A Survey on Wearable Technology: History, State-of-the-Art and Current Challenges

Coronavirus disease 2019 (COVID-19) has emerged as a pandemic with serious clinical manifestations including death. A pandemic at the large-scale like COVID-19 places extraordinary demands on the world's health systems, dramatically devastates vulnerable populations, and critically threatens the global communities in an unprecedented way. While tremendous efforts at the frontline are placed on detecting the virus, providing treatments and developing vaccines, it is also critically important to examine the technologies and systems for tackling disease emergence, arresting its spread and especially the strategy for diseases prevention. The objective of this article is to review enabling technologies and systems with various application scenarios for handling the COVID-19 crisis. The article will focus specifically on 1) wearable devices suitable for monitoring the populations at risk and those in quarantine, both for evaluating the health status of caregivers and management personnel, and for facilitating triage processes for admission to hospitals; 2) unobtrusive sensing systems for detecting the disease and for monitoring patients with relatively mild symptoms whose clinical situation could suddenly worsen in improvised hospitals; and 3) telehealth technologies for the remote monitoring and diagnosis of COVID-19 and related diseases. Finally, further challenges and opportunities for future directions of development are highlighted.

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Wearable Sensing and Telehealth Technology with Potential Applications in the Coronavirus Pandemic

Abstract We review recent progress in light sensors based on solution-processed materials. Spin-coated semiconductors can readily be integrated with many substrates including as a post-process atop CMOS silicon and flexible electronics. We focus in particular on visible-, near-infrared, and short-wavelength infrared photodetectors based on size-effect-tuned semiconductor nanoparticles made using quantum-confined PbS, PbSe, Bi2S3, and In2S3. These devices have in recent years achieved room-temperature D* values above 1013 Jones, while fully-depleted photodiodes based on these same materials have achieved MHz response combined with 1012 Jones sensitivities. We discuss the nanoparticle synthesis, the materials processing, integrability, temperature stability, physical operation, and applied performance of this class of devices.

http://ma.ecsdl.org/content/MA2013-01/17/757.full.pdf

Colloidal Quantum Dot Photodetectors

The development of flexible piezoelectric nanogenerators has experienced rapid progress in the past decade and is serving as the technological foundation of future state-of-the-art personalized healthcare. Due to their highly efficient mechanical-to-electrical energy conversion, easy implementation, and self-powering nature, these devices permit a plethora of innovative healthcare applications in the space of active sensing, electrical stimulation therapy, as well as passive human biomechanical energy harvesting to third party power on-body devices. This article gives a comprehensive review of the piezoelectric nanogenerators for personalized healthcare. After a brief introduction to the fundamental physical science of the piezoelectric effect, material engineering strategies, device structural designs, and human-body centered energy harvesting, sensing, and therapeutics applications are also systematically discussed. In addition, the challenges and opportunities of utilizing piezoelectric nanogenerators for self-powered bioelectronics and personalized healthcare are outlined in detail.

Piezoelectric nanogenerators for personalized healthcare.

Over the last two decades, advancements in photovoltaic (PV) technology have been flourishing due to the continuous flow of valuable findings. Relevant insights on recent improvements, manufacturing approaches, and various applications of PV technology are provided. Both the PV cell structure and conversion efficiency may significantly contribute to the progression of the PV system. Currently, a wide range of advanced materials and smart technologies are employed within the PV cell's architecture, improving its structure; i.e. PERC/PERL, IBC, HIT/HJT, and MWT. The applications of nanoparticles and thin film technology in PV cell structures have successfully opened new research prospects to boost PV efficiency and overcome certain limitations with the use of CdSe, ZnCds, CdTe, a-Si/µc-Si, CIS, and CIGS. Additionally, constant development in the third generation of OSC methods using OE, OM, and COP are conducted. The improvement of PV backsheet structures and their enhanced optical properties yielded promising results in optimizing solar radiation, reflectance, and PV cell competence. The emergence of hybrid technologies (e.g. PVTE and TPV systems) led to effective solutions for reducing excessive heat that cause deficiency to a PV cell's functionality. Overall, modelling and effectively implementing appropriate parameters (such as diode parameters, optical parameters, circuit current, circuit voltage, fill factor (FF), conversion efficiency, IR, and UV spectral parameters) contributed to the total efficiency and performance modelling of the PV system.

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Photovoltaic applications: Status and manufacturing prospects

Survey of energy scavenging for wearable and implantable devices

Advances in several engineering fields have led to a trend toward miniaturization and portability of wearable biosensing devices, which used to be confined to large tools and clinical settings. Various systems to continuously measure electrophysiological activity through electrical and optical methods are one category of such devices. Being wearable and intended for prolonged use, the amount of noise introduced on sensors by movement remains a challenge and requires further optimization. User movement causes motion artifacts that alter the overall quality of the signals obtained, hence corrupting the resulting measurements. This paper introduces a fully wearable optical biosensing system to continuously measure pulse oximetry and heart rate, utilizing a reflectance-based probe. Furthermore, a novel data-dependent motion artifact tailoring algorithm is implemented to eliminate noisy data due to the motion artifact and measure oxygenation level with high accuracy in real time. By taking advantages of current wireless transmission and signal processing technologies, the developed wearable photoplethysmography device successfully captures the measured signals and sends them wirelessly to a mobile device for signal processing in real time. After applying motion artifact tailoring, evaluating accuracy with a continuous clinical device, the blood oxygenation measurements obtained from our system yielded an accuracy of at least 98%, when compared to a range of 93.6%–96.7% observed before from the same initial data. Additionally, heart rate accuracy above 97% was achieved. Motion artifact tailoring and removal in real time, continuous systems will allow wearable devices to be truly wearable and a reliable electrophysiological monitoring and diagnostics tool for everyday use.

A Wearable Pulse Oximeter With Wireless Communication and Motion Artifact Tailoring for Continuous Use

Lead sulfide colloidal quantum dot photovoltaic cell for energy harvesting from human body thermal radiation

The effect of isopropylamine-capped PbS quantum dots on infrared photodetectors and photovoltaics

There are fewer problems encountered with optical voltage transducers in comparison with their inductive and capacitive counterparts. As a result they are considered as proper candidates for replacing conventional inductive and capacitive transformers. Lighter weight, smaller size, larger dynamic range, wider bandwidth, insensitivity to electromagnetic interference, stability over temperature change, absence of iron core saturation, low maintenance and replacement cost, are some of the advantages of optical voltage transducers over inductive and capacitive transformers. A modified quadrature method is introduced to measure the voltage with the minimum number of sensors. Another advantage of this method is the possibility of improving the accuracy of the measurement by using a correction factor. The correction factor is determined by considering the level of accuracy, environmental conditions and the number of sensors. Simulation results show the validity and effectiveness of this method over a wide range of variation.

Taher Ghomian

Papers

Survey of energy scavenging for wearable and implantable devices

A Wearable Pulse Oximeter With Wireless Communication and Motion Artifact Tailoring for Continuous Use

Lead sulfide colloidal quantum dot photovoltaic cell for energy harvesting from human body thermal radiation

The effect of isopropylamine-capped PbS quantum dots on infrared photodetectors and photovoltaics

Modified quadrature method for accurate voltage measurement in optical voltage transducer