Self-Powered Sensing in Wearable Electronics─A Paradigm Shift Technology

Self-Powered Strain Sensing via Ion Physisorption at PVC Ion Gel─Metal Interfaces

Self-powered strain sensors are crucial for wearable technology and low-power applications, where continuous operation with minimal energy is essential. Conventional sensors typically require external power, leading to bulky designs, limited battery life, and frequent maintenance, which hinder seamless integration into wearable devices. This study introduces an ion physisorption-based self-powered strain sensor (IPSS) enabling stable, strain-induced voltage measurements without external power. The IPSS leverages the physical adsorption of [EMIM] cations in a PVC ion gel onto electrode surfaces, generating a measurable voltage difference under strain. Potential of zero charge measurements confirmed selective ion adsorption based on electrode work functions, validating the IPSS's operating mechanism. Notably, the IPSS demonstrated a broad operational range of 0-200% strain with a linear response of 2.3 mV/% in the low-strain range (0-40%), highlighting its precision for wearable applications. Using the IPSS's stable, self-powered signal, a CNN-based gesture recognition model achieved 92% accuracy with just 0.00507 GFLOPs, showing the sensor's potential for low-power, high-accuracy applications in wearable and resource-limited environments.

Self-Powered Switchable Gas-Humidity Difunctional Flexible Chemosensors Based on Smart Adaptable Hydrogel

The development of self-powered, flexible, and multi-function sensors is highly anticipated in wearable electronics, however, it remains a daunting challenge to identify different signals based on a single device with singular sensing material without algorithmic support. Here, a smart adaptable hydrogel is developed by co-introducing two ions with vastly different hydrophilicity for the construction of an electrochemically self-powered, flexible, and reversibly switchable difunctional chemosensor with a metal-air battery structure. The prepared hydrogel can readily switch between water-rich and water-deficient states for crosstalk-free detection of oxygen and humidity respectively, since O2 gas and water molecules can directly participate in the oxygen reduction reaction in the device and act alone as limiting reactants and catalysts to affect the reaction rate under different hydrogel states. The resulting sensor demonstrates breakthrough O2 and humidity sensing performance with sensitivities as high as 4170.5%/% and 380.2%/% RH in water-rich and water-deficient states, respectively, and ultrawide detection ranges. Thanks to these, the devices can be applied for real-time and remote monitoring of ambient oxygen, transcutaneous oxygen pressure changes, respiration, and skin moisture by combining with wireless communication technology, and therefore have important application prospects in the fields of safety, health management, and non-contact human-machine interaction.

Radical-activable charge-transfer cocrystals for solar thermoelectric generator toward information conversion

Solar thermoelectric generators (STEGs) that can effectively harvest solar energy and convert it into affordable electricity, provide a promising solution for self-powered wearable electronics and the Internet of Things (IoT). However, their electricity generation is often limited by the low thermal concentration or unstable temperature gradients in practical applications. Herein, we rationally designed an organic radical-activable charge-transfer (CT) cocrystal based on the open-shell radical electron acceptor of 2,6-dibromonaphthalene-1,4,5,8-tetracarboxylic dianhydride. The open-shell radical contributes to the strong near-infrared absorption and nonradiative recombination, resulting in a high photothermal conversion efficiency of 67.2% for the prepared CT cocrystal. Furthermore, the photothermal ink containing the radical-activable CT cocrystal and the transparent resin was successfully coated onto a thermoelectric generator as a cost-effective light absorber, facilely forming a high-performance STEG. Notably, the prepared STEG output a voltage of 143 mV under 1 sun irradiation, demonstrating real-time photodetection capability. We anticipate the potential applications of these cocrystals in self-powered optoelectronics, such as a non-contact and long-distance information converters.

