Four-Wire Impedance Spectroscopy on Planar Zeolite/Chromium Oxide Based Hydrocarbon Gas Sensors

Titelangaben

Hagen, Gunter ; Schulz, Anne ; Knörr, Matthias ; Moos, Ralf:
Four-Wire Impedance Spectroscopy on Planar Zeolite/Chromium Oxide Based Hydrocarbon Gas Sensors.
In: Sensors. Bd. 7 (2007) Heft 11 . - S. 2681-2692.
ISSN 1424-8220
DOI: https://doi.org/10.3390/s7112681

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Abstract

Impedometric zeolite hydrocarbon sensors with a chromium oxide intermediatelayer show a very promising behavior with respect to sensitivity and selectivity. Theunderlying physico-chemical mechanism is under investigation at the moment. In order toverify that the effect occurs at the electrode and that zeolite bulk properties remain almostunaffected by hydrocarbons, a special planar setup was designed, which is very close to realsensor devices. It allows for conducting four-wire impedance spectroscopy as well as two-wire impedance spectroscopy. Using this setup, it could be clearly demonstrated that thesensing effect can be ascribed to an electrode impedance. Furthermore, by combining two-and four-wire impedance measurements at only one single frequency, the interference of thevolume impedance can be suppressed and an easy signal evaluation is possible, withouttaking impedance data at different frequencies.