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DOI

Scalably Nanomanufactured Atomically Thin Materials‐Based Wearable Health Sensors

23 Nov 2021-pp 2100120
About: The article was published on 2021-11-23 and is currently open access. It has received 11 citations till now.
Citations
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Journal ArticleDOI
09 May 2022-Small
TL;DR: In this article , the authors comprehensively and critically discuss the syntheses, properties, and emerging applications of the growing family of heteroatom-doped MXenes materials, and present future opportunities and challenges for the study and application of multifunctional high-performance MXenes.
Abstract: Heteroatom doping can endow MXenes with various new or improved electromagnetic, physicochemical, optical, and structural properties. This greatly extends the arsenal of MXenes materials and their potential for a spectrum of applications. This article comprehensively and critically discusses the syntheses, properties, and emerging applications of the growing family of heteroatom-doped MXenes materials. First, the doping strategies, synthesis methods, and theoretical simulations of high-performance MXenes materials are summarized. In order to achieve high-performance MXenes materials, the mechanism of atomic element doping from three aspects of lattice optimization, functional substitution, and interface modification is analyzed and summarized, aiming to provide clues for developing new and controllable synthetic routes. The mechanisms underlying their advantageous uses for energy storage, catalysis, sensors, environmental purification and biomedicine are highlighted. Finally, future opportunities and challenges for the study and application of multifunctional high-performance MXenes are presented. This work could open up new prospects for the development of high-performance MXenes.

28 citations

Journal ArticleDOI
TL;DR: In this article , a stress-deconcentrated ultra-sensitive strain (SDUS) sensor with ultrahigh sensitivity (gauge factor up to 2.3 × 106) and a wide working range (0% −50%) via incorporating notch-insensitive elastic substrate and micro-crack-tunable conductive layer was developed.
Abstract: Recently, rapid advances in flexible strain sensors have broadened their application scenario in monitoring of various mechanophysiological signals. Among various strain sensors, the crack-based strain sensors have drawn increasing attention in monitoring subtle mechanical deformation due to their high sensitivity. However, early generation and rapid propagation of cracks in the conductive sensing layer result in a narrow working range, limiting their application in monitoring large biomechanical signals. Herein, we developed a stress-deconcentrated ultrasensitive strain (SDUS) sensor with ultrahigh sensitivity (gauge factor up to 2.3 × 106) and a wide working range (0%–50%) via incorporating notch-insensitive elastic substrate and micro-crack-tunable conductive layer. Furthermore, the highly elastic amine-based polymer-modified polydimethylsiloxane substrate without obvious hysteresis endows our SDUS sensor with a rapid response time (2.33 ms) to external stimuli. The accurate detection of the radial pulse, joint motion, and vocal cord vibration proves the capability of SDUS sensor for healthcare monitoring and human-machine communications.

6 citations

Journal ArticleDOI
TL;DR: A comprehensive overview of the recent achievements in the application of sensors for different gas detection and indicates the current challenges and future outlooks in this field is provided in this paper , where a wide discussion of various materials-based gas sensors in near future can be attached to the Internet of Things to develop more rigid and highly sensitive gas leakage detectors to avoid accident risks and health threats.
Abstract: The problem of air pollution and an increasing number of hazardous gases leaking into the atmosphere is of growing concern. To protect human and animal life it is necessary to monitor these toxic gases. Gases such as NH3, CO2, CH4, CO, and SO2 can lead to fatal health risks. Gas sensors have attracted extensive attention from academic and commercial fields to monitor such pollutants. The sensing properties, such as measurement sensitivity, response and recovery time, and selectivity, heavily rely on sensing. In this review, the different groups of the sensing materials are described in detail, including metal oxides, metal sulfides, metal ferrites, perovskites, carbon materials, organic polymers, transition metal dichalcogenides, and chalcogenide nanomaterials. The synthesis methods of these compounds and their basic properties are elaborated. Also, morphology has a very important role to tailor the performance of gas sensors. In addition, this review discusses the gas sensing properties of the aforementioned materials along with the explanation of their sensing mechanisms. Special attention is paid to the detection of hazardous organic vapors and toxic gases. The wide discussion of various materials-based gas sensors in near future can be attached to the Internet of Things to develop more rigid and highly sensitive gas leakage detectors to avoid accident risks as well as health threats. This review provides a comprehensive overview of the recent achievements in the application of sensors for different gas detection and indicates the current challenges and future outlooks in this field.

5 citations

Journal ArticleDOI
TL;DR: In this paper , a micromolding-based method is reported for scalable printing of metal nanowires, which enables complex and highly conductive patterns on soft curvilinear and uneven substrates with high resolution and uniformity.
Abstract: Soft electronics using metal nanowires have attracted notable attention attributed to their high electrical conductivity and mechanical flexibility. However, high-resolution complex patterning of metal nanowires on curvilinear substrates remains a challenge. Here, a micromolding-based method is reported for scalable printing of metal nanowires, which enables complex and highly conductive patterns on soft curvilinear and uneven substrates with high resolution and uniformity. Printing resolution of 20 μm and conductivity of the printed patterns of ~6.3 × 106 S/m are achieved. Printing of grid structures with uniform thickness for transparent conductive electrodes (TCEs) and direct printing of pressure sensors on curved surfaces such as glove and contact lens are also realized. The printed hybrid soft TCEs and smart contact lens show promising applications in optoelectronic devices and personal health monitoring, respectively. This printing method can be extended to other nanomaterials for large-scale printing of high-performance soft electronics.

