Dissertations / Theses: 'Nanogenerator'

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Van, den Heever Thomas Stanley. "Development and optimisation of a zinc oxide nanowire nanogenerator." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85781.

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Thesis (PhD)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: This study developed and optimised zinc oxide (ZnO) nanowire-based nanogenerator. The nanogenerator works on the piezoelectric effect that is, a mechanical force is converted to an electrical voltage. The ZnO nanowires are piezoelectric and when any force is applied to the nanowires an output voltage is generated. This ZnO nanowire-based nanogenerator can be used to power small electronic devices, such as pacemakers. The nanogenerator can also be incorporated into clothes and shoes to generate electricity to charge a cell phone for example. The problem experienced currently is that the nanogenerator does not generate enough electricity to be of practical use and needs to be further optimised. Simulations and mathematical models were used to identify areas where the nanogenerator could be optimised in order to increase the output voltage. It is shown that the morphology of the nanowires can have a considerable effect on the output voltage. For this reason the growth of the nanowires was investigated first. Different methods were used to propagate the nanowires in order to select the method that, on average, has the highest output voltage. Accordingly, one parameter at a time and design of experiments were used to optimise the nanowire growth. Consequently, these two methods were used to optimise the growth parameters with the respect to the output voltage. The aqueous solution method was found to yield nanowires that give the highest generated output voltage. After growing over 600 nanowire samples, optimal growth parameters for this method were found. These optimal growth parameters were subsequently used to grow nanowires that were used to manufacture the nanogenerator. The nanowires were grown on a solid substrate and hence the nanogenerator was also manufactured on the solid substrate. Through various optimisations of the manufacturing process the maximum output voltage achieved was about 500 mV. However, this output voltage is too low to be of practical use, even though the output has been raised considerably. The main problem was found to be the fact that the contact between the nanowires and the electrode was weak due to contamination. A new method was therefore required where the electrode and the nanowires would be in proper contact to ensure that higher output voltages were achieved. Subsequently, a flexible nanogenerator was manufactured in order to solve this problem. Accordingly, the nanowires were grown on the flexible polyimide film and a buffer layer was then spun onto the flexible substrate, leaving only the nanowire tips exposed. The electrode was then sputtered on top of this buffer layer, covering the nanowire tips. This ensured proper contact between the nanowires and the electrode. The nanogenerator, which was manufactured with non-optimal growth parameters, gives a maximum voltage output of 1 V, double the maximum achieved with the solid nanogenerator. When the optimal growth parameters were used the output voltage was raised to 2 V. Various optimisation techniques were performed on the nanogenerator, including plasma treatment and annealing and the use of various materials in the buffer layer. Combining these optimisation methods subsequently led to an optimised nanogenerator that can generate an output voltage of over 5 V. This was achieved after over 1200 nanogenerators had been manufactured. However, the output voltage was not in a usable form. Circuitry was therefore developed to transform the voltage generated by the nanogenerator to a useable form. The best circuit, the LTC3588, was used to power an LED for 10 seconds. The completed device was found to achieve a power output of 0.3 mW, enough for small electronic devices.
AFRIKAANSE OPSOMMING: ‘n Sink-oksied (ZnO) nanodraad gebaseerde nanogenerator is ontwikkeld en geöptimeer. Die nanogenerator werk met behulp van die piezoelektriese effek - meganiese krag work omgesit in ‘n elektriese spanning. Die ZnO nanodrade is piezoelektries en wanneer ‘n krag op die drade aangewend word, word ‘n uittree spanning gegenereer. Die nanogenerator kan gebruik word om klein elektroniese toestelle, soos ‘n pasaangeër, van krag te voorsien. Die nanogenerator kan in klere en skoene geïnkorporeer word om elektrisiteit op te wek vir die laai van ‘n selfoon. Die probleem is egter dat die nanogenerator tans nie genoeg krag opwek om prakties van nut te wees nie en verdere optimasie word benodig. Simulasies en wikundige modelle work gebruik om areas te identifiseer waar die nanogenerator geöptimeer kan word, met die doel om die uittreespanning te verhoog. Dit word bewys dat die morfologie van die nanodrade ‘n groot effek het op die uittreespanning. Dus word die groei van die nanodrade eerste ondersoek. Verskillende metodes word gebruik om die nanodrade te groei en die beste metode, wat die hoogste uittreespanning op gemiddeld verskaf, word gekies. Een parameter op ‘n slag en ontwerp van eksperimente word gebruik om die nanodraad groei te optimeer. Die groei parameters word geöptimeer deur van die twee metodes gebruik te maak, en die optimeering word gedoen in terme van die uittreespanning. Die oplossing groei metode lei tot nanodrade wat die hoogste uittreespanning verskaf. Na oor die 600 nanodraad monsters gegroei is, is die optimale parameters gevind. Hierdie optimale parameters word uitsluitlik gebruik om die nanogenerator te vervaardig. Die nanodrade word op ‘n soliede substraat gegroei en dus word die nanogenerator op dieselfde soliede substraat vervaardig. Verskeie metodes is gebruik om die vervaardiging te optimeer en die hoogste uittreespanning wat bereik is, is 500 mV. Die uittreespanning is te laag om van praktiese nut te wees alhoewel dit heelwat verhoog is. Die grootste probleem is die swak kontak tussen die nanodrade en die elektrode, wat veroorsaak word deur kontaminasie. ‘n Nuwe metode word verlang wat beter kontak tussen die nanodrade en elektrode sal verseker. ‘n Buigbare nanogenerator is vervaardig om die probleem op te los. Die nanodrade word nou op ‘n buigbare film gegroei. ‘n Bufferlaag word tussen die nanodrade in gedraai, tot net die punte van die nanodrade nog sigbaar is. Die elektrode word bo-op die bufferlaag gedeponeer, wat behoorlike kontak tussen die nanodrade en elektrode verseker. Die nanogenerator wat met nie-optimale groei parameters vervaardig is, bereik ‘n uittreespanning van 1 V, dubbel die soliede nanogenerator. Met optimale groei parameters word die uittreespanning tot 2 V verhoog. Verskeie optimasie tegnieke word op die nanogenerator toegepas. Die metodes sluit in suurstof plasma behandeling, verhitting en die inkorporasie van verskillende materiale in die bufferlaag. ‘n Kombinasie van die metodes geïnkorporeer in een nanogenerator lei tot ‘n uittreespanning van 5 V. Die uittreespanning is bereik na oor die 1200 nanogenerators vervaardig is. The uittreespanning is nog nie in ‘n bruikbare vorm nie. Spesiale stroombane is ontwikkel wat die nanogenerator spanning omskakel na ‘n bruikbare vorm. Die beste stroombaan, die LTC3588, kan ‘n LED aanskakel vir 10 sekondes. The toestel kan ook 0.3mWuittreekrag voorsien, genoeg vir klein elektroniese toestelle om te werk.

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Dönmez, Noyan Inci. "Improving the performance of an all-Si based thermoelectric micro/nanogenerator." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/650830.

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Esta tesis presenta el desarrollo de un microgenerador termoeléctrico (μTEG) con el objetivo de alimentar nodos sensores inalámbricos de bajo consumo para aplicaciones en la Internet de las Cosas. El μTEG propuesto se ha fabricado mediante tecnologías de micromecanizado de silicio y haciendo uso de formaciones de nanohilos de silicio (Si) y de silicio/germanio (SiGe) como material termoeléctrico. Se han definido rutas tecnológicas de fabricación adecuadas para aumentar la densidad de potencia del μTEG. En particular, esta tesis se ha centrado en aumentar dicha potencia a partir de i) la optimización térmica y eléctrica de la microplataforma termoeléctrica, y ii) integrando un intercambiador de calor en los μTEGs propuestos. Las prestaciones térmicas del μTEG se han mejorado reduciendo las pérdidas parásitas de calor entre las partes calientes y frías de la microplataforma, lo que ha resultado en una reducción del 34% en la conductancia térmica. Las prestaciones eléctricas, por otro lado, han mejorado aún más importantemente al reducir la resistencia interna del dispositivo entre 7 y 20 veces. Ambos logros se han conseguido mediante el rediseño de la arquitectura y de algunos de los procesos de fabricación del μTEG. Aunque las densidades de potencia obtenidas para los μTEG optimizados se acercan a las necesidades de nodos sensores de bajo consumo (10-100 μW/cm2), se ha intentado mejorar su comportamiento mediante la integración de un intercambiador de calor. Para dicha integración se han ensayado dos rutas diferentes, en función de la dirección del flujo de calor en el dispositivo. En cualquier caso, se ha podido observar un incremento significativo de prestaciones para todos los μTEGs considerados (Si NWs, SiGe NWs y Si microbeams). Los μTEGs con intercambiador de calor integrado han sido capaces de colectar densidades de potencia de 41.2 (Si NWs), 45.2 (SiGe NWs) and 34.5 μW/cm2 (Si microbeams) cuando se han dispuesto sobre placas calientes a 100 ◦C de temperatura. Esto supone un incremento de 50-1000 veces con respecto a dispositivos similares sin el intercambiador de calor en esas mismas condiciones. Los resultados obtenidos en esta tesis están bien posicionados en relación al estado del arte de μTEGs. Además, esta tesis, junto con otra también llevada a cabo en colaboración con el IREC, reportan por primera vez μTEGs basados en nanohilos de SiGe.
This thesis presents the development of a thermoelectric microgenerator (μTEG) with the aim of powering low power wireless sensor nodes for Internet of Things applications. The proposed μTEG is fabricated by means of silicon micromachining technologies and makes use of silicon (Si) and silicon/germanium (SiGe) nanowire (NW) arrays as thermoelectric material. Specific technological routes are designed to increase the power density of the μTEG. Particularly, this thesis has been focused on increasing the power density through i) thermal and electrical optimization of the thermoelectric microplatform, ii) integration of a heat exchanger on the proposed μTEGs. The thermal performance of the μTEG is enhanced by reducing the parasitic thermal losses between the hot and cold ends which ended up in %34 decrease of the thermal conductance. The electrical performance, on the other hand is improved tremendously by lowering the device internal resistance 7 to 20 times. Both has been achieved through the redesign of the architecture and processing steps for μTEG. Even though the power densities obtained from the optimized μTEGs are close to meet the expectations for low power sensor nodes (10-100 μW/cm2), further improvement is aimed by the integration of a heat exchanger. Two different routes with different heat flow directions have been designed for the integration of a heat exchanger. With the integration of the heat exchanger, a significant amount of improvement has been observed for all tested μTEGs based on different thermoelectric materials (Si NWs, SiGe NWs and Si microbeams). μTEGs with integrated heat exchanger were able to harvest 41.2 (Si NWs), 45.2 (SiGe NWs) and 34.5 μW/cm2 (Si microbeams) when they were placed on a waste heat source of 100 ◦C. This is 50-1000 times more than for similar devices without heat exchanger at the same hot plate temperature. Results obtained in this thesis are well positioned compared with the state-of-the-art μTEGs. In addition, this thesis, together with the one performed in collaboration at IREC, reports for first time on the performance of SiGe NWs based μTEG.

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Wang, Sihong. "Nanogenerator for mechanical energy harvesting and its hybridization with li-ion battery." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53437.

