The availability of electric power is crucial for the operation of remote sensors or implanted microsystems. We are developing technology to convert different forms of energy in the environment into usable electric energy. This includes biochemical energy harvesting inside the human body.
Supercapacitors are electrochemical capacitors that take advantage of the double-layer charge that forms across electrode-solution interfaces. By maximizing the internal surface area available, while minimizing the weight, it is possible to achieve very high specific capacitances. Energy storage density can be further increased by coating porous electrodes with redox active materials that store charges within their volumes.
High energy density, high power and long cycle life are all properties that are needed in portable energy sources, particularly for emerging electric vehicles, and multifunctional hand-held devices. We are investigating new materials for use in these electrochemical storage devices with the aim of dramatically improving all aspects of performance. We are also creating printed energy storage devices for use in smart packaging, RFIDs and the like.
In nanoscale optical devices, both the particle and the wave nature of light can play important roles. This creates new opportunities for engineering the optoelectronic properties, for instance the amount of light absorption in a device.
We use techniques ranging from classical, continuum modeling, to molecular dynamics, to quantum mechanical simulations using the density functional theory and first-principles techniques such as the Hartree-Fock method. We investigate the mechanical properties, electronic structure, transport characteristics and optical properties of nanodevices.
A significant challenge in research on nanostructures is the lack of sufficient control over the fabrication processes. Therefore, an important aspect of our research is the study of nanostructure fabrication processes with the goal of achieving higher levels of control and reproducibility.
Plants capture photons very efficiently. Can we learn from them in making photovoltaic devices? We are investigating the use of photosynthetic protein complexes in solar cells, with the aim of creating very low cost solar cells.
By embedding low dimensional (0D, 1D, 2D) materials such as nanowires, nanotubes and quantum dots in polymers, we want improve the conversion efficiency and extend the use of solar energy, as a viable clean energy solution. Significant improvements in photocurrent and photoabsorption of polymers doped with carbon nanotubes are promising for nanocomposite solar cells.