Selective hydrothermal synthesis of water-soluble CdTe and CdTe/CdS colloidal quantum dots by controlling the Te/Cd molar ratio of the precursor solution

2021 ◽  
Author(s):  
Kunio Shimura ◽  
TaeGi Lee ◽  
Tatsuya Ito ◽  
DaeGwi Kim
Keyword(s):  
Quantum Dots ◽  
Hydrothermal Synthesis ◽  
Precursor Solution ◽  
Water Soluble ◽  
Colloidal Quantum Dots ◽  
Molar Ratio

scholarly journals In Situ Preparation of Amphibious ZnO Quantum Dots with Blue Fluorescence Based on Hyperbranched Polymers and their Application in Bio-Imaging

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 144 ◽  
Author(s):  
Gaiying Lei ◽  
Shu Yang ◽  
Ranran Cao ◽  
Peng Zhou ◽  
Han Peng ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Gene Transfection ◽  
Heating Time ◽  
Water Soluble ◽  
Molar Ratio ◽  
Quantum Yields ◽  
Blue Fluorescence ◽  
In Situ Preparation ◽  
Bio Imaging ◽  
Zno Quantum Dots

A new strategy for preparing amphibious ZnO quantum dots (QDs) with blue fluorescence within hyper-branched poly(ethylenimine)s (HPEI) was proposed in this paper. By changing [Zn2+]/[OH−] molar ratio and heating time, ZnO QDs with a quantum yields (QY) of 30% in ethanol were obtained. Benefiting from the amphibious property of HPEI, the ZnO/HPEI nanocomposites in ethanol could be dissolved in chloroform and water, acquiring a QY of 53%, chloroform and 11% in water. By this strategy, the ZnO/HPEI nano-composites could be applied in not only in optoelectronics, but also biomedical fields (such as bio-imaging and gene transfection). The bio-imaging application of water-soluble ZnO/HPEI nanocomposites was investigated and it was found that they could easily be endocytosed by the COS-7 cells, without transfection reagent, and they exhibited excellent biological imaging behavior.

Synthesis of CdTe and CdTe/CdS Core-Shell Quantum Dots and their Optical Properties

2011 ◽  
Vol 306-307 ◽  
pp. 1350-1353 ◽  
Author(s):  
Juan Juan Lu ◽  
Shen Guang Ge ◽  
Fu Wei Wan ◽  
Jing Hua Yu
Keyword(s):  
Quantum Dots ◽  
Thioglycolic Acid ◽  
Water Soluble ◽  
Molar Ratio ◽  
Core Shell ◽  
The Core ◽  
Cdte Qds ◽  
Quality Water ◽  
Synthesis Procedure ◽  
Pl Emission

This paper describes the synthesis of CdTe and CdTe/CdS core-shell quantum dots (QDs) in aqueous solution. The quantum dots are prepared by using thioglycolic acid (TGA) as stabilizers. The synthesis procedure is simple and controllable. Different sized CdTe QDs with tuned PL wavelengths from 550 to 640 nm was synthesized by controlling reaction time within 5 h in aqueous solutions at a temperature of 100 °C. We also investigated the influence of precursor Cd/Te molar ratio for the prepared QDs. It was showed that the core-shell CdTe/CdS QDs have larger photoluminescence (PL) emission intensity than the original CdTe QDs. The synthesized core-shell CdTe/ZnS QDs have high quality, water-soluble and will be useful in applications of biolabeling, biosensing, and imaging.

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.

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.

Relationship between Microstructure and Photoelectron Behaviors of CdTe/Ligand Self-Assembly Quantum Dots

2011 ◽  
Vol 685 ◽  
pp. 114-118
Author(s):  
Wei Yong Yang ◽  
Kui Ying Li ◽  
Sai Ling Wei ◽  
Guang Jing Song ◽  
Jan Zhang
Keyword(s):  
Quantum Dots ◽  
Grain Size ◽  
Size Effect ◽  
Self Assembly ◽  
Precursor Solution ◽  
Water Soluble ◽  
Reflux Time ◽  
The Core ◽  
Quantum Size ◽  
Cdte Qds

A water-soluble CdTe QDs capped by 3-Mercaptopropionic acid (MPA) were synthesized. The results confirmed that the grain size of the QDs was controlled by changing the reflux time of precursor solution and that the QDs possessed obviously quantum size effect. The results showed that a depletion layer CdTe1-xSx(0£x≤1) formed in between CdTe nanoparticle and ligand MPA. It is believed that two heterojunction-like structures possess quite distinct surface photovoltaic characteristic excited between the core-CdTe and the shell-CdS, and between CdTe/CdS and the ligand MPA, respectively, according to the EFISPS results of the MPA-capped CdTe QDs.

Hydrothermal Synthesis and Characterization of Mercaptopropionic Acid Modified Water-soluble CdTe Quantum Dots

2012 ◽  
Vol 33 (12) ◽  
pp. 1309-1314
Author(s):  
甘婷婷 GAN Ting-ting ◽  
张玉钧 ZHANG Yu-jun ◽  
肖雪 XIAO Xue ◽  
殷高方 YIN Gao-fang ◽  
段静波 DUAN Jing-bo ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Hydrothermal Synthesis ◽  
Water Soluble ◽  
Cdte Quantum Dots ◽  
Synthesis And Characterization ◽  
Mercaptopropionic Acid

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.

Patterned mist deposition of tri-colour CdSe/ZnS quantum dot films toward RGB LED devices

2012 ◽  
Vol 20 (2) ◽  
Author(s):  
S. Pickering ◽  
A. Kshirsagar ◽  
J. Ruzyllo ◽  
J. Xu
Keyword(s):  
Quantum Dots ◽  
Quantum Dot ◽  
Light Emitting Diodes ◽  
Light Emitting Diode ◽  
Precursor Solution ◽  
Colloidal Quantum Dots ◽  
Colloidal Solutions ◽  
Light Emitting ◽  
Mist Deposition ◽  
Viable Method

AbstractIn this experiment a technique of mist deposition was explored as a way to form patterned ultra-thin-films of CdSe/ZnS core/shell nanocrystalline quantum dots using colloidal solutions. The objective of this study was to investigate the feasibility of mist deposition as a patterning method for creating multicolour quantum dot light emitting diodes. Mist deposition was used to create three rows of quantum dot light emitting diodes on a single device with each row having a separate colour. The colours chosen were red, green and yellow with corresponding peak wavelengths of 620 nm, 558 nm, and 587 nm. The results obtained from this experiment show that it is possible to create multicolour devices on a single substrate. The peak brightnesses obtained in this experiment for the red, green, and yellow were 508 cd/m, 507 cd/m, and 665 cd/m, respectively. The similar LED brightness is important in display technologies using colloidal quantum dots in a precursor solution to ensure one colour does not dominate the emitted spectrum. Results obtained in-terms of brightness were superior to those achieved with inkjet deposition. This study has shown that mist deposition is a viable method for patterned deposition applied to quantum dot light emitting diode display technologies.

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