Synthesis and gas sensing properties of WS2 nanocrystallites assembled hierarchical WS2 fibers by electrospinning

Nanomaterials for IoT Sensing Platforms and Point-of-Care Applications in South Korea

Herein, state-of-the-art research advances in South Korea regarding the development of chemical sensing materials and fully integrated Internet of Things (IoT) sensing platforms were comprehensively reviewed for verifying the applicability of such sensing systems in point-of-care testing (POCT). Various organic/inorganic nanomaterials were synthesized and characterized to understand their fundamental chemical sensing mechanisms upon exposure to target analytes. Moreover, the applicability of nanomaterials integrated with IoT-based signal transducers for the real-time and on-site analysis of chemical species was verified. In this review, we focused on the development of noble nanostructures and signal transduction techniques for use in IoT sensing platforms, and based on their applications, such systems were classified into gas sensors, ion sensors, and biosensors. A future perspective for the development of chemical sensors was discussed for application to next-generation POCT systems that facilitate rapid and multiplexed screening of various analytes.

Design of p-p heterojunctions based on CuO decorated WS2nanosheets for sensitive NH3gas sensing at room temperature

Tungsten disulfide (WS₂) nanosheets (NSs) have become a promising room-temperature gas sensor candidate due to their inherent high surface-to-volume ratio, tunable electrical properties, and high on-state current density. For further practical applications of WS₂-based gas sensors, it is still necessary to overcome the insensitive response and incomplete recovery at room temperature. In this work, we controllably synthesized high-performance ammonia (NH₃) gas sensor based on CuO decorated WS₂NSs. The optimized p-p WS₂/CuO heterojunctions improve the surface catalytic effect, thereby enhancing the gas-sensing performance. The pure WS₂NSs-based gas sensors showed a low response and an incomplete recovery in the case of NH₃sensing. After the functionalization of CuO nanoparticles, the WS₂/CuO heterostructure-based gas sensor exhibits an improved response value of 40.5% to 5  ppm NH₃and full recoverability without any external assistance. Density functional theory calculations illustrate that the adsorption of CuO for NH₃is much superior to WS₂. The p-p heterojunctions strategy demonstrated in this work has great potential in the design of sensitive materials for gas sensors, and provides useful guidance for enhancing the room-temperature sensitivity and recoverability.

Transition metal sulfides meet electrospinning: versatile synthesis, distinct properties and prospective applications

One-dimensional (1D) electrospun nanomaterials have attracted significant attention due to their unique structures and outstanding chemical and physical properties such as large specific surface area, distinct electronic and mass transport, and mechanical flexibility. Over the past years, the integration of metal sulfides with electrospun nanomaterials has emerged as an exciting research topic owing to the synergistic effects between the two components, leading to novel and interesting properties in energy, optics and catalysis research fields for example. In this review, we focus on the recent development of the preparation of electrospun nanomaterials integrated with functional metal sulfides with distinct nanostructures. These functional materials have been prepared via two efficient strategies, namely direct electrospinning and post-synthesis modification of electrospun nanomaterials. In this review, we systematically present the chemical and physical properties of the electrospun nanomaterials integrated with metal sulfides and their application in electronic and optoelectronic devices, sensing, catalysis, energy conversion and storage, thermal shielding, adsorption and separation, and biomedical technology. Additionally, challenges and further research opportunities in the preparation and application of these novel functional materials are also discussed.