Human bio-electric generator: Self-powered cellulose-based wearable sensor with ultra-stretchability and low-grade body heat harvesting

Integrating ultra-stretchability to adapt seamlessly to human movement, while ensuring complete independence from external power sources, presents a substantial challenge for the development of advanced bioelectronic systems. This challenge becomes even more critical as the demand for wearable technologies that can both harvest energy and monitor physiological signals grows. In response to these needs, we introduce a bio-flexible thermoelectric gel composed of microcrystalline cellulose (MCC) and poly (deep eutectic solvent) (PDES), which is synthesized via a simple one-pot method for body heat harvesting in self-powered sensors. The resulting sensor demonstrates impressive performance: a Seebeck coefficient of 25.86 mV K-1, low thermal conductivity of 0.2972 W m-1 K-1and a ZT value of 0.27 at room temperature. Additionally, it exhibits remarkable mechanical flexibility, with an elongation at break of 2080 %, making it highly suitable for detecting significant bodily deformations. The supramolecular hydrogen bonding network within gel ensures excellent mechanical properties and sensing sensitivity even at low temperatures (∼249.15 K). Overall, PDES-MCC2% sensor holds great potential for smart wearable applications like generators, respiratory monitoring and motion optimization, marking a significant step toward truly autonomous, sustainable bioelectronic systems that could revolutionize daily tech interaction.

An 8-Micrometer-Thick Film Strain Sensor with Conformal 3D Microstructure for Accurate Detection of Body Motion and Air Leakage

Elastomer-based resistive super-thin film strain sensors show great application potentials in electronic skins, human-machine interaction systems, wearable devices for healthcare, and machine learning algorithms. However, it is challenging to accurately monitor the deformation of human body joints and organs with curved surfaces (e.g., knees, throats, finger joints) by only taking advantage of material thickness and elasticity of conventional 2D film strain sensors. Herein, a simple strategy is developed to fabricate conformal elastomeric thin film sensors with periodic 3D microstructure inspired by the ridges and valleys of human skin for accurate signal acquisition. Specifically, an 8-micrometer-thick elastic film strain sensor with 3D microstructure is fabricated via thermoforming followed by in situ chemical growth of silver nanoparticles. The 3D film strain sensors exhibit excellent signal linearity (R2 = 0.99) and relatively high sensitivity (gauge factor = 14) over a relatively wide strain range (≈43%), with an ultra-low strain detection limit of 0.025%, enabling potential applications in human healthcare monitoring and air leakage detection. Thus, this study unveils a simple methodology to process microstructure-enabled conformable 3D film strain sensors, which show good conformability and multiple mechanical sensing functions for advancing the development of next-generation flexible strain sensors.

In Situ Polarization Enables Dipole Alignment of α-Phase Polyamide 11 Nanoribbons for Breathable Triboelectric Textile

Triboelectric textiles have been extensively studied for wearable energy applications, including single-fiber power generation, humidity-resistant power generation, air-breakdown-based power generation, etc. However, intrinsic tribo-charge transfer in fiber- or textile-based triboelectric materials remains at a low level. Here, we propose a polarization strategy to enhance triboelectric performance using α-phase polyamide 11 nanoribbons. By employing a high-voltage electrostatic field during electrospinning, we achieve in situ polarization of polyamide 11, resulting in an 116% improvement in the performance of polyamide 11-based energy nonwovens. Additionally, we apply cold pressing to optimize the specific surface area and air permeability of the all-fiber-energy nonwoven, achieving a balance of high electrical performance and wearability. We further demonstrate applications of this nanofiber-based energy textile in wireless sensing and breathable energy insoles. This all-fiber performance enhancement strategy provides valuable insights for the development of high-performance triboelectric textiles in the future.

Wearable textile sensors for continuous glucose monitoring

Diabetes and cardiovascular disease are interlinked chronic conditions that necessitate continuous and precise monitoring of physiological and environmental parameters to prevent complications. Non-invasive monitoring technologies have garnered significant interest due to their potential to alleviate the current burden of diabetes and cardiovascular disease management. However, these technologies face limitations in accuracy and reliability due to interferences from physiological and environmental factors. This review investigates electronic textiles (e-textiles) that integrate biomedical sensors into wearable fabrics that can enable a multimodal platform for non-invasive continuous glucose monitoring (CGM). Current advancements in e-textiles show the potential of four key methods for glucose monitoring: optical, biochemical, biomechanical, and thermal sensing techniques. Biochemical sensing through sweat-based glucose detection has demonstrated potential for accurate and non-invasive monitoring but still faces numerous challenges. While optical, biomechanical and thermal sensing are less explored in e-textiles, they offer additional physiological and environmental insights that can improve the precision of glucose readings by providing cross-validation of data. This review proposes that integrating multiple sensing modalities into a single multimodal e-textile wearable can address the accuracy and reliability challenges by providing cross-validation of data. The development of such multimodal e-textiles has the potential to revolutionise diabetes and cardiovascular disease management by providing continuous, accurate, and holistic monitoring in real-time, which could significantly improve patient outcomes and quality of life. Further research and development are crucial to fully realise the potential of these integrated systems in clinical and everyday settings.

