Tuning Au–Cu Janus Structures through Strong Ligand-Mediated Interfacial Energy Control

Bimetallic Janus structures are of great importance as their fantastic properties arise from the physical separation and the synergistic effects of the composed materials. Currently, the effective control of the Janus structure still remains a challenge compared to that of the conventional core–shell configuration and thus is highly desired. In this work, strong thiol ligands were used for tuning the interfacial energy between the Au seeds and the Cu deposit to induce the transformation of the Au–Cu core–shell to the asymmetric Janus structures. As a result of effective ligand control, a series of Au–Cu Janus structures using Au nanospheres, Au nanorods, and triangular Au nanoplates as seeds were successfully obtained. Most importantly, the Janus degree of the Au–Cu Janus structures can be readily tuned by varying the molecular structure and the amount of thiol ligands. We believe that the effective strong ligand-mediated interfacial energy control achieved in the Au–Cu system could tune bimetallic Janus structures with different metal–metal combinations, which would help in the precise control of bimetallic nanostructures. In addition, further exploration of the strong ligand control in multicomponent systems may open new doors toward the design and synthesis of sophisticated functional nanomaterials with promising properties.