MOF-on-MOF Heterostructured Films for Broadband Electromagnetic Wave Absorption and Thermal Management.

Understanding the correlation between heterointerface engineering and electromagnetic (EM) properties in hybrid materials, including metal-organic frameworks, is critical to advancing next-generation high-performance electromagnetic wave (EMW) absorbers. As the first demonstration of an all-MOF heterostructure film that achieves both high-performance EM absorption and thermal management, herein, a heterostructured MOF film, NUS-8@Cu3(HHTP)2, was fabricated by hybridizing the solution-processable MOF NUS-8 with the highly conductive MOF Cu3(HHTP)2. This prototypical heterostructure NUS-8@Cu3(HHTP)2 was found to exhibit effective modulation of its dielectric loss behavior. The optimal composite exhibits a notable minimum reflection loss (RLmin) of -42.9 dB and an ultra-wide effective absorption bandwidth (EAB) of 8.47 GHz at 2.5 mm, setting up new benchmarks over conductive MOFs and MOF composites reported thus far. When the optimized NUS-8@Cu3(HHTP)2 composite was incorporated into an epoxy matrix, a stable and robust EMW absorbing patch featuring an RLmin of -33.2 dB and an EAB of 6.38 GHz was achieved. Of particular importance is that NUS-8@Cu3(HHTP)2 epoxy composites demonstrate an enhanced thermal conductivity, eliciting efficient heat dissipation for reliable use in thermally demanding environments. Put simply, this work introduces a new strategy for designing high-performance EM absorbers through heterostructure engineering.