基于拱形结构的摩擦-压电复合式能量采集器

随着纳米技术和加工工艺的发展,纳米发电机被提出用于将自然界中微弱低频振动机械能转化为电能,进而为小型传感系统长续航工作提供可能.基于摩擦纳米发电机和压电纳米发电机的电荷积累与转移规律,设计了拱形结构并构建了摩擦-压电复合式能量采集器,将两种力-电转换模式有效整合,并突破了以往能量采集器只能收集垂直方向机械能的限制.搭建...     

Triboelectric and Piezoelectric Effects in a Combined Tribo‐Piezoelectric Nanogenerator Based on an Interfacial ZnO Nanostructure

In this contribution, combined triboelectric and piezoelectric generators (TPEG) with a sandwich structure of aluminum‐polydimethylsiloxane/polyvinylidene fluoride composite‐carbon (Al‐PPCF‐Carbon) are fabricated for the purpose of mechanical energy harvesting. Improved by the surface modification of PPCF with zinc oxide (ZnO) nanorods through a hydrothermal method, the TPEG generates an open‐circuit voltage (V_oc) of ≈40 V, a short‐circuit current (I_sc) of 0.28 μA with maximum power density of ≈70 mWm^?2_, and maximum conversion efficiency of 34.56%. Subsequently, in order to understand the transduction mechanism of the triboelectric and piezoelectric effects, analyses focusing on the potential composition ratio in the final output and the impact of ZnO interfacial nanostructure are carried out. The observed potential ratio between triboelectric and piezoelectric effects is 12.75:1 and the highest potential improvement by ZnO nanorods of 21.8 V is achieved by the TPEG fabricated with spacer. Finally, the relationships between the voltage, power density, conversion efficiency, and the external load resistances are also discussed. Overall, the fabricated TPEG is proved to be a simple and effective nanogenerator in mechanical energy conversion with enhanced output potential and conversion efficiency.     

Characterization of various stress-induced oxide traps in MOSFET'sby using a subthreshold transient current technique

An oxide trap characterization technique by measuring a subthreshold current transient is developed. This technique consists of two alternating phases, an oxide charge detrapping phase and a subthreshold current measurement phase. An analytical model relating a subthreshold current transient to oxide charge tunnel detrapping is derived. By taking advantage of a large difference between interface trap and oxide trap time-constants, this transient technique allows the characterization of oxide traps separately in the presence of interface traps. Oxide traps created by three different stress methods, channel Fowler-Nordheim (F-N) stress, hot electron stress and hot hole stress, are characterized. By varying the gate bias in the detrapping phase and the drain bias in the measurement phase, the field dependence of oxide charge detrapping and the spatial distribution of oxide traps in the channel direction can be obtained. Our results show that 1) the subthreshold current transient follows a power-law time-dependence at a small charge detrapping field, 2) while the hot hole stress generated oxide traps have a largest density, their spatial distribution in the channel is narrowest as compared to the other two stresses, and 3) the hot hole stress created oxide charges exhibit a shortest effective detrapping time-constant     

Stretchable,Washable, and Ultrathin Triboelectric Nanogenerators as Skin-Like Highly Sensitive Self-Powered Haptic Sensors

Accompanying the boom in multifunctional wearable electronics, flexible, sustainable, and wearable power sources are facing great challenges. Here, a stretchable, washable, and ultrathin skin-inspired triboelectric nanogenerator (SI-TENG) to harvest human motion energy and act as a highly sensitive self-powered haptic sensor is reported. With the optimized material selections and structure design, the SI-TENG is bestowed with some merits, such as stretchability ( ≈ 800%), ultrathin ( ≈ 89 µ m), and light-weight ( ≈ 0.23 g), which conformally attach on human skin without disturbing its contact. A stretchable composite electrode, which is formed by homogenously intertwining silver nanowires (AgNWs) with thermoplastic polyurethane (TPU) nanofiber networks, is fabricated through synchronous electrospinning of TPU and electrospraying of AgNWs. Based on the triboelectrification effect, the open-circuit voltage, short-circuit current, and power density of the SI-TENG with a contact area of 2 × 2 cm² and an applied force of 8 N can reach 95 V, 0.3 µ A, and 6 mW m⁻², respectively. By integrating the signal-processing circuits, the SI-TENG with excellent energy harvesting and self-powered sensing capability is demonstrated as a haptic sensor array to detect human actions. The SI-TENG exhibits extensive applications in the fields of human–machine interface and security systems.     

