Heterometallic Seed-Mediated Growth of Monodisperse Colloidal Copper Nanorods with Widely Tunable Plasmonic Resonances (original) (raw)
We report a heterometallic seed-mediated synthesis method for monodisperse penta-twinned Cu 2 nanorods using Au nanocrystals as seeds. Elemental analyses indicate that resultant nanorods consist predominantly of copper with a gold content typically below 3 at. %. The nanorod aspect 4 ratio can be readily adjusted from 2.8 to 13.1 by varying the molar ratio between Au seeds and Cu 5 precursor, resulting in narrow longitudinal plasmon resonances tunable from 762 to 2201 nm. 6 Studies of reaction intermediates reveal that symmetry-breaking is promoted by rapid nanoscale 7 diffusion in Au-Cu alloys and the formation of a gold-rich surface. The growth pathway features 8 co-evolving shape and composition whereby nanocrystals become progressively enriched with Cu 9 concomitant with nanorod growth. The availability of uniform colloidal Cu nanorods with widely 10 tunable aspect ratios opens new avenues toward the synthesis of derivative one-dimensional metal 11 nanostructures, and applications in surface-enhanced spectroscopy, bioimaging, electrocatalysis, 12 among others. ASSOCIATED CONTENT 1 Supporting Information. Experimental section, structural characterization of Cu NRs, FDTD 2 simulation results and studies of reaction intermediates are included. This material is available free 3 of charge via the Internet at http://pubs.acs.org.
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