Hierarchical Design and Interfacial Work Function Modulation Endow Fe2O3/SnO2/Carbon Foam Improved Sensibility for Rehabilitation Training.

The escalating demands for continuous, accurate, and non-invasive monitoring of physiological motions in modern rehabilitation medicine have significantly propelled the development of high-performance flexible sensors with sufficient sensitivity to detect weak signals and suitable detection range to accommodate wide amplitudes. Herein, 3D Fe2O3/SnO2/carbon foams (Fe2O3/SnO2/CFs) with gradient microstructure and tunable interface work function are constructed. The n-n Fe2O3/SnO2 heterojunction facilitates interfacial charge transfer, substantially reducing the initial resistance (R0↓). Concurrently, within carbon foam, the vertically-grown hierarchical architectures composed of Fe2O3 micro-cones with gradient stiffness and surface-distributed SnO2 nanoparticles synergistically generate stress concentration at Fe2O3 tips and the proliferation of conductive pathways upon compression, thereby amplifying resistance variation (ΔR↑) for improved sensitivity and extended detection range. Capitalizing on these structural advantages, Fe2O3/SnO2/CF-based flexible pressure sensor exhibits an elevated sensitivity of 479 kPa-1, a wide sensing range of 0-50 kPa, and exceptional stability. Furthermore, smart insoles integrated with Fe2O3/SnO2/CF sensors enable real-time gait analysis, demonstrating its capability to give guidance on personalized rehabilitation training and therapeutic management through precise assessments of neurological and traumatic disorders.