Sensors are typically designed to effectively convert interactions occurring at gas-solid or liquid-solid interfaces, or between molecules, into measurable signals that provide information on the nature and concentration of chemical and biomolecular species present in a particular (gas or liquid) environment. This project seeks to improve the ultimate capabilities of chemical and biochemical sensors by understanding interactional effects, interfacial phenomena, and associated transduction processes, often at the nanoscale that allow detection. A wide variety of sensing principles (chemiresistive, capacitive, electrochemical, FET, mass loading, optical) can be employed in generating useful signals, but they all involve fundamental processes such as adsorption, diffusion, binding/hybridization, reaction, desorption, and charge transfer. Analytical tools including (but not limited to) x-ray and ultraviolet photoemission, scanning probe microscopies, mass spectrometry, fluorescence and other optical methods, and local electronic transport measurements are used to monitor these surface and interfacial processes. A primary objective of our research involves characterizing surface and/or molecular chemical and structural characteristics under changing environmental conditions and correlating this information to changes in measured signals. We are interested in the roles played by surface functionalization, morphological variation, and size effects (for oxides, metals, and polymers) in modifying sensitivity, as well as the utility of modulation techniques (temperature, light, voltage) for enhancing selectivity. We are also interested in effects relating to the contacting of sensor materials to device electrodes and the information content found in transient signals as conditions or modulation parameters are altered. In some cases, our mechanistic investigations benefit from experimental and theoretical studies on model sample systems consisting of crystalline samples, ordered ultrathin films, or appropriately assembled biomolecules or nanostructures (including aptamers).
Bio-interfaces; Biomolecules; Biosensors; Chemical sensors; Nanomaterials; Nanosensors; Optical methods; Photoemission spectroscopy; Scanning probe microscopy; Surfaces; Transduction;