Pub Date : 2019-12-01DOI: 10.1109/PowerMEMS49317.2019.71805307288
M. Mariello, E. Scarpa, L. Algieri, F. Guido, V. Mastronardi, A. Qualtieri, M. Vittorio
This paper reports the fabrication and preliminary characterization of a novel flexible triboelectric nanogenerator (TENG) which could be employed for driving future low-consumption wearable devices. The single-electrode device operates in contact-separation mode and it is based on a combination of a polysiloxane elastomer and a poly(para-xylylene). In particular, a poly(dimethylsiloxane) (PDMS) substrate was made porous and rough with a steam-curing step; then, it was metallized and an optimal substrate-electrodes adhesion was achieved. Finally, the structure was coated with a thin film of Parylene-C serving as friction layer. This material provides excellent conformability and high charge retaining capability. Performance preliminary tests were conducted by measuring the open-circuit voltage and power density under finger tapping ($sim$2N) at $sim$5Hz. The device exhibited a peak-to-peak voltage of 1.51÷3.82V and the peak of power density was $2.24mW/m^{2}$ at $sim$0.4M $omega$.
{"title":"Mechanical energy harvesting through a novel flexible contact-separation mode triboelectric nanogenerator based on metallized porous PDMS and Parylene-C","authors":"M. Mariello, E. Scarpa, L. Algieri, F. Guido, V. Mastronardi, A. Qualtieri, M. Vittorio","doi":"10.1109/PowerMEMS49317.2019.71805307288","DOIUrl":"https://doi.org/10.1109/PowerMEMS49317.2019.71805307288","url":null,"abstract":"This paper reports the fabrication and preliminary characterization of a novel flexible triboelectric nanogenerator (TENG) which could be employed for driving future low-consumption wearable devices. The single-electrode device operates in contact-separation mode and it is based on a combination of a polysiloxane elastomer and a poly(para-xylylene). In particular, a poly(dimethylsiloxane) (PDMS) substrate was made porous and rough with a steam-curing step; then, it was metallized and an optimal substrate-electrodes adhesion was achieved. Finally, the structure was coated with a thin film of Parylene-C serving as friction layer. This material provides excellent conformability and high charge retaining capability. Performance preliminary tests were conducted by measuring the open-circuit voltage and power density under finger tapping ($sim$2N) at $sim$5Hz. The device exhibited a peak-to-peak voltage of 1.51÷3.82V and the peak of power density was $2.24mW/m^{2}$ at $sim$0.4M $omega$.","PeriodicalId":6648,"journal":{"name":"2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS)","volume":"1 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87281572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/PowerMEMS49317.2019.82063202439
M. Wagih, A. Weddell, S. Beeby
AbstractRadio Frequency Energy Harvesting and power transfer, using rectifying antennas, are increasingly seen as an enabling technology of power-autonomous devices. The non-linearity of the rectification element, the diode, adds challenges when experimentally characterizing and comparing the performance of different rectifiers, requiring complex measurement techniques to characterize a diode experimentally, and adds to the challenges of designing a matching network. This paper presents a method for characterizing the power conversion of a mismatched rectifier using a single-port vector network analyzer, omitting the need for impedance tuners and accurately reflecting the non-linearity of the diode. The proposed approach minimizes uncertainty sources in the test setup and shows close agreement with optimized harmonic balance simulation. Finally, harmonic balance simulation is utilized to compare the source and load impedance of the two most common rectifier topologies, a single series and a voltage doubler, acting as a guide for matching network and antenna design.
