title: Capturing the crystalline phase of two-dimensional nanocrystal superlattices in action.
abstract: Critical photonic, electronic, and magnetic applications of two-dimensional nanocrystal superlattices often require nanostructures in perfect single-crystal phases with long-range order and limited defects. Here we discovered a crystalline phase with quasi-long-range positional order for two-dimensional nanocrystal superlattice domains self-assembled at the liquid-air interface during droplet evaporation, using in situ time-resolved X-ray scattering along with rigorous theories on two dimensional crystal structures. Surprisingly, it was observed that drying these superlattice domains preserved only an orientational order but not a long-range positional order, also supported by quantitative analysis of transmission electron microscopy images.
authors.affiliation: X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Jiang
authors.forename: Xiao-Min
authors.initials: XM
authors.lastname: Lin
authors.forename: Michael
authors.initials: M
authors.lastname: Sprung
authors.forename: Suresh
authors.initials: S
authors.lastname: Narayanan
authors.forename: Jin
authors.initials: J
authors.lastname: Wang
mesh_terms: D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D044367:Phase Transition; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances