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Achieving both high sensitivity and wide detecting range is significant for the applications of triboelectric nanogenerator-based self-powered pressure sensors (TPSs). However, most of the previous designs with high sensitivity usually struggle in a narrow pressure detection range (<30 kPa) while expanding the detection range normally sacrifices the sensitivity. To overcome this well-known obstacle, herein, piezopotential enhanced triboelectric effect realized by a rationally designed PDMS/ZnO NWs hierarchical wrinkle structure was exploited to develop a TPS (PETPS) with both high sensitivity and wide detecting range. In this PETPS design, the piezopotential derived from the deformation of ZnO NWs enhances its tribo-charge transferring ability; meanwhile, the hierarchical structure helps to establish a dynamically self-adjustable contact area. Benefiting from these advantages, the PETPS simultaneously achieves high sensitivity (0.26 nC cm–2kPa–1from 1 to 25 kPa, and 0.02 nC cm–2kPa–1from 25 to 476 kPa), fast response (46 ms), wide sensing range (1 to 476 kPa), and good stability (over 4000 cycles). In addition, the output charge density that is independent of the speed rate of driven force was adopted as the sensing signal of PETPS to replace the commonly used peak voltage/current values, enabling it more adaptive to accurately detect pressure variation in real applications.

Triboelectric nanogenerator (TENG) has been widely recognized as an efficient technology for exploiting low-frequency (LF) mechanical energy, but the sparse outputs at low frequencies and insufficient durability at high frequencies hinder its extensive applications. Herein, a robust and high-output triboelectric-electromagnetic hybrid nanogenerator (TEHG) is proposed with an ingenious airflow-based motion conversion mechanism (AMCM) and a well-designed maglev mechanism. Distinct from conventional MCMs generally constructed with complicated rigid components, the AMCM transforms LF-motions to fast rotation through a flexible bladder and air tubes. Enabled by the AMCM, the TENG part can provide power density up to 274 mW/kg at an output frequency 70 times higher than the excitation frequency. The normalized voltage of the TENG part stabilizes at 84.1 % after 8-day durability test with the specially designed maglev mechanism, which allows the TENG part to operate in intermittent (sliding) contact state under slow rotation to replenish tribo-charges with minor material wear whereas switch to non-contact state without material wear under fast rotation. By combining the complementary output characteristics of triboelectric and electromagnetic technologies, a storage capacitor can be charged to a higher voltage level within remarkably reduced time. The practical feasibility of the AMCM-TEHG was verified by arranging it on a footpath to charge a wireless digital camera and a wireless sensing system. This study provides a promising strategy for multiplying the output frequencies as well as increasing the durability of TEHGs for efficiently exploiting LF-mechanical energy.

Wide-band vibration is abundant in various industrial equipment, but extracting low frequency energy is challenging. Here, we demonstrated a trapezoidal cantilever-structure triboelectric nanogenerator (C-TENG) that can efficiently harvest energy from vibration in the range of 1–22 Hz. The C-TENG is fabricated with a flexible film electrode, and its mechanical model is analyzed with structural mechanics for the optimal performance of the device. The C-TENG can harvest the vibration source with a frequency as low as 1 Hz, and its output power density reaches 62.2 W/m3at a vibration frequency of 5 Hz. Furthermore, a power management module is developed, and its integration with TENG arrays enables the self-powered timing and wireless transmitting systems. This work proposes an effective strategy to harvest ubiquitously distributed but usually neglected vibration sources, which would contribute to the development of self-powered electronic systems and Internet of Things.

Deep learning methodologies have revolutionized prediction in many fields and is potential to do the same in the petroleum industry because of the complex oil–gas reservoir. A limitation remains for dense shale exploration in that the shales with invisible bedding are difficult to characterize measurably because of the considerable complexity of the geological structures. The oblique-incidence reflectivity difference method (OIRD) is sensitive to the surface features and was used to obtain a layered distribution of dielectric properties in shales. In this paper, we report a combination of OIRD and deep learning method to identify the dielectric anisotropy of an invisible-bedding shale. The model performs well and clearly identifies the bedding of the shale based on the output values associated with the probability. Only a single direction was determined to have laminations with widths of 20–60μm. The anisotropy features detected by OIRD also existed in the invisible-bedding shale and were caused by the smaller cracks and denser particles’ orientation relative to general shales. As current dense reservoirs include rich invisible-bedding shales, we believe that the OIRD method combined with deep learning method can help improve the exploration efficiency of shale reservoirs.

