Recent Progress on Flexible Room-Temperature Gas Sensors Based on Metal Oxide Semiconductor

Abstract

With the rapid development of the Internet of Things, there is a great demand for portable gas sensors. Metal oxide semiconductors (MOS) are one of the most traditional and well-studied gas sensing materials and have been widely used to prepare various commercial gas sensors. However, it is limited by high operating temperature. The current research works are directed towards fabricating high-performance flexible room-temperature (FRT) gas sensors, which are effective in simplifying the structure of MOS-based sensors, reducing power consumption, and expanding the application of portable devices. This article presents the recent research progress of MOS-based FRT gas sensors in terms of sensing mechanism, performance, flexibility characteristics, and applications. This review comprehensively summarizes and discusses five types of MOS-based FRT gas sensors, including pristine MOS, noble metal nanoparticles modified MOS, organic polymers modified MOS, carbon-based materials (carbon nanotubes and graphene derivatives) modified MOS, and two-dimensional transition metal dichalcogenides materials modified MOS. The effect of light-illuminated to improve gas sensing performance is further discussed. Furthermore, the applications and future perspectives of FRT gas sensors are also discussed.

ZrO2/CeO2-Heterostructured Nanocomposites for Enhanced Carbon Monoxide Gas Sensing

“…Semiconductor metal oxides are emerging as predominant gas sensing materials due to their unique physical and chemically tunable properties in the applications of detecting deleterious, toxic, pollutant, and explosive gases. − The inherent properties of metal oxides along with their composites, like the porous structure which is expressed in the form of a high specific surface area and tunable band gaps with unique semiconducting properties, make them compelling candidates for gas sensing applications. − Metal oxide nanomaterials, in combination with the general benefits, the addition of metal oxides into metal oxide nanomaterials is a new approach which has improved the sensing performance dramatically due to the synergistic effects of these materials. In the case of semiconductor oxides, the structure and surface morphology play a profound role in the sensing properties of gas due to the sensing mechanism, in which the oxygen adsorption and the reaction of oxygen with test gas molecules on the surface of metal oxides correlate with the resistance change. , Nowadays, metal oxide semiconductors with various morphologies and structures have been synthesized by different methods, such as nanosheets, nanocubes, nanowires, nanorods, nanospheres, nanoplates, and nanoflowers. , Further, besides these, hollow nanostructures have revealed immense potential in the field of gas sensors and have attracted strong attention due to their peculiar properties, like enhanced surface areas, good interfacial charge transfer efficiency, increased surface permeability, − and low density.…”

CuO@In2O3/ZnO Core–Shell Nanorods for Triethylamine Detection at Room Temperature

“…TEA gas sensors have attracted extensive attention because of their high sensitivity, low cost, and simple operation. − However, the high operating temperature (200–400 °C) of metal-oxide-based gas sensors may lead to a series of issues, such as the risk of explosion, unsatisfactory stability, and reduced lifetime of a device. It is indispensable to develop room-temperature gas sensors for TEA detection . At present, some researchers have improved the working temperature of triethylamine sensors from the aspects of tunning electronic structure and surface activity, , controlling morphology, , constructing heterostructure, , etc.…”

“…It is indispensable to develop room-temperature gas sensors for TEA detection. 7 At present, some researchers have improved the working temperature of triethylamine sensors from the aspects of tunning electronic structure and surface activity, 8,9 controlling morphology, 10,11 constructing heterostructure, 12,13 etc.…”

SnO2-Based Porous Nanomaterials: Sol-Gel Formation and Gas-Sensing Application

“…Tin oxide [ 32 , 33 , 34 ] as a semiconductor metal oxide has revealed great potential in the field of gas sensing due to its porous structure and reduced size. Especially for tin oxide and its composites, their inherent properties, such as high surface areas and unique semiconducting properties with tunable band gaps, make them compelling for sensing applications [ 35 , 36 , 37 , 38 , 39 , 40 ]. The electrical conductivity of tin dioxide is very sensitive to the state of surfaces in the region of elevated temperatures, at which redox reactions occur on the surface of the oxides.…”