On the in situ 3D electrostatic directed assembly of CdSe/CdZnS colloidal quantum nanoplatelets towards display applications

• Published in: Journal of colloid and interface science Vol. 630; pp. 924 - 933
• Main Authors: Midelet, Clyde, Petit, Gaëtan, Raffy, Simon, Hallez, Yannick, Mendes Marinho, Stéphanie, Pousthomis, Marc, D'Amico, Michele, Guérin, François, Palleau, Etienne, Ressier, Laurence
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.01.2023; Elsevier
• Subjects: Chemical Sciences; Directed assembly; Displays; In situ optical characterizations; Microfluidics; Nanoxerography; Quantum nanoplatelets; Quantum nanoplatelets; Displays; In situ optical characterizations; Directed assembly; Nanoxerography; Microfluidics
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2022.10.011

[Display omitted] •Development of an experimental platform based on a smart resealable microfluidic chip coupled to an inverted optical fluorescence microscope and a high-speed camera to perform in situ monitoring of the assembly of photoluminescent nano-objects on surfaces.•Deciphering the 3D assembly mechanisms of CdSe/CdZnS colloidal quantum nanoplatelets by nanoxerography, coupling experiments with numerical simulations.•Tuning on demand the thickness of CdSe/CdZnS quantum nanoplatelet-based patterns from monolayers to multilayers.•Realization of an array of 3 µmx3 µmx60 nm CdSe/CdZnS quantum nanoplatelets based pixels on a cm2 transparent surface area towards applications in photoemissive displays. Hypothesis: Due to their unique quantum yield and photostability performances, quantum nanoplatelets are very promising building blocks for future generations of displays. The directed assembly of such colloidal nano-objects in the shape of micro-pixels 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 the 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 photoluminescence signal of the nanoplatelet patterns is thus recorded in real time during their assembly and data extracted after image processing. Findings: The coupling of experimental results and numerical simulations evidences the main role of advection at the origin of this directed nanoparticle trapping. Deep understanding of the involved mechanisms and tuning of experimental parameters allow to make high resolution quantum nanoplatelet based micro-pixels with a fine control of their lateral and vertical dimensions.