Exploring the Synergistic Effects of MoS2 and PVDF for Advanced Piezoelectric Sensors: A First-Principles Approach

Flexible wearable electronic devices have found widespread applications in health monitoring and human-machine interaction. Piezoelectric sensors, capable of converting mechanical stress into electrical signals, serve as critical components in these systems. In this study, we enhanced the piezoelectric performance of PVDF-based composite materials through MoS2 incorporation. Experimental results demonstrated that MoS2 addition effectively increased the β-phase content in PVDF, achieving a maximum value of 70.0% at an optimal MoS2 concentration of 0.75 wt%. Density functional theory (DFT) calculations revealed that while β-phase PVDF possesses slightly higher energy than other phases, it exhibits stronger adsorption interactions and enhanced charge transfer with MoS2, thereby promoting β-phase formation. The fabricated MoS2/PVDF composite nanofiber film maintained stable voltage output under repeated mechanical stress through 2000 operational cycles. When implemented as a body-mounted sensor, the composite material demonstrated exceptional responsiveness to human motions, confirming its practical potential for wearable electronics applications.

Hydrogen Peroxide Fuel Cells and Self-Powered Electrochemical Sensors Based on the Principle of a Fuel Cell with Biomimetic and Nanozyme Catalysts

The operating principle of a fuel cell is attracting increasing attention in the development of self-powered electrochemical sensors (SPESs). In this type of sensor, the chemical energy of the analyzed substance is converted into electrical energy in a galvanic cell through spontaneous electrochemical reactions, directly generating an analytical signal. Unlike conventional (amperometric, voltammetric, and impedimetric) sensors, no external energy in the form of an applied potential is required for the redox detection reactions to occur. SPESs therefore have several important advantages over conventional electrochemical sensors. They do not require a power supply and modulation system, which saves energy and costs. The devices also offer greater simplicity and are therefore more compatible for applications in wearable sensor devices as well as in vivo and in situ use. Due to the dual redox properties of hydrogen peroxide, it is possible to develop membraneless fuel cells and fuel-cell-based hydrogen peroxide SPESs, in which hydrogen peroxide in the analyzed sample is used as the only source of energy, as both an oxidant and a reductant (fuel). This also suppresses the dependence of the devices on the availability of oxygen. Electrode catalyst materials for different hydrogen peroxide reaction pathways at the cathode and the anode in a one-compartment cell are a key technology for the implementation and characteristics of hydrogen peroxide SPESs. This article provides an overview of the operating principle and designs of H2O2-H2O2 fuel cells and H2O2 fuel-cell-based SPESs, focusing on biomimetic and nanozyme catalysts, and highlights recent innovations and prospects of hydrogen-peroxide-based SPESs for (bio)electrochemical analysis.

Synthesis of shape-tunable PbZrTiO3 nanocrystals with lattice variations for piezoelectric energy harvesting and human motion detection

PbZr0.7Ti0.3O3 cubes with tunable sizes and cuboids have been hydrothermally synthesized. PbZrTiO3 cubes with three different Zr : Ti atomic percentages were also prepared. Analysis of synchrotron X-ray diffraction (XRD) patterns reveals the presence of two lattice components for these samples. Fast Fourier Transform (FFT) processing of high-resolution transmission electron microscopy (HR-TEM) images shows discernible lattice spot differences between the inner bulk and surface layer region for a PbZr0.7Ti0.3O3 cube, while a cuboid has distinct lattice spot deviations. The lattice variations yield different dielectric constant numbers for these two samples, despite being bound by the same crystal faces. The PbZrTiO3 crystals give size- and composition-dependent band gaps. Cuboids show notably larger piezoelectric and ferroelectric responses than cubes. Piezoelectric nanogenerators (PENGs) containing 30 wt% cuboids produce the highest open-circuit voltage of 20.36 V and short-circuit current of 2300 nA. The PENGs harvest energy through bending/releasing cycles to power devices and show photothermal pyroelectric activity. Moreover, a single 30 wt% cuboid PENG device integrated into a shoe insole can deliver an impressive 96.8% accuracy for human motion detection using a machine learning approach. This work illustrates that considerable lattice variation through crystal shape control is effective in enhancing material properties.

