Modified Phonon Confinement Model and Its Application to CdSe/CdS Core–Shell Magic-Sized Quantum Dots Synthesized in Aqueous Solution by a New Route

2013 ◽  
Vol 117 (4) ◽  
pp. 1904-1914 ◽  
Author(s):  
Anielle Christine A. Silva ◽  
Ernesto S. Freitas Neto ◽  
Sebastião W. da Silva ◽  
Paulo C. Morais ◽  
Noelio O. Dantas
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Core Shell ◽  
Phonon Confinement ◽  
Confinement Model

Synthesis of highly luminescent CdTe/ZnO core/shell quantum dots in aqueous solution

2012 ◽  
Vol 47 (8) ◽  
pp. 3770-3776 ◽  
Author(s):  
Zhimin Yuan ◽  
Qian Ma ◽  
Aiyu Zhang ◽  
Yongqiang Cao ◽  
Jie Yang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Core Shell

scholarly journals Quantum Confinement Effect and Photoenhancement of Photoluminescence of PbS and PbS/MnS Quantum Dots

2020 ◽  
Vol 10 (18) ◽  
pp. 6282
Author(s):  
Muhammad Safwan Zaini ◽  
Josephine Ying Chyi Liew ◽  
Shahrul Ainliah Alang Ahmad ◽  
Abdul Rahman Mohmad ◽  
Mazliana Ahmad Kamarudin
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Quantum Confinement ◽  
Shell Thickness ◽  
Quantum Confinement Effect ◽  
Band Gap Energy ◽  
Confinement Effect ◽  
Core Shell ◽  
Lead Sulphide ◽  
Peak Energy

The quantum confinement effect and photoenhancement of photoluminescence (PL) of lead sulphide (PbS) quantum dots (QDs) and lead sulphide/manganese sulphide (PbS/MnS) core shell QDs capped with thiol ligands in aqueous solution were investigated. From PL results, the presence of MnS shells gives a strong confinement effect which translates to higher emission energy in PbS/MnS core shell QDs. Increasing MnS shell thickness from 0.3 to 1.5 monolayers (ML) causes a blueshift of PL peak energies as the charge carriers concentrated in the PbS core region. Enhancement of the PL intensity of colloidal PbS and PbS/MnS core shell QDs has been observed when the samples are illuminated above the band gap energy, under continuous irradiation for 40 min. Luminescence from PbS QDs and PbS/MnS core shell QDs can be strongly influenced by the interaction of water molecules and oxygen present in aqueous solution adsorbed on the QD surface. However, PbS/MnS core shell QDs with a shell thickness of 1.5 ML did not show a PL peak energy stability as it was redshifted after 25 min, probably due to wider size distribution of the QDs.

Photoluminescence quenching of CdTe/CdS core-shell quantum dots in aqueous solution by ZnO nanocrystals

2011 ◽  
Vol 131 (7) ◽  
pp. 1536-1540 ◽  
Author(s):  
Aimin Shi ◽  
Jianhui Sun ◽  
Qinghui Zeng ◽  
Cong Shao ◽  
Zaicheng Sun ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Core Shell ◽  
Photoluminescence Quenching ◽  
Zno Nanocrystals

scholarly journals A turn-on fluorescent sensor based on coffee-grounds carbon dots for the detection of sodium cyclamate

2021 ◽  
Author(s):  
Junzhe Chen ◽  
Haiying Du ◽  
Yifeng Xu ◽  
Boyu Ma ◽  
Zhihong Zheng ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Shell Structure ◽  
Sulfamic Acid ◽  
Carbon Quantum Dots ◽  
Core Shell ◽  
Hydroxyl Groups ◽  
Coffee Grounds ◽  
Core Shell Structure ◽  
Sodium Cyclamate

Abstract Carbon quantum dots (CQDs) were synthesized by coffee-grounds as carbon source under hydrothermal carbonization treatment for the first time. The obtained CQDs showed a strong emission at the wavelength of 460 nm, with an optimum excitation of 370 nm, and enrichment of the surface functional groups(-OH, -NH2). Sodium cyclamate in an aqueous solution and the CQDs could form a core-shell structure by hydrogen-bonding and van der waals bonding to enhance the fluorescent emission. Cyclohexyl sulfamate forms cyclohexyl sulfamate in an aqueous solution and then undergoes dehydration and condensation with the hydroxyl groups on the carbon quantum dots, and finally sodium cyclamate forms a core-shell structure around the carbon quantum dots.环己基氨基磺酸盐在水溶液中形成环己基氨基磺酸盐，然后与碳量子点上的羟基进行脱水和缩合，最后环甜酸钠在碳量子点周围形成核-壳结构。Cyclohexyl sulfamate form a cyclohexyl sulfamic acid in an aqueous solution followed by dehydration condensation with hydroxyl groups on the carbon quantum dots, cyclamate final core-shell structure is formed in the peripheral carbon quantum dot,

