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Internal-field-dependent low-frequency piezoelectric energy harvesting characteristics of in situ processed Nb-doped Pb(Zr,Ti)O3 thin-film cantilevers
摘要： Piezoelectric thin-film-based cantilevers have been investigated for higher energy-harvesting performance with simplified processing steps. Here, a simple in situ film deposition process of heavily Nb-doped lead zirconate titanate (PZT) films, which does not require annealing and poling, has been demonstrated to verify the possibility of use of the resultant films as energy-harvesters specifically for low frequency vibrating sources. The in situ domain formation of the films during the deposition was demonstrated from the apparent shifts of the capacitance-electric field curves, indicating the presence of internal electric fields. The so-called imprint behavior was found to be directly related to the performance of piezoelectric energy harvesting. As an optimal example, 12 mol% Nb-doped cantilever harvesters that showed the largest imprint behavior exhibited the best values of ~19.1 GPa figure-of-merit and ~1436 mWcm?3g?2 power density, which are competitive compared to other reported values.
关键词： Thin films,Cantilevers,Piezoelectric energy harvesting,Nb-doping,PZT
更新于2025-09-23 15:23:52
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An Eco-friendly Flexible Piezoelectric Energy Harvester That Delivers High Output Performance is Based on Lead-Free MASnI3 Films and MASnI3-PVDF Composite Films
摘要： An environmentally-friendly lead-free methylammonium tin iodide (MASnI3) perovskite is successfully synthesized using a facile approach of an antisolvent-assisted collision technique under room ambient conditions, which results stability within 24 h under ambient room conditions. The phase transition of MASnI3 from tetragonal to cubic is first observed at ~ 30 °C. Polycrystalline MASnI3 films reveal a high dielectric constant of ~ 65 at 100 kHz, a low-leakage current density of 7 × 10-7 A cm-2 at 50 kV cm-1, well-developed P-E hysteresis loops, and a high piezoelectric coefficient (d33) of 20.8 pm V-1. The MASnI3 piezoelectric energy nanogenerator (PENG) shows an output voltage of ~ 3.8 V and an output current density of 0.35 μA cm-2. To enhance the piezoelectric output performance, the MASnI3 films are composited with an environmentally friendly PVDF polymer that had a porous structure. The PVDF-MASnI3 composite based-PENG reveals a maximum output voltage of ~ 12.0 V and current density of ~ 4.0 μA cm-2. A green light-emitting diode (LED) using the PVDF-MASnI3 PENGs is instantly lighted without need of a storage device, and long-term stability of the composite PENGs is validated for 90 days. This simple and cost-effective solution process is feasible for the fabrication of large-scale, high-performance, and environmental-friendly PENGs based on lead-free organic-inorganic perovskites to extensively implicate in medical and biomechanical applications.
关键词： Dielectric property,Lead-free MASnI3,PVDF-MASnI3 composite PENGs,Piezoelectric energy,Antisolvent-assisted collision technique
更新于2025-09-23 15:23:52
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Generalized optimization method for energy conversion and storage efficiency of nanoscale flexible piezoelectric energy harvesters
摘要： The energy conversion and storage efficiency was commonly ignored in experimental studies on nanoscale flexible piezoelectric energy harvesters (PEHs). In this study, we develop a generalized theoretical method to optimize the energy conversion and storage efficiencies of nanoscale flexible PEHs. The results are validated by comparisons with experimental measurements for various ambient excitations. A simple scaling law is established to reveal the intrinsic correlation between the efficiency of energy conversion/storage and various system parameters of the PEHs. For either the energy conversion or storage circuit, the output power density may be maximized by properly designing an intrinsic normalized parameter. Furthermore, we demonstrate that an independent optimization criterion is indispensable for standard storage circuits since including a storage module into the conversion circuit redefines the electromechanical behavior of the PEH system. The results may be used as guidelines for optimizing the energy conversion and storage efficiencies of nanoscale flexible PEHs that have promising applications in harvesting biomechanical energies.
