Marino Emanuele, Vasilyev Oleg A, Kluft Bas B, Stroink Milo J B, Kondrat Svyatoslav, Schall Peter
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Nanoscale Horiz. 2021 Sep 1;6(9):751-758. doi: 10.1039/d0nh00670j. Epub 2021 Jul 16.
Nanocrystal assembly represents the key fabrication step to develop next-generation optoelectronic devices with properties defined from the bottom-up. Despite numerous efforts, our limited understanding of nanoscale interactions has so far delayed the establishment of assembly conditions leading to reproducible superstructure morphologies, therefore hampering integration with large-scale, industrial processes. In this work, we demonstrate the deposition of a layer of semiconductor nanocrystals on a flat and unpatterned silicon substrate as mediated by the interplay of critical Casimir attraction and electrostatic repulsion. We show experimentally and rationalize with Monte Carlo and molecular dynamics simulations how this assembly process can be biased towards the formation of 2D layers or 3D islands and how the morphology of the deposited superstructure can be tuned from crystalline to amorphous. Our findings demonstrate the potential of the critical Casimir interaction to direct the growth of future artificial solids based on nanocrystals as the ultimate building blocks.
纳米晶体组装是开发具有自下而上定义特性的下一代光电器件的关键制造步骤。尽管付出了诸多努力，但目前我们对纳米级相互作用的理解有限，这延缓了能够产生可重复超结构形态的组装条件的建立，从而阻碍了与大规模工业流程的整合。在这项工作中，我们展示了在临界卡西米尔吸引力和静电排斥力的相互作用介导下，在平坦且无图案的硅衬底上沉积一层半导体纳米晶体。我们通过实验表明，并通过蒙特卡罗模拟和分子动力学模拟进行合理化分析，该组装过程如何能够偏向于形成二维层或三维岛状结构，以及如何将沉积超结构的形态从晶体调整为非晶体。我们的研究结果证明了临界卡西米尔相互作用在引导基于纳米晶体作为最终构建单元的未来人造固体生长方面的潜力。