Autonomously Adhesive,Stretchable, and Transparent Solid-State Polyionic Triboelectric Patch for Wearable Power Source and Tactile Sensor

Robust power supplies and self-powered sensors that are extensible, autonomously adhesive, and transparent are highly desirable for next-generation electronic/energy/robotic applications. In the work, a solid-state triboelectric patch integrated with the above features ( ≈ 318% elongation, > 85% average transmission, ≈ 44.3 N m⁻¹ adhesive strength) is developed using polyethylene oxide/waterborne polyurethane/phytic acid composite (abbreviated as PWP composite) as an effective current collector and silicone rubber as tribolayer. The PWP composite is optimized systematically and corresponding single-electrode device can supply a power density of 2.3 W m⁻² at 75% strain. The triboelectric patch is capable of charging capacitors and powering electronics by efficiently harvesting biomechanical energies. Moreover, it can be autonomously attached to nonplanar skin or apparel substrates and used as a tactile sensor or an epidermal input touchpad for physiological motion detection and remote control of appliances, respectively. Even after dynamic deformation, tailoring, and prolonged use, the patch can maintain good stability and reliability of electrical outputs. This work provides a novel solid-state and liquid-free polyionic electrode-based triboelectric nanogenerator integrated with adhesiveness, stretchability, and transparency, which can meet wide application needs from transparent electronics, artificial skins, to smart interfaces.     

Tribotronic Phototransistor for Enhanced Photodetection and Hybrid Energy Harvesting

Tribotronics is a new field developed by coupling triboelectricity and semiconductor, which can drive triboelectric‐charge‐controlled optoelectronic devices by further introducing optoelectronics. In this paper, a tribotronic phototransistor (TPT) is proposed by coupling a field‐effect phototransistor and a triboelectric nanogenerator (TENG), in which the contact‐induced inner gate voltage by the mobile frictional layer is used for modulating the photodetection characteristics of the TPT. Based on the TPT, alternatively, a coupled energy‐harvester (CEH) is fabricated for simultaneously scavenging solar and wind energies, in which the output voltage on the external resistance from the wind driven TENG is used as the gate voltage of the TPT for enhancing the solar energy conversion. As the wind speed increases, the photovoltaic characteristics of the CEH including the short‐circuit current, open‐circuit voltage, and maximal output power have been greatly enhanced. This work has greatly expanded the functionality of tribotronics in photodetection and energy harvesting, and provided a potential solution for highly efficient harvesting and utilizing multitype energy.     

Investigation of oxide charge trapping and detrapping in a MOSFETby using a GIDL current technique

We proposed a new measurement technique to investigate oxide charge trapping and detrapping in a hot carrier stressed n-MOSFET by measuring a GIDL current transient. This measurement technique is based on the concept that in a MOSFET the Si surface field and thus GIDL current vary with oxide trapped charge. By monitoring the temporal evolution of GIDL current, the oxide charge trapping/detrapping characteristics can be obtained. An analytical model accounting for the time-dependence of an oxide charge detrapping induced GIDL current transient was derived. A specially designed measurement consisting of oxide trap creation, oxide trap filling with electrons or holes and oxide charge detrapping was performed. Two hot carrier stress methods, channel hot electron injection and band-to-band tunneling induced hot hole injection, were employed in this work. Both electron detrapping and hole detrapping induced GIDL current transients mere observed in the same device. The time-dependence of the transients indicates that oxide charge detrapping is mainly achieved via field enhanced tunneling. In addition, we used this technique to characterize oxide trap growth in the two hot carrier stress conditions. The result reveals that the hot hole stress is about 10⁴ times more efficient in trap generation than the hot electron stress in terms of injected charge     

Recent Progress in Power Generation from Water/Liquid Droplet Interaction with Solid Surfaces

Water covers ≈70% of the Earth's surface and it contains a tremendous amount of energy that remains unexploited. With the advance of nanotechnology, new strategies toward harnessing water energy based on new mechanisms are proposed. Here, the interaction mechanisms between a water droplet and a solid surface for harvesting energy, including water–solid contact electrification in the four basic working modes of a triboelectric nanogenerator and streaming current, are reviewed. Among them, nanogenerators based on the contact electrification show the highest output. Practical applications are also presented, such as sensing application, wearable power generation, all‐weather power generation, and blue energy solutions. At last, perspectives and opportunities for using water/liquid‐based energy are discussed.     

