Flexible gas sensors capable of working at room temperature are in great demand for the Internet-of-things (IoT) revolution. Although molybdenum disulfide (MoS 2 ) is a promising material for NO 2 gas sensing, the influence of morphology on sensing performance is not well understood. Existing gas sensors using conventional electrodes involve complex fabrication processes, resulting in high cost, thus severely limiting their ubiquitous application. In this paper, the design, fabrication, and characterization of MoS 2 gas sensors utilizing laser-induced graphene (LIG) electrodes are presented. Morphology evolution of MoS 2 nanostructures and the resulting gas sensing performance trade-offs are discussed. The flexibility and mechanical robustness of the sensors utilizing LIG electrodes have also been confirmed to be excellent. Overall, high performance in gas sensing combined with low susceptibility to mechanical damage enables the sensor to serve a variety of wearable sensory applications.

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a b s t r a c tHigh-performance, area and power efficient hardware implementation of decimal multiplication is preferred to slow software simulations in various key scientific and financial applications, where errors caused by converting decimal numbers into their approximate binary representations are unacceptable. This paper presents a parallel architecture for fixed-point 8421-BCD-based decimal multiplication. In essence, it applies a hybrid 8421-5421 recoding scheme to generate partial products, and accumulates them with 8421 carry-lookahead adders organized as a tree structure. In addition, we propose a 4221-BCD-based decimal multiplier that is built upon a novel 4221-BCD full adder; operands of this 4221 multiplier are directly represented in the 4221 BCD. The proposed 16 Â 16 decimal multipliers are compared with other best-known decimal multiplier designs with a TSMC 90-nm technology, and the evaluation results show that the proposed 8421-5421 multiplier achieves the lowest delay and area, as well as the highest power efficiency, among all the existing hardware-based BCD multipliers.

Nitrogen dioxide (NO2) is a prominent air pollutant that is harmful to both the environment and human health. Conventional NO2 sensors that are designed to operate at room temperature often...

Ultra-sensitive pressure sensing is provided hierarchically, on the nanoscale by contact between silver nanoflakes and LIG nanosheets, and on the microscale by contact between AgMFs and LIG.

Black phosphorus (BP) nanosheets represent a promising class of two-dimensional (2D) materials for nitrogen dioxide (NO 2 ) sensing, but its practical application is limited by complex preparation processes. In this paper, we present an ultrasensitive and selective chemiresistive NO 2 sensor based on liquidphase-exfoliated BP nanosheets. The unique combination of probe sonication and ice-water bath sonication is capable of producing BP nanosheets of various controllable sizes. Sensing characterization shows that the BP nanosheet-based sensor exhibits a large sensing response of 88%, a high selectivity, and a full recovery toward 100 ppb NO 2 gas at room temperature, which represents a substantial improvement over recently reported designs. The proposed preparation method for nanosheets with tunable gas-sensing properties is instrumental to the practical applications of BP toward high-performance, portable, and ubiquitous NO 2 -sensing applications.