Flexible Wood-Based Triboelectric Self-Powered Smart Home System.

With the rapid development of the Internet of Things, artificial intelligence, and big data, the smart home has played a critical role in human life and smart cities, where large amounts of distributed sensors should be applied. Here, we report a natural wood-based triboelectric self-powered sensor (WTSS) for building the smart home system. Based on an effective and simple treatment strategy for natural wood, the WTSS shows superior sensitivity, flexibility, stability, and thinness.

Highly Stable and Eco-friendly Marine Self-Charging Power Systems Composed of Conductive Polymer Supercapacitors with Seawater as an Electrolyte.

A self-charging power system harvesting random and low-frequency wave energy into electricity provides a promising strategy for the construction of smart oceans. However, the system faces huge challenges of easy corrosion in the marine environment and the utilization of toxic organic electrolytes in energy storage devices. To address the issues above, a seawater supercapacitor (SWSC) for the marine self-charging power system is rationally proposed by using a conductive polymer, polypyrrole with hollow morphology (h-PPy), to enhance the stability and capacitance while using seawater as an eco-friendly electrolyte to reduce the cost and achieve sustainability.

Highly sensitive strain sensors based on piezotronic tunneling junction.

Piezotronics with capacity of constructing adaptive and seamless interactions between electronics/machines and human/ambient are of value in Internet of Things, artificial intelligence and biomedical engineering. Here, we report a kind of highly sensitive strain sensor based on piezotronic tunneling junction (Ag/HfO/n-ZnO), which utilizes the strain-induced piezoelectric potential to control the tunneling barrier height and width in parallel, and hence to synergistically modulate the electrical transport process. The piezotronic tunneling strain sensor has a high on/off ratio of 478.

Nondestructive Dimension Sorting by Soft Robotic Grippers Integrated with Triboelectric Sensor.

In smart logistics, traditional manual sorting and sorting systems based on rigid manipulators limit the warehousing development and damage the goods. Here, a nondestructive sorting method based on bionic soft fingers is proposed. This method is implemented by the soft robotic gripper (SRG) for grasping of the breakable objects, the triboelectric sensor (TES) for size sorting of the objects, and the signal processing module.

Ultrathin Eardrum-Inspired Self-Powered Acoustic Sensor for Vocal Synchronization Recognition with the Assistance of Machine Learning.

With the rapid development of human-machine interfaces, artificial acoustic sensors play an important role in the hearing impaired. Here, an ultrathin eardrum-like triboelectric acoustic sensor (ETAS) is presented consisting of silver-coated nanofibers, whose thickness is only 40 µm. The sensitivity and frequency response range of the ETAS are closely related to the geometric parameters.

Fish-Wearable Data Snooping Platform for Underwater Energy Harvesting and Fish Behavior Monitoring.

Conventional approaches to studying fish kinematics pose a great challenge for the real-time monitoring of fish motion kinematics. Here, a multifunctional fish-wearable data snooping platform (FDSP) for studying fish kinematics is demonstrated based on an air sac triboelectric nanogenerator (AS-TENG) with antibacterial coating. The AS-TENG not only can harvest energy from fish swimming but also serves as the self-powered sensory module to monitor the swimming behavior of the fish.

A Self-Powered Dual-Type Signal Vector Sensor for Smart Robotics and Automatic Vehicles.

Automatic control systems are the most efficient technology for reducing labor cost while improving work efficiency. Vector motion monitoring is indispensable for the normal operation of automatic control systems. Here, a self-powered dual-type signal triboelectric nanogenerator (DS-TENG) is designed through integrating an alternating-current TENG and a direct-current TENG, which can monitor vector movement in real time based on pulse signal counts.

Seawater-Based Triboelectric Nanogenerators for Marine Anticorrosion.

The liquid-solid triboelectric nanogenerator is broadly studied for its self-powered sensing and blue energy harvesting, thanks to its low wear and highly efficient contact. However, the corresponding research studies focusing on deionized-water liquid-solid triboelectric nanogenerators (DL-TENGs) and seawater-type liquid-solid TENGs (SL-TENGs) are rarely being carried out at present. Here, a SL-TENG is fabricated by applying a dielectric film as the organic coating and coated and uncoated steel hull as the two electrodes.

Ultra-Stretchable and Fast Self-Healing Ionic Hydrogel in Cryogenic Environments for Artificial Nerve Fiber.

