Decahedral nanocrystals of noble metals: Synthesis, characterization, and applications

Noble-metal nanocrystals with controlled shapes have received considerable interest owing to their unique properties and potential applications related to plasmonics, catalysis, and electronics. In particular, decahedral nanocrystals have emerged a focus of intensive research in recent years because of their unique penta-twinned structure. When employed as seeds to mediate the growth of the same or a different metal, decahedral nanocrystals have led to the production of new types of nanostructures that are otherwise difficult to generate using conventional methods. In this review, we start with a brief introduction to the unique features and properties of decahedral nanocrystals, followed by thermodynamic and kinetic analyses of their formation mechanisms. We then survey synthetic routes to the synthesis of monometallic (Ag, Au, Pd, Cu, Rh, and Pt) and alloy decahedral nanocrystals, as well as their derivatives with a core-shell, core-frame, or one-dimensional structure. At the end, we highlight the use of decahedral nanocrystals and their derivatives in photonic, catalytic, and sensing applications and conclude with perspectives on the future directions with regard to noble-metal decahedral nanocrystals.