A paper‐based active tactile sensor array (PATSA) with a dynamic sensitivity of 0.35 V N−1 is demonstrated. The pixel position of the PATSA can be routed by analyzing the real‐time recording ...voltages in the pressing process. The PATSA performance, which remains functional when removing partial areas, reveals that the device has a potential application to customized electronic skins.
Energy storage on paper: Paper‐based, all‐solid‐state, and flexible supercapacitors were fabricated, which can be charged by a piezoelectric generator or solar cells and then discharged to power a ...strain sensor or a blue‐light‐emitting diode, demonstrating its efficient energy management in self‐powered nanosystems (see picture).
Submarine communication and geologic examination in deep earth are challenging because high-frequency electromagnetic (EM) waves with short wavelength can be blocked by soil and seawater, as a ...result, the low-frequency (LF) waves are preferred in these applications. However, the conventional LF transmitter facility requires size on the scale of the wavelength (here, >1 km), making portable transmitters extremely challenging. To greatly decrease the size of the conventional LF communication system, this article introduces a novel LF transmitter based on electret, which applies mechanical motion to accelerate the charges on the polymer electret and realize the high-efficiency generation of EM fields. Moreover, a magnetic field analytical model is established to analyze the influence of structure parameters, shapes, rotation frequency, and stacking mode on the EM signals' generation and propagation, in terms of not only distance but also orientation. Finally, an electret-based mechanically actuated transmitter prototype is built to verify the correctness and feasibility of the design.
Stable and repeatable operation is paramount for practical and extensive applications of all energy harvesters. Herein, we develop a new type of flexible piezoelectret generator, which converts ...mechanical energy into electricity consistently even under harsh environments. Specifically, the generator, with piezoelectric coefficient (d33) reaching ~ 6300 pC/N, had worked stably for continuous ~ 90000 cycles, and the generator pressed by a human hand produced load peak current and power up to ~ 29.6 μA and ~ 0.444mW, respectively. Moreover, the capability to steadily produce electrical power under extreme moisture and temperature up to 70°C had been achieved for possible applications in wearable devices and flexible electronics.
•A new type of flexible piezoelectret generator with piezoelectric coefficient (d33) coefficient reaching ~ 6300 pC/N is fabricated for mechanical energy harvesting.
•Load peak current and corresponding peak power of ~ 29.6 μA and ~ 0.444mW are reached by hand pressing the generator, and stable outputs are achieved for ~ 90000 continuous working cycles.
•The generator had remarkable output stability under harsh environments with extreme moisture and temperature up to 70°C, indicating the feasibility for wearable energy harvesting. Display omitted
Flexible piezoelectret generator with piezoelectric coefficient (d33) reaching ~ 6300pC/N is used to harvest mechanical energy in harsh environments.
•The piezoelectric coefficient of this flexible piezoelectret generator reached ~ 6300pC/N.•The generator generated peak power of ~ 0.444mW and worked steadily for ~ 90000 cycles.•The generator worked steadily under extreme moisture and temperature up to 70°C.
Abstract Bidirectional haptic communication devices accelerate the revolution of virtual/augmented reality and flexible/wearable electronics. As an emerging kind of flexible piezoelectric materials, ...piezoelectret materials can effortlessly convert mechanical force into electrical signals and respond to electrical fields in a deformation manner, exhibiting enormous potential in the construction of bidirectional haptic communication devices. Existing reviews on piezoelectret materials primarily focus on flexible energy harvesters and sensors, and the recent development of piezoelectret‐based bidirectional haptic communication devices has not been comprehensively reviewed. Herein, a comprehensive overview of the materials construction, along with the recent advances in bidirectional haptic communication devices, is provided. First, the development timeline, key characteristics, and various fabrication methods of piezoelectret materials are introduced. Subsequently, following the underlying mechanisms of bidirectional electromechanical signal conversion of piezoelectret, strategies to improve the d 33 coefficients of materials are proposed. The principles of haptic perception and feedback are also highlighted, and representative works and progress in this area are summarized. Finally, the challenges and opportunities associated with improving the overall practicability of piezoelectret materials‐based bidirectional haptic communication devices are discussed.
