@article{112ebbf41fae431abd78a9022ec71a57,
title = "The role of trace Ag in the synthesis of Au nanorods",
abstract = "One of the more useful syntheses of single crystalline, uniform Au nanorods from Au spherical seeds relies on the addition of trace Ag ions, yet the role that Ag+ plays has remained both elusive and controversial, due in part to lack of knowledge of how the Ag distribution in the nanorod evolves over time. In this work, we fill in this knowledge gap by correlating the spatial distribution of Ag within Au nanorods with nanorod anisotropic growth through time-course X-ray absorption spectroscopy (XAFS)-derived atomic-level elemental coordination paired with electron microscopy for nanoscale morphological analysis. Using this method, a plausible pathway for the conversion of spherical seeds into Au nanorods is proposed. Evidence shows that the nanorod anisotropic growth is directly related to the Ag surface coverage. Anisotropy is induced early in the reaction when Ag first deposits onto the nanoparticle surface, but growth occurs more isotropically as the reaction progresses and Ag diffuses into the nanorod bulk. The results of this investigation and methods employed should be extendable to many anisotropic nanoparticle syntheses that make use of trace elemental species as shape-control additives.",
author = "Moreau, {Liane M.} and Jones, {Matthew R.} and Roth, {Eric W.} and Jinsong Wu and Sumit Kewalramani and O'Brien, {Matthew N.} and Chen, {Bor Rong} and Mirkin, {Chad A.} and Bedzyk, {Michael J.}",
note = "Funding Information: S. K., C. A. M., and M. J. B. acknowledge support by the AFSOR under Award FA9550-11-1-0275. C. A. M. and L. M. M. acknowledge support from the Vannevar Bush Faculty Fellowship program sponsored by the Basic Research Office of the Assistant Secretary of Defense for Research and Engineering, and funded by the Office of Naval Research through grant N00014-15-1-0043. L. M. M. was also funded by a National Defense Science and Engineering Graduate (NDSEG) fellowship. M. R. J. and M. N. O. acknowledge support from the National Science Foundation through a graduate research fellowship. M. R. J. also acknowledges Northwestern University{\textquoteright}s International Institute for Nanotechnology for support through a Ryan Fellowship. S. K. and M. J. B. acknowledge support by Department of Energy DOE-BES through grant DE-SC0018093 for X-ray measurements and analysis. B. R. C. acknowledges support by DOE-BES through grant DE-FG02-03ER15457. This work made use of Northwestern University{\textquoteright}s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. EDX mapping was performed at the Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Coordinated Infrastructure Network (NNCI), which is supported by the National Science Foundation under NSF award no. 1541959. CNS is part of Harvard University. SAXS experiments were performed at the APS DND-CAT 5ID-D beam-line, which is supported through E. I. duPont de Nemours & Co., Northwestern University (NU), The Dow Chemical Co., and the NSF funded MRSEC at NU. XAFS and XRF experiments were performed at the APS 10BM-B beamline (MR-CAT), which is supported by DOE and the MRCAT member institutions, the APS 5BM-D beamline and the APS 20ID-B beamline (PNC-CAT). Use of the APS was supported by DOE-BES (DE-AC02-06CH11357). Publisher Copyright: {\textcopyright} 2019 The Royal Society of Chemistry.",
year = "2019",
month = jun,
day = "28",
doi = "10.1039/c9nr03246k",
language = "English (US)",
volume = "11",
pages = "11744--11754",
journal = "Nanoscale",
issn = "2040-3364",
publisher = "Royal Society of Chemistry",
number = "24",
}