4 citations

Journal ArticleDOI
TL;DR: In this paper , a flexible temperature sensor based on a porous graphene/polydimethylsiloxane sensing layer is developed, which exhibits high sensitivity of 5.203%°C−1 for temperature sensing between 30 and 70°C, and excellent linearity (R2
Abstract: High sensitivity, excellent linearity, and wireless monitoring are strongly desired for the practical application of flexible temperature sensors in real‐time wearable health care. Especially the multichannel body temperature monitoring system has high requirements on the performance of the sensor because it needs to monitor a large amount of data at the same time. Herein, a flexible temperature sensor based on a porous graphene/polydimethylsiloxane sensing layer is developed. The prepared sensor exhibits high sensitivity of 5.203% °C−1 for temperature sensing between 30 and 70 °C, and excellent linearity (R2 = 0.996) in the temperature range from 30 to 70 °C. Based on its excellent performance, the proposed high‐performance temperature sensors can be applied in practical applications such as body temperature monitoring and human breath monitoring under different states including slow breath, normal breath, and fast breath. Moreover, a high‐throughput wireless body temperature monitoring system including wireless sensor modules, a cloud server, and a portable electronic device is constructed, which can achieve a remote and multichannel body temperature monitoring efficiently.

3 citations

References
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Journal ArticleDOI
22 Oct 2004-Science
TL;DR: Monocrystalline graphitic films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands and they exhibit a strong ambipolar electric field effect.
Abstract: We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.

55,532 citations

Journal ArticleDOI
TL;DR: Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena can now be mimicked and tested in table-top experiments.
Abstract: Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top experiments. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications.

35,293 citations

Journal ArticleDOI
10 Nov 2005-Nature
TL;DR: This study reports an experimental study of a condensed-matter system (graphene, a single atomic layer of carbon) in which electron transport is essentially governed by Dirac's (relativistic) equation and reveals a variety of unusual phenomena that are characteristic of two-dimensional Dirac fermions.
Abstract: Quantum electrodynamics (resulting from the merger of quantum mechanics and relativity theory) has provided a clear understanding of phenomena ranging from particle physics to cosmology and from astrophysics to quantum chemistry. The ideas underlying quantum electrodynamics also influence the theory of condensed matter, but quantum relativistic effects are usually minute in the known experimental systems that can be described accurately by the non-relativistic Schrodinger equation. Here we report an experimental study of a condensed-matter system (graphene, a single atomic layer of carbon) in which electron transport is essentially governed by Dirac's (relativistic) equation. The charge carriers in graphene mimic relativistic particles with zero rest mass and have an effective 'speed of light' c* approximately 10(6) m s(-1). Our study reveals a variety of unusual phenomena that are characteristic of two-dimensional Dirac fermions. In particular we have observed the following: first, graphene's conductivity never falls below a minimum value corresponding to the quantum unit of conductance, even when concentrations of charge carriers tend to zero; second, the integer quantum Hall effect in graphene is anomalous in that it occurs at half-integer filling factors; and third, the cyclotron mass m(c) of massless carriers in graphene is described by E = m(c)c*2. This two-dimensional system is not only interesting in itself but also allows access to the subtle and rich physics of quantum electrodynamics in a bench-top experiment.

18,958 citations

Journal ArticleDOI
Changgu Lee1, Xiaoding Wei1, Jeffrey W. Kysar1, James Hone1, James Hone2 
18 Jul 2008-Science
TL;DR: Graphene is established as the strongest material ever measured, and atomically perfect nanoscale materials can be mechanically tested to deformations well beyond the linear regime.
Abstract: We measured the elastic properties and intrinsic breaking strength of free-standing monolayer graphene membranes by nanoindentation in an atomic force microscope. The force-displacement behavior is interpreted within a framework of nonlinear elastic stress-strain response, and yields second- and third-order elastic stiffnesses of 340 newtons per meter (N m(-1)) and -690 Nm(-1), respectively. The breaking strength is 42 N m(-1) and represents the intrinsic strength of a defect-free sheet. These quantities correspond to a Young's modulus of E = 1.0 terapascals, third-order elastic stiffness of D = -2.0 terapascals, and intrinsic strength of sigma(int) = 130 gigapascals for bulk graphite. These experiments establish graphene as the strongest material ever measured, and show that atomically perfect nanoscale materials can be mechanically tested to deformations well beyond the linear regime.

18,008 citations

Journal ArticleDOI
TL;DR: This work reviews the historical development of Transition metal dichalcogenides, methods for preparing atomically thin layers, their electronic and optical properties, and prospects for future advances in electronics and optoelectronics.
Abstract: Single-layer metal dichalcogenides are two-dimensional semiconductors that present strong potential for electronic and sensing applications complementary to that of graphene.

13,348 citations