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Abstract Laser‐induced graphene (LIG) technology has provided a new manufacturing strategy for the rapid and scalable assembling of triboelectric nanogenerators (TENG). However, current LIG‐based TENG commonly rely on polymer films, e.g., polyimide (PI) as both friction material and carbon precursor of electrodes, which limit the structural diversity and performance escalation due to its incapability of folding and creasing. Using specialized PI paper composed of randomly distributed PI fibers to substantially enhance its foldability, this work creates a new type of TENG, which are structurally foldable and stackable, and performance tailorable. First, by systematically investigating the laser power‐regulated performance of single‐unit TENG, the open‐circuit voltage can be effectively improved. By further exploiting the folding process, multiple TENG units can be assembled together to form multi‐layered structures to continuously expand the open‐circuit voltage from 5.3 to 34.4 V cm−2, as the increase of friction units from 1 to 16. Last, by fully utilizing the unique structure and performance, representative energy‐harvesting and smart‐sensing applications are demonstrated, including a smart shoe to recognize running motions and power LEDs, a smart leaf to power a thermometer by wind, a matrix sensor to recognize writing trajectories, as well as a smart glove to recognize different objects.

Green and sustainable power sources for next-generation electronics are being developed. A cellulose paper-based triboelectric nanogenerator (TENG) was fabricated to harness mechanical energy and convert it into electricity. This work proposes a novel approach to modify cellulose paper with natural dyes, including chlorophyll from spinach, anthocyanin from red cabbage, and curcumin from turmeric, to enhance the power output of a TENG. All the natural dyes are found to effectively improve the energy conversion performance of a cellulose paper-based TENG due to their photogenerated charges. The highest power density of 3.3 W/m2 is achieved from the cellulose paper-based TENG modified with chlorophyll, which is higher than those modified with anthocyanin and curcumin, respectively. The superior performance is attributed not only to the photosensitizer properties but also the molecular structure of the dye that promotes the electron-donating properties of cellulose.

Developers of electronics for the Internet of Things are considering nonstandard substrate materials like recyclable, low-cost, and eco-friendly cardboard paper. From this perspective, this article reviews the design and experimental results of a 2D-rectenna for scavenging radio-frequency energy at 2.45 GHz on various cardboard paper substrates for both the antenna and rectifier. Four types of recycled cardboard material, each with different thicknesses, air gaps, and surface roughness, are selected for characterization. A linearly polarized rectangular microstrip patch antenna with microstrip transmission feeding is adopted for ease of fabrication. At 2.45 GHz, the antenna has a simulated and measured global gain of 2.98 dB and 2.53 dB, respectively, on a 2.2 mm thick cardboard material. The rectifying element consists of a voltage-doubler configuration connected through a T-matching network to the antenna. At low RF input power (−10 dBm), the maximum available DC output power is experimentally evaluated at 1.73 μW, 7.5 μW, and 8.5 μW for HSMS-2860, HSMS-2850, and SMS7306-079L diodes, respectively. The respective rectifiers with diodes SMS7306-079L, HSMS-2850, and HSMS-2860 exhibit optimal load values of 2 kΩ, 2.6 kΩ, and 8 kΩ. The rectifier designed using the SMS7306-079L diode experimentally reaches a maximum power conversion efficiency (PCE) of 14.2% at −5 dBm input power when the optimal load value is 1.5 kΩ. [ABSTRACT FROM AUTHOR]

Laser‐induced graphene (LIG) technology has provided a new manufacturing strategy for the rapid and scalable assembling of triboelectric nanogenerators (TENG). However, current LIG‐based TENG commonly rely on polymer films, e.g., polyimide (PI) as both friction material and carbon precursor of electrodes, which limit the structural diversity and performance escalation due to its incapability of folding and creasing. Using specialized PI paper composed of randomly distributed PI fibers to substantially enhance its foldability, this work creates a new type of TENG, which are structurally foldable and stackable, and performance tailorable. First, by systematically investigating the laser power‐regulated performance of single‐unit TENG, the open‐circuit voltage can be effectively improved. By further exploiting the folding process, multiple TENG units can be assembled together to form multi‐layered structures to continuously expand the open‐circuit voltage from 5.3 to 34.4 V cm−2, as the increase of friction units from 1 to 16. Last, by fully utilizing the unique structure and performance, representative energy‐harvesting and smart‐sensing applications are demonstrated, including a smart shoe to recognize running motions and power LEDs, a smart leaf to power a thermometer by wind, a matrix sensor to recognize writing trajectories, as well as a smart glove to recognize different objects. [ABSTRACT FROM AUTHOR]

