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The adverse effects of air pollution on respiratory health make air quality monitoring with high spatial and temporal resolutions essential especially in cities. Despite considerable interest and efforts, the application of various types of sensors is considered immature owing to insufficient sensitivity and cross-interference under ambient conditions. Here, a fully integrated chemiresistive sensor array (CSA) with parts-per-trillion sensitivity is demonstrated with its application for on-road NO x monitoring. An analytical model is suggested to describe the kinetics of the sensor responses and quantify molecular binding affinities. Finally, the full characterization of the system is connected to implement on-road measurements on NO x vapor with quantification as its ultimate field application. The obtained results suggest that the CSA shows potential as an essential unit to realize an air-quality monitoring network with high spatial and temporal resolutions.

The adverse effects of air pollution on respiratory health make air quality monitoring with high spatial and temporal resolutions essential especially in cities. Despite considerable interest and efforts, the application of various types of sensors is considered immature owing to insufficient sensitivity and cross-interference under ambient conditions. Here, a fully integrated chemiresistive sensor array (CSA) with parts-per-trillion sensitivity is demonstrated with its application for on-road NO x monitoring. An analytical model is suggested to describe the kinetics of the sensor responses and quantify molecular binding affinities. Finally, the full characterization of the system is connected to implement on-road measurements on NO x vapor with quantification as its ultimate field application. The obtained results suggest that the CSA shows potential as an essential unit to realize an air-quality monitoring network with high spatial and temporal resolutions.

2D transition metal dichalcogenides (TMDs) have significant research interests in various novel applications due to their intriguing physicochemical properties. Notably, one of the 2D TMDs, SnS2, has superior chemiresistive sensing properties, including a planar crystal structure, a large surface‐to‐volume ratio, and a low electronic noise. However, the long‐term stability of SnS2 in humid conditions remains a critical shortcoming towards a significant degradation of sensitivity. Herein, it is demonstrated that the subsequent self‐assembly of zeolite imidazolate framework (ZIF‐8) can be achieved in situ growing on SnS2 nanoflakes as the homogeneous porous materials. ZIF‐8 layer on SnS2 allows the selective diffusion of target gas species, while effectively preventing the SnS2 from severe oxidative degradation. Molecular modeling such as molecular dynamic simulation and DFT calculation, further supports the mechanism of sensing stability and selectivity. From the results, the in situ grown ZIF‐8 porous membrane on 2D materials corroborates the generalizable strategy for durable and reliable high‐performance electronic applications of 2D materials. [ABSTRACT FROM AUTHOR]

The adverse effects of air pollution on respiratory health make air quality monitoring with high spatial and temporal resolutions essential especially in cities. Despite considerable interest and efforts, the application of various types of sensors is considered immature owing to insufficient sensitivity and cross‐interference under ambient conditions. Here, a fully integrated chemiresistive sensor array (CSA) with parts‐per‐trillion sensitivity is demonstrated with its application for on‐road NOx monitoring. An analytical model is suggested to describe the kinetics of the sensor responses and quantify molecular binding affinities. Finally, the full characterization of the system is connected to implement on‐road measurements on NOx vapor with quantification as its ultimate field application. The obtained results suggest that the CSA shows potential as an essential unit to realize an air‐quality monitoring network with high spatial and temporal resolutions. [ABSTRACT FROM AUTHOR]

A novel transient electronics technology that is capable of completely dissolving or decomposing in certain conditions after a period of operation offers unprecedented opportunities for medical implants, environmental sensors, and other applications. Here, we describe a biodegradable, flexible silicon-based electronic system that detects NO species with a record-breaking sensitivity of 136 Rs (5 ppm, NO2) and 100-fold selectivity for NO species over other substances with a fast response (~30 s) and recovery (~60 s). The exceptional features primarily depend on not only materials, dimensions, and design layouts but also temperatures and electrical operations. Large-scale sensor arrays in a mechanically pliable configuration exhibit negligible deterioration in performance under various modes of applied loads, consistent with mechanics modeling. In vitro evaluations demonstrate the capability and stability of integrated NOx devices in severe wet environments for biomedical applications. Biomedical electronics: Getting a whiff of bad health Degradable devices that monitor health by measuring gases emitted by the body have been developed by researchers in South Korea, the UK and the USA. Biodegradable electronics, devices that decay naturally over time, are potentially useful for medical devices. They can be used internally as implants that don't need to be surgically removed or externally as wearable health monitors. Chong-Yun Kang and Suk-Won Hwang from Korea University in Seoul and their colleagues have developed a biodegradable, flexible silicon nanomembrane to detect nitric oxide with a high sensitivity andselectivity and a fast response time. Nitric oxide sensors are important for health monitoring as the gas is associated with many physiological processes including regulation of the vascular system and blood flow. In vitro experiments in aqueous solutions demonstrated the feasibility of their devices for disposable medical implants. Soft, transient silicon-based gas sensing system capable of detecting nitrogen oxides with remarkable sensitivity and selectivity is presented in this report. The results provide materials, device layouts, manufacturing process, and theorectical modeling illlustrating the capabilities and operational aspects. In vitro experiments demonstrate the possibilities for disposable environmental monitors and temporary biomedical implants. [ABSTRACT FROM AUTHOR]