Bioinspired Designs and Biomimetic Applications of Triboelectric Nanogenerators

The emerging novel power generation technology of triboelectric nanogenerators (TENGs) is attracting increasing attention due to its unlimited prospects in energy harvesting and self-powered sensing applications. The most important factors that determine TENGs’ electrical and mechanical performance include the device structure, surface morphology and the type of triboelectric material employed, all of which have been investigated in the past to optimize and enhance the performance of TENG devices. Amongst them, bioinspired designs, which mimic structures, surface morphologies, material properties and sensing/power generation mechanisms from nature, have largely benefited in terms of enhanced performance of TENGs. In addition, a variety of biomimetic applications based on TENGs have been explored due to the simple structure, self-powered property and tunable output of TENGs. In this review article, we present a comprehensive review of various researches within the specific focus of bioinspired TENGs and TENG enabled biomimetic applications. The review begins with a summary of the various bioinspired TENGs developed in the past with a comparative analysis of the various device structures, surface morphologies and materials inspired from nature and the resultant improvement in the TENG performance. Various ubiquitous sensing principles and power generation mechanisms in use in nature and their analogous artificial TENG designs are corroborated. TENG-enabled biomimetic applications in artificial electronic skins and neuromorphic devices are discussed. The paper concludes by providing a perspective towards promising directions for future research in this burgeoning field of study

Nanogenerators from Electrical Discharge

Electrical discharge is generally considered as a negative effect in the electronic industry and often causes electrostatic discharge (ESD) and thus failure of electronic components and integrated circuits (IC). However, this effect was recently used to develop a new energy-harvesting technology, direct-current triboelectric nanogenerator (DC-TENG). In this chapter, its fundamental mechanism and the working modes of the nanogenerator will be presented. They are different from the general alternating current TENG (AC-TENG) invented in 2012, which is based on triboelectrification and electrostatic induction. Taking advantage of the electrostatic discharge, it can not only promote the miniaturization trend of TENG and self-powered systems, but also provide a paradigm shifting technique to in situ gain electrical energy

Piezo-phototronic Effect Enhanced Photodetector Based on MAPbI3 Perovskite

Recent research on hybrid organic–inorganic perovskites has greatly advanced the fields of photovoltaics, photodetection, and light emission. The emergence of piezotronics and piezo-phototronics has led to tremendous high-performance devices that are based on piezoelectric materials. Although many previous research studies were centered around single crystal hybrid perovskites, polycrystalline materials are easier to fabricate, such as by using a solution-process, and have many other advantages, e.g. low cost, low environmental requirements, and high conversion efficiency. So far, there are very few reports of piezotronically modulated polycrystalline perovskite devices. Here, a novel piezo-phototronic effect enhanced photodetector based on MAPbI3 polycrystalline perovskite is designed, fabricated, and subsequently characterized. With polycrystalline materials, it is seen that the device performances can be significantly enhanced using the piezo-phototronic effect. Moreover, the polycrystalline perovskite introduces unprecedented potential to fine tune the devices from weak to strong piezoelectric performance. Our study explores the possibility of using polycrystalline perovskites to create high performance strain-controlled piezo-phototronic devices, which will have promising applications in the internet of things, multifunctional micro/nanoelectromechanical devices and sensor networks

Piezo-Tribo Dual Effect Hybrid Nanogenerators for Health Monitoring

Over the years, nanogenerators for health monitoring have become more and more attractive as they provide a cost-effective and continuous way to successfully measure vital signs, physiological status, and environmental changes in/around a person. Using such sensors can positively affect the way healthcare workers diagnose and prevent life-threatening conditions. Recently, the dual piezo-tribological effect of hybrid nanogenerators (HBNGs) have become a subject of investigation, as they can provide a substantial amount of data, which is significant for healthcare. However, real-life exploitation of these HBNGs in health monitoring is still marginal. This review covers piezo-tribo dual-effect HBNGs that are used as sensors to measure the different movements and changes in the human body such as blood circulation, respiration, and muscle contractions. Piezo-Tribo dual-effect HBNGs are applicable within various healthcare settings as a means of powering noninvasive sensors, providing the capability of constant patient monitoring without interfering with the range of motion or comfort of the user. This review also intends to suggest future improvements in HBNGs. These include incorporating surface modification techniques, utilizing nanowires, nanoparticle technologies, and other means of chemical surface modifications. These improvements can contribute significantly in terms of the electrical output of the HBNGs and can enhance their prospects of applications in the field of health monitoring, as well as various in vitro/in vivo biomedical applications. While a promising option, improved HBNGs are still lacking. This review also discusses the technical issue which has prevented so far, the real use of these sensors

Self-powered on-line ion concentration monitor in water transportation driven by triboelectric nanogenerator

