Triboelectric Nanogenerator Research Articles

Wearable broadband MoS2 photodetector for dual heart rate and UV detection powered by PDMS-MXene TENG

Wearable electronic devices capable of monitoring health parameters and environmental factors are tremendously desirable. Environmental energy harvesting as a power source is crucial to replace traditional batteries. This study aims to contribute to the development of sustainable and efficient wearable devices for health monitoring and environmental sensing. In this study, a self-powered wearable MoS2-based photodetector, integrated with a PDMS-MXene-based triboelectric nanogenerator (TENG) is presented. The TENG generates isometric AC voltage using a diode, and it is used to charge a capacitor for DC voltage output. The photodetector, with a responsivity of 1.25 × 105A/W, specific detectivity of 2×1013 Jones, millisecond response time, enhanced responsivity of 1.1×1010 V/W and specific detectivity of 9.5×1016 Jones while coupled with TENG, successfully measured heart rate using a 660 nm LED and compared well with a commercial pulse meter. Additionally, UV illumination was detected using a 395 nm LED in the AC mode of the TENG. The study’s results support the advancement of flexible, integrated, and sustainable wearable devices, offering solutions to challenges posed by current battery-powered devices.

Study on the Improvement of the Degradation Efficiency of Methylene Blue Using Pulsed Direct-Current Self-Power Supply.

Effective treatment of dye wastewater is currently a great concern and a research hotspot. Electrocatalysis has unique advantages in treating toxic and harmful refractory dye wastewater; however, it requires an external power supply, which increases energy consumption and cost. As a new energy collection technology, triboelectric nanogenerators (TENGs) have gained considerable attention. In this study, an origami multilayer spherical friction nanogenerator (Q-TENG) was developed for the removal of methylene blue (MB) from dye wastewater. The current and voltage output performances of Q-TENG were explored, and the removal and degradation mechanisms of MB were discussed. Results indicated that when the water wave acceleration a = 3 m/s2, the open-circuit voltage and short-circuit current reached the maximum values of 179 V and 9.4 μA, respectively. The self-powered catalytic degradation of MB using Q-TENG can produce more •OH and SO4-•, and the free radicals increase with increasing action time of Q-TENG, thus increasing the degradation efficiency of MB. This study provides a new strategy for solving the problem of high energy consumption during electrochemical reactions in wastewater treatment.

A 3D printed serrated contact structure triboelectric nanogenerator for swimming training safety monitoring

The wearable electronic devices integrated with 3D printing have attracted much attention, but the continuous power supply demand and limited application scenarios have limited their development. Here, we propose a 3D printed serrated contact structure triboelectric nanogenerator (S-TENG) designed for mechanical energy harvesting and swimming training safety monitoring. Leveraging the advancements in 3D printing technology, we created a flexible, lightweight sensor integrated with polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET) films on a serrated substrate. This configuration enhances the contact surface area, leading to a significant improvement in energy harvesting efficiency compared to flat structures. Specifically, the serrated structure resulted in a 64 %, 63 %, and 47 % increase in open-circuit voltage (Voc), short-circuit current (Isc), and transferred charge (Qsc), respectively, owing to the contact area and unique surface functional structure. The S-TENG device exhibits excellent performance under various bending angles, with Voc, Isc, and Qsc reaching up to 98.04 V, 4.35 μA, and 38.51 nC at 90° bending. Additionally, the S-TENG maintains stable output in different humidity environments due to its fully encapsulated design, ensuring reliable operation in aquatic settings. The S-TENG can accurately measure elbow swing amplitude and frequency, providing valuable real-time data for athletes and coaches. The S-TENG's ability to detect irregular movements and potential drowning incidents underscores its promise in enhancing swimmer safety. This research demonstrates the S-TENG's utility in both energy harvesting and motion monitoring, paving the way for advanced wearable sports sensors in various athletic disciplines.

