查看更多>>摘要：Self-healable wearable devices with tactile directional sensitivity have attracted significant attention due to their damage-free sustainable and precise detection of directional body motions in various applications such as hand gesture monitoring and electrooculography (EOG) sensors. In this study, a self-powered triboelectric sensor with tactile directional sensitivity and self-healing property based on the dielectric multilayers of aligned silver nanowire (AgNW) composite gel sandwiched between self-healable polymers has been developed. Its output performances are superior to those of similar devices without the AgNW gel due to the stronger interfacial polarization of the dielectric multilayers and charge trapping by AgNWs. Moreover, the aligned AgNW composite gel possesses anisotropic dielectric properties, which enhances the contact direction-sensitive triboelectric performance of the sensor during rolling or rubbing motions. The fabricated sensor can be used in wearable EOG and electrocardiography applications because of the ability to monitor extremely weak blood pulse waves in the temporal artery around the human eye, while its directional force sensitivity allows differentiating eight eye movement directions. The successful use of the multilayered structure containing the self-healable and aligned AgNW composite gel as a triboelectric dielectric material opens a new avenue for designing self-healable wearable sensors with tactile directional sensitivity.
查看更多>>摘要：Self-charging power systems (SCPSs) that combine energy harvest/store technologies have attracted extensive attention owing to their vast potential in the Internet of things (IoT). Still, the long charging time is a severe obstacle to the practical use of SCPSs. Herein, we have successfully prepared a high-efficiency SCPS composed of a performance-enhanced rotational hybrid nanogenerator (R-HNG) and high-energy-density asymmetric supercapacitor (ASC). The R-HNG consists of a rotational triboelectric nanogenerator (R-TENG) and an electromagnetic generator (EMG), exhibiting superior charging performance. Among them, the output characteristics of the R-TENG can be enhanced by adjusting the work function difference between the friction layer and electrode. The working principle of the R-HNG is systematically explained by both Kelvin probe force microscope (KPFM) and finite element simulation. Meanwhile, the as-prepared ASC based on honeycomb-like NiCo-layered double hydroxides (LDH) nanosheets are used as an energy storing device within SCPS. The SCPS can reach 5.9 V after 120 s under a rotation speed of 200 rpm, which can power a homemade positioning device for outdoor search and rescue. This work provides a novel and effective solution for constructing high-performance SCPSs and is expected to accelerate the development of SCPSs in the IoT.
查看更多>>摘要：Shape-controlled nano-silvers have great promise for the practical applications in devices due to their unique electronic properties. Although variously complicated nano-silver structures have been reported, the accurate control of one-dimension (1D) oriented assembly of Ag crystals remains challenging. Here, we innovatively fabricated Ag nano-lines (AgNLs) with pair directed arrays along the parallel boundary of the templated nanofibers. The multi-stage template mechanism of polyvinyl pyrrolidone (PVP) molecules based on electrospinning and UV irradiation played an indispensable effect in the coherent single-nanoparticle assembly of Ag nanocrystals in the nanofibers. Using the electrochemically assisted analysis, we found the special electron conduction and sensibility of water molecules in the AgNLs. Further, based on the tightly connected and gapped assembly characteristics of the AgNLs, we integrated the AgNLs arrays as the nanoscale humidity sensors which behaved the different sensing properties at low, middle and high relative humidity (RH). Our research demonstrated the application of AgNLs in the humidity-relative fields and provided a new strategy for fabricating the nanoscale 1D directed non-contact humidity sensors.
查看更多>>摘要：Two-dimensional (2D) semiconductor-based devices are mostly using in-plane direction current in their device architecture, to justify the novelty of 2D-like ultrathin electron devices beyond conventional 3D devices. Those ultrathin 2D devices, however, would unavoidably meet high contact resistance issue. In the present study, thick 2D-layered crystals are rather chosen for a meaningful vertical device, which alleviates the contact resistance issue using a large contact area. Here, we have fabricated Pt/120 nm-thick MoSe2 Schottky diodes with different Ohmic metal contacts of Au, Ti/Au, and MoTi/Au. These diodes are then monolithically integrated with a capacitor of -20 nm-thick h-BN or 50 nm-thick ALD Al2O3. This way, van der Waals crystal radios are successfully fabricated for wireless RF energy harvesting. In terms of crystal radio device performance, the best results come from Pt/n-MoSe2 Schottky diode with MoTi contact and h-BN capacitor combination. This superiority is attributed to the excellent Ohmic behavior of MoTi alloy contact. At last, when AM demodulation experiments are conducted with 1 MHz carrier frequency/audio frequency-mixed signals, the crystal radio with MoTi demonstrates the highest output DC voltage envelope, allowing loud audio sound.
查看更多>>摘要：Harvesting energy from raindrops has attracted extensive efforts due to the wide distribution of precipitation and vast potential applications. Among the various approaches developed for this purpose, droplets-based electricity generators (DEGs) based on electrostatic induction have been becoming an outstanding option in the aspect of output voltage and instantaneous power density. Performance dependence of DEGs on the device configuration and the dominating factors have to be revealed for the further optimization. Here, we comprehensively inves-tigated the performance of DEGs with three different configurations, i.e., bottom-electrode, top-electrode and double-electrode, and found that water-to-ground capacitance played an important role in determining the de -vice output. Besides, the conductivity of water shows notable influence on the device performance, tap water with a conductivity around 300 mu S/cm shows the highest efficiency in our measurements. Adapting an optimized power management circuit, the pulsed-like output of DEGs is converted to a constant voltage output of variable amplitudes, which is successfully used to charge a smart phone. Our results shed light on possible ways to further optimize the DEG configuration and their potential applications.
