| Autor: |
Junker B; Institute of Physical and Theoretical Chemistry and Center for Light-Matter Interaction, Sensors & Analytics (LISA+), University of Tübingen, 72076 Tübingen, Germany., Kobald A; Institute of Physical and Theoretical Chemistry and Center for Light-Matter Interaction, Sensors & Analytics (LISA+), University of Tübingen, 72076 Tübingen, Germany., Ewald C; Institute of Physical and Theoretical Chemistry and Center for Light-Matter Interaction, Sensors & Analytics (LISA+), University of Tübingen, 72076 Tübingen, Germany., Janoschek P; Institute of Physical and Theoretical Chemistry and Center for Light-Matter Interaction, Sensors & Analytics (LISA+), University of Tübingen, 72076 Tübingen, Germany., Schalk M; Faculty of Production Engineering, University of Bremen, and Leibniz Institute for Materials Engineering IWT, 28359 Bremen, Germany., Weimar U; Institute of Physical and Theoretical Chemistry and Center for Light-Matter Interaction, Sensors & Analytics (LISA+), University of Tübingen, 72076 Tübingen, Germany., Mädler L; Faculty of Production Engineering, University of Bremen, and Leibniz Institute for Materials Engineering IWT, 28359 Bremen, Germany., Bârsan N; Institute of Physical and Theoretical Chemistry and Center for Light-Matter Interaction, Sensors & Analytics (LISA+), University of Tübingen, 72076 Tübingen, Germany. |
| Abstrakt: |
Chemoresistive gas sensors made from SnO 2 , ZnO, WO 3 , and In 2 O 3 have been prepared by flame spray pyrolysis. The sensors' response to CO and NO 2 in darkness and under illumination at different wavelengths, using commercially available LEDs, was investigated. Operation at room temperature turned out to be impractical due to the condensation of water inside the porous sensing layers and the irreversible changes it caused. Accordingly, for sensors operated at 70 °C, a characterization procedure was developed and proven to deliver consistent data. The resulting data set was so complex that usual univariate data analysis was intricate and, consequently, was investigated by correlation and principal component analysis. The results show that light of different wavelengths affects not only the resistance of each material, both under exposure to the target gases in humidity and in its absence, but also the sensor response to humidity and the target gases. It was found that each of the materials behaves differently under light exposure, and it was possible to identify conditions that need further investigations. |
