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Abstract Triboelectric nanogenerators (TENGs) are revolutionizing mechanical‐to‐electrical energy harvesting. TENGs harvest energy through the polymer–polymer contact electrification (PCE) mechanism, driven by nanoscale processes at the contact interface. Currently, when discussing PCE there are two distinct schools of thought on which nanoscale interactions drive charging at the contact interface; 1) electron transfer, where orbital overlap leads to charge tunneling between polymers; or 2) mass (material) transfer, where polymer chain entanglement and intermolecular bonding leads to heterolytic bond scission. Here, a combination of in silico and benchtop experiments is used to elucidate the relative role of electron and mass transfer in PCE. In silico experiments show that covalent bond scission in a polymethylmethacrylate/polytetrafluoroethylene system occurs at 348 kcal mol−1, prior to electron cloud overlap, where the highest occupied molecular orbital and lowest unoccupied molecular orbital of the system remain separated by 163 kcal mol−1. Benchtop experiments show PCE‐generated charges cannot be simply discharged via electrical grounding, indicating the formation of bound surface charge from mass transfer. The calculations and contact‐electrification tests provide strong evidence to support mass transfer being the leading mechanism driving PCE.

Spark discharge is essential for extracting energy from triboelectric nanogenerators (TENGs). However, the lack of universal technical standards for most discharge switches limits their widespread application. Herein, a buck circuit utilizing gas discharge tube (GDT) as discharge switches is presented. The GDT switch significantly enhances the instantaneous power to 30 mW, 15 times higher than the direct method. When VGDT (the breakdown voltage of GDT) ≤1000 V, it can be integrated with an LC converter, forming the GDTx‐Buck circuit with a maximum energy conversion efficiency of 92.2%. When VGDT >1000 V, GDT can combine with a transformer, forming the GDT‐nT circuit, which enables higher voltage power management. The results demonstrate GDT's universal applicability, reducing circuit complexity during design. In practical applications, the circuit can illuminate 1250 LEDs at an ultra‐low operating frequency of 0.6 Hz, generating electromagnetic waves during GDT breakover, which proves valuable for self‐powered wireless applications. Additionally, the circuit drives parallel calculators and thermometers at 2 Hz in micro‐nano energy applications and provides continuous power to high‐power fire sensors. Its high integration and simple design render it highly promising for large‐scale energy management applications based on TENGs. [ABSTRACT FROM AUTHOR]

The triboelectric nanogenerator (TENG) represents a burgeoning approach for harvesting ambient mechanical energy. However, practical applications suffer from the issues of insufficient charge density and material abrasion. Here, a rotational TENG that attains exceptional output performance and durability in mechanical energy harvesting and couples an ingenious coplanar charge pump by soft contact with a suspended electrostatic induction mode is presented. Thanks to the continuous and synchronous charge injection from the central charge pumping unit, the charge density can be up to 74.62 µC m−2, resulting in an outstanding peak power density of 20.72 W m−2. Moreover, the utilization of yielding polyester fur in the charge pumping unit as a tribo‐layer for soft contact decreases the material abrasion and then enhances durability and robustness. And the experimental results show that the TENG can maintain 99.2% electrical output after 100 000 operating cycles. With the optimized design, the prototype can continuously drive four commercial lamps rated 12 W in series. Furthermore, a wireless powering system is demonstrated to power the electronics, demonstrating an extensive application of the TENG. Given the compelling characteristics, this work is expected to provide a sound strategy for improving TENGs' output and durability in the field of self‐powered sensor systems. [ABSTRACT FROM AUTHOR]

The flexible polyvinylidene difluoride (PVDF)/6H–SiC composite films are fabricated to overcome the natural brittleness of hexagonal SiC. Yet the electrical output of the piezoelectric nanogenerator (PENG) based on the composite film needs to be further improved. Here, PENG and hybrid nanogenerator exploiting both triboelectric and piezoelectric effects (T-PENG) based on PVDF/6H–SiC composite films are assembled. The PENG based on the PVDF/15 wt% 6H–SiC composite film shows the open circuit voltage (V oc) of 16.81 V. The T-PENG achieves the bridge rectified voltage of 65.70 and 136.58 V when subjected to the external force of 1.1 and 4.9 N, indicating 3.91 and 7.39 times the output of the PENG under the same force, which is the highest value compared with the reported nanogenerators based on SiC and SiC composites. This work breaks through the limitation of low mechanical energy utilization efficiency of film-based PENG and provides a feasible way to enhance the electrical output of nano power sources. [ABSTRACT FROM AUTHOR]

Low‐cost and efficient large‐scale triboelectric nanogenerator (TENG) is considered as the new scheme for distributed mechanical conversion or renewable energy utilization. An extremely popular all‐inorganic lead‐free double perovskite Cs2AgBiBr6 (CABB) has emerged as extraordinary potential material in triboelectric semiconductors' substitution, overcoming high‐impedance limitations associated with organic‐polymer‐insulator based materials. In this study, assembled by the certified available positive frictional material CABB, TENG with sandwiched structure of ITO/compact‐TiO2/mesoporous‐TiO2/CABB – the poly‐tetra‐fluoroethylene/Al exhibits appropriate performance on environmental stability and output capacity for which structure can impede charges decay. Fabrication process comparison shows that as an inexpensive large‐scale functional films preparation method, sprayed CABB TENG with brilliant relative dielectric constant and work function difference possess more distinguished output characteristics. This is confirmed by higher open‐circuit voltage of 105 V, larger short‐current density of 2.45 mA m−2 at 0.25 Hz motion parameter, and more abundant output power density of 0.76 W m−2 under 10 Hz. Further study confirms that both higher frequency and larger contact‐area are conducive to total output power, while terminal charging speed is inversely or positively proportional with capacitance or mechanical frequency. Final physical display effect of sprayed CABB TENG lights up at least 53 commercial yellow‐LEDs, holding decent energy conversion ability. [ABSTRACT FROM AUTHOR]

Progress in advanced electronics has initiated the investigation of new ways to develop and apply self‐powered smart devices. The concern for meteoric exhausting non‐renewable energy sources has spurred such endeavors. Even so, using external power sources like batteries is problematic due to limited capacity, maintenance inconvenience, replacement, and environmental hazards. Triboelectric nanogenerators (TENGs) capable of converting various forms of mechanical energies into electrical output are gaining popularity. The marine and coastal areas are abundant sources of salvable mechanical energy. TENGs can convert lower‐frequency, ununiform, multidirectional energies into usable electricity. This can solve the device‐powering problem and can generate diverse signals to act as monitoring or sensing platforms themselves. In this review, three main TENG‐based/TENG‐driven application themes are addressed, i.e., energy harvesting, marine environment monitoring, and self‐powered equipment for marine‐related activities. It attempts to emphasize that various design features of TENGs can influence output performance; TENGs can power devices and monitor ocean parameters; TENGs‐integrated modern IoT networking systems can transmit real‐time data. Overall, this review encompasses the fundamental working mechanisms, structure designs, and practical implementation scenarios of recently developed devices in diverse marine applications. Finally, the existing challenges and potential future directions for TENG‐based marine self‐powered electronic systems are discussed. [ABSTRACT FROM AUTHOR]

