Title: Advanced Functional Materials as Conductometric Gas Sensors

Abstract

Gas sensors are of great importance in a wide variety of sectors, such as medical, food safety/smart packaging, energy (flammable/explosive gases) as well as environment (monitoring of air quality). Thus, nitric oxide (NO), carbon dioxide (CO₂), hydrogen (H₂), methane (CH₄), ozone (O₃), nitrogen dioxide (NO₂), are only a few of the gases that are related with these sectors and as a result there is a strong demand to be detected. A great number of materials, such as metal oxides, inorganic/organic perovskites etc. have been tested as gas sensing elements, using various gas sensing techniques such as conductometric, optical, chemoresistive etc.. Among them, conductometric metal oxide gas sensors have been extensively investigated for over 50 years, due to their high gas sensing performance, showing high and fast response, fast recovery as well as excellent repeatability and stability. However, there are still some issues that have to be addressed, such as the poor selectivity, the high operation temperature and the high input voltage, in order to be fully operated. In the current seminar, materials that were used as conductometric gas sensors, trying to overcome some of the above mentioned issues, will be presented. In specific, metal oxide semiconductors, metal oxides heterostructures as well as metal coordinated polymers were grown by various techniques and tested towards various gases, at room temperature with a low input voltage. Possible gas sensing mechanisms will be discussed.