Transparent Triboelectric Nanogenerator Research Articles

Phosphor‐Loaded Triboelectric Film‐Based Multipurpose Triboelectric Nanogenerators for Highly‐Efficient Energy Harvesting, Sensing, and Self‐Illumination Applications

AbstractA novel approach is proposed for combining phosphor materials with triboelectric nanogenerators (TENGs) for mechanical energy harvesting and illumination applications. For this purpose, strongly reddish‐orange‐emitting Ba0.5Sr0.5Nb2O6:0.25 mol Eu3+ (BSNb:0.25Eu) phosphor materials are synthesized. The photoluminescence properties of the synthesized BSNb:0.25Eu are analyzed. The synthesized BSNb:0.25Eu is utilized as a dielectric filler inside a polydimethylsiloxane polymeric film due to its high dielectric properties to improve the overall dielectric properties of the composite film (CF). TENG devices are fabricated using phosphor‐loaded CFs as the tribonegative layer, transparent polyvinyl alcohol as the tribopositive layer, and aluminum as the conductive electrode. All the TENGs operate in a contact‐separation mode, and the highest electrical output is attained by optimizing the phosphor filler concentration in the CF. The optimized TENG exhibits excellent stability in long‐term operational tests, under varying harsh ambient temperatures. Indium tin oxide sputtered on both triboelectric films as an electrode and combined with a transparent hard substrate to obtain a fully transparent TENG. A self‐illuminating TENG (SI‐TENG) is fabricated by integrating near‐ultraviolet light‐emitting diodes between two identical TENGs. The SI‐TENG can harvest the mechanical energy available in the surrounding environment and illuminate it as a light source. Additionally, the proposed phosphor‐loaded polymer films can be employed for optical thermometry and mechanical energy harvesting via SI‐TENG on a large scale.

Highly flexible and transparent triboelectric nanogenerators toward reliable energy harvesting and recognition

Triboelectric nanogenerators (TENG) have been a research hotspot with the rapid development of medical rehabilitation, environmental monitoring and human-computer interaction. However, most of the existing studies are based on the electric-collecting properties of TENG device, and few studies have considered the light transmittance of TENG device. Here, we propose a strategy for this dilemma. That is the transparent TENG device, which displays a remarkable charge generation ability, transparent and reliable performance. The measured voltage values show a steady change trend regardless of different days, bending times or bending angles, suggesting the excellent stability of the transparent TENG device. More importantly, the transparency property of TENG solves the light transmission problem of the TENG device integrated materials, which supplies a satisfactory solution to expand application scenarios for current TENG device. An idea based on the recognition of human hands in transparent scenarios is proposed. The hand recognition rate of the transparent TENG is as high as 100% in the accuracy test of six volunteers. In addition, we carried out the real-time identification of four individuals based on the data processing and display module of the transparent TENG device and the recognition rates were 100%, 100%, 81% and 26%. This study proposes a new method to design single electrode TENG device showing its effectiveness in light transmission applications and superior electrical properties.

Light and triboelectrification management by nanostructure coupled with plasma-polymerized-fluorocarbon thin film for enhancing performance of energy harvestings

Nanostructures are pivotal in enlarging surface area, increasing transparency, and enhancing power generation. We presented a novel methodology that employs plasma from a linear ion beam source to fabricate irregular nanostructures on a colorless polyimide (CPI) surface. This innovative technique improves transparency, positioning it as an attractive choice for energy and optoelectronic applications. Furthermore, we enhanced the nanostructured CPI surface by applying a plasma-polymerized-fluorocarbon (PPFC). This coating, notable for its low refractive index and superior triboelectrification properties, enabled us to attain ultra-low reflectance (<1%) and a high surface charge density. Integrating PPFC with nanostructured CPI, we amplified the effective surface area of a triboelectric nanogenerator (TENG) by 14.8%, leading to a boost in TENG performance with outputs reaching 184.0 V and 72.8 μA. We also introduced a figure of merit (FOM) for transparent TENGs. The FOM for PPFC/nanostructured CPI exhibits an impressive value of 206.5. In flexible perovskite solar cells (f-PSCs) incorporating PPFC/nanostructured CPI, we observed an increase in short-circuit current density from 22.61 to 23.24 mA/cm2 and an enhancement in power conversion efficiency from 17.47% to 18.25%. Our results validate the efficacy of this approach in both transparent TENGs and f-PSCs, marking a substantial advancement in their performance.

