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.

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.

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.

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 Investigation on Surface Properties of Mn-Doped CdSe Quantum Dots Studied by X-ray Photoelectron Spectroscopy

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1250 ◽  
Author(s):  
Hamizi ◽  
Johan ◽  
Abdul Wahab ◽  
Chowdhury ◽  
Akbarzadeh Pivehzhani ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Binding Energy ◽  
Cadmium Selenide ◽  
Photoelectron Spectroscopy ◽  
Organic Ligand ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
X Ray ◽  
Inverse Micelle ◽  
Mn Doped

In this work, we report on the effects of incorporating manganese (Mn) dopant into different sizes of cadmium selenide (CdSe) quantum dots (QDs), which improves the electronic and optical properties of the QDs for multiple applications such as light-emitting diodes, lasers, and biological labels. Furthermore, the greener inverse Micelle method was implemented using organic ligand, which is oleic acid. This binding of the surface enhanced the QDs’ surface trap passivation of Mn-doped CdSe, which then increased the quantity of the output. In addition, the inverse Micelle technique was used successfully to dope Mn into CdSe QDs without the risk of Mn dopants being self-purified as experienced by wurtzite CdSe QDs. Also, we report the X-ray photoelectron spectroscopy (XPS) results and analysis of zinc blended manganese-doped cadmium selenide quantum dots (Mn-doped CdSe QDs), which were synthesized with physical sizes that varied from 3 to 14 nm using the inverse Micelle method. The XPS scans traced the existence of the Se 3d and Cd 3d band of CdSe crystals with a 54.1 and 404.5 eV binding energy. The traced 640.7 eV XPS peak is proof that Mn was integrated into the lattice of CdSe QDs. The binding energy of the QDs was related to the increase in the size of the QDs.

Investigation of Factors Induced the Non-Intrinsic Optical Properties for Water-Soluble CdSe Semiconductor Quantum Dots

2010 ◽  
Vol 663-665 ◽  
pp. 437-440
Author(s):  
Heng Kang Qiu ◽  
Yue Shen ◽  
Lin Jun Wang ◽  
Jian Cheng Zhang ◽  
Kai Feng Qin
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Photoelectron Spectroscopy ◽  
Semiconductor Quantum Dots ◽  
Water Soluble ◽  
Nano Particles ◽  
Crystal Nucleation ◽  
Band Edge ◽  
Molar Ratio ◽  
X Ray

For the purpose of investigating the factors induced the non-band-edge excitation optical properties of water-soluble CdSe semiconductor quantum dots (QDs), the initial molar ratio of Cd and Se(or Cd/Se), the temperature of crystal nucleation and growing, the time of the growth etc. are systematically studied in the fabricated process. The properties of the as-prepared nano-particles (NPs) have been characterized by ultraviolet-visible absorption spectra (UV-Vis), photoluminescence (PL) spectroscopy, X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), and X-ray photoelectron spectroscopy (XPS). The measured results show that it is possible to exist surface trapping, impurities and other defect energy states in the products with the non-band-edge excitation PL properties, and all the characteristics are involved with the different synthetic routes and prepared techniques.

A simple one-step hydrothermal route towards water solubilization of carbon quantum dots from soya-nuggets for imaging applications

RSC Advances ◽  
2015 ◽  
Vol 5 (106) ◽  
pp. 87528-87534 ◽  
Author(s):  
Prashant Dubey ◽  
Kumud Malika Tripathi ◽  
Ragini Mishra ◽  
Anshu Bhati ◽  
Anupriya Singh ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Hydrothermal Process ◽  
Carbon Quantum Dots ◽  
Single Step ◽  
Water Soluble ◽  
High Yield ◽  
Synthetic Approach ◽  
Hydrothermal Route ◽  
E Coli ◽  
One Step

A high yield simple synthetic approach for water soluble photoluminescent carbon quantum dots via a single step, hydrothermal process, was described. Photoluminescent multi-colored emissions were used to label E. coli cells.

scholarly journals A Novel Approach to the Fabrication of CdSe Quantum Dots in Aqueous Solution: Procedures for Controlling Size, Fluorescence Intensity, and Stability over Time

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
M. J. Almendral-Parra ◽  
A. Alonso-Mateos ◽  
J. F. Boyero-Benito ◽  
S. Sánchez-Paradinas ◽  
E. Rodríguez-Fernández
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Mercaptoacetic Acid ◽  
Quantum Yields ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Experimental Conditions ◽  
Synthesis Of Nanoparticles ◽  
Novel Approach ◽  
High Fluorescence

