Multimetallic plasmonic nanoparticles provide a powerful opportunity to introduce functionality that is not intrinsic to noble metals. While noble-metal mixing with high activity catalytic metals is well known, relatively few studies focus on the post-transition metals that exhibit robust UV light absorption. A systematic study of noble metal-post-transition multimetallics, and the importance of intermetallic phases, remains unexplored. Here, we describe a general demonstration of how post-transition metals can manipulate the plasmonic absorption of Au and Ag plasmonic nanoparticles. We show that Sn incorporation into Ag and Au nanoparticles enables systematic tuning of the absorption towards higher energy, depending on the total incorporation of Sn and the phase behavior. We note the unique phase phase behavior of these systems as well, where alloying leads to the formation of mixed-phase solid-solution and intermetallic nanoparticles. The impact of the coexistence of distinct alloy phase behavior on the optical properties has not been widely explored in the field of plasmonics. This general approach of alloying is not restricted to Sn, but should be extendable to Bi, Ga, and In, which we highlight with theoretical plasmonic alloy calculations. Interest in approaching the UV region for plasmonics is due to the ability to harvest higher energy photons to overcome higher activation energies for catalysis, generate hot energy carriers in photoredox pathways, harness a broader range of optical behavior coupled with distinct compositional and phase tunability, and enhance spectroscopy in the ultraviolet.

Using post-transition metals to access higher energy plasmons

ACS Spring 2022

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