Optical properties and electronic energy relaxation of metallic Au144(SR)60 nanoclusters

J Am Chem Soc. 2013 Dec 4;135(48):18222-8. doi: 10.1021/ja409998j. Epub 2013 Nov 20.


Electronic energy relaxation of Au144(SR)60(q) ligand-protected nanoclusters, where SR = SC6H13 and q = -1, 0, +1, and +2, was examined using femtosecond time-resolved transient absorption spectroscopy. The observed differential transient spectra contained three distinct components: (1) transient bleaches at 525 and 600 nm, (2) broad visible excited-state absorption (ESA), and (3) stimulated emission (SE) at 670 nm. The bleach recovery kinetics depended upon the excitation pulse energy and were thus attributed to electron-phonon coupling typical of metallic nanostructures. The prominent bleach at 525 nm was assigned to a core-localized plasmon resonance (CLPR). ESA decay kinetics were oxidation-state dependent and could be described using a metal-sphere charging model. The dynamics, emission energy, and intensity of the SE peak exhibited dielectric-dependent responses indicative of Superatom charge transfer states. On the basis of these data, the Au144(SR)60 system is the smallest-known nanocluster to exhibit quantifiable electron dynamics and optical properties characteristic of metals.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Electrons
  • Models, Molecular
  • Nanostructures / chemistry*
  • Organogold Compounds / chemistry*
  • Spectrum Analysis


  • Organogold Compounds