Global ETD Search

1	Detecting single-particle insulating collisions in microfluidics as a function of flow rate Nettleton, Elizabeth Grace 27 February 2013 (has links) This work presents the first electrochemical observation of single polystyrene microbead collisions with an electrode within a microchannel. We have observed that detecting single microbead collisions is facile with this system. Additionally, we have shown that by increasing flow within the channel, one can increase both the frequency and magnitude of collision signals. This technique may provide a means of signal amplification in future sensing work. / text Electrochemistry Microfluidics Sensing Collisions Single-particle detection
2	Photoinduced hole trapping in single semiconductor quantum dots at specific sites at silicon oxide interfaces Krasselt, Cornelius, Schuster, Jörg, von Borczyskowski, Christian 23 September 2013 (has links) (PDF) Blinking dynamics of CdSe/ZnS semiconductor quantum dots (QD) are characterized by (truncated) power law distributions exhibiting a wide dynamic range in probability densities and time scales both for off- and on-times. QDs were immobilized on silicon oxide surfaces with varying grades of hydroxylation and silanol group densities, respectively. While the off-time distributions remain unaffected by changing the surface properties of the silicon oxide, a deviation from the power law dependence is observed in the case of on-times. This deviation can be described by a superimposed single exponential function and depends critically on the local silanol group density. Furthermore, QDs in close proximity to silanol groups exhibit both high average photoluminescence intensities and large on-time fractions. The effect is attributed to an interaction between the QDs and the silanol groups which creates new or deepens already existing hole trap states within the ZnS shell. This interpretation is consistent with the trapping model introduced by Verberk et al. (R. Verberk, A. M. van Oijen and M. Orrit, Phys. Rev. B, 2002, 66, 233202). Lumineszenz-Unterbrechung Blinking Halbleiter Quantenpunkt Nanopartikel CdSe/ZnS Einzelteilchen-Detektion Siliziumoxid trap Zustände Loch trapping Photoluminescence intermittency semiconductor quantum dots CdSe/ZnS single particle detection silicon oxide trap states hole trapping ddc:539 Halbleiter Quantenpunkt Nanopartikel
3	Photoinduced hole trapping in single semiconductor quantum dots at specific sites at silicon oxide interfaces Krasselt, Cornelius, Schuster, Jörg, von Borczyskowski, Christian 23 September 2013 (has links) Blinking dynamics of CdSe/ZnS semiconductor quantum dots (QD) are characterized by (truncated) power law distributions exhibiting a wide dynamic range in probability densities and time scales both for off- and on-times. QDs were immobilized on silicon oxide surfaces with varying grades of hydroxylation and silanol group densities, respectively. While the off-time distributions remain unaffected by changing the surface properties of the silicon oxide, a deviation from the power law dependence is observed in the case of on-times. This deviation can be described by a superimposed single exponential function and depends critically on the local silanol group density. Furthermore, QDs in close proximity to silanol groups exhibit both high average photoluminescence intensities and large on-time fractions. The effect is attributed to an interaction between the QDs and the silanol groups which creates new or deepens already existing hole trap states within the ZnS shell. This interpretation is consistent with the trapping model introduced by Verberk et al. (R. Verberk, A. M. van Oijen and M. Orrit, Phys. Rev. B, 2002, 66, 233202). info:eu-repo/classification/ddc/539 ddc:539 Halbleiter; Quantenpunkt; Nanopartikel

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