查看更多>>摘要：Smart skins and smart textiles equipped with strain sensors for motion detection are of prime significance for personalized health monitoring, lifestyle and fitness applications. Yet, the dependence of these devices on wired power supplies and rigid batteries limits their use in everyday settings. Here, we report self-powered and highly elastic strain sensors withstanding stretching to 200% for monitoring the human motion. The sensor is based on a torsional-spring-shaped coil of liquid metal wound around an elastomeric tubing and equipped with a tiny piece of a magnetic ring. The energy is harvested from the body motion relying on the Faraday's law of electromagnetic induction when the coil is exposed to a time-varying magnetic field of the magnetic ring upon the mechanical deformation of the strain sensor. The max short-circuit current is 2 mA, which is much higher than previous work, and the peak power of our device is 20 mu W, sufficiently high to drive conventional low-power electronics. We demonstrate the application potential of our sensor for wearable electronics for monitoring the motion of arms and legs during fitness workout and riding bicycle. The sensor can measure motion of fingers and wrist for health applications and establish wireless control of robotic hands.
查看更多>>摘要：Integrating multifunctionality into wearable electronics is becoming a tendency to meet the complexity of daily practical applications in the monitoring of human health and exercise. However, the types of multifunctional electronic devices are limited and the fabrication of the devices is usually complicated. Herein, we develop an electronic smart band-aid, which endows traditional band-aid new functionalities, by simply coating the traditional band-aid with silver nanowire network and polytetrafluoroethylene/polydimethylsiloxane mixture. The fabricated smart band-aid exhibits excellent triboelectric performances (V-OC = 380 V, I-SC = 23 mu A, and power density = 1.13 W m(-2)) and high strain sensing performances (working strain range of similar to 110%, and sensitivity as high as 7.71). It can be used not only for wound protection but also for self-powered sensing of movements and human-machine interaction. Our work provides a cheap, convenient, and effective approach for multifunctional sensing applications in the field of wearable and flexible electronics.
查看更多>>摘要：Smart and wearable electromagnetic (EM) functional materials that can reasonably use EM energy and prevent EM pollution are of great significance to the future information society, but their design and preparation are still challenging. Here, a multifunctional EM response film is prepared based on a magnetic liquid metal droplet-filled elastomer with magnetic field-induced anisotropic structure, which can reversibly construct conductive network and tune heterogeneous interface during cyclic stretching. This film can withstand up to 600% tensile strain and shows stretching-enhanced electrical conductivity. Its EM interference shielding effectiveness (SE) significantly increases with stretching, and the relative SE change (Delta SE/SE0) shows a linear response to the tensile strain. The specific shielding effectiveness (an ultrahigh value of 404 dB mm-1 at 400% strain) and strain sensitivity of the film outperform other stretchable EM functional materials. More interestingly, this film exhibits rapid switching between EM wave transmission and shielding through continuous stretching, which enables an off/on switchable EM interference shielding function. Furthermore, it can be used in a wearable EM sensor to wirelessly monitor human movements by recording changes of EM wave intensity.
查看更多>>摘要：The large-scale application of triboelectric nanogenerator (TENG) based self-powered devices holds promise for cancer treatment for millions of new cancer patients each year. TENG based sensors are capable of collecting patient data over a long time and provide precise cancer data sources for artificial intelligent process. TENG based devices possess great potential for targeted drug therapy, photodynamic therapy and electric field therapy on the tumor area based on the results of artificial intelligence analysis. This review summarizes and discusses the capabilities and prospects of TENG in cancer treatment, recovery, management, prevention and diagnosis. Cancer treatment and diagnosis are currently popular areas where TENGs with artificial intelligence has been applied in precision cancer research. TENGs with artificial intelligence based systems will be a potential candidate for applications in the field of cancer management and prevention.
查看更多>>摘要：Recently, pressure/strain sensor based on triboelectric nanogenerator (TENG) has gained great attentions for monitoring daily health status and robotic research fields, because of their simple device structures and self powered feature. However, higher sensitivity and stretchability are still demanded for satisfying the practical applications. In this work, a self-powered pressure and strain sensor was achieved by utilizing crumpled MXene film as the single-electrode mode TENG. Benefiting from the reconfigurable behavior of the crumpled structure, the MXene TENG showed a maximum areal strain and linear tensile ratio of 2150% and 400%, respectively. Meanwhile, because of the enlarged contact area between triboelectric layers, the output power density of the MXene TENG with micro-crumples was highly improved by 36 times. Therefore, the as prepared sensor exhibited excellent sensitivity of 2.35 V kPa(-1) under pressures from 0.3 to 1.0 kPa, which is superior to majority of the reported sensors based on tribo-/piezo-electricity. In addition, the sensor can be easily attached to human joints to capture and collect the complicated movement signals. By combining with Bluetooth transmission technology, wireless real-time monitoring was realized through transmitting human movement signals to a mobile phone App.
NSTL
Elsevier