Flexible and wearable pressure sensors are of essential importance in developing artificial electronic skin (e-skin) for areas such as healthcare monitoring and clinical diagnosis. Here, we report an ...ultrasensitive cellular fluorocarbon piezoelectret pressure sensor (FPS) via a three-step hot-pressing method. By constructing micron-sized voids in the inner cell, and combination with outstanding charge storage ability of the fluorocarbon electrets, tremendous piezoelectric activity can be obtained. The flexible FPS showed advantages of remarkable sensitivity (7380pCN−1) in the subtle-pressure regime (<1kPa), fast response time (50ms), very low limit of detection (5Pa) as well as high stability (30,000 cycles). In addition, the flexible and self-powered FPS owns the capability for detecting human motions such as wrist stretching, cheek motion from open-bite-open, eyes blinking and chest respiration, respectively. It can be also used for monitoring human physiological signals such as radial artery pulse wave. By virtue of easy processability in large scale, light weight, and low cost, the FPS is especially suitable for mass production and flexible electronics, indicating their promising applications in artificial intelligence and mobile healthcare monitoring systems.
An ultrasensitive cellular fluorocarbon piezoelectret pressure sensor (FPS) was fabricated via a simple three-step hot-pressing method. The FPS has achieved an extremely high pressure sensitivity of 7380pCN−1 in subtle-pressure regime, and can be used in continuously real-time monitoring human motions and radial artery pulse, which indicates its potential applications in wearable healthcare monitoring and clinical diagnosis. Display omitted
•The cellular fluorocarbon piezoelectret pressure sensor (FPS) via a simple three-step hot-pressing method is developed.•The FPS showed advantages of remarkable sensitivity (7380pCN−1), fast response time (50ms), low limit of detection (5Pa) as well as high stability (30,000 cycles).•The FPS owns the capability for detecting human physiological signals such as radial artery pulse wave.
Exploring flexible tactile sensors capable of recognizing surface information is significant for the development of virtual reality, artificial intelligence, soft robotics, and human–machine ...interactions (HMI). However, it is still a challenge for current tactile sensors to efficiently recognize the surface pattern information while maintaining the simplicity of the overall system. In this study, cantilever beam-like magnetized micropillars (MMPs) with height gradients are assembled as a position-registered array for rapid recognition of surface pattern information. After crossing the surface location with convex patterns, the deformed MMPs undergo an intrinsic oscillating process to induce damped electrical signals, which can then be converted to a frequency domain for eigenfrequency extraction. Via precisely defining the specific eigenfrequencies of different MMPs, position mapping is realized in crosstalk-free behavior even though all signals are processed by one communication channel and a pair of electrodes. With a customized LabVIEW program, the surface information (e.g., letters, numbers, and Braille) can be accurately reconstructed by the frequency sequence produced in a single scanning procedure. We expect that the proposed interface can be a convenient and powerful platform for intelligent surface information perception and an HMI system in the future.
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•a high yield manufacturing process based on laser induced graphite.•highly sensitive devices using serpentine electrode design.•highly dynamic responses to mimic the human skins in ...the range of 5–400 Hz.•conformable attachment for human machine interface demonstrations.
Stretchable strain sensors are important elements in flexible and skin-mountable electronics typically fabricated using semiconductor materials in cleanroom-based manufacturing processes. This work demonstrates piezoresistive strain sensors with both strain and pressure sensing capabilities by a cost-effective and versatile process utilizing a laser patterning, graphite conversion, and polymeric transfer process. The resulting sensing systems exhibit high gauge factor of 37 and pressure sensitivity of 0.088kPa-1 with high sustainable strain up to 70%. These exceptional performances are explained and observed by deforming the sensor under an in-situ SEM to show self-healing characteristics of films under large deformations. The highly sensitive strain sensors have been shown in human interface demonstrations, such as measuring the physiological signal of the human pulses, finger pressure and bending of fingers as well as assisting a robotic arm for gripping and releasing operations.
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