Converting mechanical energy into photon emission provides a promising route for intelligent sensing, self‐powered lighting, and distributed energy harvesting, which is of great significance for finding a feasible solution to the current sensing technical bottleneck and energy crisis. As the basis for understanding the conversion mechanism and realizing high‐frequency mechanical energy utilization, elucidating the dynamic process of intensity variation in the mechano‐to‐photon conversion remains a great challenge. Herein, a time‐domain characterization scheme that enables to unravel the intrinsic decay of mechanoluminescence (ML) with lifetimes from milliseconds down to tens of microseconds is constructed. It is demonstrated that ML decay characterization is an important tool to reveal the dynamics of charge migration in ML materials. The ML decay in a typical self‐reproducible ML material ZnS:Mn2+ shows temperature dependence and stress fluctuation resistance, which opens up a new reliable approach for self‐powered and remote temperature sensing. Finally, benefiting from the shortest ML lifetime recorded to date, an ultrafast‐response stress sensor that enables to detect individual pulses of ultrasonic waves with ML sensing technology is developed. [ABSTRACT FROM AUTHOR]

This paper demonstrates that air‐stable radicals enhance the stability of triboelectric charge on surfaces. While charge on surfaces is often undesirable (e.g., static discharge), improved charge retention can benefit specific applications such as air filtration. Here, it is shown that self‐assembled monolayers (SAMs) containing air‐stable radicals, 2,2,6,6‐tetramethylpiperidin‐1‐yl)oxidanyl (TEMPO), hold the charge longer than those without TEMPO. Charging and retention are monitored by Kelvin Probe Force Microscopy (KPFM) as a function of time. Without the radicals on the surface, charge retention increases with the water contact angle (hydrophobicity), consistent with the understanding that surface water molecules can accelerate charge dissipation. Yet, the most prolonged charge retention is observed in surfaces treated with TEMPO, which are more hydrophilic than untreated control surfaces. The charge retention decreases with reducing radical density by etching the TEMPO‐silane with tetrabutylammonium fluoride (TBAF) or scavenging the radicals with ascorbic acid. These results suggest a pathway toward increasing the lifetime of triboelectric charges, which may enhance air filtration, improve tribocharging for patterning charges on surfaces, or boost triboelectric energy harvesting. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Harvesting vibration energy using a triboelectric nanogenerator (TENG) is a promising approach in solving the power supply restriction of the Internet of Things. Currently, the low durability due to friction surface wearing is the primary limitation of TENGs, which restricts their applicability and practicability. This study introduces a non-contact-type TENG aimed at significantly enhancing its durability by increasing its anti-wear capability. The configuration of the proposed TENG includes permanent magnets and rolling-balls. The reciprocating motion of functional friction surfaces, facilitated by the permanent magnets, enhances the efficiency of harvesting low-frequency vibration energy. The embedded rolling-balls are utilized to separate two functional friction surfaces, which minimizes the friction surface wearing between different dielectric materials. The electrical output characteristics of this non-contact TENG under variable load resistances are explored according to sinusoidal excitation based on either variable frequencies or accelerations. The results demonstrate that the proposed nanogenerator can generate a short-circuit current of 2118.2 nA and achieve a peak power density of 9.891 mW/m2. The electrical responses of this non-contact TENG remain stable over 120 000 continuous working cycles, lasting for more than 200 min. Furthermore, the nanogenerator can identify and harvest energy from running or jumping motions performed by individuals in different postures and at various speeds or heights. With its exceptional durability and stability, this non-contact nanogenerator offers a novel approach to low-frequency vibration energy harvesting, paving the way for practical applications in the field. [ABSTRACT FROM AUTHOR]

In recent years, self-power sensing systems based on triboelectric nanogenerators (TENGs) have been extensively studied. However, pure polymer friction materials are not satisfactory in terms of their triboelectric properties and cannot meet the needs of high-performance TENGs. We have improved the performance of a polymer electrode-based TENG by increasing the specific surface area of the material as well as the dielectric constant of the triboelectric layer. Benefitting from the enhanced dielectric constant engineering and high surface area engineering, the BaTiO3@CMC-based TENG exhibits excellent output performance which is 3 times higher than that of a pure CMC-based TENG. As expected, the obtained self-powered TENG can be used to monitor the wind speed with a high sensitivity of 1.97 V/(m s−1). In addition, the obtained sensor system can accurately map the contact position and touch trajectory of the object when assembling the TENG with a 4 × 4 array on an acrylic substrate. This work will provide basic insights into improving the performance of TENGs and widen their applications in the field of sensing. [ABSTRACT FROM AUTHOR]

The lack of theoretical understanding of triboelectrification has hindered the development of energy harvesting technologies like triboelectric nanogenerators. Focusing on polytetrafluoroethylene, a material with a strong triboelectric output, a model predictive of its triboelectric behavior, driving the development of improved nanogenerators are formulated. With a combined computational‐experimental approach it is shown that defluorination enhances polytetrafluoroethylene nanoscale triboelectric charging. Then a model, explaining the macroscale triboelectric output as determined by the competition of two mechanisms is developed. Defluorination enhances charging while also reducing the interface gap, favoring the backflow of electrons, and possibly reducing charging. However, numerical analysis shows that backflow is negligible, aligning with the prediction of increased triboelectric output. By building triboelectric nanogenerators with defluorinated polytetrafluoroethylene samples, achieved by X‐ray irradiation, a one‐order‐of‐magnitude output increase is demonstrated. The predictive models, supported by experiments, lead to an improved strategy for designing effective energy harvesting devices and new applicative breakthroughs. [ABSTRACT FROM AUTHOR]

Considering the ever-increasing human need for energy resources and on the other hand, the reduction of fossil fuel resources, the use of renewable energy has become one of the attractive topics of researchers. One of the available and ambient sources in nature is mechanical energy in nature, such as the energy of body movements, wind energy, energy in sea waves, etc. One of the methods of converting and extracting energy from the mentioned forms is the use of triboelectric nano generators. Triboelectric nanogenerators have various structures. In the current research, the contact mode and two electrodes of triboelectric nanogenerators have been discussed and also the relationships governing the nano generator have been calculated. By comparing the response of the nano generator in ideal and non-ideal state, it can be understood that considering the effects of edge capacitors will be effective on the final response of the nano generator. Finally, the effect of various parameters on the performance of the triboelectric nano generator has also been investigated. [ABSTRACT FROM AUTHOR]