{"title":"Characterizing and Modelling Non-Linear Rectifiers for RF Energy Harvesting","authors":"M. Wagih, A. Weddell, S. Beeby","doi":"10.1109/PowerMEMS49317.2019.82063202439","DOIUrl":"https://doi.org/10.1109/PowerMEMS49317.2019.82063202439","url":null,"abstract":"AbstractRadio Frequency Energy Harvesting and power transfer, using rectifying antennas, are increasingly seen as an enabling technology of power-autonomous devices. The non-linearity of the rectification element, the diode, adds challenges when experimentally characterizing and comparing the performance of different rectifiers, requiring complex measurement techniques to characterize a diode experimentally, and adds to the challenges of designing a matching network. This paper presents a method for characterizing the power conversion of a mismatched rectifier using a single-port vector network analyzer, omitting the need for impedance tuners and accurately reflecting the non-linearity of the diode. The proposed approach minimizes uncertainty sources in the test setup and shows close agreement with optimized harmonic balance simulation. Finally, harmonic balance simulation is utilized to compare the source and load impedance of the two most common rectifier topologies, a single series and a voltage doubler, acting as a guide for matching network and antenna design.","PeriodicalId":6648,"journal":{"name":"2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS)","volume":"79 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88526584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/PowerMEMS49317.2019.92321107155
N. Panayanthatta, L. Montès, E. Bano, C. Trigona, R. L. Rosa
Piezoelectric energy harvesters (PEHs) have been regarded as a feasible solution for microwatt power generators as they produce sufficient power to drive low-power electronic devices such as smart wireless sensors nodes [1]. In ultra-low power applications, such as battery-free sensor nodes based on vibration energy harvesting, the level of power to be transferred is often so low that it is difficult to design a Maximum Power Point Tracking (MPPT) circuitry efficient enough to consider its implementation worthwhile [2]. A vibrating piezoelectric element can be considered as an AC source in parallel with its internal capacitance [2]. It then needs to be rectified at a desired DC voltage level before the harvested energy is stored. Therefore, it is necessary to design an energy efficient PEH circuit, minimizing the nonscalable losses in the circuitry, especially when dedicated to low-power applications. The currently available adaptive circuits that can operate independent of the piezoelectric parameters and device loads have certain limitations such as the requirement of a complex electronic interface, like a dedicated microprocessor and an analog-to-digital (A/D) converter [3], [4] which inevitably dissipate a large part of the harvested energy [5]. To make MPPT worthwhile in ultra-low power energy harvesting applications, a negligible portion of the harvested power has to be accounted for the implementation of these functions. Since this may represent a tough challenge for IC designers, we propose a three terminal piezoelectric energy harvester with one of the terminals exclusively dedicated to sense the open circuit voltage (Voc) of the PEH. This approach can be advantageous as long as the Voc sensing cell is designed with area occupancy negligible compared to the main harvester. From a system point of view this loss in power and the presence of an extra pin is compensated by various advantages including the simplification of the circuit architecture associated to MPPT functions (e.g. pre-regulation, sampling, series switch and logic) and the reduction of the power absorption. With this new concept of piezoelectric energy harvester, the power management IC can be greatly simplified to a simple ultra-low power comparator, used to compare the voltage provided by the main harvester with the voltage provided by the Voc sensing cell.
{"title":"Three terminal piezoelectric energy harvester based on novel MPPT design","authors":"N. Panayanthatta, L. Montès, E. Bano, C. Trigona, R. L. Rosa","doi":"10.1109/PowerMEMS49317.2019.92321107155","DOIUrl":"https://doi.org/10.1109/PowerMEMS49317.2019.92321107155","url":null,"abstract":"Piezoelectric energy harvesters (PEHs) have been regarded as a feasible solution for microwatt power generators as they produce sufficient power to drive low-power electronic devices such as smart wireless sensors nodes [1]. In ultra-low power applications, such as battery-free sensor nodes based on vibration energy harvesting, the level of power to be transferred is often so low that it is difficult to design a Maximum Power Point Tracking (MPPT) circuitry efficient enough to consider its implementation worthwhile [2]. A vibrating piezoelectric element can be considered as an AC source in parallel with its internal capacitance [2]. It then needs to be rectified at a desired DC voltage level before the harvested energy is stored. Therefore, it is necessary to design an energy efficient PEH circuit, minimizing the nonscalable losses in the circuitry, especially when dedicated to low-power applications. The currently available adaptive circuits