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>Distinct plasmon resonance enhanced microwave absorption of strawberry-like Co/C/Fe/C core–shell hierarchical flowers via engineering the diameter and interparticle spacing of Fe/C nanoparticles
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Distinct plasmon resonance enhanced microwave absorption of strawberry-like Co/C/Fe/C core–shell hierarchical flowers via engineering the diameter and interparticle spacing of Fe/C nanoparticles
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机译：通过设计Fe / C纳米颗粒的直径和颗粒间间距，不同的等离子体共振增强了草莓状Co / C / Fe / C核-壳分层花的微波吸收
Strawberry-like Co/C/Fe/C core–shell hierarchical flowers (CSHFs) consisting of separated Fe/C nanoparticles (NPs) anchoring on a Co HF surface were prepared by decomposing Fe(CO) _(5) in the presence of Co HFs. Changing the decomposition temperature ( T _(d) ) and Fe(CO) _(5) volume ( δ ) could also facilely modulate the phase structure, surface morphology and composition of the products. The low T _(d) and small δ helped form Co/C/Fe/C CSHFs with a strawberry-like plasmon surface. The diameter and interparticle spacing-dependent electromagnetic properties were investigated at 2–18 GHz. The interparticle-spacing-to-diameter ratio determines the plasmon resonance and coupling. The permittivity and permeability enhanced by strong plasmon resonance were exhibited by Co/C/Fe/C CSHFs formed at δ = 3–4 mL with the interparticle-spacing-to-diameter ratio of 1.36–0.76. The collective oscillation of the conduction band electrons and near field on the Co/C and Fe/C surfaces generated a surface plasmon resonance and coupling, which were responsible for significantly enhanced permittivity and permeability with negative values. In view of the synergistic effect of the enhanced permittivity and permeability, dual dielectric relaxations, dual magnetic resonances, high attenuation and good impedance matching, Co/C/Fe/C CSHFs with particle size of 110 ± 20–380 ± 100 nm and interparticle spacing of 150 ± 50 nm were excellent absorbers that feature strong absorption, broad bandwidth and light weight. An optimal reflection loss ( R _(L) ) of ?45.06 was found at 17.92 GHz for an absorber thickness of 1.6 mm, and the frequency range ( R _(L) ≤ ?20 dB, 99% absorption) was over 2–18 GHz. Our findings demonstrated that optimally designed plasmonic heterostructures must be fabricated to improve microwave absorption performances for future applications.
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机译：草莓状的Co / C / Fe / C核-壳分层花（CSHF）由固定在Co HF表面的分离的Fe / C纳米颗粒（NPs）组成，方法是在Fe（CO）_（5）存在下分解氟化氢。改变分解温度（T _（d））和Fe（CO）_（5）体积（δ）也可以容易地调节产物的相结构，表面形态和组成。低的T_（d）和小的δ有助于形成具有草莓状等离子体表面的Co / C / Fe / C CSHF。在2–18 GHz的频率下研究了直径和与粒子间距有关的电磁特性。粒子间距与直径之比决定了等离子体激元的共振和耦合。 Co / C / Fe / C CSHF在δ= 3–4 mL时形成，粒子间间距与直径之比为1.36–0.76，表现出强等离子体共振增强的介电常数和磁导率。 Co / C和Fe / C表面上的导带电子和近场的集体振荡产生了表面等离子体激元共振和耦合，这导致介电常数和磁导率显着提高（负值）。鉴于介电常数和磁导率增强，双重介电弛豫，双重磁共振，高衰减和良好的阻抗匹配的协同效应，粒径为110±20–380±100 nm的Co / C / Fe / C CSHF和粒子间150±50 nm的间距是出色的吸收剂，具有强吸收，宽带宽和重量轻的特点。对于厚度为1.6 mm的吸收体，在17.92 GHz处发现最佳反射损耗（R _（L））为？45.06，频率范围（R _（L）≤？20 dB，99％吸收）超过2– 18 GHz。我们的发现表明，必须制造出优化设计的等离子体异质结构，以提高微波吸收性能，以备将来应用。
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