Smart garments for monitoring physiological and biomechanical signals of the human body are key sensors for personalized healthcare. However, they typically require bulky battery packs or have to be ...plugged into an electric plug in order to operate. Thus, a smart shirt that can extract energy from human body motions to run body-worn healthcare sensors is particularly desirable. Here, we demonstrated a metal-free fiber-based generator (FBG) via a simple, cost-effective method by using commodity cotton threads, a polytetrafluoroethylene aqueous suspension, and carbon nanotubes as source materials. The FBGs can convert biomechanical motions/vibration energy into electricity utilizing the electrostatic effect with an average output power density of ∼0.1 μW/cm2 and have been identified as an effective building element for a power shirt to trigger a wireless body temperature sensor system. Furthermore, the FBG was demonstrated as a self-powered active sensor to quantitatively detect human motion.
Over the past few years, the rapid development of tactile sensing technology has contributed significantly to the realization of intuitional touch control and intelligent human-machine interaction. ...Apart from physical touch or pressure sensing, proximity sensing as a complementary function can extend the detection mode of common single functional tactile sensors. In this work, we present a transparent, matrix-structure dual functional capacitive sensor which integrates the capability of proximity and pressure sensing in one device, and the excellent spatial resolution offered by the isolated response of capacitive pixels enables us to realize precise location identification of approaching objects and loaded pressure with fast response, high stability and high reversibility.
Self‐powered and wearable electronics, which are away from the problems of batteries, can provide the sustainable and comfortable interactive service for people. In this work, cellular polypropylene ...piezoelectret, which is with excellent physical and electrical properties, is utilized to build the human body energy harvesting and self‐powered human health monitoring systems. The cellular polypropylene piezoelectret flexible generator can reach a maximum peak power density of ≈52.8 mW m−2. Simultaneously, self‐powered human body biological signals detecting sensors are demonstrated to detect the human physiological signals, such as coughing action and arterial pulses. This study strongly indicates the great compatibility and potential applications in human healthy monitoring may pave a new developing way for portable and wearable electronics systems.
Simple‐structured and efficient human body energy harvesting and self‐powered human health monitoring systems are demonstrated basing on the cellular polypropylene piezoelectret. A maximum peak power density of ≈52.8 mW m−2 is obtained and human physiological signals, such as coughing action and arterial pulse, are detected. These systems develop a new way for self‐powered and wearable electronics.
Harvest mechanical energy with variable frequency and amplitude in our environment for building self-powered systems is an effective and practically applicable technology to assure the independently ...and sustainable operation of mobile electronics and sensor networks without the use of a battery or at least with extended life time. In this study, we demonstrated a novel and simple arch-shaped flexible triboelectric nanogenerator (TENG) that can efficiently harvesting irregular mechanical energy. The mechanism of the TENG was intensively discussed and illustrated. The instantaneous output power of single TENG device can reach as high as∼4.125mW by a finger typing, which is high enough to instantaneously drive 50 commercial blue LEDs connected in series, demonstrating the potential application of the TENG for self-powered systems and mobile electronics.
Display omitted
► A novel and simple arch-shaped triboelectric nanogenerator is invented that can efficiently used for harvesting irregular mechanical energy. ► Instantaneous output power of single device can reach as high as ∼4.125mW which is enough to instantaneously drive 50 commercial blue LEDs connected in series. ► By conjunction with a transformer, the device can power the wireless infrared sensor system.
By virtue of their high conversion efficiency, simple fabrication process and low cost, flexible generators that can convert ambient mechanical energy into electricity are playing a critical role in ...promoting the development of self-powered wearable electronics. However, urgent challenges have to be overcome to withstand harsh environments, in which the output power performance of all those generators without suitable packaging will deteriorate permanently. Herein, we develop a novel laminated cellular electret film that allows the surface charges to self-recover under ambient air conditions after exposure to an extremely moist atmosphere. The laminated electret cellular film-based flexible generator with sandwich structure can effectively harvest energy from walking motion. Furthermore, this device shows great capability for self-recovery even after operating in extremely moist conditions, an inevitable environment for wearable power supplies. Besides offering valuable new insights, this study opens up new perspectives for low-cost and reliable wearable devices.
Flexible all‐solid‐state asymmetric supercapacitors (ASCs) are fabricated from a novel anode – WO3–x/MoO3–x core/shell nanowires on carbon fabric – and a polyaniline cathode (figure). In addition to ...the high electrochemical performance of the devices, other characteristics, such as low toxicity, flexibility, environmental compatibility, light weight, and low requirements for packaging, make the all‐solid‐state ASCs potential candidates for applications in energy storage, flexible electronics, and other consumer electronics.
