Active Assembly of CsPbBr₃ Nanorods into Microcolumns by Electric Field in Nonpolar Solvent

High-precision, controllable, mass-producible assembly of nanoparticles into complex structures or devices holds immense importance in the application across various fields but it remains challenging. Here a highly controllable and reversible active assembly of colloidal CsPbBr₃ nanorods, driven by an external electric field is achieved. This approach enables the nanorods dynamically orient themselves, assemble into chains, aggregate into columns, and eventually form an ordered column array, with the electric field intensity varying from 0 to 50 V µm^-1 at 100 kHz. The nanorods inside the columns align parallel to the electric field, leading to a well-ordered structure. With the analysis of the interactions among the nanorods, a quantitative interpretation of the assembly is proposed. Monte Carlo calculation is also introduced to simulate the assembly process and the results prove to be in great agreement with the experimental observations. This electric field-driven assembly presents an exciting opportunity to pave the way for next-generation sensors and photonic devices based on well-developed colloidal nanoparticles.