Brain‐inspired Multimodal Synaptic Memory via Mechano‐photonic Plasticized Asymmetric Ferroelectric Heterostructure

AbstractNeuromorphic devices capable of emulating biological synaptic behaviors are crucial for implementing brain‐like information processing and computing. Emerging 2D ferroelectric neuromorphic devices provide an effective means of updating synaptic weight aside from conventional electrical/optical modulations. Here, by further synergizing with an energy‐efficient synaptic plasticity strategy, a multimodal mechano‐photonic synaptic memory device based on 2D asymmetric ferroelectric heterostructure is presented, which can be modulated by external mechanical behavior and light illumination. By integrating the asymmetric ferroelectric heterostructured field‐effect transistor and a triboelectric nanogenerator, the mechanical displacement‐derived triboelectric potential is ready for gating, programming, and plasticizing the synaptic device, resulting in superior electrical properties of high on/off ratios (> 107), large storage windows (equivalent to ≈95 V), excellent charge retention capability (> 104 s), good endurance (> 103 cycles), and primary synaptic behaviors. Besides, optical illumination can effectively synergize with mechanoplasticity to implement multimodal spatiotemporally correlated dynamic logic. The demonstrated multimodal memory synapse provides a facile and promising strategy for multifunctional sensory memory, interactive neuromorphic devices, and future brain‐like electronics embodying artificial intelligence.

Triboelectric-electromagnetic hybrid wind energy harvesting and multifunctional sensing device for self-powered smart agricultural monitoring

The power supply for numerous small electronic sensors, which are extensively used in agricultural settings, is a critical challenge for advancing the Agricultural Internet of Things (IoT) and fostering the development of smart agriculture in the upcoming era of intelligent technology. Hereby, a triboelectric-electromagnetic hybrid wind energy harvesting and sensing device (TEH-WSD) based on triboelectric-electromagnetic hybrid generator (TEHG) and multi-channel triboelectric nanogenerator (MC-TENG) for wind direction and speed sensing is proposed. Among them, the TEHG is used to collect wind energy. The instantaneous peak power of TENG units and EMG unit in TEHG can reach 5.95 mW and 5.65 mW respectively. In addition, the modified TEHG can measure the wind speed within the range of 3–5 m/s, and the output signal of MC-TEHG can be used to measure the wind direction based on the corresponding circuit and designed program continuously. Overall, TEH-WSD is capable of detection for the wind direction, wind speed, temperature and humidity information in the environment and this work provides a solution for wind energy collection and self-powered environmental monitoring in agricultural environment.

Stretchable and Elastic Triboelectric Nanogenerator with Liquid-Metal Grid-Patterned Single Electrode for Wearable Energy-Harvesting Devices.

Triboelectric nanogenerators (TENGs) have garnered significant attention as efficient energy-harvesting systems for sustainable energy sources in the field of self-powered wearable devices. Various conductive materials are used to build wearable devices, among which, gallium-based liquid metal (LM) is a preferred electrode owing to its fluidity and metallic conductivity even when strained. In this study, a stretchable, elastic, and wearable triboelectric nanogenerator is designed using a single electrode fabricated by embedding LM grid patterns into a stretchable silicone substrate through a two-step spray-coating process. Contrary to conventional double-electrode TENG that is challenging to integrate to human body, the LM grid-patterned single-electrode TENG (LMG-SETENG) has a simplified design and provides more flexibility. The LMG-SETENG can generate voltages of up to 100V via triboelectrification upon contact with the human body, even under various degrees of strain, owing to the fluidity of the LM electrode. The generated energy can be utilized as a sustainable energy source to power various small appliances. Moreover, the proposed LMG-SETENG can be utilized in soft robotics, electronic skin, and healthcare devices.

Flexible Organic Molecular Single Crystal-Based Triboelectric Device as a Self-Powered Tactile Sensor.