that can operate independent of the piezoelectric parameters and device loads have certain limitations such as the requirement of a complex electronic interface, like a dedicated microprocessor and an analog-to-digital (A/D) converter [3], [4] which inevitably dissipate a large part of the harvested energy [5]. To make MPPT worthwhile in ultra-low power energy harvesting applications, a negligible portion of the harvested power has to be accounted for the implementation of these functions. Since this may represent a tough challenge for IC designers, we propose a three terminal piezoelectric energy harvester with one of the terminals exclusively dedicated to sense the open circuit voltage (Voc) of the PEH. This approach can be advantageous as long as the Voc sensing cell is designed with area occupancy negligible compared to the main harvester. From a system point of view this loss in power and the presence of an extra pin is compensated by various advantages including the simplification of the circuit architecture associated to MPPT functions (e.g. pre-regulation, sampling, series switch and logic) and the reduction of the power absorption. With this new concept of piezoelectric energy harvester, the power management IC can be greatly simplified to a simple ultra-low power comparator, used to compare the voltage provided by the main harvester with the voltage provided by the Voc sensing cell.","PeriodicalId":6648,"journal":{"name":"2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS)","volume":"151 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85375313","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/PowerMEMS49317.2019.51289500405
N. Jackson
Bistable energy harvesting devices using magnetic repulsive forces have demonstrated the capability of widening the bandwidth, but at the expense of decreasing power. This paper reports on experimental results combining repulsive and attractive magnetic force configurations on a PiezoMEMS cantilever device. The goal of the study was to determine if varying magnetic configuration could enhance power density while widening the bandwidth. The paper investigates both in-plane and out-of-plane magnetic configuration using an AlN-based PiezoMEMS device with an embedded powdered NdFeB magnet as the mass. Results for the out-of-plane configuration using combination of attractive and repulsive forces demonstrated a significant power increase from (0.56 $mu$ W to 0.93 $mu$ W) without significant loss in bandwidth compared to repulsive force configuration. Attractive force configuration demonstrated a significant increase in power (3.73 $mu$ W) but with significant bandwidth reduction. Thus, controlling magnetic polarization can be used to tailor the bandwidth and power density requirements.
{"title":"Bistable PiezoMEMS Energy Harvester with varying Magnetic Configurations","authors":"N. Jackson","doi":"10.1109/PowerMEMS49317.2019.51289500405","DOIUrl":"https://doi.org/10.1109/PowerMEMS49317.2019.51289500405","url":null,"abstract":"Bistable energy harvesting devices using magnetic repulsive forces have demonstrated the capability of widening the bandwidth, but at the expense of decreasing power. This paper reports on experimental results combining repulsive and attractive magnetic force configurations on a PiezoMEMS cantilever device. The goal of the study was to determine if varying magnetic configuration could enhance power density while widening the bandwidth. The paper investigates both in-plane and out-of-plane magnetic configuration using an AlN-based PiezoMEMS device with an embedded powdered NdFeB magnet as the mass. Results for the out-of-plane configuration using combination of attractive and repulsive forces demonstrated a significant power increase from (0.56 $mu$ W to 0.93 $mu$ W) without significant loss in bandwidth compared to repulsive force configuration. Attractive force configuration demonstrated a significant increase in power (3.73 $mu$ W) but with significant bandwidth reduction. Thus, controlling magnetic polarization can be used to tailor the bandwidth and power density requirements.","PeriodicalId":6648,"journal":{"name":"2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS)","volume":"1 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78124578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/PowerMEMS49317.2019.61547406204
Ioannis Nikiforidis, J. Arteaga, C. Kwan, D. Yates, P. Mitcheson
Class EF inverters have been widely used recently as primary coil drivers for wireless power transfer applications since they achieve constant output current across a range of link coupling factor values. As the operating frequency that the inductive link is tuned at increases the traditional circuit design techniques that are based on first order calculations fail to represent the inverter behaviour accurately. In this paper, we present a novel method of modelling Class EF inverters that is based on state space representation of the circuit and thus providing the highest accuracy possible. Our method consists of a combination of analytical and numerical calculations in such manner that any parasitic component of the circuit, such as the nonlinear output capacitance of a power switch, can be included in the tuning process.