Anti‐counterfeiting and visual optical information encryption/decryption technology have attracted widespread attention in the field of information security. Luminescent encryption technologies still face a huge challenge in external high voltage power supply, complex architecture, and expensive decryption equipment, which hinder their broad applications. Herein, a wearable integrated self‐powered electroluminescent (EL) display device (W‐ELD) that consists of MXene/Silicone‐based triboelectric nanogenerator (MS‐TENG) and EL device based on a shared MXene electrode is developed for patterned display and information encryption. The W‐ELD features an all‐in‐one MXene electrode with excellent flexibility and high conductivity of 0.6 kΩ sq−1, which is shared by both MS‐TENG and EL devices. The MS‐TENG demonstrates excellent output performances (output power of 0.9 Wm−2) and high stability and durability (104 cycles), which can directly light up the flexible patterned EL device. More importantly, when dripping conductive electrolyte solution, the W‐ELD based on "中國"‐patterned MXene electrode can precisely reveal the encryption information through self‐powered EL emission for real‐time visualized information interaction. Consequently, the all‐in‐one MXene electrode‐based W‐ELD that integrates both MS‐TENG and EL device demonstrates exceptional patterned EL‐based information encryption features, which offers a potential prospect in wearable self‐powered optoelectronic devices, flexible displays, and encryption technology. [ABSTRACT FROM AUTHOR]

The emergence of tribovoltaic nanogenerators (TVNGs) paves the way for developing a new kind of semiconductor‐based energy harvester that overcomes the restriction of low output current in a conventional approach. The traditional TVNG generally depends on the frictional pair between two rigid semiconductors (or metal‐semiconductor), limiting the practicability of flexible and portable electronics. Recent developments require the fundamental understanding of charge generation in diverse operating modes and structures. Here, a flexible TVNG based on the p‐Cu2O/n‐g‐C3N4 interface is presented. Operating in a freestanding mode, the proposed TVNG can generate a stable signal in any optical conditions including UV illumination, dark, and ambient. Under UV illumination, the electrical outputs of the TVNG reach 0.43 V and 2.1 µA cm−2, which are significantly larger than those obtained from dark and ambient conditions. The results demonstrate the coupling effect of three phenomena: tribovoltaic, photovoltaic, and triboelectric effects, and the unique mechanism to the observed signal is proposed. Additionally, the TVNG shows the practical feasibility of energy harvesting with capacitor charging and charge‐boosting circuits. This study showcases the unique concept with potential for developing a novel flexible nanogenerator in many aspects, including material, structure, and fundamental mechanism. [ABSTRACT FROM AUTHOR]

MXene materials emerge as promising candidates for energy harvesting and storage application. In this study, the effect of the surface chemistry on the work function of MXenes, which determines the performance of MXene‐based triboelectric nanogenerator (TENG), is elucidated. First‐principles calculations reveal that the surface functional group greatly influences MXene work function: OH termination reduces the work function with respect to that of bare surface, while F and Cl increase it. Then, work functions are experimentally determined by Kelvin probe force microscopy. The MXene prepared by gentle etching at 40 °C for 48 h (GE40/48) has the largest work function. Furthermore, an electron‐cloud potential‐well model is established to explain the mechanism of electron emission‐dominated charge transfer and assemble a triboelectric device to verify experimentally its conclusions. It is found that GE40/48 has the best performance with a 281 V open‐circuit voltage, 9.7 µA short‐current current, and storing 1.019 µC of charge, which is consistent with the model. Last, a patterned TENG is demonstrated for self‐powered human–machine interaction application. This finding enhances the understanding of the inherent mechanism between the surface structure and the output performance of MXene‐based TENG, which can be applied to other TENG based on 2D materials. [ABSTRACT FROM AUTHOR]

Currently, the research on improving charge density of charge‐excitation triboelectric nanogenerators (CE‐TENG) mainly focuses on surface modification and thinning of organic polymer materials. However, to increase durability and output, the exploration of high permittivity and high‐thickness inorganic materials is important for extensive applications. Meanwhile, the physical mechanism of air ionization caused by air breakdown during secondary self‐charge excitation (SSCE) needs to be explored. Herein, this study proposes a new strategy for CE‐TENG based on inorganic materials by de‐trapping reverse charge and increasing the contact barrier difference to obtain high charge density and achieve secondary self‐charge excitation. SSCE of three types of films with different leakage currents are evaluated according to their trapping and de‐trapping reverse charges. It is found that the trap distribution of dielectric films with larger leakage currents are mostly shallow‐level traps, whose de‐trapping ability becomes stronger after reverse charge injection. By regulating the contact barrier difference with thin organic polymer on thick inorganic high permittivity material, this study has achieved a high charge density of 1310 µC m−2 with a fast start‐up time of SSCE, which is a new record for the charge density of inorganic materials. This study promotes TENG of inorganic materials toward high‐energy output applications. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator is becoming one of the most efficient energy harvesting device among all mechanical energy harvesters. This device consists of dielectric friction layers and metal electrode which generates electrical charges using electrostatic induction effect. There are several factors influencing the performance of this generator which needs to be evaluated prior to experiment. The absence of a universal technique for TENG simulation makes the device design and optimization hard before practical fabrication, which also lengthens the exploration and advancement cycle and hinders the arrival of practical applications. In order to deepen the understanding the core physic behind the working process of this device, this work will provide comparative analysis on different modes of TENG. Systematic investigation on different material combination, effect of material thickness, dielectric constant and impact of surface patterning is evaluated to shortlist the best material combination. COMSOL Multiphysics simulating environment is used to design, model and analyze factor affecting the overall output performance of TENG. The stationary study in this simulator is performed using 2D geometry structure with higher mesh density. During this study short circuit and open circuit condition were applied to observe the behavior of charge and electric potential produced. This observation is analyzed by plotting charge transfer/electric potential against various displacement distances of dielectric friction layers. The ouput is then provided to load ciruitary to measure the maximum output power of the models. Overall, this study provides an excellent understanding and multi-parameter analysis on basic theoretical and simulation modeling of TENG device. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) are a kind of mechanical energy harvester with a larger force sensing range and good energy conversion, which is often applied to human kinetic energy collection and motion sensing devices. Polymer materials are the most commonly used materials in TENGs' triboelectric layers due to their high plasticity and good performance. Regarding the application of TENGs in insoles, research has often used brittle Teflon for high output performance together with hard materials, such as springs, for the mechanism to maintain its stability. However, these combined materials increase the weight and hardness of the insoles. Here, we propose a polyethylene terephthalate (PET)-based TENG with a micro-needle polydimethylsiloxane (PDMS) elastomer, referred to as MN-PDMS-TENG, to enhance performance and maintain comfort flexibility, and structural stability. Compared with a flat PDMS, the TENG with a microstructure enhances the output open-circuit voltage (Voc) from 54.6 V to 129.2 V, short-circuit current (Isc) from 26.16 μA to 64.00 μA, power from 684 µW to 4.1 mW, and ability to light up from 70 to 120 LEDs. A special three-layer TENG insole mechanism fabricated with the MN-PDMS-TENG and elastic materials gives the TENG insole high stability and the ability to maintain sufficient flexibility to fit in a shoe. The three-layer TENG insole transforms human stepping force into electric energy of 87.2 V, which is used as a self-powered force sensor. Moreover, with the calibration curve between voltage and force, it has a sensitivity of 0.07734 V/N with a coefficient of determination of R2 = 0.91 and the function between force and output voltage is derived as F = 12.93 V − 92.10 under human stepping force (300~550 N). Combined with a micro-control unit (MCU), the three-layer TENG insole distinguishes the user's motion force at different parts of the foot and triggers a corresponding device, which can potentially be applied in sports and on rehabilitation fields to record information or prevent injury. [ABSTRACT FROM AUTHOR]

