The principal objective is to create organic field-effect transistors with enhanced sensitivity and selectivity for vapors of medical and military relevance. Organic semiconductor films with covalently bound receptors will be prepared. Selective analyte access to receptors will be controlled by designed topography resulting from surface energy and thermal effects during film growth. Electrical response should be very rapid, and will be governed by electrostatics of binding events; modeling will guide design and placement of receptors. Phosphonate-, amine-, and carbonyl-functionalized analytes will interact with hydrogen-bonding and organometallic receptors in transistor semiconductors to alter device current-voltage relationships. Preliminary results since submission demonstrate transistor sensitivity to phosphonate, and phosphonate binding to an organometallic receptor. Current stability and reproducibility have also been greatly improved over prior published work.
This is the first time that electrostatic and topographic features are being designed synergistically into organic semiconductors for detection of specific analytes. New chemistry, process sequences, and organic solid state materials will be developed. Devices will be integrated with complete sensor systems in collaboration with JHU Applied Physics Laboratory, leading to a robust technology. The investigation will form the body of at least one graduate student thesis. The sensing experiments will also be incorporated into a PI-directed undergraduate laboratory course, "Electronic Properties of Materials", in which technology enhancements and research connections are being added with JHU support. Ultimately, he will meet the societal need to sense environmental vapors indicating medical conditions, security threats, and industrial plant status, over large areas and at low cost.