A thermoelectric generator (TEG) is one of the important energy harvesting sources for wearable electronic devices, which converts waste heat into electrical energy without any external stimuli, such as light or mechanical motion. However, the poor flexibility of traditional TEGs (e.g., Si-based TE devices) causes the limitations in practical applications. Flexible paper substrates are becoming increasingly attractive in wearable electronic technology owing to their usability, environmental friendliness (disposable, biodegradable, and renewable materials), and foldability. The high water-absorbing quality of paper restricts its scope of application due to water failure. Therefore, we propose a high-performance flexible waterproof paper-based thermoelectric generator (WPTEG). A modification method that infiltrates TE materials into cellulose paper through vacuum filtration is used to prepare the TE modules. By connecting the TE-modified paper with Al tape, as well as a superhydrophobic layer encapsulation, the WPTEG is fabricated. The WPTEG with three P–N modules can generate an output voltage of up to 235 mV at a temperature difference of 50 K, which can provide power to portable electronic devices such as diodes, clocks, and calculators in hot water. With the waterproof property, the WPTEG paves the way for achieving multi-scenario applications in humid environments on human skin. [ABSTRACT FROM AUTHOR]

Green and sustainable power sources for next-generation electronics are being developed. A cellulose paper-based triboelectric nanogenerator (TENG) was fabricated to harness mechanical energy and convert it into electricity. This work proposes a novel approach to modify cellulose paper with natural dyes, including chlorophyll from spinach, anthocyanin from red cabbage, and curcumin from turmeric, to enhance the power output of a TENG. All the natural dyes are found to effectively improve the energy conversion performance of a cellulose paper-based TENG due to their photogenerated charges. The highest power density of 3.3 W/m2 is achieved from the cellulose paper-based TENG modified with chlorophyll, which is higher than those modified with anthocyanin and curcumin, respectively. The superior performance is attributed not only to the photosensitizer properties but also the molecular structure of the dye that promotes the electron-donating properties of cellulose. [ABSTRACT FROM AUTHOR]

The development of industry and of the Internet of Things (IoTs) have brought energy issues and huge challenges to the environment. The emergence of triboelectric nanogenerators (TENGs) has attracted wide attention due to their advantages, such as self-powering, lightweight, and facile fabrication. Similarly to paper and other fiber-based materials, which are biocompatible, biodegradable, environmentally friendly, and are everywhere in daily life, paper-based TENGs (P-TENGs) have shown great potential for various energy harvesting and interactive applications. Here, a detailed summary of P-TENGs with two-dimensional patterns and three-dimensional structures is reported. P-TENGs have the potential to be used in many practical applications, including self-powered sensing devices, human–machine interaction, electrochemistry, and highly efficient energy harvesting devices. This leads to a simple yet effective way for the next generation of energy devices and paper electronics.

Recently, as the use of wearable devices and the demand for eco-friendly energy have increased, many studies have been conducted on triboelectric nanogenerators (TENGs), which can economically harvest energy. Paper is considered a promising substrate and frame material that can be used to manufacture self-powered TENGs, owing to its flexibility, low cost, and accessibility. Herein, we present a sandwich-structured foldable paper-based TENG (FP-TENG) that comprises flexible materials and uses paper as a substrate. The FP-TENG can generate up to 572 mW/m2 of power via contact–separation of the triboelectric electrified body at the top and bottom. With more folds of the FP-TENG, the triboelectric cross-sectional area increases, and, thus, the electrical output increases. In addition, the proposed TENG exhibits excellent durability without signal degradation under 5000 cycles of repeated pushing motions. To demonstrate its practicality, the FP-TENG was manufactured in the form of a wristwatch Velcro and connected to an electronic watch panel to supply power. Various deformations are possible with origami, and they can drive wristwatches through external forces. Therefore, the FP-TENG is expected to be utilized as a sustainable and promising eco-friendly energy source for small electronic devices.