Biodegradable, transparent, and antibacterial alginate-based triboelectric nanogenerator for energy harvesting and tactile sensing

The utilization of natural biomaterials in the construction of triboelectric nanogenerators (TENG) has significant implications for the advancement of sustainable self-powered devices. Sodium alginate (SA), an eco-friendly and biodegradable triboelectric material with excellent transparency, is considered an ideal material for wearable TENGs. In this work, we report a biodegradable, transparent, and antibacterial SA-based TENG for mechanical energy harvesting and self-powered tactile sensing. The addition of glycerol, an environment-friendly additive, can enhance flexibility and adhesiveness of the SA, which resulted in well-transferred AgNWs/SA electrodes with high transparency and conductivity. The major parameters that affect the output performance of the fabricated TENG are investigated, including the frequency, thickness and area of the triboelectric layers. The output voltage, transferred charge, and peak power of the TENG could reach up to 53 V, 18 nC, and 4 μW, respectively, which is sufficient to power small electronic devices. In addition, the fabricated TENG device also shows excellent antibacterial and biodegradable capabilities. Finally, the TENG is demonstrated to be an effective self-powered tactile sensor for pressure mapping, human movement monitoring, and wearable human–machine interfacing. This work provides a new strategy to design flexible transparent TENGs with biodegradable SA and paves the way for developing next-generation self-powered transient electronics.

All-aerosol-sprayed high-performance transparent triboelectric nanogenerator with embedded charge-storage layer for self-powered invisible security IoT system and raindrop-solar hybrid energy harvester

Practical utilization of the triboelectric nanogenerators (TENGs), which have unique advantageous aspects of a simple operation mechanism, material selection diversity, and high energy conversion efficiency, requires high functionality as well as a scalable fabrication to broaden the applicable fields. Here, we report the concept of all-aerosol-sprayed transparent TENG (ST-TENG) by sequentially spraying total three layers of a silver nanowire conductive layer, transparent polystyrene charge-storage layer, and fluoropolymer contact layer. All layers were achieved by aerosol spray process, thereby exhibiting high design flexibility enough to fabricate ST-TENGs on various pre-made commercial devices. The presence of the transparent polystyrene layer as a charge storing interlayer significantly enhances the power density of the ST-TENG up to 818 mW/m2. As proof-of-concept applications, a self-powered invisible security internet-of-things system, which could blend with the surroundings, exploited biomechanical energy from foot-step for energy harvesting and invasion sensing. Furthermore, by exploiting the all-aerosol-spray process and high light transmittance of the ST-TENG, a hybrid energy harvester to simultaneously generate electricity from solar and rain energy was directly fabricated on a commercial solar panel. This work provides the brand-new concept of TENG with a scalable in-situ fabrication process, enhanced performance, and outstanding light transmittance.

Transparent and flexible touch on/off switch based on BaTiO3/silicone polymer triboelectric nanogenerator