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Energy harvesting and energy storage are two most important technologies in today's green and renewable energy science. As for energy harvesting, the fundamental science and practically applicable technologies are not only essential in realizing the self-powered electronic devices and systems, but also tremendously helpful in meeting the rapid-growing world-wide energy consumptions. Mechanical energy is one of the most universally-existing, diversely-presenting, but usually-wasted energies in the natural environment. Owing to the limitations of the traditional technologies for mechanical energy harvesting, it is highly desirable to develop new technology that can efficiently convert different types of mechanical energy into electricity. On the other hand, the electricity generated from environmental energy often needs to be stored before used to drive electronic devices. For the energy storage units such as Li-ion batteries as the power sources, the limited lifetime is the prominent problem. Hybridizing energy harvesting devices with energy storage units could not only provide new solution for this, but also lead to the realization of sustainable power sources. In this dissertation, the research efforts have led to several critical advances in a new technology for mechanical energy harvesting—triboelectric nanogenerators (TENGs). Previous to the research of this dissertation, the TENG only has one basic mode—the contact mode. Through rational structural design, we largely improved the output performance of the contact-mode TENG and systematically studied their characteristics as a power source. Beyond this, we have also established the second basic mode for TENG—the lateral sliding mode, and demonstrated sliding-based disk TENGs for harvesting rotational energy and wind-cup-based TENGs for harvesting wind energy. In order to expand the application and versatility of TENG by avoid the connection of the electrode on the moving part, we further developed another basic mode—freestanding-layer mode, which is capable of working with supreme stability in non-contact mode and harvesting energy from any free-moving object. Both the grating structured and disk-structured TENGs based on this mode also display much improved long-term stability and very high energy conversion efficiency. For the further improvement of the TENG’s output performance from the material aspect, we introduced the ion-injection method to study the maximum surface charge density of the TENG, and for the first time unraveled its dependence on the structural parameter—the thickness of the dielectric film. The above researches have largely propelled the development of TENGs for mechanical energy harvesting and brought a big potential of impacting people’s everyday life. Targeted at developing sustainable and independent power sources for electronic devices, efforts have been made in this dissertation to develop new fundamental science and new devices that hybridize the nanogenerator-based mechanical energy harvesting and the Li-ion-battery-based energy storage process into a single-step process or in a single device. Through hybridizing a piezoelectric nanogenerator with a Li-ion battery, a self-charging power cell has been demonstrated based on a fundamentally-new mechanical-to-electrochemcial process. The triboelectric nanogenerator as a powerful technology for mechanical energy harvesting has also been hybridized with a Li-ion battery into a self-charging power unit. This new concept of device can sustainably provide a constant voltage for the non-stop operation of electronic devices.

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Dhakras, D. "Novel flexible device platforms using electrospinning process for sensor and nanogenerator applications." Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2015. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2254.

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Song, Jinhui. "Nanogenerators." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24772.

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Thesis (Ph.D.)--Materials Science and Engineering, Georgia Institute of Technology, 2008.
Committee Chair: Zhong lin Wang; Committee Member: Christopher J. Summers; Committee Member: Kenneth A. Gall; Committee Member: Robert L. Snyder; Committee Member: Russell D. Dupuis.

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Pradel, Ken Charles. "Antimony doped p-type zinc oxide for piezotronics and optoelectronics." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54386.

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Zinc oxide is a semiconducting material that has received lot of attention due to its numerous proeprties such as wide direct band gap, piezoelectricity, and numerous low cost and robust methods of synthesizing nanomaterials. Its piezoelectric properties have been harnessed for use in energy production through nanogenerators, and to tune carrier transport, birthing a field known as piezotronics. However, one weakness of ZnO is that it is notoriously difficult to dope p-type. Antimony was investigated as a p-type dopant for ZnO, and found to have a stability of up to 3 years, which is completely unprecedented in the literature. Furthermore, a variety of zinc oxide structures ranging from ultra-long nanowires to thin films were produced and their piezotronic properties were demonstrated. By making p-n homojunctions using doped and undoped ZnO, enhanced nanogenerators were produced which could see application in gesture recognition. As a proof of concept, a simple photodetector was also derived from a core-shell nanowire structure. Finally, the ability to integrate this material with other semiconductors was demonstrated by growing a heterojunction with silicon nanowires, and investigating its electrical properties. All this work together lays the foundation for a fundamentally new material that could see application in future electronics, optoelectronics, and human-machine interfacing.

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Armas, Jeremy A. "Influence of High Aspect Ratio Nanoparticle Filler Addition on Piezoelectric Nanocomposites." DigitalCommons@CalPoly, 2018. https://digitalcommons.calpoly.edu/theses/2026.

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Piezoelectric nanogenerators (PNGs) are a new class of energy harvesting materials that show potential as a direct energy source for low powered electronics. Recently, piezoelectric polymers have been utilized for PNG technology due to low toxicity, high flexibility, and facile solution processing which provide manufacturing opportunities such as screen printing. Throughout the last decade, countless projects have focused on how to enhance the energy harvesting capabilities of these PNGs through the incorporation of nanoparticle fillers, which have been reported to enhance the piezoelectric properties of the film either directly through their intrinsic piezoelectric properties or through acting as surfaces for the interfacial nucleation of piezoelectric polymer crystals. Herein, two systems of PNGs formed from piezoelectric copolymers poly(vinylidene fluoride-co-hexafluropropylene) or poly(vinylidene fluoride-co-trifluoroethylene) mixed with high aspect ratio zinc oxide nanowires, hydroxyl functionalized multi-walled carbon nanotubes, or carboxylic acid functionalized single walled carbon nanotubes were investigated. Variations of filler type and loading are tested to determine influences on film morphology and piezoelectric properties. Power harvesting tests are conducted to directly determine the effect of nanoparticle addition on the output power of the non-poled devices. Both copolymer systems are found to exhibit a non-linear increase in output power with the increase of nanoparticle filler loading. The crystal polymorph properties of both systems are investigated by Fourier transform infrared spectroscopy. The microstructure of the poly(vinylidene fluoride-co-trifluoroethylene) films are further examined using X-ray diffraction, differential scanning calorimetry, polarized optical microscopy, and atomic force microscopy to determine the mechanism behind the increased power harvesting capabilities. As well, explanations for perceived output power from “self-poled” films are briefly explored.

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Satti, Nour Eiman. "Development of Zinc Oxide Piezoelectric Nanogenerators for Low Frequency Applications." Doctoral thesis, Linköpings universitet, Institutionen för teknik och naturvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-131858.

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Energy harvesting using piezoelectric nanomaterials provides an opportunity for advancement towards self-powered systems. Self-powered systems are a new emerging technology, which allows the use of a system or a device that perform a function without the need for external power source like for example, a battery or any other type of source. This technology can for example use harvested energy from sources around us such as ambient mechanical vibrations, noise, and human movement, etc. and convert it to electric energy using the piezoelectric effect. For nanoscale devices, the size of traditional batteries is not suitable and will lead to loss of the concept of “nano”. This is due to the large size and the relatively large magnitude of the delivered power from traditional sources. The development of a nanogenerator (NG) to convert energy from the environment into electric energy would facilitate the development of some self-powered systems relying on nano- devices. The main objective of this thesis is to fabricate a piezoelectric Zinc Oxide (ZnO) NGs for low frequency (˂ 100 Hz) energy harvesting applications. For that, different types of NGs based on ZnO nanostructures have been carefully developed, and studied for testing under different kinds of low frequency mechanical deformations. Well aligned ZnO nanowires (NWs) possessing high piezoelectric coefficient were synthesized on flexible substrates using the low temperature hydrothermal route. These ZnO NWs were then used in different configurations to demonstrate different low frequency energy harvesting devices. Using piezoelectric ZnO NWs, we started with the fabrication of sandwiched NG for hand writing enabled energy harvesting device based on a thin silver layer coated paper substrate. Such device configurations can be used for the development of electronic programmable smart paper. Further, we developed this NG to work as a triggered sensor for wireless system using foot-step pressure. These studies demonstrate the feasibility of using ZnO NWs piezoelectric NG as a low-frequency self-powered sensor, with potential applications in wireless sensor networks. After that, we investigated and fabricated a sensor on PEDOT: PSS plastic substrate either by one side growth technique or by using double sided growth. For the first growth technique, the fabricated NG has been used as a sensor for acceleration system; while the fabricated NG by the second technique has worked as anisotropic directional sensor. This fabricated configurations showed stability for sensing and can be used in surveillance, security, and auto-mobil applications. In addition to that, we investigated the fabrication of a sandwiched NG on plastic substrates. Finally, we demonstrated that doping ZnO NWs with extrinsic element (such as Ag) will lead to the reduction of the piezoelectric effect due to the loss of crystal symmetry. A brief summary into future opportunities and challenges are also presented in the last chapter of this thesis.

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Feng, Ziang. "Wearable Power Sources and Self-powered Sensors Based on the Triboelectric Nanogenerators." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/103020.

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The triboelectric nanogenerator (TENG) has attracted global attention in the fields of power sources and self-powered sensors. By coupling the omnipresent triboelectrification effect and the electrical induction effect, the TENGs can transduce ambient mechanical energy into electrical energy. Such energy could be consumed instantaneously or stored for later use. In this way, they could be deployed distributedly to be compatible power sources in the era of the internet of things (IoTs), completing the powering structure that is currently relying on power plants. Also, the electrical signals can reflect the environment changes around the TENGs. Thus, the TENGs can serve as self-powered sensors in the IoTs. In this work, we adopted two approaches for TENG fabrication: the thermal drawing method (TDP) and 3D printing. With TDP, we have fabricated scalable fiber-based triboelectric nanogenerators (FTENG), which have been woven into textiles by an industrial loom for wearable use. This fabrication process can supply FTENG on a large scale and fast speed, bridging the gap between the TENG and weaving industry. With 3D printing, we have fabricated TENGs that are compatible with the shape of arbitrary substrates. They have been used as biocompatible sensors: human-skin-compatible TENG has been used to recognize silent speech in real-time by sensing the chin movement; the porcine-kidney-shaped fiber mesh has been used to monitor the perfusion rate of the organ. These works have extended the territory of TENGs and can be critical components in the IoTs.
Ph.D.
Portable electronic devices have become important components in our daily lives, and we are entering the era of the Internet of Things (IoTs), where everyday objects can be interconnected by the internet. While electricity is essential to all of these devices, the traditional power sources are commonly heavy and bulky and need to be recharged or directly connected to the immobile power plants. Researchers have been working to address this mismatch between the device and power systems. The triboelectric nanogenerators (TENG) are good candidates because they can harvest energy in the ambient environment. The users can use them to generate electricity by merely making the rubbing motion. In this work, we report two fabrication methods of the fiber-based triboelectric nanogenerators (FTENG). With the thermal drawing process, we have fabricated sub-kilometer-long FTENG and wove it with the regular cotton yarn into textiles. The wearable power source is human friendly as it does not induce any extra weight load for the user. Besides, we have demonstrated that such long fibers can work as self-powered distributed sensors, such as a Morse code generator. With 3D printing, we have fabricated FTENG-based devices that conform to the working substrates, which can be any shape. We have employed them as biofriendly sensors to translate the chin movement during speaking to language and to monitor the perfusion rate of a pig kidney. The FTENGs have offered excellent comfortability to the users and can play a vital role in reframing the power structure to be compatible with IoTs.