The research presented in this paper introduces a novel environmental energy‐harvesting technology that harnesses electricity from the evaporation of water using porous structural materials. Specifically, a strategy employing paper‐based hydroelectric generators (p‐HEGs) is proposed to capture the energy produced during water evaporation and convert it into usable electricity. The p‐HEGs offer several advantages, including simplicity in fabrication, low cost, and reusability. To evaluate their effectiveness, the water evaporation‐induced electrical output performance of four different p‐HEGs are compared. Among the variants tested, the p‐HEG combining wood pulp and polyester fiber exhibits the best output performance. At room temperature, this particular p‐HEG generates a short‐circuit current and open‐circuit voltage of ≈0.4 µA and 0.3 V, respectively, thereby demonstrating excellent electrical stability. Furthermore, the electrical current and voltage generated by the p‐HEG through water evaporation are able to power an LED light, both individually and in series and parallel connections. This study delves into the potential of electricity harvesting from water evaporation and establishes it as a viable method for renewable energy applications. [ABSTRACT FROM AUTHOR]

An intelligent reflecting surface (IRS) is proposed to enhance the physical layer security in the Rician fading channel wherein the angular direction of the eavesdropper (ED) is aligned with a legitimate user. A two-phase communication system under active attacks and passive eavesdropping is considered in this scenario. The base station avoids direct transmission to the attacked user in the first phase, whereas other users cooperate in forwarding signals to the attacked user in the second phase, with the help of IRS and energy harvesting technology. Under the occurrence of active attacks, an outage-constrained beamforming design problem is investigated under the statistical cascaded channel error model, which is solved by using the Bernstein-type inequality. An average secrecy rate maximization problem for the passive eavesdropping is formulated, which is then addressed by a low-complexity algorithm. The numerical results of this study reveal that the negative effect of the ED’s channel error is larger than that of the legitimate user.

Recently, as the use of wearable devices and the demand for eco-friendly energy have increased, many studies have been conducted on triboelectric nanogenerators (TENGs), which can economically harvest energy. Paper is considered a promising substrate and frame material that can be used to manufacture self-powered TENGs, owing to its flexibility, low cost, and accessibility. Herein, we present a sandwich-structured foldable paper-based TENG (FP-TENG) that comprises flexible materials and uses paper as a substrate. The FP-TENG can generate up to 572 mW/m2 of power via contact–separation of the triboelectric electrified body at the top and bottom. With more folds of the FP-TENG, the triboelectric cross-sectional area increases, and, thus, the electrical output increases. In addition, the proposed TENG exhibits excellent durability without signal degradation under 5000 cycles of repeated pushing motions. To demonstrate its practicality, the FP-TENG was manufactured in the form of a wristwatch Velcro and connected to an electronic watch panel to supply power. Various deformations are possible with origami, and they can drive wristwatches through external forces. Therefore, the FP-TENG is expected to be utilized as a sustainable and promising eco-friendly energy source for small electronic devices. [ABSTRACT FROM AUTHOR]

