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To bring the rapidly advancing technology of energy harvesters into commercial use, further development is required for devices that can enhance output performance, flexibility, ease of fabrication, and low cost. A hybrid concept is a promising method. It combines between the piezoelectric nanogenerator (PENG) and the triboelectric nanogenerator (TENG) to provide a high-performance nanogenerator. This study introduced a high-performance hybrid PENG and TENG device that operates using a NN-BNT/PDMS composite film. The NN-BNT/PDMS composite based nanogenerators were fabricated with varying NN-BNT content. Then, dielectric test and electrical properties were investigated. Adding NN-BNT into the PDMS composite film resulted in a higher dielectric constant compared to pure PDMS, leading to increase of electrical output. Under the optimal condition of a 3 wt%. NN-BNT composite based hybrid nanogenerator, the electrical output was significantly enhanced, reaching 40 V, 0.95 μA/cm2, and 200 μW/cm2 compared to pure PDMS. This nanogenerator further used to the charging of a capacitor to a voltage of around 1 V within 5 s and also powered multiple LEDs. The successful development of this highly efficient NN-BNT/PDMS composite film-based hybrid concept sheds light on energy harvesting devices. [ABSTRACT FROM AUTHOR]

Flow‐induced vibrations (FIVs) serve as the fundamental principle of non‐rotary wind energy harvesting. However, nanogenerators relying on a single FIV effect remain constrained by insufficient breeze energy conversion efficiency. In this paper, we propose a novel galloping‐flutter coupled nanogenerator (GFNG) that leverages the synergistic interaction between these two aerodynamic phenomena, to achieve high performance across broad wind speed bandwidth. A galloping‐flutter coupled mechanism (GFM) is implemented using a multifunctional flexible beam that integrates a galloping piezoelectric energy harvester (GPEH) and a fluttering triboelectric nanogenerator (FTENG). Through meticulous optimization, it significantly enhances the average electrical output of the FTENG by up to six times at low wind speeds below 6 m s−1, by intensifying the triboelectric contact behavior through galloping‐induced beam oscillations. The GFNG demonstrates a maximum average power of 6.3 mW across wind speeds from 1.4 to 10 m s−1, along with a remarkable power density of 7.1 W m−2 of the enhanced FTENG at 10 m s−1, enabling the lighting of 508 LEDs and stable power supply for wireless sensor nodes (WSNs). This study offers new insights into designing high‐performance aerodynamics‐driven nanogenerators by harnessing multiple FIV synergistic effects, broadening the potential for intelligent wind energy applications. [ABSTRACT FROM AUTHOR]

To mitigate the risks posed by noncommunicable chronic diseases (NCDs) to human health, the Internet of Healthcare (IoH) requires sensors with real‐time and long‐term monitoring capabilities. However, traditional pressure sensors, due to their high‐power consumption and non‐rechargeability, are unbale to meet the increasingly stringent requirements of physiological monitoring devices in the IoH. The emergence of self‐powered pressure sensing technology, exemplified by nanogenerators, provides a new strategy for the next generation of wearable health monitoring devices. This review begins by discussing the merits and drawbacks of different pressure‐sensing modes for healthcare monitoring. Then, it introduces the development and working mechanism of self‐powered triboelectric and piezoelectric sensors. Furthermore, it summarizes the optimizations of sensor structure and material selection aimed at improving sensing performance and achieving high accuracy in sensor networks within the IoH. Relevant application based on independent, or hybrid mechanisms are also covered. Finally, the challenges and prospects for achieving large‐scale commercial applications of self‐power sensing system in IoH are discussed. [ABSTRACT FROM AUTHOR]

In recent years, the automotive industry has made significant progress in integrating multifunctional sensors to improve vehicle performance, safety, and efficiency. As the number of integrated sensors keeps increasing, there is a growing interest in alternative energy sources. Specifically, self‐powered sensor systems based on energy harvesting are drawing much attention, with a main focus on sustainability and reducing reliance on typical batteries. This paper demonstrates the use of triboelectric nanogenerators (TENGs) in a computer mouse for efficient energy harvesting and in automobile braking systems for safety applications using SrBi2Ta2O9 (SBTO) perovskite, blended PDMS composite operating in free‐standing mode with an interdigitated patterned aluminum electrode. This self‐powered sensor is capable of distinguishing between normal and abnormal braking patterns using digital signal processing techniques. It is noteworthy that the addition of 15% wt. of the SBTO in PDMS composite‐based TENG delivered 13.5 V, 45 nA, and an output power of 0.98 µW. This new combination of energy harvesting and safety applications enables real‐time monitoring and predictive maintenance in the automotive industry. [ABSTRACT FROM AUTHOR]

Subhasmita Swain,1 RDK Misra,2 Tapash R Rautray1 1Biomaterials and Tissue Regeneration Laboratory, Centre of Excellence, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, Odisha, India; 2Metallurgical, Materials and Biomedical Engineering Department, The University of Texas at El Paso, El Paso, Texas, 79968, USACorrespondence: Tapash R Rautray; RDK Misra, Email tapashrautray@soa.ac.in; dmisra2@utep.eduAbstract: Electroactive components can promote tissue healing and control neuronal activity with the support of the tissue environment and offer electrical impulses and biocompatible material habitats. Due to the increasing growth of portable electronics, it is imperative to generate tiny, lightweight power supply appliances with outstanding performance and sustainable energy conversion ability. In order to deal with the energy deficiency of electronic devices, self-powered systems based nanogenerators are committed to capturing ambient energy for electronic device consumption. Nanogenerator assemblies provide a range of benefits, including adjustable shape, flexibility, affordability, and transportability. As such, they represent a novel and intriguing area for biomedical investigation. In living organisms, bioelectrical mechanisms play an integral part in regulating the functions of cells and tissues. An essential component of electroactive assemblies includes self-powered nanogenerators. In conjunction with nanogenerators, biomedicine has contributed to the invention of medical devices based on self-powered system. Currently, one of the most significant energy-based technologies to guarantee the long-term functioning of implanted biomedical devices is the accumulation of biomechanical energy in vivo. This review covers the development of nanogenerators for biomedical applications. Piezoelectric and triboelectric materials, which could foster the evolution of potential applications in the field of bone regeneration and tissue engineering, are the primary focus of this review. These materials are electrically self-sustaining generators that encourage tissue repair involving osteogenic proliferation, differentiation, and microbial sterilization. Eventually, the discussion highlights the potential future scope and challenges related to the nanogenerators.Keywords: nanogenerator, piezoelectric, triboelectric, tissue engineering

The rise of the Internet of things has catalyzed extensive research in the realm of flexible wearable sensors. In comparison with conventional sensor power supply methods that are reliant on external sources, self-powered sensors offer notable advantages in wearable comfort, device structure, and functional expansion. The energy-harvesting modes dominated by piezoelectric nanogenerators (PENGs), triboelectric nanogenerators (TENGs), and pyroelectric nanogenerators (PyENGs) create more possibilities for flexible self-powered sensors. This paper meticulously examines the progress in flexible self-powered devices harnessing TENG, PENG, and PyENG technologies and highlights the evolution of these sensors concerning the material selection, pioneering manufacturing techniques, and device architecture. It also focuses on the research progress of sensors with composite power generation modes. By amalgamating pivotal discoveries and emerging trends, this review not only furnishes a comprehensive portrayal of the present landscape but also accentuates avenues for future research and the application of flexible self-powered sensor technology.

