Hypothesis: Due to their unique quantum yield and photostability performances, quantum nanoplatelets are very promising building blocks for future generations of display applications. The directed assembly of such colloidal nano-objects in the shape of micropixels is thus the next mandatory step to reach this goal. Selectively trapping them on electrostatically charged patterns by nanoxerography could be a versatile and appealing strategy but requires a full understanding of assembly mechanisms in order to make the most of their integration.

Experiments: We propose an experimental platform based on a smart resealable microfluidic chip coupled to an inverted optical fluorescence microscope and a high-speed camera for in situ access of such assembly mechanisms, using CdSe/CdZnS quantum nanoplatelets as model nano-objects. The global photoluminescence signal of nanoplatelet assembly on surfaces is thus recorded in real time and data extracted after image processing.

Findings: The coupling of experimental results and numerical simulation evidences the main role of advection at the origin of this directed nanoparticle trapping. Deep understanding of the involved kinetics and tuning of experimental parameters allow to make high resolution 3D quantum nanoplatelets based micro-pixels with a fine control of their lateral and vertical dimensions.