@article{8be0bfa29ea746018dfffdd73148f805,
title = "Confined Growth of DNA-Assembled Superlattice Films",
abstract = "We study the assembly of DNA-functionalized nanocubes under lateral confinement in microscale square trenches on a DNA-functionalized substrate. Microfocus small-angle X-ray scattering (SAXS) and scanning electron microscopy (SEM) are used to characterize the superlattices (SLs). The results indicate that nanocubes form simple-cubic SLs with square-prism morphology and a (100) out-of-plane orientation to maximize DNA bonding. In-plane, SLs align with the template, exposing their {100} side facets, and the degree of alignment depends on trench size. Interestingly, the distribution of in-plane orientations determined from SAXS and SEM do not agree, indicating that the internal and external structures of the SLs differ. To understand this discrepancy, X-ray ptychography is employed to image the internal structures of the SLs, revealing that SLs which appear to be single-crystalline in SEM may have subsurface grain boundaries, depending on trench size. SEM reveals that the SLs grow via nucleation and growth of randomly oriented domains, which then coalesce; this mechanism explains the observed dependence of alignment and defect structure on size. Interestingly, crystallization occurs via an unusual growth mode, whereby continuous SL layers grow on top of several misoriented islands. Overall, this work elucidates the effect of lateral confinement on the crystallization of DNA-functionalized nanoparticles and shows how X-ray ptychography can be used to gain insight into nanoparticle crystallization.",
keywords = "X-ray ptychography, colloidal crystal, micro confinement, small-angle X-ray scattering, thin film",
author = "Zheng, {Cindy Y.} and Yudong Yao and Junjing Deng and Soenke Seifert and Wong, {Alexa M.} and Byeongdu Lee and Mirkin, {Chad A.}",
note = "Funding Information: This material is based upon work supported by the Air Force Office of Scientific Research award FA9550-17-1-0348 and the Sherman Fairchild Foundation, Inc. C.Y.Z. acknowledges support by the U.S. Department of Energy, Office of Science, Office of Workforce Development for Teachers and Scientists, Office of Science Graduate Student Research (SCGSR) program. The SCGSR program is administered by the Oak Ridge Institute for Science and Education (ORISE) for the DOE. ORISE is managed by ORAU under contract number DE-SC0014664. A.M.W. acknowledges supported by the National Science Foundation Graduate Research Fellowship Program. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation, DOE, ORAU, or ORISE. This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility, operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. Extraordinary facility operations were supported in part by the DOE Office of Science through the National Virtual Biotechnology Laboratory, a consortium of DOE national laboratories focused on the response to COVID-19, with funding provided by the Coronavirus CARES Act. This work made use of the EPIC facility of Northwestern University{\textquoteright}s NU ANCE Center, which receives support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSFDMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN) and the State of Illinois, through the IIN. J.D. would like to thank Jeff Klug and Yi Jiang for the help in the preliminary stage of ptychography experiments. Publisher Copyright: {\textcopyright} 2022 American Chemical Society. All rights reserved.",
year = "2022",
month = mar,
day = "22",
doi = "10.1021/acsnano.2c00161",
language = "English (US)",
volume = "16",
pages = "4813--4822",
journal = "ACS nano",
issn = "1936-0851",
publisher = "American Chemical Society",
number = "3",
}