Flip-flop (FF) serves as a fundamental unit in various sequential logic circuits and complex digital electronic systems for generating, transforming, and temporarily storing digital signals. Nonvolatility plays a crucial role in FFs by ensuring instant data recovery after unexpected data loss. Nonvolatile flip-flop can quickly recover in a self-powered environment, making it suitable for application environments such as the Internet of Things (IOT). Unfortunately, most existing nonvolatile FFs (NVFFs) suffer from extended delays and high energy consumption during data backup and restore operations. In this paper, we propose two innovative voltage-controlled nonvolatile FFs (VC-FFs), namely VC-DFF (voltage-controlled D-FF) and VC-SRFF (voltage-controlled SR-FF), which address these challenges using voltage-controlled spin-orbit torque (VC-SOT) devices. The proposed designs are evaluated using a 40 nm CMOS process. Simulation results demonstrate that the proposed designs achieve significant improvements in write (recovery) energy consumption, with over 7.2× (1.54×) and 18.7× (2×) enhancements compared to their STT- and SOT-based counterparts, respectively. [ABSTRACT FROM AUTHOR]

The high surface charge density of triboelectric dielectric materials is the core of high output performance triboelectric nanogenerators (TENGs). However, the increase in surface charge density enabled by the existing triboelectric material modification is still far from the saturation value (σBS) limited by air breakdown. Here, utilizing the directional high electric field generated by the charge excitation technology of the voltage‐multiplying circuit, an ultrafast charge self‐injection strategy is proposed. An ordinary contact‐separation TENG with a working frequency of 1.5 Hz can realize charge self‐injection on the surface of its dielectric layer to a saturation value within 22 s. Furthermore, the surface charge on the dielectric layer after excessive charge self‐injection can be retained to the maximum value by the step‐by‐step discharge mitigation strategy. Finally, by using a 7 µm thick polyimide film, a super‐high charge density of 1480 µC m−2 is achieved after charge injection, which is the historical high by modification of single layer material series currently. The charge self‐injection technology combined with discharge mitigation strategy proposed in this work is an important breakthrough in the field of triboelectric layer modification. In addition, this work also provides a systematic discussion on the σBS of dielectric layer related physical mechanism. [ABSTRACT FROM AUTHOR]

The µW‐level power density of flexible piezoelectric energy harvesters (FPEHs) restricts their potential in applications related to high‐power multifunctional wearable devices. To overcome this challenge, a hierarchical design strategy is proposed by forming porous piezoceramics with an optimum microstructure into an ordered macroscopic array structure to enable the construction of high performance FPEHs. The porous piezoceramic elements allows optimization of the sensing and harvesting Figure of merit, and the array structure causes a high level of effective strain under a mechanical load. The introduction of a network of polymer channels between the piezoceramic array also provides increased device flexibility, thereby allowing the device to attach and conform to the curved contours of the human body. The unique hierarchical piezoceramic array architecture exhibits superior flexibility, a high open circuit voltage (618 V), high short circuit current (188 µA), and ultrahigh power density (19.1 mW cm−2). This energy density value surpasses previously reported high‐performance FPEHs. The ultrahigh power flexible harvesting can charge a 0.1 F supercapacitor at 2.5 Hz to power high‐power electronic devices. Finally, the FPEH is employed in two novel applications related to fracture healing monitoring and self‐powered wireless position tracking in extreme environments. [ABSTRACT FROM AUTHOR]

Due to their intrinsic flexibility, tunable conductivity, multiple stimulus‐response, and self‐healing ability, ionic conductive hydrogels have drawn significant attention in flexible/wearable electronics. However, challenges remain because traditional hydrogels inevitably faced the problems of losing flexibility and conductivity because of the inner water loss when exposed to the ambient environment. Besides, the water inside the hydrogel will freeze at the water icing temperatures, making the device hard and fragile. As a promising alternative, organogels have attracted wide attention because they can, to some extent, overcome the above drawbacks. Herein, a kind of organogel ionic conductor (MOIC) by a self‐polymerization reaction is involved, which is super stretchable, anti‐drying, and anti‐freezing. Meanwhile, it can still maintain high mechanical stability after alternately loading/unloading at the strain of 600% for 600 s (1800 cycles). Using this MOIC, high‐performance triboelectric nanogenerator (TENG) is constructed (MOIC‐TENG) to harvest small mechanical energy even the MOIC electrode underwent an extremely low temperature. In addition, multifunctional flexible/wearable sensors (strain sensor, piezoresistive sensor, and tactile sensor) are realized to monitor human motions in real time, and recognize different materials by triboelectric effect. This study demonstrates a promising candidate material for flexible/wearable electronics such as electronic skin, flexible sensors, and human‐machine interfaces. [ABSTRACT FROM AUTHOR]

Fibrous supercapacitor (FSC) is of great attention in wearable electronics, but is challenged by low energy density, owing to disordered diffusion pathway and sluggish redox kinetics. Herein, using micro‐reaction strategy, an anisotropic superstructure is developed by in situ anchoring ultrafine zinc sulfine (ZnS) nanoclusters on conductively ordered macro‐microporous carbon skeleton via interfacial CSZn bonds (ZnS/SOM‐C). The anisotropic superstructure affords 3D ordered macro‐microporous pathways, large accessible surfaces, and highly dispersed active sites, which exhibit enhanced electrolyte mass diffusion, rapid interfacial charge transfer, and large faradaic ions storage (capacitance of 1158 F g−1 in KOH aqueous solution). By microfluidic spinning, the ZnS/SOM‐C is further assembled into fibrous electrode of FSC that delivers high capacitance (791 F g−1), commercial‐level energy density (172 mWh g−1), and durable stability. As a result, the FSC can realize wearable self‐powered applications (e.g., self‐cleaning ventilatory mask, smartwatch, and display), exhibiting the superiority in new energy and wearable industry. [ABSTRACT FROM AUTHOR]

