Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7141161 | Sensors and Actuators B: Chemical | 2018 | 7 Pages |
Abstract
We present a polymer-coated silicon microring resonator to detect volatile organic compounds (VOC) gases. Absorption of VOC gases into the polymer alters the refractive index around the microring, which enables quantification of absorbed gases as a resonance wavelength shift in the resonator. Two different polymers, hyperbranched polyesteramid and poly(2-vinyl pyridine), are tested as the absorption layers on the highly sensitive (80Â nm/RIU and 10,000 Q-factor) silicon microring resonator. The sensing responses to VOC gases are characterized by flowing four different gases: styrene, acetone, toluene, and isoprene, in a wide range of concentration (sub-ppm to 100Â ppm range). The hyperbranched polyesteramid coated sensor shows the highest sensitivity to styrene. Similarly, Poly(2-vinyl pyridine) coated device exhibits sensitive responses to styrene and acetone. From experiments with a wide range of gas concentrations, we observe that the sensors have two distinguished characteristics; linear and non-linear response with respect to gas concentration. To account for it, a dual mode sensing mechanism is proposed; Langmuir mode (doping effect) in the low concentration (<5Â ppm) and Henry mode (swelling effect) for higher concentration of gases. With the developed sensors, we have achieved successful detection of styrene and acetone as low as 100Â ppb.
Related Topics
Physical Sciences and Engineering
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Authors
Dongliang Fu, Jaehoon Chung, Qing Liu, Riazul Raziq, Jack Sheng Kee, Mi Kyoung Park, Suresh Valiyaveettil, Pyng Lee,