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Fabrication of PAN/ZnO Nanofibers by Electrospinning as Piezoelectric Nanogenerator
摘要： Piezoelectric nanogenerator is a material that is used for converting mechanical energy to electrical energy. This research aimed to study the piezoelectric nanogenerator properties in PAN/ZnO nanofibers layered on the stainless-steel substrate. ZnO nanoparticles that were used in this work were synthesized by coprecipitation method. The ZnO nanoparticles were mixed with PAN dissolved with DMF. Fabrication of PAN-ZnO nanofibers was done using the electrospinning method on the stainless-steel substrate. The formed PAN/ZnO nanofibers were then characterized using XRD, SEM, and FTIR. To test the piezoelectric nanogenerator properties, PAN/ZnO nanofibers were combined to PAN nanofibers and coated on the stainless-steel substrate to form piezoelectric nanogenerator device. This device was then connected to an electrometer and an oscilloscope to measure the current and voltage resulted after bending. The results of XRD of ZnO nanoparticles had the wurtzite crystal structure with the size of about 46 nm. Meanwhile, the PAN/ZnO had an amorphous structure. The test results of piezoelectric nanogenerator properties showed the value of voltage and current of 7.22 V and 47.48 μA, respectively. PAN/ZnO nanofibers on the stainless-steel substrate are potential to be the material of piezoelectric nanogenerators in general.
关键词： electrospinning,PAN/ZnO nanofiber,energy harvesting,piezoelectric nanogenerator
更新于2025-09-23 15:23:52
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High room-temperature pyroelectric property in lead-free BNT-BZT ferroelectric ceramics for thermal energy harvesting
摘要： Pyroelectrics are attracting increasing attention because they enable pyroelectric generators to extract energy from low-gradient-temperature heat for portable electronic devices. High pyroelectric coefficient around room temperature is essential for high-performance energy harvesters, which, unfortunately, is only commonly achieved in lead-based ferroelectrics. Herein we report a high room temperature pyroelectric response of 27.2 × 10-4 C m-2 K-1 in 0.94(Bi0.5Na0.5)TiO3-0.06Ba(Ti0.75Zr0.25)O3 lead-free ceramics by modulating the Zr4+/Ti4+ ratio to tune the ferroelectric-relaxor antiferroelectric-like phase transition point to around ambient temperature, whose pyroelectric response is one order of magnitude higher than that of the sample without Zr and even comparable to those of lead-containing pyroelectrics. The theoretical analysis revealed that introduced Zr4+ could incorporate into the TiO6 octahedral lattices and break the long-range translational symmetry of BaTiO3 lattices, resulting in the reduction of B-site ion displacement activation energy and transition point of ferroelectric-relaxor antiferroelectric-like phase, giving rise to a pronounced room-temperature pyroelectric effect in BNT-BZT.
关键词： BNT-BZT ceramics,Energy harvesting,Room temperature pyroelectric property,Phase transition
更新于2025-09-23 15:23:52
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A passive SPICE model for rectennas
摘要： Purpose – This paper aims to present a SPICE model to represent antennas in receiving mode. The model can be used to evaluate the performance of the antenna when it is coupled to several different nonlinear electric circuits. The proposed methodology is particularly suitable for rectenna applications, as it allows the analysis of different configurations for a rectenna more efficiently than using full-wave analysis simulators coupled directly to each rectifier circuit. Design/methodology/approach – The model presented uses reciprocity theory to calculate the ideal voltage source of the Thevenin-equivalent circuit for an antenna. Vector fitting is then used to approximate the model to rational functions that can be converted to Resistor, Inductor and Capacitor circuits. Additional components are added to the circuit to prevent numerical instability. Findings – Two rectennas are used to illustrate the performance of the proposed model, one based on a 2.45-GHz rectangular patch antenna and another based on a planar spiral antenna. The second antenna has impedance with positive and negative real parts along the frequency range, which could lead to numerical instabilities. The proposed method is shown to be stable while working with these negative resistance values, which may appear during circuit parameterization. Research limitations/implications – The equivalent SPICE circuit model for the antenna makes it easy to simulate nonlinear circuits connected to the antenna and perform transient analyses. The computational cost of antenna analysis is reduced, being more computationally efficient than methods that involve full-wave simulation. This characteristic makes it an interesting approach for working with rectennas, or any application where the time constant of the circuit is much longer than the period of the incident wave. Originality/value – For most antenna applications, the numerical stability of the circuit can be achieved using passive enforcement. However, depending on the phase response of the antenna, the impedance that represents its far-field characteristic may present a negative real part, in which case, passive enforcement will fail. In this paper, the problem of numerical instability is solved by introducing an offset resistance and a current-controlled voltage source to the model.
