Students joining this group will gain expertise in surface analytical methods, electrochemistry, materials science, and nanotechnology. The main instrumentation used will be scanning tunneling microscopy (STM) and atomic force microscopy (AFM). These microscopes were developed in the early 1980's and belong to the scanning probe microscopy (SPM) family. They are capable of imaging surfaces with atomic or molecular resolution, but have also been widely utilized for modifying surfaces on the nanoscale. Students joining the group will pursue research in the latter area.
Surface modification at the nanometer-scale is extremely important to the electronics industry and also relevant to the miniaturization of analytical or bioanalytical devices. Reducing the size of computers or sensors leads to many benefits such as faster measurements, increased portability, reduction of waste, minimization of cost, and ability to make measurements in highly confined spaces. Consequently, research in this area is of extreme practical importance and has led to recent studies of microfluidic systems, lab-on-a-chip devices, and molecular electronics. There are also fundamentally important questions to answer about the behavior of materials on the nanometer-scale. Electron transfer through nanometer-sized metal clusters is vastly different compared to bulk metals for example.
AFM and STM measure force and electron tunneling, respectively, between a sharp tip and surface to obtain a topographical image of that surface. In our research the tip will be used to manipulate nanometer-sized molecular entities on a surface through chemical forces. This involves working with materials such as dendrimers, metal nanoparticles, carbon nanotubes, fullerenes, polymer beads, or silica beads. The students will also be involved in functionalizing tips and surfaces by self-assembly and organic coupling reactions. AFM is an extremely sensitive instrument for measuring electrostatic, hydrogen bonding, metal-ligand interactions, and other intermolecular forces between the tip and surface. These types of interactions will be measured and used to manipulate molecular entities on the surface with the AFM tip. Manipulating metal nanoparticles on surfaces is directly relevant to electronics since these materials are possibly the future components for computers based on single electron transistors (SET). This is an area that will be intensely pursed in this lab.
Even though AFM and STM are the most important techniques for this research, other complimentary techniques like surface FTIR, quartz crystal microgravimetry (QCM), UV-vis, electron microscopy, and electrochemistry will also being utilized. Experiments conducted in this lab will cross many disciplines and give students a broad background in materials science, analytical chemistry, surface microscopy, electrochemistry, electronics, and self-assembly.