{"title":"Design and Modelling of Class EF Inverters for Wireless Power Transfer Applications","authors":"Ioannis Nikiforidis, J. Arteaga, C. Kwan, D. Yates, P. Mitcheson","doi":"10.1109/PowerMEMS49317.2019.61547406204","DOIUrl":"https://doi.org/10.1109/PowerMEMS49317.2019.61547406204","url":null,"abstract":"Class EF inverters have been widely used recently as primary coil drivers for wireless power transfer applications since they achieve constant output current across a range of link coupling factor values. As the operating frequency that the inductive link is tuned at increases the traditional circuit design techniques that are based on first order calculations fail to represent the inverter behaviour accurately. In this paper, we present a novel method of modelling Class EF inverters that is based on state space representation of the circuit and thus providing the highest accuracy possible. Our method consists of a combination of analytical and numerical calculations in such manner that any parasitic component of the circuit, such as the nonlinear output capacitance of a power switch, can be included in the tuning process.","PeriodicalId":6648,"journal":{"name":"2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS)","volume":"41 1","pages":"1-4"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75995020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/powermems49317.2019.9080274
{"title":"PowerMEMS 2019 Table of Contents","authors":"","doi":"10.1109/powermems49317.2019.9080274","DOIUrl":"https://doi.org/10.1109/powermems49317.2019.9080274","url":null,"abstract":"","PeriodicalId":6648,"journal":{"name":"2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS)","volume":"141 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83538273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/PowerMEMS49317.2019.P5-11
S. Saini, A. Yonamine, R. Nishio, I. Matsumoto, T. Yabuki, K. Miyazaki
Thermoelectric effect can be a promising candidate as a sustainable energy source for internet of things devices. In this regards, thin films of organic-inorganic hybrid halide-perovskites, Methylamonium tin iodide, were fabricated by spin coating technique on a glass substrate. Thin films were structurally and chemically characterized by x-ray diffraction pattern and scanning electron microscope. Thermoelectric parameters were measured near room temperature. Thin films heated for 5 min at 100°C shows the best performance with electrical conductivity 2.4 S/cm, Seebeck coefficient $65 mu V/K$ and power factor of $1.0 mu W/m cdot K^{2}$. Thermoelectric performance from these hybrid-halide perovskite will help for further development of direct thermal energy harvesting devices near room temperature.
热电效应可以作为物联网设备的可持续能源。在此基础上，利用自旋镀膜技术在玻璃衬底上制备了有机-无机杂化卤化物-钙钛矿-碘化甲基铵锡薄膜。利用x射线衍射图和扫描电镜对薄膜进行了结构和化学表征。在室温附近测量热电参数。薄膜在100°C下加热5 min，电导率为2.4 S/cm，塞贝克系数为$65 mu V/K$，功率因数为$1.0 mu W/m cdot K^{2}$。这些混合卤化物钙钛矿的热电性能将有助于进一步开发室温下的直接热能收集装置。
{"title":"Hybrid-halide perovskite thin films for thermoelectric application","authors":"S. Saini, A. Yonamine, R. Nishio, I. Matsumoto, T. Yabuki, K. Miyazaki","doi":"10.1109/PowerMEMS49317.2019.P5-11","DOIUrl":"https://doi.org/10.1109/PowerMEMS49317.2019.P5-11","url":null,"abstract":"Thermoelectric effect can be a promising candidate as a sustainable energy source for internet of things devices. In this regards, thin films of organic-inorganic hybrid halide-perovskites, Methylamonium tin iodide, were fabricated by spin coating technique on a glass substrate. Thin films were structurally and chemically characterized by x-ray diffraction pattern and scanning electron microscope. Thermoelectric parameters were measured near room temperature. Thin films heated for 5 min at 100°C shows the best performance with electrical conductivity 2.4 S/cm, Seebeck coefficient $65 mu V/K$ and power factor of $1.0 mu W/m cdot K^{2}$. Thermoelectric performance from these hybrid-halide perovskite will help for further development of direct thermal energy harvesting devices near room temperature.","PeriodicalId":6648,"journal":{"name":"2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS)","volume":"40 1","pages":"1-3"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88702156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/PowerMEMS49317.2019.20515804804
N. Beigh, P. Azad, P. Parkash, D. Mallick
The practical applications of nonlinear, wideband Mechanical Energy Harvesting (MEH) devices are often restricted due to their inability to generate useable electrical energy at very low ambient mechanical vibrations. This is even more challenging for the MEMS-scale devices due to several practical constraints. Here, we propose three different topologies of MEMS buckled beam structures which can be used for low-frequency, nonlinear bistable energy harvesting. The tapered beam structure shows minimum potential energy barrier height which lowers the minimum threshold of the external mechanical excitations for initiating large amplitude oscillations. As an alternative, a suitable electrical energy injection method is also demonstrated for this purpose. The final, optimized designs could lead to high-performance, MEH applications when incorporated with a piezoelectric transducer.
