Long-term stability and energy discharge capacity of metal oxide valve elements

1988 ◽  
Vol 3 (4) ◽  
pp. 1656-1665 ◽  
Author(s):  
P. Kirkby ◽  
C.C. Erven ◽  
O. Nigol
Chemosensors ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 41
Author(s):  
Hao Zeng ◽  
Guozhu Zhang ◽  
Kazuki Nagashima ◽  
Tsunaki Takahashi ◽  
Takuro Hosomi ◽  
...  

During the past two decades, one–dimensional (1D) metal–oxide nanowire (NW)-based molecular sensors have been witnessed as promising candidates to electrically detect volatile organic compounds (VOCs) due to their high surface to volume ratio, single crystallinity, and well-defined crystal orientations. Furthermore, these unique physical/chemical features allow the integrated sensor electronics to work with a long-term stability, ultra-low power consumption, and miniature device size, which promote the fast development of “trillion sensor electronics” for Internet of things (IoT) applications. This review gives a comprehensive overview of the recent studies and achievements in 1D metal–oxide nanowire synthesis, sensor device fabrication, sensing material functionalization, and sensing mechanisms. In addition, some critical issues that impede the practical application of the 1D metal–oxide nanowire-based sensor electronics, including selectivity, long-term stability, and low power consumption, will be highlighted. Finally, we give a prospective account of the remaining issues toward the laboratory-to-market transformation of the 1D nanostructure-based sensor electronics.


Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 610
Author(s):  
Cheonji Lee ◽  
Sunjong Oh ◽  
Seung-Chul Park ◽  
Ho-Nyun Lee ◽  
Hyun-Jong Kim ◽  
...  

Metal-oxide sensors, detect gas through the reaction of surface oxygen molecules with target gases, are promising for the detection of toxic pollutant gases, combustible gases, and organic vapors; however, their sensitivity, selectivity, and long-term stability limit practical applications. Porous structure for increasing surface area, adding catalyst, and altering the operation temperature are proposed for enhancing the sensitivity and selectivity. Although humidity can significantly affect the property and stability of the sensors, studies focusing on the long-term stability of gas sensors are scarce. To reduce the effects of humidity, 1H, 1H, 2H, 2H–perfluorooctyltriethoxysilane (PFOTS) was coated on a porous SnO2 film. The interconnected SnO2 nanowires improved the high surface area, and the PFOTS coating provided superhydrophobicity at water contact angle of 159°and perfect water vapor repellency inside E-SEM. The superhydrophobic porous morphology was maintained under relative humidity of 99% and operating temperature of 300 °C. The CO gas sensing of 5, 20, and 50 ppm were obtained with linearity at various humidity. Flame detection was also achieved with practical high humidity conditions. These results suggest the simple way for reliable sensing of nanostructured metal-oxide gas sensors with high sensitivity and long-term stability even in highly humid environments.


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