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Suppressing the Fluorescence Blinking of Single Quantum Dots Encased in N-type Semiconductor Nanoparticles

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ABSTRACT

N-type semiconductor indium tin oxide (ITO) nanoparticles are used to effectively suppress the fluorescence blinking of single near-infrared-emitting CdSeTe/ZnS core/shell quantum dots (QDs), where the ITO could block the electron transfer from excited QDs to trap states and facilitate more rapid regeneration of neutral QDs by back electron transfer. The average blinking rate of QDs is significantly reduced by more than an order of magnitude and the largest proportion of on-state is 98%, while the lifetime is not considerably reduced. Furthermore, an external electron transfer model is proposed to analyze the possible effect of radiative, nonradiative, and electron transfer pathways on fluorescence blinking. Theoretical analysis based on the model combined with measured results gives a quantitative insight into the blinking mechanism.

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(a) Typical fluorescence intensity trajectories for the single QDs on glass coverslips and encased in ITO, respectively. The blue trajectory represents fluorescence intensity of single QD on glass coverslip and the red trajectory represents fluorescence intensity of single QD encased in ITO; the silver-gray trajectories represent background; the corresponding fluorescence intensity distribution is shown in the right panels. (b) Histograms of blinking rates for ~110 studied single QDs on glass coverslips and encased in ITO, respectively. (c) Histograms of proportion of on-state for ~110 studied single QDs on glass coverslips and encased in ITO, respectively.
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f1: (a) Typical fluorescence intensity trajectories for the single QDs on glass coverslips and encased in ITO, respectively. The blue trajectory represents fluorescence intensity of single QD on glass coverslip and the red trajectory represents fluorescence intensity of single QD encased in ITO; the silver-gray trajectories represent background; the corresponding fluorescence intensity distribution is shown in the right panels. (b) Histograms of blinking rates for ~110 studied single QDs on glass coverslips and encased in ITO, respectively. (c) Histograms of proportion of on-state for ~110 studied single QDs on glass coverslips and encased in ITO, respectively.

Mentions: The fluorescence intensity trajectories for single QDs on glass coverslips and encased in ITO were recorded by the confocal scanning fluorescence microscope system. Figure 1a shows two typical fluorescence intensity trajectories and corresponding fluorescence intensity histograms for single QDs on glass coverslips and encased in ITO, respectively. The trajectories were recorded with an integration time of 100 ms. It is found in the upper part of Fig. 1a that the fluorescence of single QDs on glass coverslips shows a quite strong blinking and the corresponding intensity histogram mainly lies on dark state. Compared with the results on glass coverslips, single QDs in ITO have less fluorescence blinking, and the corresponding intensity histogram mainly lies on bright state, as shown in the lower part of Fig. 1a.


Suppressing the Fluorescence Blinking of Single Quantum Dots Encased in N-type Semiconductor Nanoparticles
(a) Typical fluorescence intensity trajectories for the single QDs on glass coverslips and encased in ITO, respectively. The blue trajectory represents fluorescence intensity of single QD on glass coverslip and the red trajectory represents fluorescence intensity of single QD encased in ITO; the silver-gray trajectories represent background; the corresponding fluorescence intensity distribution is shown in the right panels. (b) Histograms of blinking rates for ~110 studied single QDs on glass coverslips and encased in ITO, respectively. (c) Histograms of proportion of on-state for ~110 studied single QDs on glass coverslips and encased in ITO, respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5015025&req=5

f1: (a) Typical fluorescence intensity trajectories for the single QDs on glass coverslips and encased in ITO, respectively. The blue trajectory represents fluorescence intensity of single QD on glass coverslip and the red trajectory represents fluorescence intensity of single QD encased in ITO; the silver-gray trajectories represent background; the corresponding fluorescence intensity distribution is shown in the right panels. (b) Histograms of blinking rates for ~110 studied single QDs on glass coverslips and encased in ITO, respectively. (c) Histograms of proportion of on-state for ~110 studied single QDs on glass coverslips and encased in ITO, respectively.
Mentions: The fluorescence intensity trajectories for single QDs on glass coverslips and encased in ITO were recorded by the confocal scanning fluorescence microscope system. Figure 1a shows two typical fluorescence intensity trajectories and corresponding fluorescence intensity histograms for single QDs on glass coverslips and encased in ITO, respectively. The trajectories were recorded with an integration time of 100 ms. It is found in the upper part of Fig. 1a that the fluorescence of single QDs on glass coverslips shows a quite strong blinking and the corresponding intensity histogram mainly lies on dark state. Compared with the results on glass coverslips, single QDs in ITO have less fluorescence blinking, and the corresponding intensity histogram mainly lies on bright state, as shown in the lower part of Fig. 1a.

View Article: PubMed Central - PubMed

ABSTRACT

N-type semiconductor indium tin oxide (ITO) nanoparticles are used to effectively suppress the fluorescence blinking of single near-infrared-emitting CdSeTe/ZnS core/shell quantum dots (QDs), where the ITO could block the electron transfer from excited QDs to trap states and facilitate more rapid regeneration of neutral QDs by back electron transfer. The average blinking rate of QDs is significantly reduced by more than an order of magnitude and the largest proportion of on-state is 98%, while the lifetime is not considerably reduced. Furthermore, an external electron transfer model is proposed to analyze the possible effect of radiative, nonradiative, and electron transfer pathways on fluorescence blinking. Theoretical analysis based on the model combined with measured results gives a quantitative insight into the blinking mechanism.

No MeSH data available.


Related in: MedlinePlus