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HL: Halbleiterphysik

HL 24: Poster II

HL 24.39: Poster

Donnerstag, 29. März 2001, 10:30–19:00, Rang S\ 3

Polyaniline-based gas and vapour sensors — •Jens Reemts, Dmitri Godovsky, and Juergen Parisi — Carl von Osszietzky Universitaet Oldenburg, Fachbereich Physik

Preparation and characterization of conductive layers of emeraldine base polyaniline, polydimethylaniline and poly-[o-tolyidine] used as a transducer for gas/organic vapour sensors was carried out. Thin polyaniline films were produced by electrochemical radical polymerization. We studied the influence of polymerization conditions as well as of the extent of doping (protonation) on the sensors sensitivity and cross selectivity towards ethyl alcohol, acetone vapours and propane gas impurities in helium in the concentration range 50-1000 ppm. The sensing layers were electropolymerized in-situ from the drop of sulfur acid solution placed in the gap between two gold electrodes separated 5-20 microns from each other. Platinum coated leucosapphire substrates were used as a heater/temperature controller. The thin 2-10 microns polymer layer conductivity change was used as a sensor signal. The signal dependencies on the impurity concentration, temperature as well as dynamics of sensor response were investigated. Basing on the obtained results we conclude, that the porosity/conductivity change, taking place as a result of protonation/deprotonation can be used to enhance the sensitivity and selectivity of polymer sensors, based on the conjugated polymers.