The final publication is available at Elsevier via https://doi.org/10.1016/j.nanoen.2019.05.029. © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Ion concentration in water is a key criterion for evaluating water quality. In this work, we developed a self-powered on-line ion concentration monitor in water transportation based on impedance matching effect of triboelectric nanogenerator (TENG). A rotary disc-shaped TENG (RD-TENG) and an ion concentration sensor were fabricated based on the industrial printed circuit board (PCB) technology. Flowing water in the pipeline acts as the energy source to drive the RD-TENG and generate an open-circuit (Voc) of 210 V. The ion concentration sensor exhibits a nearly pure resistance characteristic under the alternating current (AC) signal with the frequency below 500 Hz, corresponding to the rotation speed of 250 rpm for the RD-TENG. The impedance matching relationship between the RD-TENG and the ion concentration sensor was experimentally studied and applied to elucidate the sensing mechanism. Finally, a self-powered sensing system integrated with an alarm circuit was assembled which exhibits excellent responsibility and high sensitivity. The change of ion concentration with only 1 × 10−5 mol/L can light up an alarm LED.Natural Science and Engineering Research CouncilCanada Research ChairsNational Natural Science Foundation of China, no. 61804103National Key R&D Program of China, no. 2017YFA0205002Natural Science Foundation of the Jiangsu Higher Education Institutions of China, no. 18KJA535001, no. 14KJB150020Natural Science Foundation of Jiangsu Province of China, no. BK20170343, no. BK20180242China Postdoctoral Science Foundation, no. 2017M610346Collaborative Innovation Center of Suzhou Nano Science & TechnologyPriority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)111 Projec

Large-Area Soft e-Skin: The Challenges Beyond Sensor Designs

Sensory feedback from touch is critical for many tasks carried out by robots and humans, such as grasping objects or identifying materials. Electronic skin (e-skin) is a crucial technology for these purposes. Artificial tactile skin that can play the roles of human skin remains a distant possibility because of hard issues in resilience, manufacturing, mechanics, sensorics, electronics, energetics, information processing, and transport. Taken together, these issues make it difficult to bestow robots, or prosthetic devices, with effective tactile skins. Nonetheless, progress over the past few years in relation with the above issues has been encouraging, and we have achieved close to providing some of the abilities of biological skin with the advent of deformable sensors and flexible electronics. The naive imitation of skin morphology and sensing an impoverished set of mechanical and thermal quantities are not sufficient. There is a need to find more efficient ways to extract tactile information from mechanical contact than those previously available. Renewed interest in neuromorphic tactile skin is expected to bring some fresh ideas in this field. This article reviews these new developments, particularly related to the handling of tactile data, energy autonomy, and large-area manufacturing. The challenges in relation with these advances for tactile sensing and haptics in robotics and prosthetics are discussed along with potential solutions

Development of Triboelectric Devices for Self-powered Sensing And Energy Harvesting Applications

Due to the bulky size and limited lifespan of batteries, remote charging and energy har- vesting from the environment are becoming two trends to power miniaturized electronics. Tri- boelectric nanogenerator (TENG) is an emerging technology to convert mechanical energy to electricitical energy by the coupling of triboelectrification and electrostatic induction. It has been widely applied to self-powered sensing and energy generation by virtue of the simpler device configuration and broader material choices compared to conventional energy conversion technologies, such as electromagnetic and piezoelectric energy harvesters. In this thesis, it is the first time to presented a self-powered on-line ion concentration monitoring system based on the impedance matching effect of TENG. Other than handcrafted TENGs, the rotary disc-shaped TENG (RD-TENG) was fabricated by the industrial printed circuit board (PCB) technology, which could realize sophisticated design and low-cost fabrica- tion. Flowing water, as the energy source, in the pipeline was utilized to drive the RD-TENG and generate an open-circuit voltage (VOC) of ∼210 VP−P. The impedance matching effect of TENG as the sensing mechanism was studied thoroughly. Based on the impedance matching effect, an alarm circuit was designed for the demonstration and the alarm LED can be success- fully lit up by the change of NaCl concentration with only 1×10−5 mol/L, which showed a high sensitivity. Compared to environmental monitoring, healthcare monitoring requires further miniatur- ized size and better compatibility with electronics. To satisfy the demands, a novel micro tri- boelectric energy harvester (μTEH) was developed. Based on the μTEH, a propotyped acoustic energy transfer system was built via an ultrasound link. For the very first time, TENG was fab- ricated by Micro-electro-mechanical systems (MEMS) technologies in batch process, giving better integrated circuit (IC) integration. More importantly, it is also the first time that the size of TENG is brought into microscale. We demonstrated a prototyped acoustic energy transfer system for implanted devices that could generate 50 nW power on load resistor under 1 MHz, 132 mW/cm2 incident acoustic power. The μTEH also achieved a signal-to-ratio (SNR) of 20.54 dB and exhibited promising potential for wireless communication by modulating the in- cident ultrasound. Finally, detailed optimization methods were proposed to improve the output power of the μTEHs in the future