Improved Performance of Acetone Gas Sensing through Oxygen Vacancy Formation of ZnO Nanoparticles

Introduction Recently, interest in gas sensors have been increasing in different fields of not only industry and medical applications but also development of smart city and detection of indoor air pollutants. In particular, acetone is a volatile organic compound (VOC) used as a biomarker to indicate various diseases in human exhalation, or has been importantly measured as one of the indicator gases for indoor pollution measurement [1]. Unlike industrial sensors that need to detect relatively high concentration gas, the detection of acetone for biomarkers requires highly sensitive sensing materials which can react with the gas quickly. Metal oxide semiconductor (MOS) have been widely used as gas sensors because of their thermal and chemical stability and natural abundance. A lot of researches for detecting acetone gas using metal oxide semiconductor, for instance, WO 3 , SnO 2 and ZnO through diverse method and morphology control, have been studied in recent [2]. Among them, ZnO is in the spotlight for various reasons due to their facile size and structure control, gas reactive surface and appropriate band gap. Many papers associated gas sensing of ZnO were published in multiple ways as metal doping and quantum dot control [3, 4]. In this study, oxygen vacancy was produced by simple H 2 O 2 surface treatment of commercial ZnO, and the amount of oxygen vacancy by the degree of surface treatment was quantified. In addition, through evaluating acetone sensing performance according to the amount of oxygen vacancy, optimal vacancy amount showing significantly superior sensitivity was found. Chemical calculation described the reason of the outstanding response [5-8]. Further information will be discussed in detail. Method Surface oxygen vacancy is generated by a variety of H 2 O 2 treatment with 400 ˚C annealing. ZnO controlled oxygen vacancy was reacted with 10 ppm acetone at 300 – 500 ˚C, and confirm response of the material. Response of varied temperature was confirmed through three or more repeated sensor measurements, and the measurement was performed at various concentration ranging from 0.01 ppm to 10 ppm under optimized temperature conditions. And the performance was identified under various humidity conditions and long-term stability. Results and Conclusions When H 2 O 2 was treated on commercial ZnO, ZnO 2 was produced. ZnO with oxygen vacancy was formed after 400 ˚C annealing on the obtained ZnO 2 . Treatment with high concentrated H 2 O 2 results in m