Triboelectric nanogenerators (TENGs) hold immense potential as sustainable energy sources, with waste materials serving as promising materials for their fabrication. Nearly 270 million tons of waste is produced yearly, most of which remains unrecycled. TENGs can utilize this wide range of waste to convert mechanical energy to electrical energy while providing a solution for the global issue of plastic waste. On the other hand, the enormous demand for wearable electronics and the Internet of Things (IoT) trigger the development of self‐reliant energy sources. Currently, TENGs are one of the preferred choices as they are easy to design and generate high output. In this regard, TENGs are promising for utilizing waste materials, particularly for self‐powered or energy‐autonomous applications. This review focuses on utilizing waste materials from diverse sources, including biowaste, household waste, medical, laboratory, pharmaceutical, textile, electronic waste (e‐waste), and automotive waste for TENG development. Different waste materials are detailed for their potential as materials for TENGs, their availability, and recycling methods. The review also highlights the applications of TENGs fabricated from waste materials. Finally, the challenges, limitations, and future perspectives of using waste materials for TENG fabrication are discussed to motivate further advances. [ABSTRACT FROM AUTHOR]

The development of triboelectric nanogenerators (TENGs) using sustainable materials addresses the global electronic waste issue. This research focuses on fabricating a TENG device with biodegradable polylactic acid (PLA) as the tribopositive material and polytetrafluoroethylene (PTFE) as the tribonegative material. ZnFe2O4 nanoparticles are incorporated into the PLA matrix to enhance surface charge density and synthesised via a simple combustion method. PLA-ZnFe2O4 composite films were prepared by solvent casting with varying nanofiller content (0.25, 0.45, 0.65, and 0.85 g). Prepared composites were characterised by Powder X-ray Diffraction (PXRD) for crystalline nature and phase purity, Fourier Transform Infrared Spectroscopy (FTIR) for vibrational analysis, and Scanning Electron Microscopy (SEM) for surface morphology. The inclusion of ZnFe2O4 nanoparticles improves TENG output performance, with a maximum output voltage of 18.4 V and a current of 1.57 µA observed for a PLA (poly(lactic acid)) composite with 39.39% nanoparticle content. Electrical studies on the optimised device show successful charging of various capacitors and powering 20 LEDs and a calculator. Body movements like walking and jumping were also tested to measure voltage and current outputs. These findings highlight new possibilities for developing smart, self-powered electronic devices. [ABSTRACT FROM AUTHOR]

Hybrid nanogenerators are advanced mechanical energy harvesters capable of simultaneously scavenging multiple types of energy. Additionally, thermochromic materials provide a practical and visually assessable method for real‐time temperature monitoring. In this report, a novel energy harvester and sensing patch (EHSP) is introduced, that utilizes combined piezoelectric and triboelectric effects to harvest mechanical energy efficiently. To optimize the EHSP, various energy harvester configurations are fabricated and tested, and the dielectric properties of triboelectric films are systematically investigated. These improvements are implemented to augment the overall energy harvesting capability. The thermochromic properties of the EHSP are also explored to enhance both the electrical performance and thermal responsiveness. The EHSP demonstrates the ability to generate maximum voltage and current outputs of 350 V and 20.4 µA, respectively. Moreover, it can detect temperature changes within seconds, making it suitable for both energy harvesting and sensing applications. The EHSP is tested in practical scenarios, proving its efficiency as an energy harvester and sensor for everyday human activities. Furthermore, its integration with multiple hybrid nanogenerators showcases its potential for industrial and wearable sensing applications. [ABSTRACT FROM AUTHOR]

The rise of the Internet of things has catalyzed extensive research in the realm of flexible wearable sensors. In comparison with conventional sensor power supply methods that are reliant on external sources, self-powered sensors offer notable advantages in wearable comfort, device structure, and functional expansion. The energy-harvesting modes dominated by piezoelectric nanogenerators (PENGs), triboelectric nanogenerators (TENGs), and pyroelectric nanogenerators (PyENGs) create more possibilities for flexible self-powered sensors. This paper meticulously examines the progress in flexible self-powered devices harnessing TENG, PENG, and PyENG technologies and highlights the evolution of these sensors concerning the material selection, pioneering manufacturing techniques, and device architecture. It also focuses on the research progress of sensors with composite power generation modes. By amalgamating pivotal discoveries and emerging trends, this review not only furnishes a comprehensive portrayal of the present landscape but also accentuates avenues for future research and the application of flexible self-powered sensor technology. [ABSTRACT FROM AUTHOR]

Polystyrene (PS) is a very common material in packaging. In this study, it is recycled by turning it into energy harvesting devices: triboelectric generators. Herein, heat‐pressed films of recycled PS are formed and their surfaces are modified physically and chemically. The triboelectric properties of the films are determined using a dynamic testing machine, and the performance of the triboelectric generators is evaluated with a high‐speed contact–separation system. The developed charge density of the triboelectric generator increases two orders of magnitude—from 0.03 to 1.52 nC cm−2—by combining these surface modification methods. Such high values of charge density enable the production of single material triboelectric generators. [ABSTRACT FROM AUTHOR]

Wireless energy transfer (WET) based on ultrasound‐driven generators with enormous beneficial functions, is technologically in progress by the valuation of ultrasonic metamaterials (UMMs) in science and engineering domains. Indeed, novel metamaterial structures can develop the efficiency of mechanical and physical features of ultrasound energy receivers (US‐ETs), including ultrasound‐driven piezoelectric and triboelectric nanogenerators (US‐PENGs and US‐TENGs) for advantageous applications. This review article first summarizes the fundamentals, classification, and design engineering of UMMs after introducing ultrasound energy for WET technology. In addition to addressing using UMMs, the topical progress of innovative UMMs in US‐ETs is conceptually presented. Moreover, the advanced approaches of metamaterials are reported in the categorized applications of US‐PENGs and US‐TENGs. Finally, some current perspectives and encounters of UMMs in US‐ETs are offered. With this objective in mind, this review explores the potential revolution of reliable integrated energy transfer systems through the transformation of metamaterials into ultrasound‐driven active mediums for generators. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) have emerged as promising portable and sustainable energy sources in daily life, harvesting energy from human motion, water, and wind. However, they still face limitations in aspects such as contact area, deformability, wettability, and manufacturing method. Here, a wearable TENG incorporating an anisotropic domino structure based on a fluorinated elastomer blend is presented. Because of its thin, elongated structure with broad sides, the TENG achieves substantially larger contact areas and high bendability. Introducing a fluorinated elastomer into the polydimethylsiloxane matrix via a simple blending process not only enhances the triboelectric performance but also reduces surface energy and improves the stretchability of elastomers. The anisotropic arrangement of dominoes, in synergy with the fluorinated elastomer, mimics the surface physicochemical properties of natural rice leaves, resulting in anisotropic superhydrophobic wetting behavior with a self‐cleaning effect and controlled directional water flow for efficient water energy harvesting. Therefore, the TENG functions as an energy‐harvesting leaf that captures energy from wind and water droplets, as well as a wearable energy‐harvesting wristband that generates power from human motions such as touching, shaking, and hand washing. [ABSTRACT FROM AUTHOR]

