Architecture Design and Interface Engineering of Self-assembly VS4/rGO Heterostructures for Ultrathin Absorbent

Abstract

The employment of microwave absorbents is highly desirable to address the increasing threats of electromagnetic pollution. Importantly, developing ultrathin absorbent is acknowledged as a linchpin in the design of lightweight and flexible electronic devices, but there are remaining unprecedented challenges. Herein, the self-assembly VS₄/rGO heterostructure is constructed to be engineered as ultrathin microwave absorbent through the strategies of architecture design and interface engineering. The microarchitecture and heterointerface of VS₄/rGO heterostructure can be regulated by the generation of VS₄ nanorods anchored on rGO, which can effectively modulate the impedance matching and attenuation constant. The maximum reflection loss of 2VS₄/rGO40 heterostructure can reach - 43.5 dB at 14 GHz with the impedance matching and attenuation constant approaching 0.98 and 187, respectively. The effective absorption bandwidth of 4.8 GHz can be achieved with an ultrathin thickness of 1.4 mm. The far-reaching comprehension of the heterointerface on microwave absorption performance is explicitly unveiled by experimental results and theoretical calculations. Microarchitecture and heterointerface synergistically inspire multi-dimensional advantages to enhance dipole polarization, interfacial polarization, and multiple reflections and scatterings of microwaves. Overall, the strategies of architecture design and interface engineering pave the way for achieving ultrathin and enhanced microwave absorption materials.

Keywords: Architecture design; Interface; Microwave absorption; Self-assembly.

Fig. 1

a Schematic illustration of the synthesis processes for self-assembly VS₄/rGO heterostructure. SEM image of b VS₄ nanorods, c rGO architecture, and d VS₄/rGO heterostructure. e, f TEM images of VS₄/rGO heterostructure with different magnification. g HRTEM images of VS₄ nanorods showing the d-spacing of 0.56 nm in the (110) plane and rGO showing the d-spacing of 0.37 nm in (0 0 2) plane

Fig. 2

a TEM image of VS₄/rGO heterostructure for the EDS mapping. b EDS spectra and the table of elemental composition. c TEM image corresponding to EDS elemental mappings: V, S, C and O. d XRD patterns of VS₄ nanorods and VS₄/rGO heterostructures. e Raman spectra of VS₄ nanorods, rGO and VS₄/rGO heterostructure

Fig. 3

XPS spectra of VS₄/rGO heterostructures: a V 2p, b S 2p, c C 1s. d TGA curves of VS₄/rGO heterostructures. e Nitrogen adsorption–desorption isotherms. f Different BET surface areas of VS₄/rGO heterostructures

Fig. 4

Permittivity and dielectric loss tangent of VS₄/rGO heterostructures in the frequency range of 2–18 GHz: a ε′, b ε", c Tan δ_ε. d Cole–Cole semicircles for VS₄/rGO heterostructure

Fig. 5

RL curves and 3D presentations of VS₄/rGO heterostructures at the thicknesses of 1 to 6 mm in the frequency range of 2–18 GHz: a, b 2VS₄/rGO20-30%; c, d 2VS₄/rGO40-30%; e, f 2VS₄/rGO60-40%

Fig. 6

a 3D RL presentations of rGO, VS₄ nanorods, VS₄/rGO nanocomposite, and VS₄/rGO heterostructure (2VS₄/rGO40-30%). b Attenuation constant α of rGO, VS₄ nanorods, VS₄/rGO nanocomposite, and VS₄/rGO heterostructures (2VS₄/rGO40-30%). c Frequency dependence of RL, attenuation constant α and |Z_in/Z₀| at 1.5 mm for 2VS₄/rGO40-30%. d RL of different VS₄/rGO heterostructures at 1.4 mm. Comparison of some typical graphene-based absorbents for e EAB and f RL_max at different thickness. g Charge density of the interfaces (I) VS₄(-2 0 4)/rGO (1 0 0) interface, (II) VS₄(0 2 0)/rGO (1 0 0) interface, (III) VS₄(1 1 0)/rGO (1 0 0) interface. h Charge density difference of (I) VS₄(-2 0 4)/rGO (1 0 0) and (II) VS₄(1 1 0)/rGO (1 0 0) interface

Fig. 7

Schematic illustration for the microwave absorption mechanism of VS₄/rGO heterostructure