Tactile sensors and wearable electronics based on triboelectric nanogenerators (TENGs), which convert environmental mechanical energy to the electrical energy, have extensive applications. Features such as flexibility, low weight, biocompatibility and transparency make energy generators, more eminent and practical. In this study, an elastic and non-opaque silicone-based polymer has been utilized as a charge generating layer of the TENGs. In order to improve the triboelectric properties as well as enhancement of the induced electrical charge, it was composited with various materials including TiO2, BaTiO3, Al2O3, ZnO, CaCO3 and graphene oxide. The flexible TENG’s maximum output power density of 10.10 W/m2, voltage of 660 V and current of 72 μA was obtained from the Si polymer/BaTiO3 composite layer with the fracture stain of 260% on the aluminum contact (94% and 92% enhancement compared to the pure Si polymer, in voltage and current respectively). For the purpose of making a transparent, elastic and ultra-lightweight TENG, composite layer were deposited on a conductive electrode based on silver nanowires (AgNWs). The built-in nanogenerator had the transparency of 79%, output power density of 27 kW/m3 and weight of 8 mg/cm2. It has been employed as a transparent, elastic, flexible and ultra-lightweight touch on/off switch which is applicable in harsh environmental conditions and utilized as a flexible wristband to switch on/off the LED, thermometer and oximeter device. The introduced large-scale flexible and transparent TENG has a great potential to be applied in smart home applications and wearable electronics.

Semitransparent polymer solar cell/triboelectric nanogenerator hybrid systems: Synergistic solar and raindrop energy conversion for window-integrated applications

Development of photovoltaic (PV)-derived hybrid power systems can overcome the weather-dependent electricity production and increase the amount of dispatchable renewable energy generation. Herein, monolithic hybrid devices are developed via rational integration of high-performance semitransparent polymer solar cells (ST-PSCs) and liquid−solid triboelectric nanogenerators (TENGs). High-performance PSCs with efficiencies of 17.4% for rigid and 15.7% for flexible devices are achieved. Further electrode modifications and integration of transparent TENGs synergistically balance the above-bandgap photon harvesting and transparency in a broad wavelength range (380 − 1000 nm), yet significantly reduce the transmittance in the near-infrared wavelength range (1000 − 2500 nm) of hybrid devices. The hybrid devices simultaneously provide high visible light transparency, good color fidelity, efficient heat resistance and possibility to integrate on rigid and flexible substrates. The hybrid devices attain a high solar conversion efficiency of 10.1% under 1 sun, indicating efficient light-to-electricity conversion (a maximum electrical power output: 101 W m−2) on sunny days. The hybrid devices can also generate a maximum electrical power output of 2.62 W m−2 through waterdrop energy conversion, implying complementary green electricity production on rainy days. The controlled ambient temperature and specific transmittance windows provided by the hybrid devices sustain plant growth and highlight their great potential in agricultural applications. Gratifyingly, this work demonstrates the first example of ST-PSC/TENG hybrid systems for scaling up renewable power generation in different weather conditions, considering architectural and agricultural applications.

Fabrication of a Low Cost Triboelectric Nanogenerator (TENG) for Wearable Devices