Self‐powered pressure sensors are gaining popularity in human–machine interaction and mobile systems for their energy efficiency. Among the many types of self‐powered sensors, triboelectric sensors have numerous advantages, including diversity of materials, ease of fabrication, and high voltage output. However, their signal is prone to be affected by both intrinsic and extrinsic factors including environmental change and discharging, which can significantly deteriorate the accuracy of measurement. To address this, a simple yet effective solution is proposed: a mechanically induced spike‐based self‐calibration method for a triboelectric pressure sensor. The sensor generates two signals: an open‐circuit voltage and a spiking calibration voltage, enabling real‐time calculation of current surface charge density. The calibration signal generates a spike at each predetermined discrete pressure change, whether positive or negative direction, denoting the corresponding direction of the pressure variation. This system successfully calibrates signals from various effects, including humidity change (20%–80%), discharging (over 10 days), and charge accumulation. This sensor has potential applications in precision agriculture for efficient crop harvesting and packaging in diverse environmental conditions. [ABSTRACT FROM AUTHOR]

This paper proposes a highly integrated triboelectric‐electromagnetic wave energy harvester (TEWEH) that can efficiently collect wide‐frequency wave energy and realize a self‐powered marine buoy. The innovative design of a permanent magnet‐polytetrafluoroethylene (PM‐PTFE) ball ensures high integration between the magnetic material forming the electromagnetic generator (EMG) and the dielectric material forming the triboelectric nanogenerator (TENG). In the condition of swinging (1 Hz and ±30°), the output of the TENG component can reach 230.25 V, 1.34 µA, and the average output of the EMG is 2.30 V, 10.43 mA. Remarkably, even at an extremely low frequency (0.2 Hz), the TEWEH maintains exceptional output. The output power density of the TENG component and EMG component reach 13.77 W m−3 and 148.24 W m−3, respectively, which are much higher than in previous work. The TEWEH can quickly charge the 330 µF capacitor to a certain voltage, and then light up navigation mark lights and power thermometers. A sealed TEWEH with circuits works as a self‐powered marine buoy that can transmit actual marine ambient temperatures to land. In conclusion, the TEWEH has broad application prospects in the field of wave energy harvesting and the self‐powered marine Internet of Things. [ABSTRACT FROM AUTHOR]

New stable frictional materials based on metal–organic frameworks (MOFs) are greatly desired for applications in self-powered systems. This work reports an ionic MOF material with efficient charge separation mediated by charge induction. ZUT-iMOF-1(Cu) is chemically stable and its triboelectric output performance surpasses those of traditional MOF materials. The short-circuit current of the iMOF triboelectric nanogenerator is 73.79 μA at 5 Hz. The output performance remains stable over 50 000 cycles of continuous operation. The charge and power densities peak at 123.20 μC m−2 and 3133.23 mW m−2. Owing to its high output performance, ZUT-iMOF-1(Cu) effectively prevents metal corrosion in cathodic-protection systems. Theoretical calculations show that increasing the charge-separation effect promotes the frictional electricity generation behaviour. This study provides research suggestions for ionic MOF frictional materials and will promote their application in self-powered electrochemical cathodic-protection systems. [ABSTRACT FROM AUTHOR]

To further improve the output performance of triboelectric devices, reducing charge attenuation and loss has become a hot research topic. Particularly, textiles have emerged as one of the promising research directions for triboelectric devices owing to their special internal structure and large specific surface area. In the present work, polyacrylonitrile fibers are fabricated with two distinct structures to provide a higher dielectric constant due to the strong polar properties brought about by higher dipole moment of the CN group. In addition, the complex and closely connected structure of the textile increases specific internal surface area. As a friction layer, the output voltage is shown to increase to 625% of the initial value (from 8 to 60 V) after the application of friction for a short time due to accumulation property. When acting as a trapping layer, the charge loss after injection is effectively prevented due to excellent charge trapping effect. After 24 h, the triboelectric output performance remains at ≈70% of the initial value (decreasing from 320 to 220 V), which is more than 20 times that of the polytetrafluoroethylene film, which decreases from 125 to 19 V. The device is realized for the advanced application of multi‐modal sensors. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) based on conjunctive effects of contact electrification (CE) and electrostatic induction are emerging as a new mechanical energy harvesting and sensing technique for promising applications in smart wearables, Internet of Things (IoTs), etc. The surface microstructure of a flexible triboelectric material for the increase of surface area is a common strategy for performance enhancement of TENGs, but the real roles of surface microstructures on their output performance are still not explicit due to the lack of suitable analysis tool and rational experimental design. Taking advantages of the surface-sensitive characteristic of CE effect, this work exploited and developed the electric signal patterns generated by single impact of TENGs as a kind of CE spectrum to analyze and speculate the real roles of surface microstructures of flexible triboelectric materials on the output performance of TENGs. Firstly, four different kinds of surface microstructures, namely planar surface (PS) and three combinations of two basic surface microstructures, i.e., micro lens arrays (MLAs), fabric textures (FTs), and hierarchical structures of MLAs on FTs (MLA/FTs), were elaborately designed and introduced for an identical triboelectric material (i.e., silicone elastomer) by a (micro)molding synthesis route. Then they were used for assembly of TENGs based on vertical contact mode to conduct performance evaluation under the same triggering conditions. Through systematic analysis and comparison of their highly repeatable CE spectra by programmed machine, it was found that the surface microstructure for a flexible triboelectric material to maximally enhance the output performance of a TENG shall achieve a positive synergistic effect of increasing triboelectric charge density, effective contact area and contacting/separating velocity, rather than simple increase of its surface area. [ABSTRACT FROM AUTHOR]

