Low-power Electronic Devices Research Articles

Energy Harvesting System with Solar Panels to Supply Low Power Electronic Devices

Solar panels allow acquiring energy from the environment which can be stored for Energy Harvesting purposes. The objective of this work is to design, simulate and characterize different configurations in the harvesting stage, constituted by solar panels for energy harvesting systems of low consumption, identifying the most adequate arrangement to achieve the highest amount of energy together with the conversion stage. The methodology used has been design, simulation in Matlab-Simulink software and characterization with mini solar panels. The developed system consists of 3 stages which are: energy harvesting, DC-DC converter, and storage, focusing on the Energy Harvesting stage. The results obtained in simulation of 4.8V and 160 mA, and measurement of 4.60V and 134.5mA show that the mixed configuration is the one that presents better results in both voltage and current, concluding that the simulated and measured values are very close obtaining an error of 0.05% and 0.16% in voltage and current respectively and an output voltage of the converter of up to 26V. Finally, these results are very promising for Energy Harvesting applications.

Raman spectroscopic study of the layer-dependent Davydov splitting and thermal conductivity of chemically vapor deposited two-dimensional MoSe2

Atomically thin MoSe2 is of interest from the perspective of estimating the layer-dependent material properties necessary for the translation of two-dimensional materials into devices. This work presents Raman spectroscopic protocols to determine a multitude of material parameters of two-dimensional MoSe2 films, including the layer thickness as well as the layer-dependent thermal conductivity, interlayer interactions, and anharmonicity. The Davydov splitting (factor-group splitting) observed in an out-of-plane A1g Raman mode, being layer-dependent in both the number and the peak positions, provides a method for estimating the number of layers. Furthermore, this work demonstrates the determination of the thermal conductivity (K) from the temperature-dependent Davydov split Raman modes of the multi-layers. The measurement of K by conventional methods is otherwise challenging for the micrometer sizes of the two-dimensional materials. The value of K thus determined increases significantly from 9 W m−1 K−1 for a four-layer thick MoSe2 film to 52 W m−1 K−1 for a monolayer. The diminishing effect of anharmonicity observed in the monolayer as compared to multi-layer MoSe2 supports the layer-dependent trend in the thermal conductivity. Overall, the findings are relevant for the applications of 2D MoSe2 in low power electronic, optoelectronic, and thermoelectric devices.

Quantum transport phenomena in magnetic topological insulators

In the past decade, magnetic topological insulators have been an important focus in condensed matter physics research. The intricate interplay between the nontrivial band topology and spin, orbit, charge, and dimensionality degrees of freedom can give rise to abundant exotic topological quantum states and topological phase transitions. Measuring the transport properties of magnetic topological insulators is a crucial approach to exploring their exotic properties, which is of significant scientific importance in deepening our understanding of topological quantum states. Simultaneously, it also holds substantial potential applications in the development of novel low-power electronic devices. In this work, experimental progress of transport researches of magnetic topological insulators is reviewed, including quantum anomalous Hall effect and topological quantum phase transitions in magnetically doped topological insulators, the quantum anomalous Hall phase, axion insulator phase and Chern insulator phase in intrinsic antiferromagnetic topological insulator MnBi<sub>2</sub>Te<sub>4</sub>, as well as the helical phase emerged from the Chern insulator in pulsed high magnetic fields. Finally, this work analyzes the future direction of development in magnetic topological insulators, and the transport phenomena that have not been understood in these systems, offering an insight into and perspectives on the potential breakthroughs to be achieved in this area of research.

Enhancing energy extraction from water microdroplets through synergistic electrokinetic and galvanic effects

An efficient carbon black based water-evaporation generator for raising energy extraction from water droplets and its multiple self-powered applications in low-power electronic devices are reached via synergistic electrokinetic and galvanic effects.

Highly stretchable hydroxyapatite bionanocomposite for high-performance triboelectric nanogenerators.

