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Porous Silicon-Based Optical Microsensors for Volatile Organic Analytes: Effect of Surface Chemistry on Stability and Specificity

  1. Anne M. Ruminski1,
  2. Brian H. King1,
  3. Jarno Salonen2,
  4. Jay L. Snyder3,
  5. Michael J. Sailor1,*

Article first published online: 9 JUL 2010

DOI: 10.1002/adfm.201000575

Issue

Advanced Functional Materials

Advanced Functional Materials

Volume 20, Issue 17, pages 2874–2883, September 9, 2010

Additional Information

How to Cite

Ruminski, A. M., King, B. H., Salonen, J., Snyder, J. L. and Sailor, M. J. (2010), Porous Silicon-Based Optical Microsensors for Volatile Organic Analytes: Effect of Surface Chemistry on Stability and Specificity. Adv. Funct. Mater., 20: 2874–2883. doi: 10.1002/adfm.201000575

Author Information

  1. 1

    Department of Chemistry and Biochemistry, The University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093–0358 (USA)

  2. 2

    Department of Physics, University of Turku, FI-20014, Turku (Finland)

  3. 3

    National Institute of Occupational Safety and Health, NIOSH/NPPTL, Pittsburgh, PA 15236 (USA)

*Department of Chemistry and Biochemistry, The University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093–0358 (USA).

Publication History

  1. Issue published online: 8 SEP 2010
  2. Article first published online: 9 JUL 2010
  3. Manuscript Revised: 24 MAY 2010
  4. Manuscript Received: 25 MAR 2010

Funded by

  • National Institute for Occupational Safety and Health and by the National Science Foundation under. Grant Number: DMR-0806859

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Keywords:

  • porous silicon;
  • photonic crystals;
  • remote sensors;
  • chemical sensors;
  • volatile organic compounds

Abstract

Sensing of the volatile organic compounds (VOCs) isopropyl alcohol (IPA) and heptane in air using sub-millimeter porous silicon-based sensor elements is demonstrated in the concentration range 50–800 ppm. The sensor elements are prepared as one-dimensional photonic crystals (rugate filters) by programmed electrochemical etch of p++ silicon, and analyte sensing is achieved by measurement of the wavelength shift of the photonic resonance. The sensors are studied as a function of surface chemistry: ozone oxidation, thermal oxidation, hydrosilylation (1-dodecene), electrochemical methylation, reaction with dicholorodimethylsilane and thermal carbonization with acetylene. The thermally oxidized and the dichlorodimethylsilane-modified materials show the greatest stability under atmospheric conditions. Optical microsensors are prepared by attachment of the porous Si layer to the distal end of optical fibers. The acetylated porous Si microsensor displays a greater response to heptane than to IPA, whereas the other chemical modifications display a greater response to IPA than to heptane. The thermal oxide sensor displays a strong response to water vapor, while the acetylated material shows a relatively weak response. The results suggest that a combination of optical fiber sensors with different surface chemistries can be used to classify VOC analytes. Application of the miniature sensors to the detection of VOC breakthrough in a full-scale activated carbon respirator cartridge simulator is demonstrated.

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