• Hydroxyapatite (HAP) composite paper with biocompatibility and hygroscopicity was prepared. • HAP composite paper has better hygroscopic and triboelectric properties than pure paper, making it more suitable for wearable sensing applications. • The HAP composite paper-based triboelectric nanogenerator can detect and distinguish different joint movements. • Hemostatic and disposable HAP composite paper can be degraded in the natural environment without harm. Wearable triboelectric nanogenerators (TENGs) have attracted considerable attention in the field of self-powered sensors that can be worn on the skin directly without packaging because of their breathability, conformability, and sensitivity to collect biomechanical energy. However, high humidity on the skin can affect the wearable TENG output performance, substantially affecting the sensor performance and stability. When worn for a long time, humidity can even cause skin inflammation. Thus, for a wearable TENG, moisture control and biocompatibility are also key factors that need to be addressed. Herein, we report a hygroscopic and biocompatible paper-based TENG using a hydroxyapatite (HAP) mineral coating to enhance the paper fiber. The mineral coating can maintain the surface of the paper fiber, which will not cause large external deformation of the paper fiber under a force, avoid squeezing out excess water, and keep the friction surface dry, avoiding humidity affecting the output performance. Without interfering with the performance of the TENG, the maximum water absorption of the HAP composite paper is ∼8 μL. The HAP composite paper–based TENG (4 cm2) has an open-circuit voltage and short-circuit current 5.8 times and 4.2 times that of pure paper, respectively, and can obtain 80.4 mW/m2 output and directly light 117 LEDs. At relative humidity values of 25.7 %, 43.1 %, and 58.8 %, the performance retained the peak values of 80.2 %, 68 %, and 63.7 %, respectively. Even at a high relative humidity of 71.7 %, the triboelectric performance of HAP composite paper is retained 59.3 %, and the stability under humidity is better than that of pure paper (45.6 %). In addition, the mineral paper can even work with tissue fluid and output performance decreases by 43.8 %. The mineral-enhanced paper TENG with high power generation performance, hygroscopicity, biocompatibility, and degradability provides a new perspective for disposable wearable sensors, even in medical treatment. [ABSTRACT FROM AUTHOR]

Microbial fuel cell is a promising technology to harvest energy from wastewater, and effective anode catalysts are essential for its applications. In this study, zero-dimension nitrogen-doped carbon dots, as biocompatible efficient modifiers, were synthesized and decorated onto the carbon paper surface to prepare microbial fuel cell anode. The as-fabricated nitrogen-doped carbon dots decorated carbon paper anode was able to enhance electricity generation and efficient wastewater treatment. It was found that the as-fabricated electrode had a high hydrophilicity, which was favorable for the microbial immobilization. Compared with the carbon paper anode, the biofilm on the as-prepared anode was almost twice of thickness. After introducing nitrogen-doped carbon dots, the extracellular electron transfer process from the microorganisms to the anode was enhanced. The microbial fuel cell with the as-developed anode generated a remarkable power output of 0.32 mW, 1.1 times higher than that of the raw carbon paper anode with same measurement area. Moreover, 16 sRNA pyrosequencing analysis shows that the quantity of Pseudomonas on the electrode increased by ∼40%, which also promoted the electron transfer rate by excreting mediators like phenazines or phenazine derivatives. This work developed a new approach to design microbial fuel cell anode material and fabricate a high-efficiency and environmentally friendly anode for electricity generation from wastewater. Image 100697 • Notable power output was obtained from MFC with N-doped CDs@carbon paper electrode. • The carbon paper electrode was highly hydrophilic by decorating with N-doped CDs. • The EET efficiency was enhanced by modifying the electrode with N-doped CDs. • The relative abundance of Pseudomonas was enhanced with N-doped CDs' decoration. [ABSTRACT FROM AUTHOR]

We report on the fabrication of zinc oxide (ZnO) nanorod-based flexible, cost-effective single electrode triboelectric nanogenerator (STENG) on cellulose paper platform. In particular, the influence of surface functional groups of ZnO nanorods on the STENG output has been investigated. The STENG has been designed with chemically grown ZnO nanorod-coated paper as active triboelectric layer and Teflon/ Aluminum as counter triboelectric layer/ electrode. It has been found that post-annealing of nanorods at 125∘C improves the output voltage by twice compared to the pristine nanorods and delivers an output power of ∼ 0. 2 μ W/cm2. With annealing up to 125∘C, the optimal removal of the chemisorbed water from the defect sites of ZnO surface increases the intrinsic carrier concentration leading to maximum charge transfer and hence higher triboelectric output. On the other hand, a higher extent of oxygen accumulation from air at 150∘C lowers the intrinsic carrier concentration resulting in the reduced output. It has been proposed that the competition between the events like water removal and oxygen accumulation under different annealing temperatures can influence the STENG output largely. Finally, the optimized STENG has been demonstrated to work as wearable bio-mechanical sensors operating through bio-mechanical stimuli. [ABSTRACT FROM AUTHOR]