An accurate, nondestructive, and economic prospecting technique is of utmost significance to explore petroleum resources in desert, however, the typically used technologies fail to provide direct and noninvasive detection. Here, we demonstrated a terahertz (THz) prospecting method for predicting the distribution of oil reservoir by extracting the sands from the surface areas in a desert oilfield. The accuracy of THz prospecting reached to more than 80%. The trace organic matters migrating from underground reservoir to surface sands can be detected by THz spectroscopy, which was the mechanism of THz spectroscopy for reservoir exploration. The long-chain alkanes, nitro organics, and aromatic compounds were also confirmed by thermogravimetric analysis system coupled with Fourier transform infrared and mass spectroscopy. When the trace organics were decomposed from sands, the THz response was equivalent to that of other sands. Consequently, the petroleum prospecting method on the basis of THz spectroscopy is useful for the improvement and optimization of geophysical exploration system in desert.

Intelligent actuating materials with vapor-stimulated mechanical response usually require complicated synthesizing processes or have a high cost. Here, we found that the UV/O3-modified poly(dimethylsiloxane) PDMS) film can show spontaneous curling deformation when it encounters small alcohol molecules such as ethanol vapor. Based on the coupling of the vapor-responsive PDMS film and triboelectric nanogenerator (TENG), a flexible actuator for object transport and a double-finger gripper for loading small objects are designed. The deformation and size change induced by vapor stimulation help these devices to adapt to the target objects of different sizes, while the electrostatic force provided by TENG can move or control the target object, for instance, the double-finger gripper can clamp an object of a weight of 6 g.

The computer mouse is one of the most common tools used for human-machine interfacing. The human behavior studying by click operation using an intelligent mouse and related security identification of computers remains a great challenge. Here, we develop an intelligent mouse embedded with a contact-separation adaptable triboelectric sensor based on the intrinsic mouse button click operation. With the unique characteristics of different individuals who use the intelligent mouse and machine learning algorithms, an identity recognition system was designed. Through processes such as signal processing, feature extraction, and model training, high-accuracy (98.4%) identification of different individuals based on the signals from the embedded triboelectric sensor in the mouse was achieved. In addition, we have developed a security alarm system for detecting unauthorized users operating the computer, and successfully validated the practicality of this system. A system for monitoring user behaviors while operating the computer has been designed to meet the monitoring needs of user computer usage states. This system can monitor users' gaming, working, or studying states, while effectively protecting users' privacy. In general, this work reveals a new strategy for security identification of computers which can be potentially applied in cyber and information security.

It is difficult for triboelectric nanogenerators (TENG) to harvest energy with high humidity environments, due to the screening effect of water. The resistance of TENG with atmosphere humidity has been studied by many previous works, while the energy generation of TENG on highly wetted or even water-bearing surface has not been thoroughly studied. Hence, we propose an octopus tentacle inspired micro patterns on the interface of TENG, which can provide two kinds of functions. The honeycomb-shaped micro patterns on tribo-electrification interface can maintain the energy generation on highly wetted condition and the similar patterns on the hydrogel surface can also achieve good adhesive capability on water-bearing substrates. The contact interface with honeycomb-shaped micro patterns can facilitate the water drainage during the pressing motion, which can increase the effective contact area for electrification. The open-circuit voltage (Voc) of the TENG with patterned tribo surface can reach 78 V on highly wetted surface, which is two times higher than that of a planar device. On the other hand, the similar honeycomb-shaped micro patterns have been applied on the surface of tough PA hydrogel. Accordingly, a hydrogel based TENG with repeatable adhesive capability is prepared, which allows TENG device to be adhered on the water-bearing substrate and harvest water wave energy. The demonstrated designed concept of this honeycomb-shaped micro patterns interface has excellent applicability in water-bearing environment and water wave energy harvesting process, enhancing device usability and promoting its practical applications.