Renewable energy has been a focus in recent years. Triboelectric nanogenerators (TENGs) have potential for converting mechanical energy into electricity. However, there are restrictions on the use of biological materials and bionanocomposites, such as the high cost and complexity of the synthesis process, poor stability, and inadequate output performance. To overcome the constraints of TENGs, we have turned to hydroxyapatite, a biological substance with great biocompatibility and high mechanical strength that can be manufactured from waste materials. We successfully developed a negative triboelectric bionanocomposite hydroxyapatite (HA) loaded polydimethylsiloxane (PDMS) to harness energy from biomechanical sources such as wearable devices. A TENG (2 × 2 cm2) with a pushing force of 2 N and different amounts of HA in PDMS can produce highly stable output voltage, current, surface charge density, and power density values of 300 V, 22.4 μA, 90.36 μC m-2, and 27.34 W m-2, which are 6, 9, and 10 times higher than those without HA, respectively. These improvements were attributed to the highest observed surface potential of 1512 mV. After 20 000 cycles of contact-separation, the HA/PDMS-TENG shows exceptionally stable performance. Furthermore, adding HA improves the mechanical properties and the stretchability of the bionanocomposite. The HA/PDMS bionanocomposite exhibits remarkable stretchability of more than 290%. Effectively harvesting energy from body movements, the TENG gadget may be used to charge multiple commercial capacitors, drive up to 100 LEDs, and power a low-power electronic device. Self-powered sensing and wearable devices are made possible by the HA/PDMS-TENG, which allows their large-scale preparation and deployment.

Ultralow Subthreshold Swing 2D/2D Heterostructure Tunneling Field-Effect Transistor with Ion-Gel Gate Dielectrics

Two-dimensional (2D) transition-metal dichalcogenide (TMD) semiconductors are promising materials for realizing band-to-band tunneling devices owing to the atomically thin layer and abrupt interface of their heterostructures. In this study, we transferred scalable few-atomic-layer thin films using metal-organic chemical vapor deposition (MOCVD)-grown molybdenum disulfide (MoS2) as an n-channel and CVD-grown molybdenum ditelluride (MoTe2) and tungsten diselenide (WSe2) as p-channels to build van der Waals vertical heterostructures. The heterostructures of intrinsic MoS2 and MoTe2 (or WSe2), each having n-type, ambipolar, or high p-type conductivity, were suitable for tunneling field-effect transistor (TFET) applications. We measured the electrical transport properties of the MoS2/MoTe2 (or WSe2) heterostructures using an ion-gel top gate. The fabricated TFET with MoS2/MoTe2 (or WSe2) heterostructures exhibits a subthreshold swing as low as 9.1 (or 7.5) mV/dec. The negative differential transconductance, negative differential resistance, and temperature-dependent I–V characteristics demonstrate the band-to-band tunneling process. The findings have significant potential for applications in the large-area production of next-generation wearable, stretchable, and flexible low-power electronic devices.

Experimental Research of Symmetrical Airfoil Piezoelectric Energy Harvester Excited by Vortex-Induced Flutter Coupling

In order to solve the problem of self-energy supply of vehicle-mounted micro-sensors, bridge detection and some other low-power electronic devices in their working state, a vortex-induced flutter composite nonlinear piezoelectric energy harvester (VFPEH) with symmetrical airfoils on both sides of a cylindrical bluff body is designed. The VFPEH consists of a cantilever beam, a cylindrical bluff body connected to the free end of the cantilever beam, and two airfoil components symmetrically fixed at both ends of the shaft, which enables coupling between vortex-induced vibration and flutter. The airfoil symmetrically arranged on both sides of the cylindrical bluff body induces the cantilever beam to produce bending and torsional composite vibrations at high wind velocities, realizing energy harvest in the two degrees of freedom motion direction, which can effectively improve the output power of the energy harvester. Based on a wind tunnel experimental platform, the effect of key parameters matching impedance and the diameter of the cylindrical bluff body on the output performance of the VFPEH is investigated, together with the output performance of the classical vortex-induced energy harvester (VEH), the flutter energy harvester (FEH) and the VFPEH. The experimental results show that for the VFPEH under a combination of vortex-induced vibrations and flutter vibrations has a better output performance than the VEH and the FEH when using the same size. The coupling of vortex-induced vibration and flutter can reduce the start-up wind velocity of the VFPEH and expand the wind velocity range of the high output power of the VFPEH. The VFPEH has a better output performance at the cylindrical bluff body diameter of 30 mm and a load resistance of 140 kΩ. When the wind velocity range is 2 m/s–15 m/s, the maximum output power of the VFPEH is 6.47 mW, which is 129.4 times and 24.9 times of the maximum output power of the VEH (0.05 mW) and FEH (0.26 mW), respectively.

