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Gas sensing for dimethyl sulfoxide (DMSO) based on rotational absorption spectroscopy is demonstrated in the 220–330 GHz frequency range using a robust electronic THz-wave spectrometer. DMSO is a flammable liquid commonly used as a solvent in the food and pharmaceutical industries, materials synthesis, and manufacturing. DMSO is a hazard to human health and the work environment; hence, remote gas sensing for DMSO environmental and process monitoring is desired. Absorption measurements were carried out for pure DMSO at 297 K and 0.4 Torr (53 Pa). DMSO was shown to have a unique rotational fingerprint with a series of repeating absorption bands. The frequencies of transitions observed in the present study were found to be in good agreement with spectral simulations carried out based on rotational parameters derived in prior work. Newly, intensities of the rotational absorption lines were experimentally observed and reported for DMSO in this study. Measured intensities for major absorption lines were found in very good agreement with relative line intensities estimated by quantum mechanical calculations. The sensor developed here exhibited a detection limit of 1.3 × 1015–2.6 × 1015 DMSO molecules/cm3 per meter of absorption path length, with the potential for greater sensitivity with signal-to-noise improvements. The study illustrates the potential of all electronic THz-wave systems for miniaturized remote gas sensors. 

Expected to become mainstream in the electronic industry, flexible electronics still face major challenging issues. For polymeric based flexible electronic substrates in particular, these challenges include a lack of electromagnetic shielding capability and poor heat dissipation. Here, we report a highly flexible and thermally-conductive macroscopic polydimethylsiloxane (PDMS) polymer film embedded with copper-coated reduced graphene oxide (rGO) fiber meshes. rGO fibers are assembled into 3D fiber meshes and electroplated with micrometer-thick copper coatings, displaying excellent electrical and thermal conductivities. Oriented in the horizontal and perpendicular directions within the PDMS polymeric matrix, the fiber mesh severs as a highly electrically and thermally-conductive backbone through the in-plane direction. Meanwhile, the fiber mesh also effectively shields electromagnetic interference in the X-band without causing thermal damage. The macroscopic film maintains electrically-insulated in the through-plane direction. Utilizing both the favorable thermal and electrical properties of the graphene fiber-based mesh and the flexibility of the PDMS matrix, our film may exhibit potentials for flexible electronics applications such as wearable electronics thermal management and flexible microwave identification devices.