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Chen, Jun. "Triboelectric nanogenerators." Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54956.

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With the threatening of global warming and energy crises, searching for renewable and green energy resources with reduced carbon emissions is one of the most urgent challenges to the sustainable development of human civilization. In the past decades, increasing research efforts have been committed to seek for clean and renewable energy sources as well as to develop renewable energy technologies. Mechanical motion ubiquitously exists in ambient environment and people’s daily life. In recent years, it becomes an attractive target for energy harvesting as a promising supplement to traditional fuel sources and a potentially alternative power source to battery-operated electronics. Until recently, the mechanisms of mechanical energy harvesting are limited to transductions based on piezoelectric effect, electromagnetic effect, electrostatic effect and magnetostrictive effect. Widespread usage of these techniques is likely to be shadowed by possible limitations, such as structure complexity, low power output, fabrication of high-quality materials, reliance on external power sources and little adaptability on structural design for different applications. In 2012, triboelectric nanogenerator (TENG), a creative invention for harvesting ambient mechanical energy based on the coupling between triboelectric effect and electrostatic effect has been launched as a new and renewable energy technology. The concept and design presented in this thesis research can greatly promote the development of TENG as both sustainable power sources and self-powered active sensors. And it will greatly help to define the TENG as a fundamentally new green energy technology, featured as being simple, reliable, cost-effective as well as high efficiency.

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Serairi, Linda. "Elaboration et conception des dispositifs de la récupération d’énergie à base de nanofils de ZnO et de microfibres de PVDF-TrFE." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1189/document.

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Le développement des énergies renouvelables peut non seulement compenser le manque d'énergie fossile à l'avenir, mais aussi sauver notre planète en réduisant la pollution par les émissions de CO2. Les matériaux piézoélectriques ont la capacité de convertir les mouvements mécaniques environnementaux en énergie électrique. Dans le cadre de cette thèse, deux types de matériaux piézoélectriques ont été étudiés pour la récupération d’énergie : les nanofils de ZnO et les microfibres de PVDF-TrFE. L’objectif ultime de cette thèse est de réaliser les dispositifs de la récupération d’énergie à faible coût pour rendre les capteurs autonomes.Au cours de la dernière décennie, les nanofils de ZnO ont suscité un grand intérêt dans le domaine de la recherche en raison de leurs multifonctionnalités avec un grand potentiel d’applications dans les différents domaines (récupération d’énergie par effet piézoélectrique et photovoltaïque, capteurs biologiques & chimiques, dépollution de l’eau & de l’air par effet photocatalytique, …). Le PVDF-TrFE est un polymère attrayant dans les applications de la récupération d'énergie en raison de ses propriétés piézoélectriques, son faible coût et sa grande flexibilité mécanique.Dans ce travail, deux méthodes de synthèse ont été employées pour obtenir les micro- & nanomatériaux piézoélectriques : Hydrothermale pour les réseaux verticaux des nanofils de ZnO et Electrospinning pour les microfibres de PVDF-TrFE. Les conditions de synthèse ont été optimisées afin d’obtenir les échantillons adéquats aux applications envisagées. Ensuite, deux types de dispositifs de la récupération d’énergie ont été fabriqués. Dans un premier temps, nous avons conçu des microgénérateurs (MGs) à base des microfibres de PVDF-TrFE déposées sur le substrat Kapton. Ces MGs flexibles basés sur l’effet piézoélectrique direct permettant la conversion de l’énergie mécanique en énergie électrique à basse fréquence de l’ordre d’hertz. Le second type de nanogénérateurs (NGs) est basé sur des nanofils verticaux de ZnO sur le substrat en silicium. Les tests de la récupération d’énergie ont été réalisés dans une gamme de fréquences de quelques centaines d’hertz pour l’application aéronautique
Development of renewable energy can not only compensate for the lack of fossil energy in the future, but also save our planet by reducing CO2 emission pollution. Piezoelectric materials have the ability to convert environmental mechanical movements into electrical energy. In this thesis, two types of piezoelectric materials have been studied for energy harvesting: ZnO nanowires and PVDF-TrFE microfibers. The ultimate goal of this thesis is to realize the low cost energy harvesting devices for self-powered sensors.Over the past decade, ZnO nanowires had attracted a great interest in the research field due to their multifunctionality with a great potential in the various applications (energy harvesting by piezoelectric and photovoltaic effect, bio & chemical sensors, water & air purification by photocatalytic effect ...). PVDF-TrFE is also an attractive polymer in energy harvesting due to its piezoelectric properties, high mechanical flexibility, and also for its low cost.In this work, two synthesis methods have been used to obtain the piezoelectric micro- & nanomaterials: Hydrothermal for the ZnO nanowire arrays and Electrospinning for the PVDF-TrFE microfibers. The synthesis conditions have been optimized in order to obtain the suitable samples for the applications. Then, two types of energy harvesting devices were manufactured. First, we realized the microgenerators (MGs) based on the PVDF-TrFE microfibers deposited on the Kapton substrate. These flexible MGs based on the direct piezoelectric effect allowing the conversion of mechanical energy into electrical energy at low frequency of the order of hertz. The second type of nanogenerators (NGs) is based on ZnO nanowire array on the silicon substrate. The energy harvesting tests were carried out in a frequency range of a few hundred hertz for the aeronautical application

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Zhu, Guang. "Nanogenerators for self-powered applications." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/51731.

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We are surrounded by enormous amounts of ambient mechanical energy that goes to waste such as rain drops, human footfalls, air flow, ocean waves, just to name a few. If such otherwise wasted mechanical energy can be effective converted into electricity, self-powered electronics are very likely to be realized, which can address the limitations of traditional power supplies in many cases, such as wireless sensor networks. Here in this work, two types of energy-harvesting nanogenerators (NGs) based were studied. For piezoelectric nanogenerators, zinc oxide (ZnO) nanowires (NWs) were used as building blocks to develop integrated NGs based on a number of ZnO NWs instead of a single NW. Two types of integrated NGs were developed, which consist of lateral NW arrays and vertical NW arrays. The electric output power was substantially enhanced compared to the design with a single NW. For triboelectric nanogenerators, triboelectric effect was innovatively used as an effective means of harvesting mechanical energy. The operating principle can be explained by the coupling between triboelectric and electrostatic effect. Two types of operating modes were invented, i.e. contact mode and sliding mode. Triggered by commonly available ambient mechanical energy such as footfalls, the maximum output power reached up to 1.2 W. More importantly, self-powered systems were built by using the NG as a power source. It can provide real time power for up to 600 commercial LED bulbs. This research not only provides the fundamentals for NGs but also demonstrates the practicability of using the self-powered technology in our daily life.

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Vargas, Estevez Carolina. "Suspended Micro/nanogenerators for cell stimulation." Doctoral thesis, Universitat de Barcelona, 2019. http://hdl.handle.net/10803/666193.

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Our bodies are complex machines whose functioning depends on multiple electrical signals controlled mainly by the nervous system. Afterwards, it is not illogical to think that one day artificial electrical impulses would replace those signals offering supports of medical treatments. Nowadays electrical stimulation is used in many therapeutic applications to modulate cellular activity, restore biological lost functions or even improve the performance of certain tissues. However, these systems still carry side effects link to the surgical interventions to place them or place their electrodes, their inherent bulkiness or lack in specificity to target only the cells involved in the condition to treat. The future to transcend these constrains would be possible in the extent that technology ease the path to improve precision, autonomy and miniaturization of the actual therapeutic tools. In this context, micro- and nanogenerators play a key role as self-powered devices with high spatial resolution and acute cell specificity. This thesis aims to provide micro/nanogenerators to stimulate single cells in its own liquid media. This work explored two technological branches based on photovoltaic and on magnetoelastic (piezoelectric/magnetostrictive) devices to harvest energy. Their fabrication was accomplished through semiconductors microfabrication technologies and their performance was characterized through several tests to ensure their correct power generation. As these devices were intended to interface biological media, direct cytotoxicity studies were conducted to guarantee their safety. Both branches were biologically validated with in vitro models of excitable cells (embryonic mouse neurons and human osteoblast- like cells) analyzing the electrostimulation effects through morphological changes and through instantaneous ionic responses as calcium signaling. The results gathered in this research demonstrated the feasibility of these micro- and nanogenerators as self-powered electrical stimulators. Furthermore, their reduce size and capability to be suspended in liquid media open the door to further developments towards injected or ingested minimally invasive medical tools.
Nuestros cuerpos son máquinas complejas cuyo funcionamiento depende de múltiples señales eléctricas controladas principalmente por el sistema nervioso. Así pues, no es ilógico pensar que un día los impulsos eléctricos artificiales reemplazarían aquellas señales dando soporte a los tratamientos médicos. En la actualidad, la estimulación eléctrica se utiliza en muchas aplicaciones terapéuticas para modular la actividad celular, restaurar funciones biológicas perdidas o incluso mejorar el rendimiento de ciertos tejidos. Sin embargo, estos sistemas aún presentan efectos secundarios ligados a las intervenciones quirúrgicas para colocarlos o colocar sus electrodos, a su volumen intrínseco o a la falta de especificidad para solo focalizar su actividad sobre las células involucradas en la enfermedad a tratar. El futuro para trascender estas limitaciones será posible en la medida en que la tecnología facilite el camino para mejorar la precisión, la autonomía y la miniaturización de las actuales herramientas terapéuticas. En este contexto, los micro/nanogeneradores juegan un papel clave como dispositivos autoalimentados con alta resolución especial y especificidad celular fina. Esta tesis pretende proporcionar micro/nanogeneradores de energía para estimular eléctricamente células individuales en su propio medio líquido. Este trabajo exploró dos ramas tecnológicas basadas en dispositivos fotovoltaicos y magnetoelásticos (piezoeléctricos / magnetoestrictivos) para transducir energía. Su fabricación se llevó a cabo a través de tecnologías de microfabricación de semiconductores y su rendimiento se caracterizó a través de varias pruebas para garantizar su correcta generación de energía. Como estos dispositivos estaban destinados a interconectar medios biológicos, se realizaron estudios de citotoxicidad directa para garantizar su seguridad. Ambas ramas se validaron biológicamente con modelos in vitro de células excitables (neuronas embrionarias de ratón y células de tipo óseo humanas) analizando los efectos de la electroestimulación a través de cambios morfológicos y a través de respuestas iónicas instantáneas como la señalización de calcio. Los resultados reunidos en esta investigación demostraron la viabilidad de estos micro/nanogeneradores como estimuladores eléctricos autoalimentados. Además, su reducido tamaño y la capacidad de estar en suspensión en medios líquidos abren la puerta a nuevos desarrollos hacia herramientas médicas mínimamente invasivas inyectadas o ingeridas.

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Niu, Simiao. "Theory of triboelectric nanogenerators for self-powered systems." Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54954.