Self-healing materials behave with irreplaceable advantages in biomimetic intelligent robots (BIR) for avoiding or reducing safety hazards and economic losses from accidental damage during service. However, the self-healing ability is unreservedly lost and even becomes rigid and fragile in the cryogenic environment where BIR are precisely needed. Here, the authors report a versatile ionic hydrogel with fast self-healing ability, ultra-stretchability, and stable conductivity, even at -80 °C.

Stimulation of ambient energy generated electric field on crop plant growth.

Eco-friendly technologies are of great significance to agricultural sustainability due to the environmental damage caused by agricultural activities. Here, we report a wind and rain energy-driven electrical stimulation system for enhancing crop production. The system is based on an all-weather triboelectric nanogenerator (AW-TENG), which is composed of a bearing-and-hair structured triboelectric nanogenerator (TENG) and a raindrop-driven TENG.

Helical Fiber Strain Sensors Based on Triboelectric Nanogenerators for Self-Powered Human Respiratory Monitoring.

Respiration is a major vital sign, which can be used for early illness diagnosis and physiological monitoring. Wearable respiratory sensors present an exciting opportunity to monitor human respiratory behaviors in a real-time, noninvasive, and comfortable way. Among them, fiber-shaped triboelectric nanogenerators (FS-TENGs) are attractive for their comfort and high degree of freedom.

Emerging polymeric electrospun fibers: From structural diversity to application in flexible bioelectronics and tissue engineering.

Electrospinning (e-spin) technique has emerged as a versatile and feasible pathway for constructing diverse polymeric fabric structures, which show potential applications in many biological and biomedical fields. Owing to the advantages of adjustable mechanics, designable structures, versatile surface multi-functionalization, and biomimetic capability to natural tissue, remarkable progress has been made in flexible bioelectronics and tissue engineering for the sensing and therapeutic purposes. In this perspective, we review recent works on design of the hierarchically structured e-spin fibers, as well as, the fabrication strategies from one-dimensional individual fiber (1D) to three-dimensional (3D) fiber arrangements adaptive to specific applications.

A Self-Powered Triboelectric Hybrid Coder for Human-Machine Interaction.

Human-machine interfaces have penetrated various academia and industry fields such as smartphones, robotic, virtual reality, and wearable electronics, due to their abundant functional sensors and information interaction methods. Nevertheless, most sensors' complex structural design, monotonous parameter detection capability, and single information coding communication hinder their rapid development. As the frontier of self-powered sensors, the triboelectric nanogenerator (TENG) has multiple working modes and high structural adaptability, which is a potential solution for multi-parameter sensing and miniaturizing of traditional interactive electronic devices.

Advances in High-Performance Autonomous Energy and Self-Powered Sensing Textiles with Novel 3D Fabric Structures.

The seamless integration of emerging triboelectric nanogenerator (TENG) technology with traditional wearable textile materials has given birth to the next-generation smart textiles, i.e., textile TENGs, which will play a vital role in the era of Internet of Things and artificial intelligences.

Stretchable graded multichannel self-powered respiratory sensor inspired by shark gill.

Respiratory sensing provides a simple, non-invasive, and efficient way for medical diagnosis and health monitoring, but it relies on sensors that are conformal, accurate, durable, and sustainable working. Here, a stretchable, multichannel respiratory sensor inspired by the structure of shark gill cleft is reported. The bionic shark gill structure can convert transverse elastic deformation into longitudinal elastic deformation during stretching.

Density of Surface States: Another Key Contributing Factor in Triboelectric Charge Generation.

The triboelectric nanogenerator (TENG) has been invented as a technology for harvesting mechanical energy, as well as for allocating quantized charge for scientific instruments. The charge generation of the TENG is mainly related to the triboelectric effect or contact electrification (CE) as usually described by the potential-well-electron-cloud model, while the triboelectric charge transfer is related to the difference in the occupied energy levels of electrons. However, in our experiment, we observed an abnormal triboelectric charge generation phenomena between ternary materials, which cannot be explained by the occupied energy level difference only.

Trapezoidal Cantilever-Structure Triboelectric Nanogenerator Integrated with a Power Management Module for Low-Frequency Vibration Energy Harvesting.

