Harvesting circuits for triboelectric nanogenerators for wearable applications

Micro energy harvesting for IoT platform: Review analysis toward future research opportunities

Micro-energy harvesting (MEH) is a technology of renewable power generation which is a key technology for hosting the future low-powered electronic devices for wireless sensor networks (WSNs) and, the Internet of Things (IoT). Recent technological advancements have given rise to several resources and technologies that are boosting particular facets of society. Many researchers are now interested in studying MEH systems for ultra-low power IoT sensors and WSNs. A comprehensive study of IoT will help to manage a single MEH as a power source for multiple WSNs. The popular database from Scopus was used in this study to perform a review analysis of the MEH system for ultra-low power IoT sensors. All relevant and important literature studies published in this field were statistically analysed using a review analysis method by VOSviewer software, and research gaps, challenges and recommendations of this field were investigated. The findings of the study indicate that there has been an increasing number of literature studies published on the subject of MEH systems for IoT platforms throughout time, particularly from 2013 to 2023. The results demonstrate that 67% of manuscripts highlight problem-solving, modelling and technical overview, simulation, experimental setup and prototype. In observation, 27% of papers are based on bibliometric analysis, systematic review, survey, review and based on case study, and 2% of conference manuscripts are based on modelling, simulation, and review analysis. The top-cited articles are published in 5 different countries and 9 publishers including IEEE 51%, Elsevier 16%, MDPI 10% and others. In addition, several MEH system-related problems and challenges are noted to identify current limitations and research gaps, including technical, modelling, economic, power quality, and environmental concerns. Also, the study offers guidelines and recommendations for the improvement of future MEH technology to increase its energy efficiency, topologies, design, operational performance, and capabilities. This study's detailed information, perceptive analysis, and critical argument are expected to improve MEH research's viable future.

Energy-efficient electronics with an air-friction-driven rotating gate transistor using tribotronics

Concern for the environment is one of the main factors that are increasing the demand for compact and energy-efficient electronic devices. Recent research has made advances in reducing the power consumption of field-effect transistors, including the use of high-dielectric insulators, low-voltage operation, and selective power-conservation strategies. This paper introduces a revolutionary air-friction-driven rotating gate transistor that operates without the need for a conventional gate voltage. This new device offers the advantages of wear resistance, a slim and flexible design (achieved through low-temperature solution processing), and a simplified three-layer structure that streamlines manufacturing and reduces potential carbon emissions. This device's wear resistance and ease of fabrication render the device a promising technology with applications in various fields, including electronics, vehicles, aviation, and wearable devices. This study provides evidence of the device's feasibility for use in real-world vehicular scenarios, underscoring its potential for future innovation and widespread adoption.

Advanced Self-Powered Biofuel Cells with Capacitor and Nanogenerator for Biomarker Sensing

Self-powered biofuel cells (BFCs) have evolved for highly sensitive detection of biomarkers such as noncodon micro ribonucleic acids (miRNAs) in the presence of interfering substrates. Self-charging supercapacitive BFCs for in vivo and in vitro cellular microenvironments represent the most prevalent sensing mechanism for diagnosis. Therefore, self-powered biosensing (SPB) with a capacitor and contact separation with a triboelectric nanogenerator (TENG) offers electrochemical and colorimetric dual-mode detection via improved electrical signal intensity. In this review, we discuss three major components: stretchable self-powered BFC design, miRNA sensing, and impedance spectroscopy. A specific focus is given to 1) assembling of sensors for biomarkers, 2) electrical output signal intensification, and 3) role of supercapacitors and nanogenerators in SPBs. We outline the key features of stretchable SPBs and the sequence of miRNA sensing by SPBs. We have emphasized the need of a supercapacitor and nanogenerator for SPBs in the context of advanced assembly of the sensing unit. Finally, we outline the role of impedance spectroscopy in the detection and estimation of biomarkers. We highlight key challenges in SPBs for biomarker sensing, which needs improved sensing accuracy, integration strategies of electrochemical biosensing for in vitro and in vivo microenvironments, and the impact of miRNA sensing on cancer diagnostics. This article attempts a specific focus on the accuracy and limitations of sensing unit for miRNA biomarkers and associated tool for boosting electrical signal intensity for a potential big step further.

Textile-type triboelectric nanogenerator using Teflon wrapping wires as wearable power source

Wearable electronic devices such as mobile communication devices, portable computers, and various sensors are the latest significant innovations in technology which use the Internet of Things (IoT) to track personal data. Wearable energy harvesters are required to supply electricity to such devices for the convenience of users. In this study, a textile-type triboelectric nanogenerator (T-TENG), produced using commercial electrode fibers, was fabricated to generate electrical energy using external mechanical stimulation. The commercial fiber was an electrode coated with Teflon on a copper wire with a diameter of ~ 320 μm. Using this commercial fiber, a T-TENG was easily fabricated by knitting and weaving. The performance of the T-TENG was analyzed to understand the effect of force and frequency. It was observed that the performance of the T-TENG did not degrade even under harsh conditions and treatment. The textile-type TENG possessed an energy harvesting capability with an output power density of ~ 0.36 W/m2 and could operate electronic devices by charging a capacitor.