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Energy science is becoming an increasingly important multi-disciplinary area, for not only addressing the worldwide energy crisis, but also realizing desired power sources with advanced features for portable electronic devices and sensor networks. Very recently, based on triboelectric effect and electrostatic induction, a fundamentally new technology, triboelectric nanogenerator, has been demonstrated which shows unique merits. But so far, the main limitation for continuing optimizing their output performance is a lack of fundamental understanding of their core working mechanism. In this thesis research, we first unveil the fundamental theory and output characteristics of triboelectric nanogenerators. Then, we apply the developed theory to the TENG-based self-powered system design. We have developed the first genuine self-powered system to meet mW requirement of personal electronics. The system includes a multilayered TENG, a power management circuit with 60% total efficiency, and a low leakage energy storage device. Our power management circuit provides the total efficiency that is about two magnitudes higher than the traditional direct charging. And the total system performance is 330 times higher than the state-of-art designs. Driven by palm tapping, this power unit can provide a continuous DC electricity of 1.044 mW on average power in a regulated and managed manner that can be universally applied as a standard power source for continuously driving numerous conventional electronics, such as a thermometer, a heart rate monitor (electrocardiograph/ECG system), a pedometer, a wearable electronic watch, a scientific calculator, and a wireless radio-frequency communication system. Our study demonstrates the first power unit that utilizes widely accessible biomechanical energy source to sustainably drive a broad range of commercial mobile and wearable electronic devices. This self-charging unit is a paradigm shift towards infinite-lifetime energy sources that can never be achieved solely by batteries.

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Xu, Chen. "Hybrid cell for harvesting multiple-type energies." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44782.

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An abundance of energy in our environment exists in the form of light, thermal, mechanical (e.g., vibration, sonic waves, wind, and hydraulic), magnetic, chemical, and biological. Harvesting these forms of energy is of critical importance for solving long-term energy needs and the sustainable development of the planet. However, conversion cells for harvesting solar energy and mechanical energy are usually independent entities that are designed and built following distinct physical principles. The effective and complementary use of such energy resources whenever and wherever one or all of them are available demands the development of innovative approaches for the conjunctional harvesting of multiple types of energy using an integrated structure/material. By combining solar and mechanical energy-harvesting modules into a single package for higher energy conversion efficiency and a more effective energy recovery process, the research has designed and demonstrated a hybrid cell for harvesting solar and mechanical energy. The results of the research show that we can fully utilize the energy available from our living environment by developing a technology that harvests multiple forms of both solar and mechanical energy 24 hours a day. As the proposed research represents a breakthrough in the innovation of energy harvesting, it should pave the way toward building a new field called "multi-type hybrid" energy harvesting.

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Hodzic, Naida. "Study of triboelectric kinetic energy harvester with an asymmetric double variable capacitor implemented in a bennet doubler." Electronic Thesis or Diss., Université Gustave Eiffel, 2022. https://these.univ-paris-est.fr/intranet/2022/UEFL-2022/TH2022UEFL2072.pdf.

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La récupération de l'énergie est le processus qui consiste à convertir l'énergie inutilisée présente dans notre environnement en énergie électrique utilisable pour alimenter un système électronique. Les récupérateurs d'énergie cinétique à transduction électrostatique (eKEH) utilisent l'énergie cinétique présente dans l’environnement, qui provient d'un objet en mouvement ou de vibrations, afin de la convertir en énergie électrique. Le principe employé est basé sur un condensateur variable polarisé. En ajoutant une couche triboélectrique entre ses armatures et en créant un contact entre elles, un eKEH devient ce qui l’on appelle communément un nanogénérateur triboélectrique (TENG). Ce type de transducteur accumule des charges par contact dans la couche triboélectrique qui devient ainsi un électret dont le champs électrique semi-permanent généré permet une variation de la distribution des charges électriques dans les électrodes par induction électrostatique.La modification de l'architecture d'un TENG par l'ajout d'une troisième électrode permet de transformer un transducteur à capacité simple en un TENG à capacité double. Le fait de doubler l'élément de conversion dans un transducteur doit permettre d’augmenter la quantité d'énergie convertie. Le circuit électronique choisi pour redresser le signal obtenu en sortie du générateur est le doubleur de Bennet. L’absence de tension de saturation en sortie de ce circuit est une caractéristique particulière de cette pompe de charge dite instable. Elle se traduit par une augmentation exponentielle de la tension de sortie et des charges accumulées dans le condensateur de stockage qui augmentent (en théorie) de manière infinie. Cela signifie que la surface du cycle charge-tension aux bornes du TENG, et donc l’énergie convertie du domaine mécanique, augmente à chaque itération du cycle mécanique du transducteur.Cette thèse comprend l'analyse, la simulation et la démonstration expérimentale d’un doubleur de Bennet comportant deux capacités variables asymétriques incluant chacune une couche triboélectrique. Il est montré que les performances du système « double TENG » - « double Bennet » sont supérieures au doubleur de Bennet classique. L'étude analytique s'aligne sur les simulations. Le système a été testé expérimentalement. Il en est conclu que les résultats expérimentaux sont pertinents lorsqu'ils sont comparés aux performances du système classique d’un « TENG mono-capacitif » - « Bennet simple». Par rapport au doubleur de Bennet classique, le double Bennet atteint les mêmes niveaux de tension en moins de temps. Cela est dû à l'avantage du double condensateur TENG qui augmente le nombre de charges accumulées par cycle mécanique. L'analyse a montré que les deux condensateurs TENG sont co-dépendants et qu’ils s’influencent mutuellement lorsqu’ils sont mis en fonction.Le signal de sortie du double Bennet est caractérisé par des tensions élevées allant de plusieurs centaines à plusieurs milliers de volts. Pour abaisser la tension redressée en sortie à un niveau compatible avec une application commerciale, un convertisseur DC-DC de type Buck est implémenté. Celui-ci nécessite un interrupteur. Cette thèse propose et étudie l'utilisation d'un interrupteur haute-tension MEMS dit à micro-plasma dont la tension d’actionnement est définie par la loi de Paschen. Cette thèse se conclue par une étude théorique et expérimentale de cette loi à l'échelle micrométrique dans le but de proposer des tensions d’actionnement optimales pour une meilleure gestion de l'énergie captée
Energy harvesting is the process that involves converting otherwise unused energy present in our environment into usable electrical energy that can be used to power an electronic system. Electrostatic kinetic energy harvesters (eKEHs) utilize vastly present kinetic energy that originates either from an object in motion or vibrations and converts it into electrical energy. The employed principle is based on a polarized variable electrostatic capacitor. With an addition of a triboelectric layer between its plates and utilizing the triboelectrification effect, an eKEH is transformed into a triboelectric nanogenerator (TENG). This type of transducer accumulates charges by contact in the triboelectric layer which thus becomes an electret whose generated semi-permanent electric field allows a variation of the distribution of the electric charges in the electrodes by electrostatic induction.Altering the architecture of a TENG by adding the third electrode, a single-capacitive transducer is converted into a double-capacitive TENG. Doubling the conversion element in a transducer is expected to increase the amount of converted energy. Chosen electronics circuit to condition obtained signal from the generator is Bennet’s charge doubler. An increase without saturation point at the output of this circuit is the unique characteristic of this unstable charge pump. It reflects through an exponential increase of output voltage and a number of charges accumulated in the storage capacitor which increase (in theory) in an infinite way. This means that the surface of the charge-voltage cycle at the terminals of the TENG, and thus the converted energy of the mechanical domain, increases at each iteration of the mechanical cycle of the transducer.The scope of this thesis encompasses the simulation, analytical and experimental research of Bennet’s charge doubler with two asymmetric variable capacitors each containing a triboelectric layer. It is postulated that the performance of the "double TENG" - "double Bennet" system is superior to the classic Bennet’s double. The results of analytical and simulation analysis have shown that the expected behavior of this circuit aligns with hypothesized performance results. The system has been tested experimentally. It is concluded that the results of the constructed system are relevant when compared with the reported performance of the classic "single-capacitive TENG" - "Bennet’s doubler" system.When compared with classic Bennet’s doubler, double Bennet reaches the same voltage levels in less time. That is due to the advantage of double capacitive TENG which increases the number of accumulated charges per mechanical cycle. In analytical analysis, it was found that the two TENG capacitors are codependent and that in operation they affect one another.The output signal of double Bennet is characterized by high voltages ranging from a few hundreds of volts to a few kilovolts (kV). To reduce the rectified output voltage to a level compatible with a commercial application, a Buck DC-DC converter is implemented. This requires a switch. This thesis proposes and studies the use of a high-voltage MEMS micro-plasma switch whose actuation voltages is defined by Paschen’s law. Within the scope of this thesis, the theoretical and experimental studies of this law at the micrometer scale propose optimal actuation voltages for better management of the converted energy

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Dahiya, Abhishek Singh. "Nanostructures en ZnO pour l'électronique et la récupération d'énergie." Thesis, Tours, 2016. http://www.theses.fr/2016TOUR4007/document.

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Les nanomatériaux et nanotechnologies sont devenus un élément incontournable dans l'électronique de faible puissance, la production énergétique / gestion et les réseaux sans fil, offrant la possibilité de construire une vision pour les capteurs autonomes. Cette thèse s’intéresse au concept de systèmes basse température utilisant des structures de matériaux hybrides organique/inorganique pour la réalisation de dispositifs électroniques faible coût, dont les transistors à effet de champ (FET) et les nanogénérateurs piézoélectriques (nommés PENGs) et ce, sur divers substrats en particulier plastiques. Pour atteindre ces objectifs, ce travail décrit d'abord la croissance contrôlée de nanostructures monocristallines de ZnO en utilisant des approches vapeur-liquide-solide (VLS) et hydrothermales à haute et basse température respectivement. Pour les dispositifs FET, les nanostructures ZnO obtenues par VLS sont utilisées en raison de leur haute qualité structurale et optique. Les sections suivantes présentent des différentes études menées pour optimiser les prototypes FET, comprenant (i) les contacts métal-semiconducteur, (ii) la qualité de l'interface semi-conducteur/isolant et (iii) l'épaisseur de diélectrique organique. La dernière section examine la possibilité de fabriquer des systèmes hybrides organiques/inorganiques pour PENGs utilisant l'approche hydrothermale. Certaines des questions clés, ce qui limitent les performances PENG sont abordés : (i) l'effet de porteurs libres et (ii) l'encapsulation polymère. Ce travail démontre le fort potentiel des ZnO nanostructures pour l'avenir de l'électronique
Nanomaterials and nanotechnology has become a crucial feature in low-power electronics, energy generation/management and wireless networks, providing the opportunity to build a vision for autonomous sensors. The present thesis delivers the concept of low-temperature processable organic / inorganic hybrid systems for the realization of inexpensive electronic devices including field-effect transistors (FETs) and piezoelectric nanogenerators (PENGs) on various substrates including plastics. To achieve these objectives, this work first describes the controlled growth of single-crystalline ZnO nanostructures using high-temperature vapor-liquid-solid (VLS) and low-temperature hydrothermal approaches. For the FET devices, VLS grown ZnO nanostructures are used, owing to their high structural and optical quality. Later sections present different studies conducted to optimize the FET prototypes, includes: (i) metal-semiconductor contacts, (ii) semiconductor/insulator interface quality and (iii) organic dielectric thickness. The last section investigates the possibility to fabricate organic / inorganic hybrid systems for PENGs using hydrothermal approach. Some of the key issues, restricting the PENG performances are addressed: (i) screening effect from free charge carriers and (ii) polymer encapsulation. This work demonstrates the high potential of ZnO nanostructure for the future of electronics

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Mellea, Antonio, and Antonio Mellea. "Energy Harvesting per l’autonomia di dispositivi cardiaci impiantabili." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.

