The physics of ions in liquid are directly relevant to a surprisingly wide array of research areas of current scientific and societal interest. These include nanoscience (the ‘natural’ length scale for ions), energy (fuel cells, supercapacitors), neuroscience (signal transduction, new experimental tools), and health and environment monitoring (new and better sensors).

Our research is currently divided into a number of main lines:

1.Ionic liquids:

We investigate ionic correlations, overscreening, lattice saturation, and steric effects in ionic liquids near electrode surfaces. Why do ionic liquids charge/discharge so slowly? Either due to the molecular rearrangement of the ions near the solid interface, or due to the ability of the liquid to deliver more ions to the interface from the bulk. In equivalent circuit analysis spiel, this is either the capacitive or resistive time scale, respectively. Our research is to understand these different effects.

2.Electrochemical nanofluidics:

We employ micro/nanofabrication to create liquid-filled, nanometer-scale channels and chambers in which small numbers of molecules (and even single molecules) are detected and manipulated using electrical signals. Our devices count among the most sensitive electrochemical sensors built to date. We are currently extending this technique to allow single-molecule fingerprinting in the context of DNA sequencing applications.

3.High-frequency CMOS nanocapacitor array sensors:

Massively parallel, label free biosensing platforms can in principle be realized by combining all-electrical detection with low-cost integrated circuits. We explore the physics underlying the operation of large-scale, high-density array of nanoelectrodes integrated with CMOS electronics on a single chip. This approach allows detecting and fingerprinting analytes ranging from macromolecules and inorganic nanoparticles to living cells