scholarly journals Intense Visible Luminescence in CdSe Quantum Dots by Efficiency Surface Passivation with H2O Molecules

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
Hyeoung Woo Park ◽  
Do-Hyung Kim
Keyword(s):  
Heat Treatment ◽  
Quantum Dots ◽  
Quantum Yield ◽  
Surface Passivation ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Effect Of Water ◽  
Visible Luminescence ◽  
Luminescence Efficiency

We have investigated the effect of water (H2O) cooling and heat treatment on the luminescence efficiency of core CdSe quantum dots (QDs). The photoluminescence (PL) quantum yield of the CdSe QDs was enhanced up to ~85%, and some periodic bright points were observed in wide color ranges during the heat treatment of QDs mixed with H2O. The PL enhancement of QDs could be attributed to the recovery of QDs surface traps by unreacted ligands confined within the hydrophilic H2O molecule containers.

Dependence of Luminescence Efficiency of CdSe Quantum Dots on Chemical Environments

2008 ◽  
Vol 8 (11) ◽  
pp. 5615-5623 ◽  
Author(s):  
Rajan Jose ◽  
Mitsuru Ishikawa ◽  
Velmurugan Thavasi ◽  
Yoshinobu Baba ◽  
Seeram Ramakrishna
Keyword(s):  
Quantum Dots ◽  
Cadmium Acetate ◽  
Trioctylphosphine Oxide ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Luminescence Efficiency ◽  
Cadmium Stearate

Dependence of photoluminescence (PL) efficiency (ΦPL) of CdSe quantum dots (QDs) on coordinating solvents, precursors, and dispersing solvents was investigated. The ΦPL of CdSe QDs was ∼0.05 when synthesized at 120 °C using the precursors, cadmium acetate (CdAc) and trioctylphosphine selenide (TOPSe) in trioctylphosphine (TOP). The ΦPL was increased from 0.05 to ∼0.1 when coordinating solvents, trioctylphosphine oxide (TOPO) and hexadecylamine (HDA), were added to the above reaction mixture. The ΦPL was dramatically increased from ∼0.1 to ∼0.7 when CdAc was replaced by cadmium stearate (CdSt). The ΦPL of CdSe QDs synthesized using cadmium stearate (CdSt)/TOPSe/TOP/TOPO was measured in butanol, chloroform, hexane, and toluene and found that the ΦPL is strong dispersing solvent-dependent. The DFT analysis at b3lyp/lanl2dz level on the interaction of CdSe QDs with chemical environments showed that oxygen-containing molecules interact strongly with CdSe compared to non-oxygen containing molecules and could influence the ΦPL.

scholarly journals 3-Mercaptopropionic, 4-Mercaptobenzoic, and Oleic Acid-Capped CdSe Quantum Dots: Interparticle Distance, Anchoring Groups, and Surface Passivation

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
José Augusto Lucena dos Santos ◽  
Fabio Baum ◽  
Emerson Cristofer Kohlrausch ◽  
Fabiele C. Tavares ◽  
Tatiane Pretto ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Oleic Acid ◽  
Photocatalytic Oxidation ◽  
Surface Passivation ◽  
Interparticle Distance ◽  
Molecular Size ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Tem Analysis ◽  
C Nmr

The optoelectronic properties of quantum dots are strongly controlled by the chemical nature of their surface-passivating ligands. In this work, we present the synthesis, characterization, and surface modification of CdSe quantum dots (QDs) and their application in solar cells. CdSe QDs were capped in oleic acid (OA), 3-mercaptopropionic acid (MPA), and 4-mercaptobenzoic acid (MBA). The QDs were characterized by transmission electron microscopy (TEM), UV-Vis absorption and emission spectrophotometry, thermogravimetric analyses, and 1H and 13C NMR. From TEM analysis, it has been observed that interparticle distance can be effectively controlled by the presence of different molecular size ligands. From the 1H and 13C NMR, specific types of interactions between the Cd2+ and the ligands have been observed. Although CdSe/OA presented larger interparticle distance as compared to CdSe/MPA and CdSe/MBA, the photocatalytic oxidation of the thiol groups on the surface of the MPA- and MBA-based quantum dots resulted in poor surface stabilization, ultimately resulting in poor power conversion efficiencies which were ca. 70% smaller than that of OA-based solar cell.

