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In daily life, some traditional interactive modes, such as keyboards and touch pads, still have a strong vitality and practical value.[[179], [571], [573]] Based on different physical transduction mechanisms, these keyboards or touch pads are essentially tactile sensors that transduce the physical touches into electrical signals and map them to corresponding positioning units.[[572], [574]] Converting physical movement into electrical signal is the original intention of TENG, which addresses the power/energy challenges of devices with powerful sensors nowadays.[555] Therefore, the self-powered TENG technology is exactly a good solution for developing a tactile sensor equipped on these devices.[[538], [540], [574], [576], [578]] In these applications, XY matrix scheme greatly reduces the number of channels and is conducive to high resolution wiring layout.[[575], [578]] In this scheme, crosstalk and target sensing resolution are the problems. This could improve the performance of HP-based piezoelectric device for mechanical energy harvesting, design of the photoferroelectric and photopiezoelectric devices, developing hybrid energy harvesters for multi-source energy harvesting, and developing eco-friendly, flexible, and high-performance devices. Early design of such an energy-aware interface (EAI) mainly consists of a voltage detector and a switch.[[506]] Once the voltage across the supercapacitor exceeds the threshold voltage of the voltage detector, the switch will be turned on to connect the wireless sensor system to the supercapacitor. [Extracted from the article]

A self-powered, sliding electrification based quasi-static triboelectric sensor (QS-TES) for detecting angle from rotating motion is reported. This innovative, cost-effective, simply-designed QS-TES has a two-dimensional planar structure, which consists of a rotator coated with four channel coded Cu foil material and a stator with a fluorinated ethylenepropylene film. On the basis of coupling effect between triboelectrification and electrostatic induction, the sensor generates electric output signals in response to mechanical rotating motion of an object mounted with the sensor. The sensor can read and remember the absolute angular position, angular velocity, and acceleration regardless being continuously monitored or segmented monitored. Under the rotation speed of 100 r min−1, the output voltage of the sensor reaches as high as 60 V. Given a relatively low threshold voltage of ±0.5 V for data processing, the robustness of the device is guaranteed. The resolution of the sensor is 22.5° and can be further improved by increasing the number of channels. Triggered by the output voltage signal, the rotating characteristics of the steering wheel can be real-time monitored and mapped by being mounted to QS-TES. This work not only demonstrates a new principle in the field of angular measurement but also greatly expands the applicability of triboelectric nanogenerator as self-powered sensors. [ABSTRACT FROM AUTHOR]

A new membrane-based triboelectric sensor (M-TES) is presented as a self-powered pressure change sensor. It generates a voltage induced by surface triboelectric charges in response to an air pressure change. Extremely high detection resolutions of 0.34 Pa and 0.16 Pa are achieved when the air pressure increases and decreases in a small region away from the ambient standard atmosphere pressure, respectively, indicating an excellent sensitivity. By integrating the M-TES with a signal processing unit, we demonstrate practical applications of the device in sensing footsteps, respirations, and heartbeat, which suggests widespread use of the M-TES in fields of security surveillance, chemical engineering, geography research, environment monitoring, and personal healthcare. [ABSTRACT FROM AUTHOR]

The applications of a single-layer triboelectric nanogenerator (TENG) may be challenged by its lower output current, and a possible solution is to use three-dimensional (3D) integrated multilayered TENGs. However, the most important point is to synchronize the outputs of all the TENGs so that the instantaneous output power can be maximized. Here, a multi-layered stacked TENG is reported as a cost-effective, simple, and robust approach for harvesting ambient vibration energy. With superior synchronization, the 3D-TENG produces a short-circuit current as high as 1.14 mA, and an open-circuit voltage up to 303 V with a remarkable peak power density of 104.6 W m−2. As a direct power source, it is capable of simultaneously lighting up 20 spot lights (0.6 W ea.) as well as a white G16 globe light. Furthermore, compared with the state-of-the-art vibration energy harvesters, the 3D-TENG has an extremely wide working bandwidth up to 36 Hz in low frequency range. In addition, with specific dimensional design, the 3D-TENG is successfully equipped inside a ball with a diameter of 3 inches, using which 32 commercial LEDs are simultaneously lighted up via hand shaking, exhibiting great potential of scavenging the abundant but wasted kinetic energy when people play basketball, football, baseball, and so on. [ABSTRACT FROM AUTHOR]

Triboelectric motion sensors, based on the generation of a voltage across two dissimilar materials sliding across each other as a result of the triboelectric effect, have generated interest due to the relative simplicity of the typical grated device structures and materials required. However, these sensors are often limited by poor spatial and/or temporal resolution of motion due to limitations in achieving the required device feature sizes through conventional lithography or printing techniques. Furthermore, the reliance on metallic components that are relatively straightforward to pattern into fine features limits the possibility to develop transparent sensors. Polymers would allow for transparent devices, but these materials are significantly more difficult to pattern into fine features when compared to metals. Here, an aerosol‐jet printing (AJP) technique is used to develop triboelectric sensors using a wide variety of materials, including polymers, which can be directly printed into finely featured grated structures for enhanced sensitivity to displacement and speed of motion. A detailed investigation is presented highlighting the role of material selection and feature size in determining the overall resolution of the resulting motion sensor. A three‐channel rotary sensor is also presented, demonstrating the versatility of the AJP technique in developing more complex triboelectric motion sensors. Aerosol‐jet printing is used to develop triboelectric motion sensors, based on the generation of a voltage across two dissimilar materials sliding across each other as a result of the triboelectric effect. A wide variety of materials, including polymers, can be directly printed into fine‐featured grated structures for enhanced sensitivity to displacement and speed of motion. [ABSTRACT FROM AUTHOR]

