Au@NiO core-shell nanoparticles as a p-type gas sensor: Novel synthesis, characterization, and their gas sensing properties with sensing mechanism
- Authors
- Majhi, Sanjit Manohar; Naik, Gautam Kumar; Lee, Hu-Jun; Song, Ho-Geun; Lee, Cheul-Ro; Lee, In-Hwan; Yu, Yeon-Tae
- Issue Date
- 1-9월-2018
- Publisher
- ELSEVIER SCIENCE SA
- Keywords
- Au@NiO; Core-shell NPs; Baseline resistance; Sensitivity; M@p-MOS
- Citation
- SENSORS AND ACTUATORS B-CHEMICAL, v.268, pp.223 - 231
- Indexed
- SCIE
SCOPUS
- Journal Title
- SENSORS AND ACTUATORS B-CHEMICAL
- Volume
- 268
- Start Page
- 223
- End Page
- 231
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/73147
- DOI
- 10.1016/j.snb.2018.04.119
- ISSN
- 0925-4005
- Abstract
- In this work, Au@NiO core-shell nanoparticles (C-S NPs) as a p-type gas sensing material was synthesized by a facile wet-chemical method, and evaluated their gas sensing properties as compared to the pristine NiO NPs gas sensors. Transmission electron microscope (TEM) results exhibited the well-dispersed formation of Au@NiO C-S NPs having the total size of 70-120 nm and NiO shells having 30-50 nm thickness. The C-S morphology as well as the overall particle sizes are unchanged even at 500 degrees C. The gas sensing result reveals that the response of Au@NiO C-S NPs gas sensor is higher than pristine NiO NPs gas sensor for 100 ppm of ethanol at 200 degrees C operating temperature. The baseline resistance in the air for Au@NiO C-S NPs sensor is lowered as compared to pristine NiO NPs, which is due to the increased number of holes as charge carriers in Au@NiO C-S NPs. The high response of Au@NiO core-shell NPs as compared to pristine NiO NPs is attributed to electronic and chemical sensitization effects of Au. In Au@NiO C-S structure, the contact between metal (Au) and semiconductor (NiO) formed a Schottky junction since Au metal acted as electron acceptor, a withdrawal of electrons from NiO by Au metal core leaved behind number of holes as charge carriers in Au@NiO C-S NPs. Therefore, the baseline resistance of Au@NiO C-S NPs greatly decreased than pristine NiO NPs, as a result the Au@NiO C-S NPs showed higher response. On the other hand, in chemical sensitization effect, Au NPs catalyzed to dissociate O-2 molecules into ionic species. This work will give some clue to the researchers for the further development of p-type based C-S NPs sensors. (c) 2018 Elsevier B.V. All rights reserved.
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