Advances in integrated power supplies for self-powered bioelectronic devices

Bioelectronic devices with medical functions have attracted widespread attention in recent years. Power supplies are crucial components in these devices, which ensure their stable operation. Biomedical devices that utilize external power supplies and extended electrical wires limit patient mobility and increase the risk of discomfort and infection. To address these issues, self-powered devices with integrated power supplies have emerged, including triboelectric nanogenerators, piezoelectric nanogenerators, thermoelectric generators, batteries, biofuel cells, solar cells, wireless power transfer, and hybrid energy systems. This mini-review highlights the recent advances in the power supplies utilized in these self-powered devices. A concluding section discusses the subsisting challenges and future perspectives in integrated power supply technologies and design and manufacturing of self-powered devices.

Nanomaterials for Flexible Neuromorphics

The quest to imbue machines with intelligence akin to that of humans, through the development of adaptable neuromorphic devices and the creation of artificial neural systems, has long stood as a pivotal goal in both scientific inquiry and industrial advancement. Recent advancements in flexible neuromorphic electronics primarily rely on nanomaterials and polymers owing to their inherent uniformity, superior mechanical and electrical capabilities, and versatile functionalities. However, this field is still in its nascent stage, necessitating continuous efforts in materials innovation and device/system design. Therefore, it is imperative to conduct an extensive and comprehensive analysis to summarize current progress. This review highlights the advancements and applications of flexible neuromorphics, involving inorganic nanomaterials (zero-/one-/two-dimensional, and heterostructure), carbon-based nanomaterials such as carbon nanotubes (CNTs) and graphene, and polymers. Additionally, a comprehensive comparison and summary of the structural compositions, design strategies, key performance, and significant applications of these devices are provided. Furthermore, the challenges and future directions pertaining to materials/devices/systems associated with flexible neuromorphics are also addressed. The aim of this review is to shed light on the rapidly growing field of flexible neuromorphics, attract experts from diverse disciplines (e.g., electronics, materials science, neurobiology), and foster further innovation for its accelerated development.

Self-Adhesive and Self-Sustainable Bioelectronic Patch for Physiological Feedback Electronic Modulation of Soft Organs

Bionic electrical stimulation (Bio-ES) aims to achieve personalized therapy and proprioceptive adaptation by mimicking natural neural signatures of the body, while current Bio-ES devices are reliant on complex sensing and computational simulation systems, thus often limited by the low-fidelity of simulated electrical signals, and failure of interface information interaction due to the mechanical mismatch between soft tissues and rigid electrodes. Here, the study presents a flexible and ultrathin self-sustainable bioelectronic patch (Bio-patch), which can self-adhere to the lesion area of organs and generate bionic electrical signals synchronized vagal nerve envelope in situ to implement Bio-ES. It allows adaptive adjustment of intensity, frequency, and waveform of the Bio-ES to fully meet personalized needs of tissue regeneration based on real-time feedback from the vagal neural controlled organs. With this foundation, the Bio-patch can effectively intervene with excessive fibrosis and microvascular stasis during the natural healing process by regulating the polarization time of macrophages, promoting the reconstruction of the tissue-engineered structure, and accelerating the repair of damaged liver and kidney. This work develops a practical approach to realize biomimetic electronic modulation of the growth and development of soft organs only using a multifunctional Bio-patch, which establishes a new paradigm for precise bioelectronic medicine.