{"title":"High Performance, Nonlinear Piezoelectric MEMS Energy Harvesting from Low-threshold Mechanical Vibrations","authors":"N. Beigh, P. Azad, P. Parkash, D. Mallick","doi":"10.1109/PowerMEMS49317.2019.20515804804","DOIUrl":"https://doi.org/10.1109/PowerMEMS49317.2019.20515804804","url":null,"abstract":"The practical applications of nonlinear, wideband Mechanical Energy Harvesting (MEH) devices are often restricted due to their inability to generate useable electrical energy at very low ambient mechanical vibrations. This is even more challenging for the MEMS-scale devices due to several practical constraints. Here, we propose three different topologies of MEMS buckled beam structures which can be used for low-frequency, nonlinear bistable energy harvesting. The tapered beam structure shows minimum potential energy barrier height which lowers the minimum threshold of the external mechanical excitations for initiating large amplitude oscillations. As an alternative, a suitable electrical energy injection method is also demonstrated for this purpose. The final, optimized designs could lead to high-performance, MEH applications when incorporated with a piezoelectric transducer.","PeriodicalId":6648,"journal":{"name":"2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS)","volume":"89 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80358098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/PowerMEMS49317.2019.51289501405
K. Kittipaisalsilpa, T. Kato, Y. Suzuki
In this report, the liquid-crystal-enhanced electret vibration energy harvester has been realized for the first time. The effect of impurities and humidity on resistivity of nematic liquid crystal (LC) was examined. By suppressing the ionic impurities and humidity absorption in the operation environment, extremely-high resistivity of $10^{16}Omega mathrm{c}mathrm{m}$ can be obtained. By introducing LC between the electrets/electrodes, 7-times higher output power compared to the air gap has been obtained for over 40 hours. Furthermore, the LC alignment near the electrode gap is also investigated with Fourier-transform infrared (FT-IR) spectrometry. The power generation model is proposed based on the present finding, and the simulation results agree well with the experimental data.
{"title":"Effect of Impurity/Humidity on Liquid-Crystal-Enhanced Electret Vibration Energy Harvester","authors":"K. Kittipaisalsilpa, T. Kato, Y. Suzuki","doi":"10.1109/PowerMEMS49317.2019.51289501405","DOIUrl":"https://doi.org/10.1109/PowerMEMS49317.2019.51289501405","url":null,"abstract":"In this report, the liquid-crystal-enhanced electret vibration energy harvester has been realized for the first time. The effect of impurities and humidity on resistivity of nematic liquid crystal (LC) was examined. By suppressing the ionic impurities and humidity absorption in the operation environment, extremely-high resistivity of $10^{16}Omega mathrm{c}mathrm{m}$ can be obtained. By introducing LC between the electrets/electrodes, 7-times higher output power compared to the air gap has been obtained for over 40 hours. Furthermore, the LC alignment near the electrode gap is also investigated with Fourier-transform infrared (FT-IR) spectrometry. The power generation model is proposed based on the present finding, and the simulation results agree well with the experimental data.","PeriodicalId":6648,"journal":{"name":"2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS)","volume":"4 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91240150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-12-01DOI: 10.1109/PowerMEMS49317.2019.30773705679
M. Zhang, J. Shi, S. Beeby
Charge dissipation in previous Polydimethylsiloxane (PDMS) ferroelectrets was observed and the piezoelectric coefficient d33 of most samples drop to below 10 pC/N in one month after charging. This issue limits its long-term energy harvesting performance. This paper presents an approach to coat the PDMS with Polytetrafluoroethylene (PTFE) to enhance the surface charge stability of the ferroelectret. After coating a thin PTFE film in the void surfaces of PDMS ferroelectret, the piezoelectric coefficient d33 obtained remained at 80 pC/N after 6 months.
{"title":"Improved charge stability in PTFE coatings for PDMS ferroelectrets","authors":"M. Zhang, J. Shi, S. Beeby","doi":"10.1109/PowerMEMS49317.2019.30773705679","DOIUrl":"https://doi.org/10.1109/PowerMEMS49317.2019.30773705679","url":null,"abstract":"Charge dissipation in previous Polydimethylsiloxane (PDMS) ferroelectrets was observed and the piezoelectric coefficient d33 of most samples drop to below 10 pC/N in one month after charging. This issue limits its long-term energy harvesting performance. This paper presents an approach to coat the PDMS with Polytetrafluoroethylene (PTFE) to enhance the surface charge stability of the ferroelectret. After coating a thin PTFE film in the void surfaces of PDMS ferroelectret, the piezoelectric coefficient d33 obtained remained at 80 pC/N after 6 months.","PeriodicalId":6648,"journal":{"name":"2019 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (PowerMEMS)","volume":"227 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85157811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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