Thin Films Composed of Multiwalled Carbon Nanotubes, Gold Nanoparticles and Myoglobin for Humidity Detection at Room Temperature
✍ Scribed by Zhi-mei Qi; Mingdeng Wei; Itaru Honma; Haoshen Zhou
- Publisher
- John Wiley and Sons
- Year
- 2007
- Tongue
- English
- Weight
- 231 KB
- Volume
- 8
- Category
- Article
- ISSN
- 1439-4235
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✦ Synopsis
Abstract
Optically transparent and electrically conductive nanocomposite thin films consisting of multiwalled carbon nanotubes (MWCNTs), gold nanoparticles (GNPs) and myoglobin molecules that glue GNPs and MWCNTs together are fabricated for the first time on glass substrates from aqueous solution. The nanocomposite thin film is capable of varying its resistance, impedance or optical transmittance at room temperature in response to changes in ambient humidity. The conductometric sensitivity to relative humidity (RH) of the nanocomposite thin film is compared with those of the pure and Mb‐functionalized MWCNT layers. The pure MWCNT layer shows a small increase in its resistance with increasing RH due to the effect of p‐type semiconducting nanotubes present in the film. In contrast, a four times higher sensitivity to RH is observed for both the nanocomposite and Mb‐functionalized MWCNT thin films. The sensitivity enhancement is attributable to swelling of the thin films induced by water absorption in the presence of Mb molecules, which increases the inter‐nanotube spacing and thereby causes a further increase of the film resistance. A humidity change as low as ΔRH=0.3 % has been readily detected by conductometry using the nanocomposite thin film.