Selective vapor sensors with thin-film MoS2-coated optical fibers

• Published in: Journal of vacuum science & technology. A, Vacuum, surfaces, and films Vol. 40; no. 3
• Main Authors: Motala, Michael, Beagle, Lucas K., Lynch, Jason, Moore, David C., Stevenson, Peter R., Benton, Anna, Tran, Ly D., Baldwin, Luke A., Austin, Drake, Muratore, Christopher, Jariwala, Deep, Glavin, Nicholas R.
• Format: Journal Article
• Language: English
• Published: 01-05-2022
• ISSN: 0734-2101; 1520-8559
• DOI: 10.1116/6.0001759

Effective chemical sensor devices must facilitate both the detection of analytes at ultralow concentrations and the ability to distinguish one analyte from another. Sensors built using two-dimensional nanomaterials have demonstrated record-level sensitivity toward certain chemical vapor species, but the specificity of chemical analyte detection remains lacking. To address this deficiency, this work pioneers the use of a broadband fiber-optic sensor coated with thin-film MoS2 where selectivity is achieved through observing changes in the visible spectrum transmission during exposure to different aliphatic and aromatic vapors. A significant loss in transmission across the fiber was observed near peaks in the refractive index associated with the C, B, and A excitons as well as at peaks associated with defect states. Several mechanisms for achieving selectivity are investigated, including deciphering donor/acceptor molecules, aromatic compounds, analytes with high refractive index, and intercalants such as aniline-based compounds. Moreover, the sensor device is entirely reusable and demonstrates reversible, empirical, and selective detection of aniline down to 6 ppm.