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4246733 
Journal Article 
A dynamic equilibrium method for the SnO2-based ozone sensors using UV-LED continuous irradiation 
Jeng, CC; Chong, PJH; Chiu, CC; Jiang, GuoJ; Lin, HJu; Wu, RenJ; Wu, CH 
2014 
1 
Sensors and Actuators B: Chemical
ISSN: 0925-4005
EISSN: 1873-3077 
195 
702-706 
WOS:000332417600092 
We report the sensing characteristics of SnO2 thin-film gas sensors operated under room temperature. The sensor was continuously irradiated during sensing with ultraviolet (UV) light from a single 370-nm UV light-emitting diode (LED). The saturation resistance and sensitivity of the developed SnO2 sensor were observed to depend on the LED power. The SnO2 films produced a good response to ozone (O-3), and this response showed good reproducibility under a dynamic O-3 concentration of 5-14 ppm, and under a stable concentration. The time constant of absorption as a function of the trace O-3 concentration was analyzed, and the results showed a promising correlation between time constant and concentration. The humidity affects the lowest measured resistance, but not the response. We propose the presence of a dynamic equilibrium between the background conditions to explain the working mechanism of our sensor system. Crown Copyright (C) 2014 Published by Elsevier BY. All rights reserved. 
Dynamics equilibrium; Gas sensor; Ozone; Time constant; UV-LED; Room temperature sensing