ORCID Profile
0000-0003-0674-808X
Current Organisations
Huazhong University of Science and Technology
,
University of Wollongong
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Publisher: American Chemical Society (ACS)
Date: 17-08-2017
Abstract: The rapid development of microscaled piezoelectric energy harvesters has provided a simple and highly efficient way for building self-powered sensor systems through harvesting the mechanical energy from the ambient environment. In this work, a self-powered microfluidic sensor that can harvest the mechanical energy of the fluid and simultaneously monitor their characteristics was fabricated by integrating the flexible piezoelectric poly(vinylidene fluoride) (PVDF) nanofibers with the well-designed microfluidic chips. Those devices could generate open-circuit high output voltage up to 1.8 V when a droplet of water is flowing past the suspended PVDF nanofibers and result in their periodical deformations. The impulsive output voltage signal allowed them to be utilized for droplets or bubbles counting in the microfluidic systems. Furthermore, the devices also exhibited self-powered sensing behavior due to the decreased voltage litude with increasing input pressure and liquid viscosity. The drop of output voltage could be attributed to the variation of flow condition and velocity of the droplets, leading to the reduced deformation of the piezoelectric PVDF layer and the decrease of the generated piezoelectric potential.
Publisher: Elsevier BV
Date: 08-2021
Publisher: Proceedings of the National Academy of Sciences
Date: 02-2022
Abstract: Streams of fluids, particulates, and other flowing media are difficult to control after they have left a nozzle. Here, we present the noncontact manipulation of a free-flowing stream of liquid metal. Such streams form by electrochemically lowering the interfacial tension. The electrochemical reactions make the streams into soft current–carrying conductors presenting minimal resistance to manipulation via the Lorentz force in the magnetic field. Meanwhile, the movement of the stream induces a secondary force arising from Lenz’s law that causes the manipulated streams to levitate in unique shapes. This work, which exploits these forces in a visually stunning manner, enables shaping of fluids in a noncontact manner.
Publisher: Royal Society of Chemistry (RSC)
Date: 2020
DOI: 10.1039/D0TC03152F
Abstract: An atomic-scale study of the oxygen annealing effect on the piezoelectricity enhancement of (K,Na)NbO 3 nanorods via structure, strain and dipolar displacement vector analyses.
Publisher: American Chemical Society (ACS)
Date: 29-04-2021
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C7RA13506H
Abstract: Pb(Zr,Ti)O 3 nanorod arrays with outstanding piezoelectric response and a high d 33 of 1600 pm V −1 were synthesized by a one-step hydrothermal process.
Publisher: AIP Publishing
Date: 22-05-2017
DOI: 10.1063/1.4984094
Abstract: Orthorhombic (K,Na)NbO3 (KNN) nanorod arrays with the [110]-orientation were grown on SrTiO3 substrates by the hydrothermal method. The nanorods exhibited greatly enhanced piezoelectric performance, with the d33 piezoelectric coefficient increasing from 140 pm/V to 360 pm/V, after annealing in oxygen at temperatures ranging from 500 °C to 800 °C. The high temperature annealing process was accompanied by severe volatilization of K, which modified the K/Na ratio closer to 1:1. Thus, orthorhombic-tetragonal (O-T) phase boundaries appeared, which improved the piezoelectric property. Moreover, surface oxygen vacancies were passivated in the high-temperature oxygen atmosphere, which would reduce the charge density in the nanorods and contribute to the enhanced piezoelectricity. Therefore, excellent piezoelectricity in the KNN nanorod arrays was driven by the combination of the O-T phase boundaries and the oxygen vacancy passivation. This work demonstrates that KNN has great potential in piezoelectric materials area.
Publisher: AIP Publishing
Date: 02-04-2018
DOI: 10.1063/1.5021378
Abstract: Lead-free (K,Na)NbO3 (KNN) nanorod arrays were synthesized with the assistance of a Nb: SrTiO3 single-crystal substrate through the hydrothermal process. The evolutions of the morphology, composition, and structure of the as-synthesized KNN nanorods with the increase in reaction time were investigated. The results confirmed that the increase in reaction time up to 3 h led to the increase in the length and aspect ratio of the well-aligned KNN nanorods. All s les have K-rich orthorhombic crystal structures, while the diffraction peaks shifted towards a higher degree. The peak shifts should be attributed to the increase in the Na content in the KNN lattice, which could decrease the lattice parameters owing to the small ionic radius of Na+ than that of K+. Moreover, the increase in reaction time also resulted in the suppression of oxygen vacancies on the surface of the KNN nanorods. These evolutions of the composition and crystal structure, as well as the decrease in the defect content, lead to great enhancement of the nanorod's piezoelectric response, as their d33 value was increased from 19 to 64 pm/V. These results demonstrated the significant impact of reaction time on the hydrothermal growth of high-performance lead-free KNN one-dimensional nanomaterials.
Publisher: American Physical Society (APS)
Date: 13-03-2023
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7RA01359K
Abstract: High-quality (K,Na)NbO3 nanorod arrays with [110]-oriented spontaneous polarization and piezoelectric response were utilized for building high-output piezoelectric energy harvesters.
Publisher: IOP Publishing
Date: 16-09-2016
Publisher: Elsevier BV
Date: 03-2021
Publisher: Hindawi Limited
Date: 2015
DOI: 10.1155/2015/165631
Abstract: Recently, the nanogenerators which can convert the mechanical energy into electricity by using piezoelectric one-dimensional nanomaterials have exhibited great potential in microscale power supply and sensor systems. In this paper, we provided a comprehensive review of the research progress in the last eight years concerning the piezoelectric nanogenerators with different structures. The fundamental piezoelectric theory and typical piezoelectric materials are firstly reviewed. After that, the working mechanism, modeling, and structure design of piezoelectric nanogenerators were discussed. Then the recent progress of nanogenerators was reviewed in the structure point of views. Finally, we also discussed the potential application and future development of the piezoelectric nanogenerators.
No related grants have been discovered for Yahua He.