Light-Driven Self-Healing of Nanoparticle-Based Metamolecules.

Metamolecules and crystals consisting of nanoscale building blocks offer rich models to study colloidal chemistry, materials science, and photonics. Herein we demonstrate the self-assembly of colloidal Ag nanoparticles into quasi-one-dimensional metamolecules with an intriguing self-healing ability in a linearly polarized optical field. By investigating the spatial stability of the metamolecules, we found that the origin of self-healing is the inhomogeneous interparticle electrodynamic interactions enhanced by the formation of unusual nanoparticle dimers, which minimize the free energy of the whole structure. The equilibrium configuration and self-healing behavior can be further tuned by modifying the electrical double layers surrounding the nanoparticles. Our results reveal a unique route to build self-healing colloidal structures assembled from simple metal nanoparticles. This approach could potentially lead to reconfigurable plasmonic devices for photonic and sensing applications.