The Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
The Fritz Haber Center, The Hebrew University of Jerusalem, Jerusalem 9190401, Israel.
ACS Nano. 2023 Mar 28;17(6):5852-5860. doi: 10.1021/acsnano.2c12676. Epub 2023 Mar 9.
Binary compositions of surface ligands are known to improve the colloidal stability and fluorescence quantum yield of nanocrystals (NCs), due to ligand-ligand interactions and surface organization. Herein, we follow the thermodynamics of a ligand exchange reaction of CdSe NCs with alkylthiol mixtures. The effects of ligand polarity and length difference on ligand packing were investigated using isothermal titration calorimetry (ITC). The thermodynamic signature of the formation of mixed ligand shells was observed. Correlating the experimental results with thermodynamic mixing models has allowed us to calculate the interchain interactions and to infer the final ligand shell configuration. Our findings demonstrate that, in contrast to macroscopic surfaces, the small dimensions of the NCs and the subsequent increased interfacial region between dissimilar ligands allow the formation of a myriad of clustering patterns, controlled by the interligand interactions. This work provides a fundamental understanding of the parameters determining the ligand shell structure and should help guide smart surface design toward NC-based applications.
众所周知，由于配体-配体相互作用和表面组织，表面配体的二元组合可以提高纳米晶体（NCs）的胶体稳定性和荧光量子产率。在此，我们研究了 CdSe NCs 与烷基硫醇混合物的配体交换反应的热力学。我们使用等温滴定微量热法（ITC）研究了配体极性和长度差异对配体组装的影响。观察到形成混合配体壳的热力学特征。将实验结果与热力学混合模型相关联，使我们能够计算链间相互作用，并推断最终的配体壳结构。我们的研究结果表明，与宏观表面相比，NCs 的小尺寸和随后增加的不同配体之间的界面区域允许形成由配体间相互作用控制的无数聚类模式。这项工作提供了确定配体壳结构的参数的基本理解，应该有助于指导基于 NC 的应用的智能表面设计。
