Mechanically Regulated Ionic P-N Junctions Enable Passive and Stable Tactile Sensing with Intelligent Perception

Tactile sensing technologies are essential for enabling perception in robotics, healthcare, and industrial systems. Active tactile sensors offer simple structures and high sensitivity, but their reliance on continuous power restricts their use in autonomous and portable platforms. Passive tactile sensors based on the piezoionic effect can generate bioelectrical-like signals yet maintaining long-term stability under both static and dynamic mechanical stimuli remains challenging. Here, we introduce a self-powered, low-energy, and highly stable bioinspired passive tactile sensor that employs a mechanically regulated interfacial ionic p-n junction (IPNJ) integrated with microchannels. The coexistence of mobile ions and fixed polymer chains within p-type and n-type ionic hydrogels, together with pyramid microstructures and porous nylon-mesh channels, enables continuously tunable interfacial contact and mechanical modulation between the two hydrogels. The resulting ionogel sensor autonomously and stably acquires tactile signals from diverse fruits, which are subsequently analyzed using a convolutional neural network to achieve high-precision surface texture perception and object classification, area under curve (AUC) values of 99.4% and 99.3%, respectively. This work demonstrates a robust and sustainable tactile sensing mechanism with strong potential for applications in next-generation human machine interaction systems.