During the last few years, considerable research has been conducted for the design and development of the self-powered devices to supply sustained power to various electronic devices by converting waste mechanical energy into useful electrical energy. Out of many energy sources available in nature, mechanical energy has attracted the researchers due to its availability in abundance. Various methods such as an electromagnetic [1], electrostatic [2] and piezoelectric [3] are being used for converting this waste mechanical energy into useful electrical energy. A novel, eco-friendly and highly reliable triboelectric nanogenerator (TENG) with low cost of fabrication has been considered for fabrication of proposed device [4]. Contact electrification process has been used at the interface of two different materials (metal and a polymer) to generate the electrical energy in the proposed TENG. In order to enhance the surface charge density of the contact electrification process, it is required that the surface area of contact should be increased by surface engineering using micro and nanostructures [5]. Many studies have shown the polymer surface engineering by various processes like template based moldings and plasma treatment [6], surface engineering on the metals like gold nanoparticles (AuNP’s) of different shapes and sizes on the other hand have shown various applications where gold have been used such as in sensors as it is highly robust against the oxygen present in the air and thus it may not get corroded or oxidized unlike other metals. With the deposition of gold nanoparticles on the surface of the metal, an improvement in the output parameters will be observed as compared with the metal without any surface engineering. Another advantage of using gold nanoparticles is that no special protection packaging is required in order to protect the TENG device because of the gold’s robustness against oxygen. The surface stability of gold nanoparticles makes them suitable in various TENG applications.In this paper, we present a very simple technique to fabricate a triboelectric nanogenerator consisting of aluminum and PDMS (Polydimethylsiloxane) layers to harvest mechanical energy present in our surroundings. The proposed TENG device is capable of generating electricity by the process of contact-separation based triboelectrification between the anodic layer of aluminum (metal) and a cathodic layer of PDMS (polymer). To improve the performance of fabricated TENG, spherical shaped gold nanoparticles were synthesized and sprayed on the metallic layer to increase its contact area by increasing the surface roughness. In order to characterize the samples, various characterization techniques has been used like FESEM (Field Emission Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy). With the application of static weights/ force by hand on the fabricated TENG device, an open circuit voltage of 169 mV, short circuit current of 120.4 µA and maximum output power of 6.006µW has been achieved for an applied load resistance of 68 kΩ. Further the voltage, current and power output performance of the fabricated device has been measured and studied for different load resistances. The fabricated TENG demonstrates its application in the self-powered systems and wearable devices. The deposition of gold nanoparticles (AuNP’s) on the surface of the aluminum metal results in increasing the surface charge density with an increase in the surface area of contact between the metal and the PDMS based polymer layer. The device is sandwiched and force is applied either by fingers or by the use of static weights. With the variations in the force applied, there is a variation in various parameters like open circuit voltage, short circuit current and power. From the results it has been observed that the AuNP’s based TENG generates good results in spite of the fact that the gold has inferior triboelectric coefficient as compared with other metals. The AuNP’s based TENG so fabricated shows high robustness even in very hot and humid environment. References Bin, et al. Electromagnetic Energy Harvesting from Vibrations of Multiple Frequencies. J. Micromechanics Microengineering 19, 035001 (2009).Suzuki, , Miki, D., Edamoto, M. &Honzumi, M.A MEMS Electrets Generator with Electrostatic Levitation for Vibration-Driven Energy-Harvesting Applications. J. Micromechanics Micro engineering 20, 104002 (2010).Seol, M. L. et al. Design Strategy for a Piezoelectric Nanogenerator with a Well Ordered Nano shell ACS Nano 7, 10773–10779 (2013).Li, , Sun, J. & Chen, M. Triboelectric Nanogenerator Using Nano AgInk as Electrode Material. Nano Energy 3, 95–101 (2014).Fan, -R. et al. Transparent Triboelectric Nanogenerators and Self-Powered Pressure Sensors Based on Micro patterned Plastic Films. Nano Lett. 12, 3109–3114(2012).Bai, et al .Integrated Multilayered Triboelectric Nanogenerator for Harvesting Biomechanical Energy from Human Motions. ACS Nano 7, 3713–3719 (2013). Figure 1

Ultrahigh sensitive, eco-friendly, transparent triboelectric nanogenerator for monitoring human motion and vehicle movement

Natural biomaterials based triboelectric nanogenerator (TENG) is crucial for sustainable self-powered devices that achieves high outputs, biocompatibility, and reduces the environment impact. Meanwhile, transparent TENG can integrate with commercial optoelectronic devices to simultaneously realize the self-powering sensing and visual transmission of information. Herein, we prepared an eco-friendly, flexible, transparent chitosan@starch composite film by drop casting process, which reveals high transmittance exceed 88% in the visible light range. A transparent TENG was designed by pairing the chitosan@starch composite film with the fluorinated ethylene propylene (FEP) film, and transparent PET/ITO electrodes. The optimized chitosan@starch-FEP based TENG (CS-F/TENG) exhibits the open-circuit voltage of ∼1080 V, short-circuit current of ∼16.9 mA m−2 and the maximum power density of ∼5.07 W m−2. Ultrahigh sensitivity of 46.03 V kPa−1 in the pressure range of 1.25–6.25 kPa is achieved by the CS-F/TENG as a self-powered force sensor, and its potential applications in monitoring human motion and vehicles’ speed are also demonstrated. Our work provides novel insights in the utilization of sustainable chitosan@starch composite film for transparent wearable TENG with decent output performance, and also facilitates the potential applications of this device in monitoring human motion and vehicle movement.