Recent developments in robotics increasingly highlight the importance of sensing technology, especially tactile perception, in enabling robots to effectively engage with their environment and interpret physical interactions. Due to power efficiency and low cost, the triboelectric mechanism has been frequently studied for measuring pressure and identifying materials to enhance robot perception. Nevertheless, there has been limited exploration of using the triboelectric effect to detect curved surfaces, despite their prevalence in daily lives. Here, a triboelectric multimodal tactile sensor (TMTS) of multilayered structural design is proposed to recognize distinct materials, curvatures, and pressure simultaneously, thus decoupling different modalities to enable more accurate detection. By attaching sensors to robotic fingertips and leveraging deep learning analytics, the quantitative curvature measurement provides more precise insights into an object's detailed geometric characteristics rather than merely assessing its overall shape, hence achieving automatic recognition of 12 grasped objects with 99.2% accuracy. The sensor can be further used to accurately recognize the softness of objects under different touch gestures of a robotic hand, achieving a 94.1% accuracy, demonstrating its significant potential for wide‐ranging applications in a future robotic‐enabled intelligent society. [ABSTRACT FROM AUTHOR]

The porous structure formed by the interweaving of yarns in textiles is favorable for sound absorption. However, the absorption of sound waves by porous materials conforms to the law of linear response, which leads to poor sound absorption of textiles in the low-frequency range. It is usually necessary to increase the thickness to improve the low-frequency acoustic absorption performance of textiles, which does not meet the performance requirements of lightness, thinness, width and strength. This work proposes a method to increase the acoustic absorption performance based on acoustic-electric conversion and yarn resonance effect. In the form of a woven spacer fabric structure, different parts of the structure were prepared using nylon and PVDF yarns with different triboelectric sequences to realize acoustic-electric conversion between dielectric materials. Control samples woven with the same material were also prepared. Further, the resonance frequency of the yarns was modulated by controlling their tension to change the resonant frequency corresponding to the maximum acoustic-electric conversion efficiency and sound absorption peak. It was found that fabrics composed of two different materials had better sound absorption than fabrics composed of only one material. This is because the larger triboelectric sequence difference between materials results in more charge transfer, which favors acoustic-electric conversion and acoustic energy consumption. A significant acoustic absorption peak at 390 Hz with a peak value of about 0.05 was observed for a fabric with a thickness of about 4 mm after tension adjustment. This study demonstrates that acoustic-electric conversion between dielectric yarns and proper tension control improves the acoustic absorption efficiency and provides a reference for the development of structures based on this novel acoustic absorption mechanism. [ABSTRACT FROM AUTHOR]

Within electrical contacts, poor electrical conductivity of lubricants can lead to triboelectric charging, causing electrostatic currents and thermal effects, which accelerate lubrication failure. This study aimed to address these challenges by producing and testing three greases with different base oils: ionic liquid ([Oley][Oleic]), synthetic oil (PAO4), and vegetable oil-based synthetic ester (trimethylolpropane oleate). Each grease was prepared with polytetrafluoroethylene powder as the thickener. The greases were tested using a custom-made tribometer, integrated with a grounded electrical current system, with friction tests conducted with up to a 2 A electrical current flow at a constant voltage supply of 4.5 V. Under triboelectric friction testing, [Oley][Oleic] grease outperformed a commercial perfluoropolyether grease by 27.7% in friction and 16.3% in wear. This grease also showed better performance than formulated lithium grease with extreme pressure additives. The study demonstrates that greases with low interfacial resistance can retain their lubrication capacity under triboelectric conditions. These results indicate that [Oley][Oleic] grease, with its ionic liquid base oil, offers a promising solution for applications involving electrical contacts. This study highlights the potential of using advanced base oils and thickeners to enhance the performance and sustainability of lubricants in demanding environments. [ABSTRACT FROM AUTHOR]

Multi‐dimensional force sensing that combines intensity, location, area and the like could gather a wealth of information from mechanical stimuli. Developing materials with force‐induced optical and electrical dual responses would provide unique opportunities to multi‐dimensional force sensing, with electrical signals quantifying the force amplitude and the luminescence output providing spatial distribution of force. However, the reliance on external power supply and high‐energy excitation source brings significant challenges to the applicability of multi‐dimensional force sensors. Here we reported the mechanical energy‐driven and sunlight‐activated materials with force‐induced dual responses, and investigated the underlying mechanisms of self‐sustainable force sensing. Theoretical analysis and experimental data unraveled that trap‐controlled luminescence and interfacial electron transfer play a major role in force‐induced optical and electrical output. These materials were manufactured into pressure sensor with renewable dual‐mode output for quantifying and visualization of pressures by electrical and optical output, respectively, without power supply and high‐energy irradiation. The quantification of tactile sensation and stimuli localization of mice highlighted the multi‐dimensional sensing ability of the sensor. Overall, this self‐powered pressure sensor with multimodal output provides more modalities of force sensing, poised to change the way that intelligent devices sense with the world. [ABSTRACT FROM AUTHOR]

Developing energy harvesting devices is crucial to mitigate the dependence on conventional and rigid batteries in wearable electronics, ensuring their autonomous operation. Nanogenerators offer a cost‐effective solution for enabling continuous operation of wearable electronics. Herein, this study proposes a novel strategy that combines freeze‐casting, freeze‐drying, and printing technologies to fabricate a fully printed triboelectric nanogenerator (TENG) based on polyvinylidene fluorid‐etrifluoroethylene P(VDF‐TrFE) porous aerogel. First, the effects of porosity and poling on the stretchability and energy harvesting capabilities of P(VDF‐TrFE) are investigated, conducting a comprehensive analysis of this porous structure's impact on the mechanical, ferroelectric, and triboelectric properties compared to solid P(VDF‐TrFE) films. The results demonstrate that structural modification of P(VDF‐TrFE) significantly enhances stretchability increasing it from 7.7% (solid) to 66.4% (porous). This modification enhances output voltage by 66% and generated charges by 48% for non‐poled P(VDF‐TrFE) porous aerogel films compared to their non‐poled solid counterparts. Then, a fully printed TENG is demonstrated using stretchable materials, exhibiting a peak power of 62.8 mW m−2 and an average power of 9.9 mW m−2 over 100 tapping cycles at 0.75 Hz. It can illuminate light‐emitting diodes (LEDs) through the harvesting of mechanical energy from human motion. This study provides a significant advance in the development of energy harvesting devices. [ABSTRACT FROM AUTHOR]

The triboelectric effect has recently showcased significant potential in environmental remediation applications. It has been employed to initiate various catalytic reactions through the utilization of minimal mechanical energy. In this context, the present study focuses on the tribocatalytic activity of LiNbO 3 powder prepared via solid-state reaction process. From the study, it was found that ∼92 % of Rhodamine B (RB) dye was degraded in 15 h of mechanical stirring. The results showed that there is significant influence of each parameter in the tribocatalysis process. The current study systematically explored the connection between various affecting parameters and the tribocatalysis mechanism by using LiNbO 3 ceramic whereby laying a robust foundation for the advancement of tribocatalysis process. [ABSTRACT FROM AUTHOR]

