Characterization of a porous silicon - fluorescent polymer explosives sensor
Amplifying fluorescence technology has been employed since Dr. Timothy Swager first published its use in bioanalyte detection in 2003 (Hancock et al.), forming the basis for such successful explosives sensors as the Fido Explosives Sensor, manufactured by ICx technologies. Where Dr. Swager’s team employed flat silicon substrates and focused on enhancing the organic component of their sensor, this research employed an extensively-conjugated polymer, poly-2-methoxy-5-(2’-ethylhexyloxy)-p-phenylenevinylene (MEH-PPV) and studied the silicon substrate. Employing a materials science approach, p-type boron-doped silicon wafers were electrochemically etched with a hydrofluoric acid solution to create a porous layer with greatly increased surface area and improved optical properties. Introducing a chloroform solution of the polymer into the porous layer creates a selective explosives sensor, the mechanism of which involves quenching of the polymer photoluminescence by the analyte molecules and subsequent recovery of the initial signal by air or nitrogen flow. This dissertation describes the process by which particular combinations of parameters for the sensor were used to study the creation of the porous layer, the method of introduction of the polymer solution, some photochemistry of the polymer solution itself, and polymer additives.
Drew R Brodeur,
"Characterization of a porous silicon - fluorescent polymer explosives sensor"
Dissertations and Master's Theses (Campus Access).