scholarly journals Limiting the Growth of Water-Soluble, Monolayer-Protected Quantum Dots

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Ava E. Conner ◽  
Veronica Gordillo-Herrejon ◽  
Sonia C. Francone ◽  
Emily A. Shriner ◽  
Fernando E. Acosta ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Low Temperatures ◽  
Spectral Properties ◽  
Heating Temperature ◽  
Water Soluble ◽  
Heating Process ◽  
Subsequent Growth ◽  
Cdse Qds ◽  
Nanoparticle Growth ◽  
Potential Applications

The growth and solubility of quantum dots (QDs) are important factors that must be examined before these nanoparticles are incorporated into a variety of potential applications. In this work, monolayer-protected CdSe QDs surrounded by water-soluble thiols were prepared using various cadmium salts. The use of a variety of cadmium salts did not have a significant impact on the spectral properties of the CdSe QDs. CdSe QDs were synthesized at rather low temperatures (< 0°C), resulting in slow nanoparticle growth upon subsequent heating of the reaction mixture. The effect of multiple drying and redissolving cycles of the QD samples was examined. The effect of heating temperature on QD growth was studied, with more rapid nanoparticle growth associated with higher temperatures. The results show that QDs can be synthesized at low temperatures and their subsequent growth can be controlled during the heating process.

scholarly journals Synthesis of water-soluble and bio-taggable CdSe@ZnS quantum dots

RSC Advances ◽  
2018 ◽  
Vol 8 (16) ◽  
pp. 8516-8527 ◽  
Author(s):  
G. Ramalingam ◽  
K. Venkata Saravanan ◽  
T. Kayal Vizhi ◽  
M. Rajkumar ◽  
Kathirvelu Baskar
Keyword(s):  
Quantum Dots ◽  
Formation Mechanism ◽  
Water Soluble ◽  
Schematic Diagram ◽  
Cdse Qds

Mystristic capped CdSe QDs with schematic diagram and formation mechanism of bio-taggable CdSe@ZnS QDs.

Optimized Synthesis of Water-Soluble and Small-Size CdSe Quantum Dots

2011 ◽  
Vol 266 ◽  
pp. 46-50
Author(s):  
Jiao Yun Xia ◽  
Jun Long Tang
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Water Soluble ◽  
Cdse Quantum Dots ◽  
Key Factors ◽  
Cdse Qds ◽  
High Quality ◽  
Synthesis Route ◽  
Initial Ph

An optimized synthesis route was applied for controlling the preparation of CdSe quantum dots (QDs) in an aqueous solution. Some key factors which influencing the properties of CdSe QDs, such as initial pH, ratio of precursor etc, were investigated. The as-prepared products have been characterized by TEM, XPS, XRD, UV-Vis and fluorescence (FL) spectra. The result showed that the high-quality CdSe QDs with 3 nm was obtained. The experiments also conformed that the CdSe QDs with better FL properties were obtained with properly initial pH, 5, suitably [Cd2+] / [SeSO3 2-], range from 1:0.25 to 1:0.75 and the ratio of [Cd2+] / [TGA] is 1:2~1:3.

High-Quality Water-Soluble Core/Shell/Shell CdSe/CdS/ZnS Quantum Dots Balanced by Ionic and Nonionic Hydrophilic Capping Ligands

NANO ◽  
2016 ◽  
Vol 11 (07) ◽  
pp. 1650073 ◽  
Author(s):  
Lu Liu ◽  
Hu Xu ◽  
Bing Shen ◽  
Xinhua Zhong
Keyword(s):  
Quantum Dots ◽  
Colloidal Stability ◽  
Water Soluble ◽  
Quantum Yields ◽  
Surface Charges ◽  
Fluorescence Quantum Yields ◽  
Carboxylic Groups ◽  
Potential Applications ◽  
High Fluorescence ◽  
Capping Ligands

