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Yong Shi

Bio: Yong Shi is an academic researcher from Stevens Institute of Technology. The author has contributed to research in topics: Nanofiber & Lead zirconate titanate. The author has an hindex of 14, co-authored 70 publications receiving 1994 citations. Previous affiliations of Yong Shi include Massachusetts Institute of Technology.


Papers
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Journal ArticleDOI
TL;DR: A piezoelectric nanogenerator based on PZT nanofibers, with a diameter and length of approximately 60 nm and 500 microm, was reported, aligned on interdigitated electrodes of platinum fine wires and packaged using a soft polymer on a silicon substrate.
Abstract: Energy harvesting technologies that are engineered to miniature sizes, while still increasing the power delivered to wireless electronics,(1, 2) portable devices, stretchable electronics,(3) and implantable biosensors,(4, 5) are strongly desired. Piezoelectric nanowire- and nanofiber-based generators have potential uses for powering such devices through a conversion of mechanical energy into electrical energy.(6) However, the piezoelectric voltage constant of the semiconductor piezoelectric nanowires in the recently reported piezoelectric nanogenerators(7-12) is lower than that of lead zirconate titanate (PZT) nanomaterials. Here we report a piezoelectric nanogenerator based on PZT nanofibers. The PZT nanofibers, with a diameter and length of approximately 60 nm and 500 μm, were aligned on interdigitated electrodes of platinum fine wires and packaged using a soft polymer on a silicon substrate. The measured output voltage and power under periodic stress application to the soft polymer was 1.63 V and 0.03 ...

818 citations

Journal ArticleDOI
TL;DR: In this article, the design and testing of a resonance frequency tunable energy harvesting device using a magnetic force technique is presented, which enabled resonance tuning to ±20% of the untuned resonant frequency.
Abstract: Vibration energy harvesting is an attractive technique for potential powering of wireless sensors and low power devices. While the technique can be employed to harvest energy from vibrations and vibrating structures, a general requirement independent of the energy transfer mechanism is that the vibration energy harvesting device operate in resonance at the excitation frequency. Most energy harvesting devices developed to date are single resonance frequency based, and while recent efforts have been made to broaden the frequency range of energy harvesting devices, what is lacking is a robust tunable energy harvesting technique. In this paper, the design and testing of a resonance frequency tunable energy harvesting device using a magnetic force technique is presented. This technique enabled resonance tuning to ±20% of the untuned resonant frequency. In particular, this magnetic-based approach enables either an increase or decrease in the tuned resonant frequency. A piezoelectric cantilever beam with a natural frequency of 26 Hz is used as the energy harvesting cantilever, which is successfully tuned over a frequency range of 22‐32 Hz to enable a continuous power output 240‐280 μW over the entire frequency range tested. A theoretical model using variable damping is presented, whose results agree closely with the experimental results. The magnetic force applied for resonance frequency tuning and its effect on damping and load resistance have been experimentally determined. (Some figures in this article are in colour only in the electronic version)

651 citations

Journal ArticleDOI
TL;DR: Aligned piezoelectric (PZT) nanofibres were fabricated by electrospinning using PZT sol?gel as a precursor as mentioned in this paper, and the average diameter of these fibres could be controlled to range from 52 to 150nm by varying the concentration of poly(vinyl pyrrolidone) in the precursor.
Abstract: Aligned piezoelectric (PZT) nanofibres were fabricated by electrospinning using PZT sol?gel as precursor. A pure perovskite phase with an average grain size of 10?nm was obtained at 650??C. The average diameter of these fibres could be controlled to range from 52 to 150?nm by varying the concentration of poly(vinyl pyrrolidone) (PVP) in the precursor. Special samples of PZT nanofibres were deposited across the microfabricated trenches on a silicon wafer. Atomic force microscopy (AFM) was used to measure the mechanical properties of a single nanofibre. The elastic modulus of an individual PZT nanofibre that was obtained was 42.99?GPa, which was smaller than that of a thin-film PZT. The possible reasons for the reduction in elastic modulus of the nanofibres were discussed.

94 citations

Journal ArticleDOI
Jinwei Li1, Xi Chen1, Nan Ai1, Jumin Hao1, Qi Chen1, Stefan Strauf1, Yong Shi1 
TL;DR: In this article, the photoanodes were used as photoanode to fabricate dye-sensitized solar cells and it was found that the nanoparticle doped solar cells have a significantly increased photocurrent density resulting in a 25% improved conversion efficiency compared to undoped panels.