关键词： Antenna,SPICE model,Rectenna,Energy harvesting
更新于2025-09-23 15:23:52
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Integration of organic/inorganic nanostructured materials in a hybrid nanogenerator enables efficacious energy harvesting via mutual performance enhancement
摘要： Recent reports demonstrate that hybrid energy harvesting devices can efficiently convert ubiquitously available but mostly unexploited ambient energies (e.g., mechanical, chemical, thermal, solar) into usable power that can potentially support a new generation of self-powered electronic systems. In this paper, we present a hybrid organic/inorganic nanogenerator on shim substrates, which integrates both piezoelectric and triboelectric components based on inorganic p-n junction ZnO nanostructures and nanostructured organic polytetrafluoroethylene (PTFE) film, respectively. In this design, individual components can be operated independently or concurrently. Moreover, when operated concurrently, component performance is mutually enhanced, enabling more efficient conversion of mechanical energy into electrical energy in a single press-and-release cycle. When triggered with 25 Hz frequency and 1G acceleration of external force, the piezoelectric nanogenerator (PENG) component generates a peak-to-peak output voltage of 34.8V, which is ～3 times higher than its output when it acts alone. Similarly, the triboelectric nanogenerator (TENG) component generates a peak-to-peak output voltage of 356V under the same conditions, which is higher than its initial output of 280V when acting alone. The nanogenerator unit produces an average peak output voltage of 186 V, current density of 10.02 μA/cm2, and average peak power density of 1.864 mW/cm2 when operated in the hybrid configuration. The device can even produce an average peak-to-peak voltage of ~160V from normal hand movement when placed under a wristband fitness tracker, and ~580V from human walking when placed within the walker’s shoe. The device has been demonstrated to charge commercial capacitors up to a few volts within several seconds.
关键词： nanoplates,energy harvesting,hybrid nanogenerators,nanowires,piezoelectricity,triboelectricity
更新于2025-09-23 15:23:52
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Why environmental dust influences solar energy harvesting
摘要： In order to minimize dust effects on optical surfaces related to the solar energy harvesting, adhesion between the active surface of energy harvesting device and the dust particles needs to be lowered. Consequently, the pinning force for the dust particles reduces, and the dust particles can be removed via creating the self‐cleaning effect. The wetting state of the active surface becomes critical towards reducing the pinning force. In this case, hydrophobic surfaces remain favorable reducing the dust adhesion on the surfaces. In the present perspective, characteristics of the environmental dust particles and their effects in humid air ambient are presented. The methods for dust removal from the surfaces and the optical transmittance reduction by the dust particles are discussed. The challenges and future perspectives of surface texturing towards achieving hydrophobicity and optical transmittance are also introduced.
