Monolayer Self-Assembly of Monodisperse Nanocrystals at The Liquid-Air Interface
liquid-air interface self-assembly
The study of nanocrystals (NCs) self-assembly into monolayers have attracted significant interests, due to wide applications in sensors, catalysts, nanodevices and pattern transfer. Liquid-air interface self-assembly (LAISA) is a useful technique used for the monolayer fabrication. In this capstone project, a library of NCs is built for LAISA and binary superlattice study. Monodisperse iron oxide, gold and gadolinium fluoride NCs of various sizes were synthesized by modifying reported methods.9,10,20 The obtained NCs were characterized by TEM, SAXS, DLS and TGA, revealing their geometry, size and surface chemistry. The second part of this project is optimizing conditions of LAISA. Significant variables, including evaporation rate, NCs geometry, and ambient environment were isolated and studied for different building blocks. Centimeter-scale NCs monolayers with long-range order were obtained by using optimized conditions of LAISA. The binary superlattice system of spherical NCs was also investigated during this project with optimized LAISA. A 1:2 number ratio of iron oxide to gold NCs was used to fabricate binary superlattice monolayers by LAISA. The structure was revealed with TEM. However, future work is needed to investigate other size ratio and number ratio of two different kinds of NCs, and their effects on 2D structures.