期刊
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
卷 132, 期 29, 页码 10195-10201出版社
AMER CHEMICAL SOC
DOI: 10.1021/ja104351q
关键词
-
资金
- Belgian Science Policy Office [IAP P6/10]
- EU
- The FWO Vlaanderen [G.0064.07, G.0102.08, G.0.144.08, G.0794.10]
We use solution NMR techniques to analyze the organic/inorganic interface of CdSe quantum dots (Q-CdSe) synthesized using oleic acid as a surfactant. It is shown that the resulting Q-CdSe are stabilized by tightly bound oleic acid species that only exchange upon addition of free oleic acid. The NMR analysis points toward a two-step exchange mechanism where free ligands are initially physisorbed within the ligand shell to end up as bound, chemisorbed ligands in a second step. Importantly, we find that every ligand is involved in this exchange process. By addition of oleic acid with a deuterated carboxyl headgroup, we demonstrate that the bound ligands are oleate ions and not oleic acid molecules. This explains why a dynamic adsorption/desorption equilibrium only occurs in the presence of excess free oleic acid, which donates the required proton. Comparing the number of oleate ligands to the excess cadmium per CdSe quantum dot, we find a ratio of 2:1. This completes the picture of Q-CdSe as organic/inorganic entities where the surface excess of Cd2+ is balanced by a double amount of oleate ligands, yielding overall neutral nanoparticles.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据