关键词： environmental dust,solar energy harvesting,optical transmittance
更新于2025-09-23 15:23:52
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Parametric Study and Optimization of Linear and Nonlinear Vibration Absorbers Combined with Piezoelectric Energy Harvester
摘要： In this work, a harmonically excited generalized two degree of freedom non-linear system is used to manifest the functions of both the vibration absorber and energy harvester simultaneously. The generalized system has been reduced to a linear primary system with linear/nonlinear absorber and harvester or nonlinear primary system with linear/nonlinear absorber and harvester. Multi-harmonic balance method (MHBM) along with arc length continuation is used for generating frequency response plots for different absorber and energy harvester system parameters with constant primary system parameters and excitation amplitude. The frequency response plots show multiple branches of stable periodic solutions and jump at certain frequency ranges for systems with nonlinearity. The absorber and energy harvester parameters are optimized using an optimization procedure based on genetic algorithm in combination with response surface methodology. The method is validated with analytical solutions available in the literature for a linear primary system with linear absorber and harvester and nonlinear primary system with nonlinear absorber alone. This study demonstrates that the proposed optimization framework along with MHBM is suitable for generating the optimal frequency response for multifunctional energy harvesting systems or systems with nonlinear absorber. The frequency response plots with optimal parameter values reiterates the fact that the absorber system with nonlinear element perform better compared to its linear counterpart over a wider band of frequencies. The study also reports the comparison of the performance of a combined nonlinear absorber harvester system with that of a nonlinear energy sink (NES) absorber harvester system.
关键词： vibration absorber,multi-harmonic balancing,energy harvesting,optimization,response surface method,genetic algorithm
更新于2025-09-23 15:23:52
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A Generic Receiver Architecture for MIMO Wireless Power Transfer With Nonlinear Energy Harvesting
摘要： This letter investigates a multiple-input multiple-output (MIMO) wireless power transfer system under practical nonliner energy harvesting (EH) models. We propose a new generic energy receiver (ER) architecture consisting of N receive antennas and L recti?ers, for which one power splitter is inserted after each antenna to adaptively split the received radio frequency (RF) signals among the L recti?ers for ef?cient nonlinear RF-to-direct current (dc) conversion. With the proposed architecture, we maximize the total harvested dc power at the ER, by jointly optimizing the transmit energy beamforming at the energy transmitter and the power splitting ratios at the ER. Numerical results show that our proposed design by exploiting the nonlinearity of EH signi?cantly improves the harvested dc power at the ER, as compared to two conventional designs.
关键词： Wireless power transfer (WPT),non-linear energy harvesting (EH),transmit energy beamforming,adaptive power splitting
更新于2025-09-23 15:22:29
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Energy Harvesting Wireless Communications || Energy Harvesting in Next-Generation Cellular Networks
摘要： To handle the explosive growth of mobile traffic, next-generation cellular network will deploy more and more small-cell BSs (SBSs) in addition to the macro base stations (MBSs). The resultant network, namely, the heterogeneous network (HetNet), provides capacity boost on one hand but brings more energy consumption with the densely deployed SBSs on the other hand. In fact, due to the dynamics of wireless traffic load, many BSs are lightly loaded but almost work at their peak power, due to the elements like power amplifiers and supporting circuits. Unfortunately, these BSs can hardly be turned off for the coverage guarantee. To solve this problem, a new separation architecture called hyper-cellular network (HCN) is proposed, and the main idea is to decouple the function of control signaling from the function of data transmission, such that the data coverage can match the traffic dynamics in a more elastic way. Under HCN, SBSs are only utilized for high data rate transmission, whereas MBSs guarantee the network coverage and provide low data rate service. Therefore, SBSs can be turned off to save energy without worrying about the user coverage. To this end, its nature is to further power SBSs with renewable energy to save more grid power consumption. However, due to the randomness of renewable energy arrivals, it is challenging to manage wireless resource and the on-off states of energy harvesting (EH) BSs. It can be more challenging in HCN. First, diverse types of SBSs may be equipped with different kinds of energy sources, making the energy arrival statistically nonuniform over the space. In addition, the traffic load is nonevenly distributed across different base station (BS) tiers and also not in accordance with the energy arrivals over the spatial and temporal domains. To this end, on top of the techniques