Highly Efficient Microwave Absorption of Magnetic Nanospindle-Conductive Polymer Hybrids by Molecular Layer Deposition

Oxidative molecular layer deposition (oMLD) was applied to fabricate conductive polymer-magnetic material core-shell microwave absorbers in this work. One dimensional Fe₃O₄-poly(3,4-ethylenedioxythiophene) (PEDOT) nanospindles with controllable PEDOT thickness were successfully synthesized. Their absorption performance was evaluated in the 2-18 GHz frequency range. With the advantage of oMLD, PEDOT shell thicknesses can be controlled precisely. Because the permittivity of Fe₃O₄-PEDOT nanospindles obviously increases while their permeability decreases slightly with the PEDOT cycles, the properties can be tuned effectively by only adjusting the PEDOT cycle number. With a proper PEDOT shell thickness, excellent reflection characteristics can be obtained. Remarkably high absorption strength (-55.0 dB at 16.2 GHz) and good absorption bandwidth (4.34 GHz less than -10 dB) were realized. Such excellent performance is better than that reported previously for most magnetic material-based absorbers. Considering the precise controllability and excellent absorption performance of the prepared microwave absorbers, we believe that oMLD is a facile synthetic route for microwave absorbers.