Layered Aluminum for Electromagnetic Wave Absorber with Near-Zero Reflection

Taehoon Kim, Hyung Wan Do, Kyu Jong Choi, Sungsoon Kim, Minwoo Lee, Taeyoung Kim, Byung Kyu Yu, Jinwoo Cheon, Byung Wook Min, Wooyoung Shim

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)


Ideal electromagnetic (EM) wave absorbers can absorb all incident EM waves, regardless of the incident direction, polarization, and frequency. Absorptance and reflectance are intrinsic material properties strongly correlated with electrical conductivity; hence, achieving perfect absorptance with zero reflectance is challenging. Herein, we present a design strategy for preparing a nearly ideal EM absorber based on a layered metal that maximizes absorption by utilizing multiple internal reflections and minimizes reflection using a monotonic gradient of intrinsic impedance. This approach was experimentally verified using aluminum nanoflakes prepared via topochemical etching of lithium from Li9Al4, and the impedance-graded structure was obtained through the size-based sorting behavior of aluminum nanoflakes sinking in dispersion. Unlike in traditional shielding materials, strong absorption (26.76 dB) and negligible reflectivity (0.04 dB) with a ratio of >103 can be achieved in a 120 μm thick film. Overall, our findings exhibit potential for developing a novel class of antireflective shielding materials.

Original languageEnglish
Pages (from-to)1132-1140
Number of pages9
JournalNano letters
Issue number2
Publication statusPublished - 2021 Jan 27

Bibliographical note

Publisher Copyright:
© 2021 American Chemical Society. All rights reserved.

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering


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