Preparation and high-performance microwave absorption of hierarchical dendrite-like Co superstructures self-assembly of nanoflakes

Yu, Minggao; Wang, Lirui; Yang, Pingan; Fu, Jie

doi:10.1088/1361-6528/aa9045

Cited by 30 publications

(10 citation statements)

References 63 publications

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“…The obtained results indicate the bandwidth of g‐C 3 N 4 /PMMA > g‐C 3 N 4 /CuS/PMMA > CuS/PMMA, which has been insightfully studied. According to the Debye dipolar relaxation theory, the relationship between ε′ and ε″ can be deduced by

{({normalε}^{'} - \frac{{normalε}_{s} + {normalε}_{\infty}}{2})}^{2} + {(ε^{''})}^{2} = {(\frac{ε_{s} - ε_{\infty}}{2})}^{2}

equation, where ε ∞ and ε s correspond to permittivity at the infinite frequency and static permittivity . The equation exhibits that the curve ε′ versus ε″ is a semicircle denoted as a Cole–Cole semicircle.…”

Section: Resultsmentioning

confidence: 99%

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Peymanfar

Karimi²,

Fallahi³

2019

J of Applied Polymer Sci

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In this study, a broadband, intense, novel, and promising microwave-absorbing nanocomposite was prepared using graphite-like carbon nitride (g-C 3 N 4 )/CuS suspended in poly(methyl methacrylate) (PMMA) medium. The g-C 3 N 4 nanosheets were synthesized by heating the urea as well as the CuS nanoparticles, and g-C 3 N 4 /CuS nanocomposites were prepared using a solvothermal method and then were separately molded by a PMMA solution to investigate their microwave-absorbing characteristics. The Fourier transform infrared and X-ray powder diffraction were used to characterize the g-C 3 N 4 , CuS, and CuS/g-C 3 N 4 nanostructures, which confirmed that the pure structure of the nanomaterials has been synthesized. The optical properties of the nanostructures were also investigated by diffuse reflection spectroscopy analysis. Accordingly, the Kubelka-Munk theory suggested significant narrow band gap for g-C 3 N 4 /CuS nanocomposite (0.27 eV), facilitating electron jumping and conductive loss. The morphology of the structures was examined using field emission scanning electron microscopy micrographs, illustrating that the uniform hexagonal structures of the CuS nanoplates have been formed and the CuS two-dimensional structures were uniformly distributed on the g-C 3 N 4 nanosheets. Finally, the microwave-absorbing properties of the CuS, g-C 3 N 4 , and g-C 3 N 4 /CuS were investigated by PMMA as a host. The microwaveabsorbing properties were evaluated using a vector network analyzer. The results illustrated that the maximum reflection loss of the g-C 3 N 4 /PMMA nanocomposite was −71.05 dB at 14.90 GHz with a thickness of 2.00 mm, demonstrating a 1.70 GHz bandwidth >30 dB, as well as g-C 3 N 4 /CuS/PMMA nanocomposite absorbed 7.30 GHz bandwidth of more than 10 dB with a thickness of 1.80 mm along the x-and ku-band frequency. The obtained results introduced the PMMA as a capable microwave-absorbing substrate. Besides, the g-C 3 N 4 /CuS/PMMA nanocomposite demonstrated metamaterial property and abundant attenuation constant.

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{({normalε}^{'} - \frac{{normalε}_{s} + {normalε}_{\infty}}{2})}^{2} + {(ε^{''})}^{2} = {(\frac{ε_{s} - ε_{\infty}}{2})}^{2}

Section: Resultsmentioning

confidence: 99%

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Peymanfar

Karimi²,

Fallahi³

2019

J of Applied Polymer Sci

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“…Recently, nanomaterials have attracted wide attention to overcome these shortcomings of MAMs with advantages of their low density, board adsorption bandwidth, and high impedance matching, as small size and complex structures can introduce additional loss pathways. A library of nanostructures, such as flowerlike, nanoflake, nanochain, and hierarchical dendrite, have been rationally fabricated toward improving the microwave absorption properties. More importantly, complex nanostructures with hollow interior including core–shell, hollow, porous, and yolk shell structures have been also reported, exhibiting excellent microwave absorption properties.…”

Section: Introductionmentioning

confidence: 99%

Balancing Dielectric Loss and Magnetic Loss in Fe–NiS₂/NiS/PVDF Composites toward Strong Microwave Reflection Loss

Gao

Wang

et al. 2020

ACS Appl. Mater. Interfaces

145

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Lightweight, broad-band, and highly efficient microwave-absorbing materials (MAMs) with tunable electromagnetic properties are in high demand. However, the absorption properties are limited by the simple loss mechanism in commonly used absorbing materials. Here, we tested the microwave-absorbing properties of Fe–NiS2/NiS/poly(vinylidene fluoride) (PVDF) in the frequency range of 2–18 GHz. For the 2.5% Fe–NiS2/NiS/PVDF with the filling content of 20 wt %, the maximum reflection loss can reach −61.72 dB at 14.88 GHz, and the bandwidth can reach 3.8 GHz with the reflection loss value below −10 dB. Loss mechanisms of different composites were analyzed on the basis of their magnetic and dielectric properties using both experimental and computational methods. The results indicate that strong microwave absorption property is achieved through a balancing of dielectric loss and magnetic loss. These findings present a new strategy for the future design of MAMs.