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L’obiettivo di questo elaborato è di approfondire la tematica dell’energy harvesting per la microscala e studiarne le tecnologie, al fine di vagliarne l’opportunità di integrazione in dispositivi cardiaci impiantabili. Queste tecnologie, permettono la raccolta di energia prodotta dal corpo umano, ed in particolare dal sistema cardiocircolatorio. Dato che le attuali sorgenti energetiche che alimentano i dispositivi cardiaci impiantabili, come le batterie, rivelano alcune criticità, il dispositivo dotato di energy harvester gioverebbe sia dal punto di vista economico che socio-sanitario. In questo elaborato sono due gli approcci presi in considerazione, il primo riguarda il concetto di Energy Harvesting in senso stretto, per sistemi in grado di attingere energia da fonti sostenibili nell’ambiente di impianto e trasformarla in energia elettrica per l’alimentazione del dispositivo. Il secondo approccio rappresenta un’estensione del concetto di harvesting, in quanto ci si riferisce al trasferimento transcutaneo di energia. Ogni tipologia presentata i propri vantaggi e le proprie criticità ma, data la fase embrionale in cui questi dispositivi ancora riversano, e soprattutto, le criticità legate all’aleatorietà nei comportamenti a lungo termine aggiunto al basso output in potenza, pensare di rendere i dispositivi autoalimentati appare, ancora oggi, un’idea avveniristica. Dotare, invece, i dispositivi impiantabili di un energy harvester in grado di percepire vibrazioni ultrasoniche al fine di ricaricare la batteria, come quella di un pacemaker, sembra una soluzione concreta e reale, praticabile anche in termini di potenza. Questa analisi ha come obbiettivo finale quello confrontare le tecnologie più promettenti nel settore dell’energy harvesting per applicazioni cardiache con la speranza che questo settore possa un domani giocare chiave orientando la ricerca in campo medico/diagnostico verso soluzioni sostenibili ed integrate, a supporto del paziente.

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Černohorský, Petr. "Elektrospřádaná vlákna na bázi PVDF a nylonu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442506.

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Polymer nanofibers used for the construction of triboelectric nanogenerator (TENG) and piezoelectric nanogenerator (PENG) are new and promising technologies for energy recovery. Thanks to the generation of electrical energy based on mechanical movement (deformation), these fibers can find application in the field of self-powered electronic devices. In this work, three nanofibrous structures of materials were prepared by electrostatic spinning: pure polyvinylidene fluoride (PVDF), pure polyamide-6 (PA6) and their mixed combination PVDF / PA6. Non-destructive analyzes such as Raman spectroscopy, FTIR, XPS and electron microscopy were used to study the properties of nanofibers. Analyzes confirmed the positive effect of electrostatic spinning of polymers on the support of the formation of highly polar crystalline -phase in PVDF and , -phase in PA6. The structure arrangement of the nanofibrous material and their defects were observed by scanning electron microscopy (SEM). Furthermore, the contact angle of the wettability of the liquid on the surface was measured for the materials, and the permittivity was measured to monitor the dielectric properties. The described results make the mixed material PVDF / PA6 very promising for further research in the field of nanogenerators and functional textiles.

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Tao, Ran. "Piezoelectric generators based on semiconducting nanowires : simulation and experiments." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT094/document.

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L’alimentation en énergie des réseaux de capteurs miniaturisés pose une question fondamentale, dans la mesure où leur autonomie est un critère de qualité de plus en plus important pour l’utilisateur. C’est même une question cruciale lorsque ces réseaux visent à assurer une surveillance d’infrastructure (avionique, machines, bâtiments…) ou une surveillance médicale ou environnementale. Les matériaux piézoélectriques permettent d’exploiter l’énergie mécanique inutilisée présente en abondance dans l’environnement (vibrations, déformations liées à des mouvements ou à des flux d’air…). Ils peuvent ainsi contribuer à rendre ces capteurs autonomes en énergie. Sous la forme de nanofils (NF), les matériaux piézoélectriques offrent une sensibilité qui permet d’exploiter des sollicitations mécaniques très faibles. Ils sont également intégrables, éventuellement sur substrat souple.Dans cette thèse nous nous intéressons au potentiel des nanofils de matériaux semi-conducteurs piézoélectriques, tels que ZnO ou les composés III-V, pour la conversion d’énergie mécanique en énergie électrique. Depuis peu, ceux-ci ont fait l’objet d’études relativement nombreuses, avec la réalisation de nanogénérateurs (NG) prometteurs. De nombreuses questions subsistent toutefois avec, par exemple, des contradictions notables entre prédictions théoriques et observations expérimentales.Notre objectif est d’approfondir la compréhension des mécanismes physiques qui définissent la réponse piézoélectrique des NF semi-conducteurs et des NG associés. Le travail expérimental s’appuie sur la fabrication de générateurs de type VING (Vertical Integrated Nano Generators) et sur leur caractérisation. Pour cela, un système de caractérisation électromécanique a été construit pour évaluer les performances des NG réalisés et les effets thermiques sous une force compressive contrôlée. Le module d’Young et les coefficients piézoélectriques effectifs de NF de GaN; GaAs et ZnO et de NF à structure cœur/coquille à base de ZnO ont été évalués également dans un microscope à force atomique (AFM). Les nanofils de ZnO sont obtenus par croissance chimique en milieu liquide sur des substrats rigides (Si) ou flexibles (inox) puis sont intégrés pour former un générateur. La conception du dispositif VING s’est appuyée sur des simulations négligeant l’influence des porteurs libres, comme dans la plupart des études publiées. Nous avons ensuite approfondi le travail théorique en simulant le couplage complet entre les effets mécaniques, piézoélectriques et semi-conducteurs, et en tenant compte cette fois des porteurs libres. La prise en compte du piégeage du niveau de Fermi en surface nous permet de réconcilier observations théoriques et expérimentales. Nous proposons notamment une explication au fait que des effets de taille apparaissent expérimentalement pour des diamètres au moins 10 fois plus grands que les valeurs prévues par simulation ab-initio ou au fait que la réponse du VING est dissymétrique selon que le substrat sur lequel il est intégré est en flexion convexe ou concave
Energy autonomy in small sensors networks is one of the key quality parameter for end-users. It’s even critical when addressing applications in structures health monitoring (avionics, machines, building…), or in medical or environmental monitoring applications. Piezoelectric materials make it possible to exploit the otherwise wasted mechanical energy which is abundant in our environment (e. g. from vibrations, deformations related to movements or air fluxes). Thus, they can contribute to the energy autonomy of those small sensors. In the form of nanowires (NWs), piezoelectric materials offer a high sensibility allowing very small mechanical deformations to be exploited. They are also easy to integrate, even on flexible substrates.In this PhD thesis, we studied the potential of semiconducting piezoelectric NWs, of ZnO or III-V compounds, for the conversion from mechanical to electrical energy. An increasing number of publications have recently bloomed about these nanostructures and promising nanogenerators (NGs) have been reported. However, many questions are still open with, for instance, contradictions that remain between theoretical predictions and experimental observations.Our objective is to better understand the physical mechanisms which rule the piezoelectric response of semiconducting NWs and of the associated NGs. The experimental work was based on the fabrication of VING (Vertical Integrated Nano Generators) devices and their characterization. An electromechanical characterization set-up was built to evaluate the performance and thermal effects of the fabricated NGs under controlled compressive forces. Atomic Force Microscopy (AFM) was also used to evaluate the Young modulus and the effective piezoelectric coefficients of GaN, GaAs and ZnO NWs, as well as of ZnO-based core/shell NWs. Among them, ZnO NWs were grown using chemical bath deposition over rigid (Si) or flexible (stainless steel) substrates and further integrated to build VING piezoelectric generators. The VING design was based on simulations which neglected the effect of free carriers, as done in most publications to date. This theoretical work was further improved by considering the complete coupling between mechanical, piezoelectric and semiconducting effects, including free carriers. By taking into account the surface Fermi level pinning, we were able to reconcile theoretical and experimental observations. In particular, we propose an explanation to the fact that size effects are experimentally observed for NWs with diameters 10 times higher than expected from ab-initio simulations, or the fact that VING response is non-symmetrical according to whether the substrate on which it is integrated is actuated with a convex or concave bending

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Guo, Chi-Heng, and 郭啟珩. "barium titanate nanofibers/PVDF nanogenerator." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/z3x9zd.

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碩士
國立中央大學
化學工程與材料工程學系
107
This research was focused on the affects of electrical output by adding various contents of barium titanate (BT) nanofibers of BT/PVDF or BT/P(VDF-TrFE) mats which were synthesized by far-field electrospinning. First, BT/PVP sol for electrospinning was synthesized. After electrospinning, the BT/PVP nanofiers was annealed at 800oC for two hours to remove PVP and produced BT nanofibers with tetragonal phase which is characteristic with piezoelectricity. The BT nanofibers were oxidized by hydrogen peroxide then surface modified with dopamine. Also, we have tried to suspend BT nanofibers by only viscosity in PVDF sol. Consequently, Modified BT fibers can be added up to 63 wt% and suspend at least for 2 hours without precipitation. The pure BT nanofibers can also be added up to 57 wt%. The composite piezoelectric mats were synthesized by electrospinning. Subsequently, the mat was attached two electrodes and electric wires then sealed by PDMS encapsulant which was cured by heating and become a flexible sheet. The PDMS encapsulant was applied a up and down strain by a self-made device and generate electric potential. According to our measurements, no matter the BT nanofibers were added or not, the electrical output of PVDF and P(VDF-TrFE) were almost the same. On the other hand, when the BT nanofibers were added up to 63 wt%, the electric outputs were enhanced by 6 times. On the basis of the 11 methods which can confirm the electric output of a nanogenerator is generated by piezoelectric instead of triboelectric were presented by Prof. Z. L. Wang. Therefore, we have selected and carried out 4 of them, and it can be proved that the electric output is generated by piezoelectric. It is revealed that we utilized the far-field electrospinning method can produce random aligned mats which still can generate alternative current by piezoelectric.

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Yu, Yi-Kuei, and 游一魁. "Characteristics of ZnO Nanowire for Flexible Nanogenerator." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/71744989005388504584.

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林家彬. "Study on Nanogenerator Made from Nanostructure BiFeO3." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/24126770989727427102.

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Lee, Ching-Chin, and 李俊慶. "Piezoelectric nanogenerator system with ZnO epitaxial nanostructures." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/ye67sa.

