有调节性介电性质的导电金属有机框架,用于增强电磁波吸收
Xue Zhang1, Xue-Lei Tian1, Yutian Qin2
1Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, School of Materials Science and Engineering, Shandong University, Jinan 250061, P. R. China.
ACS nano
|June 23, 2023
概括
有调节性介电性质的导电金属有机框架 (MOF) 显示出优异的电磁波 (EMW) 吸收. Cu-HHTP 和 Zn-HHTP MOF 显示出显著的性能,推进了 EMW 衰减机制.
科学领域:
- 材料科学 材料科学 材料科学
- 纳米技术纳米技术
- 化学 化学 化学
背景情况:
- 金属有机框架 (MOF) 为电磁波 (EMW) 吸收提供可调节的特性.
- 导电MOF (cMOF) 对先进的EMW减弱应用具有前景.
研究的目的:
- 准备具有可调节介电性质的棒状导电MOF (cMOF),用于量身定制的EMW吸收.
- 研究构成,电荷传输和微观结构对电磁波吸收性能的影响.
- 推进对MOF中的EMW减弱机制的理解.
主要方法:
- 使用各种金属离子 (Zn,Cu,Co,Ni) 和六三烯 (HHTP) 连接物合成棒状cMOF.
- 描述cMOF的组成,电荷传输,晶体结构和微观结构.
- 介电性质和EMW吸收性能的评估,包括反射损失 (RL) 和有效吸收带宽.
主要成果:
- 在Cu-HHTP cMOF中,在2.9毫米厚度下,最小反射损失 (RLmin) 为-63.55dB,有效吸收带宽为5.2GHz.
- Zn-HHTP cMOF 显示出优异的 S 波段吸收 (2-4 GHz),在 1.9 毫米厚度下,RLmin 为 -62.8 dB.
- 增强的导电和极化损失归因于联效应,终端组和形状异构性.
结论:
- 该研究为EMW吸收中的cMOFs提供了结构-属性关系的机制性见解.
- 量身定制的cMOF,特别是Cu-HHTP和Zn-HHTP,显示出有效吸收EMW的巨大潜力.
- 这项工作为设计功能MOF材料用于EMW减弱应用提供了指导方针.
相关概念视频
01:27π Electron Effects on Chemical Shift: Overview
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0, resulting in...
01:25Eddy Currents
Since eddy currents occur only in conductors, magnets can separate metals from other materials. For example, in a recycling center, trash is dumped in batches down a ramp, beneath which lies a powerful magnet. Conductors in the trash are slowed by eddy currents, while nonmetals in the trash move on, separating from the metals. This works for all metals, not just ferromagnetic ones.
Other major applications of eddy currents appear in metal detectors and the braking systems of trains and roller...
Other major applications of eddy currents appear in metal detectors and the braking systems of trains and roller...
01:20Inductors
An inductor, also known as a choke, is a circuit component created to have a specific inductance. Inductors are among the crucial circuit components used in modern electronics, along with resistors and capacitors. They serve as a barrier against changes in a circuit's current. An inductor tends to suppress current changes in an alternating-current circuit that are faster than desired. In a direct-current circuit, an inductor aids in preserving a constant current despite changes in the applied...
01:31Ferromagnetism
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
01:17Magnetic Damping
Eddy currents can produce significant drag on motion, called magnetic damping. For instance, when a metallic pendulum bob swings between the poles of a strong magnet, significant drag acts on the bob as it enters and leaves the field, quickly damping the motion.
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
If, however, the bob is a slotted metal plate, the magnet produces a much smaller effect. When a slotted metal plate enters the field, an emf is induced by the change in flux; however, it is less effective because the slots limit the...
01:30The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...