Search Results (281)

Ocean energy is an abundant, eco-friendly, and renewable energy resource that is useful for powering sensor networks connected to the maritime Internet of Things (MIoT). These sensor networks can be used to measure different marine environmental parameters that affect ocean infrastructure integrity and harm marine ecosystems. This ocean energy can be harnessed through hybrid nanogenerators that combine triboelectric nanogenerators, electromagnetic generators, piezoelectric nanogenerators, and pyroelectric generators. These nanogenerators have advantages such as high-power density, robust design, easy operating principle, and cost-effective fabrication. However, the performance of these nanogenerators can be affected by the wear of their main components, reduction of wave frequency and amplitude, extreme corrosion, and sea storms. To address these challenges, future research on hybrid nanogenerators must improve their mechanical strength, including materials and packages with anti-corrosion coatings. Herein, we present recent advances in the performance of different hybrid nanogenerators to harvest ocean energy, including various transduction mechanisms. Furthermore, this review reports potential applications of hybrid nanogenerators to power devices in marine infrastructure or serve as self-powered MIoT monitoring sensor networks. This review discusses key challenges that must be addressed to achieve the commercial success of these nanogenerators, regarding design strategies with advanced simulation models or digital twins. Also, these strategies must incorporate new materials that improve the performance, reliability, and integration of future nanogenerator array systems. Thus, optimized hybrid nanogenerators can represent a promising technology for ocean energy harvesting with application in the maritime industry. Full article

Sign language recognition plays a crucial role in enabling communication for deaf individuals, yet current methods face limitations such as sensitivity to lighting conditions, occlusions, and lack of adaptability in diverse environments. This study presents a wearable multi-channel tactile sensing system based on smart textiles, designed to capture subtle wrist and finger motions for static sign language recognition. The system leverages triboelectric yarns sewn into gloves and sleeves to construct a skin-conformal tactile sensor array, capable of detecting biomechanical interactions through contact and deformation. Unlike vision-based approaches, the proposed sensor platform operates independently of environmental lighting or occlusions, offering reliable performance in diverse conditions. Experimental validation on American Sign Language letter gestures demonstrates that the proposed system achieves high signal clarity after customized filtering, leading to a classification accuracy of 94.66%. Experimental results show effective recognition of complex gestures, highlighting the system’s potential for broader applications in human-computer interaction. Full article

Electrospun nanofiber-based triboelectric nanogenerators (TENGs) have emerged as a highly promising class of self-powered sensors for a broad range of applications, particularly in intelligent sensing technologies. By combining the advantages of electrospinning and triboelectric nanogenerators, these sensors offer superior characteristics such as high sensitivity, mechanical flexibility, lightweight structure, and biocompatibility, enabling their integration into wearable electronics and biomedical interfaces. This review presents a comprehensive overview of recent progress in electrospun nanofiber-based TENGs, covering their working principles, operating modes, and material composition. Both pure polymer and composite nanofibers are discussed, along with various electrospinning techniques that enable control over morphology and performance at the nanoscale. We explore their practical implementations in both contact-type and non-contact-type sensing, such as human–machine interaction, physiological signal monitoring, gesture recognition, and voice detection. These applications demonstrate the potential of TENGs to enable intelligent, low-power, and real-time sensing systems. Furthermore, this paper points out critical challenges and future directions, including durability under long-term operation, scalable and cost-effective fabrication, and seamless integration with wireless communication and artificial intelligence technologies. With ongoing advancements in nanomaterials, fabrication techniques, and system-level integration, electrospun nanofiber-based TENGs are expected to play a pivotal role in shaping the next generation of self-powered, intelligent sensing platforms across diverse fields such as healthcare, environmental monitoring, robotics, and smart wearable systems. Full article

