Electromagnetic (EM) absorbers play an increasingly essential role in the electronic information age, even toward the coming “intelligent era”. The remarkable merits of heterointerface engineering and its peculiar EM characteristics inject a fresh and infinite vitality for designing high‐efficiency and stimuli‐responsive EM absorbers. However, there still exist huge challenges in understanding and reinforcing these interface effects from the micro and macro perspectives. Herein, EM response mechanisms of interfacial effects are dissected in depth, and with a focus on advanced characterization as well as theoretical techniques. Then, the representative optimization strategies are systematically discussed with emphasis on component selection and structural design. More importantly, the most cutting‐edge smart EM functional devices based on heterointerface engineering are reported. Finally, current challenges and concrete suggestions are proposed, and future perspectives on this promising field are also predicted.
The exploration of ultra-wideband electromagnetic shielding materials is still a huge challenge to eliminate electromagnetic interference from various frequencies electronic devices in military and civil fields. Herein, a free-standing graphene...
Heterostructures
with a rich phase boundary are attractive for surface-mediated microwave
absorption (MA) materials. However, understanding the MA mechanisms
behind the heterogeneous interface remains a challenge. Herein, a
phosphine (PH3) vapor-assisted phase and structure engineering
strategy was proposed to construct three-dimensional (3D) porous Ni12P5/Ni2P heterostructures as microwave
absorbers and explore the role of the heterointerface in MA performance.
The results indicated that the heterogeneous interface between Ni12P5 and Ni2P not only creates sufficient
lattice defects for inducing dipolar polarization but also triggers
uneven spatial charge distribution for enhancing interface polarization.
Furthermore, the porous structure and proper component could provide
an abundant heterogeneous interface to strengthen the above polarization
relaxation process, thereby greatly optimizing the electromagnetic
parameters and improving the MA performance. Profited by 3D porous
heterostructure design, P400 could achieve the maximum reflection
loss of −50.06 dB and an absorption bandwidth of 3.30 GHz with
an ultrathin thickness of 1.20 mm. Furthermore, simulation results
confirmed its superior ability (14.97 dB m2 at 90°)
to reduce the radar cross section in practical applications. This
finding may shed light on the understanding and design of advanced
heterogeneous MA materials.
Mechano-optical systems with on-demand adaptability and
a broad
spectrum from the visible to microwave are critical for complex multiband
electromagnetic (EM) applications. Most existing material systems
merely have dynamic optical or microwave tunability because their
EM wave response is strongly wavelength-dependent. Inspired by cephalopod
skin, we develop an adaptive multispectral mechano-optical system
based on bilayer acrylic dielectric elastomer (ADE)/silver nanowire
(AgNW) films, which reconfigures the surface morphology between wrinkles
and cracks via mechanical contraction and stretching. Such morphological
evolution regulates the direct transmission/reflection and scattering
behavior of visible–infrared light and simultaneously alters
the conductive network in a AgNW film to influence its microwave characteristics.
The designed system features switching between visible–infrared–microwave
transparency and opacity, continuous regulation, wide spectral window
(0.38–15.5 μm and 24,200–36,600 μm), excellent
recyclability (500 times), and rapid response time (<1 s). These
grant the system great potential as platforms for various promising
applications such as smart windows, switchable EM devices, dynamic
thermal management, adaptive visual stealth, and human motion detection.
Wearable devices with efficient thermal management and electromagnetic interference (EMI) shielding are highly desirable for improving human comfort and safety. Herein, a multifunctional wearable carbon fibers (CF) @ polyaniline (PANI) / silver nanowires (Ag NWs) composites with a “branch-trunk” interlocked micro/nanostructure were achieved through "three-in-one" multi-scale design. The reasonable assembly of the three kinds of one-dimensional (1D) materials can fully exert their excellent properties i.e., the superior flexibility of CF, the robustness of PANI, and the splendid conductivity of AgNWs. Consequently, the constructed flexible composite demonstrates enhanced mechanical properties with a tensile stress of 1.2 MPa, which was almost 6 times that of the original material. This is mainly attributed to the fact that the PNAI (branch) was firmly attached to the CF (trunk) through polydopamine (PDA), forming a robust interlocked structure. Meanwhile, the composite possesses excellent thermal insulation and heat preservation capacity owing to the synergistically low thermal conductivity and emissivity. More importantly, the conductive path of the composite established by the three 1D materials greatly improved its EMI shielding property and Joule heating performance at low applied voltage. This work paves the way for rational utilization of the intrinsic properties of 1D materials, as well as provides a promising strategy for designing wearable electromagnetic protection and thermal energy management devices.
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