Humans generate a lot of irregular movements in their daily lives, and much of the movement energy is difficult to collect. This paper develops a wearable device based on a liquid metal (LM)‐based frictional electric nanogenerator, including: flexible power‐generating fiber, power‐generating surface, and power‐generating insole. Friction nano power generation fibers are prepared using LM, epoxy resin, and silicone. The power generation device could be formed by weaving the fibers in cross, mesh and spiral arrangement, with a maximum open circuit voltage of 142 mV and current of 1.06 A, which could be coded into intelligent clothing. Power generating surfaces use LM, nylon,polycaprolactone (PCL), and polyethylene terephthalate (PET) as friction electrodes. The LM‐PCL produces a maximum open‐circuit voltage of 2.4 V and a maximum current of 1.23 A when they form a friction electrode. Electricity‐generating insoles are composed of silicone holes filled with LM, and the movement of the human foot generates electricity. With a friction area of 18.75 cm2, a maximum output voltage of 221 mV is obtained. These friction nano power devices have the advantages of a green environment, and low cost, which could be widely used in medical, biological, and clothing formulation fields. [ABSTRACT FROM AUTHOR]

Flexible piezoelectric nanogenerator (PENG) and triboelectric nanogenerators (TENG) have gained prodigious attention due to the increasing demand of nano and micro energy for driving of miniaturized electronic devices, sensors, and various internet of things. The key challenges that are currently in focus are material selection and simple fabrication techniques for improved electrical performance along with good mechanical properties and flexibility. Herein, a ferroelectric polymer, poly(vinylidenefluoride-co-trifluoroethyne) (PVDF-TrFE), is chosen as a flexible material due to its promising prospect for energy harvesting. To improve the performance, a ceramic material, 0.65Pb(Mg1/3Nb2/3)O3–0.35PbTiO3 (PMN-PT), with very high piezoelectric properties has been selected as the reinforcement. Further, reduced graphene oxide has been added as a conducting filler to promote charge conduction. A remarkable enhancement in output voltage of nearly 3 fold is achieved in PVDF-TrFE/PMN-PT (PP) polymer composite as compared to the base polymer PVDF-TrFE (P) TENG device. Furthermore, the PVDF-TrFE/rGO/PMN-PT (PPR) as a PENG illustrates a great improvement in output current of the order of 2 as compared to the pristine polymer. The maximum output voltage as shown by the TENG is 200 V and the maximum current that is shown by the PENG is 30 µA. Therefore, the fabricated PMN-PT based PVDF-TrFE nanogenerators have an immense prospect for applications in self-powered systems.

Abstract Wireless energy transfer (WET) based on ultrasound‐driven generators with enormous beneficial functions, is technologically in progress by the valuation of ultrasonic metamaterials (UMMs) in science and engineering domains. Indeed, novel metamaterial structures can develop the efficiency of mechanical and physical features of ultrasound energy receivers (US‐ETs), including ultrasound‐driven piezoelectric and triboelectric nanogenerators (US‐PENGs and US‐TENGs) for advantageous applications. This review article first summarizes the fundamentals, classification, and design engineering of UMMs after introducing ultrasound energy for WET technology. In addition to addressing using UMMs, the topical progress of innovative UMMs in US‐ETs is conceptually presented. Moreover, the advanced approaches of metamaterials are reported in the categorized applications of US‐PENGs and US‐TENGs. Finally, some current perspectives and encounters of UMMs in US‐ETs are offered. With this objective in mind, this review explores the potential revolution of reliable integrated energy transfer systems through the transformation of metamaterials into ultrasound‐driven active mediums for generators.

Abstract Kelvin probe force microscopy (KPFM) is a well‐established scanning probe technique, used to measure surface potential accurately; it has found extensive use in the study of a range of materials phenomena. In its conventional form, KPFM frustratingly precludes imaging samples or scenarios where large surface potential or surface potential gradients exist outside the typical ±10 V window. If the potential regime measurable via KPFM can be expanded, to enable precise and reliable metrology, through a high voltage KPFM (HV‐KPFM) adaptation, it can open up pathways toward a range of novel experiments, where the detection limit of regular KPFM has so far prevented the use of the technique. In this work, HV‐KPFM is realized and shown to be capable of measuring large surface potential and potential gradients with accuracy and precision. The technique is employed to study a range of materials (positive temperature coefficient of resistivity ceramics, charge storage fluoropolymers, and pyroelectrics) where accurate, spatially resolved mapping of surface potential within high voltage regime facilitates novel physical insight. The results demonstrate that HV‐KPFM can be used as an effective tool to fill in existing gaps in surface potential measurements while also opening routes for novel studies in materials physics.

Developing metal-free electrodes for prototypes of bio-based devices is an essential step in producing non-toxic components for implantable devices and wearables. In particular, the advancement in self-powered devices is a hot topic for several applications due to the possibility of creating free-battery devices and sensors. In this paper, the modification of bacterial cellulose by the progressive incorporation of carbon black (a conductive filler) was explored as a prototype for bio-based electrodes for triboelectric nanogenerators. This process was controlled by the percolation pathways’ activation through the contact of carbon black grains with the bacterial cellulose membrane, which represents a critical step in the overall process of optimization in the power output performance, reaching an open circuit voltage value of 102.3 V, short circuit current of 2 μA, and power density of 4.89 μW/cm2.

Developing metal-free electrodes for prototypes of bio-based devices is an essential step in producing non-toxic components for implantable devices and wearables. In particular, the advancement in self-powered devices is a hot topic for several applications due to the possibility of creating free-battery devices and sensors. In this paper, the modification of bacterial cellulose by the progressive incorporation of carbon black (a conductive filler) was explored as a prototype for bio-based electrodes for triboelectric nanogenerators. This process was controlled by the percolation pathways' activation through the contact of carbon black grains with the bacterial cellulose membrane, which represents a critical step in the overall process of optimization in the power output performance, reaching an open circuit voltage value of 102.3 V, short circuit current of 2 μA, and power density of 4.89 μW/cm2. [ABSTRACT FROM AUTHOR]

The ferroelectric‐semiconductor behavior of antimony sulfoiodide (SbSI) has opened up the material as a base for energy‐harvesting devices. Specifically, SbSI has drawn much attention for pyroelectric energy harvesting and thermal sensing with outstanding electrothermal properties. This work investigates the thermistor properties of an SbSI material and presents the development of an SbSI nanorod/Kapton‐based triboelectric nanogenerator (TENG) for effective energy harvesting and temperature sensing. The TENG based on SbSI/ Kapton operating in vertical contact separation mode delivers a peak‐to‐peak voltage of 90 V and a current of 1510 nA, respectively. Introducing SbSI nanorods for TENG opens the possibility of extending the conventional triboelectric series. The electrical and dielectric properties of the SbSI nanorods are investigated. SbSI exhibits a highly linear temperature coefficient of resistance (TCR) of −0.026 °C−1, making it an excellent candidate material for a thermistor. In addition, the material exhibits an excellent thermal sensitivity (β20/80 = 1612.1 K). For demonstration, the SbSI thermistor is connected with TENG, and the outputs at various temperatures are analyzed for self‐powered temperature sensing. This capability allows for efficient temperature monitoring without relying on external power sources, advancing remote, and autonomous sensing applications. [ABSTRACT FROM AUTHOR]

