Structural Flexibility in Triboelectric Nanogenerators: A Review on the Adaptive Design for Self-Powered Systems

Abstract

There is an increasing need for structural flexibility in self-powered wearable electronics and other Internet of Things (IoT), where adaptable triboelectric nanogenerators (TENGs) play a key role in realizing the true potential of IoT by endowing the latter with self-sustainability. Thus, in this review, the topic was restricted to the adaptive design of TENGs with structural flexibility that aims to promote the sustainable operation of various smart electronics. This review begins with an emphatical discussion of the concept of flexible electronics and TENGs, and continues with the introduction of TENG-based self-powered intelligent systems while placing the emphasis on self-powered flexible intelligent devices. Self-powered healthcare sensors, e-skins, and other intelligent wearable electronics with enhanced intelligence and efficiency in practical applications due to the integration with TENGs are illustrated, along with an emphasis on the design strategy of structural flexibility of TENGs and the associated integration schemes. This review aims to cover recent achievements in the field of self-powered systems, and provides information on how flexibility or adaptability in TENGs can be adopted, their types, and why they are required in promoting advanced IoT applications with sustainability and intelligence algorithms.

Biophysical Sensors Based on Triboelectric Nanogenerators

“…For medical applications, the fabrication of high-quality TENGs is closely related to the selection of reliable and biodegradable/biocompatible materials, whose surface structure, polarity, and microstructure can significantly affect the output performance of devices manufactured from these materials [ 50 ]. As a result, how to achieve excellent output performance while ensuring other characteristics such as biological description, stability, flexibility, etc.…”

Self-Powered Phase Transition Driven by Triboelectric Nanogenerator

“…Due to their scalability, portability, low cost, and high compatibility, TENGs have been widely used in various self-powered systems, from integrated displays to wearable healthcare electronic devices. 26 In this work, we selected BM-SCO as the phase transition material, and BM-SCO was deposited on the SrTiO 3 (STO) substrate by pulsed laser deposition (PLD). Then, we used the TENG as a self-powered system to prepare an electric-fieldcontrolled IL gating device.…”

“…Wang et al combined a friction nanogenerator with a VO 2 film as the gate and channel of the device, realizing electronic doping-induced phase modulation of the VO 2 material by the triboelectric effect and electrical induction, which expanded a new method to apply TENGs in electronic transistors and new electronic doping technologies. Due to their scalability, portability, low cost, and high compatibility, TENGs have been widely used in various self-powered systems, from integrated displays to wearable healthcare electronic devices …”

Biodegradable Polymers in Triboelectric Nanogenerators

“…In current era, the rapid growth of the internet of things (IoTs) represented by wearable electronic devices and wireless sensor networks has changed every aspect of our daily life, such as health monitoring, medical treatment, communication, entertainment, transportation, environmental protection, infrastructure monitoring, and security [ 1 , 2 , 3 , 4 ]. However, in order to ensure reliable and continuous operation of the sensing nodes, so as to realize the full power of IoTs, there arises an urgent demand for prosperous and sustainable energy harvesting devices which can scavenge energies from the ambient environment or our body and charge energy storage devices in a continuous way [ 5 , 6 , 7 , 8 , 9 ]. Meanwhile, there is also a rising dependence of advanced health monitoring and therapeutic technologies on biocompatibility or biodegradability, where biodegradable electronic components can be degraded and disintegrated into monomeric and oligomeric building blocks, thereby reducing their environmental and physiological impacts [ 10 , 11 , 12 , 13 ].…”