Metal Micropatterning by Triboelectric Spark Discharge

Metal micropatterns play critical roles in flexible electronics. However, the lack of versatile strategies for micropatterning of diverse metal materials on various thin, flexible or stretchable substrates has limited the rapid development of flexible electronics. Here, a metal micropatterning method by triboelectric spark discharge under atmospheric environment is developed, where a triboelectric nanogenerator (TENG) is employed to precisely and safely control the voltage, current, and frequency of the spark discharges. Micropatterns of metal films like gold, silver, copper, aluminum and platinum are successfully fabricated on substrates of polyimide, polyethylene terephthalate, polyvinyl chloride, polydimethylsiloxane, paper or latex, even on ultrathin substrates (5 μm thick) without damage, where the feature sizes of metal patterns are controllable from 20 μm to 1 mm. Experimental insights into the triboelectric spark discharge behaviors and the pattern feature sizes control are discussed. A straightforward fabrication of metal patterns on the balloon surface or human skin through “handwriting” by a pencil as discharge electrode is realized. Besides metals, extended processibility of conductive materials like carbon nanotubes, graphene, MXene, graphite, carbon fibers, and conductive polymers are also demonstrated. This work proves the possibility of microfabrication by TENG, which is of simplicity and attractiveness for flexible electronics.     

Self‐Powered Vehicle Emission Testing System Based on Coupling of Triboelectric and Chemoresistive Effects

Traditional triboelectric nanogenerator (TENG)‐based self‐powered chemical‐sensing systems are demonstrated by measuring the triboelectric effect of the sensing materials altered by the external stimulus. However, the limitations of triboelectric sensing materials and instable outputs caused by ambient environment significantly restrict their practical applications. In this work, a stable and reliable self‐powered chemical‐sensing system is proposed by coupling triboelectric effect and chemoresistive effect. The whole system is constructed as the demo of a self‐powered vehicle emission test system by connecting a vertical contact–separate mode TENG as energy harvester with a series‐connection resistance‐type gas sensor as exhaust detector and the parallel‐connection commercial light‐emitting diodes (LEDs) as alarm. The output voltage of TENG varies with the variable working states of the gas sensor and then directly reflects on the on/off status of the LEDs. The working mechanism can be ascribed to the specific output characteristics of the TENG tuned by the load resistance of the gas sensor, which is responded to the gas environment. This self‐powered sensing system is not affected by working frequency and requires no external power supply, which is favorable to improve the stability and reliability for practical application.     

Microplasma‐Discharge‐Based Nitrogen Fixation Driven by Triboelectric Nanogenerator toward Self‐Powered Mechano‐Nitrogenous Fertilizer Supplier

Development of novel nitrogen fixation technology is realistically significant for the fertilizer industry and agriculture. Traditional plasma‐induced nitrogen fixation technology is severely limited in some instances because this route generally requires a continuous power input with the features of complicated apparatus fabrication, high cost, nonportability, etc. Herein, a triboelectric nanogenerator (TENG)‐driven microplasma discharge–based nitrogen fixation system is conceived by integrating a high‐voltage output TENG and a discharge reactor. The novel TENG has the capability to generate a high voltage of about 1300 V without additional auxiliary. The generated voltage can induce microplasma discharge under atmospheric environment in the discharge reactor, where nitrogen gas is successfully converted into nitrogen dioxide and nitric acid, and atmospheric nitrogen fixation is therefore realized. The TENG‐driven microplasma discharge‐based nitrogen fixation system can serve as a nitrogenous fertilizer supplier, and correspondingly, NaNO₃ fertilizer is produced via driving the system by human walking stimuli for crop cultivation. A promising and energy‐saving atmospheric nitrogen fixation strategy with environmental friendliness, flexible operation, and high safety is offered.     