Skin-integrated, stretchable, transparent triboelectric nanogenerators based on ion-conducting hydrogel for energy harvesting and tactile sensing

The high demand of flexible and biocompatible power supplies drives the research of soft and wearable triboelectric nanogenerators (TENGs), as which have been proven to be an outstanding candidate for energy harvesting. However, the reported wearable TENGs commonly face the hurdles of limited stretchability, poor transparency, low power outputs, and complicated fabrication processes. Herein, we report a single-electrode mode based transparent triboelectric nanogenerator (T-TENG), with remarkable electrical performance and good stretchability. A self-developed hydrogel (mainly composed of the interpenetrating polymer network and mobile ions) is applied as the conductive layer for the T-TENG, as which owns high stretchability (~ 850%), great electrical conductivity (1.2 S/m) and transparency of 90%. The great electrical performance of the TENG could be proven by the open-circuit voltage of ~684 V and short-circuit current of ~116 µA under a gentle tapping force of ~16.67 kPa. The great outputs enable the T-TENG lighting up 360 light-emitting diodes (LEDs) at the same time. Moreover, the operational performance of the T-TENG is very robust where the outputs are almost unaffected after hundreds of cycles of stretching, folding, twisting, and smashing. To demonstrate its mechanical sensing capability, the T-TENG is attached to a finger to be bent, twisted, and folded, where there are clear electrical signals along with the deformations. With its high sensitivity, an 8 × 8 soft sensing array with low crosstalk is developed, and it could respond towards the gentle poking by finger in an accurate approach. The T-TENG reported in this work demonstrates promising applications in the development of self-powered flexible electronics.

Lithium Bonds Enable Small Biomass Molecule-Based Ionoelastomers with Multiple Functions for Soft Intelligent Electronics.

Lipoic acid (LA), which originates from animals and plants, is a small biomass molecule and has recently shown great application value in soft conductors. However, the severe depolymerization of LA places a significant limitation on its utilization. A strategy of using Li-bonds as both depolymerization quenchers and dynamic mediators to melt transform LA into high-performance ionoelastomers (IEs) is proposed. They feature dry networks while simultaneously combining transparency, stretchability, conductivity, self-healing ability, non-corrosive property, re-mouldability, strain-sensitivity, recyclability, and degradability. Most of the existing soft conductors' drawbacks, such as the tedious synthesis, non-renewable polymer networks, limited functions, and single-use only, are successfully solved. In addition, the multi-functions allow IEs to be used as soft sensors in human-computer interactive games and wireless remote sports assistants. Notably, the recycled IE also provides an efficient conductive filler for transparent ionic papers, which can be used to design soft transparent triboelectric nanogenerators for energy harvesting and multidirectional motion sensing. This work creates a new direction for future research involving intelligent soft electronics.

Stretchable Unsymmetrical Piezoelectric BaTiO3 Composite Hydrogel for Triboelectric Nanogenerators and Multimodal Sensors.

Improving output performance of triboelectric nanogenerators (TENGs) is crucial for expanding their applications in smart devices, especially for flexible and wearable bioelectronics. In this study, we design and fabricate a flexible, stretchable, and highly transparent TENG based on an unsymmetrical PAM/BTO composite film, made of polyacrylamide (PAM) hydrogel and BaTiO3 nanocubes (BTO NCs, BTO), and the TENG performance can be tailored by adjusting the amount and distribution location of BTO. The stretchable hydrogel electrode could bear over 8 times stretching. By changing the content and distribution location of BTO in the unsymmetrical hydrogel film, the output of the fabricated TENGs could be improved, acting as pressure sensors with high sensitivity to distinguish a spectrum of forces (0.25-6 N) at the low frequency. The mechanism of the enhanced output performance of the PAM/BTO composite hydrogel-based TENG is discussed in detail. By integrating piezoresistive, piezoelectric, and triboelectric effects, the optimized TENG and piezoresistive sensors are used as multimodal biomechanical sensors for detecting the motions of human bodies, pressure, and curvature with high sensitivity.