An electromagnetic energy harvester for applications in a high-speed rail pavement system

Energy harvesting from ambient environment is one of the effective solutions to supply power for low power electronic devices. There are still some challenges such as poor space utilization and low power density for pavement energy harvesters. In this paper, an electromagnetic energy harvester with the double rockers is proposed to harvest the human footstep energy from high-speed rail pavement environment. Combined with two one-way bearings, the proposed double-rocker structure converts up and down motion of plate into a unidirectional rotation motion of the shaft. As the effect of the inertia flywheel, the velocity attenuation of the shaft of generator is slowed down. The dynamic model of the energy harvester with the engagement and disengagement phase is explored. Moreover, the input force and the angular velocity are simulated under the input of the various sinusoidal displacements and frequencies. The simulation and experimental results show that it can obtain the maximum output power of 466.6 mW under the vibration frequency of 5 Hz and the displacement of 10 mm. Further, the inertia flywheel can enhance the system stability and achieve the improvement of average output power by 49.45 % compared with no flywheel system. A pavement block with four energy harvesters is assembled and the actual field test proves it can obtain the maximum voltage of 54.4 V and the output power of 1.034 W, which proves the proposed electromagnetic energy harvester has great potential to achieve self-powered monitoring system and power for the low power electronic devices in high-speed rail environment.

Three State Output Module and Digital Switch Circuit Based on Threshold Memristor

A memristor is a new electronic device with small volumes and small fluctuations. As a two-terminal device, it is mainly characterized by non-volatility and nanoscale characteristic size. Memristors can also calculate and store at the same time, which has a broad application prospect in logic circuits. Traditional integrated circuit technology has been very mature. And CMOS technology has almost reached the limit of physical size. Compared with traditional circuit components, memristor devices are compatible with CMOS circuits with their fast computing speed, low power consumption, and small layout area. A three-state output module based on a threshold memristor is proposed. The structure includes an inverter, a PMOS tube, two NMOS tubes, and two threshold memristors. Compared with the traditional three-state gate which only uses CMOS technology, the circuit area required by the module is smaller and the overall power consumption is lower, which caters to the development trend of portable and low-power electronic devices. Then the digital switch circuit using this module is introduced, which provides a new idea for the data transmission circuit. The circuit and module are simulated and verified by LTspice software.

Tuning of highly piezoelectric bismuth ferrite/PVDF-copolymer flexible films for efficient energy harvesting performance

BiFeO3 (BFO) is a popular multiferroic material exhibiting robust antiferromagnetic and ferroelectric properties and is a promising candidate for use in sensors and transducers. In this work, BFO piezoceramics were synthesized by a simple hydrothermal method and were incorporated into the copolymers PVDF-TrFE and PVDF-HFP to fabricate flexible nanocomposite films. BFO nanoparticles (NPs) act as nucleating agent inside the polymer matrix, thus improving the overall performance of the piezoelectric film. The phase purity of the synthesized BFO NPs was confirmed by XRD and the β-phase content of the fabricated film was calculated from FTIR analysis. The nanocomposite film PVDF-TrFE/BFO with 6 wt% filler loading (PTB6) showed better piezoelectric performance among others. The intrinsic functional properties of the composite film were evaluated by P-E (polarization-electric field) hysteresis loop test. Further, the nanocomposite film, after corona poling, was used for fabrication of a flexible piezoelectric nanogenerator (PNG). The poled films exhibited better piezoelectric as well as dielectric properties. The fabricated PTB6 based PNG generated a maximum of 18.5 V under a biomechanical finger tapping force. This study suggests that the proposed flexible device is a potential candidate for driving low-power electronic devices.

