Isothermal Titration Calorimetry Resolves Sequential Ligand Exchange and Association Reactions in Treatment of Oleate-Capped CdSe Quantum Dots with Alkylphosphonic Acid

2020 ◽  
Vol 124 (43) ◽  
pp. 23964-23975 ◽  
Author(s):  
Megan Y. Gee ◽  
Yi Shen ◽  
Andrew B. Greytak
2019 ◽  
Vol 475 ◽  
pp. 813-819 ◽  
Author(s):  
Di Zhang ◽  
Pin Ma ◽  
Shuo Wang ◽  
Mingpeng Xia ◽  
Sidong Zhang ◽  
...  

1996 ◽  
Vol 452 ◽  
Author(s):  
J.-K. Lee ◽  
M. Kuno ◽  
M. G. Bawendi

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.


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