Harvesting the dissipated environmental mechanical energy to generate electrical energy is subject of the new research in the field of clean energy. In this paper, a triboelectric nanogenerator based on vertical two-electrode structure was fabricated using KAPTON and PDMS polymers. The nanogenerator outputs were measured and plotted by applying a mechanical vibration with the frequency of 8 Hz. The results indicated the ability of producing a voltage of 3.5 V and a current of 0.025 μA by this nanogenerator. To effectively simulate the performance of the device in different structural and environmental conditions, the ordinary capacitance model of the device was modified considering three effective capacitances. The simulation results showed a very good agreement between calculated and actual outputs when the edge effect capacitor was included in the ordinary model. Finally, based on the corrected model for the nanogenerator, the effect of the environmental conditions on the device output was studied. The innovative point of this text is the investigation of the effect of edge capacitors in the performance of triboelectric nanogenerators, and it has also been tried to collect a collection of studies that I have done in the field of triboelectric nanogenerators. [ABSTRACT FROM AUTHOR]

Energy harvesting systems, including piezoelectric (PENG), triboelectric (TENG), and pyroelectric (PYNG) nanogenerator technologies, have emerged as one of the major future energy solutions. Energy harvesting eliminates the need for conventional batteries and encourages eco-friendly alternatives. This study reports hydrothermally synthesized BaTiO3 (BTO) particles with a tetragonal symmetry for hybrid energy harvesting. BTO particles are incorporated with PDMS at various wt% to form a flexible composite film. The 15 wt% BTO-PDMS composite/Al hybrid device (PENG-TENG) produces a peak voltage of 100 V, a current of 980 nA, and a charge of 17 nC, generating a peak power output of 33.64 μW at 100 MΩ. Furthermore, integrating this HNG (external hybridization) yielded an output of 101 V and 980 nA, demonstrating practical applicability. HNG is also employed to interact by touching various objects at different temperatures. The pyroelectric behavior of BTO allows direct thermal sensing of the object. The signals produced are processed using a convolutional neural network (CNN)-based object recognition system, which achieved a remarkable classification accuracy of 99.27% for various objects. External hybridization improves energy efficiency, representing a huge step forward in sustainable technology applications. This research paves the way for developing hybrid energy harvesters and can be employed further for extremely precise battery-free object recognition systems. This unique hybrid nanogenerator, which combines pyroelectric, piezoelectric, and triboelectric components, represents a new method of self-powered object detection. External hybridization improves energy efficiency, representing a huge step forward in sustainable technology applications.

Within electrical contacts, poor electrical conductivity of lubricants can lead to triboelectric charging, causing electrostatic currents and thermal effects, which accelerate lubrication failure. This study aimed to address these challenges by producing and testing three greases with different base oils: ionic liquid ([Oley][Oleic]), synthetic oil (PAO4), and vegetable oil-based synthetic ester (trimethylolpropane oleate). Each grease was prepared with polytetrafluoroethylene powder as the thickener. The greases were tested using a custom-made tribometer, integrated with a grounded electrical current system, with friction tests conducted with up to a 2 A electrical current flow at a constant voltage supply of 4.5 V. Under triboelectric friction testing, [Oley][Oleic] grease outperformed a commercial perfluoropolyether grease by 27.7% in friction and 16.3% in wear. This grease also showed better performance than formulated lithium grease with extreme pressure additives. The study demonstrates that greases with low interfacial resistance can retain their lubrication capacity under triboelectric conditions. These results indicate that [Oley][Oleic] grease, with its ionic liquid base oil, offers a promising solution for applications involving electrical contacts. This study highlights the potential of using advanced base oils and thickeners to enhance the performance and sustainability of lubricants in demanding environments.

Benefiting from the widespread potential applications in the era of the Internet of Thing and metaverse, triboelectric and piezoelectric nanogenerators (TENG & PENG) have attracted considerably increasing attention. Their outstanding characteristics, such as self-powered ability, high output performance, integration compatibility, cost-effectiveness, simple configurations, and versatile operation modes, could effectively expand the lifetime of vastly distributed wearable, implantable, and environmental devices, eventually achieving self-sustainable, maintenance-free, and reliable systems. However, current triboelectric/piezoelectric based active (i.e. self-powered) sensors still encounter serious bottlenecks in continuous monitoring and multimodal applications due to their intrinsic limitations of monomodal kinetic response and discontinuous transient output. This work systematically summarizes and evaluates the recent research endeavors to address the above challenges, with detailed discussions on the challenge origins, designing strategies, device performance, and corresponding diverse applications. Finally, conclusions and outlook regarding the research gap in self-powered continuous multimodal monitoring systems are provided, proposing the necessity of future research development in this field.

Piezoelectric and triboelectric effects are of growing interest for facilitating high-sensitivity and self-powered tactile sensor applications. The working principles of piezoelectric and triboelectric nanogenerators provide strategies for enhancing output voltage signals to achieve high sensitivity. Increasing the piezoelectric constant and surface triboelectric charge density are key factors in this enhancement. Methods such as annealing processes, doping techniques, grain orientation controls, crystallinity controls, and composite structures can effectively enhance the piezoelectric constant. For increasing triboelectric output, surface plasma treatment, charge injection, microstructuring, control of dielectric constant, and structural modification are effective methods. The fabrication methods present significant opportunities in tactile sensor applications. This review article summarizes the overall piezoelectric and triboelectric fabrication processes from materials to device aspects. It highlights applications in pressure, touch, bending, texture, distance, and material recognition sensors. The conclusion section addresses challenges and research opportunities, such as limited flexibility, stretchability, decoupling from multi-stimuli, multifunctional sensors, and data processing.

Wearable energy harvesters (WEHs) have garnered significant attention recently due to their promising capabilities in powering wearable devices. In this research, we present a core–shell yarn-structured triboelectric nanogenerator (CY-TENG) that operates in two modes: the single-electrode TENG (SE-TENG) and the droplet-based electricity generator. This design facilitates energy harvesting from both waterdrops and biomechanics. The CY-TENG is fabricated using fluorinated ethylene propylene ultrafine heat-shrink tubes combined with stainless-steel yarns, ensuring its flexibility, durability, and weavability. Such attributes underscore its potential as a dual-function WEH.