Recently, many attempts have been made to increase the specific capacitance of carbon nanotubes (CNTs). Chemical enhancement by adding redox active functional groups on CNTs increases the specific ...capacitance, while excessive oxidation decreases conductivity and leads to poor cycle life. Here we report the electrochemical enhancement methods followed by annealing at different temperatures in air to add and adjust the redox active functional groups on freestanding CNT films. Functionalized freestanding CNT films were used as positive electrodes, assembled with freestanding CNT/MoO3−x negative electrodes to fabricate carbon nanotube-based solid-state asymmetric supercapacitors (ASCs). The whole device showed a high volumetric capacitance of 3.0Fcm−3, energy and power density of 1.5mWhcm−3 and 4.2Wcm−3, respectively. We also fabricated a SCs pack to drive a homemade wireless transport system successfully, demonstrating the potential applications of this solid-state system for portable/wearable electronics.
Electrochemical methods followed by annealing to adjust the functional groups were used on freestanding CNT films. Solid-state asymmetric supercapacitors were fabricated by assembling functionalized CNT films with CNT/MoO3−x electrodes. The device showed a volumetric capacitance of 3.0Fcm−3, energy and power density of 1.5mWhcm−3 and 4.2Wcm−3. We also fabricated a SCs pack to drive a homemade wireless transport system, demonstrating the potential for portable electronics. Display omitted
•Electrochemical methods followed by annealing to adjust functional groups on CNT.•Solid-state ASCs were fabricated with functionalized CNT and CNT/MoO3−x electrodes.•The device showed high energy and power density of 1.5mWhcm−3 and 4.2Wcm−3.•A SCs pack was applied to drive a home-made wireless transport system.
The cellular piezoelectret generator (CPG) has drawn considerable attention as an emerging flexible energy harvester because of its advantages of a simple structure, easy assembly, a low cost, and ...eco‐friendliness. To facilitate practical applications, an initial theoretical study of CPGs is presented in this work, in which the output characteristics of CPGs can be optimized through an appropriate choice of parameters, including the electret dielectric permittivity, device structure, polarization process, and external load. A good agreement with experimental results is achieved, verifying the validity of the theoretical study. The reported theory offers a complete interpretation of the dynamic working mechanism of CPGs and provides significant guidance for the design of a CPG with enhanced yield.
A theoretical study of cellular piezoelectret generators (CPGs) is presented, focusing on the enhancement of their dynamic performance. An effective means to optimize the output characteristics of CPGs is found. This discovery will enhance performance and application range of future devices.
Metasurface holograms, with the capability to manipulate spatial light amplitudes and phases, are considered next-generation solutions for holographic imaging. However, conventional fabrication ...approaches for meta-atoms are heavily dependent on electron-beam lithography (EBL), a technique known for its expensive and time-consuming nature. In this paper, a polarization-insensitive metasurface hologram is proposed using a cost-effective and rapid nanoimprinting method with titanium dioxide (TiO2) nanoparticle loaded polymer (NLP). Based on a simulation, it has been found that, despite a reduction in the aspect ratio of meta-atoms of nearly 20%, which is beneficial to silicon master etching, NLP filling, and the mold release processes, imaging efficiency can go up to 54% at wavelength of 532 nm. In addition, it demonstrates acceptable imaging quality at wavelengths of 473 and 671 nm. Moreover, the influence of fabrication errors and nanoimprinting material degradation in terms of residual layer thickness, meta-atom loss or fracture, thermal-induced dimensional variation, non-uniform distribution of TiO2 particles, etc., on the performance is investigated. The simulation results indicate that the proposed device exhibits a high tolerance to these defects, proving its applicability and robustness in practice.
A metasurface is a layer of subwavelength-scale nanostructures that can be used to design functional devices in ultrathin form. Various metasurface-based optical devices – coined as flat optics ...devices – have been realized with distinction performances in research laboratories using electron beam lithography. To make such devices mass producible at low cost, metasurfaces over a large area have also been defined with lithography steppers and scanners, which are commonly used in semiconductor foundries. This work reviews the metasurface process platforms and functional devices fabricated using complementary metal-oxide-semiconductor-compatible mass manufacturing technologies. Taking both fine critical dimension and mass production into account, the platforms developed at the Institute of Microelectronics (IME), A*STAR using advanced 12-inch immersion lithography have been presented with details, including process flow and demonstrated optical functionalities. These developed platforms aim to drive the flat optics from lab to fab.
PDF