Since the Viking Labeled Release experiments were carried out on Mars in the 1970s, it has been evident that the martian surface regolith has a strong oxidizing capacity that can convert organic compounds into CO2 and probably water. While H2O2 was suggested originally for being the oxidizing agent responsible for the outcome of the Viking experiments, recent analyses of the martian regolith by the Phoenix lander and by consecutive missions point toward radiation-mediated decomposition products of perchlorate salts as the primary oxidant. In a series of experiments, we have shown that abrasion and triboelectric charging of basalt by simulated saltation could be an additional way of activating regolith. We have also shown that abraded basalt with a chemical composition close to that of martian regolith is toxic to several bacterial species and thus may affect the habitability of the martian surface. In the present study, we investigated the effect of the quantitatively most important minerals (olivine, augite, and plagioclase) and iron oxides (hematite, magnetite, and maghemite) on the survival of bacterial cells to elucidate whether a specific mineral that constitutes basalt is responsible for our observations. We observed that suspensions of iron-containing minerals olivine and augite in phosphate-buffered saline (1 × PBS) significantly reduce the number of surviving cells of our model organism Pseudomonas putida after 24 h of incubation. In contrast, the iron-free mineral plagioclase showed no effect. We also observed that suspending abraded olivine and augite in 1 × PBS led to a dramatic increase in pH compared to the pH of 1 × PBS alone. The sudden increase in pH caused by the presence of these minerals may partly explain the observed cytotoxicity. The cytotoxic effect of augite could be relieved when a strong buffer (20 × PBS) was used. In contrast, olivine, despite the stronger buffer, maintained its cytotoxicity. Iron oxides per se have no negative effect on the survival of our test organism. Overall, our experiments confirm the cytotoxicity of basalt and show that no single constituent mineral of the basalt can account for its toxicity. We could show that abraded iron-containing minerals (olivine and augite) change the pH of water when brought into suspension and thereby could affect the habitability of martian regolith. [ABSTRACT FROM AUTHOR]

This research aims to develop flexible semiconductors for triboelectric nanogenerator (TENG) applications. The sample powders of graphitic carbon nitride (g-C3N4) and copper (I) oxide (Cu2O) as N-type and P-type semiconductors, respectively, were synthesized. The semiconductors were prepared to be a composite film with alginate. The structure, morphology, and purity of the N- and P-type semiconductors were characterized using X-Ray diffraction and scanning electron microscopy techniques. Through the optical characterization, the N-type semiconductor showed the calculated energy band gap of 2.80 eV, while the P-type semiconductor was 1.90 eV. The P–N junction property of prepared samples was confirmed using a nonlinear current–voltage characteristic. After that, two flexible semiconductors were frictional paired for TENG. Through a vertical contact-separation mode, the P–N junction-based TENG produced a maximum output voltage and current of 3.90 V and 0.44 µA, respectively, with a maximum output power of 0.35 µW at 10 MΩ. In summary, the present work achieved the preparation of flexible P- and N-type semiconductors. The feasibility to harvest the mechanical energy was demonstrated in the TENG configuration. This idea is crucial for the future development of flexible harvesting/sensing devices using a novel concept. [ABSTRACT FROM AUTHOR]

Nanotechnologies are being increasingly widely used in advanced energy fields. Triboelectric nanogenerators (TENGs) represent a class of new-type flexible energy-harvesting devices with promising application prospects in future human societies. As one of the most important parts of TENG devices, triboelectric materials play key roles in the achievement of high-efficiency power generation. Conventional polymer tribo-negative materials, such as polytetrafluoroethylene (PTFE), polyvinylidene difluoride (PVDF), and the standard polyimide (PI) film with the Kapton® trademark based on pyromellitic anhydride (PMDA) and 4,4′-oxydianiline (ODA), usually suffer from low output performance. In addition, the relationship between molecular structure and triboelectric properties remains a challenge in the search for novel triboelectric materials. In the current work, by incorporating functional groups of trifluoromethyl (–CF3) with strong electron withdrawal into the backbone, a series of fluorine-containing polyimide (FPI) negative friction layers have been designed and prepared. The derived FPI-1 (6FDA-6FODA), FPI-2 (6FDA-TFMB), and FPI-3 (6FDA-TFMDA) resins possessed good solubility in polar aprotic solvents, such as the N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP). The PI films obtained via the solution-casting procedure showed glass transition temperatures (Tg) higher than 280 °C with differential scanning calorimetry (DSC) analyses. The TENG prototypes were successfully fabricated using the developed PI films as the tribo-negative layers. The electron-withdrawing trifluoromethyl (–CF3) units in the molecular backbones of the PI layers provided the devices with an apparently enhanced output performance. The FPI-3 (6FDA-TFMDA) layer-based TENG devices showcased an especially impressive open-circuit voltage and short-circuit current, measuring 277.8 V and 9.54 μA, respectively. These values were 4~5 times greater when compared to the TENGs manufactured using the readily accessible Kapton® film. [ABSTRACT FROM AUTHOR]

This study presents the numerical simulation, optimization, preparation, and characterization of Cu(In, Ga)Se2 (CIGS) thin-film solar cells (TFSCs). Different cell parameters were investigated, including Ga/(Ga+In) (GGI) ratios, the thicknesses of CIGS absorption layers, the fill factor (FF), the open-circuit voltage (Voc), and the short-circuit current (Isc). The effects of the simulated parameters on the power conversion efficiency (η) of each prototype CIGS cells were investigated. The optimal GGI ratio was approximately 0.6. Using COMSOL Multiphysics software, a CIGS layer thickness of 2 μm and an η of 17% was calculated, assuming constant operating temperatures. Moreover, prototype CIGS solar cells with various compositions were prepared via a simple and cost-effective method based on sol–gel, sonication, and spin-coating techniques. The microstructures and electrical and optical properties of the CIGS-based solar cells were evaluated using current–voltage (I-V) characteristics, scanning electron microscopy (SEM), X-ray diffraction, atomic force microscopy (AFM), and UV-vis spectroscopy. The elemental compositions of the solar cell layers were evaluated via energy-dispersive X-ray fluorescence (EDXRF). The obtained results were compared with the experimental results. For example, in a prototype cell with a CIGS absorption layer thickness of 2 μm and a GGI ratio of 0.6, the experimental value of η was about 15%. Our results revealed that the agreement between the simulation results and the experimental findings for most of the simulated parameters is quite good. These findings indicate that a non-destructive analysis based on EDXRF is a versatile tool for evaluating CIGS solar cells in a very short time with excellent repeatability for both layer composition and thickness. [ABSTRACT FROM AUTHOR]

The process of the aqueous synthesis of nanomaterials has gained considerable interest due to its ability to eliminate the need for complex organic solvents, which aligns with the principles of green chemistry. Fabricating nanostructures in aqueous solutions has gained recognition for its potential to develop ultrasensitive, low-energy, and ultrafast optoelectronic devices. This study focuses on synthesizing lead iodide (PbI2) nanoplates (NPs) using a water-based solution technique and fabricating a planar photodetector. The planar photodetectors (ITO/PbI2 NPs/Au) demonstrated a remarkable photosensitivity of 3.9 × 103 and photoresponsivity of 0.51 mA/W at a wavelength of 405 nm. Further, we have carried-out analytical calculations for key performance parameters including open-circuit voltage (Voc), short-circuit current (Isc), on-off ratio, responsivity (R), and specific detectivity (D*) at zero applied bias, while photodetector operating in self-powered mode. These values are as follows: Voc = 0.103 V, Isc = 1.93 × 10−8, on-off ratio = 103, R = 4.0 mA/W, and D* = 3.3 × 1011 Jones. Particularly, the asymmetrical output properties of ITO/PbI2 NPs/Au detector provided additional evidence of the effective creation of a Schottky contact. Therefore, the photodetector exhibited a photo-response even at 0 V bias (rise/decay time ~1 s), leading to the realization of self-powered photodetectors. Additionally, the device exhibited a rapid photo-response of 0.23/0.38 s (−5 V) in the visible range. This study expands the scope of aqueous-phase synthesis of PbI2 nanostructures, enabling the large-area fabrication of high-performance photodetectors. [ABSTRACT FROM AUTHOR]

