Shape Complementarity Modulated Self-Assembly of Nanoring and Nanosphere Hetero-nanostructures.

Shape complementarity is of paramount importance in molecular recognition, but has rarely been adopted in the self-assembly of colloidal particles, especially in the case of nanoparticles of different shapes. Here, we demonstrated a simple, yet powerful strategy for fabricating gold nanoring-based heterogeneous nanostructures (AuNR-HNs) with well-defined geometries and high yield. The assembly of various geometries of AuNR-HNs is modulated by the shape complementarity of plasmonic nanorings and nanospheres. We also present experimental evidence of dark quadrupolar ring mode excitation in AuNR-HNs through single-particle optical measurements. Our strategy will be beneficial in the study of nanoparticle assembly, photonic element interaction, and the development of plasmon-based optical devices.