This study presents a simple process for producing resistance-based humidity sensors utilizing dopamine (DA) coated gold nano-particles (AuNPs) as the sensing material. The sensing material for typical humidity sensors are solid state metal oxides, graft-polymers or salt-doped polymers. However, these humidity sensors may suffer from low sensing response or slow time response since water molecules have to diffuse into the sensing materials to induce the electrical property changes. Alternatively, AuNPs have large surface area for water molecule absorption and can be potentially for high performance humidity sensing. Nevertheless, the surface property of AuNPs is hydrophobic and needs to be modified. In this regards, this work uses a highly hydrophilic molecule of dopamine to modify the surface of AuNP into hydrophilic to enhance the humidity sensing performance.
Highly hydrophilic bio-molecule of dopamine is physically bonded onto 4-6 nm AuNPs to enhance the humidity sensing performance. Results show that the DA coated AuNPs have nice humidity sensing responses in the measuring range of 20-90%RH. The measured resistance response shows >1500 times greater than the sensor using the same AuNPs without DA coating. The developed humidity sensor shows rapid time responses for water absorption (13 s) and desorption (30 s), respectively. Moreover, a 3-day long-term measurement at low, medium and high humidity ranges also shows the good stability of the developed sensor. The method developed in this study provides a simple and low-cost method to produce high-performance humidity sensors with DA-coated AuNPs.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0827112-111459 |
| Date | 27 August 2012 |
| Creators | Wang, Chun-Yi |
| Contributors | Che-Hsin Lin, Shin-Pon Ju, Chien-Hsiung Tsai, Lung-Ming Fu, Chia-Yen Lee |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0827112-111459 |
| Rights | unrestricted, Copyright information available at source archive |
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