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In this paper, YSZ-based high performance acetone sensor was successfully developed for intelligent medical service, environmental monitoring, and safety production of smart city. New type spinel electrode sensing materials NiGa x Al 2-x O 4 (x = 0, 0.6, 1 and 1.4) were synthesized by a sol-gel method. Compared to the other sensing electrode materials, NiGa 0.6 Al 1.4 O 4 had the highest electrochemical catalytic activity to acetone, and the sensor based on NiGa 0.6 Al 1.4 O 4 -SE performed the best sensing performance of −48 mV to 10 ppm acetone. Moreover, the present acetone sensor has a wide detection range of 0.2–1000 ppm, with sensitivity of −45 mV/decade, meeting the field of diabetic non-invasive diagnosis and real-time in-situ environmental monitoring. In addition, the device also performs excellent repeatability, acceptable selectivity, terrific humidity resistance and marvelous long-term stability during continuous measurements over 30 days. Overall, based on its excellent sensing performance, the developed sensor has marvelous application prospects for acetone detection in intelligent medical service, environmental monitoring, and safety production fields of smart city. • NiGa x Al 2-x O 4 were firstly used as sensing electrode for YSZ-based acetone sensor. • The sensor with NiGa 0.6 Al 1.4 O 4 -SE performed the largest response to 10 ppm acetone. • The low detection limit can reach 200 ppb and the detection range is 0.2–1000 ppm • The sensor has excellent repeatability, humidity resistance and long-term stability. [ABSTRACT FROM AUTHOR]

Abstract This paper proposes an ultrafast-laser process for ablating multilayer graphene film to form the conductive electrodes for a gas sensor module with wireless circuits. In this study, a picosecond laser source was directly used to perform double scanning for precisely fabricating the spiral electrode pattern as the sensing test region. The ablated surface of multilayer graphene structures fabricated using sufficiently strong pulses with a pulse width of 7 ps and a wavelength of 532 nm was investigated through scanning electron microscopy. The graphene-based electrode was integrated with wireless circuits to form a gas sensor module. The relationship between the spiral electrode design and sensitivity to gas detection was analyzed. Electrical detection of gas was studied by employing different electrode designs, and change in the detection limit at room temperature with change in resistance was examined. Furthermore, the role of graphene-based devices comprising spiral electrodes fabricated using the laser process and integrated with wireless circuits to form a module in gas detection was analyzed. Graphical abstract Unlabelled Image Highlights • Picosecond laser ablation of multilayer graphene for gas detection was investigated. • Design of spiral electrode device as the sensing region was discussed. • Graphene-based device with wireless circuits to form a gas sensor module. [ABSTRACT FROM AUTHOR]

Abstract With the development of technology, process control has become central to the working of modern industries as well as devices. Sensors are at the heart of these advances; where, the need for high sensitivity, quick response as well as recovery, and low power consumption is imperative at economic prices. The use of nanomaterials has shown to greatly enhance the sensing performance of a device owing to the large surface area of such materials. The large surface-to-volume and pitted structure, along with extraordinary electrical and thermal conductivities, make it most favorable material for gas sensing applications. Major advancements in the CNTs based gas sensors involve the enhancing the sensitivity and selectivity of the nanotubes. This can be achieved by specific functionalization of CNTs with a variety of materials such as noble metals, metal oxides, polymers, etc. It has been found that, for sensor applications, modifications of CNTs with certain materials can enhance the selectivity and sensitivity of CNTs and make it sensitive towards several harmful gases. In this article, we present a comprehensive analysis of the past as well as present day CNTs gas sensors technology. The study presented in this paper are helpful to develop advanced devices with the application of highly efficient sensors. [ABSTRACT FROM AUTHOR]

Abstract: In previous reports, we have investigated on the influence of current transport mechanism on the sensitivity of InP Schottky and pseudo-Schottky diodes, for nitrogen dioxide detection. In this paper, the influence of the metal nature and the structure of the rectifying contact on the sensing layer are highlighted. More especially, we will focus on the behavior of these Schottky structures during and after their exposures to nitrogen dioxide (NO2) and ozone (O3). In this context, two types of structures have been studied: the simple Schottky diodes and the more elaborated structures called pseudo-Schottky. These diodes are realized with Au or Pd as metals. First, we will describe samples preparation and electrical characterization of the two types of structures. Then, we will compare sensor responses of these different structures under NO2 and O3. Finally, to better understand the action of these gases on the sensitive layer (the Schottky contact), X-rays photoelectron spectroscopy (XPS) is performed to follow the evolution of the metallic layer. The poisoning effect of active sites, which appears after NO2 and O3 expositions, is illustrated by comparative study of the active layer before and after exposure. [Copyright &y& Elsevier]