关键词： Scaling law,Optimization,Nanoscale flexible piezoelectric energy harvesters,Energy conversion,Energy storage
更新于2025-09-23 15:22:29
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dSPACE Controller Based Enhanced Piezoelectric Energy Harvesting System Using PI-Lightning Search Algorithm
摘要： This paper presents a new lightning search algorithm (LSA) to enhance the piezoelectric energy harvesting system converter (PEHSC) using the dSPACE DS1104 controller board as the proportional-integral voltage controller (PIVC). To extract the energy from the vibration is challenging and difficult due to the uncertain behavior of vibration. Since the piezoelectric vibration transducer generates low AC voltage output with fluctuations and harmonics, it is difficult to control this low-level signal of various magnitudes. Therefore, the behavior of the converter is governed by its controller. The traditional PIVC process for improved parameter values of proportional gain (Kp) and integral gain (Ki) is commonly implemented via trial and error, which does not lead to an acceptable response in several conditions. Hence, this paper offers a method for finding the optimal Kp and Ki values for PIVC that eliminates the time-consuming conventional trial-and-error process. This method is applied to PEHSC development by producing values of Kp and Ki performed in the PIVC depending on the estimated outcomes of the objective function defined via LSA. The mean absolute error (MAE) is used as the objective function for reducing the output error of the PEHSC. The LSA optimizes the Kp and Ki values that give the minimum MAE, and the effect on the PEHSC is in terms of the rising and settling times. The development process and efficiency of the PIVC are demonstrated and examined via simulations using the MATLAB tools. The LSA-based PIVC (LSA-PI) is compared with the particle swarm optimization (PSO)-based PIVC (PSO-PI) and the backtracking search algorithm (BSA)-based PIVC (BSA-PI). The performance of the LSA-PI-based PIVC is then validated through hardware implementation using the dSPACE DS1104 control board. The simulation results are compared with the hardware results of PEHSC to validate the overall efficiency of the system. Finally, the results are regulated at an output of 7 V DC from an input range of 150 mV～250 mV AC at 30 Hz through a closed-loop using the LSA-PIVC.
关键词： PI controller,optimization,Piezoelectric energy harvesting,dSPACE controller
更新于2025-09-23 15:22:29
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[IEEE 2018 IEEE International Ultrasonics Symposium (IUS) - Kobe, Japan (2018.10.22-2018.10.25)] 2018 IEEE International Ultrasonics Symposium (IUS) - Lead-Free Sodium Potassium Niobate Based Piezoelectric Thick Film Bimorph Structure for Energy Harvesting
摘要： A novel piezoelectric ceramic-based bimorph energy harvester (PEH) is proposed in this paper for scavenging energy from low-frequency vibrations in many types of applications, such as in the human body or in industry. The PEH is based on a lead-free piezoelectric ceramic material (NKN-based) and is designed to operate efficiently at frequencies below 100 Hz. Experimental results show that the device can generate a power density of up to 22 μW/cm3 under an acceleration of 1 g at 20 Hz, which is highly competitive with existing energy harvesters. This work demonstrates the potential of using lead-free materials for sustainable energy harvesting technologies.
关键词： piezoelectric energy harvesting,NKN-based materials,low-frequency vibrations,lead-free ceramics,bimorph structure
更新于2025-09-23 15:22:29
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[ASME ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference - Quebec City, Quebec, Canada (Sunday 26 August 2018)] Volume 8: 30th Conference on Mechanical Vibration and Noise - Piezoelectric Nonlinear Energy Sink for Energy Harvesting With Rectifying DC Interface Circuit
摘要： In order to improve the performance of vibration energy harvesters over a broad frequency range, this paper proposes a use of piezoelectric nonlinear energy sink (NES) for energy harvesting from ambient vibrations. A standard rectifying direct current (DC) interface circuit is considered to generate DC power from the piezoelectric NES under harmonic excitation. Harmonic balance method is used to obtain the dynamic response and energy harvesting performance of the proposed piezoelectric NES, verified by the equivalent circuit simulation. Analytical and numerical results show that the design, by applying NES, improves the efficiency of energy harvesting without increasing the vibration of the primary structure in a broadband manner. The effects of the electromechanical coupling, excitation level and load resistance on the magnitude and bandwidth of the output DC power are investigated.