With the advantages of superior wear resistance, mechanical durability, and stability, the liquid–solid triboelectric nanogenerator (LS-TENG) has been attracting much attention in the field of energy harvesting and self-powered sensors. However, most of the studies on LS-TENG focused on device innovations, changes in solid materials, and the effect of solid properties on output performance, and there is a lack of studies on liquids, especially at the molecular level. A U-tube LS-TENG was assembled to conduct experiments, whereby the effects of molecular structures, including molecular composition, carbon chain length, functional groups and material properties on the output performance were investigated. The deuterium replacing hydrogen and the atomic compositions could not achieve the enhancement of the output performance. Whether the chemical functional groups improve the output performance of LS-TENG depends on the mating solid material. Hydroxyl and cyanogenic groups can improve the output performance for the FEP case, while amide and cyanogenic groups can improve the output performance for the PTFE case. The order of output performances for functional groups of four groups of liquids with both FEP and PTFE materials is also obtained. It was also found that the dielectric constant is not positively correlated with the output performance. The results of this study might provide a reference for the deeper study and application of LS-TENG. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) have shown immense potential as self‐powering devices for energy harvesting, electronics, and self‐powered sensing devices. However, the performance of TENGs largely depends on the materials used, therefore, it is crucial to select appropriate materials. While dielectric polymers, metals, and inorganic materials have been commonly employed as active materials for TENGs, there is a need to explore new materials that offer improved performance. One promising material is two‐dimensional MXenes, which have shown exciting potential in various applications, including wearable sensors and electrochemical energy storage. For this reason, further research is needed to fully evaluate the performance of MXenes‐based TENGs and to determine their suitability for practical applications. This review emphasizes the significance of material selection in order to optimize the performance of triboelectric nanogenerators (TENGs). Here, the mechanism of TENGs is clearly explained for devices that convert mechanical energy into electric energy. The concept of the triboelectric effect is also described, which generates charge density on material surfaces, along with various types of TENG working modes. The selection of materials is thoroughly discussed, highlighting the growing interest in polymeric and biopolymeric materials, as well as functionalized and inorganic triboelectric materials. Also, exploration of materials that can enhance the output of TENGs, such as chemical modification techniques and the utilization of 2D materials like graphene and MXenes to improve triboelectricity is also included. The synthesis methods and techniques for MXenes are explored in detail. Furthermore, the performance of MXenes‐based TENGs for energy harvesting and self‐powered sensing is evaluated, and their potential applications in wearable devices are assessed. The study concludes by providing recommendations for future research on MXenes‐based TENGs and their applications in wearable devices. [ABSTRACT FROM AUTHOR]

Ensuring the reliability and stability of long‐distance power transmission requires monitoring the transmission lines' and grid environment's health. For this purpose, this study proposes a triboelectric nanogenerator (TENG) with anti‐self‐excited vibration. In case of aeolian vibration in the transmission line, the anti‐self‐excited oscillation triboelectric nanogenerator (AO‐TENG) generates electricity via cohesive work between the spring and the additional weight block that drives the TENG. As a result, this prevents excessive surge voltage from damaging the back‐end circuit, and the capacitor contributes significantly to voltage drop. This solution solves the issue that arises due to the TENG's high output voltage, making it difficult to power commercial sensors. This study presents a new design solution to facilitate smart grids that guarantee stable operation of distributed sensor nodes in the grids. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG)'s use is constrained by their surface charge density and alternating current output. This study therefore proposes a coupling output method combining charge excitation and phase shift to realize an almost constant high‐performance direct‐current (DC) and DC‐TENG is designed to harvest the energy of flowing water. The output characteristic of the DC‐TENG with or without charge excitation is thoroughly investigated in the experiment. The impact on the effectiveness of phases (P) and groups (G) is further proven by comparing and quantifying the current wave. The operation capability in a water environment is further demonstrated by the transmitted charge's attenuation of roughly 10.84% after the environment's humidity is increased to 90% RH. According to the findings of the investigation, DC‐TENG with 3P4G can reach almost constant DC with the root mean square value of 29.1 μA and the crest factor of 1.23. And the 220 μF capacitor can be charged to 5 V within 63 s and the peak output power of 9.18 mW is obtained. Finally, an experimental platform is established to simulate the water environment and the thermography is steadily powered. This scheme has reference significance to realize high‐performance DC output in the water environment. [ABSTRACT FROM AUTHOR]

Recently water droplet-based electricity generators (DEGs), which utilize triboelectricity between a droplet and a dielectric material, has a great attention. DEG generates an instantaneous high-power density despite its simple metal/dielectric/metal stack structure. In the DEG, the contact area between a droplet and a dielectric surface affects the output characteristics. We fabricated a DEG using a PTFE film as a dielectric material, measured the output voltage and evaluated the contact area in various dropping heights and positions. We demonstrated that the output peak voltage increased as the contact area increased related to spreading and rebounding of a droplet. [ABSTRACT FROM AUTHOR]

The development of renewable energy sources has grown increasingly as the world shifts toward lowering carbon emissions and supporting sustainability. Solar energy is one of the most promising renewable energy sources, and its harvesting potential has gone beyond typical solar panels to small, portable devices. Also, the trend toward smart buildings is becoming more prevalent at the same time as sensors and small devices are becoming more integrated, and the demand for dependable, sustainable energy sources will increase. Our work aims to tackle the issue of identifying the most suitable protective layer for small optical devices that can efficiently utilize indoor light sources. To conduct our research, we designed and tested a model that allowed us to compare the performance of many small panels made of monocrystalline cells laminated with three different materials: epoxy resin, an ethylene–tetrafluoroethylene copolymer (ETFE), and polyethylene terephthalate (PET), under varying light intensities from LED and CFL sources. The methods employed encompass contact angle measurements of the protective layers, providing insights into their wettability and hydrophobicity, which indicates protective layer performance against humidity. Reflection spectroscopy was used to evaluate the panels' reflectance properties across different wavelengths, which affect the light amount arrived at the solar cell. Furthermore, we characterized the PV panels' electrical behavior by measuring short-circuit current (ISC), open-circuit voltage (VOC), maximum power output (Pmax), fill factor (FF), and load resistance (R). Our findings offer valuable insights into each PV panel's performance and the protective layer material's effect. Panels with ETFE layers exhibited remarkable hydrophobicity with a mean contact angle of 77.7°, indicating resistance against humidity-related effects. Also, panels with ETFE layers consistently outperformed others as they had the highest open circuit voltage (VOC) ranging between 1.63–4.08 V, fill factor (FF) between 35.9–67.3%, and lowest load resistance (R) ranging between 11,268–772 KΩ.cm−2 under diverse light intensities from various light sources, as determined by our results. This makes ETFE panels a promising option for indoor energy harvesting, especially for powering sensors with low power requirements. This information could influence future research in developing energy harvesting solutions, thereby making a valuable contribution to the progress of sustainable energy technology. [ABSTRACT FROM AUTHOR]