A high-performance triboelectric nanogenerator (TENG) has been developed for breath sensing applications, utilizing tribopositive electrospun nylon-6 nanofibers and tribonegative fluorinated ethylene propylene (FEP). The optimization toward the development of electrospun nylon-6-based TENG includes a range of factors such as the applied force and frequency on tribo responses, the thickness of the fiber mat, the concentration of nylon-6 in the fiber mats, and the selection of the tribonegative material for pairing with nylon-6 nanofiber. Among these parameters, the nanofiber prepared with 18 wt% nylon-6, characterized by a uniform fiber distribution, the highest surface area of 55.69 m ^2 g ^−1 , and an optimal thickness of 0.169 mm, demonstrated excellent TENG performance, among others. The TENG module constructed using nanofiber in a 4 cm ^2 area showed the TENG responses of more than 30 μ A short-circuit current, 200 V open-circuit voltage, and 90 nC charge when hand-pressed. It achieved a substantial power density of 890 mW m ^−2 at 20 MΩ by applying a constant force of 10 N at a 10 Hz frequency. Charging a 1 μ F capacitor to approximately 30.1 V in just 30 s highlights the potential of electrospun nylon-6 as a promising material for nanogenerator energy harvesting and sensing applications. The TENG device was found to be sufficient to power small, portable electronics such as LEDs and digital watch displays. A wearable belt was fabricated to showcase its breath-sensing capabilities by pairing it with FEP. The microcontroller connected to the TENG in the wearable belt is used to analyze the output produced through breathing patterns, subsequently activating a buzzer and LED by the nature of the breathing.

• The doping level of PEDOT:PSS was modulated by ionic liquid additive. • Conductive polymer films with high doping levels exhibit high triboelectric properties. • An all-polymer based flexible self-powered triboelectric tactile sensor were fabricated. Triboelectric self-powered sensors, utilizing flexible conductive polymers in place of traditional metal electrodes, provide improved flexibility and reduced weight, making them highly promising for next-generation Internet of Things sensing applications. Here we demonstrate that ionic liquid (IL) additives notably enhance the mechanical and electrical properties of conductive polymer (PEDOT:PSS) films, optimizing their triboelectric performance. Results show that IL as molecular dopant induces structural change in PEDOT, thereby enhancing charge delocalization and doping levels. These IL-doped PEDOT:PSS films achieved high conductivity, significantly elevated surface potential, and a fourfold increase in output triboelectric voltage compared to the neat film. Additionally, flexible all-polymer tactile sensors with high sensitivity (3.6 V/kPa) were fabricated, demonstrating potential for diverse applications such as activity signal detection and human–machine interfaces. [ABSTRACT FROM AUTHOR]

Ocean energy is becoming increasingly important as a promising renewable energy source in modern society. Therefore, how to efficiently harvest ocean energy has attracted extensive research attention. In recent years, hybrid nanogenerators consisting of triboelectric and electromagnetic generators (TEHNGs), which compensate for the deficiency of energy conversion efficiency of single type generator, has been proposed and provided a promising way to harvest ocean energy effectively. Therefore, this review provides a comprehensive and in-depth analysis of TEHNGs from the structural design perspective. The characteristics including structural design, material selection, output performance, etc., of the four types TEHNGS are systematically summarized for the first time. The operating characteristics of TEHNGs with different structures in the ocean are elaborated in detail, as well as the significant influence of structural design on the output power of TEHNGs. In addition, the application scenario, environmental adaptability, and mutual assistance between TENG and EMG are discussed deeply. Finally, the existing challenges and development orientation in the aspects of structure design, materials, power management, durability and stability, and large-scale development, of the TEHNGs are put forward. It is believed that this work will be a significant reference for researchers in relevant field and conducive to the development of the TEHNGs in efficient ocean energy harvesting. [Display omitted] • Advances in ocean energy harvesting with TEHNG is comprehensively reviewed. • The output performance of TEHNGs with different structures are compared. • Hybridization of TENG and EMG is favorable in harvesting wave and current energy. • Challenges and perspectives of TEHNGs in ocean energy harvesting are presented. [ABSTRACT FROM AUTHOR]

[Display omitted] • Triboelectric and tribovoltaic effects of novel Cu x O-based nanogenerators are investigated. • Triboelectric series of Cu x O are adjusted by impurity and valence. • The Cu x O/NaCl(aq) tribovoltaic nanogenerators exhibit a high-power density of 4900 nW/cm2. • Relative positions of Fermi levels for various liquids are determined for the first time. • Rectifier/capacitor-free self-powered electroplating is demonstrated by solid–liquid tribovoltaic nanogenerators. Cu x O is a promising p-type semiconductor, but its triboelectric properties are unexplored. This study investigates both the triboelectric properties of Cu x O and the solid–liquid tribovoltaic effects between Cu x O and various liquids. Cu x O submicron rods are synthesized on Cu foams, doped with Li, and subjected to oxidant reactions. Li doping and valence changes increase Cu x O's work function, as shown by Kelvin probe force microscopy. Solid-solid triboelectric measurements reveal systematic changes in triboelectric voltage and current, with Cu x O negatively shifting in the triboelectric series. On the other hand, the Cu x O/liquid tribovoltaic effect conducted in an immersion-type device generates a stable direct current. The magnitudes of the tribovoltaic current and voltage systematically vary with the energy level differences between Cu x O and the liquids. From the direction of tribovoltaic current and magnitude of tribovoltaic voltage, the relative positions of fermi levels for several liquids are determined. Among all, the best Cu x O/NaCl (aq) tribovoltaic nanogenerators exhibit a high-power density of 4900 nW/cm2, and the generated DC is applied for novel rectifier/capacitor-free self-powered electroplating. This work demonstrates a viable method to adjust the triboelectric properties of Cu x O and proposes a method to determine the relative energy levels of liquids for the first time. [ABSTRACT FROM AUTHOR]

A screw transmission structure-based triboelectric-electromagnetic hybrid generator is developed, which can convert contact separation motion into continuous rotation. This device generates multiple pulse outputs during the compression and rebound processes. The generated electricity is 70.86 times greater than that of conventional contact-separation devices within one operating cycle, further improving the energy utilization efficiency and advancing its practical process. [Display omitted] • Designing a screw transmission structure-based hybridized generator. • Achieving a 70.86-fold increase in device's energy utilization efficiency. • Demonstrating a self-powered smart factory application based on ST-TEHG. Among various electromechanical conversion technologies, the triboelectric-electromagnetic hybrid generator (TEHG) stands out with its capacity to operate across a wider frequency range. Nevertheless, extracting more electricity from a single mechanical stimulation remains a significant challenge. In this work, we propose a screw transmission structure based TEHG (ST-TEHG) that converts the contact-separation motion into continuous rotation. This transformation enables the device to produce multiple pulse outputs in both compression and rebound processes. Specifically, the threaded barrel is designed to rotate continuously under the action of the pressing lever. Excess energy is stored as elastic potential energy in the tower spring, which then initiates the threaded barrel's reverse rotation upon the release of external force. Through systematical optimization of the screw transmission structure and device's performances, ST-TEHG achieves an energy utilization efficiency that is 70.86 times than the device with conventional contact-separation mode in an operating cycle. The developed ST-TEHG demonstrates promising applications in smart factories for indoor conditions monitoring, such as temperature and humidity, assembly line monitoring, and hazardous zones warning. This screw transmission structure sets a precedent for highly efficient mechanical energy harvesting, propelling the practical advancement of hybrid generators. [ABSTRACT FROM AUTHOR]