Multi-Interface Engineering of MXenes for Self-Powered Wearable Devices

Self-powered wearable devices with integrated energy supply module and sensitive sensors have significantly blossomed for continuous monitoring of human activity and the surrounding environment in healthcare sectors. The emerging of MXene-based materials has brought research upsurge in the fields of energy and electronics, owing to their excellent electrochemical performance, large surface area, superior mechanical performance, and tunable interfacial properties, where their performance can be further boosted via multi-interface engineering. Herein, a comprehensive review of recent progress in MXenes for self-powered wearable devices is discussed from the aspects of multi-interface engineering. The fundamental properties of MXenes including electronic, mechanical, optical, and thermal characteristics are discussed in detail. Different from previous review works on MXenes, multi-interface engineering of MXenes from termination regulation to surface modification and their impact on the performance of materials and energy storage/conversion devices are summarized. Based on the interfacial manipulation strategies, potential applications of MXene-based self-powered wearable devices are outlined. Finally, proposals and perspectives are provided on the current challenges and future directions in MXene-based self-powered wearable devices.

Advanced Flexible Physical Sensors with Independent Detection Mechanisms of Pressure and Strain Stimuli for Overcoming Signal Interference

Flexible and wearable physical sensors have gained significant interest owing to their potential in attachable devices, electronic skin, and multipurpose sensors. The physical stimuli of these sensors typically consist of vertically and horizontally applied pressures and strains, respectively. However, owing to their similar response characteristics, interference occurs between the two types of signals detected, complicating the distinction between pressure and strain stimuli, leading to inaccurate data interpretation and reduced sensor specificity. Therefore, we developed a dual-sensing-mode physical sensor with separate response mechanisms for the two types of physical stimuli based on a unique structural design that can independently induce changes in the piezocapacitance and piezoresistance for pressure and strain stimuli, respectively. The asterisk-shaped piezoresistive pathway (electrode), designed for multifunctionality, effectively detected the intensity and direction of tensile deformation, and an elastomeric sponge structure positioned between the two electrodes detected the pressure signals via changes in capacitance. This dual-sensing-mode sensor offers clearer signal differentiation and enhanced multifunctionality compared to those of traditional single-mode sensors. Additionally, extensive experimentation demonstrated that our sensor has a good sensitivity, high linearity, and stability in detecting signals, proving its applicability for sophisticated monitoring and control tasks that require the differential detection between pressure and deformation signals.

Enhanced Performance of a Self-Powered Au/WSe2/Ta2NiS5/Au Heterojunction by the Interfacial Pyro-phototronic Effect

The growing need for wearable electronics and self-powered electronic devices has driven the successful development of self-powered two-dimensional (2D) photodetectors using the photovoltaic effect of Schottky and p-n junctions. However, there is an urgent need to develop multifunctional photodetectors capable of harvesting energy from different sources to overcome their limitations in efficiency and cost. While the pyro-phototronic effect has been shown to effectively influence optoelectronic processes in heterojunctions, the number of reported two-dimensional heterojunctions exhibiting interfacial pyroelectricity is still limited, and the responsivity and detectivity based on such heterojunctions tend to be low. In this study, a photodetector based on an Au/WSe2/Ta2NiS5/Au heterojunction was designed and fabricated. By harnessing the interfacial pyro-phototronic effect arising from the built-in electric fields at the Au/WSe2 Schottky junction and WSe2/Ta2NiS5 heterojunction, the photodetector exhibits a broadband response range of 405-1064 nm, with approximately 12 times enhancement in output current compared to solely relying on the photovoltaic effect. Under 660 nm light irradiation, the self-powered photodetector exhibits a responsivity of 121 mA/W, an external quantum efficiency of 22.64%, and a specific detectivity of 2 × 1012 Jones. Notably, its pyroelectric coefficient exceeds 8 × 103 μC·m-2·K-1. These findings pave the way for effectively detecting weak light and temperature variation while presenting a new strategy for developing high-performance photodetectors utilizing the interfacial pyro-phototronic effect.

Toward an AI Era: Advances in Electronic Skins

Electronic skins (e-skins) have seen intense research and rapid development in the past two decades. To mimic the capabilities of human skin, a multitude of flexible/stretchable sensors that detect physiological and environmental signals have been designed and integrated into functional systems. Recently, researchers have increasingly deployed machine learning and other artificial intelligence (AI) technologies to mimic the human neural system for the processing and analysis of sensory data collected by e-skins. Integrating AI has the potential to enable advanced applications in robotics, healthcare, and human-machine interfaces but also presents challenges such as data diversity and AI model robustness. In this review, we first summarize the functions and features of e-skins, followed by feature extraction of sensory data and different AI models. Next, we discuss the utilization of AI in the design of e-skin sensors and address the key topic of AI implementation in data processing and analysis of e-skins to accomplish a range of different tasks. Subsequently, we explore hardware-layer in-skin intelligence before concluding with an analysis of the challenges and opportunities in the various aspects of AI-enabled e-skins.