Low-Frequency Wireless Power Transfer Via Rotating Permanent Magnets

The surging applications of low-power sensors and portable electronic devices require a safe, convenient and low-cost charging method which draws interests of the wireless power transfer research field. Conventional WPT techniques using resonant coupling structures are limited by complexity, safety concerns and hardware costs. Electromechanical wireless power transfer (EWPT) techniques provide a low-cost, easy-to-control and safe wireless charging method via moving magnets; but transmission failures may occur due to the position and orientation misalignments of loads from optimum conditions. This article proposes an EWPT system that is able to charge loads at different tilt angles via a low-frequency rotating magnetic field and a permanent magnet rotor. The magnetic field has a uniform distribution in a space volume over 125 000 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . A custom permanent magnet rotor embedded with six identical cylindrical magnets and an induction coil is employed to capture transmitted power. Theoretical analyses and experimental results are presented to prove the feasibility and output capability of the proposed system. The peak output power achieves 130 mW under a magnetic field strength around 1 mT and the system output maintains stable for loads at different tilt angles. Such EWPT method can be applied as a stable power supply for free-positioned and free-oriented sensors or other low-power devices in an enclosed or semienclosed area.

Effect of annealing temperature on structural, optical, magnetic and electrical properties of CrFeO3 multiferroic nanoparticles: A validation to first-principle calculations

Recently, room-temperature multiferroic materials have attracted great interest as they are suitable for the design of low-power electronic and spintronic devices. In this paper, we have investigated the effect of annealing temperature on the structural, electrical and magnetic properties of CrFeO3 multiferroic nanoparticles prepared by sol-gel auto-combustion method. The structural properties by observing X-ray diffractogram and its thorough Rietveld refinement confirmed the trigonal crystal structure with space group R3̅. The crystallite size calculated from the W-H plot increases from 39.6 nm to 100.5 nm with the increase of annealing temperature. FTIR results confirmed the evolution of ilmenite type ABO3 phase. Electron microscopy images showed increase of grain size due to agglomeration of nanoparticles at higher annealing temperature. EDXA spectra and color mapping demonstrated the elemental purity. Magnetic measurements revealed the antiferromagnetic nature of CrFeO3 multiferroic nanoparticles. Electrical measurements showed the decrease in dielectric constant with the increase in frequency. We have validated the results by running systematically first-principle calculations (Density Functional Theory) on CrFeO3 multiferroic nanoparticles.

Thermoelectric generator based on anisotropic wood aerogel for low-grade heat energy harvesting

• A CNT/PEDOT-decorated thermoelectric network is constructed from wood-based framework. • The anisotropic structure is advantageous to convert low-grade heat energy. • Ordered porous structure and energy filtering effect enhance the TE performance. • Successful application as a device for waste heat energy harvesting and conversion. Thermoelectric generators (TEGs) have received increasing attention due to their potential to harvest low-grade heat energy (<100 °C) and provide power for the Internet of Things (IoT) and wearable electronic devices. Herein, a wood-based ordered framework is used to fabricate carbon nanotube/poly(3, 4-ethylenedioxythiophene) (CNT/PEDOT) wood aerogel for TEG. The prepared CNT/PEDOT wood aerogel with an anisotropic structure exhibits a low thermal conductivity of 0.17 W m −1 K −1 and is advantageous to develop a sufficient temperature gradient. Meanwhile, CNT/PEDOT composites effectively decouple the relationship between the Seebeck coefficient and electrical conductivity by energy filtering effect to enhance thermoelectric (TE) output properties. The vertical TEG assembled by the CNT/PEDOT wood aerogels reveals an output power of 1.5 μW and a mass-specific power of 15.48 μW g −1 at a temperature difference of 39.4 K. Moreover, the layered structure renders high compressibility and fatigue resistance. The anisotropic structure, high mechanical performance, and rapid thermoelectric response, enabling the TEG based on CNT/PEDOT wood aerogel offer opportunities for continuous power supply to low-power electronic devices.

