| Autor: |
Sark, W.G.J.H.M. van, Frederix, P.L.T.M., Heuvel, D.J. van den, Asselbergs, M.A.H., Senf, I., Gerritsen, H.C. |
| Zdroj: |
Single Molecules; December 2000, Vol. 1 Issue: 4 p291-298, 8p |
| Abstrakt: |
The dynamic photophysical behaviour of single Cy5- maleimide molecules and core-shell (CdSe)ZnS quantum dots is compared. To this end a home-built fast and sensitive wide-field microscopy system and a scanning confocal microscope coupled to a spectrograph for spectral imaging are employed. The ability to measure time-resolved spectra of quantum dots is shown to be particularly useful in characterizing single quantum dots. The difference in blinking behaviour of single Cy5-maleimide molecules and (CdSe)ZnS quantum dots can be understood by their physical origin, i.e. the presence of a single dark state in case of Cy5 versus a distribution of dark states in case of (CdSe)ZnS. This intrinsic difference results in higher probabilities to find a quantum dot in a short-lived (<0.02 s) or long-lived (>0.2 s) state than a Cy5-mal molecule. Moreover, from a comparison to data in the literature, it was found that the lifetime of the off-state of the Cy5-mal molecule is longer than for the non derivatized Cy5 molecule. |
| Databáze: |
Supplemental Index |
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