Synergistic Band and Multiscale Hybrid Engineering in Polycrystalline TiO 2 for Enhanced Spatial Charge Polarization Relaxation

Abstract Hybrid structures offer a versatile design platform for semiconductor micro‐nano devices, enabling precise modulation of charge transport and energy conversion/storage. However, optimizing the spatial charge response of hybrids via band structure engineering remains challenging for efficient electromagnetic wave (EMW) absorption. Here, a novel synergistic band and multiscale hybrid engineering is proposed to tailor spatial charge relaxation loss of hybrid semiconductor nanocrystal (HSNCs) nanocomposites. The HSNCs exhibit a unique Co[ Fm‐3m ]/TiO 2 [ I41/amd ]/TiO 2 [ P42/mnm ] polycrystalline structure, driven by tunable coordination and electrostatic interactions between metal‐organic frameworks with distinct coordination topologies and MXene nanosheets. The differentiated charge and energy band structure of the nanocrystals in each phase of HSNCs promotes the delocalization of positive and negative charges and the aggregation of space charges at the interface, thereby promoting spatial charge relaxation, which significantly enhances dielectric loss and electromagnetic energy attenuation, as evidenced by a minimum reflection loss of −45.52 dB. Finally, this work elucidates the hybrid structure‐property relationship in semiconductor nanocomposites, establishing a dynamic polarization physical model across multiple scales, including grain boundaries, unit cells, and atoms, offering valuable perspectives for exploring novel EMW absorption materials.