Au−PbS Core−Shell Nanocrystals: Plasmonic Absorption Enhancement and Electrical Doping via Intra-particle Charge Transfer

We present a comparative study of optical and electronic properties for PbS nanocrystals and Au−PbS core−shell nanostructures. In Au−PbS nanostructures, we observed two nontrivial synergistic effects: (i) extinction enhancement due to coupling of surface plasmon resonance in the Au core to the excitonic states in the semiconducting PbS shell, and (ii) strong p-type electronic doping of Au−PbS nanocrystal solids that we explained by the intraparticle charge transfer between the PbS shell and the Au core.