Publications by authors named "Rami A Khoury"
The growth dynamics of gold-silver core-shell (Au@Ag) nanoparticles are studied using in situ time-dependent second harmonic generation (SHG) and extinction spectroscopy to investigate the nanoparticle shell formation. The silver shell is grown by reduction of silver cations onto a 14 nm gold core using ascorbic acid in colloidal aqueous solution under varying reaction concentrations producing Au@Ag nanoparticles of final sizes ranging from 51 to 78 nm in diameter. The in situ extinction spectra show a rapid increase in intensity on the timescale of 5-6 s with blue shifting and narrowing of the plasmonic peak during the silver shell formation.
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- The study investigates the ultrafast dynamics of TiO2-Au nanocomposites, focusing on how gold nanocluster size affects electronic interactions and relaxation processes.
- The relaxation times linked to the plasmon depletion band remain unchanged with varying gold shell sizes, while electron transfer lifetimes significantly shorten as the shell size increases.
- Size-dependent periodic oscillations linked to acoustic phonons are noted, revealing that larger gold clusters result in lower frequencies but consistent damping times, which has implications for enhancing catalytic materials.