Single-Molecule Colocalization Studies Shed Light on the Idea of Fully Emitting versus Dark Single Quantum Dots

Small ◽  
2011 ◽  
Vol 7 (14) ◽  
pp. 2101-2108 ◽  
Author(s):  
Thomas Pons ◽  
Igor L. Medintz ◽  
Dorothy Farrell ◽  
Xiang Wang ◽  
Amy F. Grimes ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Single Molecule ◽  
Single Quantum ◽  
Single Quantum Dots ◽  
Shed Light

scholarly journals Room temperature excitation spectroscopy of single quantum dots

2011 ◽  
Vol 2 ◽  
pp. 516-524 ◽  
Author(s):  
Christian Blum ◽  
Frank Schleifenbaum ◽  
Martijn Stopel ◽  
Sébastien Peter ◽  
Marcus Sackrow ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Single Molecule ◽  
Room Temperature ◽  
Cdse Nanocrystals ◽  
Photoluminescence Excitation ◽  
Single Quantum ◽  
Excitation Spectra ◽  
Detection Scheme ◽  
Single Quantum Dots ◽  
The Individual

We report a single molecule detection scheme to investigate excitation spectra of single emitters at room temperature. We demonstrate the potential of single emitter photoluminescence excitation spectroscopy by recording excitation spectra of single CdSe nanocrystals over a wide spectral range of 100 nm. The spectra exhibit emission intermittency, characteristic of single emitters. We observe large variations in the spectra close to the band edge, which represent the individual heterogeneity of the observed quantum dots. We also find specific excitation wavelengths for which the single quantum dots analyzed show an increased propensity for a transition to a long-lived dark state. We expect that the additional capability of recording excitation spectra at room temperature from single emitters will enable insights into the photophysics of emitters that so far have remained inaccessible.

scholarly journals Distance dependence of near-field fluorescence enhancement and quenching of single quantum dots

2011 ◽  
Vol 2 ◽  
pp. 645-652 ◽  
Author(s):  
Volker Walhorn ◽  
Jan Paskarbeit ◽  
Heinrich Gotthard Frey ◽  
Alexander Harder ◽  
Dario Anselmetti
Keyword(s):  
Quantum Dots ◽  
Fluorescence Microscopy ◽  
Single Molecule ◽  
Dipolar Coupling ◽  
Near Field ◽  
Fluorescence Emission ◽  
Field Enhancement ◽  
Single Quantum ◽  
Distance Dependence ◽  
Single Quantum Dots

In fluorescence microscopy and spectroscopy, energy transfer processes between single fluorophores and fluorophore quencher pairs play an important role in the investigation of molecular distances or orientations. At distances larger than about 3 nm these effects originate predominantly from dipolar coupling. As these experiments are commonly performed in homogenous media, effects at the interface boundaries can be neglected. Nevertheless, the combination of such assays with single-molecule manipulation techniques such as atomic force microscopy (AFM) requires a detailed understanding of the influence of interfaces on dipolar coupling effects. In the presented work we used a combined total internal reflection fluorescence microscopy (TIRFM)–AFM setup to elucidate this issue. We measured the fluorescence emission emanating from single quantum dots as a function of distance from the apex of a gold-coated cantilever tip. As well as fluorescence quenching at close proximity to the tip, we found a nonlinear and nonmonotonic distance dependence of the fluorescence emission. To confirm and interpret our findings we performed calculations on the basis of a simplified multiple multipole (MMP) approach, which successfully supports our experimental data. Moreover, we revealed and quantified the influence of interfering processes such as field enhancement confined at interface boundaries, mirror dipoles and (resonant) dipolar coupling.

scholarly journals Electrochemically Controlled Deconjugation and Delivery of Single Quantum Dots into the Nucleus of Living Cells

Small ◽  
2010 ◽  
Vol 6 (19) ◽  
pp. 2109-2113 ◽  
Author(s):  
Kyungsuk Yum ◽  
Ning Wang ◽  
Min-Feng Yu
Keyword(s):  
Quantum Dots ◽  
Living Cells ◽  
Single Quantum ◽  
Single Quantum Dots

Towards a single-mode single photon source based on single quantum dots

2001 ◽  
Vol 94-95 ◽  
pp. 797-803 ◽  
Author(s):  
I. Robert ◽  
E. Moreau ◽  
J.M. Gérard ◽  
I. Abram
Keyword(s):  
Quantum Dots ◽  
Single Photon ◽  
Single Mode ◽  
Single Quantum ◽  
Single Photon Source ◽  
Single Quantum Dots ◽  
Photon Source

Однофотонное излучение одиночной квантовой точки CdTeSe/ZnS в ближнем инфракрасном диапазоне при комнатной температуре

2021 ◽  
Vol 47 (21) ◽  
pp. 3
Author(s):  
Siyue Jin ◽  
Xingsheng Xu
Keyword(s):  
Quantum Dots ◽  
Room Temperature ◽  
Auger Recombination ◽  
Single Photon ◽  
Irradiation Time ◽  
Colloidal Quantum Dots ◽  
Single Quantum ◽  
Illumination Time ◽  
Single Quantum Dots ◽  
Single Quantum Dot

In this study, the photostability of a CdTeSe/ZnS colloidal single photon emitter with a wavelength of 800nm at room temperature was investigated. The second-order correlation function was much smaller than 0.1, which proved that the CdTeSe/ZnS single quantum dot at 800nm is a highly pure single-photon emitter. The effects of the irradiation time on the optical properties from single quantum dots were analyzed. As the illumination time increased, the emission of biexciton and multiexciton in the colloidal quantum dots increased, and the occurrence of Auger recombination increased.

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