Light-Directed Synthesis of Metal Nanocrystal Dimers for Scalable Precision Plasmonics

With support from the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program in the Division of Chemistry, Dr. Matthew Law at the University of California, Irvine is developing methods to link pairs of metal nanoparticles together to form dimers. The small gap between the nanoparticles can concentrate light, which could provide significant technological impact.

However, scientists still lack good syntheses for making them. Working with his students, Dr. Law is using light to protect the nanoparticle pairs as they form in a solution.

This method aims to produce dimers with higher purity, better control over structure and in larger quantities than is possible using existing methods. These fundamental studies could lead to better catalysts and chemical sensors, and new biomedical applications of these nanoparticles in the long term. The project also promotes STEM education and provides academic opportunities and enrichment to low-income students from backgrounds with historically low levels of participation in higher education.

Colloidal plasmonic metal nanocrystals (NCs) that possess strong and tunable localized surface plasmon resonances (LSPRs) in the visible and near-infrared regions of the spectrum (e.g., gold and silver NCs) are of great interest for fundamental studies of light-matter interactions. This project is developing a novel light-directed method for the one-pot, scalable synthesis of mono-disperse, tunable, and functional metal NC dimers that promises to overcome the limitations of previous approaches.

The synthesis is monitored by in situ and ex situ absorption spectroscopy and ex situ transmission electron microscopy (TEM). The resulting NC dimers are expected to have excellent structural mono-dispersity and stability, tunable and accessible hot spots, and other characteristics that make them well-suited for accelerating progress in plasmonic chemistry and physics.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.