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189 results on '"Bai, Yaocai"'

10. Utilization of a magnetic field-driven microscopic motion for piezoelectric energy harvesting

Author

Kim, Sanggon, Ico, Gerardo, Bai, Yaocai, Yang, Steve, Lee, Jung-Ho, Yin, Yadong, Myung, Nosang V, and Nam, Jin

Subjects
Nanotechnology, Bioengineering, Affordable and Clean Energy, Physical Sciences, Chemical Sciences, Technology, Nanoscience & Nanotechnology
Abstract

In spite of the recent advances in the development of high performing piezoelectric materials, their applications are typically limited to the direct conversion of mechanical impact energy to electrical energy, potentially risking mechanical failures. In this study, we developed piezoelectric poly(vinylidenefluoride-trifluoroethylene) (P(VDF-TrFE)) nanofibers integrated with SiO2-shelled Fe3O4 magnetic nanoparticles, to utilize magnetic energy to reliably drive the piezoelectric effect. Specifically, we show that the shape of the magnetic nanoparticles exerts a significant effect on the efficiency of the magneto-mechano-electrical energy conversion as magnetic nanorods exhibit approximately 70% enhancement in electric field generation under cyclic magnetic fields as compared to nanospheres. Under an alternating magnetic field of 200 mT, the magnetic nanorod-piezoelectric nanofiber composite generated a peak-to-peak voltage of approximately 30 mVp-p with a superior durability without any performance degradation after over 1 million cycles. This study demonstrates the potential of magnetic-field responsive, piezoelectric-based materials in energy harvesting applications from non-mechanical energy sources.

Published
2019

19. Dichroic switching of core–shell plasmonic nanoparticles on reflective surfaces.

Author

Liang, Tian, Li, Zhiwei, Bai, Yaocai, and Yin, Yadong

Subjects
PLASMONICS, LIGHT absorption, LIGHT scattering, NANOPARTICLES, SURFACE plasmon resonance
Abstract

Plasmonic metal nanostructures can simultaneously scatter and absorb light, with resonance wavelength and strength depending on their morphology and composition. This work demonstrates that unique dichroic effects and high‐contrast colour‐switching can be achieved by leveraging the resonant scattering and absorption of light by plasmonic nanostructures and the specular reflection of the resulting transmitted light. Using core/shell nanostructures comprising a metal core and a dielectric shell, we show that their spray coating on reflective substrates produces dichroic films that can display colour switching at different viewing angles. The high‐contrast colour switching, high flexibility in designing multicolour patterns, and convenience for large‐scale production promise their wide range of applications, including anticounterfeiting, mechanochromic sensing, colour display, and printing. [ABSTRACT FROM AUTHOR]

Published
2024
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37. Structural Engineering of Optical Nanomaterials

Author

Bai, Yaocai

Subjects
Materials Science, Nanoscience, Nanotechnology, colloidal synthesis, hollow structures, localized surface plasmon resonance, nanomaterials, optical property, resorcinol formaldehyde
Abstract

Optical nanomaterials have attracted tremendous interest from a large community of researchers because of their widespread applications. The optical properties are closely related the structures of nanomaterials, thus making the structural engineering over nanomaterials in a controlled manner an important topic. This dissertation discusses our efforts in the engineering and applications of optical nanomaterials including noble metal nanostructures and hollow nanostructures.Noble metal nanostructures possess novel optical properties due to localized surface plasmon resonances. Controllable synthesis of noble metal nanostructures with desired morphology and optical properties is highly desirable. In this work, we attempt to prepare anisotropic Ag/Au alloy nanorods with homogenous compositions through a high-temperature annealing process. Alloy nanorods exhibit strong surface plasmon resonances with high stability upon etching. Tunable and fascinating optical properties are achieved through controlling over aspect ratios and compositions of the nanorods.Improved understandings on the properties of resorcinol-formaldehyde (RF) resins will benefit the colloidal synthesis of RF-based nanomaterials. In this study, the chemical stability and the evolution of both surface properties and chemical structures of RF resin spheres are systematically studied, which provide guidance for the rational design and fabrication of various hollow nanostructures. Based on the new understandings, an extension of the surface-protected etching strategy has been adopted for the preparation and engineering of hollow RF nanostructures. A RF-template-engaged redox reaction method is proposed and utilized for rational synthesis of mesoporous hollow manganese oxide nanostructures. Visible resonant Mie scattering properties are theoretically simulated and experimentally demonstrated.Finally, a couple of novel optical demonstrations based on the design and structural engineering of nanostructures are presented. The first one is the design of plasmonic dichroic film on a mirrored substrate, which has been realized by spray-coating core-shell nanostructures. By structural engineering over the core-shell particles, dichroic film with multi-colors has been successfully created, which holds great potential in anti-counterfeiting. The other one is related to the modulation of light transmittance and the drying process of hollow nanostructures. Au nanoparticles are incorporated into the hollow structures and employed to probe the drying process.

Published
2017

49. Front Cover: Dichroic switching of core–shell plasmonic nanoparticles on reflective surfaces (EXP2 3/2024).

Author

Liang, Tian, Li, Zhiwei, Bai, Yaocai, and Yin, Yadong

Subjects
PLASMONICS, NANOPARTICLES, LIGHT absorption, LIGHT scattering
Abstract

Unique dichroic effects and high‐contrast color‐switching can be achieved by leveraging the resonant scattering and absorption of light by plasmonic nanostructures and the specular reflection of the resulting transmitted light. The cover illustrates a dichroic film of core‐shell plasmonic nanospheres displaying varying colors at different viewing angles. Cover design is generated with the assistance of AI technology..By Tian Liang; Zhiwei Li; Yaocai Bai and Yadong YinReported by Author; Author; Author; Author [Extracted from the article]

Published
2024
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