Scalable one-step casting of a stretchable and flexible triboelectric sensor array for multi-functional sensing

摘要

Triboelectric sensor arrays (TSAs), particularly stretchable variants, hold immense potential for advancing human-machine interaction and personalized healthcare. However, existing fabrication methods often suffer from complex instrumentation, material limitations, and inefficiencies that hinder rapid prototyping. In this work, a low-cost and scalable one-step casting strategy is proposed for fabricating a stretchable TSA using Ecoflex and a conductive sponge electrode. A single-electrode triboelectric nanogenerator was systematically optimized in terms of surface morphology, electrode thickness, and Ecoflex thickness, achieving an output voltage of ~640 V, a short-circuit current of ~7.5 μA, and a peak power density of 2.82 W/m², with stable performance over 12,000 cycles. Notably, the device maintained functionality under 125% strain and exhibited enhanced output at 56.25% strain, demonstrating excellent mechanical robustness. Scalable TSA configurations ranging from 2×2 to 4×4 pixels were developed for multifunctional sensing applications. a 2×2 TSA enabled LED control and real-time visual positioning; a 4×4 TSA was used as a self-powered keyboard for numerical input; and a 3×3 TSA integrated with a LabVIEW interface allowed touchscreen-like motion tracking. For gait monitoring, a 2×2 TSA-integrated insole mapped plantar pressure and achieved 99.435% user identification accuracy using a lightweight 1D-CNN. When extended to multi-gait conditions (slow/normal walking, slow running), a MobileNetV4 model with channel attention achieved 96.531% accuracy across 12 identity-activity combinations. This work demonstrates a versatile and accessible platform for scalable, self-powered stretchable electronics, with broad implications for wearable systems, soft robotics, and AI-assisted healthcare.