The dynamics of exciton-plasmon interactions in non-epitaxial Au/CdS core/shell heteronanocrystals has been studied using ultrafast transient absorption spectroscopy. The hybrid interface of metal and semiconductor domains in these structures was designed to prevent an excessive lattice strain. As a result, the rate of carrier trapping on defect sites was found to be substantially reduced (lifetime, t ~ 300 ps) in comparison with Au/CdS heterostructures grown via a conventional, Au-salt reduction approach (t < 0.02 ps). Remarkably, it was found that the rate of CdS exciton dissociation due to trapping on defects or charge transfer across non-epitaxial Au/CdS interfaces was sufficiently slow to allow for ultrafast (< 0.7 picosecond) exciton-plasmon interactions to fully unfold before defect-related energy losses took place. It is hypothesized that unusually long lifetimes of excitons in non-epitaxial Au/CdS NCs should be attributed to the formation of an interstitial alloy layer (either Au2S or Ag2S) at the boundary of Au and CdS phases, which prevents a �backward� flow of charges into the metal domain.

Exciton-plasmon energy exchange in non-epitaxial Au/CdS core/shell nanocrystals

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.