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Cr2AlC (CAC) has attracted increasing attention due to high conductivity and excellent oxidation resistance, which is useful for high-temperature microwave absorption. However, systematic research on microwave absorption performance of CAC at high temperatures is still lacking. In this work, CAC was synthesized by salt bath method followed by annealing at 500 °C–950 °C. Effects of various annealing temperatures on compositions and electromagnetic properties were studied. Results revealed slight oxidation of CAC at annealing temperature of 500 °C, with formation of small amounts of Al2O3and Cr2O3on the surface. Increase in annealing temperature to 950 °C generated Al2O3and Cr2O3components in CAC. CAC annealed at 500 °C showed better microwave absorption properties than annealed at 950 °C and pure CAC. Effective absorption bandwidth (Reflection loss, RL < −10 dB) of CAC annealed at 500 °C was estimated to 2.3 GHz (9.7–12.0 GHz), and RLminwas −28.1 dB with thickness of 2.0 mm. The reason for this had to do with appropriate micro-oxidation, which could increase the permittivity of CAC and enhance dielectric loss capability for electromagnetic waves. In sum, these findings look promising to have referential significance for the application and promotion of CAC in the field of high temperature microwave absorption.

The emergence of organic–inorganic perovskite has provided great flexibility for creating optoelectronic devices with unprecedented performance or unique functionality. However, the perovskite films explored so far have been difficult to be patterned to arrays owing to their poor solvent and moisture stability, which usually lead to serious structural damage of perovskites. The successful preparation of perovskite microarrays with uniform shape and size is more challenging. Here we report a straightforward approach to realize single-crystalline perovskite arrays through a relatively simple pattern-selective molecular epitaxial growth. This approach is applied to create diverse shaped perovskite arrays, such as hexagon, triangle, circle, square, and rectangle. A vertically aligned perovskite photodetector displays both an ultrasensitive and ultrafast photoresponse arising from the reduction in carrier diffusion paths and the high optical absorption. This work demonstrates a general approach to creating perovskite arrays with uniform shape, size, and morphology and provides a rich platform for producing high-performance photodetectors and photovoltage devices.

MXene aerogels with a three-dimensional (3D) network structure have attracted increasing attention for lightweight electromagnetic wave absorbers. It is intriguing to expand their absorption band, i.e., to the booming terahertz (THz) region, and explore multifunctionality. Herein, we assemble MXene (Ti3C2Tx)-based hybrid aerogels into an aligned lamellar architecture using a bidirectional freezing technique. With air pore size and lamellar layer spacing comparable to THz wavelengths, high porosity of the aerogels allows nearly isotropic absorption of 99% and electromagnetic interference (EMI) shielding effectiveness with a remarkable value of 57.5 dB, in the ultrabroad bandwidth ranging from 0.5 to 3.0 THz. Simultaneous, strain-sensing response reflects the macroscopic anisotropy of the network structure of the aerogels. The improved sensitivity is measured for the out-of-lamellar layer plane under 0–30% strain. The corresponding long-term stability and durability persist over 120 stretching–releasing cycles. Our findings thus not only expand multiple functions of MXene in an anisotropic 3D macroscopic form but also clarify its nearly isotropic absorption in the THz band.

A thin microwave radar absorber with metallic dipole arrays incorporated into magnetic polymer composite is proposed to operate over a wide range of incidence angles for both TE and TM polarizations. Owing to the impedance characteristics, the magnetic absorber (MA) without dipoles cannot hold oblique-incidence-absorption for TM polarization. By introducing dipoles, the incorporated MA exhibits a broad bandwidth for reflection equal or less than -10 dB for incidence angle up to 60deg for TM polarization, and remains excellent oblique-incidence absorption for TE polarization. The improvement of oblique-incidence absorption for TM polarization is related to LC resonance caused by the embedded dipoles. The experimental results show that the proposed MA with a thickness of 2.0mm provides wide bandwidth (5.0 GHz [?]15.7 GHz for normal incidence and 4.5 GHz [?]14.8 GHz for incidence angle of 45deg) for TM polarization, which is agreement with the simulated results.

In this work, 3Ba0.7Sr0.3O*2CoO*10.8Fe2O3 and Ba2Co2Fe12O22 had been fabricated successfully by conventional ceramic process. Crystallographic structure and electromagnetic properties of two kind of hexagonal ferrite with different sintering temperature were investigated. X-ray Diffraction (XRD), Agilent-N5230A Network Analyzer were used to measure ferrite samples. The mobile phone antenna performance was analysed by HFSS. The results revealed that the main phase of two ferrite samples generated at lower temperature due to additive. The optimized parameters of ferrite are sintering temperature at 1000degC. And to emulate antenna model by HFSS find that Z-type and Y-type ferrite substrate can contribute to antenna frequency shifting, radiation efficiency were affected a little.