Nanogenerators possess the capability to harvest faint energy from the environment. Among them, thermoelectric (TE), triboelectric, piezoelectric (PE), and moisture-enabled nanogenerators represent promising approaches to micro–nano energy collection. These nanogenerators have seen considerable progress in material optimization and structural design. Printing technology has facilitated the large-scale manufacturing of nanogenerators. Although inks can be compatible with most traditional functional materials, this inevitably leads to a decrease in the electrical performance of the materials, necessitating control over the rheological properties of the inks. Furthermore, printing technology offers increased structural design flexibility. This review provides a comprehensive framework for ink-based nanogenerators, encompassing ink material optimization and device structural design, including improvements in ink performance, control of rheological properties, and efficient energy harvesting structures. Additionally, it highlights ink-based nanogenerators that incorporate textile technology and hybrid energy technologies, reviewing their latest advancements in energy collection and self-powered sensing. The discussion also addresses the main challenges faced and future directions for development. [ABSTRACT FROM AUTHOR]

Recently, triboelectric nanogenerators (TENGs) have proven to be promising energy harvesters, but they can also play the role of self-powered human motion sensors. Thus, we design a TENG device based on chitosan-cotton-paper (CCP-TENG) to harvest mechanical energy and serve as a self-powered sensor. The chitosan-cotton-paper (CCP) film and PTFE were used as the triboelectric materials, and aluminum foil served as the conductive electrode. According to results, the CCP-TENG can realize an open-circuit voltage (Voc) of 162 V and a short-circuit current (Isc) of 7.2 μA. Meanwhile, the maximum output power density of the CCP-TENG can reach 322.56 mW/m2 with a match load of 20 MΩ. In addition, the CCP-TENG can be used as a self-powered grip force sensor, which has important application value in human health monitoring. This study suggests a simple, environmentally friendly way to make TENGs for biomechanical energy generating and tracking human movement. [ABSTRACT FROM AUTHOR]

This comprehensive review explores recent advancements in the manufacturing of cellulose nanofiber (CNF)-based cellulose nanopaper (CNP). The analysis delves into customizing CNPs through nanofiber manufacturing, mechanical refining, and chemical treatments. The report underscores the growing interest in CNPs derived from CNF due to their exceptional properties and eco-friendly attributes. CNP strength significantly enhanced through mechanical refining encompassing cellulose nanofibrillation were breaking down of cellulose into nanofibers takes place. Conversely, dense CNF network formed through filtration and casting method. Chemical treatments such as dispersion, functionalization, and coating methods followed by drying and consolidation introduce custom functionalities for diverse applications. These applications span packaging, electronics, energy harvesting, EMI shielding, optoelectronics, nanogenerators, transparent conducting films, water treatment, bioelectronics, and neuromorphic computing. The study conducts an in-depth investigation to assess CNP's effects on promoting sustainability and minimizing environmental waste, making a significant contribution to the circular economy. This investigation underscores the pursuit of innovation and aligns with the principles of progressing toward a more environmentally sustainable future. [Display omitted] • Explores CNF production, refining and chemical treatments for CNP customization. • Remarkable properties of CNP draw academic and industrial interest. • CNP applied in packaging, electronics, energy, and environmental science. • Investigates role of CNP in circular economy. • Emphasizes CNPs as eco-friendly, fostering innovation and sustainability. [ABSTRACT FROM AUTHOR]

Osmotic energy harvesting was a promising way to alleviate energy crisis with reverse electrodialysis (RED) membrane-based technology. Charged hydrogel combined with other materials was an effective strategy to overcome problems, including restricted functional groups and complicated fabrication, but the effect of the respective charges of the two materials combined on the membrane properties has rarely been studied in depth. Herein, a new method was proposed that charged hydrogel was equipped with charged filter paper to form dual network fiber-hydrogel membrane for osmotic energy harvesting, which had excellent ion selectivity (beyond 0.9 under high concentration gradient), high ion transference number and energy conversion efficiency (beyond 32.5% under wide range concentration gradient), good property of osmotic energy conversion (~4.84 W/m2 under 50-fold KCl and ~6.75 W/m2 under simulated sea water and river water). Moreover, the power density was attributed to the surface-space charge synergistic effect from large amounts overlapping of electric double layer (EDL), so that the transmembrane ion transport was enhanced. It might be a valid mode to extensively develop the osmotic energy harvesting. [ABSTRACT FROM AUTHOR]