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碩士
國立虎尾科技大學
光電與材料科技研究所
96
ZnO has some of the greatest potential among semiconductor materials for application in ultraviolet regions and nanotechnology. It has large exciton binding energy of about 60 meV, which is much greater than the thermal energy at room temperature, makes it a promising candidate for applications in blue-UV light emission and room-temperature UV lasing. ZnO is known to have wurtzite strucuture with lattice constant a = 3.249 Å, c = 5.207 Å. Furthermore, its highly piezoelectric constant makes it a highly valuable material for fabricating mechanical devices. For instance, ZnO thin film structures can be utilized as piezoelectrical device and ultraviolet light emitting diode. Several physical or chemical methods have been developed in succession for the preparation of ZnO nanorod/nanowire array, including vapor-liquid-solid process untilizing gold or tin as catalyst, metalorganic vapor-phase epitaxial growth, seed-layer assisted solution route, electrochemical deposition based on anodic alumina membranes, and so on. Compared with physical vapor methods, the solution based approaches exhibited obvious advantages in cost, facilities, complexity, energy consumption, and large scale up production. Self-powered nanosystems are of great importance for real-time and implantable biosensing, environmental monitoring, and electromechanical systems. We have developed a direct-current nanogenerator that is driven by ultrasonic wave. The basic principle is to use piezoelectric and semiconducting coupled nanorods(NRs), such as ZnO, to convert mechanical energy into electricity. The ZnO nanostructures were symthesized on different substrates using chemical depostion methods. In this experiment, ZnO nanostructrues grown included vapor and liquid solution epitaxial methods. In vapor epitaxial, effect of growth temperatures, Zn/C powder ratios, of gas ratios on the morphology and characteristics of ZnO naonowires were carried out. In liquid epitaxial, effect of growth temperatures, growth times, and of solutions of pH on the morphology and characteristics of ZnO naonorods were discused. The photoluminescence(PL) and transmittance of the ZnO nanostructures were measured by UV-VIS spectrophotometer and fluorescence spectrophotometer. The sanning electron microscope(SEM) results showed when the temperatures increased, the diameters of the ZnO grains increased. The ZnO nanowires and nanorods had a mean diameter of ~80 nm. The XRD results found that the ZnO nanorods had monocrystalline(002) structure by low temperature that the highest intensity at 90℃ and concentration ratio 2：4, and the ZnO nanowires exhibited polycrystalline structure by high -temperature method that the highest intensity at 800℃ and oxygen ratio 12：1. ZnO is a II-VI semiconductor with a band gap of 3.2 eV at room temperature. The photoluminescence measurements showed that the high-temperature epitaxial ZnO nanostructures had good ultraviolet emission at 382 nm and blue emission at 500 nm. The high-temperature epitaxial method PL characteristic quality more than low-temperature epitaxial method. Raman scattering spectrum was used to measure substance structure of the ZnO nanostructure. The raman scattering spectrum appeared two peaks at 438 cm-1 and 582 cm-1. The transmittance and absorption spectrums measurements showed that the ZnO nanorods had high transmittance 90% at 900 nm and good ultraviolet absorption at 350 nm. Transmission electron microscope(TEM) was used to measure crystal image and inner structure. Finally, making on top of electrode to fabricate nanogenerator(NG) with ZnO nanorods and measured micro-current driven by ultrasonic waves with a frequency of 43 kHz. When the ultrasonic wave was on for an extended period of time, the generated current was ~25 nA for a NG with 25 mm2 in size, corresponding to an output current density of 0.1μA/cm2 .

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25

Pan, Wei-Pang, and 潘維邦. "Blue Energy Harvesting by Using Triboelectric Nanogenerator." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/hce49w.

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碩士
國立臺灣大學
應用力學研究所
107
In this study, we develop a triboelectric nanogenerator combined with a crank-and-rod structure and applies it to blue energy harvesting. In the experiment, aluminum and polytetrafluoroethylene were used as the positive and negative electrode respectively attached to the slider and the slide rail, and combined with the link mechanism to convert the blade rotation caused by the water flow into a periodic motion, so that the slider connected with the connecting rod produce relative motion with the slide rails to generate electrical energy. In this study, we use the in-plane sliding mode triboelectric nanogenerator, which is easier to design than the vertical contact-separation mode triboelectric nanogenerator. The electrode on the slide rail uses a grid structure, which can make multiple frictions to increase the current output in a single motion to improve the high voltage and low current characteristics of the triboelectric nanogenerator. The addition of a spring on the slider ensures close contact of the material surface, which can improve the wear of the material caused by prolonged operation and reduce the output. Besides, compared with the traditional triboelectric nanogenerator that used to blue energy harvesting, there is a problem of sealing. In this study, the design of the linkage mechanism enables the triboelectric nanogenerator to generate electricity on the water surface to prevent water from affecting the contact of the surface of the material and causing output instability. In this study, the effects of different electrode areas, grid electrode pairs, number of friction surfaces, friction frequency, and spring constant on the output were tested. And measure the change in the output of the triboelectric nanogenerator under different loads in the optimized case. The experimental results show that the triboelectric nanogenerator can generate an open circuit voltage of 40 V, a short-circuit current of 5.3 μA, and a power density of 7.3 mW/m2. This output can effectively drive small electronic sold in the market. It is expected that this triboelectric nanogenerator can be a new form of power generation through array or size amplification.

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26

"Applying Vertically Aligned Carbon Nanotubes in Energy Harvesting and Energy Storage." Tulane University, 2017.

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27

Sheng-ShongWong and 翁聖翔. "Piezo-phototronic Effects of InGaN Nanorod Piezoelectric Nanogenerator." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/txnp22.

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28

Yang, Shin-shing, and 楊信興. "Flexible piezoelectric nanogenerator system with ZnO epitaxial nanostructures." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/uaxdfw.

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碩士
國立虎尾科技大學
光電與材料科技研究所
97
The ZnO nanostructures were synthesized on flexible soft substrate using chemical deposition methods. We applied the epitaxial growth to produce ZnO nanorods and assembled the nanogenerator with the nanorods. ZnO nanostructures were grown using liquid solution epitaxial method. In liquid epitaxial, effects of growth temperatures, growth times, and growth concentrations on the morphology and characteristics of ZnO nanorods were discussed. The results showed when the temperatures increased, the diameters of the nanowires increased. The XRD results found that the ZnO nanowires had monocrystalline (0002) structure. The ZnO nanostructures had good peak values in ultraviolet emission and blue emission. Finally, making on top of electrode to fabricate nanogenerator with ZnO nanorods and measured micro-current driven by ultrasonic waves, and measuring its voltage and current characteristics. To explore how different deflections of the electromechanical characteristics change with the state of bending in the substrate.

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29

Yi-JuChen and 陳依孺. "Development of MgxZn1-xO thin films for piezoelectric nanogenerator." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/67sgdd.

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30

Yu-LunSu and 蘇宇倫. "Piezotronics and Nanogenerator Enhancement Through Porous ZnO Nanowire Arrays." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/g3kx9g.

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31

Su, Che-Hsiang, and 蘇蜇翔. "Study of Preparation ZnO Nanogenerator Electrode by Low Cost Method." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/yjzk4w.

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碩士
國立虎尾科技大學
電子工程系碩士班
105
Zinc oxide is a II-VI semiconductor material with direct band-gap of 3.37eV corresponding to the wavelength in the ultraviolet region and it also has large exction binding energy (~60 meV). In addition, ZnO has the characteristic of low resistivity and high transparency, therefore, it is considered as a promising material for the application of the optoelectronics. In this study, ZnO film is deposited by sputter on ITO glass substrate, and ZnO nanorods nanostructure are grown by hydrothermal. One dimensional type of nanostructure was analysed physical properties of ZnO nanorods optical properties by XRD, FE-SEM, EDS. ZnO nanorods are grown on ITO glass, then fabricate naogeneratator by making top electrode. Nanogenerator are driven by ultrasonic waves. ZnO nanorods are grown 6 hours and measured its voltage and current. The average current and average voltage are 3.46×10-6A and 5.63×10-2V respectively. The use of an etching electrode to increase the contact area also results in good voltage-current characteristics.

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32

Ye, Jia-Cheng, and 葉家成. "Massively aligned piezoelectric nanofibers as nanogenerator and self-powered deformation sensor." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/20098769227918235715.

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碩士
國立中央大學
能源工程研究所
101
This thesis mainly research fabrication of nanogenerator, piezoelectric technology and application in electrospinning. The focus of the study is (1) Massively parallel aligned nanofibers-based nanogenerator deposited via near-field electrospinning, (2) Superposition of nanogenerator and measurement, (3) A flexible, self-powered deformation sensor based on nanogenerator. we demonstrate a direct-write, in-situ poled polyvinylidene fluoride (PVDF) nanofiber arrays that could functions as a self-powered active deformation sensor. The fabricated hybrid structure of sensor/nanogenerator (NG) is realized via direct deposition of near-field electrospun nanofibers on Cu-foil electrode of thickness ~200 μm and fully encapsulated on a flexible substrate. Capable of integrating into fabric such as a waving flag due to high flexibility and excellent conformability, the nanofiber-based device can serve as an active deformation sensor under ambient wind-speed and the feasibility of efficiently convert the flutter motion into electricity are also demonstrated. This low-cost, simple structure, high sensitivity and good environment-friendly nanofibers is a very promising material/technology as practical energy harvesting devices and self-powered sensors and capable of scavenging very small wind power or mechanical induced vibration.

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33

Hsu, Nai-Feng, and 許乃鋒. "Techniques for Synthesis of Metal Oxide Nanowires and Applications to the Nanogenerator." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/26229140390415578888.

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博士
中原大學
機械工程研究所
99
Oxide assisted vapor-solid (VS) process has been used for rapid crystal growth of α-Fe2O3 and Fe3O4 nanowires (NWs) on Fe:Ni (1:1) alloy substrate, and of ZnO NWs array on Zn substrate. Oxide layers have been created initially on the Fe:Ni (1:1) substrate or Zn substrate by heating it inside the quartz tube of a single tube furnace in air. The substrate is Fe:Ni (1:1) alloy or Zn piece prior immersed in solution of oxalic acid. Raise the temperature of the quartz tube to prior set temperature in vacuum and flow argon (Ar) for 20 mins. Introduction of Ar carrier gas in the step can help the axis grow NWs on the oxide layer. In the process, the grown NWs diameters can maintain below 200 nm with lengths reaching to 10 μm and the entire synthesis of NWs can be completed within 1.5 hrs. Capillarity model and resident time theorem have been combined to analyze the nanowire growth process. Vibrating sample magnetometry (VSM) study show that α-Fe2O3 and Fe3O4 NWs are high magnetic materials. Additionally, the grown ZnO NWs are proved there is good crystal quality with few oxygen vacancies on the surface by the Raman scattering and PL spectrum. In this work, an experimental method applied to discuss influence of oxalic acid for the crystalline phase of iron oxide NWs. Experimental results indicate that grown NWs are α-Fe2O3 crystalline as Fe:Ni (1:1) alloy is immersed in water. However, as Fe:Ni (1:1) alloy is prior immersed in a solution of oxalic acid with low concentration, few NWs grew to become Fe3O4. The saturated state of Fe3O4 NWs is achieved as the oxalic acid concentration reaches 0.75 mol/L, and grown NWs mainly are Fe3O4 crystalline phase in the concentration. Further, some of the Fe3O4 NWs aggregate to appear particles in extremely gas flux as Fe:Ni (1:1) alloy is prior immersed in a solution of oxalic acid, and these particles combine to form bulk as raising oxalic acid concentration to 0.75 mol/L. Furthermore, there are not obviously varieties for grown products as varied dripping time at various oxalic acid concentrations. Moreover, mechanical properties of Fe3O4 nanowires are investigated by a nano-tensile testing technique using a custom-made nanomanipulator inside the SEM. The modulus of elasticity, yield stress and fracture stress of Fe3O4 NWs are estimated to be 23.8 ± 3.8 GPa, 428 ± 55 MPa and 1.10 ± 0.29 GPa, respectively. Strain range at breaking of NWs is obtained 5% to 11%. The results indicate that the Fe3O4 NWs have highly malleable and stretching properties. Eventually, a system of nanogenerator can be developed by integral magnetic NWs and ZnO NWs of growth on substrates. In this system, magnetic substrate with growth magnetic NWs bend ZnO NWs by repeatedly vibration to stimulate a PZ effect and magnetic-induce-current under an extra magnetic field. The results discovered that there is a high output current approximately 52 μA/1.5cm×3cm (the area 1.5cm×3cm is including package area 3.5cm2 and piezoelectric area 1cm2) under Br (magnetic flux density) is 400 mT. This system has possessed ability to alight LED, which may be developed to become green energy in the future.

