Surface Derivatization of Nanocrystalline CdSe Semiconductors

1996 ◽  
Vol 452 ◽  
Author(s):  
J.-K. Lee ◽  
M. Kuno ◽  
M. G. Bawendi
Keyword(s):  
Quantum Dots ◽  
Thermal Gravimetric Analysis ◽  
Ligand Exchange ◽  
Proton Nmr ◽  
Trioctylphosphine Oxide ◽  
Cdse Quantum Dots ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Exchange Reactions

AbstractCdSe quantum dots (QDs) with several different ligands were prepared by ligand exchange reactions of trioctylphosphine oxide (TOPO)/trioctylphosphine selenide (TOPSe) passivated QDs with an excess of new ligands, such as pyridine, 4-picoline, thiophenol, 4-(trifluoromethyl)-thiophenol, and tris(2-ethylhexyl)phosphate. We find that 85–90% of ligands passivating the surface of the QDs are the newly introduced capping species and 10–15% are native TOPO/TOPSe ligands, reflecting the incomplete exchange of the QD surface. Thermal gravimetric analysis (TGA) and quantitative proton NMR measurements show that on average only 30% of surface cadmium atoms are passivated by TOPO/TOPSe. Approximately 1/3 of these native ligands occupy sites too strongly bound to be replaced by ligand exchange reactions.

Thermal gravimetric analysis of in-situ crosslinked nanocellulose whiskers • poly(methyl vinyl ether-co-maleic acid) • polyethylene glycol

TAPPI Journal ◽  
2011 ◽  
Vol 10 (4) ◽  
pp. 29-33
Author(s):  
LEE A. GOETZ ◽  
AJI P. MATHEW ◽  
KRISTIINA OKSMAN ◽  
ARTHUR J. RAGAUSKAS
Keyword(s):  
Thermal Stability ◽  
Polyethylene Glycol ◽  
Vinyl Ether ◽  
Thermal Gravimetric Analysis ◽  
Maleic Acid ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Methyl Vinyl ◽  
Methyl Vinyl Ether

The thermal stability and decomposition of in-situ crosslinked nanocellulose whiskers – poly(methyl vinyl ether-co-maleic acid) – polyethylene glycol formulations (PMVEMA-PEG), (25%, 50%, and 75% whiskers) – were investigated using thermal gravimetric analysis (TGA) methods. The thermal degradation behavior of the films varied according to the percent cellulose whiskers in each formulation. The presence of cellulose whiskers increased the thermal stability of the PMVEMA-PEG matrix.

The in situ ligand exchange linker-assisted assembly of oil-soluble CdSe quantum dots to TiO2 films

2019 ◽  
Vol 475 ◽  
pp. 813-819 ◽  
Author(s):  
Di Zhang ◽  
Pin Ma ◽  
Shuo Wang ◽  
Mingpeng Xia ◽  
Sidong Zhang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Ligand Exchange ◽  
Cdse Quantum Dots ◽  
Tio2 Films

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.

Characterization of the electrocatalytic activity of carbon-supported platinum-based catalysts by thermal gravimetric analysis

2015 ◽  
Vol 25 (6) ◽  
pp. 468-469 ◽  
Author(s):  
Igor N. Leontyev ◽  
Daria V. Leontyeva ◽  
Alexandra B. Kuriganova ◽  
Yurii V. Popov ◽  
Olga A. Maslova ◽  
...  
Keyword(s):  
Thermal Gravimetric Analysis ◽  
Electrocatalytic Activity ◽  
Gravimetric Analysis ◽  
Thermal Gravimetric ◽  
Supported Platinum
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