Multiplexed Gas Sensor: Fabrication Strategies, Recent Progress, and Challenges

Abstract

Due to miscellaneous toxic gases in the vicinity, there is a burgeoning need for advancement in the existing gas sensing technology not only for the survival of mankind but also for the industries based in various fields such as beverage, forestry, health care, environmental monitoring, agriculture, and military security. A gas sensor must be highly selective toward a specific gas in order to avoid incorrect signals while responding to nontarget gases. This may lead to complex scenarios depicting sensor defects, such as low selectivity and crosssensitivity. Therefore, a multiplex gas sensor is required to address the problems of cross selectivity by combining different gas sensors, signal processing, and pattern recognition techniques along with the currently employed gas sensing technologies. The different sensing materials used in these sensor arrays will produce a unique response signal for developing a set of identifiers as the input that can be used to recognize a specific gas by its "fingerprint". This review provides a comprehensive review of chemiresistive-based multiplex gas sensors, including various fabrication strategies from expensive to lowcost techniques, advances in sensing materials, and a gist of various pattern recognition techniques used for both rigid and flexible gas sensor applications. Finally, the review assesses the current state-of-the-art in multiplex gas sensor technology and discusses various challenges for future research in this direction.

Recent Advances in Advanced Micro and Nanomanufacturing for Wastewater Purification

“…Photolithography stands as a foundational technique within the realm of microfabrication, widely acknowledged for its capacity to produce intricate patterns on various substrates. The process relies on light-sensitive materials known as photoresists, which undergo chemical transformations upon exposure to specific wavelengths of light . Through a combination of selective exposure and subsequent development steps, microstructures possessing finely detailed features can be meticulously etched onto the substrate.…”

“…The process relies on lightsensitive materials known as photoresists, which undergo chemical transformations upon exposure to specific wavelengths of light. 13 Through a combination of selective exposure and subsequent development steps, microstructures possessing finely detailed features can be meticulously etched onto the substrate.…”

Selective Detection of NH3 Gas by Ti3C2Tx Sensors with the PVDF-ZIF-67 Overlayer at Room Temperature

“…4 Materials for detecting harmful gases have seen numerous advances during the past few decades, notably carbonaceous materials 5 and semiconductor metal oxides. 6 Still, a majority of the aforementioned compounds need high temperatures while operating and have energy consumption. As a result, scientists have examined low-temperature gas sensors that can detect NH 3 , such as those that use MoS 2 , 7 graphene, 8 and other low-dimensional noble-metal doping nanocomposites.…”

“…Currently, chemical sensors operating at ambient temperature have become an entirely novel sensing device with reduced device power requirements, improved safety, and wearables projected to replace the traditional sensors in the coming years . Materials for detecting harmful gases have seen numerous advances during the past few decades, notably carbonaceous materials and semiconductor metal oxides . Still, a majority of the aforementioned compounds need high temperatures while operating and have energy consumption.…”

Influence of the Pd Oxidation State in PdNi Thin Films on Surface Acoustic Wave Hydrogen Sensing Performance

“…In the context of the growing low-carbon economy (LCE), hydrogen (H 2 ) energy has gained widespread usage in various applications, such as hydrogen fuel cell vehicles and hydrogen chemical industry. − However, hydrogen exhibits notable attributes, including rapid diffusion (0.61 cm 2 /s), low ignition energy (∼0.2 mJ), and a wide flammability range in air (4–75 v/v%). − These attributes lead to safety risks in H 2 production, transportation, and utilization. To ensure the safe utilization of H 2 , there is a high demand for highly sensitive H 2 sensors with excellent long-term stability. , Depending on the underlying hydrogen sensing mechanisms, H 2 sensors can be categorized into different types, such as mechanical or electrochemical change-based, resistance-based, thermal-based, acoustically assisted, catalytic activity-based, and optically assisted sensors. − Among these, surface acoustic wave (SAW) hydrogen sensors have emerged as a promising technology due to their remarkable advantages in terms of response speed, sensitivity, and low-power consumption. , …”