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

The self-organization of colloidal nanoparticles into programmed suprastructures is an important research area in various disciplines of nano, colloid, and polymer sciences. However, despite the recent advances in their fundamental understanding and practical applications, the self-organization of organic-free inorganic nanoparticles remains unexplored. Herein, we present the controlled organization of oppositely charged allinorganic nanoparticles through the electrostatic interaction and the colloidal behaviors of organized suprastructures. Depending on the charge states of the assembled suprastructures, three different phases, including patchy, patchy bridged, and fully coated particles, are identified, enabling the construction of the phase diagram with nanoparticle concentrations. Especially, the fully coated particles exhibit unexpected colloidal stability through the action of nanoparticles as surface stabilizers to induce the overcharged surface state; thus, we propose the concept of "nanoligands". It is demonstrated that this concept can be extended to a wide range of material combinations, including semiconducting, metallic, and oxide nanoparticles. The currently developed approach will enable the chemical designing of self-organized nanostructures.