Growth of metal–semiconductor core–multishell nanorods with optimized field confinement and nonlinear enhancement

Abstract

This paper describes a facile method for the synthesis of Au/AuAg/Ag₂S/PbS core–multishell nanorods with double trapping layers. The synthesis, in sequence, involved deposition of Ag shells onto the surfaces of Au nanorod seeds, formation of AuAg shells by a galvanic replacement reaction, and overgrowth of the Ag₂S shells and PbS shells. The resulting core–multishell nanorod possesses an air gap between the Au core and the AuAg shell. Together with the Ag₂S shell, the air gap can efficiently trap light, causing strong field confinement and nonlinear enhancement. The as-prepared Au/AuAg/Ag₂S/PbS core–multishell nanorods display distinct localized surface plasmon resonance and nonlinear optical properties, demonstrating an effective pathway for maneuvering the optical properties of nanocavities.