Contact electrification (CE), or triboelectrification, is an electron transfer phenomenon occurring at the interface between dissimilar materials due to differences in polarity, holding significant research value in tribology. The microscopic mechanisms of CE remain unclear due to the complex coupling of multiple physical processes. Recently, with the rise of triboelectric nanogenerator (TENG) technology, solid–liquid contact electrification has demonstrated vast application potential, sparking considerable interest in its underlying mechanisms. Emerging experimental evidence indicates that at water–polymer CE interfaces, the process involves not only traditional ion adsorption but also electron transfer. Halogen-containing functional groups in the solid material significantly enhance the CE effect. To elucidate the microscopic mechanism of water–polymer CE, this study employed first-principles density functional theory (DFT) calculations, simulating the interfacial electrification process using unit cell models of water contacting polymers. We systematically and quantitatively investigated the charge transfer characteristics at interfaces between water and three representative polymers with similar backbones but different halogen-functionalized (F, Cl) side chains: fluorinated ethylene propylene (FEP), polyvinyl chloride (PVC), and polytetrafluoroethylene (PTFE), focusing on evaluating halogen’s influence and mechanism on interfacial electron transfer. The results reveal that electron transfer is primarily governed by the energy levels of the polymer’s lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO). Halogen functional groups modulate the material’s electron-donating/accepting capabilities by altering these frontier orbital energy levels. Consequently, we propose that the critical strategy for polymer chemical modification resides in lowering the LUMO energy level of electron-accepting materials. This study provides a novel theoretical insight into the charge transfer mechanism at solid–liquid interfaces, offers guidance for designing high-performance TENG interfacial materials, and holds significant importance for both the fundamental theory and the development of advanced energy devices. Full article

Chitosan films with potential application in triboelectric nanogenerators (TENGs) represent a promising approach to replace non-biobased materials in these innovative devices. In the present work, chitosan with varying molecular weights (MW) and degrees of deacetylation was dissolved in aqueous acetic acid (AA) at different acid concentrations. It was observed that the MW had a greater influence on the viscosity of the solution compared to either the acid concentration or deacetylation degree. Gel formation occurred in high-MW chitosan solutions prepared with low AA concentration. Films prepared from chitosan solutions, through solvent-casting, were used to prepare TENGs. The power output of the TENGs increased with higher concentrations of AA used in the chitosan dissolution process. Similarly, the residual AA content in the dried films also increased with higher initial AA concentrations. Additionally, hot-pressing of the films significantly improves the TENG power output due to the decrease in morphological defects of the films. It was demonstrated that a good selection of the acid concentration not only facilitates the dissolution of chitosan but also plays a key role in defining the properties of the resulting solutions and films, thereby directly impacting the performance of the TENGs. Full article

This review systematically examines recent advances in self-powered wireless sensing technologies based on triboelectric nanogenerators (TENGs), focusing on innovative methods that leverage breakdown discharge effects to achieve high-precision and long-distance signal transmission. These methods offer novel technical pathways and theoretical frameworks for next-generation wireless sensing systems. To address the core limitations of conventional wireless sensors, such as a restricted transmission range, high power consumption, and suboptimal integration, this analysis elucidates the mechanism of the generation of high-frequency electromagnetic waves through localized electric field ionization induced by breakdown discharge. Key research directions are synthesized to enhance TENG-based sensing capabilities, including novel device architectures, the optimization of RLC circuit models, the integration of machine learning algorithms, and power management strategies. While current breakdown discharge sensors face challenges such as energy dissipation, multimodal coupling complexity, and signal interpretation barriers, future breakthroughs in material engineering and structural design are anticipated to drive advancements in efficiency, miniaturization, and intelligent functionality in this field. Full article

With the rapid rise in Internet of Things (IoT) and artificial intelligence (AI) technologies, there is an increasing need for portable, wearable, and self-powered flexible sensing devices. In such scenarios, self-powered nanogenerators have emerged as promising energy harvesters capable of converting ambient mechanical stimuli into electrical energy, enabling the development of autonomous flexible sensors and sustainable systems. This review highlights recent advances in nanogenerator technologies—particularly those based on piezoelectric and triboelectric effects—with a focus on soft, flexible, and gel-based polymer materials. Key mechanisms of energy conversion are discussed alongside strategies to enhance performance through material innovation, structural design, and device integration. Special attention is given to the role of gel-type composites, which offer unique advantages such as mechanical tunability, self-healing ability, and biocompatibility, making them highly suitable for next-generation wearable, biomedical, and environmental sensing applications. We also explore the evolving landscape of energy applications, from microscale sensors to large-area systems, and identify critical challenges and opportunities for future research. By synthesizing progress across materials, mechanisms, and application domains, this review aims to guide the rational design of high-performance, sustainable nanogenerators for the next era of energy technologies. Full article