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34

Lin, Hung-I., and 林宏易. "Fabrication and Characterization of a Flexible ZnO Nanogenerator for Harvesting Energy from Respiration." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/97tm3w.

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碩士
國立中興大學
材料科學與工程學系所
101
Replacing batteries by harvesting energy from human respiration is a promising technology for self-powered systems using the concept of nanogenerators (NGs). ZnO is a semiconductor material with unique piezoelectric property has been discussed recently. A novel ZnO nanogenerator with a flexible and highly lightweight substrate has the potential of harvesting energy from human respiration. We introduce a lifting-off method of ZnO nanowires from Si substrate and embedded in flexible films-epoxy resin has been proposed. Flexible films served as the secondary and flexible substrate after ZnO nanowires transferring from the Si substrate. The piezoelectric potential of a ZnO nanogenerator can produce AC power output during respiration. For normal human respiration at an air flow rate of 2.0 ms-1 and tidal volume 500 mL, the ZnO nanogenerator generates current-density and voltages of 3.65 nA and 27.32 mV, respectively. The electrical performance reached the highest value of 11.21 nA and 67.25 mV at an air flow rate of 5.0 ms-1 and tidal volume 1000 mL. To obtain the high-output piezoelectric performance, fold-up fabrication method is introduced and polydimethylsiloxane (PDMS) is used as the flexible film. The thickness of the 2-fold ZnO NG was approximately 25 μm, and the 16-fold ZnO NG had a comparatively low size of approximately 200 μm. The 16-fold ZnO NG generates approximately 0.6 V and 0.5 μA at the air flow rate of 2.0 ms-1, while generating approximately 1.3 V and 0.8 μA at the air flow rate of 5.0 ms-1. The lift-off and fold-up methods are both candidates for creating devices that can harvest energy from human respiration.

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35

Liang-CiaoYang and 楊量喬. "Piezoelectric Nanogenerator of MgxZn1-xO and ZnO Thin Films by Oblique Angle Sputtering." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/e8ehpt.

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36

Hsiao, Yung-Chi, and 蕭勇麒. "Waterproof Textile-based Triboelectric Nanogenerator for Harvesting Rain, Wind, and Human-motion Energy." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/nq9tz9.

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碩士
國立中興大學
材料科學與工程學系所
106
A newly-designed waterproof textile-based triboelectric nanogenerator (TENG) have been demonstrated. The device was constructed by silicone rubber, woven conducting textiles, nylon mesh spacer, and ethylene vinyl acetate textile. The physical mechanism of TENG is related to Maxwell’s displacement current, in short, it’s based on a coupling effect of contact electrification and electrostatic induction. This result is endowed phenom of triboelectrification, which was constructed as a negative influence in past, the positive and useful value in more applications. For example, this waterproof textile-based TENG is able to harvest universal low- and random-frequency mechanical energy and power up the personal electronics such as the light emitting diodes or charging the capacitors. The maximum output by raindrop can reach up to 1900 V/m2, 160 μA/m2, and 20 μW/m2; for wind, the output can approach to 2000 V/m2, 150 μA/m2, and 70 μW/m2; by human motion, the output can reach up to 300 V, 40 μA, and 1 mW. Furthermore, by integrating with microcomputer system for data acquisition and processing, the waterproof textile-based TENG was demonstrated as the self-powered sensor for actively human-interactive interfaces and combining with the wireless transmitter, which was able to remote manipulation computer for playing music. It is believed the waterproof textile-based TENG can be beneficial for the development of wearable electronics and smart clothing.

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37

Liang, Jia-Ru, and 梁家儒. "Synthesis of Titanium Dioxide Structural Thin Films and Their Application in Triboelectric Nanogenerator." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/sqp9wf.

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碩士
國立聯合大學
能源工程學系碩士班
107
Triboelectric nanogenerator TENG is an important objective in the research of micro-self-powered systems. However studies of positive electrode materials are rarely reported. Here, we focused on the development of positive electrode materials by introducing two TiO2 nanostructural thin films via anodization method and study the output performance of TENG. The first part of the study is anodized TiO2 thin film. We control the external bias voltage of anodizing from 10 V to 100 V to prepare TiO2 films with different thicknesses. The triboelectric generation performance of the TiO2 films is decrease from 10 V-film 30 V-film, increase from 40 V-film to 60 V-film, and decrease from 60 V-film to 100 V-film due to an increase in the thickness of the dielectric layers. The maximum value of the triboelectric generation is 24 V for the 60 V-film; and the minimum is 2.4 V for the 30 V-film. In another part, TiO2 nanotube arrays (TNT) were fabricated as positive electrode for TENG with anodization method in electrolvte containing ethylene glycol,HF and H2O at bias of 30 V and temperature of 16 C. In order to study the morphology effect on the TENG performance, TiO2 film was also prepared with the same thickness of TNT. The triboelectric generation voltage is 17.5 V, which is 7 times that of the TiO2 films. The results reveal that the TENG performance can be further enhanced by introducing a one-dimensional nanostructural dielectric layer due to their larger surface area and one dimensional channel. The TENG output can be effectively improved by controlling the films thickness and nanotopography of TiO2 dielectric layers via anodization technique.These approaches provide great potential in TENG and their applications.

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38

Kung, Ting-Ju, and 龔亭如. "Study of the Flexible Porous Dielectric Layer and Surface Properties for a Triboelectric Nanogenerator." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/34ds7s.

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碩士
國立臺灣大學
應用力學研究所
107
The effects of triboelectrification are usually regarded as the negative physical phenomenon in fabrication processes or experiments. In order to avoid the damage caused by the accumulation of triboelectric charge, it is necessary to increase energy costs because of the additive process of removing static electricity. However, a new type of energy technology called triboelectric nanogenerator was demonstrated by Prof. Zhong Lin Wang’s group in 2012, which is available to convert mechanical energy into electrical energy by triboelectric effect. The advantages of the triboelectric devices are not only allowing high selectivity of materials but also providing a new way to design sensors. Furthermore, electricity can also be used as a power supply in small electronic devices and has the opportunity to replace the external power supply in traditional sensors. The researches have also shown that technology provides a new perspective on the fields of small electronic products and sensors. In the first part of the thesis, we fabricated porous PDMS and systematically measured the performance of the porous dielectric material. The results showed that the porosity, working frequency, the methods of applying force and the rate of separation have a strong relationship with the formation of triboelectric charge density on the surface. Compared with pure PDMS, the porous PDMS has a maximum peak to peak output voltage of 18V, which gives 4.5-time enhancement when the operating frequency is 3 Hz and the applied pressure is 62.5 kPa. In addition, when the frequency is increased from 0.7 Hz to 3 Hz, there is a significant difference between the pure PDMS and the porous PDMS output voltage. The preparation of the porous PDMS in this study provides a low-cost, large-area manufacturing method compared to the chemical solvent dissolution method. Furthermore, we also attempt to provide optimum operating parameters of porous PDMS under the triboelectric device, which makes it useful for the applications of soft sensors in the robot industry and wearable devices. In the second part, we modified PDMS surfaces using plasma treatment. The results of the voltage of the porous PDMS was not obviously increased. However, it was found that if the surface was cleaned with 75% ethanol after the plasma treatment, the voltage signals gradually reversed which means the displacement current flows in the opposite direction between the upper and lower electrodes. The results suggest that the ions in the ethanol solution anchored on the reactive functional groups of the PDMS surface and changed the charge property. The modification of the surface can be applied to designing a surface charge pattern and electrostatic self-assembly of charged particles on the surface. Finally, we propose a new sensor based on the single electrode mode of triboelectric nanogenerator which can detect the direction due to the designable surface structure. The contact area is proportional to the voltage signal which can identify the moving direction of the finger on the structure. The design can also be extended to the applications of tactile sensors and electronic skin.

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39

Chung-YehLin and 林君曄. "GaN Nanorod Piezoelectric Nanogenerator Grown by Plasma-assisted Molecular Beam Epitaxy with Si Pyramid Substrate." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/2eaqx7.

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碩士
國立成功大學
物理學系
103
Piezoelectric Nanogenerator is a new frontier of harvesting ambient mechanical energy. Currently, the most common structure of piezoelectric nanogenerators is vertical integrated nanowire nanogenerator (VING). However, the VING was hardly utilized the piezoelectric advantage of blending nanowires. Here, using molecular beam epitaxy system (MBE), we have built a GaN nanowires nanogenerator based on silicon pyramid substrate to harvesting more mechanical energy and compare with traditional VING structure. The experimental results show that nanowire nanogenerator based on silicon pyramid substrate is substantially superior than the VING nanogenerator in terms of output piezoelectric voltage.

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40

YE, YING-TONG, and 葉盈彤. "Effect of Chlorine doping in ZnO nanorod arrays on the output performance of piezoelectric nanogenerator." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/8avzz3.

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碩士
國立虎尾科技大學
電子工程系碩士班
107
Piezoelectric nanogenerator (PENG) is an emerging green energy alternative. ZnO has the characteristic of low resistivity and high transparency, therefore, it is considered as a promising material for the application of the optoelectronics. By changing the doping of the semiconductor surface chemistry is an effective method, the study proved that zinc oxide nanorods array chlorine doping can significantly improve the output performance of PENG. Hydrothermal growth of low density chlorine-doped zinc oxide nano-pillar structure on ITO glass without seed layer and preparation of nanogenerator. Then investigate the effect of the presence or absence nanorods seed layer and the difference in chemical doping of the nanorods grown on the substrate. After sputtering Pt film on ZnO nanorod arrays, the ZnO nanorod arrays with Pt film was assembled with the unsputtered nanostructure, which was driven by ultrasonic waves. The optimal I-V characteristics of ZnO nanogenerator were 5.62⨯10-6 A and 4.17⨯10-2 V.