87 citations

Journal ArticleDOI
TL;DR: In this article, a single lead ziroconate titanate (PZT) nanofiber under bending using a nanomanipulator inside a scanning electron microscope chamber was presented.
Abstract: Direct piezoelectric potential measurement of single lead ziroconate titanate (PZT) nanofiber under bending using a nanomanipulator inside a scanning electron microscope chamber was presented. The PZT nanofibers, with the diameter and length around 100 nm and 70–100 μm, respectively, were aligned across trenches on a silicon substrate with a thermally grown oxide diffusion barrier and evaporated gold electrodes. A potential of ∼0.4 mV was generated when a bending moment was applied to a PZT nanofiber with an effective length of 4 μm by a tungsten tip of the nanomanipulator. The experiment demonstrated the feasibility of using these PZT nanofibers for nanoscale sensing, actuation, and energy harvesting.

78 citations


Cited by
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01 Jan 2007

1,932 citations

Journal ArticleDOI
03 Sep 2008
TL;DR: The principles and state-of-art in motion-driven miniature energy harvesters are reviewed and trends, suitable applications, and possible future developments are discussed.
Abstract: Energy harvesting generators are attractive as inexhaustible replacements for batteries in low-power wireless electronic devices and have received increasing research interest in recent years. Ambient motion is one of the main sources of energy for harvesting, and a wide range of motion-powered energy harvesters have been proposed or demonstrated, particularly at the microscale. This paper reviews the principles and state-of-art in motion-driven miniature energy harvesters and discusses trends, suitable applications, and possible future developments.

1,781 citations

Journal ArticleDOI
Wei Zeng1, Lin Shu1, Qiao Li1, Song Chen1, Fei Wang1, Xiaoming Tao1 
TL;DR: This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products.
Abstract: Fiber-based structures are highly desirable for wearable electronics that are expected to be light-weight, long-lasting, flexible, and conformable Many fibrous structures have been manufactured by well-established lost-effective textile processing technologies, normally at ambient conditions The advancement of nanotechnology has made it feasible to build electronic devices directly on the surface or inside of single fibers, which have typical thickness of several to tens microns However, imparting electronic functions to porous, highly deformable and three-dimensional fiber assemblies and maintaining them during wear represent great challenges from both views of fundamental understanding and practical implementation This article attempts to critically review the current state-of-arts with respect to materials, fabrication techniques, and structural design of devices as well as applications of the fiber-based wearable electronic products In addition, this review elaborates the performance requirements of the fiber-based wearable electronic products, especially regarding the correlation among materials, fiber/textile structures and electronic as well as mechanical functionalities of fiber-based electronic devices Finally, discussions will be presented regarding to limitations of current materials, fabrication techniques, devices concerning manufacturability and performance as well as scientific understanding that must be improved prior to their wide adoption

1,626 citations

Journal ArticleDOI
TL;DR: Progress in nanogenerators for mechanical energy harvesting is reviewed, mainly including two key technologies: flexible piezoelectric nanognerators (PENGs) and flexible triboelectrics nanogsenerators (TENGs).
Abstract: Flexible nanogenerators that efficiently convert mechanical energy into electrical energy have been extensively studied because of their great potential for driving low-power personal electronics and self-powered sensors. Integration of flexibility and stretchability to nanogenerator has important research significance that enables applications in flexible/stretchable electronics, organic optoelectronics, and wearable electronics. Progress in nanogenerators for mechanical energy harvesting is reviewed, mainly including two key technologies: flexible piezoelectric nanogenerators (PENGs) and flexible triboelectric nanogenerators (TENGs). By means of material classification, various approaches of PENGs based on ZnO nanowires, lead zirconate titanate (PZT), poly(vinylidene fluoride) (PVDF), 2D materials, and composite materials are introduced. For flexible TENG, its structural designs and factors determining its output performance are discussed, as well as its integration, fabrication and applications. The latest representative achievements regarding the hybrid nanogenerator are also summarized. Finally, some perspectives and challenges in this field are discussed.

1,325 citations

Journal ArticleDOI
TL;DR: A comprehensive overview of the progress that has been made within the context of 1D ZnO nanostructures synthesized via wet chemical methods can be found in this paper, where the synthetic methodologies and corresponding growth mechanisms, different structures, doping and alloying, position-controlled growth on substrates, and finally, their functional properties as catalysts, hydrophobic surfaces, sensors, and in nanoelectronic, optical, optoelectronics, and energy harvesting devices.
Abstract: One-dimensional (1D) ZnO nanostructures have been studied intensively and extensively over the last decade not only for their remarkable chemical and physical properties, but also for their current and future diverse technological applications. This article gives a comprehensive overview of the progress that has been made within the context of 1D ZnO nanostructures synthesized via wet chemical methods. We will cover the synthetic methodologies and corresponding growth mechanisms, different structures, doping and alloying, position-controlled growth on substrates, and finally, their functional properties as catalysts, hydrophobic surfaces, sensors, and in nanoelectronic, optical, optoelectronic, and energy harvesting devices.

1,247 citations