Fluctuation-Enhanced Sensing of Organic Vapors by Ink-Printed MoS2 Devices under UV Irradiation

This work presents the results of fluctuation-enhanced sensing (FES) of selected organic gases by MoS
2
sensor fabricated via a simple ink printing method. We demonstrate that low-frequency noise measured under UV irradiation (275 nm) is more sensitive to different gases than measured in the dark. The noise at 1 Hz under UV light increased 3.3, 3.5, 1.6, and 2.9 times for chloroform, tetrahydrofuran, acetonitrile, and acetone ambiances, respectively. By comparing the noise spectra collected in the dark and under UV light, we report that irradiation has a visible effect on the noise in the lowest frequency range (0.125–10 Hz), changing mainly the slope of the spectra. Thus, each organic gas produces a distinct signature by affecting the noise amplitude and the shape of the spectrum. The differences in the characteristic noise features among organic vapors are ascribed to differences in their molecular configuration and polar properties.