Gradient‐Conductivity Architecture Enables Synchronous Enhancement of Sensitivity and Detection Range in Multifunctional All‐Paper Sensors

Abstract

Paper‐based sensors offer a sustainable platform for wearable electronics, yet their performance is fundamentally constrained by the intrinsic “contact‐jumping” behavior of hierarchical cellulose fibers, which causes abrupt conduction transitions, early current saturation, and an inevitable sensitivity–detection range trade‐off. Here, we introduce a stepwise conductivity‐gradient, open‐circuit‐triggered architecture that spatially reprograms pressure‐induced electron pathways within cellulose networks. By integrating in situ grown AgNPs on MXene‐modified fibers with a pressure‐activated MXene interdigitated electrode, the sensor enables cascaded pathway evolution that delays current saturation and establishes a progressively tunable piezoresistive response. Multiscale simulations and interfacial charge analyses reveal strain‐induced Ag–MXene polarization and charge delocalization, which expand available conduction channels and lower transport barriers. Benefiting from this gradient‐engineered mechanism, the sensor achieves an ultrahigh sensitivity of 1365.87 kPa⁻¹, a broad detection range of 0.7 Pa–203.2 kPa, a 0.7 Pa detection limit, and excellent durability over 10 000 cycles. The hierarchical network also affords strong EMI shielding and high breathability, enabling stable on‐skin operation and multifunctional sensing.