Here, we propose a microfluidic paper-based analytical device (µPAD) implemented with a near-field communication (NFC) tag as a portable, simple and fast colorimetric method for glutathione (GSH) determination. The proposed method was based on the fact that Ag+ could oxidize 3,3′,5,5′-tetramethylbenzidine (TMB) into oxidized blue TMB. Thus, the presence of GSH could cause the reduction of oxidized TMB, which resulted in a blue color fading. Based on this finding, we developed a method for the colorimetric determination of GSH using a smartphone. A µPAD implemented with the NFC tag allowed the harvesting of energy from a smartphone to activate the LED that allows the capture of a photograph of the µPAD by the smartphone. The integration between electronic interfaces into the hardware of digital image capture served as a means for quantitation. Importantly, this new method shows a low detection limit of 1.0 µM. Therefore, the most important features of this non-enzymatic method are high sensitivity and a simple, fast, portable and low-cost determination of GSH in just 20 min using a colorimetric signal. [ABSTRACT FROM AUTHOR]

With the rapid proliferation of portable and wearable electronics, energy autonomy through efficient energy harvesting has become paramount. Thermoelectric generators (TEGs) stand out as promising candidates due to their silent operation, high reliability, and maintenance-free nature. This paper presents the design, fabrication, and analysis of a micro-scale TEG for powering such devices. A planar configuration was employed for its inherent miniaturization advantages. Finite element analysis using ANSYS reveals that a double-layer device under a 50 K temperature gradient generates an impressive open-circuit voltage of 1417 mV and a power output of 2.4 μW, significantly exceeding its single-layer counterpart (226 mV, 0.12 μW). Validation against the analytical model results yields errors within 2.44% and 2.03% for voltage and power, respectively. Furthermore, a single-layer prototype fabricated using paper shadow masks and sputtering deposition exhibits a voltage of 131 mV for a 50 K temperature difference, thus confirming the feasibility of the proposed design. This work establishes a foundation for developing highly efficient micro-TEGs for powering next-generation portable and wearable electronics. [ABSTRACT FROM AUTHOR]

Billions of costless near‐field communication (NFC) sensor labels per day are demanded to practically enable edge computing between smartphones and everyday objects. However, to activate the billions of NFC sensor labels daily, providing an inexpensive manufacturing method for billions of wireless energy‐harvesting labels (WeHL) per day will become a decisive issue for realizing the practical applications. Herein, a roll‐to‐roll (R2R) gravure, a typical high‐throughput additive manufacturing method, is explored to print WeHLs where six diodes and six capacitors are integrated. To meet the high‐throughput manufacturing speed (90 mm s−1) of the R2R gravure system, six different electronic inks are formulated to print the WeHLs to harvest ±10 V from the smartphone's NFC carrier. To attain a practical device yield under the given printing speed, the web tension, nip force, doctor blade angle, and overlay printing registration accuracy are well controlled and optimized to print six different layers within a high overlay printing accuracy, while printing patterns to connect two electrodes with a height difference greater than 3 μm. The fully R2R‐printed WeHLs can successfully harvest energy from the smartphone's NFC carrier with the conversion efficiency of 50%. [ABSTRACT FROM AUTHOR]

A paper-based multi-anode microbial fuel cell (PMMFC) integrated with power management system (PMS) was developed as a disposable self-support real-time “shock” biosensor for wastewater. PMMFCs were examined at three types of shocks (chromium, hypochlorite and acetate) in a batch-mode chamber, and exhibited various responses to shock types and concentrations. The power output of PMMFC sensor was four times as the carbon cloth (CC)-based MFCs, indicating the advantage of paper-based anode for bacterial adhesion. The power output was more sensitive than the voltage output under shocks, and thus preventing the false signals. The simulation of power harvest using PMS indicated that PMMFC could accomplish more frequent data transmission than single-anode MFCs (PSMFC) and CC anode MFCs (CCMMFC), making the self-support wastewater monitor and data transmission possible. Compared with traditional MFC sensors, PMMFCs integrated with PMS exhibit the distinct advantages of tight paper-packed structure, short acclimation period, high power output, and high sensitivity to a wide range of shocks, posing a great potential as “disposable self-support shock sensor” for real time in situ monitoring of wastewater quality. [ABSTRACT FROM AUTHOR]

