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Orientation Dependence of Power Generation on Piezoelectric Energy Harvesting Using Stretched Ferroelectric Polymer Films
摘要： The piezoelectric vibration energy harvesters were fabricated by using uniaxially stretched poly (vinylidene difluoride/trifluoroethylene) copolymer (P(VDF/TrFE)) film, and the relationship between piezoelectric power generation and molecular orientation was investigated. The molecular orientation in the stretched P(VDF/TrFE) films was evaluated with polarized Fourier transfer infrared (FT-IR) spectra measurement. In stretched films, the main-chains of P(VDF/TrFE) were aligned along the stretching direction. The piezoelectric properties and the electric power generation of stretched P(VDF/TrFE) films were strongly depended on their molecular orientation, measuring by cantilever-type energy harvesters. The piezoelectric coefficient(e) and output power observed in the energy harvester with the film stretched in the longitudinal direction of cantilever were 16.9 mC/m2 and 222 nW, respectively. These values were approximately 2.1 and 3.5 times these of the unstretched elements.
关键词： P(VDF/TrFE),piezoelectric,molecular orientation,energy harvesting,ferroelectric polymer
更新于2025-09-10 09:29:36
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Bulk PZT Cantilever Based MEMS Acoustic Transducer for Cochlear Implant Applications
摘要： This paper presents the first acoustic experimental results of a MEMS based bulk piezoelectric transducer for use in fully implantable cochlear implants (FICI). For this purpose, the transducer was attached onto an acoustically vibrating membrane. Sensing and energy harvesting performances were measured using neural stimulation and rectifier circuits, respectively. The chip has a 150 Hz bandwidth around 1800 Hz resonance frequency that is suitable for mechanical filtering as a sensor. As an energy harvester, bulk piezoelectric transducer generated a rectified power of 16.25 μW with 2.47 VDC with 120 dB-A sound input at 1780 Hz. Among other MEMS acoustic energy harvesters in the literature, reported transducer has the highest power density (1.5 × 10?3 W/cm3) to our knowledge.
关键词： bulk PZT,acoustic energy harvesting,energy harvesting,cochlear implants
更新于2025-09-09 09:28:46
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Handbook of Smart Cities (Software Services and Cyber Infrastructure) || Energy Harvesting in Smart Building Sensing: Overview and a Proof-of-Concept Study
摘要： Modern “smart” buildings require a plethora of sensors to be installed at various locations during the construction phase. Wiring costs and limited ?exibility of installation make wired installations less attractive. An alternative, ?exible, approach is to introduce wireless sensors and endow them with ways to harvest energy from the environment such that they attain the same “zero cost” of maintenance as their wired counterparts. The chapter reviews the sensing needs of smart buildings, and the related merits of energy harvesting to power embedded wireless sensor nodes. A proof-of-concept device exploiting thermoelectric harvesting is designed, built and tested to demonstrate how todays wireless sensing devices enable sustained continuous operation with minor energy harvesting requirements. In multi-hop environments, the underlying optimization problems are described and simple strategies that forego the solution of the hard computation problems but appear effective are outlined.
关键词： thermoelectric harvesting,smart buildings,energy harvesting,wireless sensor networks,multi-hop environments
更新于2025-09-09 09:28:46
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Use it or lose it: The influence of second order effects of practical components on storing energy harvested by pyroelectric effects
摘要： Harvesting energy using the pyroelectric effect has seen growth as a potential energy source for low power applications, such as self-powered and autonomous wireless sensor networks. The scavenged energy is generally at low power levels, from mW to less than μW. While the voltages generated by pyroelectrics can be appreciable, the electric currents can be low in the order of nano-amps. In the case of pyroelectric harvesting the frequency of operation can also be low, typically much lower than 1 Hz, due to the slow temperature oscillations and transients in systems of large thermal mass. The combination of low power levels and low frequency of operation means that methods of storing electrical energy generated by pyroelectrics and the influence of inherent second order losses is of importance to create efficient harvesting devices. This paper examines the second order characteristic effects of practical capacitors and diodes for storage. The stored energy decay characteristics for commercially available components are examined and the data is used to characterise the second order effects. Selected components are then used in a pyroelectric harvesting system to determine potential improvements by appropriate selection of components with low loss.
关键词： pyroelectric,Energy-harvesting,energy-storage
更新于2025-09-09 09:28:46
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[ASME ASME 2015 Conference on Smart Materials, Adaptive Structures and Intelligent Systems - Colorado Springs, Colorado, USA (Monday 21 September 2015)] Volume 2: Integrated System Design and Implementation; Structural Health Monitoring; Bioinspired Smart Materials and Systems; Energy Harvesting - A Sub-Surface Model of Solar Power for Distributed Marine Sensor Systems
摘要： The capabilities of distributed sensor systems, such as wildlife telemetry tags, could be significantly enhanced through the application of energy harvesting. For animal telemetry systems, supplemental energy would allow for longer tag deployments, wherein more data could be collected, enhancing our temporal and spatial comprehension of the hosts activities and/or environments. There are various transduction methods that could be employed for energy harvesting in aquatic environments. Photovoltaic elements have not been widely deployed in the sub-surface marine environments despite a significant potential. In addition to wildlife telemetry systems, photovoltaic energy harvesting systems could also serve as a means of energy supply for Autonomous Underwater Vehicles (AUVs), as well as submersible buoys for oceanographic data collection. Until now, the use of photovoltaic cells for underwater energy harvesting has generally been disregarded as a viable energy source in this arena, with only one company currently offering solar modules integrated with marine telemetry tags. In this article, we develop a model of power available from photovoltaic cells deployed in a sub-surface marine environment. We cover the methods and tools used to estimate solar energy at depth, including the effects of: latitude and longitude, reflected solar energy off of the oceans surface, solar irradiance lost due to the absorption and turbidity of the sea water, cloud cover, etc. We present the availability of this solar energy source in the context of the energy requirements of some of these sensor systems, such as marine bio-loggers. Additionally, we apply our model to simulate the energy harvested on specific marine species in which high fidelity depth information is known. We also apply our model to simulate solar cells at certain depths under the ocean to gain a general understanding of the solar energy available at these depths.