Triboelectric nanogenerators (TENGs) have proven to be effective at converting mechanical energy into electrical power, making them a viable technology for operating self-powered electronic devices used in medical diagnostics and environmental monitoring. In the present study, we demonstrate the utility of the flexible single crystals of an organic compound for the fabrication of a TENG as a self-powered tactile sensor. Triboelectrification was attained in single crystals as a result of surface functionalization with positively and negatively charged moieties, viz. Zn2+ and F-, respectively, which resulted in a variable surface potential and reversible adhesion through electrostatic interaction and induction phenomena. TENG incorporating the single crystals showed an output voltage of 2.4 V, a current density of ∼2.2 μA/m2, and a power density of ∼850 mW/m2 and was capable of charging commercial capacitors thereby ensuring its ability to be used as a self-powered touch sensor. Capitalizing on these features, a self-powered tactile sensor was fabricated to demonstrate limb movements. The excellent mechano-electric sensitivity (∼102 mV/kPa until 6 kPa range) and response time (∼38 ms) establish the viability of flexible organic single crystals for mechanical energy harvesting and biosensing applications that could pave the way for their utilization as biomedical wearable devices.

Ultralow-resistance and self-sterilization biodegradable nanofibrous membranes for efficient PM0.3 removal and machine learning-assisted health management

The development of multifunctional nanofibrous membranes (NFMs) that enable anti-viral protection during air purification and respiratory disease diagnosis for health management is of increasing importance. Herein, we unraveled a heterostructure-enhanced electro-induced stereocomplexation (HEIS) strategy to fabrication of poly(lactic acid) (PLA) NFMs enabling a combination of efficient PM removal, respiratory monitoring and self-sterilization. The strategy involved an electro-induced stereocomplexation (EIS) approach to trigger the generation of hydrogen bonds between enantiomeric poly(L-lactic acid) (PLLA) and poly(D-lactic acid) (PDLA) chains, promoting CO dipole alignment and molecular polarization during electrospinning. This was further enhanced by incorporation of Ag-doped TiO2 (Ag-TIO) nanodielectrics to promote the electroactivity and surface activity, conferring profound refinement of PLA nanofibers (from 460 nm to an ultralow level of 168 nm) and high porosities of over 91 %. Arising from the sustainable generation of plentiful charges based on triboelectric nanogenerator (TENG) mechanisms, the electroactive PLA NFMs exhibited remarkable triboelectric properties even in high-humidity environments (80 %RH), excellent PM0.3 filtration efficiency with an ultralow pressure drop (93.1 %, 31.8 Pa, 32 L/min), and 100 % antimicrobial efficiency against both E. coli and S. aureus. Moreover, a deep-learning algorithm based on convolutional neural network (CNN) was proposed to recognize various respiratory patterns. The proposed strategy confers the biodegradable NFMs an unusual combination of ultralow-resistance air purification and machine learning-assisted health management, signifying promising prospects in environmental protection and personal healthcare.

Performance of A Triboelectric Nanogenerator Utilising Coconut Husk Layer

Triboelectric nanogenerators, known as TENGs, offer great potential as versatile energy harvesting devices. In recent years, there has been a rise in TENG designs that prioritize compatibility with sustainable biomaterials, leading to new possibilities in green technology. The novelty of this work lies in its pioneering exploration of utilizing sustainable biomaterials, particularly coconut husk, within the field of Tribo-electric nanogenerators (TENGs). This study focuses on evaluating and characterizing coconut husk as TENG material considering factors such as rotational speed, vane count, and coarseness, all of which influence the output potential of the B-TENG. The B-TENG model employed in this research operates on a rotational sliding mode, featuring a biobased material layer of coconut husk, a layer of PTFE, and copper as electrodes. The B-TENG has a diameter of 100 mm with varying vane configurations (3-vane, 4-vane, and 5-vane). The sliding mode demonstrated impressive versatility, yielding output voltages spanning from 0.73 V to 4.0 V across rotational speeds of 200 RPM to 1400 RPM. Remarkably, the 5-vane fine-grained coconut husks achieved a maximum power of 121.10 mW at 10 Ohm and a power density of 3.84 mW/cm2. This research carries global significance, contributing to the advancement ofenergy harvesting technology. Its applications range from harnessing the motion of human bodies to rotating machineries in any industry.

Recent Advances in Wearable Textile-Based Triboelectric Nanogenerators.

