Extremely Sensitive Wearable Strain Sensor with Wide Range Based on a Simple Parallel Connection Architecture

Strain sensors have attracted tremendous attention in healthcare monitoring and human-computer interaction due to their great potential in intelligent equipment. However, conventional strain sensors cannot possess high sensitivity, wide stretchable range, and low limit of detection (LoD) at the same time. Here, an ultrasensitive wearable strain sensor over a broad range based on the simple parallel connection architecture of Ir-nanoparticles-modified carbon nanotubes (Ir NPs@CNTs) and two Pt layers using a reticular patterned polymer substrate (Dragon Skin 30, (DS)) is reported. It exhibits an extremely high gauge factor of 13 590, broader strain range up to 98%, lower LoD of 0.02% strain, faster response time of 134 ms, and long-term durability above 18 000 cycles. The mechanisms of performance improvement are proposed based on the synergistic and hierarchical effects of the combined sandwich structures by parallel connection on patterned DS, including geometric effect, crack formation/propagation in parallel grooves, and tunneling-based charge carriers between IrNPs and IrNPs/CNTs. By introducing a metal nanolayer, the sensor also shows heat sensitivity at various environmental temperatures. The wearable sensors have been utilized for human-motion detection with improved comprehensive performance, indicating their promising applications in flexible electronics and artificial intelligent fields.