Atomic Valence Reversal-Induced Polarization Resonance Spurs Highly Efficient Electromagnetic Wave Absorption in α-Fe<sub>2</sub>O<sub>3</sub>@Carbon Microtubes.

Ren, Hengdong; Zhu, Tongshuai; Feng, Lei; Wu, Qifan; Wang, Ka; Yun, Xinjie; Zhu, Haogang; Chen, Jian et al. · Nano Lett · 2024

basic_science · Level V

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Abstract

Variegation and complexity of polarization relaxation loss in many heterostructured materials provide available mechanisms to seek a strong electromagnetic wave (EMW) absorption performance. Here we construct a unique heterostructured compound that bonds α-Fe<sub>2</sub>O<sub>3</sub> nanosheets of the (110) plane on carbon microtubes (CMTs). Through effective alignment between the Fermi energy level of CMTs and the conduction band position of α-Fe<sub>2</sub>O<sub>3</sub> nanosheets at the interface, we attain substantial polarization relaxation loss via novel atomic valence reversal between Fe(III) ↔ Fe(III<sup>-</sup>) induced with periodic electron injection from conductive CMTs under EMW irradiation to give α-Fe<sub>2</sub>O<sub>3</sub> nanosheets. Such heterostructured materials possess currently reported minimum reflection loss of -84.01 dB centered at 10.99 GHz at a thickness of 3.19 mm and an effective absorption bandwidth (reflection loss ≤ -10 dB) of 7.17 GHz (10.83-18 GHz) at 2.65 mm. This work provides an effective strategy for designing strong EMW absorbers by combining highly efficient electron injection and atomic valence reversal.