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Title: Size-Dependent Coherent-Phonon Plasmon Modulation and Deformation Characterization in Gold Bipyramids and Nanojavelins

Localized surface plasmon resonances (LSPRs) arising from metallic nanoparticles offer an array of prospective applications that range from chemical sensing to biotherapies. Bipyramidal particles exhibit particularly narrow ensemble LSPR resonances that reflect small dispersity of size and shape but until recently were only synthetically accessible over a limited range of sizes with corresponding aspect ratios. Narrow size dispersion offers the opportunity to examine ensemble dynamical phenomena such as coherent phonons that induce periodic oscillations of the LSPR energy. Here, we characterize transient optical behavior of a large range of gold bipyramid sizes, as well as higher aspect ratio nanojavelin ensembles with specific attention to the lowest-order acoustic phonon mode of these nanoparticles. We report coherent phonon-driven oscillations of the LSPR position for particles with resonances spanning 670 to 1330 nm. Nanojavelins were shown to behave similarly to bipyramids but offer the prospect of separate control over LSPR energy and coherent phonon oscillation period. We develop a new methodology for quantitatively measuring mechanical expansion caused by photogenerated coherent phonons. Using this method, we find an elongation of approximately 1% per photon absorbed per unit cell and that particle expansion along the lowest frequency acoustic phonon mode is linearly proportional to excitationmore » fluence for the fluence range studied. These characterizations provide insight regarding means to manipulate phonon period and transient mechanical deformation.« less
Authors:
 [1] ;  [2] ;  [3] ;  [2] ;  [4] ;  [1]
  1. Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials
  2. Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry
  3. Argonne National Lab. (ANL), Argonne, IL (United States). Center for Nanoscale Materials
  4. Northwestern Univ., Evanston, IL (United States). Dept. of Chemistry; Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
ACS Photonics
Additional Journal Information:
Journal Volume: 3; Journal Issue: 5; Journal ID: ISSN 2330-4022
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; coherent acoustic phonons; gold nanoparticles; time-resolved spectroscopy
OSTI Identifier:
1306555