Since 2015, research on liquid–solid triboelectric nanogenerators (L-S TENGs) has shown steady growth, with the primary focus on application domains such as engineering, physics, materials science, and chemistry. These applications have underscored the significant attention L-S TENGs have garnered in areas like human–nature interaction, energy harvesting, data sensing, and enhancing living conditions. Presently, doping composite dielectric materials and surface modification techniques are the predominant methods for improving the power generation capacity of TENGs, particularly L-S TENGs. However, studies exploring the combined effects of these two approaches to enhance the power generation capacity of TENGs remain relatively scarce. Following a review of existing literature on the use of composite material doping and surface modification to improve the power generation performance of L-S TENGs, this paper proposes an experimental framework termed “self-assembled surface TENG@carbonyl iron particle doping (SAS-TENG@CIP)” to investigate the integrated power generation effects of L-S TENGs when combining these two methods. Research cases and data results indicate that, for TENGs exhibiting capacitor-like properties, the enhancement of power generation performance through composite material doping and superhydrophobic surface modification is not limitless. Each process possesses its own inherent threshold. When these thresholds are surpassed, the percolation of current induced by material doping and electrostatic breakdown (EB) triggered by surface modification can lead to a notable decline in the power output capacity of L-S TENGs. Consequently, in practical applications moving forward, fully realizing the synergistic potential of these methods necessitates a profound understanding of the underlying scientific mechanisms. The conclusions and insights presented in this paper may facilitate their complex integration and contribute to enhancing power generation efficiency in future research. Full article

Poly(dimethylsiloxane) (PDMS) is a predominantly utilized negative triboelectric material in triboelectric nanogenerators (TENGs). Its surface topography and synergistic interaction with positive triboelectric materials significantly impact the performance of TENGs. Here, we propose a simple and cost-effective approach to promote the performance of a dual-surface-modified TENG using microwave-structured aluminum (MW-Al) together with microcone-structured polydimethylsiloxane (MC-PDMS). Laser-engraved molds were employed to cold-imprint the MC-Al and pattern the MC-PDMS. Subsequently, the impact of the heights of microcones generated under varying laser powers on the performance of TENGs was explored. The output performance of the MW-MC-TENG significantly increased with microcone heights from 0 to 228 μm. The MW-MC228-TENG, with the highest cone heights, can produce the best open-circuit voltage of 157 V and a short-circuit current of 78.5 µA, resulting in a more than 37% improvement compared to the TENG using flat polymer. Furthermore, the MW-MC228-TENG showed a power density of 16.4 W/m², sufficient to power 198 LEDs. Finally, the proposed TENG was integrated as a sensor into an impact warning system. We triggered a voice–visual warning when the TENG impacted, proving its potential for intelligent home safety monitoring. Full article

Triboelectric nanogenerators have attracted extensive attention as they can complete sensing during energy conversion, triggering a series of self-powered designs. Traditional TENG bipolar independent fabrication technology requires secondary motion control, which limits its application scenarios. In this work, we propose a flag-type TENG prepared using in situ electrospinning technology, in which the connecting region is obtained by electrospinning deposition of PVDF on nylon as the receiving electrode. The active area is isolated with silicone oil paper. After electrospinning, the silicone oil paper was removed, and the distance between the nylon and PVDF is far beyond the van der Waals range. Thus, contact separation can be effectively carried out under the action of wind. The device has been proven to be able to be used for monitoring wind conditions at high-speed rail stations and enables completely self-powered monitoring of the wind level using self-powered LED coding. The device no longer relies on additional batteries or wires to work, providing additional ideas for future self-powered system design. Full article

This study proposes a novel capacitor-based energy representation model for triboelectric nanogenerators (TENGs). Using this model, the energy conversion behavior of contact–separation-mode TENGs (CS-TENGs) is analyzed with particular attention to their inherent dual-capacitor structure. According to the relationship of high-voltage and high-energy output characteristics of CS-TENGs, a specialized energy harvesting circuit is designed, featuring a dual high-voltage switch that enables bidirectional charge transfer and efficient electromagnetic energy conversion. This switch forms the core of a new rectifier bridge and energy storage topology optimized for intermittent mechanical inputs. Experimental results confirm the validity of the proposed energy model and demonstrate that the developed topology significantly enhances energy harvesting and storage efficiency. The integration of theoretical modeling with circuit innovation offers a comprehensive and effective strategy for improving the electrical performance of CS-TENG systems. This work bridges the theoretical gap in dual-capacitor modeling with a practical rectifier design, offering an integrated solution for real-world TENG energy harvesting challenges. Full article

