Nanostructured conductors (for example: gold, silver) interact with electromagnetic waves in fascinating and potentially useful ways; the scientific domain studying this is called plasmonics. Progress in the fabrication of nanomaterials gives access to structures with tailored plasmonic properties. Placing light-absorbing and -emitting molecules near such structures can result in enhancement of specfic photonic properties, enabling more sensitive detection, brighter light emission or increased harvesting of luminous energy, although it can be tricky to achieve this in practice.
Nanoscale structures combining plasmonic materials and molecules can be dispersed in liquid solution. Illustrative are the vivid colours exhibited by solutions of gold and silver nanoparticles of different shapes and sizes. The nanostructures are floating freely in the isotropic liquid environment at low optical densities, and we can precisely measure their interaction with light. Moreover, the liquid (often: water) leads to physical and chemical dynamics (Brownian motion, chemical change) that can be challenging to comprehend, but also offer new opportunities for designing chemical and biological sensors.
We develop and use combinations of optical spectroscopic, videomicroscopic, microfluidic and numerical methods to study, control and exploit molecularly-coated nanoparticles in solution.