2001年
Fast, reversible optical sensing of NO2 using 5,10,15,20-tetrakis[3,4-bis(2-ethylhexyloxy)phenyl]-21H,23H-porphine assemblies
JOURNAL OF MATERIALS CHEMISTRY
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- 巻
- 11
- 号
- 2
- 開始ページ
- 392
- 終了ページ
- 398
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1039/b006342h
- 出版者・発行元
- ROYAL SOC CHEMISTRY
The optical absorbance spectrum of LB film assemblies of 5,10,15,20-tetrakis[3,4-bis(2-ethylhexyloxy)phenyl]-21H,23H-porphine (EHO) is highly sensitive to low concentrations of NO2 in nitrogen. LB films prepared at much faster than conventional deposition rates (similar to 1000 mm min(-1)) yield t(50) response and recovery times of 25 s and 33 s respectively and show a sensitivity of 60% relative absorbance change (at 430 nm) for 4.4 ppm NO2. The morphology of these films is revealed using atomic force microscopy to contain isolated micron-size domains which are themselves composed of grains of several nm in diameter. This unconventional structure leads to a useful sensing material as a result of the molecular functionality of the porphyrin coupled to the enhanced surface area of the porous film assembly. The EHO film shows a gradually diminishing optical response as its temperature is increased, resulting from the shift in the adsorption-desorption equilibrium towards desorption as expected. The UV-visible spectrum recovers fully after exposure to NO2. The rate of recovery is slow at room temperature but can be accelerated dramatically with gentle heating (similar to 350 K) for a few seconds. The concentration dependence of the optical response over the range 0.8-4.4 ppm follows a Langmuir model.
- リンク情報
- ID情報
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- DOI : 10.1039/b006342h
- ISSN : 0959-9428
- Web of Science ID : WOS:000167139700029