Conductive Bimetal–Organic Frameworks with Volcano-Type Fine-Tuned Dielectric Properties for Electromagnetic Wave Absorption

Inherently conductive metal-organic frameworks (cMOFs) deliver significant potential for tailoring charge transport characteristics in functional applications. Herein, we synthesize a bimetallic NiCu-HHTP cMOF with precisely controllable interlayer spacing, enabling fine-tuning of the charge transport, electronic band structure, and dielectric properties. By exploiting differences in self-polarization effects between active ions, NiCu-HHTP exhibits an inverted volcano-type interlayer spacing variation through controlled modulation of ion proportions and produces volcano-type tunable dielectric properties. At an optimal Ni/Cu ratio, the bimetallic cMOFs demonstrate an optimal dielectric performance, which enables synergy between an efficient attenuation coefficient and optimal impedance matching. Consequently, Ni3Cu1-HHTP could harvest a minimum reflection loss of -70.3 dB and an effective absorption bandwidth of 5.12 GHz. This study clarifies mechanisms of microstructure-function correlations in bimetallic cMOFs and provides a protocol for precise modulation of interlayer spacing and electronic band structure in cMOF-based electromagnetic wave materials.