Ambient energy harvesters in wearable electronics: fundamentals, methodologies, and applications

In recent years, wearable sensor devices with exceptional portability and the ability to continuously monitor physiological signals in real time have played increasingly prominent roles in the fields of disease diagnosis and health management. This transformation has been largely facilitated by materials science and micro/nano-processing technologies. However, as this technology continues to evolve, the demand for multifunctionality and flexibility in wearable devices has become increasingly urgent, thereby highlighting the problem of stable and sustainable miniaturized power supplies. Here, we comprehensively review the current mainstream energy technologies for powering wearable sensors, including batteries, supercapacitors, solar cells, biofuel cells, thermoelectric generators, radio frequency energy harvesters, and kinetic energy harvesters, as well as hybrid power systems that integrate multiple energy conversion modes. In addition, we consider the energy conversion mechanisms, fundamental characteristics, and typical application cases of these energy sources across various fields. In particular, we focus on the crucial roles of different materials, such as nanomaterials and nano-processing techniques, for enhancing the performance of devices. Finally, the challenges that affect power supplies for wearable electronic products and their future developmental trends are discussed in order to provide valuable references and insights for researchers in related fields.

Flexible self-powered bioelectronics enables personalized health management from diagnosis to therapy

Flexible self-powered bioelectronics (FSPBs), incorporating flexible electronic features in biomedical applications, have revolutionized the human-machine interface since they hold the potential to offer natural and seamless human interactions while overcoming the limitations of battery-dependent power sources. Furthermore, as biosensors or actuators, FSPBs can dynamically monitor physiological signals to reveal real-time health abnormalities and provide timely and precise treatments. Therefore, FSPBs are increasingly shaping the landscape of health monitoring and disease treatment, weaving a sophisticated and personalized bond between humans and health management. Here, we examine the recent advanced progress of FSPBs in developing working mechanisms, design strategies, and structural configurations toward personalized health management, emphasizing its role in clinical medical scenarios from biophysical/biochemical sensors for sensing diagnosis to robust/biodegradable actuators for intervention therapy. Future perspectives on the challenges and opportunities in emerging multifunctional FSPBs for the next-generation health management systems are also forecasted.

Multi-Layer PVA-PANI Conductive Hydrogel for Symmetrical Supercapacitors: Preparation and Characterization

This work describes a simple, inexpensive, and robust method to prepare a flexible "all in one" integrated hydrogel supercapacitors (HySCs). Preparing smart hydrogels with high electrical conductivity, ability to stretch significantly, and excellent mechanical properties is the last challenge for tailored wearable devices. In this paper, we employed a physical crosslinking process that involves consecutive freezing and thawing cycles to prepare a polyvinyl alcohol (PVA)-based hydrogel. Exploiting the self-healing properties of these materials, the assembly of the different layers of the HySCs has been performed. The ionic conductivity within the electrolyte layer arises from the inclusion of an H2SO4 solution in the hydrogel network. Instead, the electronic conductivity is facilitated by the addition of the conductive polymer PANI-PAMPSA into the hydrogel layers. Electrochemical measures have highlighted newsworthy properties related to our HySCs, opening their use in wearable electronic applications.

High Sensitivity Triboelectric Based Flexible Self-Powered Tactile Sensor with Bionic Fingerprint Ring Structure

Flexible self-powered tactile sensors, with applications spanning wearable electronics, human-machine interaction, prosthetics, and soft robotics, offer real-time feedback on tactile interactions in diverse environments. Despite advances in their structural development, challenges persist in sensitivity and robustness, particularly when additional functionalities, such as high transparency and stretchability. In this study, we present a novel approach integrating a bionic fingerprint ring structure with a PVDF-HFP/AgNWs composite fiber electrode membrane, fabricated via 3D printing technology and electrospinning, respectively, yielding a triboelectric nanogenerator (TENG)-based self-powered tactile sensor. The sensor demonstrates high sensitivity (5.84 V/kPa in the 0-10 kPa range) and rapid response time (10 ms), attributed to the microring texture on its surface, and exhibits exceptional robustness, maintaining electrical output integrity even after 24,000 cycles of loading. These findings highlight the potential of the microring structures in addressing critical challenges in flexible sensor technology.

