Kinetics Compensation of Interfacial Built-in Electric Field Facilitated by Oriented Evolution from Physical Adsorption to Covalent Bridging for Efficient Electromagnetic Wave Absorption

Enhancing the interfacial built-in electric field (BIEF) is a core strategy for boosting electromagnetic (EM) absorption performance. Conventional approaches rely solely on enlarging the Fermi level difference (ΔEf) as the thermodynamic driving force to regulate BIEF, which are strictly limited by the intrinsic electronic structures of materials, confining BIEF enhancement within a “thermodynamic ceiling”. To this end, this study proposes an oriented evolution of interfacial bonding strategy, introducing the kinetics compensation factor into BIEF modulation for the first time to break the inherent limitation of traditional ΔEf-dependent thermodynamic regulation. By tuning the sulfur vacancy concentration in graphene quantum dot@indium sulfide (GQDs/In₂S₃) heterostructures, the heterointerface evolves directionally from physical adsorption to strong In-O covalent bridging, constructing highly efficient atomic-scale charge transport channels. Despite a decrease in ΔEf from 1.06 to 0.47 eV, the kinetics enhancement of interfacial charge transfer can still approximately triple the BIEF strength. The reinforced BIEF significantly promotes interfacial polarization loss, delivering a minimum reflection loss of −50.8 dB and an effective absorption bandwidth of 7.0 GHz. This work elucidates the core mechanism of kinetics compensation for the thermodynamic ceiling in ΔEf-dependent BIEF modulation, and provides a novel design framework for high-performance EM absorption materials. © 2026 Wiley-VCH GmbH.