In recent years, receiver transducers have gained extensive attention in both research and industrial fields. In particular, the triboelectric receiver transducer (TE-RT) stands out due to their self-powered capability, low cost, and excellent output performance. While theoretical methods for analyzing the output performance are still lacked, which may limit the further development of this field. In this study, we propose an equivalent electromechanical conversion circuit that couples the acoustic field and electric field to predict the performance characteristics of the TE-RT. Specifically, the relationship between the deformation of the diaphragm and output performance of the TE-RT is analyzed through theoretical modeling and clarification of governing equations. Subsequently, a specific transformer revealing the mechanical-electrical conversion mechanism for the TE-RT was proposed using the equivalent circuit method (ECM), and an ECM model was established to analyze the performance of TE-RT quickly and accurately. To further improve the output performance of the TE-RT, piezoelectric materials are integrated into the model to enhance its capacity for converting acoustic energy. Verification for the two types of receiver transducer was conducted using the finite element method (FEM), and the equivalent circuit model fit the simulation results well. The acoustic energy conversion efficiency of the TE-RT can also be further evaluated by the number of turns (n) in the specialized transformer. This study can provide a solid theoretical foundation for the design and development of receiver transducer. [Display omitted] • Deformation of diaphragm & triboelectric transducer output analyzed via theoretical modeling. • Proposed a hybrid piezo/triboelectric transducer for improved output performance. • Proposed a special transformer for revealing mechanical-electrical conversion mechanism for the transducers. • Verification of transducers using FEM showed high model reliability. [ABSTRACT FROM AUTHOR]

Mechanoelectric energy conversion holds promise for energy conversion and transmission devices, yet conventional configurations rely on large-area conductive materials in active regions, limiting architectural design for cutting-edge devices. Here, a rational strategy is reported to create mechanical stimuli-driven pseudo-conductive (MSPC) channels entirely from dielectric materials, eliminating the need for electrodes in active regions. An in-depth investigation of MSPC channel formation mechanism at dielectric interfaces is conducted, employing energy band analyses. Following the mechanical stimuli-driven charging process, MSPC device effectively transmits electrical signals over 42 mm, achieving remarkable 512% enhancement compared to its pristine state. Control devices with non-continuous dielectric configurations highlight the impact of heterojunction interfaces on MSPC channels. A resistor-capacitor charging test reveals up to 49% reduction in voltage change rate, indicating a substantial decrease in electrical impedance along the MSPC channel. Furthermore, MSPC devices demonstrate information transmission capabilities, such as sequences of bits or letters, utilizing solely dielectric configurations. This study paves the way to reduce conductive materials of wearable electronics, biomedical implants, and IoT technologies, overcoming significant challenges such as potential electrical shortages, design inflexibility, limited manufacturing scalability, and maintenance issues., (© 2024 Wiley‐VCH GmbH.)

Mechano-bactericidal strategies represent a safe and sustainable method for preventing microbial contamination in the postantibiotic era. However, their effectiveness against Gram-positive bacteria (≤55%) is still limited due to the thick peptidoglycan layer in their cell walls. Herein, an intelligent biomimetic nanopillared biopatch is developed. It is assisted by low-voltage (8 V) electrical stimulation from TENG and significantly enhances antibacterial efficacy (>99%) against three types of stubborn Gram-positive bacteria. These collaborative antibacterial behaviors are solely based on purely physical actions, thus avoiding the risk of triggering bacterial resistance. Moreover, the slight mechanical energy generated by human physiological activities is converted into a power source, exhibiting energy-efficient, eco-friendly, and sustainable features. The conductive hydrogel in the biopatch can also act as an intelligent temperature sensor, monitoring, and real-time assessment of wound conditions. This intelligent biopatch holds immense potential for efficient healing and safe management of both acute and chronic wound infections.

In this study, we proposed a triboelectric nanogenerator (TENG) as a pressure sensor to measure the load imbalance on the tibial tray. To detect the load imbalance, we proposed a segmented quadrant design. The TENG pressure sensors with various micro-patterns, including pyramid, cylindrical, and bar patterns, are utilized to measure the axial forces with different sensitivity in different quadrants of the tibial tray. The functionality of the instrumented implant is examined through experimental testing on the package, evaluating its sensing capabilities and power harvesting. The relationship between each quadrant output and the axial force is determined, which enables characterizing the self-powered sensor performance. This relationship is then used to find the center of pressure, which is an important parameter for implant design. The detection of a shift in the center of pressure can be an early indication of loosening, which is one of the major causes of knee implant failure. In addition, we investigated the apparent power captured in resistance loads by applying a sinusoidal cyclic loading to the package harvester. Under an average walking load of 2200 N, each quadrant of the harvester-package prototype produces an apparent power of approximately 5 μ W at 1 Hz and 10 μ W at 2 Hz.

In low-dimensional material systems, augmented physical and chemical properties may be witnessed through a unique morphological evolution. Here, we report the development of an optimized nanowall network of ZnO for the fabrication of a flexible single-electrode triboelectric nanogenerator (STENG)-based tactile and gesture sensors. The chemically grown nanowall network with an adequate pore area endows superior triboelectric output (current ∼0.6 μA and power ∼20 μW/cm 2 ) by offering an optimum surface area and dielectric constant for pressure sensing applications. The rational comparison of the triboelectric properties of nanowall and nanorod structures of ZnO reveals that the higher surface area offered by the hollow walls leads to superior output characteristics. The demonstration of pressure sensitivity of the STENG ∼1 V/N is promising for self-powered tactile sensing applications. The array of STENG sensors, when attached to a user hand, generates distinguishable signals while holding objects of varying curvature and mass. Again, the observation of sensitivity of ∼0.1 V per degree during finger movement activity indicates the gesture sensing ability of the nanowall-based TENG system, facilitating sign language expression through the movement of fingers. Further, the generated electrical signals during tactile and gesture sensing can be classified and recognized through the deployment of machine learning (ML) techniques. In fact, the implementation of Random Forest and K-Nearest Neighbor models has offered an accuracy of 96% while recognizing the output signals generated by the sensor arrays. The demonstration of superior sensing characteristics with the optimized nanowall network may be advantageous in innovating prototype sensors for the differently abled people to distinguish or classify objects on the basis of material, morphology, and mass during their regular activities.

Acoustic sensor-based human-machine interaction (HMI) plays a crucial role in natural and efficient communication in intelligent robots. However, accurately identifying and tracking omnidirectional sound sources, especially in noisy environments still remains a notable challenge. Here, a self-powered triboelectric stereo acoustic sensor (SAS) with omnidirectional sound recognition and tracking capabilities by a 3D structure configuration is presented. The SAS incorporates a porous vibrating film with high electron affinity and low Young's modulus, resulting in high sensitivity (3172.9 mV pp Pa -1 ) and a wide frequency response range (100-20 000 Hz). By utilizing its omnidirectional sound recognition capability and adjustable resonant frequency feature, the SAS can precisely identify the desired audio signal with an average deep learning accuracy of 98%, even in noisy environments. Moreover, the SAS can simultaneously recognize multiple individuals in the auxiliary conference system and the driving commands under background music in self-driving vehicles, which marks a notable advance in voice-based HMI systems., (© 2024 Wiley‐VCH GmbH.)