Facile and green synthesis of core–shell ZnSe/ZnS quantum dots in aqueous solution

2018 ◽  
Vol 29 (19) ◽  
pp. 16805-16814 ◽  
Author(s):  
S. L. Zhang ◽  
C. F. Lin ◽  
Y. L. Weng ◽  
L. C. He ◽  
T. L. Guo ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Green Synthesis ◽  
Core Shell

Enhanced Optical Properties of Core/Shell/Shell CdTe/CdS/ZnO Quantum Dots Prepared in Aqueous Solution

2009 ◽  
Vol 113 (45) ◽  
pp. 19458-19467 ◽  
Author(s):  
Fadi Aldeek ◽  
Lavinia Balan ◽  
Ghouti Medjahdi ◽  
Thibault Roques-Carmes ◽  
Jean-Pierre Malval ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Optical Properties ◽  
Core Shell ◽  
Zno Quantum Dots

Aqueous Synthesis of Highly Luminescent CdTe/CdS/ZnS Core-Shell-Shell Quantum Dots with Biocompatibility

2011 ◽  
Vol 287-290 ◽  
pp. 348-351
Author(s):  
Huai Qing Huang ◽  
Jin Ling Liu ◽  
Bao Fu Han ◽  
Shu Kun Xu
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Cell Imaging ◽  
The Other ◽  
Core Shell ◽  
Aqueous Synthesis ◽  
Fluorescent Intensity ◽  
Synthesis Time ◽  
Cds Qds ◽  
Hydrothermal Methods

CdTe/CdS/ZnS core-shell-shell (CSS) quantum dots (QDs) were synthesized in aqueous solution via water-bathing combined hydrothermal method using L-cysteine (L-Cys) as a stabilizer. This method possesses both the advantages of water-bathing and hydrothermal methods, and thus can prepare CSS QDs with markedly reduced synthesis time than previously reported methods. The as-prepared QDs display a higher fluorescent intensity than bare CdTe or CdTe/CdS. After co-cultured with yeast at different growth phase, the as-prepared L-Cys capped CdTe/CdS/ZnS QDs showed much less toxicity than the other CdTe or CdTe/CdS QDs. Our results demonstrate that the CSS QD would have a promising potential in fields of bio-labeling and cell imaging.

Synthesis and Optical Properties of Type II CdTe/CdS Core/Shell Quantum Dots in Aqueous Solution via Successive Ion Layer Adsorption and Reaction

2008 ◽  
Vol 112 (23) ◽  
pp. 8587-8593 ◽  
Author(s):  
Qinghui Zeng ◽  
Xianggui Kong ◽  
Yajuan Sun ◽  
Youlin Zhang ◽  
Langping Tu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Optical Properties ◽  
Core Shell ◽  
Type Ii ◽  
Layer Adsorption

Synthesis of Highly Luminescent Glutathione-Capped CdTe-Mn/ZnS Quantum Dots

2013 ◽  
Vol 668 ◽  
pp. 691-695
Author(s):  
Ying Fan Liu ◽  
Wei Feng He ◽  
Guo Qing Wang ◽  
Shao Ming Fang ◽  
Yu An Sun
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Environmentally Friendly ◽  
Core Shell ◽  
Sulfur Source ◽  
Synthetic Route ◽  
Reaction Conditions ◽  
Optimum Reaction ◽  
High Fluorescence

A green synthetic route is reported for quickly synthesis of highly luminescent CdTe-Mn/ZnS quantum dots (QDs) in aqueous solution. Glutathione (GSH) was used as capping reagent and thioacetamide (TAA) as sulfur source for growth of ZnS shell on the CdTe-Mn QDs. At the optimum reaction conditions, the results indicate that the GSH-capped CdTe-Mn/ZnS QDs exhibit high fluorescence QYs and the best QY is 58%. These GSH-capped core-shell QDs exhibit excellent colloidal and photostability. This method is simple and environmentally friendly.

Quenching dynamics in CdSe/ZnS core/shell quantum dots-gold nanoparticle conjugates in aqueous solution

2011 ◽  
Vol 109 (12) ◽  
pp. 124310 ◽  
Author(s):  
Li-Hua Jin ◽  
Song-Mei Li ◽  
Bong-Joon Kwon ◽  
Yong-Hoon Cho
Keyword(s):  
Aqueous Solution ◽  
Quantum Dots ◽  
Gold Nanoparticle ◽  
Core Shell
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