A Self-Powered Sport Sensor Based on Triboelectric Nanogenerator for Fosbury Flop Training

Due to the high efficiency of low-frequency mechanical energy harvesting, wearable and flexible self-powered sport sensor based on triboelectric nanogenerators (TENGs) have become the hot research topic. Thus, we report a flexible and wearable cotton fabric (CF) coated with carbon oil- (CO-) based TENG (CC-TENG) with low processing costs, good electrical properties, and long working life. Meanwhile, we use a piece of flexible, microfibre-woven CF as the substrate for the CO. Moreover, the fibre surface characteristics of the cotton fabric provide higher surface roughness, which can make the TENG device work better. In detail, the CO layer serves as the triboelectric material and conductive electrode. According to the results, the CC-TENG shows good reliability, and the electric energy generated by CC-TENG can drive low-power electronic devices. Significantly, CC-TENG device can be applied to fosbury flop training to obtain training data and motion information monitoring, which will promote the wearable intelligent sports device.

Enhanced Triboelectric Effects of Self-Poled MoS2-Embedded PVDF Hybrid Nanocomposite Films for Bar-Printed Wearable Triboelectric Nanogenerators.

Self-poled molybdenum disulfide embedded polyvinylidene fluoride (MoS2@PVDF) hybrid nanocomposite films fabricated by a bar-printing process are demonstrated to improve the output performances of triboelectric nanogenerators (TENGs). Comparative analyses of MoS2@PVDF films with different MoS2 concentrations and the synergic effect based on postannealing at different temperatures were examined to increase the triboelectric open-circuit voltage and the short-circuit current (∼200 V and ∼11.8 μA, respectively). A further comprehensive study of the structural and electrical changes that occur on the surfaces of the proposed hybrid nanocomposite films revealed that both MoS2 incorporation into PVDF and postannealing can individually promote the formation of the β-crystal phase and generate polarity in the PVDF. In addition, MoS2, which provides triboelectric trap states, was found to play a significant role in improving the charge capture capacity of the nanocomposite film and increasing the potential difference between two electrodes of TENGs. The produced electrical energy of the developed wearable TENGs with excellent operational stability for a long duration was utilized to power a variety of mobile smart gadgets in addition to low-power electronic devices. We believe that this study can provide a simple and effective approach to improving the energy-harvesting capabilities of wearable TENGs based on hybrid nanocomposite films.

A novel seesaw-like piezoelectric energy harvester for low frequency vibration

This paper presents a novel seesaw-like piezoelectric energy harvester which has rotating motions to enhance the harvesting performance at low frequency vibrations. Firstly, the designing of the harvester with the specific structure was accomplished, and then the finite element analysis was conducted to simulate its dynamic characteristics. Finally, the prototype of the harvester was fabricated whose power generating behaviors were experimentally investigated. The influence of key structural parameters on the energy harvesting performance was evaluated by a combination of simulation and experiment. The effect of the inertia difference on the energy harvester characteristics was studied innovatively. The results indicated that the energy harvester reached the second-order resonance at a low frequency due to the adoption of the rotating shaft. And the piezoelectric material was involved in a significant strain due to the inertia difference between both ends of the beam. The efficiency of the harvester is relevant to the system moment of inertia and the excitation acceleration. The second-order resonant frequency of the harvester is as low as 19.18 Hz. When the excitation acceleration is 2.94 m/s2, the maximum output voltage and power of the harvester are 49.15 V and 4.03 mW respectively, which demonstrates the superior harvesting performance of the structure. This work can provide a novel method for designing efficient ambient energy harvesters supplying for low-power electronic devices.

Raman Effect Studies of Electrochemical Synthesized Quartz Crystal of Poly-O-Phenylenediamine for Piezoelectric Application

Microelectronics arose from the desire for miniaturization of electrical devices, while Nano-electronics arose from subsequent study. Researchers have developed and modeled energy harvesting technologies based on the conservation law of energy over the last two decades to produce an alternative power source for small size electronics (nano-electronics) and low power electronic devices that can replace traditional power sources like batteries. The ambient energy, which is typically in the form of solar, thermal, vibrational, and other types, can be converted into a variety of different forms. Electrical energy can be harvested from vibrational energy in materials and other man-made materials using piezoelectric, electromagnetic, electrostatic, and nano-electric generators. Poly-o-phenylenediamine (PoPD) Quartz (silicon dioxide) Crystals were electrochemically produced at varied percentage ratios of silicon dioxide and Poly-O-Phenylenediamine samples in this study (sample A represents 20:80 percent, sample B with 50:50 percent, and sample C has 60:40 percent respectively). The Raman Effect and Scanning Electron Microscopic (SEM) analysis were used to characterize the material and forecast its Piezoelectric effect. All of the samples have their maximum peak record at Raman shift of 2872cm-1, however the Raman intensity varies. Sample A produced a peak intensity of 1250, Sample B produced a peak intensity of 1700, and Sample C produced a peak intensity of 2700. As the doping concentration of silicon dioxide increases, the Raman peak intensity for Poly-o-Phenylenediamine doped with silicon dioxide increases. The SEM images show that Sample A forms a fine cluster with little or no distinctive morphology, Sample B is ball-shaped with grain-like structure, and Sample C shows a flat, thin leaf-like shape. From sample A to C, the intra-particle separation rises, which corresponds to an increase in SiO2 concentration.

