Tin oxide films for nitrogen dioxide gas detection at low temperatures

Ab initio thermodynamic study of the SnO2(110) surface in an O2 and NO environment: a fundamental understanding of the gas sensing mechanism for NO and NO2

“…In particular, it is widely used as solid state chemical sensors to both oxidizing (e.g., CO 2 , NO 2 ) and reducing (CO, NO) gases [3][4][5][6][7][8][9][10][11][12]. In all these applications, the key for governing device functionality is the properties of SnO 2 surface or its interface with functional organic molecules.…”

“…NO and NO 2 gases, byproducts of running car and industry, are one of the most toxic air pollutants and the main source of acid rain [8,11]. Moreover, when one is over exposed (lower tolerance limit ∼5 ppm), it may lead to pulmonary disease and even the loss of human life in extreme cases.…”

“…There exist several experimental works demonstrating NO [6,7] as well as NO 2 [6,[8][9][10][11] sensing of SnO 2 in the form of nanocrystals and thick porous films. A significant decrease of surface resistance was observed when introducing NO gas in air, due to the injection of electrons from NO to oxide with formation of oxygen vacancies [7].…”

“…A significant decrease of surface resistance was observed when introducing NO gas in air, due to the injection of electrons from NO to oxide with formation of oxygen vacancies [7]. On the contrary, NO 2 interact with SnO 2 by trapping the free electrons both directly and indirectly through the ionosorbed surface oxygen species, increasing the potential barrier across grain boundaries and hence increasing its resistance [11]. Epifani et al, [10] emphasized the role of surface oxygen vacancies in the NO 2 sensing properties of SnO 2 nanocrystals by performing spectroscopic measurements and DFT calculations of the NO 2 /SnO 2 system.…”

Optical investigations of ZnO layers affected by some selected gases in the aspect of their application in optical gas sensors

“…Sensor structures sensitive to the selected gaseous environment ought to be characterized by a high sensitivity, a short time of response and a possibly low temperature of operation [1,2]. At present extensive investigations are under way aiming at the development of sensor structures sensitive to the given gaseous environment, based on semiconductor materials with a wide energy band gap [3], as well as on organic semiconductors [4].…”