Fine Tuning the Optical Properties of Single Au Nanoparticles by Plasmon-Driven Growth in Closed-Loop Control

The morphology and composition of metallic nanoparticles (NPs) determine their optical response, so finely controlling them at the single particle level is the key to achieve tailored functionalities. Here, the control of plasmon-driven growth of Au NPs is studied by live monitoring their photoluminescence emission in a closed-loop. It is found that the final emission maximum of single NPs can be tuned between 550 and 580 nm with a precision of 2-3 nm, and that the tuning is also reflected in their scattering maximum. In comparison to controlling the growth by irradiation time and/or reaction conditions, the closed-loop control delivers superior reproducibility and a three to fourfold higher precision in the final properties of the NPs.