Triboelectric nanogenerators (TENGs) have been widely applied for energy harvesting and self-powered sensing, whereas smart deformable materials can be combined with the TENG to acquire a more intelligent and self-adaptive system. Here, based on the vapor-driven actuation material of a perfluorosulfonic acid ionomer (PFSA), we propose a type of humidity-responsive TENG. The integrated TENG array can automatically bend to the desired angles in response to different humidity conditions, and thus, it can effectively collect energy from both wind and rain drops, where the power density can reach 1.6 W m–2at a wind speed of 25 m s–1and 230 mW m–2under rainy conditions. Meanwhile, this TENG array can fully lay down in dry weather, using the reflective surface to reflect sunlight and heat radiation. The vapor absorption process of the PSFA film can also result in the charge accumulation process. Accordingly, relying on the strong absorption capability of PFSA, a TENG-based vapor sensor with high sensitivity has been developed for monitoring chemical vapor leakage and humidity change. This work opens up a promising approach for the application of the humidity-responsive materials in the field of energy harvesting and self-powered sensors. It can also promote the development of TENG toward a more intelligent direction.

In recent years, wearable triboelectric nanogenerators (TENGs) and related on-skin nano-systems are drawing massive attentions due to their potential applications in sensory devices, electronics skins and portable energy packages. However, most of these TENG devices still employ adhesive tape to attach on human skin, which may cause many side effects, such as inflammation, allergy and discomfort symptoms in the long term. Therefore, it is quite necessary to find a simple and skin-friendly bonding method to directly stick TENG to human skin. Here, we fabricated a blended nanofiber membranes (NM) which is obtained by the mixed electro-spinning technique using polyvinyl alcohol and polyvinylidene fluoride nanofibers. This blended NM can directly attach on skin with the help of a tiny amount of water and no uncomfortable symptoms or allergy can be found during a long period of operation. The TENG device based on this NM can not only achieve good output performance, but also realize a wearable energy generator with inflammation-free and highly gas-permeable characteristics. The blended NM have excellent air permeability (Gurley value = 1.4 s/300 ml-3.3 s /300 ml). The demonstrated concept of this skin-friendly bonding method and NM-based TENG have promising applications in the field of wearable/potable sensory devices, electronics skins, artificial muscles, flexible robots and so on.

Piezoelectric organic–inorganic lead halide perovskites have recently attracted much attention in the field of optoelectronic devices. However, their piezoelectric properties as a possible way to modulate device performances have rarely been reported. Here, we study experimentally a photodetector based on CH3NH3PbI3(MAPbI3) single crystals, whose performance is effectively modulated viaan emerging effect—the piezo-phototronic effect, which is to use the piezoelectric polarization charges to tune the optoelectronic processes at the interface. A piezoelectric coefficient of 10.81 pm/V of the CH3NH3PbI3single crystal is obtained. Under 680 nm laser illumination with a power density of 3.641 mW/cm2and at an external bias of 2 V, compared to the case without straining, the light current of the photodetector is enhanced by ∼120% when a 43.48 kPa compressive pressure is applied. The response speed of the photocurrent is 3 and 2 times faster than the cases without applying pressure for the light-on and light-off states, respectively. This work proves that the performance of the photodetector based on MAPbI3single crystals can be effectively enhanced by the piezo-phototronic effect, providing a good method for optimizing the performance of future perovskite-based optoelectronic devices.

Electrowetting technique is an actuation method for manipulating position and velocity of fluids in the microchannels. By combining electrowetting technique and a freestanding mode triboelectric nanogenerator (TENG), we have designed a self-powered microfluidic transport system. In this system, a mini vehicle is fabricated by using four droplets to carry a pallet (6 mm × 8 mm), and it can transport some tiny object on the track electrodes under the drive of TENG. The motion of TENG can provide both driving power and control signal for the mini vehicle. The maximum load for this mini vehicle is 500 mg, and its highest controllable velocity can reach 1 m/s. Freestanding TENG has shown excellent capability to manipulate microfluid. Under the drive of TENG, the minimum volume of the droplet can reach 70–80 nL, while the tiny droplet can freely move on both horizontal and vertical planes. Finally, another strategy for delivering nanoparticles to the designated position has also been demonstrated. This proposed self-powered transport technique may have great applications in the field of microsolid/liquid manipulators, drug delivery systems, microrobotics, and human-machine interactions.