Cellulose nanofibril (CNF) is a sort of novel nanomaterial directly extracted from plant resources, inheriting the advantages of cellulose as a cheap, green and renewable material for the development of new-generation eco-friendly electronics. In recent years, CNF-based triboelectric nanogenerator (TENG) has attracted increasing research interests, as the unique chemical, morphological, and electrical properties of CNF render the device with considerable flexibility, mechanical strength, and triboelectric output. In this study, we explore the use of isoreticular metal-organic frameworks (IRMOF) as functional filler to improve the performance of CNF based TENGs. Two types of IRMOFs that own the same network topology, namely IRMOF-1 and its aminated version IRMOF-3, are embedded with CNF to fabricated TENGs; their contribution to triboelectric output enhancement, including the roughness effect induced by large particles as well as the charge induction effect arisen from -NH₂ groups, are discussed. The performance-enhanced CNF-based TENG with 0.6 wt.% of IRMOF-3 is utilized to harvest mechanical energy from human activities and charge commercial capacitors, from which the electrical energy is sufficient to light up light-emitting diodes (LEDs) and drive low-power electronic devices. In addition, a locomotor analysis system is established by assembling the above TENGs and capacitors into a 3 × 3 sensing array, which allowed signal extraction from each sensing unit to display a motion distribution map. These results demonstrate the great potential of CNF/IRMOF-based TENGs for development of self-powered sensing devices for long-term motion monitoring. Full article

Electrospinning techniques have been widely applied in diverse applications, such as biocompatible membranes, energy storage systems, and triboelectric nanogenerators (TENGs), with the capability to incorporate other functional materials to achieve specific purposes. Recently, gas sensors incorporating doped semiconducting materials fabricated by electrospinning have been extensively investigated. TENGs, functioning as self-powered energy sources, have been utilized to drive gas sensors without external power supplies. Herein, a self-powered triboelectric ethanol sensor (TEES) is fabricated by integrating a TENG and an ethanol gas sensor into a single device. The proposed TEES exhibits a significantly improved response time and lower detection limit compared to published integrated triboelectric sensors. The device achieves an open-circuit voltage of 51.24 V at 800 rpm and a maximum short-circuit current of 7.94 μA at 800 rpm. Owing to the non-contact freestanding operating mode, the TEES shows no significant degradation after 240,000 operational cycles. Compared with previous studies that integrated TENGs and ethanol sensors, the proposed TEES demonstrated a marked improvement in sensing performance, with a faster response time (6 s at 1000 ppm) and a lower limit of detection (10 ppm). Furthermore, ethanol detection is enabled by modulating the gate terminal of an IRF840 metal-oxide semiconductor field-effect transistor (MOSFET), which controls the illumination of a light-emitting diode (LED). The LED is extinguished when the electrical output decreases below the setting value, allowing for the discrimination of intoxicated states. These results suggest that the TEES provides a promising platform for self-powered, high-performance ethanol sensing. Full article

A triboelectric nanogenerator (TENG) holds significant potential as a self-powered pressure sensor due to its ability to convert mechanical energy into electrical energy. The output voltage of a TENG is directly correlated with the applied pressure, making it highly suitable for pressure sensing applications. Among the key factors influencing TENG performance, the microstructure on the surface plays a crucial role. However, the effect of surface microstructure on charge transfer behavior remains relatively underexplored. Here, a stripe-patterned rough TENG (SR-TENG) fabricated by laser ablation and molding is proposed. The stripe-patterned rough surface exhibits excellent deformation properties, allowing for more effective contact area between the tribolayers. Additionally, the localized surface-edge enhanced electric field at the stripe boundaries improves surface charge transfer, thereby enhancing overall output performance. The SR-TENG achieved an open-circuit voltage of 97 V, a short-circuit current of 59.6 μA, an instantaneous power of 3.55 mW, and a power density of 1.54 W/m². As an energy harvester, the SR-TENG successfully powered 150 LEDs. A linear relationship between applied pressure and output voltage was established with a coefficient of determination R² = 0.94, demonstrating a high sensitivity of 14.14 V/kPa. For practical application, a novel self-powered two-digit pressure switch was developed based on the SR-TENG. This system enables the control of two different LEDs using a single TENG device, triggered by applying a light or hard press. Full article

In recent years, technologies in the field of gait monitoring, such as gait parameter analysis, health monitoring, and medical diagnosis, have become increasingly mature. Gait monitoring technology has emerged as an effective means for disease prevention and diagnosis. Triboelectric nanogenerator technology not only overcomes the limitations of relying on external power sources and frequent battery replacements but also offers advantages such as low cost, lightweight, a wide range of material options, and ease of manufacturing. This review introduces the common working modes of triboelectric nanogenerators and summarizes recent advances in self-powered gait monitoring applications (e.g., gait analysis, fall detection, rehabilitation assessment, and identity recognition), and highlights persistent challenges such as wearability, washability of fabric-based devices, reliability, system integration, and miniaturization, along with proposed solutions. Full article