title: Multiscale periodic assembly of striped nanocrystal superlattice films on a liquid surface.
abstract: Self-assembly of nanocrystals (NCs) into periodically ordered structures on multiple length scales and over large areas is crucial to the manufacture of NC-based devices. Here, we report an unusual yet universal approach to rapidly assembling hierarchically organized NC films that display highly periodic, tunable microscale stripe patterns over square centimeter areas while preserving the local superlattice structure. Our approach is based on a drying-driven dynamic assembly process occurring on a liquid surface with the stripe pattern formed by a new type of contact-line instability. Periodic ordering of NCs is realized on microscopic and nanoscopic scales simultaneously without the need of any specialized equipment or the application of external fields. The striped NC superlattice films obtained can be readily transferred to arbitrary substrates for device fabrication. The periodic structure imparts interesting modulation and anisotropy to the properties of such striped NC assemblies. This assembly approach is applicable to NCs with a variety of compositions, sizes, and shapes, offering a robust, inexpensive route for large-scale periodic patterning of NCs.
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA. adong@lbl.gov
authors.forename: Angang
authors.initials: A
authors.lastname: Dong
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Soong Ju
authors.initials: SJ
authors.lastname: Oh
authors.forename: Weon-kyu
authors.initials: WK
authors.lastname: Koh
authors.forename: Faxian
authors.initials: F
authors.lastname: Xiu
authors.forename: Xingchen
authors.initials: X
authors.lastname: Ye
authors.forename: Dong-Kyun
authors.initials: DK
authors.lastname: Ko
authors.forename: Kang L
authors.initials: KL
authors.lastname: Wang
authors.forename: Cherie R
authors.initials: CR
authors.lastname: Kagan
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Murray
mesh_terms: D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008567:Membranes, Artificial; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D012996:Solutions; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D008567:Membranes, Artificial; D012996:Solutions