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41

HARSHVARDHAN and PALKIN YADAV. "SYSTEMATIC INVESTIGATION OF THE EFFECT OF SnS2 NANOFILLER CONTENT ON THE PIEZOELECTRIC PERFORMANCE OF THE PVDF-TrFE-BASED NANOGENERATOR." Thesis, 2023. http://dspace.dtu.ac.in:8080/jspui/handle/repository/19797.

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In this work, SnS2 is used as a nanofiller material to improve the response of the polymer-based piezoelectric nanogenerator because of its better inherent piezoelectric properties in comparison to other 2D materials. For this, first, nanoflakes of tin sulfide (SnS2) were synthesized via the hydrothermal method, where the high purity of SnS2 powder is confirmed by Raman spectroscopy and X-ray diffraction studies. The obtained powder of SnS2 was then mixed with PVDF-TrFE in different weight percentages (0%, 1%, 3%, 5%, and 7%) of SnS2 to synthesize polymer composite film via the drop-casting method. These films are then characterized with XRD and FTIR spectrometers, which show enhancement in the electroactive beta phase of the nanocomposite films after doping with SnS2 powder, from 58.30% to 93.07%, which is in agreement with the polarization versus electric field (P-E) measurements that show increased remnant polarization after doping. These films are then used to fabricate a piezoelectric nanogenerator by adhering aluminum tape to both sides of the films. The piezoelectric nanogenerator's (PENG) output performance is analyzed by measuring the open-circuit voltage (Voc) and short-circuits (Isc) by tapping the nanogenerator with the help of a dynamic shaker, which shows that the output performance of Trifluoroethylene (PVDF-TrFE) based PENGs gets enhanced after the introduction of SnS2 powder. The maximum piezoelectric voltage corresponding to the PENG made with 5% SnS2 was 14.4 V, which was almost 1.5 times that of the PENG made with bare PVDF-TrFE. The output piezoelectric current followed a similar trend, with the 5% SnS2 PENG producing 3.9�A of current, which was roughly 1.62 times more than the output of the bare PVDF TrFE thin film. As a result, the present study demonstrates that adding SnS2 to the PVDF matrix can significantly improve energy harvesting technologies based on PVDF's piezoelectric properties.

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42

Chen, Shao-Yu, and 陳紹瑀. "1.7 V Nanogenerator realized via direct-write, in situ poled near-field electrospun nanofibers on flexible substrate." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/58584675089801528071.

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碩士
國立中央大學
機械工程研究所
100
This thesis mainly research fabrication of nanogenerator, piezoelectric technology and application in electrospinning. The focus of the study is (1) Fabrication of nanogenerator via near-field electrospinning process, (2) Measurement and application of nanogenerator, (3) High-Throughput production of nanofibrous mats via a porous materials electrospinning Process. (1)A Facile Electrode Pattern for Voltage and Current Superposition of Near-field Electrospun Piezoelectric Nanogenerator–Fabrication and Design Harvesting energy from human motion in a routine exercise is a promising and viable approach for powering a wide range of wireless mobile electronics in our daily life. Direct-write piezoelectric polymeric nanogenerator is robust and high energy conversion efficiency such that tiny physical motions/disturbances over human operation frequencies can be stimulated and energy scavenged. Here, we demonstrate a direct-write polymeric poly (vinylidene fluoride) PVDF nanogenerator on the flexible substrate and a simple scaling-up electrode design for easy superposition of both voltage and current. (2) A Facile Electrode Pattern for Voltage and Current Superposition of Near-field Electrospun Piezoelectric Nanogenerator-Measurement and Application The nanogenerators fabricated using arrays of PVDF nanofibers in parallel and in serial configurations which are capable of producing a peak output voltage of ~1.7 V and the current reached up to 300nA. This achievement is two order of magnitude increases in both voltage and current output compared with conventional near-field setup for only one electrospun nanofiber. In addition, the alternating current output of the nanogenerator is rectified and demonstrates the technological feasibility for energy storage and recharging applications. This work shows a practical and versatile technique of using direct-write electrospun nanogenerators for powering mobile and wireless microelectronic devices. (3)High-Throughput Production of Nanofibrous Mats Via a Porous Materials Electrospinning Process A facile method is presented for the electrospinning of multiple polymer jets into nanofibers. The experiments in this study electrified 7 wt% PEO (polyethylene oxide) and 10 wt% PVDF (polyvinylidene fluoride) solutions and adopted porous materials(bars with various dimensions) to enhance the productivity of the electrospinning process. The proposed electrospinning mechanism can be used to mass produce nanofibers at a relatively lower voltage (D.C. 6~7 kV) and obtain a remarkable increase in throughput. The experimental results showed that the jets per area were on the order of 85~150jets/cm2, which is one to two orders of magnitude higher than the conventional single needle electrospinning process and can easily surpass the magnetic needleless method by a factor of 3.3 to 5.8. The proposed method of using porous materials as electrospinning devices (nozzles) should contribute to the advancement of next-generation, large-scale electrospinning systems for nanofiber fabrication.

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43

Wu, Cheng-Chang, and 吳政璋. "Exploring the Relationship between the Thickness of the Tribo-dielectric Layer and Efficiency of a Triboelectric Nanogenerator." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/wc62jx.

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碩士
國立臺灣大學
機械工程學研究所
107
As the human demand for energy has increased year by year, people are constantly looking for alternative energy sources such as solar energy, wind energy, tidal energy, geothermal energy, and biomass energy recently. However, even with the emergence and development of these renewable energy sources, it is still unable to become a large amount of energy consumed by humans today. Therefore, there is a new technique developed for harvesting the energy by nano-technique called nanogenerator. One of the potential nanogenerators is triboelectric nanogenerators (Tengs), which is proposed by Georgia Tech. and has emerged since 2012 and that is still an emerging and popular research area. In order to improve the output performance of Tengs, we can try at different aspects. For example, building up microstructure in electrode and tribo-dielectric layer (TDL) or changing the shape or size of microstructure can both increase the efficiency of Tengs. This article talks about the relationship between the thickness of TDL and open-circuit voltage or short-circuit current of a teng. Compared with static model, the dynamic model is more suitable for the output of tengs with ultra-thin thickness of TDL and we introduce one material parameter, i.e. electron-hole recombination rate (r) near the TDL in our developed dynamic model. By mathematical method, it can be derived that short-circuit current is dependent with different thickness of TDL, but open-circuit voltage is not. Furthermore, it can be found that there is a maximum current (Imax) at certain value of thickness (dmax), and the larger value of r in the material results in the smaller value of Imax and the larger value of dmax. Finally, the experimental data and the theoretical dynamic model agree very well with each other and find out the value of r not only for polydimethylsiloxane (PDMS) as TDL but also for other foreign experimental data.

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44

Li, Ying Chun, and 李瓔純. "Tellurium nanowire arrays: an efficient platform for thermoelectric nanogenerator and surface-assisted laser desorption/ionization mass spectrometry applications." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/t9e7ju.

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45

Lee李秉翰, Ping-Han, and 李秉翰. "Investigation of piezoelectric property of V and Ga doped MgZnO thin films for the application of piezoelectric nanogenerator." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/tcqt8x.

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碩士
國立成功大學
材料科學及工程學系
106
The piezoelectric nanogenerators based on MgZnO can convert the mechanical energy into electrical energy via piezoelectric effect and are considered to be the promising environmentally friendly devices. We investigate the effect of Ga doping over the piezoelectric property of MgZnO thin films deposited on p-type Si (111) substrates through RF magnetron sputtering. The deposition is carried out at a fixed temperature (250℃ ) under argon (10 sccm)/oxygen (20 sccm) atmosphere and the thickness is maintained at around 500 nm. All of the films exhibit wurtzite structure with strong [0002] preferential orientation. In addition, gallium doping influences the magnesium concentration in Ga doped MgZnO films which balances the lattice deformation formed by the larger gallium and smaller magnesium at zinc site. The piezoelectric coefficient (d33) is improved to 40.32 pm/V at a gallium concentration (XGa) of 0.041 as that with pure ZnO (d33 ~ 12.4 pm/V). Ga doped MgZnO thin films have great potential to be fabricated as piezoelectric nanogenerators.

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46

Yeh, Hsiu-Len, and 葉秀倫. "The Study of Synthesizing Vertical Aligned Multi-walled Carbon Nanotubes by Chemical Vapor Deposition and Its Application for Nanogenerator." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/73955548897249195885.

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47

(6640484), Mo Lv. "Triboelectricity and Piezoelectricity Based 3D Printed Bio-skin Sensor for Capturing Subtle Human Movements." Thesis, 2019.

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This thesis present the fabrication of 2 types of soft wearable electrical devices, utilizing the 3D printing technique. The devices are capable to detect human heart pulse waves and sound waves for health evaluation and speech recognition.

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48

(8791391), Dennis Matthew Lyle. "Exploring Ultrasonic Additive Manufacturing from Modeling to the Development of a Smart Metal-Matrix Composite." Thesis, 2020.

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The advent of additive manufacturing has opened up new frontiers in developing metal structures that can have complex geometries, composite structures made of dissimilar metals, and metal structures with embedded sensing and actuation capabilities. These types of structures are possible with ultrasonic additive manufacturing (UAM); a novel manufacturing technology that combines additive manufacturing through the ultrasonic welding of thin metal foils with computer numerical control (CNC) milling. However, the process suffers from a critical limitation, i.e., a range of build heights within which bonding between a foil and the substrate cannot be originated.
This work has two research objectives, the first is a fundamental understanding of the complex dynamic interaction between the substrate and ultrasonic horn, or sonotrode. Specifically, it focuses on the effects that specific modes of vibration have on the dynamic response of the substrate. The second objective is to utilize the UAM process to create metal structures with an embedded sensor that can detect contact or impact. In addressing the first objective, a semi-analytical model was developed to determine the response to three forcing descriptions that approximate the interfacial friction between the foil and substrate induced by sonotrode compression and excitation. Several observations can be seen in the results: as the height increases the dominant modes of vibration change, the modes of vibration excited also change during a single weld cycle as the sonotrode travels across the length of the substrate, and finally the three forcing models do not have a significant impact on the substrate response trends with height and during the weld cycle.
In addressing the second objective, three prototypes were created by embedding a triboelectric nanogenerator (TENG) sensor within an AL3003 metal-matrix. TENGs utilize contact electrification between surfaces of dissimilar materials, typically polymers, combined with electrostatic induction to generate electrical energy from a mechanical excitation. The sensors demonstrate a discernible response over a 1-5 Hz frequency range. In addition, the sensors have a linear relationship between output voltage and a mechanically applied load, and have the ability to sense contact through both touch and due to an impacting object.

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49

Gomes, Ana Alexandra Júnior. "Triboelectric Nanogenerators for Shoes." Master's thesis, 2016. https://repositorio-aberto.up.pt/handle/10216/95320.

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50

Gomes, Ana Alexandra Júnior. "Triboelectric Nanogenerators for Shoes." Dissertação, 2016. https://repositorio-aberto.up.pt/handle/10216/95320.

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Dissertations / Theses on the topic 'Nanogenerator'

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