Microwave absorbing properties of two dimensional materials GeP5 enhanced after annealing treatment

High efficiency, lightweight, and tunable microwave absorbing materials have drawn tremendous attention. Here, we have synthesized layered GeP5 bulk at high temperature and high pressure. Then, the GeP5 nanosheets are obtained by an efficient liquid-phase exfoliation method and display excellent microwave absorption performance as a microwave absorber. The reflection loss (RL) can achieve below −10 dB in a wide range of thicknesses and microwave frequencies. For further meeting the lightweight demand of microwave absorption materials, porous germanium (GeP5-570) is obtained from GeP5 via the annealing treatment. Microwave absorption characteristics can be significantly improved after annealing treatment. The minimum RL values of porous germanium (GeP5-570) can reach −37.8 dB at a microwave frequency of 4.7 GHz under a thickness of 2.9 mm. The effective absorption bandwidth (RL< −10 dB) of GeP5-570 is 11.8–14.3 GHz with a thickness of 1.2 mm. In addition, the RL value can attain −20 dB in the frequency range of 3.8–16.1 GHz with various thicknesses from 1.0 to 3.5 mm.