This article describes a simple, cost-effective, andscalable approachto fabricate a triboelectric nanogenerator (NG) with ultrahigh electricoutput. Triggered by commonly available ambient mechanical energysuch as human footfalls, a NG with size smaller than a human palmcan generate maximum short-circuit current of 2 mA, delivering instantaneouspower output of 1.2 W to external load. The power output correspondsto an area power density of 313 W/m2and a volume powerdensity of 54 268 W/m3at an open-circuit voltageof ∼1200 V. An energy conversion efficiency of 14.9% has beenachieved. The power was capable of instantaneously lighting up asmany as 600 multicolor commercial LED bulbs. The record high poweroutput for the NG is attributed to optimized structure, proper materialsselection and nanoscale surface modification. This work demonstratedthe practicability of using NG to harvest large-scale mechanical energy,such as footsteps, rolling wheels, wind power, and ocean waves. [ABSTRACT FROM AUTHOR]

By combining contact-mode atomicforce microscopy (AFM) and scanningKevin probe microscopy (SKPM), we demonstrated an in situ method forquantitative characterization of the triboelectrification processat the nanoscale. We systematically characterized the triboelectriccharge distribution, multifriction effect on charge transfer, as wellas subsequent charge diffusion on the dielectric surface: (i) theSiO2surface can be either positively or negatively chargedthrough triboelectric process using Si-based AFM probes with and withoutPt coating, respectively; (ii) the triboelectric charges accumulatedfrom multifriction and eventually reached to saturated concentrationsof (−150 ± 8) μC/m2and (105 ± 6)μC/m2, respectively; (iii) the charge diffusion coefficientson SiO2surface were measured to be (1.10 ± 0.03)× 10–15m2/s for the positive chargeand (0.19 ± 0.01) × 10–15m2/s for the negative charges. These quantifications will facilitatea fundamental understanding about the triboelectric and de-electrificationprocess, which is important for designing high performance triboelectricnanogenerators. In addition, we demonstrated a technique for nanopatterningof surface charges without assistance of external electric field,which has a promising potential application for directed self-assemblyof charged nanostructures for nanoelectronic devices. [ABSTRACT FROM AUTHOR]

We introduce an innovative designof a disk triboelectric nanogenerator(TENG) with segmental structures for harvesting rotational mechanicalenergy. Based on a cyclic in-plane charge separation between the segmentsthat have distinct triboelectric polarities, the disk TENG generateselectricity with unique characteristics, which have been studied byconjunction of experimental results with finite element calculations.The role played by the segmentation number is studied for maximizingoutput. A distinct relationship between the rotation speed and theelectrical output has been thoroughly investigated, which not onlyshows power enhancement at high speed but also illuminates its potentialapplication as a self-powered angular speed sensor. Owing to the nonintermittentand ultrafast rotation-induced charge transfer, the disk TENG hasbeen demonstrated as an efficient power source for instantaneouslyor even continuously driving electronic devices and/or charging anenergy storage unit. This work presents a novel working mode of TENGsand opens up many potential applications of nanogenerators for harvestingeven large-scale energy. [ABSTRACT FROM AUTHOR]

Aiming at harvesting ambient mechanicalenergy for self-poweredsystems, triboelectric nanogenerators (TENGs) have been recently developedas a highly efficient, cost-effective and robust approach to generateelectricity from mechanical movements and vibrations on the basisof the coupling between triboelectrification and electrostatic induction.However, all of the previously demonstrated TENGs are based on verticalseparation of triboelectric-charged planes, which requires sophisticateddevice structures to ensure enough resilience for the charge separation,otherwise there is no output current. In this paper, we demonstrateda newly designed TENG based on an in-plane charge separation processusing the relative sliding between two contacting surfaces. UsingPolyamide 6,6 (Nylon) and polytetrafluoroethylene (PTFE) films withsurface etched nanowires, the two polymers at the opposite ends ofthe triboelectric series, the newly invented TENG produces an open-circuitvoltage up to ∼1300 V and a short-circuit current density of4.1 mA/m2with a peak power density of 5.3 W/m2, which can be used as a direct power source for instantaneouslydriving hundreds of serially connected light-emitting diodes (LEDs).The working principle and the relationships between electrical outputsand the sliding motion are fully elaborated and systematically studied,providing a new mode of TENGs with diverse applications. Comparedto the existing vertical-touching based TENGs, this planar-slidingTENG has a high efficiency, easy fabrication, and suitability formany types of mechanical triggering. Furthermore, with the relationshipbetween the electrical output and the sliding motion being calibrated,the sliding-based TENG could potentially be used as a self-powereddisplacement/speed/acceleration sensor. [ABSTRACT FROM AUTHOR]

The triboelectric effect is knownfor many centuries and it isthe cause of many charging phenomena. However, it has not been utilizedfor energy harvesting until very recently.(1-5) Here we developed a new principle of triboelectricgenerator (TEG) based on a fully contacted, sliding electrificationprocess, which lays a fundamentally new mechanism for designing universal,high-performance TEGs to harvest diverse forms of mechanical energyin our daily life. Relative displacement between two sliding surfacesof opposite triboelectric polarities generates uncompensated surfacetriboelectric charges; the corresponding polarization created a voltagedrop that results in a flow of induced electrons between electrodes.Grating of linear rows on the sliding surfaces enables substantialenhancements of total charges, output current, and current frequency.The TEG was demonstrated to be an efficient power source for simultaneouslydriving a number of small electronics. The principle established inthis work can be applied to TEGs of different configurations thataccommodate the needs of harvesting energy and/or sensing from diversemechanical motions, such as contacted sliding, lateral translation,and rotation/rolling. [ABSTRACT FROM AUTHOR]