We review recent results on textile triboelectric nanogenerators (T-TENGs), which function both as harvesters of mechanical energy and self-powered motion sensors. T-TENGs can be flexible, breathable, and lightweight. With a combination of traditional and novel manufacturing methods, including nanofibers, T-TENGs can deliver promising power output. We review the evolution of T-TENG device structures based on various textile material configurations and fabrication methods, along with demonstrations of self-powered systems. We also provide a detailed analysis of different textile materials and approaches used to enhance output. Additionally, we discuss integration capabilities with supercapacitors and potential applications across various fields such as health monitoring, human activity monitoring, human-machine interaction applications, etc. This review concludes by addressing the challenges and key research questions that remain for developing viable T-TENG technology.

A Study on the Mechanisms and Performance of a Polyvinyl Alcohol-Based Nanogenerator Based on the Triboelectric Effect.

Polyvinyl alcohol (PVA), a versatile polymer, is extensively used across many industries, such as chemicals, food, healthcare, textiles, and packaging. However, research on applying PVA to triboelectric nanogenerators (TENGs) remains limited. Consequently, we chose PVA as the primary material to explore its contact electrification mechanisms at the molecular level, alongside materials like Polyethylene (PE), Polyvinylidene fluoride (PVDF), and Polytetrafluoroethylene (PTFE). Our findings show that PVA has the highest band gap, with the smallest band gap occurring between the HOMO of PVA and the LUMO of PTFE. During molecular contact, electron transfer primarily occurs in the outermost layers of the molecules, influenced by the functional groups of the polymers. The presence of fluorine atoms enhances the electron transfer between PVA and PTFE to maximum levels. Experimental validation confirmed that PVA and PTFE contact yields the highest triboelectric performance: VOC of 128 V, ISC of 2.83 µA, QSC of 82 nC, and an output power of 384 µW. Moreover, P-TENG, made of PVA and PTFE, was successfully applied in self-powered smart devices and monitored human respiration and bodily movements effectively. These findings offer valuable insights into using PVA in triboelectric nanogenerator technologies.

Heat-Excitation-Based Triboelectric Charge Promotion Strategy.

The surface charge decay is observed at high temperatures due to thermionic emission, which, however, may not be the only mechanism contributing to the surface charge variation. Here, a triboelectric charge promotion strategy due to the heat-excitation effect of hot electrons near the fermi level is demonstrated, while the final charge is determined by the balance between thermionic emission and the heat-excitation effect. It is demonstrated that metals with lower work function exhibit a better heat excitation capability, and polymers with lower fluorine content in molecule chains further boost the charge output, where metal/Kapton pairs demonstrated a charge promotion of over 2 times at the temperature of 383K with good durability during 90min measurement. The heat-excitation effect and charge durability in sliding freestanding-triboelectric-layer (SFT) mode triboelectric nanogenerator (TENG) is demonstrated as well, where the energy is promoted by over 3 times and the capacitor charging speed is doubled as well, with an energy promotion from 109.34 to 373µJ per cycle to successfully trigger a discharger. This work suggests a promising future of the heat-excitation effect as a new charge promotion strategy for TENG toward different applications in high-temperature environments.

Self-powered wearable remote control system based on self-adhesive, self-healing, and tough hydrogels

The advent of the fifth-generation mobile communication network era induces a great potential for the design and development of self-powered wearable electronic devices. Hydrogels, as a typical material for flexible electrodes, have been widely employed in self-powered wearable electronic devices. However, the hydrogel-based triboelectric nanogenerator (H-TENG) is usually compromised by the challenges in data collection, operational stability, and manufacturability due to the unstable combination between the friction layer and the electrode layer, the occurrence of hydrogel damage during prolonged operation, and also the difficulty of machining sticky hydrogel electrodes. In the present study, a composite hydrogel composed of acrylamide, crotonyl alcohol, and 4-carboxyphenylboronic acid was synthesized via ultraviolet crosslinking, which was specially developed for H-TENG and wearable wireless remote control interface, featuring with excellent stretchability and mechanical strength as well as self-healing and self-adhesive properties. The open-circuit voltage of the H-TENG prepared with the hydrogel reached up to 165 V, and the output voltage remained almost unchanged following 10,000 cycles of compression test. Additionally, a wearable wireless remote control system was designed that could accurately control the multiple appliances and adjust different working modes using the H-TENG. Consequently, the development of the H-TENG and wearable wireless remote control system has the potential to provide a new methodology for the application of next-generation wearable devices in various areas, such as smart homes, as a representative example.