Phase-Directed Assembly of Triboelectric Nanopaper for Self-Powered Noncontact Sensing

Noncontact sensing technology serves as a pivotal medium for seamless data acquisition and intelligent perception in the era of the Internet of Things (IoT), bringing innovative interactive experiences to wearable human-machine interaction perception networks. However, the pervasive limitations of current noncontact sensing devices posed by harsh environmental conditions hinder the precision and stability of signals. In this study, the triboelectric nanopaper prepared by a phase-directed assembly strategy is presented, which possesses low charge transfer mobility (1618 cm2 V-1 s-1) and exceptional high-temperature stability. Wearable self-powered noncontact sensors constructed from triboelectric nanopaper operate stably under high temperatures (200 °C). Furthermore, a temperature warning system for workers in hazardous environments is demonstrated, capable of nonintrusively identifying harmful thermal stimuli and detecting motion status. This research not only establishes a technological foundation for accurate and stable noncontact sensing under high temperatures but also promotes the sustainable intelligent development of wearable IoT devices under extreme environments.

A Study on the Mechanism and Properties of a Self-Powered H2O2 Electrochemical Sensor Based on a Fuel Cell Configuration with FePc and Graphene Cathode Catalyst Materials

Conventional electrochemical sensors use voltammetric and amperometric methods with external power supply and modulation systems, which hinder the flexibility and application of the sensors. To avoid the use of an external power system and to minimize the number of electrochemical cell components, a self-powered electrochemical sensor (SPES) for hydrogen peroxide was investigated here. Iron phthalocyanine, an enzyme mimetic material, and Ni were used as a cathode catalyst and an anode material, respectively. The properties of the iron phthalocyanine catalyst modified by graphene nanoplatelets (GNPs) were investigated. Open circuit potential tests demonstrated the feasibility of this system. The GNP-modulated interface helped to solve the problems of aggregation and poor conductivity of iron phthalocyanine and allowed for the achievement of the best analytical characteristics of the self-powered H2O2 sensor with a low detection limit of 0.6 µM and significantly higher sensitivity of 0.198 A/(M·cm2) due to the enhanced electrochemical properties. The SPES demonstrated the best performance at pH 3.0 compared to pH 7.4 and 12.0. The sensor characteristics under the control of external variable load resistances are discussed and the cell showed the highest power density of 65.9 μW/cm2 with a 20 kOhm resistor. The practical applicability of this method was verified by the determination of H2O2 in blood serum.

Low hysteresis zwitterionic supramolecular polymer ion-conductive elastomers with anti-freezing properties, high stretchability, and self-adhesion for flexible electronic devices

The fabrication of stretchable ionic conductors with low hysteresis and anti-freezing properties to enhance the durability and reliability of flexible electronics even at low temperatures remains an unmet challenge. Here, we report a facile strategy to fabricate low hysteresis, high stretchability, self-adhesion and anti-freezing zwitterionic supramolecular polymer ion-conductive elastomers (ICEs) by photoinitiated polymerization of aqueous precursor solutions containing a newly designed zwitterionic monomer carboxybetaine ureido acrylate (CBUIA) followed by solvent evaporation. The resultant poly(carboxybetaine ureido acrylate) (PCBUIA) ICEs are highly stretchable and self-adhesive owing to the presence of strong hydrogen bonds between ureido groups and dipole-dipole interactions of zwitterions. The zwitterion groups on the polymer side chains and loaded-lithium chloride endow PCBUIA ICEs with excellent anti-freezing properties, demonstrating mechanical flexibility and ionic transport properties even at a low temperature (-20 °C). Remarkably, the PCBUIA ICEs demonstrate a low hysteresis (≈10%) during cyclic mechanical loading-unloading (≤500%), and are successfully applied as wearable strain sensors and triboelectric nanogenerators (TENGs) for energy harvesting and human motion monitoring. In addition, the PCBUIA ICE-based TENG was used as a wireless sensing terminal for Internet of Things smart devices to enable wireless sensing of finger motion state detection.