Surface Chemistry of Colloidal PbSe Nanocrystals
Surface Chemistry of Colloidal PbSe Nanocrystals
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DOI：
10.1021/ja803994m
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发表时间：
2008-11-12
影响因子：
15
通讯作者：
Hens, Zeger
中科院分区：
文献类型：
--
作者：
Moreels, Iwan;Fritzinger, Bernd;Hens, Zeger
溶液核磁共振光谱（NMR）用于识别和量化胶体PbSe纳米晶体（Q-PbSe）的有机封端。我们发现，封盖主要由紧密结合的油酸配体。只有一小部分的配体壳（相对于油酸配体的数量为0-5%）由三正辛基膦组成。因此，通过改变油酸浓度来实现合成期间Q-PbSe尺寸的调节。将核磁共振结果与电感耦合等离子体质谱相结合，建立了完整的半导体核和有机配体的Q-PbSe结构模型。纳米晶体是非化学计量的，其表面由铅原子组成。表面硒原子的不存在与油酸配体壳一致。在环境条件下储存的Q-PbSe悬浮液上的NMR结果表明，氧化导致油酸配体和表面Pb原子的损失，形成溶解的油酸铅。
Solution nuclear magnetic resonance spectroscopy (NMR) is used to identify and quantify the organic capping of colloidal PbSe nanocrystals (Q-PbSe). We find that the capping consists primarily of tightly bound oleic acid ligands. Only a minor part of the ligand shell (0-5% with respect to the number of oleic acid ligands) is composed of tri-n-octylphosphine. As a result, tuning of the Q-PbSe size during synthesis is achieved by varying the oleic acid concentration. By combining the NMR results with inductively coupled plasma mass spectrometry, a complete Q-PbSe structural model of semiconductor core and organic ligands is constructed. The nanocrystals are nonstoichiometric, with a surface that is composed of lead atoms. The absence of surface selenium atoms is in accordance with an oleic acid ligand shell. NMR results on a Q-PbSe suspension, stored under ambient conditions, suggest that oxidation leads to the loss of oleic acid ligands and surface Pb atoms, forming dissolved lead oleate.