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“…The broadened microwave absorption bandwidth of the pristine nanoparticles was predictable from the natural resonance equation,

f_{normalr} = \frac{{r H}_{normala}}{2 π}

where f r , r , and H a are the resonance frequency, gyromagnetic ratio, and anisotropy field which H a can be defined by

H_{normala} = \frac{2}{M_{s} {normalμ}_{0}} true| K_{1} true|

equation where K 1 is the anisotropy constant, exhibiting a compromise between the M s and the bandwidth of the absorber . According to the eddy current loss ( C 0 ) effect, calculated by the

C_{0} = f^{- 1} μ^{″} {(μ^{'})}^{- 2}

equation and free electron theory, came from

ϵ^{″} \propto σ / f 2 π ϵ_{0}

where σ is the electrical conductivity, the electrical conductivity has a significant influence on the dielectric and the magnetic dissipation of microwave irradiation which can be originated from the intrinsic properties of the CuCr 2 O 4 nanoparticles. The conductive loss is the important factor affecting the microwave absorption properties.…”

Section: Resultsmentioning

confidence: 99%

Preparation and Characterization of Copper Chromium Oxide Nanoparticles Using Modified Sol‐Gel Route and Evaluation of Their Microwave Absorption Properties

Peymanfar

Khodamoradipoor²

2019

Physica Status Solidi (a)

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In this study, simple, broadband, robust, and affordable microwave absorbing nanocomposites are prepared using CuCr2O4 nanoparticles as guests and silicone rubber or poly(vinylidene fluoride) (PVDF) as host. Firstly, the pristine and modified CuCr2O4 nanoparticles are obtained by the conventional citrate gel method in the absence and presence of sucrose as a novel capping agent in the experimental steps. X‐ray powder diffraction (XRD) patterns confirms that the CuCr2O4 nanoparticles are synthesized. Moreover, morphologies, chemical functional groups, and optical properties are studied using field emission scanning electron microscopy (FE‐SEM), Fourier transform infrared (FT‐IR), and diffuse reflection spectroscopy (DRS), respectively. The vibrating sample magnetometer (VSM) analysis reveals weak magnetic properties for the nanoparticles and confirms that the capping agent change the magnetic properties. Finally, bare and modified copper chromium oxide nanoparticles are separately molded with silicone rubber or PVDF to compare dipole and interfacial polarization. Besides, using a vector network analyzer (VNA) along the x and ku‐band frequency, novel organic precursor effects on their microwave absorption properties are examined. According to the obtained results, the maximum reflection loss of the modified CuCr2O4/PVDF is −65.57 dB at 14 GHz with 2 mm thickness and the CuCr2O4/PVDF nanocomposite absorbs a bandwidth of 7.73 GHz more than 10 dB with a thickness of 2 mm. Interestingly, novel one type filler lead to significant microwave absorbing properties as well as organic capping agent reinforced maximum microwave absorption also PVDF improves absorption bandwidth.

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Preparation and high-performance microwave absorption of hierarchical dendrite-like Co superstructures self-assembly of nanoflakes

Cited by 30 publications

References 63 publications

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Balancing Dielectric Loss and Magnetic Loss in Fe–NiS₂/NiS/PVDF Composites toward Strong Microwave Reflection Loss

Preparation and Characterization of Copper Chromium Oxide Nanoparticles Using Modified Sol‐Gel Route and Evaluation of Their Microwave Absorption Properties

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Preparation and high-performance microwave absorption of hierarchical dendrite-like Co superstructures self-assembly of nanoflakes

Cited by 30 publications

References 63 publications

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Novel, promising, and broadband microwave‐absorbing nanocomposite based on the graphite‐like carbon nitride/CuS

Balancing Dielectric Loss and Magnetic Loss in Fe–NiS2/NiS/PVDF Composites toward Strong Microwave Reflection Loss

Preparation and Characterization of Copper Chromium Oxide Nanoparticles Using Modified Sol‐Gel Route and Evaluation of Their Microwave Absorption Properties

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Balancing Dielectric Loss and Magnetic Loss in Fe–NiS₂/NiS/PVDF Composites toward Strong Microwave Reflection Loss