Ultrafast Excited-State Dynamics in Shape- and Composition-Controlled Gold–Silver Bimetallic Nanostructures
| Autor: | Holly F. Zarick, Eric M. Talbert, Rizia Bardhan, Alexander A. Puretzky, Abdelaziz Boulesbaa, David B. Geohegan |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Materials science
Dephasing Analytical chemistry 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Molecular physics 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials General Energy Excited state Ultrafast laser spectroscopy Physical and Theoretical Chemistry 0210 nano-technology Absorption (electromagnetic radiation) Spectroscopy Ultrashort pulse Bimetallic strip Plasmon |
| Zdroj: | The Journal of Physical Chemistry C. 121:4540-4547 |
| ISSN: | 1932-7455 1932-7447 |
| Popis: | In this work, we have examined the ultrafast dynamics of shape- and composition-controlled bimetallic Au/Ag core/shell nanostructures with transient absorption spectroscopy (TAS) as a function of Ag layer thickness (0–15 nm) and pump excitation fluence (50–500 nJ/pulse). Our synthesis approach generated both bimetallic nanocubes and nanopyramids with distinct dipolar plasmon resonances and plasmon dephasing behavior at the resonance. Lifetimes obtained from TAS at low powers (50 nJ/pulse) demonstrated minimal dependence on the Ag layer thickness, whereas at high power (500 nJ/pulse) a rise in electron–phonon coupling lifetime (τ1) was observed with increasing Ag shell thickness for both nanocubes and nanopyramids. This is attributable to the stronger absorption of the 400 nm pump pulse with higher Ag content, which induced higher electron temperatures. The phonon–phonon scattering lifetime (τ2) also rises with increasing Ag layer, contributed both by the increasing size of the Au/Ag nanostructures as well... |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|