All-Aerosol-Sprayed High-Performance Transparent Triboelectric Nanogenerator with Embedded Charge-Storage Layer for Self-Powered Invisible Security Iot System and Raindrop-Solar Hybrid Energy Harvester

All-Aerosol-Sprayed High-Performance Transparent Triboelectric Nanogenerator with Embedded Charge-Storage Layer for Self-Powered Invisible Security Iot System and Raindrop-Solar Hybrid Energy Harvester

Flexible Hybrid Nanogenerator for Self‐Powered Weather and Healthcare Monitoring Sensor

AbstractNowadays, people can receive several types of information from portable and wearable devices. However, the limited working time period, rigid characteristic, and bulky size of the conventional power sources need to be improved for rocketing the compatibility with portable and wearable devices. In this paper, a flexible hybrid nanogenerator (FHNG) is presented by combining a solar cell, a transparent triboelectric nanogenerator (TENG), and a piezoelectric nanogenerator (PENG). The FHNG can sustainably collect energy from various energy sources. The FHNG can act as a self‐powered weather monitoring device by harvesting and detecting raindrops, wind, and sunlight. Especially, the FHNG can simultaneously harvest both electro‐static energy and impact energy of raindrops by the TENG and PENG parts, respectively. Owing to the hydrophobic surface of the outermost TENG part, the FHNG obtains a self‐cleaning characteristic which can improve the output performance of the FHNG under sunlight and raindrops. Furthermore, the FHNG can be used as a wearable self‐powered healthcare monitoring device by sensing the health information, such as human motion, arterial pulse rate, or respiration rate based on the electrical output when attached to a human body. This research contributes to broadening the coverage of self‐powered nano‐device in portable and wearable electronics.

Soft and transparent triboelectric nanogenerator based E-skin for wearable energy harvesting and pressure sensing

The demand for wearable sensor technologies has increased with the recent increase interactions humans–electronic device interactions. However, the supplying power for wearable sensors, such as E-skin and flexible electronics, remains a major technical challenge. Herein, we report a triboelectric nanogenerator (TENG)-based E-skin capable of biomechanical energy harvesting and self-pressure sensing without an external power source. PTFE-molded micro-patterned PDMS and a conductive yarn were combined to implement an E-skin with flexibility, elasticity, high sensitivity, and excellent stability. The manufactured E-skin generates a power of 154 mW m−2 for an external force of 1 kgf and exhibits stable characteristics without deterioration of output even under 4500 cycles of repeated pressure. The E-skin can charge a capacitor and drive an electronic watch as well as monitor physiological signals, such as arterial pulses. The method used in this study can be extended to potential applications for power supply in wearable/soft electronics, medical monitoring, and human–machine interfaces.

Synthesis of fluorinated polyimide towards a transparent triboelectric nanogenerator applied on screen surface

A fluorinated polyimide film is synthesized toward the transparent triboelectric nanogenerator applied on touch screen surface to convert the mechanical energy into electrical energy.

Triboelectric and Piezoelectric Nanogenerators for Future Soft Robots and Machines.

SummaryThe triboelectric nanogenerator (TENG) and piezoelectric nanogenerator (PENG) are two recently developed technologies for effective harvesting of ambient mechanical energy for the creation of self-powered systems. The advantages of TENGs and PENGs which include large open-circuit output voltage, low cost, ease of fabrication, and high conversion efficiency enable their application as new flexible sensors, wearable devices, soft robotics, and machines. This perspective provides an overview of the current state of the art in triboelectric and piezoelectric devices that are used as self-powered sensors and energy harvesters for soft robots and machines; hybrid approaches that combine the advantages of both mechanisms are also discussed. To improve system performance and efficiency, the potential of providing self-powered soft systems with a degree of multifunctionality is investigated. This includes optical sensing, transparency, self-healing, water resistance, photo-luminescence, or an ability to operate in hostile environments such as low temperature, high humidity, or high strain/stretch. Finally, areas for future research directions are identified.