introduced in Chapter 4, in HCN the key to match the random energy arrival with the traffic load variation over time and space is to jointly optimize the working states of SBSs and the user traffic offloading. Although traffic offloading has been extensively studied in grid-powered cellular networks, the conventional offloading methods cannot be directly applied as they do not consider the energy states of BSs. Accordingly, energy-aware traffic offloading schemes are needed, and some energy-aware traffic offloading schemes have been proposed for single-tier homogeneous networks and two-tier HCN with one renewable energy-powered SBS, respectively. In the first part of the chapter, we will illustrate how to coordinate the on-off switching of SBSs with inter-tier traffic offloading, under the scenario with different types of SBSs, powered by various energy sources. The goal is to minimize the on-grid power consumption of the whole HCN system while satisfying the quality of service (QoS) requirements of users. Another emerging technology of next-generation cellular networks is to exploit edge caching with proactive services, like push. While the initial motivation of proactive caching and push is to reduce the duplicated content transmissions, and thus reduce the core network traffic load as well as the content delivery delay, it is also beneficial to address the mismatch between the energy and traffic in renewable energy-powered SBSs. Specifically, the contents can be cached at the storage of SBSs and then pushed to users earlier than the actual demands when there is sufficient harvested energy. The users can successfully get the contents when they actually require it even if at that time the SBS does not have enough energy for transmission. Consequently, the energy waste due to the battery overflow can be avoided as the harvested energy can be used effectively and timely. It can be viewed as transferring the harvested energy along with the timeline to the future to match the random energy arrival with the traffic needs. In the second part of this chapter, we will demonstrate the concept of integrating proactive service provisioning with EH HCN and provide a detailed study on the optimal policy design for content push from an EH-based SBS.
关键词： push,cellular networks,renewable energy,proactive caching,traffic offloading,quality of service,small-cell base stations,Markov decision process,Energy harvesting,hyper-cellular network
更新于2025-09-23 15:22:29
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[IEEE 2018 10th International Conference on Wireless Communications and Signal Processing (WCSP) - Hangzhou, China (2018.10.18-2018.10.20)] 2018 10th International Conference on Wireless Communications and Signal Processing (WCSP) - Energy Depositing for Energy Harvesting Wireless Communications
摘要： Energy borrowing (EB) technique has been proposed recently to improve the performance of wireless communications, which also decreases the burden of the smart grid (SG). To further reduce the burden of SG, we propose an energy depositing (ED) strategy. Specifically, the energy harvesting (EH) device can deposit its unused energy in the SG for decreasing the burden of SG, and it also can extract the deposited energy with additional amount of energy as incentive. An EB-and-ED structure is also proposed to promote a more energy-efficient wireless system. This paper focuses on the ED process, a joint optimization of both ED policy and power scheduling for maximizing the system throughput has been formulated. The simulation results using real solar irradiance data confirm the effectiveness of the proposed ED strategy.
关键词： energy depositing,energy harvesting,throughput
更新于2025-09-23 15:22:29
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Learning-based Computation Offloading for IoT Devices with Energy Harvesting
摘要： Internet of Things (IoT) devices can apply mobile edge computing (MEC) and energy harvesting (EH) to provide high level experiences for computational intensive applications and concurrently to prolong the lifetime of the battery. In this paper, we propose a reinforcement learning (RL) based offloading scheme for an IoT device with EH to select the edge device and the offloading rate according to the current battery level, the previous radio transmission rate to each edge device and the predicted amount of the harvested energy. This scheme enables the IoT device to optimize the offloading policy without knowledge of the MEC model, the energy consumption model and the computation latency model. Further, we present a deep RL based offloading scheme to further accelerate the learning speed. Their performance bounds in terms of the energy consumption, computation latency and utility are provided for three typical offloading scenarios and verified via simulations for an IoT device that uses wireless power transfer for energy harvesting. Simulation results show that the proposed RL based offloading scheme reduces the energy consumption, computation latency and task drop rate and thus increases the utility of the IoT device in the dynamic MEC in comparison with the benchmark offloading schemes.
关键词： Mobile edge computing,energy harvesting,reinforcement learning,computation offloading,Internet of Things
更新于2025-09-23 15:22:29