Design and Experiment of Piezoelectric–Electromagnetic Composite Energy Trap Based on Human Motion

To realize the harvesting of energy generated by human movement, in this study, a piezoelectric–electromagnetic composite was designed for harvesting the energy generated by low-frequency human motion is designed by combining the principle of power generation and electromagnetic energy conversion of polyvinylidene fluoride (PVDF) piezoelectric materials. First, the structure and working principle of the piezoelectric–electromagnetic composite energy trap were designed and analyzed. Next, the system dynamics model of piezoelectric–electromagnetic coupling power generation was established, and the main influencing factors of the composite energy trap were derived. Moreover, the influence of PVDF piezoelectric materials with different size parameters on the output voltage and the influence of the frequency of the moving permanent magnet on electromagnetic power generation were analyzed. Finally, the prototype was constructed and tested. The results revealed that the output voltage of the piezoelectric–electromagnetic composite energy trap placed horizontally is higher than that of the composite energy trap placed vertically at step frequencies of over 90 steps/min, and the maximum output voltage is 25.6 V at the step frequency of 140 steps/min. The electric energy generated by the composite energy trap can supply power to low-power electronic devices, thus demonstrating the feasibility of collecting human-motion energy for power generation.

A Review of WSN Technologies for the Design of u-Healthcare Systems

Wireless Sensor Networks (WSNs) refer to a network of intelligent sensor nodes that are capable of monitoring physical and environmental conditions and can be deployed anywhere and anytime. The technological advancement in the integration of low-power electronic devices in the area of sensing, networking, and processing is rapidly increasing thus it pervasively changes the trends in healthcare systems. Efficient utilization of this emerging technology simplifies the monitoring and treatment of patients and enables high-quality, reliable, and emergent medical services. This study presents a review of WSNs capable of uplifting the design of u-Healthcare Systems enabling remote and continuous monitoring and thus providing immediate and effective medical services for patients.

Performance Analysis of 9T SRAM using 180nm, 90nm, 65nm, 32nm, 14nm CMOS Technologies

The growing markets for low-power electronic devices energized by battery have created the need for smaller power-efficient chips to prevent frequent charging of the source. Nowadays the market capitalization of low-power appliances is expected to grow from USD 4.9 billion by 2022 to USD 7.9 billion by 2027 as per global forecast to 2027 published by markets. The main factor leading to growth of low power electronics market includes demand of energy saving components, miniaturization, and entry of IoT (internet of things) devices. In addition, increased investment by automotive OEM (Original Equipment Manufacturer) and governments to promote the adoption of electric vehicles is expected to create more market opportunities. In this digital era, memory components play a major role in power consumption and this incites the research interest these days. CMOS (Complementary Metal Oxide Semiconductor) technology is growing rapidly towards greater integration into a single chip, resulting to a decrease in chip sizes using less space. Speed and stability demand is also growing up. Combined chip density increases as downtime technology continues. Stability and reliability are an important issue for the static random access memory (SRAM) memory device. In this paper, the design and analysis of CMOS based 9T SRAM cell in a variety of technologies is presented. The main focus of this review paper is to analyze 9T SRAM to test performance on several CMOS technologies (180nm, 90nm, 65nm, 45nm, 32nm, 14nm) with the help of a predictable technology (PTM) file. The butterfly curve method is used to examine the consistency of the SRAM bit cell in terms of static noise margin (SNM). It is clearly shown in this paper that as it progresses from 180nm to 14nm the delay decreases with stability.