Optical Characteristics of CdSe Quantum Dots Depending on Growth Conditions and Surface Passivation

2008 ◽  
Vol 8 (9) ◽  
pp. 4899-4902 ◽  
Author(s):  
Soon Il Jung ◽  
Hyun Young Yeo ◽  
Ilgu Yun ◽  
Sung M. Cho ◽  
Il Ki Han ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Growth Temperature ◽  
Matrix Method ◽  
Surface Passivation ◽  
Growth Conditions ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Effective Surface ◽  
Organometallic Reagents

We investigated the effects of different growth conditions and surface passivation on the growth of CdSe quantum dots (QDs). The synthesis of CdSe QDs by pyrolysis of organometallic reagents was performed by using the hot-matrix method. In order to modify the size and quality of CdSe QDs, we controlled the growth temperature from 250 °C to 350 °C and the relative amount of trioctylphosphin (as the ligand of the Cd and Se precursors) to be injected into the coordinating solvent trioctylphosphineoxide. Moreover, an effective surface passivation of mono-disperse CdSe QDs was achieved by overcoating them with a larger band gap material, such as ZnS.

Developed one-pot synthesis of dual-color CdSe quantum dots for white light-emitting diode application

2018 ◽  
Vol 6 (12) ◽  
pp. 3089-3096 ◽  
Author(s):  
Sheng Dai ◽  
Cyuan-Bin Siao ◽  
Shu-Ru Chung ◽  
Kuan-Wen Wang ◽  
Xiaoqing Pan
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
Light Emitting Diode ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
One Pot ◽  
Synthetic Process ◽  
Light Emitting ◽  
One Pot Synthesis ◽  
Enhanced Stability

The size and fraction of red and green CdSe QDs can be controlled precisely during the synthetic process, thus manifesting remarkably enhanced stability.

Controlling the magic size of white light-emitting CdSe quantum dots

Nanoscale ◽  
2018 ◽  
Vol 10 (21) ◽  
pp. 10256-10261 ◽  
Author(s):  
Sheng Dai ◽  
Yu-Sheng Su ◽  
Shu-Ru Chung ◽  
Kuan-Wen Wang ◽  
Xiaoqing Pan
Keyword(s):  
Quantum Dots ◽  
Quantum Yield ◽  
White Light ◽  
Carbon Chain ◽  
Cdse Quantum Dots ◽  
Light Emitting

By employing a particular non-coordinating solvent and long carbon chain amine, white-light emitting CdSe quantum dots with magic sizes and enhanced quantum yield can be prepared.

Optimizing electron transfer from CdSe QDs to hydrogenase for photocatalytic H2 production

2019 ◽  
Vol 55 (39) ◽  
pp. 5579-5582 ◽  
Author(s):  
Monica L. K. Sanchez ◽  
Chang-Hao Wu ◽  
Michael W. W. Adams ◽  
R. Brian Dyer
Keyword(s):  
Quantum Dots ◽  
Electron Transfer ◽  
Reduction Potential ◽  
H2 Production ◽  
Cdse Quantum Dots ◽  
Redox Mediators ◽  
Cdse Qds ◽  
Electron Shuttles ◽  
Hydrogenase Enzyme

A series of viologen related redox mediators of varying reduction potential has been characterized and their utility as electron shuttles between CdSe quantum dots and hydrogenase enzyme has been demonstrated.

Switching-on superparamagnetism in diluted magnetic Fe(iii) doped CdSe quantum dots

CrystEngComm ◽  
2020 ◽  
Vol 22 (10) ◽  
pp. 1738-1745 ◽  
Author(s):  
Amar Nath Yadav ◽  
Jasleen K. Bindra ◽  
Narendra Jakhar ◽  
Kedar Singh
Keyword(s):  
Quantum Dots ◽  
Exchange Interaction ◽  
Cdse Quantum Dots ◽  
Cdse Qds ◽  
Ferromagnetic Exchange ◽  
Diluted Magnetic ◽  
Weak Ferromagnetic

Chemically prepared, 0.5% Fe(iii)-doped CdSe QDs exhibit superparamagnetism with weak ferromagnetic exchange interaction.

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 luminescent core–shell QDs based on noninjection synthesized CdSe QDs: observation of magic sized CdSe quantum dots

RSC Advances ◽  
2014 ◽  
Vol 4 (80) ◽  
pp. 42316-42325 ◽  
Author(s):  
Haifeng Zhou ◽  
Guangjun Zhou ◽  
Juan Zhou ◽  
Dong Xu ◽  
Xingshuang Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Core Shell ◽  
Cdse Quantum Dots ◽  
Cdse Qds
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