The self-powered triboelectric touch panel has garnered considerable research attention due to its potential to reduce system energy consumption and its applications in human-machine interfaces, e-skin, and the Internet of Things. Current methods for achieving triboelectric-based touch positioning in an M × N detection pixel array typically require signal amplitude comparison across at least M + N signal channels, thereby limiting lightweight design possibilities. In contrast, our novel "resistor ladder" approach necessitates only 4 signal channels for touch positioning. This method leverages a lookup table correlating touch positions with amplitude ratios from different channels, rendering it insensitive to signal amplitude and significantly enhancing robustness. We fabricated a transparent touch panel using PET tribomaterial, where the surface roughness was enhanced through plasma treatment. The panel successfully demonstrated touch positioning for 128 taps within a 4 × 4 pixel detection array and sliding positioning using a predefined lookup table. To further enhance device robustness, a 2D convolutional neural network was implemented, which achieved an impressive touch positioning accuracy of 97.7% even under artificially introduced signal defects. This study represents an initial exploration of amplitude-insensitive touch and sliding positioning methods, significantly reducing the number of required signal channels and enhancing the robustness of triboelectric touch panels.

Biosensors have emerged as vital tools for the detection and monitoring of essential biological information. However, their efficiency is often constrained by limitations in the power supply. To address this challenge, energy harvesting systems have gained prominence. These off-grid, independent systems harness energy from the surrounding environment, providing a sustainable solution for powering biosensors autonomously. This continuous power source overcomes critical constraints, ensuring uninterrupted operation and seamless data collection. In this article, a comprehensive review of recent literature on energy harvesting-based biosensors is presented. Various techniques and technologies are critically examined, including optical, mechanical, thermal, and wireless power transfer, focusing on their applications and optimization. Furthermore, the immense potential of these energy harvesting-driven biosensors is highlighted across diverse fields, such as medicine, environmental surveillance, and biosignal analysis. By exploring the integration of energy harvesting systems, this review underscores their pivotal role in advancing biosensor technology. These innovations promise improved efficiency, reduced environmental impact, and broader applicability, marking significant progress in the field of biosensors., (© 2024 Wiley‐VCH GmbH.)

[Display omitted] • Fabricated a high-performance triboelectric nanogenerator (TENG) using a robust Nylon 6/functionalized MWCNTs nanocomposite. • Developed the nanocomposite via a customized convergent nozzle-driven melt-mixing process. • High mechanical properties were obtained at only 1 wt% of MWCNTs. • Achieved impressive TENG output: 105.7 V voltage, 10.55 μA current, and 465 mW/m2 power density. • Illuminated 128 LEDs by simple hand pressing on the TENG device, indicating its self-power capability for wearables. To meet the growing demand for durable, tough, and electrically conductive polymer nanocomposites driven by the rise of smart devices, e-textiles, wearables, and advanced structures, this study offers a systematic approach to fabricating highly robust Nylon 6/multi-walled carbon nanotubes (MWCNTs) nanocomposite films and fibers. The robustness of the nanocomposite is achieved through a simple straightforward approach involving the selective surface functionalization of MWCNTs with oxygen plasma-assisted tetraethylenepentamine grafting (O 2 T-MWCNTs) and melt-blending these MWCNTs with Nylon 6 under optimized conditions. The mixture is then processed through a specially designed narrow convergent nozzle attached to the extruder die. The die facilitates the alignment of the CNTs into the matrix in the flow direction and increases the composite strength. The incorporation of just 1 wt% of O 2 T-MWCNTs into Nylon 6 results in a nanocomposite with a remarkable enhancement, demonstrating a 93.25 % increase in tensile strength (T.S.), a 50.47 % increase in Young's Modulus (E), and an outstanding 136 % increase in elongation at the break (ε) compared to neat Nylon 6, surpassing contemporary benchmarks. Importantly, this method yields a nanocomposite ∼ 30.2 % stronger than the conventional melt-blending process without a nozzle. When fabricating a triboelectric nanogenerator (TENG) with the nanocomposite, exceptional performance was observed, with an output voltage of 105.7 V, a current of 10.55 μA, and a power density of 465 mW/m2, surpassing many reported values. Moreover, the TENG displays highly stable performance through 20,000 cycles of continuous compression. The nanogenerator also exhibited outstanding capability in harvesting mechanical energy from body movements, as demonstrated by lighting various LEDs and small electronics. [ABSTRACT FROM AUTHOR]

Recent advancements in energy harvesting have led to innovative methods for converting droplet motion into electricity, such as droplet triboelectric nanogenerators (D-TENGs). However, enhancing their power generation capacity and efficiency remains a challenge. We present a novel surface engineering approach that significantly boosts the electrical outputs of the D-TENGs. By grafting perfluorodecyltrimethoxysilane (PFDTMS) onto polydimethylsiloxane (PDMS) surfaces pre-treated with sandpaper, we achieve a dual effect: fluoridation and increased contact area between droplets and PDMS. This modification, when applied to a droplet-based TENG, yields a remarkable 10–20 fold increase in power metrics such as current, charge, and voltage as compared to untreated counterparts, resulting in an energy conversion efficiency of 17.1% under a 30 MΩ load. Our enhanced D-TENG efficiently harvested energy from falling tap water droplets, producing a current of ∼2 mA. Remarkably, a single droplet impact could illuminate 400 LED lights. Furthermore, when coupled with capacitors, the device powered a hygrometer and 3 W light bulbs, demonstrating substantial potential for real-world applications. This breakthrough in surface engineering for energy harvesters represents a significant step forward in the efficient and powerful generation of electricity from droplet motions. [Display omitted] • High performance device harvests energy from droplets. • Improved device performance achieved through surface engineering. • The impact of a single tap water droplet can generate a current exceeding 2 mA. • An energy conversion efficiency of 17.1% is achieved under a 30 MΩ load. • A single droplet impact can illuminate up to 400 LED lights. [ABSTRACT FROM AUTHOR]

Triboelectricity in materials has emerged as an innovative and increasingly researched approach for acoustic sensing. Despite its promise, the field has faced significant challenges due to limited working bandwidth and sensitivity. As a result, we have developed a dual-symmetry triboelectric acoustic sensor (DS-TAS), featuring an expansive working bandwidth from 20 Hz to 200 kHz, exceptional sensitivity of 6.67 V/Pa, and a detection limit as low as 0.002 Pa. Moreover, the DS-TAS has been successfully integrated into a real-time, multi-directional ultrasonic radar system, achieving an impressively minimal detection error of less than 5 mm. This breakthrough in acoustic sensing performance positions the DS-TAS as a significant milestone for the field, with broad applications ranging from human-machine interaction to voice recognition. [Display omitted] • The sensor demonstrates a multifaceted performance spectrum. • It holds a remarkable sensitivity of 6.67 V/Pa with a wide sensing range of 0.002 Pa to 0.02 Pa. • A real-time multidirectional ultrasonic radar localization scanning system has been developed. [ABSTRACT FROM AUTHOR]