关键词： harmonic excitation,rectifying DC interface circuit,piezoelectric,energy harvesting,nonlinear energy sink
更新于2025-09-23 15:21:01
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[ASME ASME 2018 Conference on Smart Materials, Adaptive Structures and Intelligent Systems - San Antonio, Texas, USA (Monday 10 September 2018)] Volume 2: Mechanics and Behavior of Active Materials; Structural Health Monitoring; Bioinspired Smart Materials and Systems; Energy Harvesting; Emerging Technologies - Experimental Studies on a Compressive-Mode Piezoelectric Transducer for Low-Frequency and Wide-Band Energy Harvesting
摘要： In this paper, we report a low-frequency and wide-bandwidth piezoelectric energy transducer. The transducer is designed based on a piezoelectric plate, a truss mechanism, a spring-mass system and a stopper. The spring-mass system receives kinetic energy from excitation and induces forces, which are transmitted, amplified by truss mechanism and applied onto the piezoelectric plate. The stopper is added to truncate the amplitude of the mass. The mass and the stopper interact through impacts. The impact force triggers dynamic bifurcation in the transducer. By taking advantage of the superharmonic resonances and nonlinearity born from the bifurcation, the transducer is able to work efficiently with a wide bandwidth. Through experiment studies on a fabricated prototype, the lowest resonant frequency is around 3.2Hz with the peak-peak voltage output up to 55V. The bandwidth of the transducer is approximately 4.5Hz out of our targeted frequency domain [2.5Hz, 10Hz], broadened by up to 20 times compared to that of the linear system without the stopper.
关键词： superharmonic resonances,wide-bandwidth,low-frequency,piezoelectric energy transducer,nonlinearity
更新于2025-09-10 09:29:36
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Effect of elastic modulus of cantilever beam on the performance of unimorph type piezoelectric energy harvester
摘要： Piezoelectric energy harvesting is a technique that can utilize ambient vibration energy to generate useful electrical energy, which is promising for powering small-scale autonomous devices such as sensors for wearable, biomedical, and industrial applications. Typically, cantilever-type piezoelectric energy harvesters (PEHs) are operated under resonance condition to achieve the maximum output power at low frequency stimuli. Along with resonance matching, it is also necessary to optimize the PEH configuration with high electromechanical properties for the efficient energy conversion. The purpose of this study is to investigate the effect of the elastic modulus of the passive layer in the cantilever structured PEH on the electromechanical properties and thus harvesting performance. In this regard, two unimorph type PEHs having the identical geometry, piezoelectric properties, and proof mass but with different elastic modulus (55 GPa and 97 GPa) of Ti alloy-based passive layers were fabricated and their output performance was compared under the same acceleration amplitude excitation stimuli. The PEH with the smaller elastic modulus passive layer exhibited almost 53% improvement in the maximum power than that with the higher elastic modulus passive layer, which is attributed to a smaller mechanical damping ratio, higher quality factor, and larger vibration amplitude.
关键词： vibration energy,piezoelectric energy harvesting,cantilever beam,elastic modulus,unimorph type
更新于2025-09-04 15:30:14
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Effect of a-Si thin film on the performance of a-Si/ZnO-stacked piezoelectric energy harvesters
摘要： In this letter, we present the fabrication and characterization of a zinc oxide (ZnO)-based nanogenerator for piezoelectric micro-energy harvesting by combining thin films of amorphous silicon (a-Si) and ZnO. We utilized the a-Si thin film as an interlayer to assemble several a-Si/ZnO-stacked piezoelectric nanogenerators (SZPNGs) on indium tin oxide (ITO)-coated polyethylene naphthalate substrates. We investigated the influence of the a-Si layer thickness on the output voltages of the SZPNGs and demonstrated the existence of an optimal a-Si thickness for maximizing the output voltage. Overall, the SZPNGs generated higher output voltages than a conventional ZnO-based piezoelectric nanogenerator (ZPNG) lacking an a-Si interlayer, indicating enhanced performance. In particular, the SZPNG based on the optimal a-Si thickness exhibited a sixfold higher output voltage compared with the conventional ZPNG. This improved performance was ascribed to a combination of the Schottky barrier at the ITO/a-Si interface, preventing the screening effect and the relatively high dielectric constant (er≈13) of a-Si, minimizing the loss of the piezoelectric potential induced in the ZnO layer. The results herein are expected to assist the development of even more advanced ZnO-based piezoelectric nanogenerators in the future.
关键词： piezoelectric energy harvesting,zinc oxide,amorphous silicon,Schottky barrier,nanogenerator
更新于2025-09-04 15:30:14