Use of Triboelectric Nanogenerators in Advanced Hybrid Renewable Energy Systems for High Efficiency in Sustainable Energy Production: A Review

Renewable energy is the best choice for clean and sustainable energy development. A single renewable energy system reveals an intermittent disadvantage during the energy production process due to the effects of weather, season, day/night, and working environment. A generally hybrid renewable energy system (HRES) is an energy production scheme that is built based on a combination of two or more single renewable energy sources (such as solar energy, wind power, hydropower, thermal energy, and ocean energy) to produce electrical energy for energy consumption, energy storage, or a power transmission line. HRESs feature the outstanding characteristics of enhancing energy conversion efficiency and reducing fluctuations during the energy production process. Triboelectric nanogenerator (TENG) technology transduces wasted mechanical energies into electrical energy. The TENG can harvest renewable energy sources (such as wind, water flow, and ocean energy) into electricity with a sustainable working ability that can be integrated into an HRES for high power efficiency in sustainable renewable energy production. This article reviews the recent techniques and methods using HRESs and triboelectric nanogenerators (TENGs) in advanced hybrid renewable energy systems for improvements in the efficiency of harvesting energy, sustainable energy production, and practical applications. The paper mentions the benefits, challenges, and specific solutions related to the development and utilization of HRESs. The results show that the TENG is a highly potential power source for harvesting energy, renewable energy integration, application, and sustainable energy development. The results are a useful reference source for developing HRES models for practical applications and robust development in the near future.

Triboelectric Nanogenerator Made with Stretchable, Antibacterial Hydrogel Electrodes for Biomechanical Sensing.

Triboelectric nanogenerators (TENGs) have attracted widespread attention as a promising candidate for energy harvesting due to their flexibility and high power density. To meet diverse application scenarios, a highly stretchable (349%), conductive (1.87 S m-1), and antibacterial electrode composed of carbon quantum dots/LiCl/agar-polyacrylamide (CQDs/LiCl/agar-PAAm) dual-network (DN) hydrogel is developed for wearable TENGs. Notably, the concentration of agar alters the pore spacing and pore size of the DN hydrogel, thereby impacting the network cross-linking density and the migration of conductive ions (Li+ and Cl-). This variation further affects the mechanical strength and conductivity of the hydrogel electrode, thus modulating the mechanical stability and electrical output performance of the TENGs. With the optimal agar content, the tensile strength and conductivity of the hydrogel electrode increase by 211 and 719%, respectively. This enhancement ensures the stable output of TENGs during continuous operation (6000 cycles), with open-circuit voltage, short-circuit current, and transferred charge increasing by 200, 530, and 155%, respectively. Additionally, doping with CQDs enables the hydrogel electrode to effectively inhibit the Gram-negative bacterium Escherichia coli. Finally, the TENGs are utilized as a self-power smart ring for efficient and concise information transmission via Morse code. Consequently, this study introduces a creative approach for designing and implementing multifunctional, flexible wearable devices.

Preparation and Characterization of Amide-Containing Polyimide Films with Enhanced Tribopositivity for Triboelectric Nanogenerators to Harvest Energy at Elevated Temperatures

Preparation and Characterization of Amide-Containing Polyimide Films with Enhanced Tribopositivity for Triboelectric Nanogenerators to Harvest Energy at Elevated Temperatures

Triboelectric and iontronic dual-responsive bioinspired ionic skin for human–like dexterous robotic manipulation

Powerful tactile perception is keystone for robots to achieve human-like dexterous manipulation. However, endowing robots with tactile perception capabilities that approach or even surpass those of humans is a challenge. Organisms can perceive complex environments rapidly, and almost all perception is related to the directional transport of ions. Inspired by this mechanism, we design a flexible dual-responsive skin (FDRS) based on ions migration for proximity and tactile somatosensation, which is consisting of single-electrode triboelectric nanogenerator and iontronic sensor, achieving surpassing-skin capabilities. The single-electrode triboelectric nanogenerator can encode the proximity information of approaching targets into a series of voltage pulses with fast response time (100 μs). The iontronic tactile unit based on the hierarchical micro-hemispherical gel layer achieves high linearity (R2 = 0.998) over a broad range of 0–700 kPa. We demonstrate the applications of FDRS for three-dimensional object recognition and robotic control. These capabilities of the multilayer integrated FDRS provide new perspectives for the future development of human-like dexterous robotic manipulation.

