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Detection of Organic Mercaptan Vapors Using Thin Films of Alkylamine-Passivated Gold Nanocrystals

Briglin, Shawn M. and Gao, Ting and Lewis, Nathan S. (2004) Detection of Organic Mercaptan Vapors Using Thin Films of Alkylamine-Passivated Gold Nanocrystals. Langmuir, 20 (2). pp. 299-305. ISSN 0743-7463. doi:10.1021/la0351717.

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Alkylamine-capped gold nanocrystals have been used as chemically sensitive resistors for the detection of volatile organic mercaptan vapors. Thin (<1 × 10^(-4) cm) films of dodecylamine-capped, 6−7 nm diameter Au nanocrystals produced dc electrical resistances of 10 kΩ to 10 MΩ when deposited onto interdigitated Au/Cr electrodes. These chemiresistive vapor detectors displayed a reversible increase in dc electrical resistance when exposed to non-thiol-containing vapors such as water, acetone, or toluene delivered at a constant fraction (0.05) of their vapor pressure, with relative differential resistance responses to these vapors of ≈5% under such conditions. In contrast, the amine-capped Au nanocrystal films exhibited a much larger, irreversible decrease in resistance upon exposure to vapors possessing the thiol (−SH) functionality, including H_2S, CH_3SH, and propanethiol. Optical spectroscopic and transmission electron microscopy data indicated that the thiols displaced the amine caps, allowing the gold cores to move closer together and in some cases enter into contact, thereby lowering the film resistance. Consistently, the resistance of such films did not decrease upon exposure to octanethiol. For CH_3SH, the rate of resistance change under repeated experimental conditions allowed extraction of the concentration of analyte over the range 4 ppb to 1.5 ppm in air.

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Lewis, Nathan S.0000-0001-5245-0538
Additional Information:© 2004 American Chemical Society. Received July 1, 2003. In Final Form: September 17, 2003. Publication Date (Web): December 11, 2003. We acknowledge the NIH, an Army MURI, and the NSF for their generous support of this work.
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Army Research Office (ARO)UNSPECIFIED
Issue or Number:2
Record Number:CaltechAUTHORS:20170710-151028847
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Official Citation:Detection of Organic Mercaptan Vapors Using Thin Films of Alkylamine-Passivated Gold Nanocrystals. Shawn M. Briglin, Ting Gao, and Nathan S. Lewis Langmuir 2004 20 (2), 299-305 DOI: 10.1021/la0351717
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:78911
Deposited By: Tony Diaz
Deposited On:10 Jul 2017 22:48
Last Modified:15 Nov 2021 17:44

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