Synthesis of Au-CdS Core-Shell Hetero-Nanorods with Efficient Exciton-Plasmon Interactions

The synthesis of large lattice mismatch metal-semiconductor core-shell hetero-nanostructures remains challenging, and thus the corresponding optical properties are seldom discussed. Here, we report the gold-nanorod-seeded growth of Au-CdS core-shell hetero-nanorods by employing Ag(2)S as an interim layer that favors CdS shell formation through a cation-exchange process, and the subsequent CdS growth, which can form complete core-shell structures with controllable shell thickness. Exciton-plasmon interactions observed in the Au-CdS nanorods induce shell thickness-tailored and red-shifted longitudinal surface plasmon resonance and quenched CdS luminescence under ultraviolet light excitation. Furthermore, the Au-CdS nanorods demonstrate an enhanced and plasmon-governed two-photon luminescence under near-infrared pulsed laser excitation. The approach has potential for the preparation of other metal-semiconductor hetero-nanomaterials with complete core-shell structures, and these Au-CdS nanorods may open up intriguing new possibilities at the interface of optics and electronics.