Pentaerythritol tetrakis 3-mercaptopropionate (PTMP) grafted poly(acryl acid) (PAA) ionic hydrophilic oligomer PAA-PTMP (PP) and dihydrolipoic acid (DHLA) grafted methoxypoly(ethylene glycol) (mPEG) nonionic hydrophilic oligomer mPEG-DHLA (PD) have been designed, synthesized and used as co-capping ligands in water-solubilization of hydrophobic quantum dots (QDs) via ligand exchange. The obtained oligomers with multi-thiol groups could bind strongly to the surface atoms of QDs. Meanwhile, the carboxyl groups (from PP) and mPEG segment (from PD) can render QDs water-soluble, and the free carboxylic groups can possibly be used for the further bioconjugation. The resulting water-soluble QDs have been characterized by ultraviolet-visible (UV-Vis), fluorescence, Fourier transform infrared (FTIR) spectroscopy as well as transmission electron microscopy (TEM) and dynamic light scattering (DLS) techniques. The water-soluble QDs have relatively small hydrodynamic size (10[Formula: see text]12 nm), and importantly, retain high fluorescence quantum yields (up to 45%) compared with that of the originally hydrophobic QDs (49%). In addition, they have tunable surface charges and show excellent colloidal stability over a relatively broad pH range ([Formula: see text]), in high salt concentration, and even after thermal treatment at 100[Formula: see text]C. These results indicate that the water-soluble QDs coated by PP and PD oligomers have potential applications in cellular imaging and biosensor.

scholarly journals Direct assembly of thioacid capped quantum dots in solid-state hybrid photovoltaics, effect of QDs size and thermal annealing

RSC Advances ◽  
2017 ◽  
Vol 7 (22) ◽  
pp. 13543-13551 ◽  
Author(s):  
Manuel A. Triana ◽  
Oscar A. Jaramillo-Quintero ◽  
Rubén J. Camargo ◽  
Marina E. Rincón
Keyword(s):  
Quantum Dots ◽  
Solar Cells ◽  
Solid State ◽  
Thermal Annealing ◽  
Water Soluble ◽  
Bright Point ◽  
Cdse Qds ◽  
Direct Assembly ◽  
Hybrid Photovoltaics ◽  
Synthesis Yield

The effect of QD size and thermal annealing on water soluble QD solar cells is investigated. CdSe QDs corresponding to the bright-point during synthesis yield the best performance.

Synthesis of High-Performance Aqueous CdSe Quantum Dots Based on Combination of Se Source as Vapor-Phase and Hydrothermal Method

2010 ◽  
Vol 663-665 ◽  
pp. 96-99
Author(s):  
Heng Kang Qiu ◽  
Yue Shen ◽  
Lin Jun Wang ◽  
Jian Cheng Zhang ◽  
Kai Feng Qin
Keyword(s):  
Quantum Dots ◽  
Hydrothermal Method ◽  
Vapor Phase ◽  
High Performance ◽  
Hydrothermal Reaction ◽  
Water Soluble ◽  
Quantum Yields ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Visible Absorption

High performance aqueous CdSe quantum dots (QDs) have been prepared by combination of Se source as vapor-phase and hydrothermal method. The main advantages of this approach included: one is to utilize H2Se vapor as a higher pure selenium source to make the prepared QDs have little other impurities, another is to obtain the QDs with characteristics of more rapid growth in the hydrothermal reaction. The as-prepared products have been characterized by ultraviolet-visible absorption spectra, photoluminescence spectroscopy (PL), X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy dispersive spectroscopy (EDS) analysis etc. The results show the as-synthesized water-soluble CdSe nanoparticles possess higher purity and quantum yields (QY), favorable narrow photoluminescence band with full width of half-maximum (FWHM) down to 40 nm, better photo-stability, and less synthetic time as compared with aqueous CdSe QDs obtained by other methods.

scholarly journals Optical Properties andIn VitroBiological Studies of Oligonucleotide-Modified Quantum Dots

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Valérie A. Gérard ◽  
Mark Freeley ◽  
Eric Defrancq ◽  
Anatoly V. Fedorov ◽  
Yurii K. Gun’ko
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Biological Imaging ◽  
Water Soluble ◽  
Biological Applications ◽  
Potential Applications ◽  
Biochemical Mechanisms

Water-soluble semiconducting nanocrystals or quantum dots (QDs) have attracted much interest in recent years due to their tuneable emission and potential applications in photonics and biological imaging. Fluorescence resonance energy transfer (FRET) processes are very important for elucidating biochemical mechanismsin vitro, and QDs constitute an excellent substrate for this purpose. In this work, new oligonucleotide-functionalised CdTe-based QDs were prepared, characterised and biologically tested. These QDs demonstrated interesting optical properties as well as remarkablein vitrobehaviour and potential for a range of biological applications.