关键词： sub-surface marine environment,photovoltaic cells,marine telemetry,solar energy,energy harvesting
更新于2025-09-09 09:28:46
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Encyclopedia of Wireless Networks || Energy Modeling for Nanoscale Terahertz Communication
摘要： Energy modeling for nanoscale terahertz communication is required to investigate the relationship between energy harvesting and consumption in nanoscale terahertz communication and analyze the trade-off between them by jointly considering the constraints of nanonetworks and the peculiarities of terahertz communications, in order to achieve perpetual nanonetworks.
关键词： Energy consumption,Nanoscale communication,Terahertz,Energy harvesting
更新于2025-09-09 09:28:46
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Wide band fractal-based perfect energy absorber and power harvester
摘要： In this article, a novel wide band polarization and incident angle independent meta-material absorber (MA) and energy harvesting applications which operates at C (4GHz-8 GHz) and X (8GHz-12 GHz) is proposed. The unit-cell of the proposed structure based on fractal circle loop. Four lumped resistors are mounted the structure to obtain a broad band absorption characteristics. Resistors increase the absorption characteristic of proposed MA significantly at mentioned frequency ranges. In addition, under favor of the resistors proposed MA can convert absorbed energy from incident wave to appearing power.
关键词： metamaterial,wide band absorber,energy harvesting,fractal metamaterial absorber
更新于2025-09-09 09:28:46
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A cm-Scale 2.4-GHz Wireless Energy Harvester With NanoWatt Boost Converter and Antenna- Rectifier Resonance for WiFi Powering of Sensor Nodes
摘要： The widespread use of WiFi in the 2.4-GHz ISM band creates the potential for RF powering using WiFi radios. This paper presents the design of a cm-scale RF-energy harvester including antenna, rectifier, and dc–dc boost converter for RF powering in the 2.4-GHz ISM band. The rectifier and boost converter are designed while considering cold-start operation and nanowatt-scale available power from the rectifier for RF incident power <?33 dBm. Low-power design in the power management unit and converter leads to ～1-nW quiescent power. The harvester implementation in 65-nm CMOS occupies 1.6 mm2 while the antenna occupies 1.27 cm2. The proposed design optimization approach leads to a sensitivity of ?33 dBm in cold start and ?36 dBm in the primary mode for 1-V output, translating to ～1.4× and ～2× improvement in range compared to prior art. Measurements using a commercial WiFi TX demonstrate the ranges of up to 1.25 m for 14-dBm output power with 1.3% TX duty-cycling in WiFi access-point mode, demonstrating the feasibility of powering sensors from RF power beacons in the 2.4-GHz ISM band as well as from background WiFi transmissions.
关键词： wireless powering,co-design,Antenna,ultralow power,WiFi charging,power management,sensitivity,boost converter,rectifier,RF,cold start,energy harvesting
更新于2025-09-09 09:28:46
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Future prospects of fluoride based upconversion nanoparticles for emerging applications in biomedical and energy harvesting
摘要： Rare earth doped/codoped phosphors have been extensively studied for different types of applications based on their intense luminescence features. For this, researchers have tried to choose the inorganic host matrices having both a low phonon cut-off frequency and a high refractive index. Many articles have been published on oxide based phosphor materials, but due to their high cut-off phonon frequency, use of these materials is restricted for optical based applications. This is why additional research has been carried out on fluoride based host materials because of their low phonon frequencies, low composition degradation, and high quantum efficiency. In this paper, the authors review the rare earth fluoride based host nano- and micromaterials for different applications and discuss possible mechanisms.
关键词： biomedical applications,fluoride based upconversion nanoparticles,energy harvesting,luminescence,rare earth doped phosphors
更新于2025-09-09 09:28:46
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Ultrafast Fabrication of Thermoelectric Films by Pulsed Light Sintering of Colloidal Nanoparticles on Flexible and Rigid Substrates
摘要： Sintered thermoelectric (TE) nanoparticle films are known to have a high figure-of-merit ZT factor and are considered for waste heat recovery and heating and cooling applications. The conventional process of thermal sintering of TE nanoparticles requires an inert environment and long heating times, and cannot be used on polymer substrates due to the requirements of the process (e.g., heating up to 400 °C). In this communication, the authors demonstrate for the first time the use of an intense flash of UV light from a Xenon lamp to sinter TE nanoparticles within milliseconds under ambient conditions on flexible polymer as well as glass substrates to create functional TE films. Photonic sintering is used to fabricate Bismuth Telluride thermoelectric films with a conductivity of 3200 S m?1 (a 5–6 orders of magnitude increase over unsintered films) and a peak power factor of 30 mW m?1 K?2. Modeling is used to gain an insight into the physical processes occurring during photonic sintering process and identify the critical parameters controlling the process. This work opens-up an exciting possibility of extremely rapid fabrication of TE generators under ambient conditions on a variety of flexible and rigid substrates.
关键词： power factor,ZT factor,thermoelectrics,Bi-Te nanoparticles,energy harvesting,photonic sintering
更新于2025-09-09 09:28:46