State-of-the-art research on chemiresistive gas sensors in korea: Emphasis on the achievements of the research labs of professors Hyoun Woo Kim and Sang Sub Kim

This review presents the results of cutting-edge research on chemiresistive gas sensors in Korea with a focus on the research activities of the laboratories of Professors Sang Sub Kim and Hyoun Woo Kim. The advances in the synthesis techniques and various strategies to enhance the gas-sensing performances of metal-oxide-, sulfide-, and polymer-based nanomaterials are described. In particular, the gas-sensing characteristics of different types of sensors reported in recent years, including core- shell, self-heated, irradiated, flexible, Si-based, glass, and metal-organic framework sensors, have been reviewed. The most crucial achievements include the optimization of shell thickness in core- shell gas sensors, decrease in applied voltage in self-heated gas sensors to less than 5 V, optimization of irradiation dose to achieve the highest response to gases, and the design of selective and highly flexible gas sensors-based WS₂ nanosheets. The underlying sensing mechanisms are discussed in detail. In summary, this review provides an overview of the chemiresistive gas-sensing research activities led by the corresponding authors of this manuscript.