Colloidal Suprastructures Self-Organized from Oppositely Charged All-Inorganic Nanoparticles

The self-organization of colloidal nanoparticles into programmed suprastructures has been of great interest in a wide range of fields like nano, colloid, and polymer sciences owing to the novel multifunctional or collective physicochemical properties exhibited from the organized suprastructures [1, 2]. In addition, they are rendered as new promising materials for a wide range of application fields with their excellent colloidal stability. However, despite the recent progress in their fundamental understanding and practical applications, the self-organization of all-inorganic nanoparticles remains unexplored. The interparticle interactions among colloidal nanoparticles are usually governed by organic soft stabilizers owing to the easy introduction and controllability. However, the interactions between long-chain organic ligands are quite complex because of their multiplicities and related interdependencies [3].<br/>Herein, we present the controlled organization of oppositely charged all-inorganic nanoparticles through the electrostatic interaction and the colloidal behaviors of organized suprastructures. Three different phases of patchy, patchy bridged, and fully coated particles are classified depending on the charge states and colloidal behavior of the organized suprastructures. The phase behavior was investigated with the factors of number ratio and size ratio of oppositely charged nanoparticles. Furthermore, the phase diagram is constructed with the concentration of oppositely charged nanoparticles. Especially, the fully coated particles exhibit replicable colloidal stability through the action of nanoparticles as surface stabilizers to induce the overcharged surface state; thus, the concept of “nano-ligands” is proposed. Further experiments demonstrate that a wide range of material combinations, including semiconducting, metallic, and oxide nanoparticles is applicable for the concept of nano-ligands. The currently developed approach will enable the chemical designing of self-organized nanostructures [4].<br/>References<br/>E. V. Shevchenko, M. Ringler, A. Schwemer, D. V. Talapin, T. A. Klar, A. L. Rogach, J. Feldmann and A. P. Alivisatos, <i>J. Am. Chem. Soc.</i> 130, 3274 <b>(2008)</b>.<br/>Z. Tang, Z. Zhang, Y. Wang, S. C. Glotzer and N. A. Kotov, <i>Science</i> 314, 274 <b>(2006)</b>.<br/>C. A. Batista, R. G. Larson and N. A. Kotov, <i>Science</i> 350, 1242477 <b>(2015)</b>.<br/>D.H. Gu, J. Lee, H. W. Ban, G. Lee, M. Song, W. Choi, S. Baek, H. Jeong, S. Y. Lee, Y. Choi, J. Park, Y. I. Park and J. S. Son, <i>Chem. Mater.</i> 32, 19, 8662 <b>(2020).</b>