: | 2016 |
| Předmět: |
Quantum optics
Photoluminescence Chemistry Exciton General Engineering General Physics and Astronomy Quantum yield 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Nanocrystal Quantum dot Chemical physics General Materials Science Atomic physics 0210 nano-technology Quantum Biexciton |
| Zdroj: | ACS Nano. 10:1960-1968 |
| ISSN: | 1936-086X 1936-0851 |
| Popis: | Physical variations in colloidal nanostructures give rise to heterogeneity in expressed optical behavior. This correlation between nanoscale structure and function demands interrogation of both atomic structure and photophysics at the level of single nanostructures to be fully understood. Herein, by conducting detailed analyses of fine atomic structure, chemical composition, and time-resolved single-photon photoluminescence data for the same individual nanocrystals, we reveal inhomogeneity in the quantum yields of single nonblinking "giant" CdSe/CdS core/shell quantum dots (g-QDs). We find that each g-QD possesses distinctive single exciton and biexciton quantum yields that result mainly from variations in the degree of charging, rather than from volume or structure inhomogeneity. We further establish that there is a very limited nonemissive "dark" fraction (2%) among the studied g-QDs and present direct evidence that the g-QD core must lack inorganic passivation for the g-QD to be "dark". Therefore, in contrast to conventional QDs, ensemble photoluminescence quantum yield is principally defined by charging processes rather than the existence of dark g-QDs. |
| Databáze: | OpenAIRE |
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