Self-regenerating photocatalytic sensor based on dielectrophoretically assembled TiO2 nanowires for chemical vapor sensing
| Autor: | Kuo Chu Hwang, Shengqin Wang, Chien-Chong Hong, Wei-Han Wang, Zi-Xiang Lin, Chien Lin Kuo |
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| Rok vydání: | 2014 |
| Předmět: |
Materials science
Fabrication Microfluidics Metals and Alloys Nanowire Nanotechnology Dielectrophoresis Condensed Matter Physics Electrospinning Surfaces Coatings and Films Electronic Optical and Magnetic Materials Volumetric flow rate Electrode Materials Chemistry Photocatalysis Electrical and Electronic Engineering Instrumentation |
| Zdroj: | Sensors and Actuators B: Chemical. 194:1-9 |
| ISSN: | 0925-4005 |
| DOI: | 10.1016/j.snb.2013.12.042 |
| Popis: | In this paper we reported a new method to fabricate TiO 2 based chemical vapor sensor fabricated by dielectrophoretically assembling TiO 2 nanowires. Although TiO 2 based chemical sensors were previously reported, they were usually fabricated by the bottom-up methods, which involve tedious processes and cannot be scaled-up. In the current paper, we presented a top-down approach in the fabrication of TiO 2 nanowire based sensors. The TiO 2 nanowires were initially synthesized and subsequently directly assembled between two co-planar electrodes by dielectrophoresis in microfluidic devices. We used two different methods, ethylene glycol-mediated hydrolysis and high-voltage electrospinning, to synthesize TiO 2 nanowires with varied diameters and lengths. By incorporating a laminar flow field with AC electric fields, the control of the density of assembled TiO 2 nanowires was achieved adjusting AC frequencies and flow rates, which rendered this method repeatable and scalable for the fabrication of TiO 2 nanowire based devices. The sensing performances of chemical sensors based on the two kinds of TiO 2 nanowires were tested and compared. In the sensing experiments UV light was applied to activate the surface of TiO 2 nanowires, allowing them to be operated at room temperature. The results showed that the sensitivity of the self-regenerating chemical sensor based on TiO 2 nanowires synthesized by electrospinning exhibited 4.37 times higher than that of the nanowires prepared by the glycol-mediated hydrolysis method. The chemical sensor based on electrospun TiO 2 nanowires showed high sensitivity, fast response (less than 60 s) and fast recovery (less than 60 s) to vapor pollutants including NH 3 , acetone, and ethanol. |
| Databáze: | OpenAIRE |
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