Bio-integrated wearable systems can measure a broad range of biophysical, biochemical, and environmental signals to provide critical insights into overall health status and to quantify human performance. Recent advances in material science, chemical analysis techniques, device designs, and assembly methods form the foundations for a uniquely differentiated type of wearable technology, characterized by noninvasive, intimate integration with the soft, curved, time-dynamic surfaces of the body. This review summarizes the latest advances in this emerging field of “bio-integrated” technologies in a comprehensive manner that connects fundamental developments in chemistry, material science, and engineering with sensing technologies that have the potential for widespread deployment and societal benefit in human health care. An introduction to the chemistries and materials for the active components of these systems contextualizes essential design considerations for sensors and associated platforms that appear in f...

Bio-Integrated Wearable Systems: A Comprehensive Review

The intensity of the infrared radiation emitted by objects is mainly a function of their temperature. In infrared thermography, this feature is used for multiple purposes: as a health indicator in medical applications, as a sign of malfunction in mechanical and electrical maintenance or as an indicator of heat loss in buildings. This paper presents a review of infrared thermography especially focused on two applications: temperature measurement and non-destructive testing, two of the main fields where infrared thermography-based sensors are used. A general introduction to infrared thermography and the common procedures for temperature measurement and non-destructive testing are presented. Furthermore, developments in these fields and recent advances are reviewed.

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Infrared thermography for temperature measurement and non-destructive testing.

Major growth in the image sensor market is largely as a result of the expansion of digital imaging into cameras, whether stand-alone or integrated within smart cellular phones or automotive vehicles. Applications in biomedicine, education, environmental monitoring, optical communications, pharmaceutics and machine vision are also driving the development of imaging technologies. Organic photodiodes (OPDs) are now being investigated for existing imaging technologies, as their properties make them interesting candidates for these applications. OPDs offer cheaper processing methods, devices that are light, flexible and compatible with large (or small) areas, and the ability to tune the photophysical and optoelectronic properties − both at a material and device level. Although the concept of OPDs has been around for some time, it is only relatively recently that significant progress has been made, with their performance now reaching the point that they are beginning to rival their inorganic counterparts in a number of performance criteria including the linear dynamic range, detectivity, and color selectivity. This review covers the progress made in the OPD field, describing their development as well as the challenges and opportunities.

Organic Photodiodes: The Future of Full Color Detection and Image Sensing

Over the past two decades, several advances have been made in micromachined sensors and actuators. As the field of microelectromechanical systems (MEMS) has advanced, a clear need for the integration of materials other than silicon and its compounds into micromachined transducers has emerged. Piezoelectric materials are high energy density materials that scale very favorably upon miniaturization and that has led to an ever-growing interest in piezoelectric films for MEMS applications. At this time, piezoelectric aluminum-nitride-based film bulk acoustic resonators (FBAR) have already been successfully commercialized. Future innovations and improvements in inertial sensors for navigation, high-frequency crystal oscillators and filters for wireless applications, microactuators for RF applications, chip-scale chemical analysis systems and countless other applications hinge upon the successful miniaturization of components and integration of piezoelectrics and metals into these systems. In this article, a comprehensive review of micromachined piezoelectric transducer technology will be presented. Piezoelectric materials in bulk and thin film forms will be reviewed and fabrication techniques for the integration of these materials for microsensor applications will be presented. Recent advances in various piezoelectric microsensors will be presented through specific examples. This review will conclude with a critical assessment of the future trends and promise of this technology.

https://iopscience.iop.org/article/10.1088/0957-0233/20/9/092001/pdf

Piezoelectric MEMS sensors: state-of-the-art and perspectives

Graphene-based gas/vapor sensors have attracted much attention in recent years due to their variety of structures, unique sensing performances, room-temperature working conditions, and tremendous application prospects, etc. Herein, we summarize recent advantages in graphene preparation, sensor construction, and sensing properties of various graphene-based gas/vapor sensors, such as NH3, NO2, H2, CO, SO2, H2S, as well as vapor of volatile organic compounds. The detection mechanisms pertaining to various gases are also discussed. In conclusion part, some existing problems which may hinder the sensor applications are presented. Several possible methods to solve these problems are proposed, for example, conceived solutions, hybrid nanostructures, multiple sensor arrays, and new recognition algorithm.