Sodium alginate supramolecular nanofibers in synergy with surface crack engineering to prepare tough and highly sensitive hydrogels

Soft and wet hydrogels often struggle to achieve both toughness and high sensitivity simultaneously, limiting their usefulness in flexible devices. To tackle this challenge, we devised a strategy that combines supramolecular sodium alginate nanofibers, utilizing Zr4+ as physical crosslinkers, with surface crack engineering via the micro-phase separation of polyaniline, to create a physically and chemically dual crosslinked polyacrylamide (PAM)/sodium alginate (SA)/polyaniline (PANI) hydrogel with exceptional toughness and high sensitivity. Owing to the supramolecular sodium alginate nanofibers, the dual crosslinked hydrogel exhibited a tensile strength of 0.391 MPa, an elongation at break of 568.9 %, and a toughness of 1.020 MJ/m3. The in-situ polymerized polyaniline layer, confined within the dense network, introduced micro-cracks onto the hydrogel surface, resulting in a high gauge factor of 11.4 for the fabricated hydrogel. Furthermore, integrating this hydrogel into a triboelectric nanogenerator transformed it into self-powered sensors capable of detecting external forces and generating various signals without power supply. These findings suggest that the developed hydrogel held great potential in diverse fields, including human motion detection, human-machine interaction, and wearable electronic devices.

Droplet-based triboelectric devices using liquid dielectrics for self-powered sensing applications

Triboelectric nanogenerators (TENGs) have attracted great interests by exploiting the complex interplay between contact electrification and electrostatic induction. The versatility of tribo-dielectric materials offers significant advantages for environmentally adaptive device design. In this regard, liquid dielectrics provide intimate contact between filled materials and high dielectric strength. Herein, a liquid dielectric-based TENGs system featuring a charge-transfer liquid layer is presented. A multifaceted summary is presented to illustrate the relationship between liquid dielectric materials and charge transfer mechanisms. New strategies for exploiting the dielectric properties of various liquids to control their electrical properties and monitor the parameters of liquid dielectric properties are highlighted. Additionally, it contributes to the advancement of self-powered sensing technology with increased flexibility, capacitance tuning, and sensor functionality through easy modularization. These achievements contribute to the understanding of charge transfer mechanisms in liquids and highlight their potential for self-powered sensing applications.

Functional Tactile Sensor Based on Arrayed Triboelectric Nanogenerators

AbstractIn the era of Internet of Things (IoT) and Artificial Intelligence (AI), sensors have become an integral part of intelligent systems. Although the traditional sensing technology is very mature in long‐term development, there are remaining defects and limitations that make it difficult to meet the growing demands of current applications, such as high‐sensitivity detection and self‐supplied sensing. As a new type of sensor, array triboelectric nanogenerators (TENG)‐based tactile sensors can respond to wide dynamic range of mechanical stimuli in the surrounding environment and converting them into quantifiable electrical signals, thus realizing real‐time self‐supplied tactile sensing. The array structure allows for fine delineation of the sensing area and improved spatial resolution, resulting in accurate localization and quantification of the detected tactile signals, and have been widely used in wearable devices, smart interaction, medical and health detection, and other fields. In this paper, the latest research progress of functional tactile sensors based on arrayed triboelectric nanogenerators is systematically reviewed from the aspects of working mechanism, material selection, material processing, structural design, functional integration, and application. Finally, the challenges faced by arrayed triboelectric tactile sensors are summarized with a view to providing inspiration and guidance for the future development of tactile sensors.