This paper report a straightforward approach for the synthesis of CdSe quantum dots (CdSe QDs) in aqueous solution. This method, performed in homogeneous phase, affords optimal sizes and high quantum yields for each application desired. It is ana la carteprocedure for the synthesis of nanoparticles aimed at their later application. By controlling the experimental conditions, CdSe QDs of sizes ranging between 2 and 6 nm can be obtained. The best results were achieved in an ice-bath thermostated at 4°C, using mercaptoacetic acid as dispersant. Under these conditions, a slow growth of quantum nanocrystals was generated and this was controlled kinetically by the hydrolysis ofSeSO32-to generateSe2-  in situ, one of the forming species of the nanocrystal. The organic dispersant mercaptoacetate covalently binds to the Cd2+ion, modifying the diffusion rate of the cation, and plays a key role in the stabilization of CdSe QDs. In optimum conditions, when kept in their own solution CdSe QDs remain dispersed over 4 months. The NPs obtained under optimal conditions show high fluorescence, which is a great advantage as regards their applications. The quantum efficiency is also high, owing to the formation under certain conditions of ananoshellof Cd(OH)2, values of 60% being reached.

scholarly journals Size Dependent Optical Nonlinearity and Optical Limiting Properties of Water Soluble CdSe Quantum Dots

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Anju K. Augustine ◽  
S. Mathew ◽  
P. Radhakrishnan ◽  
V. P. N. Nampoori ◽  
M. Kailasnath
Keyword(s):  
Quantum Dots ◽  
Nonlinear Behavior ◽  
Optical Limiting ◽  
Optical Nonlinearity ◽  
Water Soluble ◽  
Saturable Absorption ◽  
Reverse Saturable Absorption ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
High Laser

We present third-order optical nonlinear absorption in CdSe quantum dots (QDs) with particle sizes in the range of 4.16–5.25 nm which has been evaluated by the Z-scan technique. At an excitation irradiance of 0.54 GW/cm2 the CdSe QDs exhibit reverse saturation indicating a clear nonlinear behavior. Nonlinearity increases with particle size in CdSe QDs within the range of our investigations which in turn depends on the optical band gap. The optical limiting threshold of the QDs varies from 0.35 GW/cm2 to 0.57 GW/cm2 which makes CdSe QDs a promising candidate for reverse-saturable absorption based devices at high laser intensities such as optical limiters.

Molecularly Imprinted Sensor for Ascorbic Acid Based on Gold Nanoparticles and Multiwalled Carbon Nanotubes

2020 ◽  
Vol 16 (7) ◽  
pp. 905-913
Author(s):  
Youyuan Peng ◽  
Qingshan Miao
Keyword(s):  
Carbon Nanotubes ◽  
Gold Nanoparticles ◽  
Ascorbic Acid ◽  
Multiwalled Carbon Nanotubes ◽  
Ph Value ◽  
Biological Fluids ◽  
Water Soluble ◽  
Multiwalled Carbon ◽  
Experimental Conditions ◽  
Molecularly Imprinted

Background: L-Ascorbic acid (AA) is a kind of water soluble vitamin, which is mainly present in fruits, vegetables and biological fluids. As a low cost antioxidant and effective scavenger of free radicals, AA may help to prevent diseases such as cancer and Parkinson’s disease. Owing to its role in the biological metabolism, AA has also been utilized for the therapy of mental illness, common cold and for improving the immunity. Therefore, it is very necessary and urgent to develop a simple, rapid and selective strategy for the detection of AA in various samples. Methods: The molecularly imprinted poly(o-phenylenediamine) (PoPD) film was prepared for the analysis of L-ascorbic acid (AA) on gold nanoparticles (AuNPs) - multiwalled carbon nanotubes (MWCNTs) modified glass carbon electrode (GCE) by electropolymerization of o-phenylenediamine (oPD) and AA. Experimental parameters including pH value of running buffer and scan rates were optimized. Scanning electron microscope (SEM), fourier-transform infrared (FTIR) spectra, cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were utilized for the characterization of the imprinted polymer film. Results: Under the selected experimental conditions, the DPV peak currents of AA exhibit two distinct linear responses ranging from 0.01 to 2 μmol L-1 and 2 to 100 μmol L-1 towards the concentrations of AA, and the detection limit was 2 nmol L-1 (S/N=3). Conclusion: The proposed electrochemical sensor possesses excellent selectivity for AA, along with good reproducibility and stability. The results obtained from the analysis of AA in real samples demonstrated the applicability of the proposed sensor to practical analysis.

Sign in / Sign up

Export Citation Format

Share Document