/pdf/a-review-on-graphene-based-gas-vapor-sensors-with-unique-3yvc87wwd5.pdf

A Review on Graphene-Based Gas/Vapor Sensors with Unique Properties and Potential Applications

Purpose – The purpose of this paper is to provide an introduction to micro-electromechanical systems (MEMS) sensors and their commercialisation and to consider a number of recent applications, markets and product developments. Design/methodology/approach – Following an introduction and a brief historical background to MEMS sensors and their commercialisation, the paper describes a selection of recent applications, with an emphasis on high volume uses. Various market figures are included to place these applications in a commercial context. Sensors for both physical variables and gases are considered. Findings – The paper shows that MEMS sensor applications continue to grow in the automotive, consumer electronics and other industries, which consume many millions of sensors annually. New product developments reflect the requirement for smaller and lower-cost sensors with enhanced performance and greater functionality. Markets for physical sensors dominate but MEMS technology is making progressive inroads in ...

Recent developments in MEMS sensors: a review of applications, markets and technologies

Purpose – To describe the historical development of micro‐electromechanical system (MEMS) sensor technology, to consider its current use in physical, gas and chemical sensing and to identify and discuss future technological trends and directions.Design/methodology/approach – This paper identifies the early research which led to the development of MEMS sensors. It considers subsequent applications of MEMS to physical, gas and chemical sensing and discusses recent technological innovations.Findings – This paper illustrates the greatly differing impacts exerted on physical, gas and chemical sensing by MEMS technology. More recent developments are discussed which suggest strong market prospects for MEMS devices with analytical capabilities such as microspectrometers, micro‐GCs, microfluidics, lab‐on‐a‐chip and BioMEMS. This view is supported by various market data and forecasts.Originality/value – This paper provides a technical and commercial insight into the applications of MEMS technology to physical and m...

MEMS sensors: past, present and future

Purpose



– This paper aims to provide details of the major optical gas sensing techniques and their applications. 




Design/methodology/approach



– Following an introduction, this paper first identifies the major gas sensing technologies and provides an overview of optical sensing techniques. The sources and impact of the gases most frequently sensed by optical methods are listed. Three non-absorption-based and nine absorption-based methods and their main applications are then described in detail. Brief concluding comments are drawn. 




Findings



– All manner of optical gas sensing techniques have been commercialised and while the majority are absorption-based, several other methods also play a significant role. Some optical gas sensors offer advanced capabilities such as remote monitoring, the creation of 2D and 3D distribution maps, detection of parts per trillion levels and even the visualisation of gases in real time. They play a vital role in protecting workers from hazardous gases, controlling and minimising air pollution and monitoring the atmospheric environment, as well as being used in the food, medical, process, power generation and other industries. 




Originality/value



– This paper provides a detailed insight into optical gas sensing techniques and their uses.

Detecting gases with light: a review of optical gas sensor technologies

Purpose



– This article aims to provide an insight into recent deliberations on the possibility of a global sensor market reaching one trillion units per annum within the next decade. 




Design/methodology/approach



– Following an introduction, which includes details of the TSensors Summit, this article discusses existing high volume sensor applications with multi-billion unit growth prospects. It then considers certain new and emerging applications, including the Internet of Things. This is followed by technological considerations and a brief discussion. 




Findings



– The possibility of a global sensor market reaching one trillion units per annum within the next decade is the topic of serious debate. Several applications representing multi-billion levels have been identified and the ongoing TSensors Summit activities seek to identify further high volume, high growth uses and the factors that will stimulate them. While MEMS will play a central role, other, often new sensor technologies will be vital to achieving the trillion unit level. 




Originality/value



– This article provides a timely review of recent deliberations surrounding the feasibility of achieving a global, trillion sensor market.

Towards the trillion sensors market

Purpose – The purpose of this paper is to review the development of energy harvesting techniques and their use with wireless, self‐powered sensors.Design/methodology/approach – This paper first considers the need for wireless sensors and then discusses a number of products and recent development activities.Findings – Energy harvesting devices based on electrodynamic, piezoelectric and thermoelectric effects, implemented through electromechanical, microelectromechanical systems and nanotechnological approaches, are attracting strong academic and commercial interest. A limited number of sensors and systems exploiting these effects are in production and many more are under development. Some actual and anticipated applications include industrial condition monitoring, structural monitoring and healthcare.Originality/value – This provides a technical insight into energy harvesting techniques and their applications to wireless sensing.

Robert Bogue

Papers

Recent developments in MEMS sensors: a review of applications, markets and technologies

MEMS sensors: past, present and future

Detecting gases with light: a review of optical gas sensor technologies

Towards the trillion sensors market

Energy harvesting and wireless sensors: a review of recent developments