SFI-Strategic Research Cluster in Solar Energy Research, University of Limerick, Ireland.
Phys Chem Chem Phys. 2010 Oct 21;12(39):12430-5. doi: 10.1039/c0cp00196a. Epub 2010 Aug 16.
A multi rate kinetic model to explain the spontaneous oriented attachment of CdS nanorods in the presence of an amine is presented. The model demonstrates the reasons that elongation is restricted to a maximum of quadruple, the starting rod length for rods of a certain aspect ratio (8 × 30 nm) with no elongation occurring for rods of a shorter aspect ratio. The rate constants for all possible attachment events are determined showing that elongation by attachment occurs sequentially by single rod addition alone. Both the reaction rate and the activation energy for subsequent attachment are found to increase as the rod lengthens. The increase in reaction rate correlates with increased dipole moment of longer rods which orients the rods end to end to maximize collision events. The two components of this reaction are alignment and fusion, with the former restricting attachment of low aspect ratio rods and the latter restricting attachment to higher aspect ratio rods. The model therefore predicts an aspect ratio "window" in which oriented attachment of nanorods is energetically possible.
提出了一个多速率动力学模型来解释在胺存在下 CdS 纳米棒的自发定向附着。该模型说明了为什么伸长仅限于最大四倍，对于一定纵横比（8×30nm）的棒，起始棒长度没有伸长，而对于较短纵横比的棒则没有伸长。确定了所有可能的附着事件的速率常数，表明通过单独的单个棒添加来顺序进行伸长。发现随后的附着的反应速率和活化能都随着棒的伸长而增加。反应速率的增加与较长棒的偶极矩的增加相关，这使棒端到端取向以最大化碰撞事件。该反应的两个组成部分是对齐和融合，前者限制了低纵横比棒的附着，后者限制了对更高纵横比棒的附着。因此，该模型预测了一个在能量上可能发生纳米棒定向附着的“窗口”。