A novel interface circuit for triboelectric nanogenerator

For most triboelectric nanogenerators (TENGs), the electric output should be a short AC pulse, which has the common characteristic of high voltage but low current. Thus it is necessary to convert the AC to DC and store the electric energy before driving conventional electronics. The traditional AC voltage regulator circuit which commonly consists of transformer, rectifier bridge, filter capacitor, and voltage regulator diode is not suitable for the TENG because the transformer''s consumption of power is appreciable if the TENG output is small. This article describes an innovative design of an interface circuit for a triboelectric nanogenerator that is transformerless and easily integrated. The circuit consists of large-capacity electrolytic capacitors that can realize to intermittently charge lithium-ion batteries and the control section contains the charging chip, the rectifying circuit, a comparator chip and switch chip. More important, the whole interface circuit is completely self-powered and self-controlled. Meanwhile, the chip is widely used in the circuit, so it is convenient to integrate into PCB. In short, this work presents a novel interface circuit for TENGs and makes progress to the practical application and industrialization of nanogenerators.     

Self‐Recovering Triboelectric Nanogenerator as Active Multifunctional Sensors

A novel self‐recovering triboelectric nanogenerator (STENG) driven by airflow is designed as active multifunctional sensors. A spring is assembled into the STENG and enables the nanogenerator to have self‐recovering characteristic. The maximum output voltage and current of the STENG is about 251 V and 56 μA, respectively, corresponding to an output power of 3.1 mW. The STENG can act as an active multifunctional sensors that includes a humidity sensor, airflow rate sensor, and motion sensor. The STENG‐based humidity sensor has a wide detection range of 20%–100%, rapid response time of 18 ms, and recovery time of 80 ms. Besides, the STENG could be utilized in the application of security monitoring. This work expands practical applications of triboelectric nanogenerators as active sensors with advantages of simple fabrication and low cost.     

MoS2 Tribotronic Transistor for Smart Tactile Switch

A novel tribotronic transistor has been developed by vertically coupling a single‐electrode mode triboelectric nanogenerator and a MoS₂ field effect transistor. Once an external material contacts with or separates from the device, negative charges are induced by triboelectrification on the surface of the polymer frictional layer, which act as a “gate” voltage to modulate the carrier transport in the MoS₂ channel instead of the conventional applied gate voltage; the drain‐source current can be tuned in the range of 1.56–15.74 μA, for nearly ten times. The application of this MoS₂ tribotronic transistor for the active smart tactile switch is also demonstrated, in which the on/off ratio can reach as high as ≈16 when a finger touches the device and the increased drain‐source current is sufficient to light two light‐emitting diodes. This work may provide a technique route to utilize the 2D materials based tribotronic transistors in MEMS, nanorobotics, and human–machine interfacing.     

Refreshable Braille Display System Based on Triboelectric Nanogenerator and Dielectric Elastomer

The blind mainly relies on Braille books to obtain text information. However, Braille books with invariable content are ponderous and inconvenient to read. Hence, it is essential to find a safe, simple and effective method to develop new Braille devices. This advanced method promises to be the next generation Braille book that is refreshable, flexible, and portable. Therefore, a safe dielectric elastomer Braille device actuated by a triboelectric nanogenerator is designed. It is easy to fabricate, inexpensive, and safe without any potential hazard for blind people. For triboelectric nanogenerators, the friction between two thin films can generate a voltage over 3 kV with a current of just 2 µA to deliver a shape change of the dielectric elastomer membrane. In the meantime, with the support of the pressor air in the chamber, the membrane will be raised up to be a touchable Braille dot. In addition, a programmed switch matrix is designed to control the Braille device with multiple dielectric elastomer dots to realize complicated refreshable display, providing a possibility of a page-size and portable braille e-book for the blind in the near future.     

On the influence of the variation of measurement conditions on the FNT characteristics of stressed thin silicon oxides

We have investigated the influence of the Fowler–Nordheim-tunneling (FNT) measurement conditions on current voltage characteristics of stressed thin oxides. In the pre-tunneling voltage range we have studied the influence of stress condition, measurement time of the measurement equipment, sweep direction and voltage-step height of the voltage ramp. An influence of the transient and stationary stress induced leakage current on the FN current voltage characteristic could be observed, which can be explained by the trapping and detrapping of electrons using a simple energy band diagram.     