One-Step Synthesis of CdSe Quantum Dots by Using Hydrazine Hydrate Reduction of Selenium Dioxide

2018 ◽  
Vol 71 (7) ◽  
pp. 524 ◽  
Author(s):  
Rongfang Wang ◽  
Xingming Wei ◽  
Jun Xie ◽  
Bomei Wang ◽  
Xiaotong He
Keyword(s):  
Quantum Dots ◽  
Hydrazine Hydrate ◽  
Selenium Dioxide ◽  
Water Soluble ◽  
Molar Ratio ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Original Solution ◽  
Transmission Electron ◽  
Average Size

Hydrazine hydrate was used as a novel reducing agent for the synthesis of water soluble and stable cadmium selenide (CdSe) quantum dots (QDs). The as-prepared CdSe quantum dots were investigated by X-ray powder diffraction, high-resolution transmission electron microscopy, photoluminescence, and UV-vis absorption spectroscopy analyses. The results show that the as-prepared CdSe QDs possess a cubic crystal structure and an average size of 2 nm. The effects of the pH of the original solution, thioglycollic acid (TGA)/Cd2+ molar ratio (nTGA/nCd2+), and the Cd/Se molar ratio on the luminescence properties of CdSe QDs were also systematically analysed.

scholarly journals Study of the Spectral Properties of Nanocomposites with CdSe Quantum Dots in a Wide Range of Low Temperatures

2015 ◽  
Vol 103 ◽  
pp. 09003
Author(s):  
K.A. Magaryan ◽  
I.Y. Eremchev ◽  
K.R. Karimullin ◽  
M.V. Knyazev ◽  
M.A. Mikhailov ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Low Temperatures ◽  
Spectral Properties ◽  
Cdse Quantum Dots ◽  
Wide Range

scholarly journals Water soluble cadmium selenide quantum dots for ultrasensitive detection of organic, inorganic and elemental mercury in biological fluids and live cells

RSC Advances ◽  
2019 ◽  
Vol 9 (39) ◽  
pp. 22274-22281 ◽  
Author(s):  
Siva Bala Subramaniyan ◽  
Anbazhagan Veerappan
Keyword(s):  
Quantum Dots ◽  
Cadmium Selenide ◽  
Biological Fluids ◽  
Elemental Mercury ◽  
Water Soluble ◽  
Live Cells ◽  
Ultrasensitive Detection ◽  
Cdse Qds ◽  
Cadmium Selenide Quantum Dots

CdSe QDs fluorescence is highly selective and sensitive to mercury.

scholarly journals One-Step Synthesis of High-Quality Water-Soluble CdSe Quantum Dots Capped byN-Acetyl-L-cysteineviaHydrothermal Method and Their Characterization

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Chunjin Wei ◽  
Jinyu Li ◽  
Fang Gao ◽  
Shuxia Guo ◽  
Yongcui Zhou ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Photoelectron Spectroscopy ◽  
Ph Value ◽  
Water Soluble ◽  
Molar Ratio ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Hydrothermal Route ◽  
Experimental Conditions ◽  
One Step

Novel water-soluble CdSe quantum dots (QDs) have been prepared withN-acetyl-L-cysteine as new stabilizer through a one-step hydrothermal route. The influence of experimental conditions, including reaction time, molar ratio of reactants, and pH value, on the luminescent properties of the obtained CdSe QDs has been systematically investigated. The characterization of as-prepared QDs was carried out through different methods. In particular, we realized qualitative and semiquantitative studies on CdSe QDs through X-ray photoelectron spectroscopy and electron diffraction spectroscopy. The results show that the as-prepared CdSe QDs exhibit a high quantum yield (up to 26.7%), high stability, and monodispersity and might be widely used in biochemical detection and biochemical research.

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