Wide-band vibration is abundant in various industrial equipment, but extracting low frequency energy is challenging. Here, we demonstrated a trapezoidal cantilever-structure triboelectric nanogenerator (C-TENG) that can efficiently harvest energy from vibration in the range of 1-22 Hz. The C-TENG is fabricated with a flexible film electrode, and its mechanical model is analyzed with structural mechanics for the optimal performance of the device.

Bimodal Tactile Sensor without Signal Fusion for User-Interactive Applications.

Tactile sensors with multimode sensing ability are cornerstones of artificial skin for applications in humanoid robotics and smart prosthetics. However, the intuitive and interference-free reading of multiple tactile signals without involving complex algorithms and calculations remains a challenge. Herein a pressure-temperature bimodal tactile sensor without any interference is demonstrated by combining the fundamentally different sensing mechanisms of optics and electronics, enabling the simultaneous and independent sensing of pressure and temperature with the elimination of signal separation algorithms and calculations.

Rehabilitation of Total Knee Arthroplasty by Integrating Conjoint Isometric Myodynamia and Real-Time Rotation Sensing System.

As the world population structure has already exhibited an inevitable trend of aging, technical advances that can provide better eldercare are highly desired. Knee osteoarthritis, one of the most common age-associated diseases, can be effectively treated via total knee arthroplasty (TKA). However, patients are suffering from the recovery process due to inconvenience in post-hospital treatment.

Triboelectric Leakage-Field-Induced Electroluminescence Based on ZnS:Cu.

The related studies and applications of ZnS-based phosphorescent materials involve various aspects such as lighting, display, sensing, electronic signatures, and confidential information. Here, triboelectrification-induced electroluminescence (TIEL) of the ZnS:Cu due to the triboelectric leakage field is discovered via a gently horizontal sliding between a ZnS:Cu particle-doped polydimethylsiloxane (PDMS) film and a polytetrafluoroethylene (PTFE) or fluorinated ethylene propylene (FEP) film, whose intensity is positively correlated with the temperature, the doping ratio of ZnS:Cu, the pressure, and the frequency. It is also demonstrated that the TIEL mainly occurs inside the bulk film, where the ZnS:Cu phosphor particles can be polarized instantaneously by the leakage electric field of triboelectrification.

Stretchable Unsymmetrical Piezoelectric BaTiO 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 BaTiO 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.

Contact-electro-catalysis for the degradation of organic pollutants using pristine dielectric powders.

Mechanochemistry has been studied for some time, but research on the reactivity of charges exchanged by contact-electrification (CE) during mechanical stimulation remains scarce. Here, we demonstrate that electrons transferred during the CE between pristine dielectric powders and water can be utilized to directly catalyze reactions without the use of conventional catalysts. Specifically, frequent CE at Fluorinated Ethylene Propylene (FEP) - water interface induces electron-exchanges, thus forming reactive oxygen species for the degradation of an aqueous methyl orange solution.

Ferro-Pyro-Phototronic Effect in Monocrystalline 2D Ferroelectric Perovskite for High-Sensitive, Self-Powered, and Stable Ultraviolet Photodetector.

2D hybrid perovskite ferroelectrics have drawn great attention in the field of photodetection, because the spontaneous polarization-induced built-in electric field can separate electron-hole pairs, and makes self-powered photodetection possible. However, most of the 2D hybrid perovskite-based photodetectors focused on the detection of visible light, and only a few reports realized the self-powered and sensitive ultraviolet (UV) detection using wide bandgap hybrid perovskites. Here, 2D ferroelectric PMAPbCl monocrystalline microbelt (MMB)-based PDs are demonstrated.

Self-Powered Sensing for Non-Full Pipe Fluidic Flow Based on Triboelectric Nanogenerators.

Fluidic flow monitoring of a non-full pipe is of great significance in the field of energy measurement and pipeline transportation. In this work, a monitoring method based on triboelectric nanogenerators for non-full pipe fluidic flow of large pipelines is proposed. Specifically, a triboelectric non-full pipe flow sensor (TNPFS) is fabricated, which can monitor the flow velocity and the liquid level simultaneously, and then the flow can be obtained by conversion.

Enhanced Photoluminescence of Flexible InGaN/GaN Multiple Quantum Wells on Fabric by Piezo-Phototronic Effect.

Fabric-based wearable electronics are showing advantages in emerging applications in wearable devices, Internet of everything, and artificial intelligence. Compared to the one with organic materials, devices based on inorganic semiconductors (e.g.