scholarly journals Measuring anti-bunching Effect from Single Dye Molecules and Single Quantum Dots

2016 ◽  
Vol 26 (1) ◽  
pp. 67
Author(s):  
Nguyen Thi Thanh Bao ◽  
Dinh Van Trung ◽  
Dang Tuyet Phuong
Keyword(s):  
Quantum Dots ◽  
Single Molecule ◽  
Fluorescence Lifetime ◽  
Rhodamine B ◽  
Quantum Effect ◽  
Direct Proof ◽  
Second Order ◽  
Cdte Quantum Dots ◽  
Dye Molecules ◽  
Antibunching Effect

Antibunching is a quantum effect demonstrating clearly the quantum nature of the radiation field. Its detection through measurements of the second order correlation function is a direct proof of the presence of single molecule or single nano particle. In this paper we present the experimental setup of the Hanbury Brown - Twiss interferometer and the measurement results of the antibunching effect from single Rhodamine B dye molecules and single CdTe quantum dots in dilute solution. By fitting the second order correlation data, we derive a fluorescence lifetime of approximately 2 ns for Rhodamine B and 45 ns for CdTe quantum dots. Our results demonstrate an alternative way for determining the fluorescence lifetime using the antibunching effect.

High-Sensitivity Fluorescence Lifetime Thermal Sensing Based on CdTe Quantum Dots

Small ◽  
2012 ◽  
Vol 8 (17) ◽  
pp. 2652-2658 ◽  
Author(s):  
P. Haro-González ◽  
L. Martínez-Maestro ◽  
I. R. Martín ◽  
J. García-Solé ◽  
D. Jaque
Keyword(s):  
Quantum Dots ◽  
Fluorescence Lifetime ◽  
High Sensitivity ◽  
Cdte Quantum Dots ◽  
Thermal Sensing

scholarly journals Dual-Emission Fluorescence Probe Based on CdTe Quantum Dots and Rhodamine B for Visual Detection of Mercury and Its Logic Gate Behavior

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 713
Author(s):  
Yuefeng Gao ◽  
Sai Xu ◽  
Zhijian Liu ◽  
Kezhen Yu ◽  
Xinxiang Pan
Keyword(s):  
Quantum Dots ◽  
Rhodamine B ◽  
Visual Detection ◽  
Fluorescence Probe ◽  
Limit Of Detection ◽  
Logic Gate ◽  
Cdte Quantum Dots ◽  
Fluorescence Signal ◽  
Dual Emission ◽  
Cdte Qds

It is urgent that a convenient and sensitive technique of detecting Hg2+ be developed because of its toxicity. Conventional fluorescence analysis works with a single fluorescence probe, and it often suffers from signal fluctuations which are influenced by external factors. In this research, a novel dual-emission probe assembled through utilizing CdTe quantum dots (QDs) and rhodamine B was designed to detect Hg2+ visually. Only the emission of CdTe QDs was quenched after adding Hg2+ in the dual-emission probe, which caused an intensity ratio change of the two different emission wavelengths and hence facilitated the visual detection of Hg2+. Compared to single emission QDs-based probe, a better linear relationship was shown between the variation of fluorescence intensity and the concentration of Hg2+, and the limit of detection (LOD) was found to be11.4 nM in the range of 0–2.6 μM. Interestingly, the intensity of the probe containing Hg2+ could be recovered in presence of glutathione (GSH) due to the stronger binding affinity of Hg2+ towards GSH than that towards CdTe QDs. Based on this phenomenon, an IMPLICATION logic gate using Hg2+/GSH as inputs and the fluorescence signal of QDs as an output was constructed.

Fluorescenсе Properties of Complexes of Coumarin Derivatives/CdTe Quantum Dots under Interaction with Ammonia Molecules in Microconcentrations

2016 ◽  
Vol 8 (4(1)) ◽  
pp. 04032-1-04032-5
Author(s):  
V. P. Mitsai ◽  
◽  
A. G. Misyura ◽  
S. V. Kryvets ◽  
Ya. P. Lazorenko ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Cdte Quantum Dots ◽  
Coumarin Derivatives

scholarly journals Silver Nanoparticles Functionalized by Fluorescein Isothiocyanate or Rhodamine B Isothiocyanate: Fluorescent and Plasmonic Materials

2021 ◽  
Vol 11 (6) ◽  
pp. 2472
Author(s):  
Ilaria Fratoddi ◽  
Chiara Battocchio ◽  
Giovanna Iucci ◽  
Daniele Catone ◽  
Antonella Cartoni ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
Transient Absorption ◽  
Fluorescein Isothiocyanate ◽  
Dye Molecules ◽  
Chemical Surface ◽  
Vis Spectroscopy ◽  
Rhodamine B Isothiocyanate ◽  
Fluorescent Molecules

This paper presents the synthesis of silver nanoparticles (AgNPs) functionalized with fluorescent molecules, in particular with xanthene-based dyes, i.e., fluorescein isothiocyanate (FITC, λmax = 485 nm) and rhodamine B isothiocyanate (RITC, λmax = 555 nm). An in-depth characterization of the particle–dye systems, i.e., AgNPs–RITC and AgNPs–FITC, is presented to evaluate their chemical structure and optical properties due to the interaction between their plasmonic and absorption properties. UV–Vis spectroscopy and the dynamic light scattering (DLS) measurements confirmed the nanosize of the AgNPs–RITC and AgNPs–FITC. Synchrotron radiation X-ray photoelectron spectroscopy (SR-XPS) was used to study the chemical surface functionalization by structural characterization, confirming/examining the isothiocyanate–metal interaction. For AgNPs–RITC, in which the plasmonic and fluorescence peak are not superimposed, the transient dynamics of the dye fluorescence were also studied. Transient absorption measurements showed that by exciting the AgNPs–RITC sample at a wavelength corresponding to the AgNP plasmon resonance, it was possible to preferentially excite the RITC dye molecules attached to the surface of the NPs with respect to the free dye molecules in the solution. These results demonstrate how, by combining plasmonics and fluorescence, these AgNPs can be used as promising systems in biosensing and imaging applications.

Electrostatic repulsion strategy for highly selective and sensitive “switch–on” fluorescence sensor of ascorbic acid based on the cysteamine-coated CdTe quantum dots and cerium (IV)

2021 ◽  
Author(s):  
Yifei Guo ◽  
Jingjing Du ◽  
Jianjun Li ◽  
Ran Yang ◽  
Peter B. de Harrington ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ascorbic Acid ◽  
Hydrothermal Method ◽  
Cadmium Chloride ◽  
Fluorescence Sensor ◽  
Cdte Quantum Dots ◽  
Electrostatic Repulsion ◽  
Functional Monomer ◽  
Simple Hydrothermal Method ◽  
Cdte Qds

In this work, cysteamine-coated CdTe quantum dots (CA-CdTe QDs) were synthesized by a simple hydrothermal method employing cadmium chloride as the cadmium source and cysteamine hydrochloride as the functional monomer....

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