Biomolecule-based materials have attracted increasing attention for the fabrication of environmental-friendly triboelectric nanogenerators (TENGs) owing to the inductive effect with strong electron-donating ability from NH2groups. However, understanding the relationship between molecular packing and performance is extremely challenging due to the complex structures, thus limiting the designability of highly efficient triboelectric biomaterials at the molecular level. Here, we describe minimalistic yet mechanically robust ordered amino acid crystals formed by physical vapor deposition and utilized as positive triboelectric materials. The morphologies and electrostatic potential could be optimized by rationally tuning the chirality-dependent supramolecular spatial arrangement, which results in a 50% increase in the output voltage of the corresponding TENGs. Interestingly, the electric field-induced directional molecular packing results in a surface comprising charged amino groups that could easily lose electrons for charge separation, which more than doubled the output voltage of TENGs. The amino acid crystal-based TENG showing enhanced performance could serve as a micro-power source to drive light-emitting diodes and as a sensor to detect body movements. Our work provides insight into exploring the triboelectric effect of biomaterial crystals and paves an avenue to high-performance electric devices for bioengineering applications by designing biomolecule-based functional materials.

The push for green and eco-friendly materials has intensified, driven by the mounting environmental concerns associated with traditional petroleum-based products. As land resources shrink and space for development narrows, marine biomaterials have emerged as a promising alternative over the past decades. Well-known for their vast availability, outstanding biocompatibility, impressive biodegradability, and minimal toxicity, marine biomaterials present an ideal foundation for developing eco-friendly triboelectric nanogenerators (TENGs). In this review, we present the evolution of TENGs based on marine biomaterials, from their core working principles to their multifaceted applications. We begin by elucidating the operational modes and foundational principles of TENGs. Next, we highlight the intrinsic qualities and advantages of marine biomaterials commonly utilized in TENG designs. Additionally, we discuss approaches adopted to amplify the efficacy of TENGs derived from marine biomaterials. A synthesis of documented applications of these TENGs from existing literature is then presented. We finally discuss the existing challenges and future directions in marine biomaterial-inspired TENGs.

Wind energy has played a reasonable proportion in the current energy structure, extracting energy from wind sources attracts extensive attention in the era of global carbon neutrality. However, traditional wind turbine based on electromagnetic generator are not economic in some cases, the new technology demand for complementing conventional approaches is proposed. Recently, the emerging triboelectric nanogenerator (TENG) technology based on the coupling of contact electrification and electrostatic induction have been widely researched and utilized to scavenge wind energy, with the advantages of high efficiency, low cost and portability. Here, the recent advances of wind harvesters based on TENG are reviewed, where the material, structure design, power management and the developed strategies to optimize the performance of TENG-based wind harvesting system are summarized. Meanwhile, the hybridization of TENG with other types of energy harvesting techniques is discussed. Finally, the application, outlook and challenge in the growth of TENG-based wind harvester are outlined.

Wind is one of the cleanest energy sources, and various wind energy harvesters have been proposed. Here, we study the vibration behavior and excitation mechanism of an ultra-stretchable electrode film, using which the fabricated TENG device if for wind energy harvesting. The motion of the ultra-stretchable film in the flow is illustrated as a coupling of vortex-induced elastic torsional deformation and pressure-driven galloping. Aerodynamic models based on structural mechanics and computational fluid dynamics (CFD) are established to systematically elaborate the deformation characteristics. On the basis of aerodynamic characteristics, perforations are developed on the electrode film as geometric optimization to enhance performance of the TENG, in which the output power has been improved for 56.3% in comparison to the original device. This work firstly demonstrates the flow-induced vibration of the ultra-stretchable film in TENG, which may paves a way for improving the design of miniature wind energy harvesters.

Ionic polymer-metal composites (IPMCs), a kind of electroactive polymer, have been considered as artificial muscle due to their deformation in response to electrical stimulation. However, the needing of external power supply severely limits IPMC's wide applications. Herein, newly developed energy harvesting technique of triboelectric nanogenerator (TENG) is used to directly drive IPMC, in order to establish a self-powered actuation system. Even though IPMC cannot utilize the voltage signal from TENG, it is possible for IPMC to accumulate the transferred charge from several motion cycles of TENG. Hence, the combined TENG-IPMC system also develops a new approach for utilizing the current signal from TENG as the control signal. Comparing with IPMC under the drive of power source, TENG-IPMC system needs much lower (about 0.1%) transferred charges to achieve the same bending angle than that of DC power. The actuation of TENG-IPMC system can be controlled precisely through the design of TENG, which can be utilized for several intelligent electromechanical applications, including self-powered gripper, tunable laser projector, and soft robotic in liquid. The TENG-IPMC system has many advantages, such as high energy conversion rate, small size, and low cost, which will significantly improve the usability and portability of IPMC.