Physics and Chemistry of Nanostructures, ‡Center for Nano and Biophotonics, §Center for Molecular Modeling, and ∥NMR and Structural Analysis Unit, Ghent University , 9000 Gent, Belgium.
J Am Chem Soc. 2015 Feb 25;137(7):2495-505. doi: 10.1021/ja509941g. Epub 2015 Feb 12.
We investigate the relation between the chain length of ligands used and the size of the nanocrystals formed in the hot injection synthesis. With two different CdSe nanocrystal syntheses, we consistently find that longer chain carboxylic acids result in smaller nanocrystals with improved size dispersions. By combining a more in-depth experimental investigation with kinetic reaction simulations, we come to the conclusion that this size tuning is due to a change in the diffusion coefficient and the solubility of the solute. The relation between size tuning by the ligand chain length and the coordination of the solute by the ligands is further explored by expanding the study to amines and phosphine oxides. In line with the weak coordination of CdSe nanocrystals by amines, no influence of the chain length on the nanocrystals is found, whereas the size tuning brought about by phosphine oxides can be attributed to a solubility change. We conclude that the ligand chain length provides a practical handle to optimize the outcome of a hot injection synthesis in terms of size and size dispersion and can be used to probe the interaction between ligands and the actual solute.
我们研究了在热注射合成中使用的配体的链长与形成的纳米晶体的尺寸之间的关系。通过两种不同的 CdSe 纳米晶体合成，我们一致发现，长链羧酸导致更小的纳米晶体，具有更好的尺寸分散性。通过结合更深入的实验研究和动力学反应模拟，我们得出结论，这种尺寸调谐是由于扩散系数和溶质溶解度的变化。通过将研究扩展到胺和膦氧化物，进一步探讨了通过配体链长进行尺寸调谐与配体对溶质的配位之间的关系。与胺对 CdSe 纳米晶体的弱配位一致，我们发现配体链长对纳米晶体没有影响，而通过膦氧化物进行的尺寸调谐可以归因于溶解度的变化。我们得出结论，配体链长为优化热注射合成的结果（包括尺寸和尺寸分散性）提供了一个实际的处理方法，并可用于探测配体与实际溶质之间的相互作用。