Hybrid energy system based on solar cell and self-healing/self-cleaning triboelectric nanogenerator

Solar cells acted as sustainable energy harvest are quickly spread across the worldwide. However, the output performance of solar cells is dramatically reduced in rainy day and the potential mechanical damages to the surface solar cell may also suppress its output capability. Herein, we propose a hybrid energy system consisted of a solar cell and a self-healing/self-cleaning triboelectric nanogenerator (TENG) for harvesting both solar and raindrop energies. The application of self-healable TENG for hybrid energy system has been a challenging task, since it is difficult to maintain both the super-hydrophobicity and healable capability for the electrification surface of TENG. This self-healable and transparent TENG shows an excellent output performance under rainy day with a peak short-circuit current of 0.8 μA and a peak open-circuit voltage of 6 V, respectively, while it can work very well with solar cell under sunny days. The self-healing TENG with elastic texture can serve as a protection layer for the solar cell, where the broken risk of the solar cell can be significantly suppressed. This proposed hybrid energy system can be used as a compensation for the currently widely used solar cells and provide a promising strategy to harvest energy from multiple sources.

Highly stretchable and transparent triboelectric nanogenerator based on multilayer structured stable electrode for self-powered wearable sensor

In recent years, triboelectric nanogenerators (TENGs) have grasped considerable attentions as sustainable power sources for next-generation electronics. However, far too rare research has been carried out to simultaneously achieve stretchability and transparency in TENGs. Here, we developed a stretchable and transparent TENG based on a Mxene-AgNWs-Mxene-polyurethane nanofibers (MAMP) electrode which exhibits excellent optoelectronic properties with low sheet resistance of 10.1 Ω/sq at the transmittance of 87.6%. Meanwhile, the as-prepared electrode achieves outstanding stretchability and durability with maximum strain of 180%, as well as 42% resistance variation after 1000 stretch-release cycles at 65% strain, which is attributed to the synergistic effect of the reinforcement of nanofiber-based scaffold and the improvement of adhesion between conductive network and elastic matrix by Mxene. Furthermore, the stretchable and transparent MAMP-TENG is employed as energy harvester and motion sensor, producing output voltage of 38 V and current density of 1.67 mA/m 2 just by hand tapping. The integration of sustainable power source and motion sensor with the attributes of stretchable and transparent in one makes it promising for applications in wearable devices and human-machine systems. • The electrospun polyurethane nanofibers as a scaffold can reinforce AgNWs network. • Mxene effectively enhances the adhesion between AgNWs network and PU nanofibers. • The electrode has excellent optoelectronic property, stretchability and durability. • Highly stretchable and transparent TENG as energy harvester and motion sensor.

Stretchable, transparent triboelectric nanogenerator as a highly sensitive self-powered sensor for driver fatigue and distraction monitoring

Abstract The ever-increasing automobiles have caused large number of traffic accidents every year. Fatigue driving and distracted driving are two main reasons for most of traffic accidents. Thus, intelligent transportation has attracted much attention. In this work, a stretchable polyacrylamide (PAAM) -LiCl-based triboelectric nanogenerator (PL-TENG) is utilized for the first time to monitor driver fatigue and distraction by attaching them to the face and neck of a driver. These PL-TENG sensors can detect eye closure, mouth closure, and neck rotation with high accuracy. Eye blink duration (BD), blink interval duration (BID), percentage of eyelid closure over time (PERCLOS) and yawn frequency (YF) are chosen as indicators of driver fatigue, while mouth closure and head positioning are chosen as indicators of driver distraction. The PL-TENG sensor has the characteristics of high voltage, high sensitivity and good biocompatibility, which demonstrates that the PL-TENG sensors are more sensitive than traditional fatigue detection systems. This work paves a new way for designing highly sensitive self-powered sensor in an intelligent transportation system.