This paper presents a shock detection device for packages in the supply chain. The primary purpose is to identify package damage during storage, delivery, and handling. Additionally, products are likely to be damaged if dropped from a certain height, which sometimes does not appear on the package. By continuously measuring package vibrations and detecting shocks in the supply chain, consumers can gain an insight into the state of the product upon delivery. This paper presents the Smart Sticker implementation for ultra-low-power shock detection in the supply chain. The overall energy consumption must be kept as low as possible while continuously sensing the presence of shock to ensure that the Smart Sticker's battery lasts as long as possible. The Smart Sticker functions in three modes to meet the established constraints: low-power, active, and data transfer mode. While detecting the shock, the low-power mode uses the least amount of energy needed. If the shock exceeds the threshold, the Smart Sticker enters active mode, stores the detected g force value in memory, and then switches back to low-power mode. Finally, employing Near Field Communication (NFC) and energy harvesting, the data transfer mode allows the consumer to read the recorded data. The results show that the Smart Sticker for shock detection performs according to set requirements and successfully monitors and detects shock for packages in the supply chain. [ABSTRACT FROM AUTHOR]

This paper introduces a novel compact ultralightweight multiband RF energy harvester fabricated on a paper substrate. The proposed rectenna is designed to operate in all recently released LTE bands (range 0.79–0.96 GHz; 1.71–2.17 GHz; and 2.5–2.69 GHz). High compactness and ease of integration between antenna and rectifier are achieved by using a topology of nested annular slots. The proposed rectifier features an RF-to-dc conversion efficiency in the range of 5%–16% for an available input power of −20 dBm in all bands of interest, which increases up to 11%–30% at −15 dBm. The rectenna has been finally tested both in laboratory and in realistic scenarios featuring a superior performance to other state-of-the-art RF harvesters on flexible substrates. [ABSTRACT FROM PUBLISHER]

The printable paper-based enzymatic biofuel cell (PBFC) to directly power small devices is an important objective for realizing cost-effective and disposable energy harvesting devices. In the present study, a screen-printed circular-type PBFC, composed of a series of 5 individual cells, was constructed. The PBFC exhibited the open circuit potential of 2.65 V and maximum power of 350 μW at 1.55 V, which were sufficient to illuminate an LED without requiring a booster circuit. The output voltage of this PBFC can also be easily adjusted as required. [ABSTRACT FROM AUTHOR]

Today's wearable electronics have dramatically altered our daily lives and created an urgent demand for new and intelligent sensor technologies. As a new energy source, self-powering sensors are currently seen as critically important units for wearable and non-wearable textile–electronic systems. To this aim, this paper presents a smart textile-based piezoelectric energy-autonomous harvester and a self-powered sensor for wearable application, where the sandwich structure of the wearable sensor consists of top and bottom textile conductors, and in between the two textile electrodes there is a piezoelectric PVDF thin film. The generating voltage, current, charge, power, and capacitor charging–discharging behaviour of the device were confirmed using multimeter, oscilloscope, Keithley, etc., analyses. Finally, a piezoelectric-textile sensor was integrated into wearable clothes for breathing detection; a shoe insole for footstep recognition; and it can store energy by tapping, to power electronics, such as a calculator, timer, LED, etc., at a later time. The sensitivity of the sensor was enough for generating voltage from a tiny water droplet. Thus, we can assume raindrops to be utilized as a power-generating source on days when no sun is available to solar cells. [ABSTRACT FROM AUTHOR]

The text is an editorial from the Journal of Materials Science discussing a cover paper titled "High-performance, water-resistant and ion-conducting gel used as underwater ECG electrodes" by Shi et al. The paper addresses the challenges of sensing underwater and describes the synthesis and characterization of a single-layer hydrogel electrode that is resistant to swelling in water. The paper is accessible to non-experts and includes photographs, curves, and electrocardiograms to support the findings. Although the article is not open access, it can be accessed through a SharedIt link provided by the publisher. [Extracted from the article]