Structure-dependent hot-carrier extraction in gold nanoprism/palladium nanodomain bimetallic nanoparticles

Multimetallic nanoparticles represent an important class of material for the manipulation of nanoscale charge-carrier separation that can enable their use in various optoelectronic or catalytic applications. In this work, the optical scattering and emission properties of gold nanoprisms with surface-deposited palladium domains are studied. The size and distribution of the Pd domains are controlled by partially preventing Pd deposition at the prisms' surface with a molecular blocker. As the plasmon damping of the prisms depends on the appearance of new nonradiative decay channels due to Pd deposition, whereas the photoemission of the particles is additionally profoundly influenced by the availability of hot charge carriers, single-particle investigations are utilized to shed light on the role of the secondary metal's nanoscale surface distribution. It is found that for bimetallic particles showing similar plasmon damping properties, the hot-carrier extraction from the plasmonic core is more efficient with small Pd domains distributed over the entire particle surface compared to the case where larger, but fewer palladium domains are present. The findings can contribute to a more rational design and utilization of nanoscale heterosystems aiming at the generation and localized utilization of optically generated charge carriers.