Acid and Alkali-Resistant Textile Triboelectric Nanogenerator as a Smart Protective Suit for Liquid Energy Harvesting and Self-Powered Monitoring in High-Risk Environments

Industrialization and anthropogenic activities are expected and unavoidable to consummate the current resources of humankind, which also lead to accidents in the laboratory, chemical plants, or other high risk areas that cause severe burns, or even casualties. Increased casualties in such accidents are due to inappropriate safety measures and prevention. Here, a smart anti-chemical protective suit with a bio-motion energy harvesting and self-powered safety monitoring system is demonstrated, which can protect the body from chemical harm, detect sudden chemical spills, monitor human real-time living signals, and trigger alarms in an emergency. Particularly, a fabric triboelectric nanogenerator (F-TENG), which is fabricated by the all-fiber single-electrode triboelectric nanogenerator yarn (SETY), works as the basic elements of the intelligent suit. The SETY with core-shell structured design shows a high sensitivity to the corrosive liquids including acids and alkalis. Furthermore, the working principle of the yarn based nanogenerator that is powered by contacting with acid liquid droplets is demonstrated for the first time. In addition, discretionary thickness, permeability, and any other functionalities are also achieved by taking advantage of the fabric structure. This self-powered smart anti-chemical protective suit equipped with a real time monitoring system will benefit the wearer who works in a very high-risk environment.     

A Swing Self-Regulated Triboelectric Nanogenerator for High-Entropy Ocean Breaking Waves Energy Harvesting

Multidirectional irregular breaking wave is the most prominent feature of the ocean surface and bears tremendous amounts of sustainable high-entropy energy. However, the commercial utilization and harvesting efficiency are very limited low due to its low-frequency and low-amplitude. Here, a swing self-regulated triboelectric nanogenerator (SSR-TENG) is proposed, which can convert collected low-grade breaking waves energy into electrical energy by regulating the oscillation frequency and resonance effect. Benefiting from simple and efficient structural strategy, SSR-TENG outputs a peak power of 0.14 mW under wave height range of 6–11 cm, that the open-circuit voltage, short-circuit current and transferred charge increases is 5.8, 4, and 3.7 times compared to without self-regulated design, respectively. This work gives a practical solution to the problems faced by harvesting high-entropy ocean breaking waves energy, which exhibits large potential for building the self-powered ocean assessment and meteorology system in the future.     

A Nonmetallic Stretchable Nylon‐Modified High Performance Triboelectric Nanogenerator for Energy Harvesting

As a new energy harvesting strategy, triboelectric nanogenerators which have a broad application prospect in collecting environmental energy, human body mechanical energy, and supplying power for low‐power electronic devices, have attracted extensive attention. However, technology challenges still exist in the stretchability for the preparation of some high‐performance triboelectric materials. In this work, a new strategy for nonmetallic nylon‐modified triboelectric nanogenerators (NM‐TENGs) is reported. Nylon is introduced as a high performance friction material to enhance the output performance of the stretchable TENG. The uniform matrix reduces the difficulty of heterogeneous integration and enhances the structural strength. The open‐circuit voltage (V_OC) and short‐circuit current (I_SC) of NM‐TENG can reach up to 1.17 kV and 138 µA, respectively. The instantaneous power density reaches 11.2 W m^?2 and the rectified output can directly light ≈480 LEDs. The transferred charge density is ≈100 µC m^?2 in one cycle when charging the capacitor. In addition, a low‐power electronic clock can be driven directly by the rectified signal without additional circuits. NM‐TENG also has high enough strain rate and can be attached to the human body for energy harvesting effectively. This work provides a new idea for fabrication of stretchable TENGs and demonstrates their potential application.     

Triboelectric Nanogenerator for Harvesting Vibration Energy in Full Space and as Self‐Powered Acceleration Sensor

A spherical three‐dimensional triboelectric nanogenerator (3D‐TENG) with a single electrode is designed, consisting of an outer transparent shell and an inner polyfluoroalkoxy (PFA) ball. Based on the coupling of triboelectric effect and electrostatic effect, the rationally developed 3D‐TENG can effectively scavenge ambient vibration energy in full space by working at a hybridization of both the contact‐separation mode and the sliding mode, resulting in the electron transfer between the Al electrode and the ground. By systematically investigating the output performance of the device vibrating under different frequencies and along different directions, the TENG can deliver a maximal output voltage of 57 V, a maximal output current of 2.3 μA, and a corresponding output power of 128 μW on a load of 100 MΩ, which can be used to directly drive tens of green light‐emitting diodes. Moreover, the TENG is utilized to design the self‐powered acceleration sensor with detection sensitivity of 15.56 V g^‐1. This work opens up many potential applications of single‐electrode based TENGs for ambient vibration energy harvesting techniques in full space and the self‐powered vibration sensor systems.