Synthesis, characterization and electromagnetic absorbing performance of multi-step petaloid morphology VO2(M)

Abstract

VO2(D) precursor with multi-step petaloid lamination structure was prepared by hydrothermal method, and then VO2(M) sample maintaining similar morphology and geometry with that of as prepared VO2(D) was obtained by subsequent annealing. The XRD Pattern of VO2 (D) precursor and annealed samples at different temperature confirms the formation of required crystalline phases and exposes the presence of other intermediate phases. Surface morphology has been analyzed by SEM characterization, which reveals the variation in petaloid microstructure of the annealed samples at different temperatures. The reflection loss measurement results show that multi-step petaloid laminated structure VO2(M) sample has excellent microwave absorption performance. The sample annealed at 570 °C has the minimum reflection loss value of −37.99 dB at 3.5 mm, and the effective absorption bandwidth (RL < −10 dB) is up to 4.01 GHz at 1.3 mm. Detailed study shows that the excellent microwave absorption performance of the sample results from the combination of its geometry shape/surface polarization, induced loss and resistance loss. In addition, the curvature of the boundary of the laminated structure also affect the microwave absorption performance of the absorber. The discovery of this work effectively broadens the application of VO2(M) and provides a new idea for the design of new absorbing materials with tailored particle morphology.