Research Interests

Nanotechnology Enabled Chemical and Biological Sensing

Carbon nanotubes composed of a single cylindrical layer of carbon atoms, called single-walled carbon nanotubes (SWNTs), have found promising use in sensor applications because their electrical conductivity can be modified through interaction with chemical or biological species. Furthermore, the small diameter and relatively long length of SWNTs allows them to probe molecular systems on a local scale by directly "wiring into" individual or small assemblies of molecules.

In our research group we fabricate carbon nanotube field-effect transistor (NTFET) devices and explore their potential as biosensors for DNA and protein analysis. We firmly believe that NTFET technology has the potential for low-cost and portable bioanalytical platforms, which will enable hand-held field-ready devices, as opposed to current laboratory methods using labor-intensive labeling and sophisticated optical equipment.

Our research group is involved in several carbon nanotube sensor projects. To date, carbon nanotube sensors have made impressive strides in sensitivity and chemical selectivity to a diverse array of chemical species. (For more details see our recent review article Angew Chem Int Ed 2008)

Catalysis and Energy Conversion Devices

We also explore carbon nanotube potential for energy conversion devices such as fuel cells and photovoltaics. In particular, we combine solid-state electrical measurement techniques and optical spectroscopy to elucidate the trasduction mechanism between metalloporphyrins and carbon nanotubes. (See J Phys Chem C 2007)

Synthesis of carbon nanotubes and other carbon nanomaterials

We use chemical vapor deposition (CVD) with flexible gas/liquid source to synthesize carbon nanotubes. The above scanning electron microscopy (SEM) image shows a carpet of carbon nanotubes which was collected from our CVD reactor.

AFM image of nanocup decorated with gold nanoparticles

AFM image of nanocup decorated with gold nanoparticles

We have recently isolated carbon nanotube cups through incorporation of nitrogen atoms into graphitic carbon structure and subsequent mechanical treatment. The nitrogen functionalities are very useful for coupling of gold nanoparticles to the open rim of these nanocups, as can be seen in the above atomic force microscopy (AFM) image. Such nano-assemblies (12-40 nm in diameter) hold great promise for energy storage and conversion as well as for biomedical applications. (For more details see ACS Nano 2008)

Last Modified: 08-08-08