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Graphene as the active layer for gas detection
Zach, Pavel ; Prášek, Jan (referee) ; Gablech, Imrich (advisor)
The aim of this bachelor thesis is to sum up theoretical knowledge concerning gas detection by sensor with a graphene active layer. It is focused on principles and construction of selected sensors. Furthermore, this work describes values characterizing the measurement results. Both crystallographic and electrical properties of graphene are discussed as well. This thesis explains the methods of production of graphene and its derivatives and also gives a look into selected characterization methods for the study of graphene. Furthermore, this work describes the phenomena behind the sensor's ability to detect gas. At the end of this study, the results of gas measurements (NO2, NH3, H2 etc.) by a graphene transistor are interpreted.
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Chemical sensor for the quality of the protective atmosphere of packaged foods
Filipi, Denisa ; Čeppan, Michal (referee) ; Veselý, Michal (advisor)
This thesis deals with optimizing compositions to prepare thin films for the quality sensor of the protective atmosphere of packaged food. This sensor is based on the detection of oxygen ingress into a modified atmosphere food package using a colour change of the sensor. Titanium dioxide dispersion was used as semiconductor and glycerol as sacrificial electron donor. The effect of the polymer matrix on the prepared thin films's appearance and on the reduction and reoxidation rates of the films was investigated. The thickness and rheological parameters of the selected sensor mixture were characterized and the stability of the thin films under visible light was monitored. The effect of oxygen concentration on the sensor's reverse oxidation kinetics was also studied. Furthermore, the selected sensor mixture print conversion from laboratory to operational scale was carried out. The prepared sensor thin films can be reduced by UV radiation with an intensity of 0.4 mW·cm2 in 35 s, and the color response of the film is visible even at low oxygen concentrations.
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Graphene as the active layer for gas detection
Zach, Pavel ; Prášek, Jan (referee) ; Gablech, Imrich (advisor)
The aim of this bachelor thesis is to sum up theoretical knowledge concerning gas detection by sensor with a graphene active layer. It is focused on principles and construction of selected sensors. Furthermore, this work describes values characterizing the measurement results. Both crystallographic and electrical properties of graphene are discussed as well. This thesis explains the methods of production of graphene and its derivatives and also gives a look into selected characterization methods for the study of graphene. Furthermore, this work describes the phenomena behind the sensor's ability to detect gas. At the end of this study, the results of gas measurements (NO2, NH3, H2 etc.) by a graphene transistor are interpreted.
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