Kennard Jasmin J, Zelaya Solano H Jonathan, Biddulph Caleb D, Prager Ryan C, Dshemuchadse Julia
Robert F. Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, USA.
Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA.
J Chem Phys. 2024 Aug 7;161(5). doi: 10.1063/5.0219037.
Colloidal and nanoparticle self-assembly enables the creation of ordered structures with a variety of electronic and photonic functionalities. The outcomes of the self-assembly processes used to synthesize such structures, however, strongly depend on the uniformity of the individual nanoparticles. Here, we explore the simplest form of particle size dispersity-bidispersity-and its impact on the self-assembly process. We investigate the robustness of self-assembling bcc-type crystals via isotropic interaction potentials in binary systems with increasingly disparate particle sizes by determining their terminal size ratio-the most extreme size ratio at which a mixed binary bcc crystal forms. Our findings show that two-well pair potentials produce bcc crystals that are more robust with respect to particle size ratio than one-well pair potentials. This suggests that an improved self-assembly process is accomplished with a second attractive length scale encoded in the particle-particle interaction, which stabilizes the second-nearest neighbor shell. In addition, we document qualitative differences in the process of ordering and disordering: in bidisperse systems of particles interacting via one-well potentials, we observe a breakdown of order prior to demixing, while in systems interacting via two-well potentials, demixing occurs first and bcc continues to form in parts of the droplet down to low size ratios.
胶体和纳米颗粒的自组装能够创造出具有各种电子和光子功能的有序结构。然而，用于合成此类结构的自组装过程的结果在很大程度上取决于单个纳米颗粒的均匀性。在这里，我们探索颗粒尺寸分散的最简单形式——双分散性——及其对自组装过程的影响。我们通过确定自组装体心立方（bcc）型晶体在颗粒尺寸差异越来越大的二元体系中的终端尺寸比——形成混合二元bcc晶体的最极端尺寸比，研究了通过各向同性相互作用势实现的自组装bcc型晶体的稳健性。我们的研究结果表明，双阱对势产生的bcc晶体在颗粒尺寸比方面比单阱对势更稳健。这表明，通过在粒子 - 粒子相互作用中编码的第二个吸引长度尺度可以实现改进的自组装过程，该尺度稳定了次近邻壳层。此外，我们记录了有序和无序过程中的定性差异：在通过单阱势相互作用的粒子双分散体系中，我们观察到在混合之前有序性的破坏，而在通过双阱势相互作用的体系中，首先发生混合，并且在液滴的部分区域中bcc继续形成，直至低尺寸比。
