...where electrons and photons run naked and free

Group Meetings & Contact Info

Stevenson Group Research

Materials Synthesis		Characterization Tools and Analysis		Ongoing and New Projects
CVD OF NANOCARBONS Chemical vapor deposition offers a more convenient and reproducible approach to synthesize nanocarbons without resorting to a number of wet chemical techniques that are potentially destructive to the carbon surface. The CVD approach allows us to create CNT electrodes via direct growth as well as enabling the fabrication of self-supported films.		INTEGRATED SPECTRO-ELECTROCHEMICAL SURFACE SCIENCE Spectroscopic Ellipsometry is being used to characterize the porous network of surfactant templated materials. This technique allows us to probe nanomaterials to determine very small (<10nm) structural features that current scanning probe techniques cannot assess.		NANOMATERIALS FOR CATALYSIS Oxygen reduction is an important reaction that takes place at the cathodic side of fuel cells and zinc air batteries. Our unique approach allows us to systematically tailor nanocarbon properties (composition, texture, size and shape) that make them inherently catalytic for oxygen reduction while also allowing for facile incorporation of metal catalysts. Current research is focused on synthesis of multimetalic non noble metal catalysts as a replacement for Pt.

ELECTRODEPOSITION OF MIXED METAL OXIDE FILMS One main area of research is to electrochemically prepare new materials with unique composition and structure. This synthetic approach offers advantages over conventional schemes, because it is a soft chemical process that can be controlled by simples adjustments to the system (solution pH, deposition potential, etc.) Spectroscopic and electrochemical experiments are then conducted to elucidate the deposition process comprehensively.		Our unique diffraction-based microscopy detection strategy exploits the use of micropatterned mesoporous sensor materials such as WO₃to monitor changes in the materials refractive index resulting from Li⁺ insertion.		NANOMATERIALS FOR ENERGY STORAGE Redox active metal oxides offer promise as electrodes in energy storage devices (e.g., lithium ion batteries). The efficiency of lithium insertion into metal oxide cathodes in batteries is a key process that directly determines the energy density and power density necessary for utilization as power sources for hybrid vehicles and portable electronics. Chemical and physical properties unique to domains on the nano-scale are being investigated via integrating scanning probe methodologies with optical techniques, in addition to the development of new hybrid experiments.

		HIGH ASPECT RATIO SPM PROBE DEVELOPMENT New materials, especially the nano-scale materials currently in development, require existing analytical tools to be further developed in order to fully elucidate the structural, electrical, and chemical properties of the system. By utilizing our knowledge of chemical vapor deposition chemistries, we have successfully fabricated both carbon nanotube and metal nanostructure based probes that are ideal for elucidating critical dimensions of nanoscale surface features, as well as their electrical and chemical properties.		NANOMATERIALS FOR ANALYSIS & SENSING Reliable quantification of target analytes at the ultralow levels (<1 nM) used in microscale schemes presents a challenge. One project in our group has focused upon development of a mediated, enzymatic electrochemical sensing scheme for pM-to-µM concentrations of biogenic analytes (e.g. cholesterol, histamine). This H₂O₂-based sensing scheme utilizes a reporter molecule that is only redox-active when activated by H₂O₂-peroxidase interactions that occur as a byproduct of enzymatic target analyte consumption. As such, background current contributions from the mediator are practically nonexistent, providing an extremely sensitive amperometric response.