This study investigates the piezoelectric and piezotronic properties of a novel composite material comprising polyvinylidene fluoride (PVDF) and antimony sulphoiodide (SbSI) nanowires. The material preparation method is detailed, showcasing its simplicity and reproducibility. The material's electrical resistivity, piezoelectric response, and energy-harvesting capabilities are systematically analyzed under various deflection conditions and excitation frequencies. The piezoelectric response is characterized by the generation of charge carriers in the material due to mechanical strain, resulting in voltage output. The fundamental phenomena of charge generation, along with their influence on the material's resistivity, are proposed. Dynamic strain testing reveals the composite's potential as a piezoelectric nanogenerator (PENG), converting mechanical energy into electrical energy. Comparative analyses highlight the composite's power density advantages, thereby demonstrating its potential for energy-harvesting applications. This research provides insights into the interplay between piezoelectric and piezotronic phenomena in nanocomposites and their applicability in energy-harvesting devices. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) technology is one of the new, low‐cost, and simple methods used to convert mechanical energy into electrical energy. Despite having so many advantages, the energy efficiency of this technology is extremely low. Therefore, their current performance needs to be improved so that they can be used more in daily life. Nanofibers (NFs) are one of the most important material groups that can be used for this technology due to their large surface area–volume ratio, easy production, low cost, and simplicity. Herein, Nylon 6.6 and polyacrylonitrile are used as tribopositive and tribonegative dielectric layers, respectively. To increase the output performances of the TENG system, different weight ratios (1, 2, 3 wt%) of phthalocyanine containing zinc‐based carborane units (ZnPc) are added into the Nylon 6.6 NFs. In accordance with the obtained results, the maximum open circuit voltage and power are measured as 228 V and 7.76 mW, respectively. These results correspond for the TENG system with 1% by weight ZnPc doped into the NFs. These results show that high‐efficiency TENG systems can be obtained with nanofiber‐based dielectric layers and can be used effectively in self‐powered systems. [ABSTRACT FROM AUTHOR]

Triboelectric charge transfer is complex and depends on contact properties such as material composition and contact area, as well as environmental factors including humidity, temperature, and air pressure. Saturation surface charge density on particles is inversely dependent on particle size and the number of nearby particles. Here we show that electrical breakdown of air is the primary cause of triboelectric charge saturation on single and multiple electrically insulating particles, which explains the inverse dependence of surface charge density on particle size and number of particles. We combine computational simulations with experiments under controlled humidity and pressure. The results show that the electric field contribution of multiple particles causes electrical breakdown of air, reducing saturation surface charge density for greater numbers of particles. Furthermore, these results show that particles can be discharged in a low pressure environment, yielding opportunities for improved industrial powder flows and dust mitigation from surfaces. [ABSTRACT FROM AUTHOR]

Contact electrification and triboelectric charging are areas of intense research. Despite their low ability to accept or donate electrons, polymer insulator based triboelectric nanogenerators have emerged as highly efficient mechanical‐to‐electrical conversion devices. Here, it is reviewed the structure–property–performance of polymer insulators in triboelectric nanogenerators and focus on tools that can be used to directly enhance charge generation, via altering a polymer's mechanical, thermal, chemical, and topographical properties. In addition to the discussion of these fundamental properties, the use of additives to locally manipulate the polymer surface structure is discussed. The link between each property and the underlying charging mechanism is discussed, in the context of both increasing surface charge and predicting the polarity of surface charge, and pathways to engineer triboelectric charging are highlighted. Key questions facing the field surrounding data reporting, the role of water, and synergy between mass, electron, and ion transfer mechanisms are highlighted with aspirational goals of a holistic model for triboelectric charging proposed. [ABSTRACT FROM AUTHOR]

A liquid metal (LM) soft sensors for strain monitoring and self‐powered tactile detection in soft robotics are developed. The sensor is fabricated by printing a bilayer of oxidized LM paste and bare LM on a soft substrate. This bilayer design overcomes the challenges in scalable printing of liquid metal and demonstrates soft sensors with exceptional electromechanical performance. Specifically, the sensor exhibits a strain sensing range of over 400% with a gauge factor of over 2, while displaying low hysteresis and high mechanical stability. Furthermore, the sensor utilizes a single electrode triboelectric effect to achieve self‐powered tactile sensing. To demonstrate the potential of these sensors in soft robotics, it is integrated into a soft pneumatic actuator and successfully demonstrate their ability to perceive gestures, motion, and grasping. This work highlights the potential of LM‐based soft sensors in advancing the field of soft sensing and soft robotics. [ABSTRACT FROM AUTHOR]

Graphdiyne (GDY), a new 2D material, has recently proven excellent performance in photodetector applications due to its direct bandgap and high mobility. Different from the zero‐gap of graphene, these preeminent properties made GDY emerge as a rising star for solving the bottleneck of graphene‐based inefficient heterojunction. Herein, a highly effective graphdiyne/molybdenum (GDY/MoS2) type‐II heterojunction in a charge separation is reported toward a high‐performance photodetector. Characterized by robust electron repulsion of alkyne‐rich skeleton, the GDY based junction facilitates the effective electron–hole pairs separation and transfer. This results in significant suppression of Auger recombination up to six times at the GDY/MoS2 interface compared with the pristine materials owing to an ultrafast hot hole transfer from MoS2 to GDY. GDY/MoS2 device demonstrates notable photovoltaic behavior with a short‐circuit current of −1.3 × 10−5 A and a large open‐circuit voltage of 0.23 V under visible irradiation. As a positive‐charge‐attracting magnet, under illumination, alkyne‐rich framework induces positive photogating effect on the neighboring MoS2, further enhancing photocurrent. Consequently, the device exhibits broadband detection (453–1064 nm) with a maximum responsivity of 78.5 A W−1 and a high speed of 50 µs. Results open up a new promising strategy using GDY toward effective junction for future optoelectronic applications. [ABSTRACT FROM AUTHOR]