In my research group, we utilize scanned probe microscopy to characterize a variety of materials on a nanometer length scale and with single molecule sensitivity. The materials we probe include metal and metal oxide nanocluster catalysts supported on titania; the interface between the polymer electrolyte membrane and the catalyst layer in hydrogen and direct methanol fuel cells; and the size, shape, and nanoscale morphology of molecular semiconductors used in light-emitting diodes and solar cells. In each case, we are interested in understanding the chemical activity and the physical properties of these systems at the most fundamental level.